JP2018131920A - Evaporative fuel treatment device and method for determining state of evaporative fuel treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a connection state between piping for supplying evaporative fuel and an intake pipe.SOLUTION: An evaporative fuel treatment device includes an intake pipe, a canister, a purge passage through which purge gas passes and an atmosphere passage. A supercharger is provided in the intake pipe. A first valve is provided on the upstream side of the supercharger in the intake pipe. A second valve is provided on the downstream side of the supercharger in the intake pipe. The canister sucks evaporative fuel evaporated in a fuel tank. The purge passage is connected to the intake pipe between the first valve and the supercharger. A third valve and a pump are provided in the purge passage. The third valve controls purge gas supply amount to the intake pipe. The pump is provided between the canister and the third valve. The atmosphere passage is connected to the canister and has one end opened to the atmosphere. A fourth valve for controlling an opening of the atmosphere passage is provided in the atmosphere passage.SELECTED DRAWING: Figure 1

Description

  The present specification relates to a fuel vapor processing apparatus. The present specification also relates to a method for determining the state of the evaporated fuel processing apparatus, particularly the connection state between the intake pipe and the purge passage.

  Patent Document 1 discloses an internal combustion engine system provided with a supercharger. In the internal combustion engine system of Patent Document 1, valves are provided in the intake pipe both upstream and downstream of the supercharger. Patent Document 1 improves the responsiveness of the supercharger by changing the opening timing of the upstream valve and the downstream valve of the supercharger.

Japanese Patent Application Laid-Open No. 11-229884

  In order to prevent the evaporated fuel generated in the fuel tank from being released into the atmosphere, the evaporated fuel may be supplied into the intake pipe and processed by the internal combustion engine. In this case, a pipe for supplying evaporated fuel is connected to the intake pipe. When the pipe is removed from the intake pipe, the evaporated fuel is released to the atmosphere. Therefore, it is necessary to determine whether or not the pipe is connected to the intake pipe. The present specification discloses an evaporated fuel processing apparatus capable of determining a connection state between a pipe for supplying evaporated fuel and an intake pipe.

  An evaporative fuel processing apparatus disclosed in the present specification is connected to an intake pipe, a canister, and an intake pipe, a purge passage through which purge gas sent from the canister to the internal combustion engine passes, and an atmospheric passage connected to the canister May be provided. The air supplied to the internal combustion engine may pass through the intake pipe. The intake pipe may be provided with a supercharger. The intake pipe may be provided with a first valve that controls the amount of air supplied to the supercharger upstream of the supercharger. Further, the intake pipe may be provided with a second valve for controlling the intake amount of the internal combustion engine on the downstream side of the supercharger. The canister may adsorb the evaporated fuel evaporated in the fuel tank. The purge passage may be connected to the intake pipe between the first valve and the supercharger. A third valve and a pump may be provided in the purge passage. The third valve may control the amount of purge gas supplied to the intake pipe. The pump is provided between the canister and the third valve, and the purge gas may be sent into the intake pipe. The atmospheric passage is connected to the canister, and one end may be open to the atmosphere. The atmospheric passage may be provided with a fourth valve that controls the opening degree of the atmospheric passage.

  The evaporative combustion processing apparatus is provided with a first valve upstream of the supercharger, and a purge passage is connected between the first valve and the supercharger. By providing the first valve upstream of the supercharger, the pressure in the intake pipe at the portion (between the first valve and the supercharger) to which the purge passage is connected can be changed. In other words, the evaporative combustion processing apparatus can change the pressure in the space (in the intake pipe between the first valve and the supercharger) to which purge gas is supplied from the purge passage. The evaporative combustion processing apparatus is provided with a third valve and a pump in the purge passage and a fourth valve in the atmospheric passage. When the third valve is opened and the fourth valve is closed and the pump is driven in the forward rotation, the purge gas can be supplied into the intake pipe with the upstream side of the purge passage closed. Alternatively, when the third valve is opened and the fourth valve is closed and the pump is driven in reverse rotation, the purge gas can be confined in the upstream of the pump (purge passage, atmospheric passage) with the upstream of the purge passage closed. it can. Note that “driving the pump in the forward rotation” means driving the pump so as to send the gas toward the intake pipe. Further, “driving the pump in reverse rotation” means driving the pump so as to send the gas toward the canister.

