JP2008095581A - Fuel property determination device for internal combustion engine - Google Patents

Abstract

An object of the present invention is to provide a fuel property determination device for an internal combustion engine that can achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.
A main tank 21 and a sub tank 22 are provided, and a communication cutoff valve 25 is provided between them. Among these, a sub fuel pipe 42 is connected to the sub tank 22 so that fuel can be supplied to the cylinder group A. The main tank 21 is connected to a fuel supply pipe 27 and a main fuel pipe 41 so that fuel can be supplied to the cylinder group B. When the fuel is supplied, the main tank 21 and the sub tank 22 are shut off, so that the cylinder group A can be operated with the fuel stored in the sub tank 22 before refueling. Further, the cylinder group B can be operated with fuel including fuel that has been refueled, and the fuel properties can be determined. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.
[Selection] Figure 1

Description

  The present invention relates to a fuel property determination device for an internal combustion engine. In particular, the present invention relates to a fuel property determination device for an internal combustion engine provided in an internal combustion engine that can be operated with a plurality of types of fuel having different properties.

  Internal combustion engines are configured to be operable by burning fuel in a combustion chamber, but some conventional internal combustion engines are operable with a plurality of fuels having different properties. In such an internal combustion engine, when a plurality of types of fuels having different properties are supplied to the fuel tank, for example, the fuel is separated using a means for separating these fuels such as a polymer film, and the fuel is stored in the internal combustion engine. Supply separately. Thus, even when a plurality of types of fuel having different properties are supplied to the fuel tank, the fuel tank can be operated with one type of fuel when the internal combustion engine is operated. However, when separating the fuel in the fuel tank in this way, it is necessary to provide a means for separating the fuel tank, so that depending on the means, there is a risk that the manufacturing cost may increase or separation may not be performed reliably. Thus, some conventional internal combustion engines have fuel tanks that are divided according to the fuel to be refueled.

  For example, in the fuel storage device for an engine described in Patent Document 1, two fuel tanks are provided, and switching means for switching so as to guide the supplied fuel to one of the two tanks is provided. Furthermore, an alcohol concentration detection means for detecting the alcohol concentration of the fuel in the fueled state is provided to detect the alcohol concentration of the fuel supplied, and the switching means is switched according to the detected alcohol concentration. Thus, even when a plurality of fuels having different properties are supplied, the fuel can be supplied to one of the two fuel tanks according to the alcohol concentration. As a result, fuels having different properties can be easily used according to the operating conditions of the internal combustion engine. Further, although two fuel tanks are provided, it is only necessary to provide one fuel supply port, so that it is possible to suppress an oil supply mistake when supplying fuel having different properties.

JP-A-5-209565

Here, when the internal combustion engine is operated with fuel having different properties, it is necessary to change the operation state of the internal combustion engine according to the property of the fuel, for example, by changing the air-fuel ratio. However, when a plurality of fuels having different properties are supplied to the fuel tank and the fuel is supplied to the internal combustion engine, there is a possibility that problems such as drivability failure may occur. For example, in the case of an internal combustion engine that can be operated with a plurality of types of fuel having different properties, when the fuel in the fuel tank is reduced and fuel is supplied, the fuel that has a different property from the fuel originally contained in the fuel tank is used. There is a case to refuel. In this case, when newly refueled fuel is supplied to the internal combustion engine, the internal combustion engine determines the property of the fuel from an O ₂ sensor or the like when operating with the fuel, and the operation of the internal combustion engine is performed in accordance with the property of the fuel. Switch state. However, this determination may take time, and there may be a problem that the air-fuel ratio becomes unstable or the emission deteriorates during the determination.

  The present invention has been made in view of the above, and provides a fuel property determination device for an internal combustion engine capable of achieving both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a fuel property determination device for an internal combustion engine according to the present invention communicates with a fuel supply passage which is a passage through which the fuel passes when fuel is supplied to an internal combustion engine having a plurality of cylinders. A main tank, a sub-tank communicating with the main tank, a first communication blocking means capable of switching between communication and blocking between the main tank and the sub-tank, and a part of the plurality of cylinders. A sub-passage that can supply at least the fuel stored in the sub-tank to the first cylinder group, and a second cylinder group that is the cylinder other than the first cylinder group among the plurality of cylinders, and at least the main cylinder A main passage capable of supplying the fuel stored in the tank; and when the fuel is supplied from the oil supply passage, the first tank is connected to the main communication passage. Supply fuel that shuts off the sub tank and supplies only the fuel stored in the sub tank to the first cylinder group and supplies only the fuel stored in the main tank to the second cylinder group And a fuel property determining unit configured to determine a fuel property at least in the second cylinder group when the fuel is supplied from the fuel supply passage.

  In the present invention, when the fuel is supplied from the oil supply passage to the main tank, the main tank and the sub tank are shut off by the first communication cutoff means. Therefore, the newly supplied fuel is supplied only to the main tank, and the sub tank Only the fuel before refueling is stored. Further, when fuel is supplied from the oil supply passage, only the fuel stored in the sub tank is supplied to the first cylinder group, and only the fuel stored in the main tank is supplied to the second cylinder group. To do. Thereby, in the 2nd cylinder group, the property of the newly refueled fuel can be determined by burning the fuel in the main tank. Further, in the first cylinder group, the fuel property is already determined by burning the fuel in the sub tank, and the fuel can be operated with the fuel used for the operation of the internal combustion engine before refueling. Obtainable. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.

  In the internal combustion engine fuel property determination apparatus according to the present invention, the main passage and the sub-passage are in communication with each other, and the communication between the main passage and the sub-passage can be switched. The fuel supply control means is connected via a shut-off means, and causes the second communication shut-off means to shut off the main passage and the sub-passage when the fuel is supplied from the fuel supply passage. It is characterized by.

  In the present invention, there is provided second communication blocking means for blocking the main passage and the sub passage when fuel is supplied from the fuel supply passage. For this reason, when the fuel is supplied from the oil supply passage, the main passage and the sub passage are shut off by the second communication cut-off means, so that the fuel before refueling is more reliably supplied to the first cylinder group. The fuel is supplied from the sub-tank through the passage, and the second cylinder group is more reliably supplied from the main tank through the main passage with the fuel in which the fuel before refueling and the newly supplied fuel are mixed. As a result, it is possible to more reliably determine the properties of the fuel newly supplied in the second cylinder group, and to burn the fuel used for the operation of the internal combustion engine from before the fuel supply in the first cylinder group. A stable operating state can be obtained. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.

  In the fuel property determination apparatus for an internal combustion engine according to the present invention, the supply fuel control means may be configured such that when the fuel property determination by the fuel property determination means is completed, the main passage and the sub-passage are connected to the second communication cutoff means. It is characterized by communicating with a passage.

  In the present invention, when the fuel property determination is completed, the main passage and the sub passage are communicated with the second communication blocking means, so that the fuel in the main tank and the fuel in the sub tank are connected to the first cylinder group and the first cylinder group. It can be freely supplied to the two-cylinder group as needed. Further, since the fuel supplied from the main tank and the sub tank is the fuel after the fuel property is determined, the internal combustion engine is operated by burning this fuel in the first cylinder group and the second cylinder group. Therefore, the operation according to the fuel property can be performed, and a stable operation state can be obtained more reliably. As a result, drivability can be improved more reliably when fuels having different properties are supplied to the internal combustion engine.

  Further, in the fuel property determination apparatus for an internal combustion engine according to the present invention, the supply fuel control means includes the main tank and the sub tank as the first communication cutoff means when the fuel property determination by the fuel property determination means is completed. And communicating with each other.

  In this invention, when the fuel property determination is completed, the main tank and the sub tank are communicated with the first communication cut-off means, so that the newly refueled fuel can be supplied to the sub tank, and the fuel in the main tank And the fuel in the sub tank have the same fuel properties. For this reason, the fuel in the sub-tank and the fuel in the main tank can be supplied to the first cylinder group and the second cylinder group with the same properties, and these fuels can be supplied after the properties are determined. Since the fuel is used, the first cylinder group and the second cylinder group can be operated in accordance with the fuel properties. Thereby, the stable driving | running state can be obtained more reliably. As a result, drivability can be improved more reliably when fuels having different properties are supplied to the internal combustion engine.

  Further, in the fuel property determination device for an internal combustion engine according to the present invention, the fuel property determination unit is configured to perform the operation after the fuel property determination is completed and the first communication blocking unit communicates the main tank and the sub tank. A fuel property determination is further performed according to the fuel in the main tank and the fuel in the sub tank before the main tank and the sub tank communicate with each other.

  In this invention, after the main tank and the sub tank are communicated, the fuel property determination is performed according to the fuel in the main tank and the fuel in the sub tank before communicating the main tank and the sub tank. The property of the fuel used for the operation of the internal combustion engine can be determined more accurately. As a result, it is possible to more reliably achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.

  The fuel property determination apparatus for an internal combustion engine according to the present invention further includes a fuel correction determination means for determining whether or not the fuel during the fuel property determination can be used by correcting the supply amount to the internal combustion engine. The fuel property determination means reduces the number of cylinders that perform the fuel property determination when the fuel correction determination means determines that the fuel supply amount cannot be corrected and used. Features.

  In the present invention, when the fuel correction determining means determines that the fuel being determined cannot be used after correcting the supply amount to the internal combustion engine, the number of cylinders for which the fuel property is determined is reduced. In other words, if the fuel under fuel property determination cannot be corrected, more time is spent to determine the fuel property. Therefore, the number of cylinders for determining the fuel property is reduced, and the fuel before refueling with new fuel is used. Increase the number of cylinders to be operated. Thereby, the operating state of the internal combustion engine during fuel property determination can be more reliably stabilized, and by increasing the number of cylinders operated with fuel before refueling new fuel, the operating state is stabilized, The fuel property determination can be performed with the remaining cylinders, and the fuel property determination can be performed more reliably. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.

  In the fuel property determination apparatus for an internal combustion engine according to the present invention, the main passage is branched into a plurality of branches, and the plurality of branched main passages become a plurality of branched main passages and communicate with the sub passages, respectively. And a part of the branch main passages of the plurality of branch main passages communicates and shuts off the branch main passage and the sub passage, and communicates and shuts off the branch main passage and the main tank. The supply fuel control means is connected to the switchable third communication cutoff means, and the supply fuel control means is connected to the third communication cutoff means when the fuel property determination means reduces the number of cylinders for which the fuel property determination is performed. The passage and the sub passage are communicated with each other, and the branch main passage and the main tank are blocked.

  In the present invention, the main passage is divided into a plurality of branches to form a plurality of branch main passages, and further, the third communication blocking means is provided, so that a part of the branch main passages can communicate with the sub passages. Blocking and communication between the branch main passage and the main tank can be switched. Thus, when reducing the number of cylinders that perform fuel property determination during fuel property determination, the third communication blocking means is switched to connect the branch main passage and the sub passage, and the branch main passage and the main tank. By shutting off, fuel in the sub tank can be supplied to some cylinders of the second cylinder group. For this reason, the cylinder which can be drive | operated with the fuel in a subtank can be increased. Therefore, when the fuel under fuel property determination cannot be corrected, the number of cylinders that can be stably operated by using the fuel in the sub-tank more reliably can be increased more reliably. The fuel property determination can be performed more reliably with the remaining cylinders in the state. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.

  The fuel property determination device for an internal combustion engine according to the present invention has an effect that it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine.

  Embodiments of a fuel property determination device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic diagram of an internal combustion engine provided with a fuel property determination device for an internal combustion engine according to a first embodiment of the present invention. The internal combustion engine 1 shown in the figure is provided with a fuel property determination device 10 according to Embodiment 1 of the present invention. The internal combustion engine 1 has a plurality of cylinders 3. The plurality of cylinders 3 are formed so that the cylinders 3 are directed in two directions with respect to a crankshaft (not shown) that is an output shaft during operation of the internal combustion engine 1, and the cylinders 3 are thus formed. The internal combustion engine 1 is a so-called V-type internal combustion engine 1. In this V-type internal combustion engine 1, four cylinders 3 form one set to form a bank 6, and two banks 6 are provided. That is, the internal combustion engine 1 has eight cylinders 3. Of the two banks 6, one bank 6 is a first bank 7 and the other bank 6 is a second bank 8. As described above, among the cylinders 3 provided in the first bank 7 and the second bank 8, the cylinder 3 provided in the first bank 7 is a cylinder group A which is a first cylinder group. The provided cylinder 3 is a cylinder group B which is a second cylinder group. That is, the cylinder group A includes a part of the plurality of cylinders 3 included in the internal combustion engine 1, and the cylinder group B includes cylinders other than the cylinder group A among the plurality of cylinders 3 included in the internal combustion engine 1. 3

  The internal combustion engine 1 in which a plurality of cylinders 3 are formed in this way includes an intake pipe 11 that supplies a mixture of fuel and air to the cylinders 3 and exhaust gas that is discharged from the internal combustion engine 1 when the internal combustion engine 1 is in operation. Is connected to an exhaust pipe 13 which is an exhaust passage through which. Among these, the intake pipe 11 is branched into an intake pipe 11 connected to the cylinder 3 of the first bank 7 and an intake pipe 11 connected to the cylinder 3 of the second bank 8. Further, it branches corresponding to each cylinder 3 and is connected to each cylinder 3. Thus, in the intake pipe 11 connected to each cylinder 3, a portion where an injector 12 capable of injecting fuel into the air flowing in the intake pipe 11 branches in correspondence to each cylinder 3 in the intake pipe 11. Is provided. That is, the injector 12 is provided for each cylinder 3. Since the intake pipe 11 is provided with the injector 12 as described above, fuel is injected into the intake pipe 11 by the injector 12 to generate a mixture of fuel and air in the intake pipe 11. An air-fuel mixture can be supplied into the cylinder 3. Each cylinder 3 is provided so that the air-fuel mixture supplied from the intake pipe 11 can be combusted.

  Further, in the intake pipe 11 formed in this way, a portion where the intake pipe 11 is connected to the cylinder 3 of the first bank 7 and a cylinder of the second bank 8 in the flow direction of the air flowing through the intake pipe 11. A throttle valve 15 capable of adjusting the flow rate of the air flowing through the intake pipe 11 is provided on the upstream side of the portion connected to 3. Further, the intake pipe 11 is provided with an air flow meter 16 that can detect the flow rate of the air flowing through the intake pipe 11 on the upstream side of the throttle valve 15.

The exhaust pipe 13 is connected to each cylinder 3 in the same manner as the intake pipe 11. That is, the exhaust pipe 13 is branched into a plurality corresponding to each cylinder 3 similarly to the intake pipe 11, and the branched exhaust pipe 13 is connected to each cylinder 3. Further, in this exhaust pipe 13, the exhaust pipes 13 connected to the cylinder 3 included in the first bank 7 are gathered into one, and the exhaust pipes 13 connected to the cylinder 3 included in the second bank 8 are combined into one. Are gathered. Further, the exhaust pipe 13 has a downstream side in which the exhaust pipes 13 connected to the cylinders 3 included in the first bank 7 are gathered into one in the flow direction of the exhaust gas flowing in the exhaust pipe 13, and the second An O ₂ sensor 17 capable of detecting the amount of oxygen contained in the exhaust gas is provided on the downstream side where the exhaust pipes 13 connected to the cylinder 3 of the bank 8 are gathered together.

  The fuel property determination device 10 for the internal combustion engine 1 according to the first embodiment includes a fuel tank 20 that stores fuel to be supplied to the internal combustion engine 1. The fuel tank 20 includes an oil supply pipe 27 that is an oil supply passage that guides fuel to be supplied into the fuel tank 20. That is, the fuel supply pipe 27 is a passage through which fuel flows when fuel is supplied, has a tubular shape, one end is connected to the fuel tank, and the inside communicates with the fuel tank 20. An oil supply cap 28 that can open and close the oil supply pipe 27 is provided at the other end of the oil supply pipe 27. The fuel supply pipe 27 can supply fuel when the fuel supply cap 28 is opened. In addition, an open / close sensor 29, which is an open / close detection means formed so as to be able to detect whether the oil cap 28 is opened or closed, is provided in the vicinity of the oil cap 28 thus formed.

  The fuel tank 20 has a partition wall 23 on the inner side, and the fuel tank 20 is partitioned into a main tank 21 and a sub tank 22 by the partition wall 23. The partition wall 23 is formed so as to partition the main tank 21 and the sub tank 22 at least in the horizontal direction when the fuel tank 20 is in use.

  Further, the partition wall 23 is provided with a communication cutoff valve 25 that is a first communication cutoff means capable of switching between communication and cutoff between the main tank 21 and the sub tank 22. Specifically, a communication hole 24 is formed in the partition wall 23 at a position closer to the lower side in the fuel tank 20 when the fuel tank 20 is in use. The main tank 21 and the sub tank 22 are connected by the communication hole 24. Communicate. The communication shut-off valve 25 is provided in the communication hole 24 and is formed to be openable and closable. Therefore, when the communication cutoff valve 25 is opened, the main tank 21 and the sub tank 22 communicate with each other, and when the communication cutoff valve 25 is closed, the main tank 21 and the sub tank 22 are shut off.

  A fuel pump for sending fuel to the outside of the fuel tank 20 is provided in the main tank 21 and the sub tank 22, respectively. A main tank fuel pump 31 is provided in the main tank 21, and A sub tank fuel pump 32 is provided. Among these, the main tank fuel pump 31 is connected to a main fuel pipe 41 which is a main passage through which fuel in the main tank 21 passes. The main fuel pipe 41 is connected to an injector 12 provided in an intake pipe 11 connected to a cylinder group B that is a cylinder 3 included in the second bank 8. That is, the main fuel pipe 41 is formed to be able to supply the fuel in the main tank 21 to the cylinder group B.

  The sub tank fuel pump 32 is connected to a sub fuel pipe 42 which is a sub passage through which fuel in the sub tank 22 passes. The sub fuel pipe 42 is connected to an injector 12 provided in an intake pipe 11 connected to a cylinder group A that is a cylinder 3 of the first bank 7. That is, the sub fuel pipe 42 is formed so that the fuel in the sub tank 22 can be supplied to the cylinder group A.

  In addition, the main fuel pipe 41 and the sub fuel pipe 42 are connected to a connection fuel pipe 43 that communicates both. One end of the connection fuel pipe 43 is connected to the main fuel pipe 41, and the other end is connected to the sub fuel pipe 42. The main fuel pipe 41 and the connection fuel pipe 43, and the sub fuel pipe 42 and the connection fuel are connected. The pipes 43 communicate with each other inside. As a result, the main fuel pipe 41 and the sub fuel pipe 42 communicate with each other via the connection fuel pipe 43.

  Further, a fuel passage switching valve 45 that is a second communication blocking means capable of switching communication and blocking between the main fuel pipe 41 and the connection fuel pipe 43 is provided at a connection portion between the main fuel pipe 41 and the connection fuel pipe 43. Is provided. Since the fuel passage switching valve 45 is provided so as to be able to switch between communication and blocking between the main fuel pipe 41 and the connection fuel pipe 43 in this way, the fuel passage switching valve 45 is connected to the main fuel pipe 41 via the connection fuel pipe 43. The fuel pipe 41 and the sub fuel pipe 42 are formed so as to be able to switch between communication and blocking.

The injector 12, the air flow meter 16, the O ₂ sensor 17, the open / close sensor 29, the communication cutoff valve 25, and the fuel passage switching valve 45 that are provided as described above are all parts of a vehicle (not shown) on which the internal combustion engine 1 is mounted. Is connected to an ECU (Electronic Control Unit) 50 for controlling the control.

The ECU 50 is provided with a processing unit 51, a storage unit 59, and an input / output unit 60, which are connected to each other and can exchange signals with each other. The injector 12, the air flow meter 16, the O ₂ sensor 17, the open / close sensor 29, the communication cutoff valve 25, and the fuel passage switching valve 45 connected to the ECU 50 are connected to the input / output unit 60. 60 inputs / outputs signals to / from these sensors. The storage unit 59 stores a computer program for controlling the fuel property determination device 10 of the internal combustion engine 1 according to the present invention. The storage unit 59 is a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a RAM (Random Access Memory). A volatile memory or a combination thereof can be used.

  The processing unit 51 includes a memory and a CPU (Central Processing Unit), and at least a fuel supply determination unit 52 that is a fuel supply determination unit that determines whether the fuel tank 20 is supplied with fuel, and the fuel supply pipe 27. When fuel is supplied from the main tank 21, the communication cutoff valve 25 is shut off from the main tank 21 and the sub tank 22, and only the fuel stored in the sub tank 22 is supplied to the cylinder group A and the main cylinder group B is supplied to the cylinder group B. A supply fuel control unit 53 that is a supply fuel control unit that supplies only fuel stored in the tank 21 and a determination that is a fuel property determination condition establishment determination unit that determines whether a condition for performing fuel property determination is satisfied From the condition establishment determination unit 54, the fuel property determination control unit 55 that is a fuel property determination control unit that performs control for determining the fuel property, and the fuel supply pipe 27. A fuel property determination unit 56 that is a fuel property determination unit that performs fuel property determination in at least the cylinder group B when fuel is supplied, and a fuel property determination completion determination unit that determines whether the fuel property determination is completed. And a fuel property determination completion determination unit 57.

The control of the injector 12 and the fuel passage switching valve 45 included in the fuel property determination device 10 of the internal combustion engine 1 is performed by the processing unit 51 based on the detection result by the sensors such as the O ₂ sensor 17 provided in each part of the vehicle. The computer program is read and calculated in a memory incorporated in the processing unit 51, and control is performed by operating the injector 12 and the fuel passage switching valve 45 according to the result of the calculation. At that time, the processing unit 51 appropriately stores a numerical value in the middle of the calculation in the storage unit 59, and takes out the stored numerical value and executes the calculation. In addition, when controlling the fuel property determination apparatus 10 of the internal combustion engine 1 in this way, it may be controlled by dedicated hardware different from the ECU 50 instead of the computer program.

  The fuel property determination device 10 for the internal combustion engine 1 according to the first embodiment has the above-described configuration, and the operation thereof will be described below. When the internal combustion engine 1 is operated, air having a flow rate corresponding to the degree of opening and closing of the throttle valve 15 flows in the intake pipe 11 toward the cylinders 3 provided in the first bank 7 and the second bank 8. In the intake pipe 11, air flows in this way toward each cylinder 3, and the intake pipe 11 is provided with an injector 12 for each cylinder 3. The injector 12 is formed so that the fuel supplied from the fuel tank 20 can be injected into the intake pipe 11. For this reason, when the fuel is injected into the intake pipe 11 by the injector 12, the fuel and the air flowing through the intake pipe 11 are mixed to form an air-fuel mixture in which the fuel and air are mixed. In addition, since the injector 12 is provided for each cylinder 3, the air-fuel mixture produced by injecting fuel from the injector 12 is sucked into each cylinder 3. The air-fuel mixture sucked into the cylinder 3 burns fuel in the cylinder 3, and the internal combustion engine 1 is operated by the pressure at the time of combustion. The gas after the internal combustion engine 1 is operated and the fuel is combusted becomes exhaust gas and is discharged into the exhaust pipe 13.