  Regardless of whether the pump is driven forward or reverse, the pressure between the first valve and the supercharger (hereinafter referred to as pressure P1) is low if the purge passage is normally connected to the intake pipe. The lower the pressure upstream of the pump (hereinafter referred to as pressure P2). For example, the pressure P2 when the pressure P1 is negative (gauge pressure) is lower than the pressure P2 when the pressure P1 is atmospheric pressure. Further, when the purge passage is disengaged from the intake pipe, the end of the purge passage on the intake pipe side is opened to the atmosphere. Therefore, when the pump is driven with the purge passage removed from the intake pipe, even if the pressure P1 is a negative pressure, the pressure P2 shows the same value (a value larger than the original value) when the pressure P1 is atmospheric pressure. The evaporative combustion processing apparatus has a structure for changing the pressure (pressure P1) in the intake pipe at a portion to which the purge passage is connected and a structure for driving the pump in a state where the upstream of the purge passage is closed. It can be determined whether (pipe) is connected to the intake pipe.

  The present specification also discloses a method for determining the connection state between the intake pipe and the purge passage in the above-described evaporated fuel processing apparatus. The determination method is as follows: the third valve is opened, the fourth valve is closed, the pump is driven, the pressure P1 in the intake pipe between the first valve and the supercharger, and between the pump and the fourth valve. The pressure P2 in the passage may be detected. In this determination method, by comparing a detected pressure difference between the pressure P1 and the pressure P2 with a determination value based on a pressure difference between the pressure P1 and the pressure P2 when the intake pipe and the purge passage are connected, A connection state between the pipe and the purge passage may be determined. The “passage between the pump and the fourth valve” includes both the purge passage and the atmospheric passage.

1 shows an outline of a fuel vapor processing apparatus according to a first embodiment. The outline of the evaporative fuel processing apparatus of 2nd Example is shown. The figure for demonstrating the 1st determination method is shown. The flowchart of a 1st determination method is shown. The figure for demonstrating the 2nd determination method is shown. The flowchart of the 2nd determination method is shown. The figure for demonstrating the 3rd determination method is shown. The flowchart of the 3rd determination method is shown. The figure for demonstrating the 4th determination method is shown. The flowchart of the 4th determination method is shown. The flowchart of the 5th determination method is shown.

  The technical features disclosed in this specification are listed below. Note that the technical elements described below are independent technical elements, and exhibit technical usefulness alone or in various combinations.

  An evaporative fuel processing apparatus disclosed in the present specification is connected to an intake pipe, a canister, and an intake pipe, a purge passage through which purge gas sent from the canister to the internal combustion engine passes, and an atmospheric passage connected to the canister May be provided. Air supplied to the internal combustion engine may pass through the intake pipe. The intake pipe may be provided with a supercharger. The intake pipe may be provided with a first valve that controls the amount of air supplied to the supercharger upstream of the supercharger. Further, the intake pipe may be provided with a second valve for controlling the intake amount of the internal combustion engine on the downstream side of the supercharger. The canister may adsorb the evaporated fuel evaporated in the fuel tank. The purge passage may be connected to the intake pipe between the first valve and the supercharger. A third valve and a pump may be provided in the purge passage. The third valve may control the amount of purge gas supplied to the intake pipe. The pump is provided between the canister and the third valve, and the purge gas may be sent into the intake pipe. The atmospheric passage is connected to the canister, and one end may be open to the atmosphere. The atmospheric passage may be provided with a fourth valve that controls the opening degree of the atmospheric passage. This fuel vapor processing apparatus can determine whether or not the purge passage is connected to the intake pipe by controlling the valves (first to fourth valves) and the pump in a specific state.