  During operation of the internal combustion engine 1, the fuel in the fuel tank 20 is injected into the intake pipe 11 by the injector 12, and fuel is supplied to the injector 12 through the main fuel pipe 41 and the sub fuel pipe 42. Specifically, during normal operation of the internal combustion engine 1, the supply fuel control unit 53 included in the processing unit 51 of the ECU 50 opens the communication cutoff valve 25 included in the fuel tank 20 to connect the main tank 21 and the sub tank 22 to switch the fuel passage. The main fuel pipe 41 and the sub fuel pipe 42 are communicated by switching the valve 45.

  When the main tank fuel pump 31 and the sub tank fuel pump 32 of the fuel tank 20 are operated in this state, the fuel in the main tank 21 is supplied to the main fuel pipe 41 by the main tank fuel pump 31, and mainly the main fuel. Fuel is supplied to the cylinder 3 of the second bank 8, that is, the injector 12 of the cylinder group B through the pipe 41, and the fuel is supplied to the cylinder group B via the injector 12. The fuel in the sub tank 22 is supplied to the sub fuel pipe 42 by the sub tank fuel pump 32, and the fuel is mainly supplied to the cylinders 3 included in the first bank 7 through the sub fuel pipe 42, that is, the injectors 12 in the cylinder group A. Then, the fuel is supplied to the cylinder group A through the injector 12. Thereby, the internal combustion engine 1 can be operated by the fuel in the fuel tank 20.

  During the operation of the internal combustion engine 1, the fuel in the fuel tank 20 is supplied to the internal combustion engine 1 and used for the operation of the internal combustion engine 1 in this way. Therefore, the fuel in the fuel tank 20 is maintained by continuing the operation of the internal combustion engine 1. Will be less. Therefore, when the operation of the internal combustion engine 1 is further continued after the fuel in the fuel tank 20 is low, the fuel is supplied into the fuel tank 20. When fuel is supplied into the fuel tank 20, first, the fuel supply cap 28 provided at the tip of the fuel supply pipe 27 is opened, and fuel is supplied from the fuel supply pipe 27. At that time, an open / close sensor 29 provided in the vicinity of the fueling cap 28 detects that the fueling cap 28 has been opened. When it is detected by the open / close sensor 29 that the fuel supply cap 28 is opened, the supply fuel control unit 53 of the processing unit 51 of the ECU 50 closes the communication cutoff valve 25 to shut off the main tank 21 and the sub tank 22. The main fuel pipe 41 and the sub fuel pipe 42 are shut off by switching the fuel passage switching valve 45.

  Further, since the oil supply pipe 27 communicates with the main tank 21, if fuel is supplied in this state, the fuel is supplied only into the main tank 21. For this reason, in the main tank 21, the fuel before refueling and the newly refueled fuel are mixed. On the other hand, since the sub tank 22 is shut off from the main tank 21 by the communication shut-off valve 25, the fuel supplied from the fuel supply pipe 27 into the main tank 21 does not flow into the sub tank 22, but within the sub tank 22, Only the fuel before refueling is stored.

  When the internal combustion engine 1 is operated in this state, the fuel before refueling stored in the sub tank 22 is supplied to the cylinder group A which is the cylinder 3 of the first bank 7. For this reason, the cylinder group A is supplied with fuel having the same properties as the fuel used before fuel is newly supplied to the fuel tank 20, so that the cylinder group A is the same as before the fuel is supplied. It becomes a driving state. That is, when the new fuel is operated after refueling, the cylinder group A of the internal combustion engine 1 is in a stable operation state as before refueling.

  On the other hand, the cylinder group B, which is the cylinder 3 of the second bank 8, is supplied with fuel stored in the main tank 21, that is, fuel obtained by mixing fuel before refueling and newly refueled fuel. Is done. For this reason, in the cylinder group B, the fuel is operated by the mixed fuel. However, since the property of the newly refueled fuel is unknown, the property of the fuel obtained by mixing this fuel and the fuel before refueling is also unknown. It has become. Therefore, when operating the internal combustion engine 1 with this fuel, since the operating conditions suitable for this fuel are unknown, for example, the ideal air-fuel ratio is unknown, the cylinder group B is operated with this fuel, and this Determine the fuel properties of the fuel.

This determination is made from the cylinder group B by the O ₂ sensor 17 provided in the exhaust pipe 13 connected to the cylinder group B while adjusting the fuel injected from the injector 12 connected to the main fuel pipe 41. The amount of oxygen contained in the exhaust gas is detected. Thus, an air-fuel ratio suitable for this fuel is obtained, and the fuel property is determined by the fuel property determination unit 56 included in the processing unit 51 of the ECU 50. That is, the O ₂ sensor 17 while adjusting the fuel injected from the injector 12 to detect the amount of oxygen contained in exhaust gas discharged from the cylinder group B, and the value detected value predetermined by the O ₂ sensor 17 If so, the fuel property determination is completed.

  After the fuel property determination is completed, the supply fuel control unit 53 of the ECU 50 controls the communication shutoff valve 25 and the fuel passage switching valve 45 so that the main tank 21 and the sub tank 22 communicate with each other. The sub fuel pipe 42 is also communicated. Thereby, the fuel supplied into the main tank 21 flows into the sub tank 22, and the same property fuel is stored in the main tank 21 and the sub tank 22. The fuel in the sub tank 22 is supplied to the sub fuel pipe 42 by the sub tank fuel pump 32 and supplied to each cylinder of the cylinder group A from the injector 12 provided in the intake pipe 11 connected to the cylinder group A.

  Further, since the main fuel pipe 41 and the sub fuel pipe 42 communicate with each other, the fuel flowing in the main fuel pipe 41 and the fuel flowing in the sub fuel pipe 42 can flow to each other, so that the main tank 21 Both the fuel inside and the fuel inside the sub tank 22 can be supplied to the cylinder group A and the cylinder group B. The fuel in the fuel tank 20 can thus be supplied to both the cylinder group A and the cylinder group B. The fuel property of the fuel is determined by the fuel property determination unit 56. For this reason, the internal combustion engine 1 is brought into a stable operation state by performing the operation according to the fuel property in both the cylinder group A and the cylinder group B.

  FIG. 2 is a flowchart showing the processing procedure of the fuel property determination device for the internal combustion engine according to the first embodiment of the present invention. Next, the control method of the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment, that is, the processing procedure of the fuel property determination device 10 will be described in detail. In the processing procedure of the fuel property determination device 10, it is first determined whether the fuel tank 20 is being refueled (step ST101). In this determination, the open / close sensor 29 provided in the fuel tank 20 detects the state of the fuel supply cap 28, and the detection result is transmitted to the fuel supply determination unit 52 included in the processing unit 51 of the ECU 50. judge. That is, when refueling the fuel tank 20, the refueling cap 28 is opened and refueling is performed from the refueling pipe 27. When the refueling cap 28 is opened, fuel is refueled to the fuel tank 20. Can be determined. For this reason, when the open / close sensor 29 detects that the fuel supply cap 28 is opened, the fuel supply determination unit 52 determines that the fuel tank 20 is being supplied with fuel, and the fuel supply cap 28 is closed. Is detected by the open / close sensor 29, the fuel supply determination unit 52 determines that the fuel tank 20 is not fueled. If it is determined by this determination that the fuel tank 20 is not being refueled, the processing procedure is exited.

  If the fuel supply determination unit 52 determines that fuel is being supplied to the fuel tank 20, next, the main tank 21 to the sub tank 22 are shut off, and further, the main fuel pipe 41 to the sub fuel pipe 42 are connected. Shut off (step ST102). In this control, the supply fuel control unit 53 included in the processing unit 51 of the ECU 50 is configured to switch the fuel passage provided in the connection portion between the communication cutoff valve 25 provided in the fuel tank 20 and the main fuel pipe 41 and the connection fuel pipe 43. This is done by actuating the valve 45. That is, the supply fuel control unit 53 controls the communication cutoff valve 25 and the fuel passage switching valve 45 to shut off the main tank 21 and the sub tank 22 by closing the communication cutoff valve 25, and the fuel passage switching valve 45. By switching, the main fuel pipe 41 and the sub fuel pipe 42 are shut off. In this way, by closing the communication cutoff valve 25 and shutting off the main tank 21 and the sub-tank 22, the supplied fuel flows only into the main tank 21. For this reason, since the newly refueled fuel does not flow into the sub tank 22, the fuel before refueling, which is the fuel stored in the fuel tank 20 before refueling, is stored in the sub tank 22. . On the other hand, in the main tank 21, new fuel is stored that is a fuel obtained by mixing newly supplied fuel and fuel stored in the fuel tank 20 before refueling.

  The internal combustion engine 1 is controlled in a state in which the communication cutoff valve 25 and the fuel passage switching valve 45 are controlled by the supply fuel control unit 53 and the main tank 21 to the sub tank 22 and the main fuel pipe 41 to the sub fuel pipe 42 are shut off. When operated, the cylinder group A is operated with fuel before refueling, and the cylinder group B is operated with new fuel (step ST103). That is, the main tank 21 and the sub tank 22 are disconnected, and the main fuel pipe 41 and the sub fuel pipe 42 are disconnected, so that the cylinder group A to which the fuel in the sub tank 22 is supplied via the sub fuel pipe 42 is provided. Only the pre-fuel supply fuel that is stored in the sub tank 22 is supplied, and the cylinder group A operates with this pre-fuel supply fuel. Further, the main tank 21 and the sub tank 22 are shut off, and the main fuel pipe 41 and the sub fuel pipe 42 are shut off, whereby the cylinder group B to which the fuel in the main tank 21 is supplied via the main fuel pipe 41 is provided. Is supplied with only new fuel, which is fuel stored in the main tank 21, and the cylinder group B operates with this new fuel.

Next, in a state where the cylinder group A and the cylinder group B are operated with the fuel before refueling and the new fuel, it is determined whether the execution condition of the fuel property determination control is satisfied (step ST104). This determination is performed by the determination condition establishment determination unit 54 included in the processing unit 51 of the ECU 50. The execution condition of this fuel property determination control is a condition that allows the fuel property determination unit 56 of the processing unit 51 of the ECU 50 to execute control for determining the fuel property. Specifically, first, the O ₂ sensor 17 is operating normally, the oxygen concentration in the exhaust gas detected by the O ₂ sensor 17 during operation of the internal combustion engine 1 is transmitted to the ECU 50, and so-called feedback control can be performed. Determine whether Further, it is determined whether the temperature of the cooling water (not shown) for cooling the internal combustion engine 1 during the operation of the internal combustion engine 1 is equal to or higher than a predetermined temperature, thereby determining whether the warm-up operation is completed. judge. Further, it is determined whether the operation of the internal combustion engine 1 is stable.

The water temperature used for this determination is acquired directly from a water temperature detection sensor (not shown) of the internal combustion engine 1 or from information transmitted from the water temperature detection sensor to other parts in the ECU 50. Further, whether the operation of the internal combustion engine 1 is stable is determined based on the detection results by the air flow meter 16 and the O ₂ sensor 17, and feedback from these sensors changes very much during the processing procedure of the fuel property determination device 10. If the feedback is stable, it is determined that the operation of the internal combustion engine 1 is stable.