  A first pressure gauge for detecting the pressure in the intake pipe may be provided between the first valve and the supercharger. Moreover, the 2nd pressure gauge which detects the pressure in a channel | path may be provided between the pump and the 4th valve. Whether the purge passage is connected to the intake pipe can be determined using the value of the first pressure gauge and the value of the second pressure gauge. The second pressure gauge may be provided in a passage (purge passage) between the pump and the canister, or may be provided in a passage (atmospheric passage) between the canister and the fourth valve. The fuel vapor processing apparatus controls the states of the third valve, the fourth valve, and the pump, and determines the connection state between the intake pipe and the purge passage based on the detection values of the first pressure gauge and the second pressure gauge. A determination unit may be provided.

  The pump may be of a type that can switch between forward and reverse rotation. When the purge gas is supplied to the intake pipe, the pump can be driven in the forward direction, and when determining the connection state between the intake pipe and the purge passage, the pump can be driven in the reverse direction. By driving the pump in the reverse rotation, it is possible to determine the connection state between the intake pipe and the purge passage without supplying purge gas to the intake pipe, thereby suppressing the influence on the air-fuel ratio of the internal combustion engine. it can.

  The above-described method for determining the connection state between the intake pipe and the purge passage in the fuel vapor processing apparatus may be carried out with the third valve open, the fourth valve closed, and the pump driven. As a result, gas is discharged from the purge passage to the intake pipe side or the gas is introduced into the purge passage from the intake pipe side of the purge passage in a state where the purge passage and the outside air are prohibited from communicating via the atmospheric passage. be able to. In the above determination method, the pressure P1 in the intake pipe between the first valve and the supercharger and the pressure P2 in the passage between the pump and the fourth valve are detected, and the differential pressure between the detected pressure P1 and pressure P2 is detected. (Detected differential pressure) and a connection value between the intake pipe and the purge passage by comparing a determination value based on a differential pressure (reference differential pressure) between the pressure P1 and the pressure P2 when the intake pipe and the purge passage are connected. May be determined. As long as the pressure P2 is detected between the pump and the fourth valve, the pressure P2 may be detected in either the purge path from the pump to the canister or the atmospheric path from the canister to the fourth valve.

  Further, the determination value may be a specified value created in advance for each corresponding pressure P1. In this case, the determination value for the pressure P1 may be stored in a control circuit or the like. Alternatively, the determination value may be a value created based on the measured value of the pressure P1. In this case, a function for creating the determination value may be stored in the control circuit or the like.

  In the above determination method, the pump may be driven by normal rotation (control for discharging gas from the pump toward the intake pipe), or the pump may be rotated in reverse (control for discharging gas from the pump toward the fourth valve). It may be driven by. When the pump is driven in reverse rotation, when the purge passage is normally connected to the intake pipe, it is possible to suppress introduction of excessive purge gas (unnecessary for determination) into the intake pipe. The connection state between the intake pipe and the purge passage can be determined without affecting the air-fuel ratio of the internal combustion engine. Further, when the pump is driven in reverse rotation, it is possible to determine the connection state between the intake pipe and the purge passage without releasing the purge gas to the atmosphere when the purge passage is detached from the intake pipe.

  In the above determination method, the determination criterion for the determination value may be different depending on the rotation direction of the pump and the value of the pressure P1. That is, it is determined that an abnormality has occurred (the purge passage is out of the intake pipe) when the pressure difference between the pressures P1 and P2 (detected differential pressure) is greater than or equal to the determination value, depending on the rotation direction of the pump and the pressure P1. In some cases, it is determined that an abnormality has occurred when the differential pressure is equal to or lower than a determination value.

  When the pump is driven in the positive rotation when the pressure P1 is negative, the value of the pressure P2 is lower than the pressure before driving the pump (atmospheric pressure P0). In this case, when the purge passage is separated from the intake pipe, the end of the purge passage is opened to the atmosphere having a pressure higher than the pressure P1, so that the pressure is lower than when the purge passage is normally connected to the intake pipe. The amount of change in P2 becomes small. That is, when the pump is driven at a positive rotation when the pressure P1 is negative, if the purge passage is disconnected from the intake pipe (an abnormality has occurred), the purge passage is normally connected to the intake pipe. The differential pressure ΔP is smaller than the differential pressure ΔP. Therefore, the differential pressure ΔP (P1−P2) created from the detected pressures P1 and P2 is compared with the determination value α1, and in the case of (ΔP ≦ α1), it is determined that the purge passage is disconnected from the intake pipe. Can do. The determination value α1 may be smaller than the differential pressure (reference differential pressure) when the purge passage is normally connected to the intake pipe. For example, the determination value α1 may be 2 to 4 kPa smaller than the differential pressure when the purge passage is normally connected to the intake pipe.

  Even when the pump is driven in the forward rotation when the pressure P1 is positive, the value of the pressure P2 is lower than the pressure before driving the pump. However, in this case, if the purge passage is separated from the intake pipe, the end of the purge passage is opened to the atmosphere at a pressure lower than the pressure P1, so that the purge passage is normally connected to the intake pipe. The amount of change in pressure P2 increases. When the pump is driven in the forward rotation when the pressure P1 is positive, if the purge passage is disconnected from the intake pipe (abnormality), the differential pressure when the purge passage is normally connected to the intake pipe The differential pressure ΔP becomes larger than ΔP. Therefore, the differential pressure ΔP (P1−P2) created from the detected pressures P1 and P2 is compared with the determination value α2, and when (ΔP ≧ α2), it is determined that the purge passage is disconnected from the intake pipe. Can do. The determination value α2 may be larger than the differential pressure when the purge passage is normally connected to the intake pipe. For example, the determination value α2 may be 2 to 4 kPa greater than the differential pressure when the purge passage is normally connected to the intake pipe.

  Also, when the pump is driven in reverse rotation when the pressure P1 is negative, the value of the pressure P2 increases compared to the pressure before the pump is driven (atmospheric pressure P0). In this case, when the purge passage is separated from the intake pipe, the end of the purge passage is opened to the atmosphere having a pressure higher than the pressure P1, so that the pressure is lower than when the purge passage is normally connected to the intake pipe. The amount of change in P2 increases. When the pump is driven in reverse rotation when the pressure P1 is negative, if the purge passage is disengaged from the intake pipe (an abnormality has occurred), the differential pressure when the purge passage is normally connected to the intake pipe The differential pressure ΔP becomes larger than ΔP. Therefore, the differential pressure ΔP (P2−P1) created from the detected pressures P1 and P2 is compared with the determination value α3, and in the case of (ΔP ≧ α3), it is determined that the purge passage is disconnected from the intake pipe. Can do. The determination value α3 may be larger than the differential pressure when the purge passage is normally connected to the intake pipe. For example, the determination value α3 may be 2 to 4 kPa greater than the differential pressure when the purge passage is normally connected to the intake pipe.

  Even when the pump is driven in reverse rotation when the pressure P1 is positive, the value of the pressure P2 increases compared to the pressure before driving the pump. In this case, when the purge passage is out of the intake pipe, the end of the purge passage is opened to the atmosphere having a pressure lower than the pressure P1, so that the pressure is lower than when the purge passage is normally connected to the intake pipe. The amount of change in P2 becomes small. When the pump is driven in reverse rotation when the pressure P1 is positive, if the purge passage is disconnected from the intake pipe (an abnormality has occurred), the differential pressure when the purge passage is normally connected to the intake pipe The differential pressure ΔP is smaller than ΔP. Therefore, the differential pressure ΔP (P2−P1) created from the detected pressures P1 and P2 is compared with the determination value α4, and in the case of (ΔP ≦ α4), it is determined that the purge passage is disconnected from the intake pipe. Can do. The determination value α4 may be smaller than the differential pressure when the purge passage is normally connected to the intake pipe. For example, the determination value α4 may be 2 to 4 kPa smaller than the differential pressure when the purge passage is normally connected to the intake pipe.