The determination condition establishment determination unit 54 performs these determinations, that the O ₂ sensor 17 operates normally and performs feedback control, that the water temperature is equal to or higher than a predetermined temperature, and that the operation of the internal combustion engine 1 is stable. Is satisfied, it is determined that the execution condition of the fuel property determination control is satisfied. If it is determined by this determination that the conditions for executing the fuel property determination control are not satisfied, the process returns to step ST103, the cylinder group A continues to operate with the fuel before refueling, and the cylinder group B continues to operate with the new fuel. .

If it is determined by the determination in the determination condition establishment determination unit 54 that the execution condition of the fuel property determination control is satisfied, then the fuel property determination control is executed in the cylinder group B (step ST105). In this fuel property determination control, the fuel property determination control unit 55 of the processing unit 51 of the ECU 50 changes the operation state of the cylinder group B and changes the property of the new fuel that is the fuel supplied to the cylinder group B. The determination is made by the fuel property determination unit 56 of the processing unit 51. Specifically, the fuel property determination control performed by the fuel property determination property control unit detects the amount of air flowing through the intake pipe 11 by the fuel property determination control unit 55 by the air flow meter 16 and supplies fuel to the cylinder group B. The O ₂ sensor 17 detects the amount of oxygen contained in the exhaust gas discharged from the cylinder group B while adjusting the amount of fuel injected from the injector 12.

In the fuel property determination control, the amount of oxygen contained in the exhaust gas is detected by the O ₂ sensor 17 while adjusting the fuel injection amount from the injector 12 as described above, and the fuel property determination unit 56 determines the fuel property. . At that time, when the fuel property determination unit 56 determines that the detected oxygen amount is large, the fuel injection amount from the injector 12 is increased, and when it is determined that the detected oxygen amount is small, the injector 12 Reduce the amount of fuel injection from By repeating this, the optimum air-fuel ratio in the case of burning new fuel that is the fuel supplied to the cylinder group B is obtained, and the fuel property is determined by the fuel property determination unit 56. During the fuel property determination control as described above, the cylinder group A is continuously supplied with the pre-fuel supply fuel stored in the sub tank 22, and the cylinder group A is supplied with the pre-fuel supply fuel. Continue driving.

  Next, it is determined whether the fuel property determination for the new fuel is completed (step ST106). This determination is performed by the fuel property determination completion determination unit 57 included in the processing unit 51 of the ECU 50, and when it is determined that the fuel property determination by the fuel property determination unit 56 is not completed, the process returns to step ST105, and the fuel property determination is performed. Continue judgment control.

  On the other hand, when the fuel property determination completion determination unit determines that the fuel property determination by the fuel property determination unit has been completed, the main tank 21 to the sub tank 22 are then communicated, and the main fuel pipe 41 is further connected. -The sub fuel piping 42 is connected (step ST107). In this control, the supply fuel control unit 53 of the ECU 50 controls the communication cutoff valve 25 and the fuel passage switching valve 45 to open the communication cutoff valve 25 so that the main tank 21 and the sub tank 22 communicate with each other and the fuel passage switching is performed. The main fuel pipe 41 and the sub fuel pipe 42 are communicated by switching the valve 45.

  As described above, the communication cutoff valve 25 is opened to allow the main tank 21 and the sub tank 22 to communicate with each other, so that the fuel in the main tank 21 also flows into the sub tank 22. That is, the fuel supplied to the fuel tank 20 also flows into the sub tank 22 via the main tank 21, and the fuel stored in the main tank 21 and the fuel stored in the sub tank 22 have the same properties. become. Further, the fuel stored in the main tank 21 can pass through the main fuel pipe 41 and the sub fuel by switching the fuel passage switching valve 45 to connect the main fuel pipe 41 and the sub fuel pipe 42. The fuel that can pass through the pipe 42 and that is stored in the sub tank 22 can pass through the sub fuel pipe 42 and the main fuel pipe 41. As a result, the cylinder group A and the cylinder group B are supplied with the same property fuel stored in the main tank 21 and operate with this fuel.

  In the fuel property determination device 10 for the internal combustion engine 1 described above, when the fuel is supplied from the fuel supply pipe 27 to the main tank 21, the main tank 21 and the sub tank 22 are shut off by the communication cutoff valve 25. The fuel is supplied only to the main tank 21, and only the fuel before refueling is stored in the sub tank 22. Further, when fuel is supplied from the fuel supply pipe 27, only the fuel stored in the sub tank 22 is supplied to the cylinder group A, and only the fuel stored in the main tank 21 is supplied to the cylinder group B. Supply. Thereby, in the cylinder group B, the property of the newly refueled fuel can be determined by burning the fuel in the main tank 21. Further, in the cylinder group A, the fuel property is already determined by burning the fuel in the sub tank 22, and the fuel can be operated with the fuel used for the operation of the internal combustion engine 1 before refueling. Can be obtained. Therefore, even when fuels having different fuel properties are supplied, accurate fuel property determination can be performed and controllability of the internal combustion engine 1 can be ensured. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  Further, a fuel passage switching valve 45 is provided that shuts off the main fuel pipe 41 and the sub fuel pipe 42 when fuel is supplied from the fuel supply pipe 27. For this reason, when fuel is supplied from the fuel supply pipe 27, the fuel passage switching valve 45 shuts off the main fuel pipe 41 and the sub fuel pipe 42, so that the cylinder group A can be more reliably supplied with before fueling. Is supplied from the sub tank 22 through the sub fuel pipe 42, and the cylinder group B is supplied with a new fuel, which is a mixture of the pre-fuel supply fuel and the newly supplied fuel. More reliably supplied from the main tank 21 via the main fuel pipe 41. As a result, it is possible to more reliably determine the property of the fuel newly supplied in the cylinder group B, and to burn the fuel used in the operation of the internal combustion engine 1 before the fuel supply in the cylinder group A. A stable operating state can be obtained. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  In addition, when the fuel property determination is completed, the main fuel pipe 41 and the sub fuel pipe 42 are communicated with the fuel passage switching valve 45, so that the fuel in the main tank 21 and the fuel in the sub tank 22 are transferred to the cylinder group. A and cylinder group B can be freely supplied as needed. Further, since the fuel supplied from the main tank 21 and the sub tank 22 is the fuel after the fuel property is determined, the internal combustion engine 1 is operated by burning this fuel in the cylinder group A and the cylinder group B. In this case, the operation according to the fuel property can be performed, and a stable operation state can be obtained more reliably. As a result, it is possible to improve the drivability when fuels having different properties are supplied to the internal combustion engine 1 more reliably.

  When the fuel property determination is completed, the main tank 21 and the sub-tank 22 are connected to the communication cutoff valve 25, so that the newly refueled fuel can be supplied to the sub-tank 22. The fuel and the fuel in the sub tank 22 have the same fuel properties. Therefore, the fuel in the sub-tank 22 and the fuel in the main tank 21 can be supplied to the cylinder group A and the cylinder group B with the same property, and these fuels are obtained after the property is determined. Since it is fuel, the cylinder group A and the cylinder group B can be operated according to the fuel properties. Thereby, the stable driving | running state can be obtained more reliably. As a result, it is possible to improve the drivability when fuels having different properties are supplied to the internal combustion engine 1 more reliably.

  The fuel property determination device 70 of the internal combustion engine 1 according to the second embodiment has substantially the same configuration as the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment, but a plurality of cylinder groups supplied from the main tank 21 are provided. It is characterized in that it is divided into two. Since other configurations are the same as those of the first embodiment, the description thereof is omitted and the same reference numerals are given. FIG. 3 is a schematic view of an internal combustion engine provided with an internal combustion engine fuel property determination apparatus according to Embodiment 2 of the present invention. The fuel property determination device 70 of the internal combustion engine 1 shown in the figure, like the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment, has a main tank 21 and a sub tank 22. A main tank fuel pump 31 is provided in the main tank 21, and a sub tank fuel pump 32 is provided in the sub tank 22. Of these, a sub fuel pipe 42 is connected to the sub tank fuel pump 32, and the sub fuel pipe 42 supplies fuel in the sub tank 22 to the injector 12 provided in the intake pipe 11 connected to the cylinder group A. It is provided so that it can be supplied.

  A main fuel pipe 71 is connected to the main tank fuel pump 31. Unlike the main fuel pipe 41 included in the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment, the main fuel pipe 71 is branched into a plurality of branches. A plurality of main fuel pipes 71 branched in the main fuel pipe 71 are branched main fuel pipes 72 that are a plurality of branch main passages. The main fuel pipe 71 is thus branched into a plurality and connected to the injector 12 provided in the intake pipe 11 connected to the cylinder 3 of the second bank 8. Further, the branched main fuel pipe 72 branches in two directions, and a cylinder group to which fuel is supplied by the injector 12 connected to one of the branched main fuel pipes 72 is a cylinder group B. A cylinder group to which fuel is supplied by the injector 12 connected to the other branched main fuel pipe 72 is a cylinder group C.

  Among the plurality of branch main fuel pipes 72 formed in this way, a branch part connection fuel pipe 73 that connects the branch main fuel pipe 72 and the sub fuel pipe 42 is connected to some of the branch main fuel pipes 72. Has been. The branch connection fuel pipe 73 has one end connected to the branch main fuel pipe 72 and the other end connected to the sub fuel pipe 42. The branch main fuel pipe 72, the branch connection fuel pipe 73, and the sub The fuel pipe 42 and the branch connection fuel pipe 73 communicate with each other inside. Thereby, the branch main fuel pipe 72 and the sub fuel pipe 42 communicate with each other via the branch connection fuel pipe 73.

  Further, the connection portion between the branch main fuel pipe 72 and the branch portion connection fuel pipe 73 is provided with a third communication cutoff means capable of switching between communication and cutoff between the branch main fuel pipe 72 and the branch portion connection fuel pipe 73. A certain branch passage switching valve 75 is provided. Since the branch passage switching valve 75 is provided so as to be able to switch between the communication between the branch main fuel pipe 72 and the branch portion connecting fuel pipe 73 in this way, the branch passage switching valve 75 is provided with the branch portion connecting fuel 75. The branch main fuel pipe 72 and the sub fuel pipe 42 are configured to be able to be switched between communication and blocking via the pipe 73. Further, the branch passage switching valve 75 is further connected to the injector 12 side portion of the branch main fuel pipe 72 via the main fuel pipe 71, more specifically, closer to the injector 12 side than the branch passage switching valve 75 in the branch main fuel pipe 72. The communication between the part and the main tank 21 can be switched and cut off.

  That is, when the branch passage switching valve 75 is switched to connect the branch main fuel pipe 72 and the branch portion connecting fuel pipe 73, the branch portion connecting fuel pipe 73 is located on the opposite side of the end on the branch passage switching valve 75 side. Since the positioned end is connected to the sub fuel pipe 42, the branch main fuel pipe 72 and the sub fuel pipe 42 communicate with each other through the branch connection fuel pipe 73. In this case, since the branch main fuel pipe 72 communicates only with the branch connection fuel pipe 73, the portion on the injector 12 side in the branch main fuel pipe 72 does not communicate with the main fuel pipe 71.

  For this reason, when the branch main fuel pipe 72 and the branch connection fuel pipe 73 are communicated, the portion on the injector 12 side of the branch main fuel pipe 72 connected to the injector 12 that supplies fuel to the cylinder group B is The main fuel pipe 71 connected to the main tank fuel pump 31 in the main tank 21 is disconnected. That is, the injector 12 side portion of the branched main fuel pipe 72 connected to the injector 12 that supplies fuel to the cylinder group B is disconnected from the main tank 21.