  In the determination method disclosed in the present specification, it may be determined whether the position where the pressure P1 is disposed is a negative pressure, a positive pressure, or an atmospheric pressure. Specifically, a negative pressure (P0−P1 ≧ β1) is set when the value of the pressure P1 is equal to or less than the predetermined value β1 from the atmospheric pressure, and a positive pressure is set when the value of the pressure P1 is equal to or higher than the predetermined value β2 than the atmospheric pressure. (P1−P0 ≧ β2) may be set, and the others may be determined as atmospheric pressure. The predetermined value β1 may be between 2 and 4 kPa. The predetermined value β2 may be between 2 and 4 kPa. The determination method disclosed in the present specification is based on the phenomenon that the differential pressure ΔP is different between the state in which the end of the purge passage is open to the atmosphere and the state in which the purge passage is connected to the intake pipe having the pressure P1. It is determined whether the purge passage is connected to the intake pipe. Therefore, when the pressure P1 is atmospheric pressure (or the difference from the atmospheric pressure is small), it cannot be determined whether or not the purge passage is connected to the intake pipe. By providing the predetermined values β1 and β2, it can be suppressed that the purge passage is disconnected from the intake pipe (erroneous determination) even though the purge passage is connected to the intake pipe.

  In the determination method disclosed in this specification, when it is determined that the pressure P1 is not a negative pressure (when determined to be a positive pressure or an atmospheric pressure), the pressure P1 is adjusted to be a negative pressure. The connection state between the purge passage and the intake pipe may be determined.

(First embodiment)
The evaporative fuel processing apparatus 10 will be described with reference to FIG. The evaporated fuel processing apparatus 10 includes a fuel supply system 2 and a purge gas supply system 8. The evaporated fuel processing apparatus 10 is mounted on a vehicle such as an automobile. The purge gas supply system 8 is connected to the fuel supply system 2 that supplies the fuel stored in the fuel tank FT to the engine EN.

  The fuel supply system 2 supplies fuel injected from a fuel pump (not shown) accommodated in the fuel tank FT to the injector IJ. The injector IJ has an electromagnetic valve whose opening degree is adjusted by an ECU (abbreviation of engine control unit) 100 described later. The injector IJ injects fuel into the engine EN.

  An intake pipe IP and an exhaust pipe EP are connected to the engine EN. The intake pipe IP is an example of an intake path. The intake pipe IP is a pipe for supplying air to the engine EN by the negative pressure of the engine EN or the operation of the supercharger CH. A throttle valve TV is disposed in the intake pipe IP. The throttle valve TV is an example of a second valve. The throttle valve TV is disposed downstream of the supercharger CH and upstream of the intake manifold IM. The amount of air flowing into the engine EN is controlled by adjusting the opening of the throttle valve TV. That is, the throttle valve TV controls the intake amount of the engine EN. The throttle valve TV is controlled by the ECU 100.

  A supercharger CH is arranged upstream of the throttle valve TV of the intake pipe IP. The supercharger CH is a so-called turbocharger, and rotates the turbine by the gas exhausted from the engine EN to the exhaust pipe EP, whereby the air in the intake pipe IP is pressurized and supplied to the engine EN. The supercharger CH is controlled by the ECU 100 to operate when the rotational speed N of the engine EN exceeds a predetermined rotational speed (for example, 2000 rotations).

  An upstream throttle valve 54 is disposed upstream of the supercharger CH of the intake pipe IP. The upstream throttle valve 54 controls the amount of intake air supplied to the supercharger CH. By adjusting the opening degree of the upstream throttle valve 54, the pressure in the intake pipe IP between the upstream throttle valve 54 and the supercharger CH can be controlled. That is, by adjusting the opening degree of the upstream throttle valve 54, the inside of the intake pipe IP between the upstream throttle valve 54 and the supercharger CH can be adjusted to atmospheric pressure or negative pressure. Hereinafter, the inside of the intake pipe IP between the upstream throttle valve 54 and the supercharger CH is referred to as a pressure control unit 56. The pressure control unit 56 is controlled to atmospheric pressure or negative pressure. The pressure controller 56 is provided with a pressure gauge 58. The detection value of the pressure gauge 58 is transmitted to the ECU 100. The pressure of the pressure control unit 56 is controlled by the ECU 100. The pressure gauge 58 is a type that detects absolute pressure, and is an example of a first pressure gauge.

  An air cleaner AC is disposed upstream of the upstream throttle valve 54 of the intake pipe IP. The air cleaner AC has a filter that removes foreign substances from the air flowing into the intake pipe IP. In the intake pipe IP, when the throttle valve TV is opened, air passes through the air cleaner AC and is sucked toward the engine EN. The engine EN burns fuel and air inside, and exhausts the exhaust pipe EP after combustion.