  When the branch passage switching valve 75 is switched to shut off the branch main fuel pipe 72 and the branch portion connection fuel pipe 73, the branch main fuel pipe 72 is connected to the branch portion connection fuel pipe 73. It is cut off from the pipe 42. In this case, the branch main fuel pipe 72, that is, the branch main fuel pipe 72 connected to the injector 12 that supplies fuel to the cylinder group B communicates with the main fuel pipe 71. The main tank 21 communicates with the main tank 21 through the main fuel pipe 71.

  Further, when the branch main fuel pipe 72 and the sub fuel pipe 42 are connected by connecting the branch main fuel pipe 72 and the branch portion connection fuel pipe 73 to each other, the branch passage switching valve 75 is further connected to the branch main fuel pipe 72. 72 and the main fuel pipe 71 are formed so as to communicate with each other. That is, the branch passage switching valve 75 communicates with the branch main fuel pipe 72 and the sub fuel pipe 42 and shuts off the main fuel pipe 71 from the main fuel pipe 71 and the portion of the branch main fuel pipe 72 on the injector 12 side. The branch main fuel pipe 72 and the main fuel pipe 71 and the branch main fuel pipe 72 and the main fuel pipe 71 are both connected to each other. It is formed to be switchable in three patterns of communicating.

  Further, the fuel property determination device 70 of the internal combustion engine 1 according to the second embodiment has an ECU 80 similarly to the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment, and the ECU 80 stores the processing unit 51 and the memory. The unit 59 and the input / output unit 60 are included. Among these, the processing unit 51 includes a fuel supply determination unit 52, a supply fuel control unit 53, a determination condition establishment determination unit 54, a fuel property determination control unit 55, a fuel property determination unit 56, and a fuel property determination completion determination unit. 57. Further, the processing unit 51 is a fuel correction determination unit that is a fuel correction determination unit that determines whether or not the fuel being subjected to fuel property determination in the fuel property determination control can be used after correcting the supply amount to the internal combustion engine 1. A portion 81 is provided.

  The fuel property determination device 70 for the internal combustion engine 1 according to the second embodiment is configured as described above, and the operation thereof will be described below. During normal operation when the internal combustion engine 1 is operated, the supply fuel control unit 53 included in the processing unit 51 of the ECU 80 opens the communication cutoff valve 25 included in the fuel tank 20 so that the main tank 21 and the sub tank 22 communicate with each other. The switching valve 45 is switched to allow the main fuel pipe 41 and the sub fuel pipe 42 to communicate with each other. Further, the supply fuel control unit 53 switches the branch passage switching valve 75 so that the branch main fuel pipe 72 and the sub fuel pipe 42 and the branch main fuel pipe 72 and the main fuel pipe 71 communicate with each other.

  When the main tank fuel pump 31 and the sub tank fuel pump 32 included in the fuel tank 20 are operated in this state, the fuel in the main tank 21 is supplied to the main fuel pipe 71 by the main tank fuel pump 31, and mainly the main fuel. The gas is supplied to the cylinder 3 of the second bank 8 through the pipe 71 and the branched main fuel pipe 72. That is, the fuel stored in the main tank 21 is supplied to the injectors 12 of the cylinder group B and the cylinder group C mainly through the main fuel pipe 71 and the branched main fuel pipe 72, and through these injectors 12. Supplied to cylinder group B and cylinder group C. Further, the fuel in the sub tank 22 is supplied to the sub fuel pipe 42 by the sub tank fuel pump 32, and is mainly supplied to the cylinder 3 of the first bank 7, that is, the injector 12 of the cylinder group A through the sub fuel pipe 42. The cylinder group A is supplied through the injector 12. Thereby, the internal combustion engine 1 can be operated by the fuel in the fuel tank 20.

  When the internal combustion engine 1 is operated, it is operated with the fuel in the fuel tank 20 in this way. Further, when the fuel in the fuel tank 20 is reduced by this operation and the fuel is supplied into the fuel tank 20, first, the fuel supply cap 28 provided at the tip of the fuel supply pipe 27 is opened, and the fuel is supplied from the fuel supply pipe 27. Refuel. At that time, an open / close sensor 29 provided in the vicinity of the fueling cap 28 detects that the fueling cap 28 has been opened. When it is detected that the fuel cap 28 has been opened, the fuel supply control unit 53 of the ECU 80 closes the communication cutoff valve 25 to shut off the main tank 21 and the sub tank 22 and switches the fuel passage switching valve 45. Thus, the main fuel pipe 71 and the sub fuel pipe 42 are shut off. Further, the supply fuel control unit 53 switches the branch passage switching valve 75 to cut off the branch main fuel pipe 72 and the sub fuel pipe 42 to make the branch main fuel pipe 72 and the main fuel pipe 71 communicate with each other.

  In this way, the main tank 21 and the sub tank 22 are shut off during refueling, so that the refueled fuel is refueled only in the main tank 21. Therefore, a new fuel that is a fuel in which a fuel before refueling and a newly refueled fuel are mixed is stored in the main tank 21, and a fuel before refueling that is a fuel before refueling is stored in the sub tank 22. Is stored. When the internal combustion engine 1 is operated in this state, the pre-refueling fuel stored in the sub tank 22 is supplied to the cylinder group A, which is the cylinder 3 of the first bank 7. For this reason, the cylinder group A is operated in a stable operation state as before refueling.

  On the other hand, the new fuel stored in the main tank 21 is supplied to the cylinder group B and the cylinder group C, which are the cylinders 3 included in the second bank 8. For this reason, the cylinder group B and the cylinder group C are operated with new fuel, but since the fuel newly supplied into the main tank 21 has unknown properties, this fuel and the fuel before refueling are mixed. The properties of new fuel, a new fuel, are also unknown. Therefore, when the internal combustion engine 1 is operated with this fuel, the cylinder group B and the cylinder group C are operated with the new fuel, and the fuel properties of the new fuel are determined.

This determination is made by adjusting the fuel injected from the injector 12 connected to the main fuel pipe 71 while the cylinder group is detected by the O ₂ sensor 17 provided in the exhaust pipe 13 connected to the cylinder group B and the cylinder group C. The amount of oxygen contained in the exhaust gas discharged from B and the cylinder group C is detected. Thus, an air-fuel ratio suitable for this fuel is obtained, and the fuel property is determined by the fuel property determination unit 56 of the ECU 80.

  FIG. 4 is a diagram showing the relationship between the mixing ratio of alcohol to gasoline and the injection increase ratio to gasoline. Note that the horizontal axis of FIG. 4 shows the mixing ratio of alcohol to gasoline, and shows that the ratio of alcohol increases from the left side to the right side in the figure. Further, the vertical axis in FIG. 4 indicates the ratio of increase in injection to the injection amount from the injector when the fuel is only gasoline, and indicates that the injection amount increases from the lower side to the upper side in the figure. . In the fuel property determination unit 56, the property of the new fuel is determined by the exhaust gas discharged from the cylinder group B and the cylinder group C as described above. When the property of the new fuel is determined, When the degree of change of the new fuel is within a predetermined range, it can be dealt with by correcting the injection amount from the injector 12. For example, when the fuel stored in the fuel tank 20 before refueling, that is, the fuel before refueling is gasoline and the fuel to be newly refueled is alcohol, by refueling the alcohol, gasoline and alcohol in the main tank 21 Is mixed.

  Here, since the theoretical air-fuel ratio of gasoline and alcohol is smaller than that of gasoline, when the alcohol is burned at the stoichiometric air-fuel ratio, the fuel from the injector 12 is larger than when gasoline is burned at the stoichiometric air-fuel ratio. It is necessary to increase the injection amount. For this reason, when gasoline and alcohol are mixed, it is necessary to increase the injection amount from the injector 12 as the ratio of alcohol to gasoline increases. Varies depending on the ratio.

  First, when alcohol is mixed with gasoline, if the amount of alcohol relative to gasoline is relatively small, the injection increase ratio relative to gasoline is increased by correction. That is, when alcohol is mixed with gasoline, when the fuel is increased from the gasoline alone and injected from the injector 12, if the injection increase ratio to gasoline is equal to or less than the upper limit correction amount 92, the correction is performed. Increase the injection amount. That is, the correction amount for the alcohol mixture ratio for gasoline and the injection increase ratio for gasoline, in other words, the correction amount for the mixture ratio of gasoline and alcohol can be shown by a correction amount line 91 (FIG. 4). Of these, the injection amount is increased by the correction in the portion of the upper limit correction amount 92 or less.

  On the other hand, when alcohol is mixed with gasoline, if the amount of alcohol relative to gasoline is relatively large, the number of cylinders 3 used for fuel property determination is reduced, and the number of cylinders 3 operated with fuel before refueling is increased. Fuel property determination control is performed. That is, when the fuel mixed with gasoline and alcohol is increased from the case of gasoline alone and injected from the injector 12, the fuel increase correction ratio with respect to gasoline becomes larger than the upper limit correction amount 92, so that fuel correction is impossible. In this case, the number of cylinders 3 used for determining the fuel properties is reduced, and the number of cylinders 3 operated with the fuel before refueling is increased. That is, in the correction amount line 91 indicating the correction amount with respect to the mixture ratio of gasoline and alcohol, in a portion exceeding the upper limit correction amount, the number of cylinders 3 used for fuel property determination is reduced and the number of cylinders 3 operated with fuel before fueling is increased. .

  Specifically, when the fuel correction enablement determination unit 81 included in the processing unit 51 of the ECU 80 determines that the fuel for which the fuel property determination is performed cannot be performed, the fuel supply control of the ECU 80 is performed. The unit 53 maintains the state of the communication cutoff valve 25 and the fuel passage switching valve 45 and switches only the branch passage switching valve 75. Thereby, the communication cutoff valve 25 maintains the state where the main tank 21 and the sub tank 22 are shut off, and the fuel passage switching valve 45 maintains the state where the main fuel pipe 71 and the sub fuel pipe 42 are shut off. On the other hand, the branch passage switching valve 75 communicates the branch main fuel pipe 72 and the sub fuel pipe 42 and switches the portion of the branch main fuel pipe 72 on the injector 12 side and the main fuel pipe 71 to be shut off.

  When the operation of the internal combustion engine 1 is continued in this state, the fuel before refueling stored in the sub tank 22 is supplied to the cylinder group A through the sub fuel pipe 42, and the branch portion connecting fuel pipe 73, the branch passage. It flows through the switching valve 75 to the cylinder group B side in the branched main fuel pipe 72 and is supplied to the cylinder group B.

  Further, the new fuel stored in the main tank 21 is blocked from flowing in the direction of the sub fuel pipe 42 by the fuel passage switching valve 45, and the main fuel pipe in the branch main fuel pipe 72 by the branch passage switching valve 75. The flow from the 71 side to the injector 12 that supplies fuel to the cylinder group B is blocked. Therefore, the new fuel stored in the main tank 21 is supplied only to the injector 12 that supplies fuel to the cylinder group C through the main fuel pipe 71. Accordingly, the cylinder group A and the cylinder group B can be operated with the fuel before refueling, and thus can be stably operated. In the cylinder group C, the fuel property of the new fuel supplied from the main tank 21 is continuously determined.