  The ECU 100 is connected to an air-fuel ratio sensor 50 disposed in the exhaust pipe EP. The ECU 100 detects the air-fuel ratio in the exhaust pipe EP from the detection result of the air-fuel ratio sensor 50, and controls the fuel injection amount from the injector IJ.

  The ECU 100 is connected to an air flow meter 52 disposed near the air cleaner AC. The air flow meter 52 is a so-called hot wire type aero flow meter, but may have other configurations. The ECU 100 receives a signal indicating the detection result from the air flow meter 52, and detects the amount of air supplied to the intake pipe IP (the amount of air passing through the upstream throttle valve 54).

  When the supercharger CH is stopped, negative pressure is generated in the intake manifold IM by driving the engine EN. In addition, when stopping the engine EN when the vehicle is stopped, or when the engine EN is stopped and the vehicle is driven by a motor like a hybrid vehicle, in other words, when the drive of the engine EN is controlled for environmental measures, the engine There is no or little negative pressure in the intake manifold IM due to the EN drive. On the other hand, in the situation where the supercharger CH is operating, the downstream side of the supercharger CH is positive pressure, and the upstream side of the supercharger CH is atmospheric pressure or negative pressure.

  In addition, the upstream side (pressure control part 56) may become a positive pressure from the supercharger CH. When exhaust gas of the engine EN, blow-by gas of the engine EN, or the like is supplied to the pressure control unit 56, the pressure control unit 56 may become positive pressure.

  The purge gas supply system 8 supplies the evaporated fuel (purge gas) in the fuel tank FT to the engine EN via the intake pipe IP. The purge gas supply system 8 includes a canister 14, a pump 12, a gas pipe 32, and a purge control valve 34. The gas pipe 32 is an example of a purge passage. The canister 14 adsorbs the evaporated fuel generated in the fuel tank FT. The canister 14 includes an activated carbon 14d and a case 14e that accommodates the activated carbon 14d. The case 14e has a tank port 14a, a purge port 14b, and an atmospheric port 14c. The tank port 14a is connected to the upper end of the fuel tank FT. As a result, the evaporated fuel in the fuel tank FT flows into the canister 14. The activated carbon 14d adsorbs evaporated fuel from the gas flowing from the fuel tank FT into the case 14e. Thereby, it is possible to prevent the evaporated fuel from being released into the atmosphere.

  The atmospheric port 14 c communicates with the gas pipe 20. The gas pipe 20 is an example of an atmospheric passage. An air cutoff valve 28 and an air filter AF are disposed on the gas pipe 20. The air shut-off valve 28 is disposed downstream of the air filter AF (at the air port 14c side). The atmosphere port 14c communicates with the atmosphere via the air filter AF. The air filter AF removes foreign matter from the air flowing into the canister 14 through the atmospheric port 14c. A pressure gauge 36 is provided downstream (at the atmospheric port 14c side) from the atmospheric cutoff valve 28. The pressure gauge 36 is a type that detects absolute pressure, and is an example of a second pressure gauge. Note that the pressure gauge 36 only needs to be provided between the pump 12 and the atmospheric cutoff valve 28, and may be provided between the pump 12 and the purge port 14b, for example. The gas pipe 20 is made of a flexible material such as rubber or resin.

  The purge port 14 b communicates with the gas pipe 32. The gas pipe 32 includes a first hose 22 and a second hose 26. The first hose 22 connects the canister 14 and the pump 12, and the second hose 26 connects the pump 12 and the intake pipe IP. The second hose 26 (gas pipe 32) is connected to the intake pipe IP between the upstream throttle valve 54 and the supercharger CH. That is, the second hose 26 is connected to the pressure control unit 56. The first and second hoses 22 and 26 are made of a flexible material such as rubber or resin.

  The purge gas in the canister 14 flows from the canister 14 into the first hose 22 through the purge port 14b. The purge gas in the first hose 22 is supplied into the intake pipe IP (pressure control unit 56) on the upstream side of the supercharger CH via the pump 12, the purge control valve 34, and the second hose 26.