This fuel property determination is a fuel property determination in the case where it is determined that the fuel for which the fuel property determination is performed cannot perform the fuel correction, and therefore, the oxygen contained in the exhaust gas discharged from the cylinder group C While detecting the amount by the O ₂ sensor 17, the amount of fuel injected from the injector 12 that supplies fuel to the cylinder group C is adjusted. As a result, an air-fuel ratio in the vicinity of the stoichiometric air-fuel ratio of the new fuel is derived, and the reference injection amount of fuel injected from the injector 12 is changed so that the air-fuel ratio of the air-fuel mixture sucked by the cylinder group C is in the vicinity of the stoichiometric air-fuel ratio. To do.

  As described above, after the fuel property determination is performed in the cylinder group C, after the reference injection amount of the fuel injected from the injector 12 is changed, that is, after the determination of the fuel property is completed, the supply fuel control unit 53 of the ECU 80 By controlling the communication cutoff valve 25, the main tank 21 and the sub tank 22 are communicated. Thereby, the fuel supplied into the main tank 21 flows into the sub tank 22, and the same property fuel is stored in the main tank 21 and the sub tank 22. In addition, the supply fuel control unit 53 controls the fuel passage switching valve 45 and the branch passage switching valve 75 to further control the main fuel pipe 71 and the sub fuel pipe 42, the branch main fuel pipe 72 and the sub fuel pipe 42, and The branch main fuel pipe 72 and the main fuel pipe 71 are communicated.

  Thus, the fuel in the sub tank 22 supplied to the sub fuel pipe 42 by the sub tank fuel pump 32 is supplied to the cylinder group A through the sub fuel pipe 42, and the sub fuel pipe 42 and the branched main fuel pipe 72. Is supplied to the cylinder group B, and further supplied to the cylinder group C through the sub fuel pipe 42 and the main fuel pipe 71. Further, the fuel in the main tank 21 supplied to the main fuel pipe 71 by the main tank fuel pump 31 is supplied to the cylinder group C through the main fuel pipe 71, and the main fuel pipe 71 and the branched main fuel pipe. 72 is supplied to the cylinder group B, and further supplied to the cylinder group A through the main fuel pipe 71 and the sub fuel pipe 42.

  That is, the fuel in the main tank 21 and the fuel in the sub-tank 22 that have the same fuel property as the main tank 21 and the sub-tank 22 communicate with each other can be supplied to the cylinder group A, the cylinder group B, and the cylinder group C. Become. The fuel in the fuel tank 20 can be supplied to all the cylinders 3 of the cylinder group A, the cylinder group B, and the cylinder group C in this way, but the fuel property is determined by the fuel property determination unit 56. ing. For this reason, the internal combustion engine 1 is brought into a stable operation state by performing the operation according to the fuel property in all the cylinders 3.

  FIG. 5 is a flowchart showing a processing procedure of the fuel property determination device for an internal combustion engine according to the second embodiment of the present invention. Next, a control method of the fuel property determination device 70 of the internal combustion engine 1 according to the second embodiment, that is, a processing procedure of the fuel property determination device 70 will be described in detail. In the processing procedure of the fuel property determination device 70, first, it is determined whether the fuel tank 20 is being refueled (step ST201). In this determination, the open / close sensor 29 provided in the fuel tank 20 detects the state of the fuel supply cap 28, and the detection result is transmitted to the fuel supply determination unit 52 included in the processing unit 51 of the ECU 80. judge. If it is determined by this determination that the fuel tank 20 is not being refueled, the processing procedure is exited.

  If the fuel supply determination unit 52 determines that fuel is being supplied to the fuel tank 20, next, the main tank 21 to the sub tank 22 are shut off, and the main fuel pipe 71 to the sub fuel pipe 42 are shut off. . Further, the branch main fuel pipe 72 to the sub fuel pipe 42 are shut off, and the branch main fuel pipe 72 to the main fuel pipe 71 are communicated (step ST202). In this control, the supply fuel control unit 53 of the ECU 80 is divided into a communication cutoff valve 25 provided in the fuel tank 20, a fuel passage switching valve 45 provided in a connection portion between the main fuel pipe 71 and the connection fuel pipe 43, and a branch. This is performed by operating a branch passage switching valve 75 provided at a connection portion between the main fuel pipe 72 and the branch connection fuel pipe 73.

  That is, the main tank 21 and the sub tank 22 are shut off by closing the communication cutoff valve 25, and the main fuel pipe 71 and the sub fuel pipe 42 are shut off by switching the fuel passage switching valve 45. Further, the branch passage switching valve 75 is switched to cut off the branch main fuel pipe 72 and the branch portion connection fuel pipe 73 to cut off the branch main fuel pipe 72 and the sub fuel pipe 42. The main fuel pipe 71 communicates. Thus, by shutting off the main tank 21 and the sub tank 22, the supplied fuel flows only into the main tank 21, and therefore, in the sub tank 22, before refueling stored in the fuel tank 20 from before refueling. Fuel is stored. Further, in the main tank 21, a new fuel that is a fuel obtained by mixing a newly refueled fuel and a fuel stored in the fuel tank 20 before refueling is stored.

  The supply fuel control unit 53 controls the communication cutoff valve 25, the fuel passage switching valve 45, and the branch passage switching valve 75 to connect the main tank 21 to the sub tank 22, the main fuel pipe 71 to the sub fuel pipe 42, and the branch main fuel pipe. When the internal combustion engine 1 is operated in a state in which the connection between the sub-fuel pipes 72 and the sub fuel pipes 42 is disconnected and the branch main fuel pipes 72 and the main fuel pipes 71 communicate with each other, the cylinder group A is operated with fuel before refueling, and the cylinder groups B and C Group C operates with new fuel (step ST203). In other words, the main tank 21 and the sub tank 22 are shut off, and the main fuel pipe 71 and the sub fuel pipe 42 and the branch main fuel pipe 72 and the sub fuel pipe 42 are shut off, so that the sub tank 22 is connected via the sub fuel pipe 42. Only the pre-fuel supply fuel stored in the sub tank 22 is supplied to the cylinder group A to which the fuel is supplied, and the cylinder group A operates with this pre-fuel supply fuel. Further, the main fuel pipe 71 and the branch main fuel pipe 71 are connected to each other by shutting off the main tank 21 and the sub tank 22 and the main fuel pipe 71 and the sub fuel pipe 42 and communicating the branch main fuel pipe 72 and the main fuel pipe 71. 72, only the new fuel stored in the main tank 21 is supplied to the cylinder group B and the cylinder group C, to which the fuel in the main tank 21 is supplied, and the cylinder group B and the cylinder group C are Drive with this new fuel.

Next, it is determined whether the execution condition of the fuel property determination control is satisfied in a state where the cylinder group A is operated with the fuel before refueling and the cylinder group B and the cylinder group C are operated with the new fuel (step ST204). This determination is performed by the determination condition establishment determination unit 54 of the ECU 80. Whether the feedback control can be performed using the O ₂ sensor 17 in the same manner as the determination in the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment. It is determined whether the water temperature is equal to or higher than a predetermined temperature or whether the operation of the internal combustion engine 1 is stable. If it is determined by these determinations by the determination condition establishment determination unit 54 that the fuel property determination control execution condition is not satisfied, the process returns to step ST203, and the cylinder group A continues to operate with the fuel before refueling. B and C continue to operate with new fuel.

  If it is determined by the determination in the determination condition establishment determination unit 54 that the execution condition of the fuel property determination control is satisfied, then the fuel property determination control is executed in the cylinder group B and the cylinder group C ( Step ST205). In this fuel property determination control, the fuel property determination control unit 55 of the ECU 80 changes the operation state of the cylinder groups B and C and changes the property of the new fuel supplied to the cylinder groups B and C to the fuel property determination unit of the ECU 80. The determination is made at 56.

The fuel property determination control performed by the fuel property determination control unit 55 flows through the intake pipe 11 by the fuel property determination control unit 55 in the same manner as the fuel property determination control in the fuel property determination device 10 of the internal combustion engine 1 according to the first embodiment. The amount of oxygen contained in the exhaust gas discharged from the cylinder groups B and C is detected while the amount of air is detected by the air flow meter 16 and the fuel injection amount from the injector 12 that supplies fuel to the cylinder groups B and C is adjusted. , Detected by the O ₂ sensor 17. In the fuel property determination control, the optimum air-fuel ratio when the new fuel supplied to the cylinder groups B and C is burned is determined, and the fuel property determination unit 56 determines the fuel property. During the fuel property determination control as described above, the cylinder group A is continuously supplied with the pre-fuel supply fuel stored in the sub tank 22, and the cylinder group A is supplied with the pre-fuel supply fuel. Continue driving.

  Next, it is determined whether or not the new fuel whose fuel property is being determined can be corrected (step ST206). This determination is performed by the fuel correction possible determination unit 81 included in the processing unit 51 of the ECU 80. Specifically, the ratio of the supply amount to the supply amount of the fuel before refueling according to the mixing ratio of the new fuel, which is a fuel in which the fuel before refueling and the fuel that has been refueled are mixed, corrects this ratio. If the amount is less than or equal to the upper limit correction amount 92 (see FIG. 4), which is the upper limit when increasing or decreasing due to the above, it is determined that fuel correction is possible. In other words, as described above, as an example of the fuel, when the fuel before refueling is gasoline and the fuel to be newly refueled is alcohol, when alcohol is mixed with gasoline, it depends on the mixing ratio of alcohol to gasoline. When the injection increase ratio for gasoline is equal to or less than the upper limit correction amount 92, it is determined that fuel correction is possible. Note that the upper limit correction amount 92 that is a reference in making this determination is a storage unit 59 of the ECU 80 in advance as a limit correction amount when correcting the reference injection amount that is the reference injection amount of fuel injected from the injector 12. Is remembered.

  Next, it is determined whether the fuel property determination of the new fuel is completed (step ST207). This determination is performed by the fuel property determination completion determination unit 57 of the ECU 80, and when it is determined that the fuel property determination by the fuel property determination unit 56 is not completed, the process returns to step ST205 and the fuel property determination control is continued. .

  On the other hand, when the fuel property determination completion determination unit 57 determines that the fuel property determination by the fuel property determination unit 56 is completed, next, between the main tank 21 and the sub tank 22 and the main fuel pipes 71 to sub. The fuel pipes 42 communicate with each other. Further, the branch main fuel pipe 72 to the sub fuel pipe 42 and the branch main fuel pipe 72 to the main fuel pipe 71 are communicated (step ST208). This control is performed by the supply fuel control unit 53 of the ECU 80 controlling the communication cutoff valve 25, the fuel passage switching valve 45, and the branch passage switching valve 75.

  That is, the main tank 21 and the sub tank 22 are communicated by opening the communication cutoff valve 25, and the main fuel pipe 71 and the sub fuel pipe 42 are communicated by switching the fuel passage switching valve 45. Further, the branch passage switching valve 75 is switched to connect the branch main fuel pipe 72 and the branch portion connection fuel pipe 73 so that the branch main fuel pipe 72 and the sub fuel pipe 42 are connected. 72 and the main fuel pipe 71 communicate with each other. In this way, by connecting the main tank 21 and the sub tank 22, the fuel stored in the main tank 21 and the fuel stored in the sub tank 22 become the same property fuel. Further, the main fuel pipe 71 and the sub fuel pipe 42, the branch main fuel pipe 72 and the sub fuel pipe 42, and the branch main fuel pipe 72 and the main fuel pipe 71 are connected to each other in the main tank 21 and the sub tank 22. The stored fuel can pass through the main fuel pipe 71, the branch main fuel pipe 72, and the sub fuel pipe 42, respectively. As a result, the cylinder groups A, B, and C are supplied with the same property fuel stored in the main tank 21 and operate with this fuel.