  The pump 12 is disposed between the canister 14 and the intake pipe IP. The pump 12 is a so-called vortex pump (also called a cascade pump or a Wesco pump) or a centrifugal pump. The pump 12 is controlled by the ECU 100. The suction port of the pump 12 communicates with the canister 14 via the first hose 22.

  The discharge port of the pump 12 is connected to the second hose 26. A purge control valve 34 is provided on the second hose 26. The second hose 26 is connected to the intake pipe IP. The pump 12 can be switched between forward and reverse rotation. That is, when the pump 12 is driven in the forward rotation, the gas moves from the suction port of the pump 12 toward the discharge port, and when the pump 12 is driven in the reverse rotation, the gas moves from the discharge port of the pump 12 toward the suction port. To do.

  After removing the second hose 26 from the intake pipe IP for maintenance or the like, there is a case where the user forgets to attach it again or the second hose 26 falls off the intake pipe IP during traveling. The evaporative fuel processing apparatus 10 can determine whether or not the second hose 26 is connected to the intake pipe IP, as will be described later.

  A purge control valve 34 is arranged on the second hose 26. When the purge control valve 34 is closed, the purge gas is stopped by the purge control valve 34 and does not flow to the second hose 26. On the other hand, when the purge control valve 34 is opened, the purge gas passes through the second hose 26 and flows into the intake pipe IP. Note that when the pump 12 is driven in reverse rotation when the purge control valve 34 is open, the gas in the intake pipe IP flows into the second hose 26 (gas pipe 32). The purge control valve 34 is an electronic control valve and is controlled by the ECU 100.

  A pressure gauge 30 is arranged on the second hose 26. The pressure gauge 30 is also a type that detects absolute pressure. The pressure gauge 30 is disposed between the pump 12 and the purge control valve 34. The pressure loss of the purge control valve 34 can be measured by the pressure gauge 30 and the pressure gauge 58. The pressure loss of the purge control valve 34 changes as the flow rate of the purge gas passing through the purge control valve 34 changes. Specifically, the pressure loss of the purge control valve 34 increases as the flow rate of the purge gas passing through the purge control valve 34 increases.

  The ECU 100 includes a control unit 102 that controls the evaporated fuel processing apparatus 10. The control unit 102 is disposed integrally with another part of the ECU 100 (for example, a part that controls the engine EN). Control unit 102 may be arranged separately from other parts of ECU 100. The control unit 102 includes a CPU and a memory such as a ROM and a RAM. The control unit 102 controls the fuel vapor processing apparatus 10 according to a program stored in advance in the memory. Specifically, the control unit 102 outputs a signal to the pump 12 to control the pump 12. Further, the control unit 102 operates the throttle valve TV and the upstream throttle valve 54, outputs a signal to the purge control valve 34, and executes duty control. The control unit 102 adjusts the valve opening time of the purge control valve 34 by adjusting the duty ratio of the signal output to the purge control valve 34.

(Second embodiment)
With reference to FIG. 2, the evaporative fuel processing apparatus 10a will be described. The evaporated fuel processing apparatus 10a is a modification of the evaporated fuel processing apparatus 10. About the fuel vapor processing apparatus 10a, about the structure same as the fuel vapor processing apparatus 10, description may be abbreviate | omitted by attaching | subjecting the same reference number. In the evaporative fuel processing apparatus 10a, the gas pipe 32 branches into the second hose 26 and the third hose 24 at a branch point 32a at an intermediate position. The second hose 26 is connected to the pressure control unit 56 via a check valve 80. The check valve 80 allows gas supply from the second hose 26 to the intake pipe IP, but prohibits gas supply from the intake pipe IP to the second hose 26. The third hose 24 is connected to the intake pipe IP between the throttle valve TV and the engine EN. The third hose 24 is detachably connected to the intake manifold IM. A check valve 83 is disposed at an intermediate position of the third hose 24. The check valve 83 allows gas to flow in the third hose 24 toward the intake manifold IM, and prohibits the gas from flowing toward the canister 14.

  In the evaporated fuel processing apparatus 10 a, when the control unit 102 opens the purge control valve 34 in a state where the supercharger CH is not operating, the purge gas passes through the first hose 22 and the third hose 24 from the canister 14. Thus, the intake manifold IM is supplied downstream of the supercharger CH. At this time, the control unit 102 controls to drive or stop the pump 12 according to the state of the negative pressure of the intake manifold IM (for example, the rotational speed of the engine EN).