  Further, when it is determined by the fuel correction enablement determination unit 81 of the ECU 80 whether the new fuel whose fuel property is being determined can be corrected (step ST206), it is determined that the fuel correction is impossible. The main tank 21 to the sub tank 22 and the main fuel pipe 71 to the sub fuel pipe 42 are shut off. Further, the branch main fuel pipe 72 to the sub fuel pipe 42 are communicated, and the branch main fuel pipe 72 to the main fuel pipe 71 are disconnected (step ST209). Specifically, when the fuel correction enablement determination unit 81 determines whether the new fuel can be corrected, the mixing of the new fuel, which is a fuel in which the fuel before refueling and the refueled fuel are mixed, is determined. When the ratio of the supply amount to the fuel supply amount before refueling according to the ratio is larger than the upper limit correction amount 92 (see FIG. 4), it is determined that fuel correction is impossible. That is, similarly to the above, when the fuel before refueling is gasoline as an example of fuel and the fuel to be newly refueled is alcohol, when alcohol is mixed with gasoline, it depends on the mixing ratio of alcohol to gasoline. If the injection increase ratio for gasoline is larger than the upper limit correction amount 92, it is determined that fuel correction is impossible.

  As described above, when it is determined by the fuel correction enablement determination unit 81 that the fuel correction of the new fuel for which the fuel property determination is performed is impossible, the supply fuel control unit 53 of the ECU 80 is connected to the communication cutoff valve 25. The fuel passage switching valve 45 and the branch passage switching valve 75 are controlled to communicate or block each part. That is, the main tank 21 and the sub tank 22 are shut off by closing the communication cutoff valve 25, and the main fuel pipe 71 and the sub fuel pipe 42 are shut off by switching the fuel passage switching valve 45. Further, by switching the branch passage switching valve 75 to connect the branch main fuel pipe 72 and the branch portion connection fuel pipe 73, the branch main fuel pipe 72 and the sub fuel pipe 42 are connected, while the branch main fuel pipe 72 is connected. The injector 12 side and the main fuel pipe 71 are disconnected from each other.

  The supply fuel control unit 53 controls the communication cutoff valve 25, the fuel passage switching valve 45, and the branch passage switching valve 75 to shut off the main tank 21 to the sub tank 22 and the main fuel pipe 71 to the sub fuel pipe 42 to branch. When the internal combustion engine 1 is operated in a state where the main fuel pipe 72 to the sub fuel pipe 42 communicate with each other and the branch main fuel pipe 72 to the main fuel pipe 71 are disconnected, the cylinder groups A and B operate with fuel before refueling, The cylinder group C operates with new fuel (step ST210). That is, the main fuel pipe 71 and the sub fuel pipe 42 are shut off in a state where the main tank 21 and the sub tank 22 are cut off, and the branch main fuel pipe 72 and the sub fuel pipe 42 are connected to each other. Is supplied to the cylinder group A through the sub fuel pipe 42 and supplied to the cylinder group B through the sub fuel pipe 42 and the branched main fuel pipe 72. Thereby, the cylinder groups A and B are supplied with the fuel before refueling stored in the sub tank 22, and the cylinder groups A and B are operated with the fuel before refueling. Further, the main fuel pipe 71 and the sub fuel pipe 42 are shut off while the main tank 21 and the sub tank 22 are shut off, and the main fuel pipe 71 and the main fuel pipe 71 are shut off from the branch main fuel pipe 72. The fuel in the tank 21 is supplied only to the cylinder group C through the main fuel pipe 71. As a result, the new fuel stored in the main tank 21 is supplied to the cylinder group C, and the cylinder group C is operated with this new fuel.

When it is determined that the fuel for determining the fuel property cannot be corrected, only the cylinder group C is operated with the new fuel in this way, and the fuel property determination control is executed in the cylinder group C ( Step ST211). In this fuel property determination control, the fuel property determination control unit 55 of the ECU 80 determines the property of the new fuel supplied to the cylinder group C by the fuel property determination unit 56 of the ECU 80 while changing the operating state of the cylinder group C. . That is, in this case, the fuel property determination control is performed by detecting the oxygen contained in the exhaust gas discharged from the cylinder group C operated by the new fuel that performs the fuel property determination by the O ₂ sensor 17 and supplying the fuel to the cylinder group C. The amount of fuel injected from the supplied injector 12 is adjusted.

  Thus, the fuel property determination control obtains an optimal air-fuel ratio when the new fuel supplied to the cylinder group C is burned, and the fuel property determination unit 56 determines the fuel property. Further, since this fuel property determination control is a fuel property determination control when it is determined that the fuel correction is impossible, when the optimum air-fuel ratio of the new fuel is obtained, the intake pipe 11 is supplied from the injector 12. The reference injection amount of the fuel to be injected from the injector 12 is changed so that the air-fuel ratio when the fuel is injected into the inside becomes this optimum air-fuel ratio. During the fuel property determination control, the cylinder groups A and B are continuously supplied with fuel before refueling, which is fuel stored in the sub tank 22, and the cylinder groups A and B Continue operation with fuel before refueling.

  Next, it is determined whether the fuel property determination of the new fuel is completed (step ST212). This determination is performed by the fuel property determination completion determination unit 57 of the ECU 80, and when it is determined that the fuel property determination by the fuel property determination unit 56 is not completed, the process returns to step ST211 and the fuel property determination control is continued. . In contrast, when the fuel property determination completion determination unit 57 determines that the fuel property determination by the fuel property determination unit 56 is completed, that is, after the fuel correction enablement determination unit 81 determines that fuel correction is impossible. When the fuel property determination completion determination unit 57 determines that the fuel property determination by the fuel property determination unit 56 is completed, the process proceeds to step ST208. Thereby, the main tank 21 and the sub tank 22 communicate with each other, and further communicate with the main fuel pipe 71 and the sub fuel pipe 42, the branch main fuel pipe 72 and the sub fuel pipe 42, and the branch main fuel pipe 72 and the main fuel pipe 71. . Therefore, the cylinder groups A, B, and C are supplied with fuel having the same property as the fuel that is stored in the main tank 21 and the fuel property determination is completed, and the fuel is operated with this fuel.

  The above-described fuel property determination device 70 for the internal combustion engine 1 determines that the fuel correction determination unit 81 determines that the fuel being determined cannot be used by correcting the supply amount to the internal combustion engine 1. The fuel property determination is performed from the cylinder groups B and C only in the cylinder group C, and the number of cylinders 3 that perform the fuel property determination is reduced. In other words, if the fuel being judged for fuel properties cannot be corrected, more time is spent to judge the fuel properties. Therefore, the number of cylinders 3 for which the fuel property judgment is performed is reduced, and the fuel before refueling. That is, the number of cylinders 3 operating with fuel before refueling is increased. As a result, the operating state of the internal combustion engine 1 during the fuel property determination can be more reliably stabilized, and the remaining cylinders 3 can be stabilized by increasing the number of cylinders 3 operated with the fuel before refueling to stabilize the operating state. Thus, the fuel property determination can be performed, and the fuel property determination can be performed more reliably. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  Further, by branching the main fuel pipe 71 into a plurality of branches to form a plurality of branch main fuel pipes 72 and further providing a branch passage switching valve 75, a part of the branch main fuel pipes 72 and It is possible to switch between communication and blocking with the sub fuel pipe 42 and communication and blocking between the branch main fuel pipe 72 and the main tank 21. As a result, when the number of cylinders 3 that perform fuel property determination is reduced during the fuel property determination, the branch passage switching valve 75 is switched to allow the branch main fuel pipe 72 and the sub fuel pipe 42 to communicate with each other. By shutting off the main fuel pipe 72 and the main tank 21, the fuel in the sub tank 22 can be supplied to the cylinder group B to which fuel is supplied from the branched main fuel pipe 72. For this reason, the number of cylinders 3 that can be operated with the fuel in the sub tank 22 can be increased. Therefore, when the fuel under fuel property determination cannot be corrected, it is possible to more reliably increase the number of cylinders 3 that are in a stable operation state by using the fuel in the sub tank 22 more reliably. The fuel property determination can be performed more reliably in the remaining cylinders 3 in the operated state. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  In the fuel property determination devices 10 and 70 of the internal combustion engine 1 described above, after determining the property of the fuel stored in the main tank 21, the main tank 21 and the sub tank 22 are communicated, and the cylinder group B and the cylinder group are connected. Although all the cylinders 3 are operated at the air-fuel ratio in the state where the fuel property is determined at C, the air-fuel ratio may be changed again when the main tank 21 and the sub tank 22 are communicated. That is, the fuel property determination is performed with the new fuel in the main tank 21. However, when a large amount of fuel before refueling remains in the sub tank 22 at the time of the fuel property determination, the main tank 21 and the sub tank 22 are connected to each other to connect the main tank. When the new fuel in 21 and the pre-fuel supply fuel in the sub-tank 22 are mixed, there is a possibility that the fuel property of the new fuel whose properties have been determined and the fuel property after mixing the new fuel and the pre-fuel supply fuel may change. In this case, since there is a possibility that the fuel cannot be supplied at an optimal air-fuel ratio, in such a case, the fuel property is determined according to the ratio of the new fuel in the main tank 21 and the fuel before refueling in the sub tank 22. It is desirable to change the air-fuel ratio determined by

  For this reason, in the fuel property determination unit 56, the fuel property determination is completed, the communication cutoff valve 25 communicates the main tank 21 and the sub tank 22, and the fuel passage switching valve 45 communicates with the main fuel pipes 41 and 71 and the sub fuel pipe 42. The fuel property may be further determined in accordance with the fuel in the main tank 21 and the fuel in the sub-tank 22 before communicating the main tank 21 and the sub-tank 22.

  Specifically, a storage amount detection sensor (not shown) for detecting the fuel storage amount is provided in both the main tank 21 and the sub tank 22, and the storage amount of new fuel in the main tank 21 and the fuel supply in the sub tank 22 are provided. The pre-fuel storage amount is detected, and the fuel property after mixing these fuels is determined by the fuel property determination unit 56 of the ECUs 50 and 80 according to the detected new fuel and pre-fuel supply storage amount. Accordingly, after the main tank 21 and the sub tank 22 are communicated, the fuel property determination can be performed according to the fuel in the main tank 21 and the fuel in the sub tank 22 before the main tank 21 and the sub tank 22 are communicated. Therefore, the property of the fuel used for the operation of the internal combustion engine 1 after refueling can be determined more accurately, and the internal combustion engine 1 can be operated stably. As a result, it is possible to more reliably achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  As another method for suppressing operation of the internal combustion engine 1 with a fuel having a property different from that of the fuel whose fuel property has been determined after the main tank 21 and the sub tank 22 are communicated with each other, after the fuel property determination has been performed. Alternatively, the main tank 21 and the sub tank 22 may be kept shut off until the fuel in the sub tank 22 runs out, and after the fuel in the sub tank 22 is consumed, the main tank 21 and the sub tank 22 may be communicated with each other. Thereby, after the communication between the main tank 21 and the sub tank 22, only the fuel whose fuel property is determined is supplied to each cylinder 3. Therefore, even after the communication between the main tank 21 and the sub tank 22, all the cylinders 3 are connected. Can be operated with the fuel whose fuel property is determined. As a result, it is possible to more reliably achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  The fuel property determination devices 10 and 70 of the internal combustion engine 1 described above are provided in the V-type internal combustion engine 1 having the first bank 7 and the second bank 8, but the fuel property determination devices 10 and 70 are provided. The internal combustion engine 1 provided may be other than the V-type internal combustion engine 1. The internal combustion engine 1 provided with the fuel property determination devices 10 and 70 has a plurality of cylinders 3, and the cylinder 3 and the sub tank 22 that can supply fuel only from the main tank 21 by switching the fuel passage switching valve 45. It is only necessary to have the cylinder 3 that can supply fuel only from the cylinder. Thus, when determining the fuel properties, the internal combustion engine 1 is stabilized by the cylinder 3 supplied only from the sub tank 22 while the fuel is determined by the cylinder 3 supplied only from the main tank 21. And can drive. As a result, it is possible to achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  In the fuel property determination devices 10 and 70 of the internal combustion engine 1 described above, the main tank 21 and the sub tank 22 are divided into the main tank 21 and the sub tank 22 by providing a partition wall 23 in one fuel tank 20. However, the main tank 21 and the sub tank 22 may be provided independently. Even when the main tank 21 and the sub-tank 22 are provided independently, the main tank 21 and the sub-tank 22 communicate with each other, and a communication shut-off valve 25 that can switch between communication and shut-off between the main tank 21 and the sub-tank 22 is provided. What is necessary is just to be provided. Thereby, the main tank 21 and the sub tank 22 are shut off during the fuel property determination in the main tank 21, so that the fuel in the sub tank 22 whose properties are known during the fuel property determination in the main tank 21 The internal combustion engine can be operated stably.

  Further, in the internal combustion engine 1 provided with the fuel property determination devices 10 and 70 of the internal combustion engine 1 described above, the injector 12 is provided in the intake pipe 11, and port injection is performed to inject fuel into the intake pipe 11 when fuel is supplied. Although the internal combustion engine 1 supplies fuel into the cylinder 3, the injector 12 may be provided directly in the cylinder 3. In other words, the internal combustion engine 1 may be an internal combustion engine 1 that supplies fuel by so-called in-cylinder injection, in which fuel is injected into the cylinder 3 from the injector 12. The injector 12 that injects the fuel may be provided so that the fuel supplied into the cylinder 3 during the fuel property determination control can be arbitrarily switched between the fuel in the main tank 21 and the fuel in the sub tank 22. As long as it is provided, the form of fuel supply is not limited.

  Further, in the fuel property determination device 10 for the internal combustion engine 1 according to the first embodiment, a fuel passage switching valve 45 capable of switching between communication and cutoff between the main fuel pipe 41 and the sub fuel pipe 42 is provided. The fuel supplied to the cylinder group A and the cylinder group B is controlled by switching the fuel passage switching valve 45, but these may be controlled by other means. For example, a fuel passage for supplying fuel to the cylinder group A and a fuel passage for supplying fuel to the cylinder group B are independently connected to both the main tank 21 and the sub tank 22 to supply fuel from both sides. Further, there is provided a switching means capable of switching between communication between the portion communicating with the main tank 21 and the portion communicating with the sub tank 22 in both fuel passages. This switching means is controlled by the supply fuel control unit 53 of the ECU. As a result, it is possible to create a state in which the cylinder group A is supplied with fuel only from the sub tank 22 and the cylinder group B is supplied with fuel only from the main tank 21, so that the cylinder group A is operated with fuel before refueling. In the cylinder group B, the property of the new fuel can be determined.

  In other words, when the fuel is supplied to the fuel tank 20, the fuel in the sub tank 22 is supplied only to the cylinder group A, and the fuel in the main tank 21 is supplied only to the cylinder group B. That's fine. As a result, the cylinder group A can operate with the pre-fuel supply fuel while refueling, and the cylinder group B can determine the property of the new fuel. Therefore, the stable operation state of the internal combustion engine 1 can be determined while determining the fuel property. Obtainable. Such a configuration is the same in the fuel property determination device 70 for the internal combustion engine 1 according to the second embodiment.

  Furthermore, in the fuel property determination device 70 for the internal combustion engine 1 according to the second embodiment, the main fuel pipe 71 is branched and a branch passage switching valve 75 is provided, and the number of cylinders 3 that supply fuel from the main fuel pipe 71 is required. However, the number of cylinders 3 that supply fuel from the main fuel pipe 71 may be changed by other means. For example, as in the case where the passage for supplying fuel to the cylinder group A and the passage for supplying fuel to the cylinder group B are independently communicated with both the main tank 21 and the sub tank 22, a predetermined cylinder is used. A fuel passage for supplying fuel to the group is communicated with both the main tank 21 and the sub tank 22 independently. Further, in these fuel passages, there is provided switching means capable of switching between communication and blocking between a portion communicating with the main tank 21 and a portion communicating with the sub tank 22. As a result, fuel can be arbitrarily supplied from the main tank 21 and the sub tank 22 for each cylinder group, so that the number of cylinders 3 performing the fuel property is changed depending on whether or not the fuel whose property is being judged can be corrected. In some cases, it can be easily changed.

  Further, in the fuel property determination device 70 of the internal combustion engine 1 according to the second embodiment, the fuel property determination is performed by the cylinder group B and the cylinder group C, and when the fuel during the fuel property determination cannot be corrected, the cylinder group C Only the fuel property is done. That is, in the fuel property determination device 70 of the internal combustion engine 1 according to the second embodiment, the fuel property determination is performed in two stages when the fuel correction is impossible. The fuel property determination may be performed by other than the above. For example, in addition to the cylinder groups A, B, and C, the cylinder group D is provided. At first, while the cylinder group A is operated with the fuel before refueling, fuel property determination control is performed on the cylinder groups B, C, and D, and the fuel property is being determined. When it is determined that the fuel cannot be corrected, the cylinder groups A and B operate with the fuel before refueling, and the cylinder groups C and D perform fuel property determination control. Further, when it is difficult to determine the fuel property in the fuel property determination control by the cylinder groups C and D and it takes time to complete the fuel property determination, the cylinder group C is supplied with the pre-fuel supply fuel to the cylinder group C. The operation is performed with the fuel before refueling, and only the cylinder group D performs the fuel property determination control.

  This makes it possible to increase the number of cylinders 3 that are operated with fuel before fueling, that is, with fuel whose fuel properties are known, even when fuel whose characteristics are difficult to determine due to the fact that its properties differ greatly from the fuel before fueling. it can. Therefore, the internal combustion engine 1 can be stably operated, and the fuel property determination can be performed in a state where the internal combustion engine 1 is stably operated as described above. As a result, it is possible to more reliably achieve both drivability and fuel property determination when fuels having different properties are supplied to the internal combustion engine 1.

  As described above, the fuel property determination device for an internal combustion engine according to the present invention is useful for an internal combustion engine that can be operated with fuel having different properties, and is particularly suitable for a case where the internal combustion engine has a plurality of cylinders. Yes.

1 is a schematic diagram of an internal combustion engine provided with a fuel property determination device for an internal combustion engine according to Embodiment 1 of the present invention. It is a flowchart which shows the process sequence of the fuel property determination apparatus of the internal combustion engine which concerns on Example 1 of this invention. It is the schematic of the internal combustion engine provided with the fuel-properties determination apparatus of the internal combustion engine which concerns on Example 2 of this invention. It is a figure which shows the relationship between the mixing ratio of the alcohol with respect to gasoline, and the injection increase ratio with respect to gasoline. It is a flowchart which shows the process sequence of the fuel property determination apparatus of the internal combustion engine which concerns on Example 2 of this invention.

Explanation of symbols

1 engine 3 cylinder 6 bank7 first bank 8 second bank 10, 70 fuel property determination device 11 intake pipe 12 injector 13 exhaust pipe 15 throttle valve 16 flow meter 17 O ₂ sensor 20 fuel tank 21 main tank 22 sub-tank 23 bulkhead 24 communication hole 25 communication cutoff valve 27 oil supply pipe 28 oil supply cap 29 open / close sensor 31 main tank fuel pump 32 sub tank fuel pump 41, 71 main fuel pipe 42 sub fuel pipe 43 connection fuel pipe 45 fuel passage switching valve 50, 80 ECU
DESCRIPTION OF SYMBOLS 51 Processing part 52 Fuel supply determination part 53 Supply fuel control part 54 Determination condition establishment determination part 55 Fuel property determination control part 56 Fuel property determination part 57 Fuel property determination completion determination part 59 Storage part 60 Input / output part 72 Branch main fuel piping 73 Branch Connection fuel piping 75 branch passage switching valve 81 fuel correction possible determination unit 91 correction amount line 92 upper limit correction amount

Claims (7)

A main tank communicating with a fuel supply passage that is a passage through which the fuel passes when fueling an internal combustion engine having a plurality of cylinders;
A sub-tank communicating with the main tank;
First communication blocking means capable of switching communication and blocking between the main tank and the sub tank;
A sub-passage capable of supplying at least the fuel stored in the sub-tank to a first cylinder group that is a part of the plurality of cylinders;
A main passage capable of supplying at least the fuel stored in the main tank to a second cylinder group that is the cylinder other than the first cylinder group among the plurality of cylinders;
When the fuel is supplied from the oil supply passage, the first communication blocking means blocks the main tank and the sub tank, and only the fuel stored in the sub tank in the first cylinder group is stored. And supply fuel control means for supplying only the fuel stored in the main tank to the second cylinder group,
Fuel property determining means for determining a fuel property at least in the second cylinder group when the fuel is supplied from the fuel supply passage;
A fuel property determination apparatus for an internal combustion engine, comprising: The main passage and the sub passage communicate with each other, and are connected via a second communication blocking means capable of switching between communication and blocking between the main passage and the sub passage,
2. The fuel supply control unit according to claim 1, wherein when the fuel is supplied from the fuel supply passage, the fuel supply control unit causes the second communication cutoff unit to shut off the main passage and the sub passage. A fuel property determination device for an internal combustion engine.   3. The fuel supply control unit according to claim 2, wherein when the fuel property determination by the fuel property determination unit is completed, the supply fuel control unit causes the second communication cutoff unit to communicate the main passage and the sub passage. An internal combustion engine fuel property determination device.   The said supply fuel control means makes the said main tank and the said sub tank communicate with the said 1st communication interruption | blocking means, when the said fuel property determination by the said fuel property determination means is completed. The fuel property determination apparatus for an internal combustion engine according to any one of the preceding claims.   The fuel property determining means is provided in the main tank before the main tank and the sub tank are communicated after the fuel property determination is completed and the first communication blocking means communicates the main tank and the sub tank. 5. The fuel property determination apparatus for an internal combustion engine according to claim 4, wherein fuel property determination is further performed according to the fuel and the fuel in the sub tank. The fuel property determination means further comprises a fuel correction determination means for determining whether or not the fuel being determined can be used by correcting the supply amount to the internal combustion engine,
The fuel property determining means reduces the number of cylinders that perform the fuel property determination when the fuel correction determining means determines that the fuel supply amount cannot be used after correcting. The fuel property determination device for an internal combustion engine according to any one of 1 to 5. The main passage is divided into a plurality of branches, and the plurality of branched main passages become a plurality of branch main passages and communicate with the sub passages, respectively.
Among the plurality of branch main passages, a part of the branch main passages can be switched between communication and cutoff between the branch main passage and the sub passage, and communication and cutoff between the branch main passage and the main tank. It is connected to 3 communication blocking means,
The fuel supply control means causes the third communication cutoff means to communicate the branch main passage and the sub passage when the fuel property determination means reduces the number of cylinders for which the fuel property determination is performed, and the branch 7. The fuel property determination apparatus for an internal combustion engine according to claim 6, wherein a main passage and the main tank are shut off.

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