  When a transition is made from a situation where the supercharger CH is not operating to a situation where the supercharger CH is operating, the purge gas passes from the canister 14 through the first hose 22 and the second hose 26, and the supercharger Supplied to the intake pipe IP upstream of CH. At this time, when the inside of the intake pipe IP (pressure control unit 56) is controlled to atmospheric pressure, the control unit 102 may drive the pump 12 to send out purge gas. Thereby, in a situation where the supercharger CH is operating, it is not necessary to supply purge gas to the intake manifold IM on the downstream side of the supercharger CH that is positive pressure.

  On the other hand, when a transition is made from a situation where the supercharger CH is operating to a situation where the supercharger CH is not operating, the purge gas passes through the first hose 22 and the third hose 24 from the canister 14 and takes in the intake gas. Supplied to manifold IM.

  As will be described below, the evaporated fuel processing devices 10 and 10a detect the pressure difference between the pressure gauges 36 and 58 and determine the connection state between the gas pipe 32 and the intake pipe IP. Therefore, in the fuel vapor processing apparatuses 10 and 10a, the pressure gauges 30, 36, and 58 may be a type that detects an absolute pressure or a type that detects a gauge pressure.

  Hereinafter, a method of determining whether or not the gas pipe 32 (second hose 26) is connected to the intake pipe IP (pressure control unit 56) (method of determining the connection state between the intake pipe IP and the second hose 26). explain. The determination method described below can be applied to both the evaporated fuel processing apparatuses 10 and 10a. 3 and 4 relate to a method of controlling the pump 12 by forward rotation when the pressure P1 of the pressure gauge 58 is negative and determining the connection state between the intake pipe IP and the second hose 26 (first determination). Method). 5 and 6 relate to a method of determining the connection state between the intake pipe IP and the second hose 26 by controlling the pump 12 in a normal rotation when the pressure P1 of the pressure gauge 58 is positive (second determination method). . 7 and 8 relate to a method of determining the connection state between the intake pipe IP and the second hose 26 by controlling the pump 12 by reverse rotation when the pressure P1 of the pressure gauge 58 is negative (third determination method). . 9 and 10 relate to a method of determining the connection state between the intake pipe IP and the second hose 26 by controlling the pump 12 in reverse rotation when the pressure P1 of the pressure gauge 58 is positive (fourth determination method). .

  In each determination method, the graphs (FIGS. 3, 5, 7, and 9) show the pumps at timing t <b> 1 with the purge control valve 34 in the open state (fully open) and the atmospheric shut-off valve 28 in the closed state (fully closed). 12 shows a change in the pressure P2 of the pressure gauge 36 when 12 is driven. The horizontal axis indicates time, and the vertical axis indicates pressure. A curve 26a shows a pressure change when the second hose 26 is connected to the intake pipe IP (normal state), and a curve 26b shows a pressure change when the second hose 26 is disconnected from the intake pipe IP (abnormal state). Is shown. In each determination method, the control of the purge control valve 34, the atmospheric cutoff valve 28 and the pump 12, the detection of the pressure gauge 36 and the pressure gauge 58, and the determination of the connection state of the intake pipe IP and the second hose 26 are controlled. It is executed by the determination unit in the unit 102 and the control unit 102.

(First determination method)
As shown in FIG. 3, when the pump 12 is driven in a positive rotation, the pressure P2 is reduced from the atmospheric pressure P0 to a negative pressure. When the pressure P1 is negative, the abnormal pressure P2 (curve 26b) is larger than the normal pressure P2 (curve 26a) (the pressure change is small). Therefore, it is possible to determine whether the pressure is normal or abnormal by calculating the differential pressure ΔP between the pressures P1 and P2 and comparing it with the determination value α1. The determination value α1 is set to a value that is smaller by the difference Pα than the differential pressure between the pressures P1 and P2 in the normal state. The difference Pα is set to 2 kPa, for example.

  The first determination method will be specifically described with reference to FIG. First, it is determined whether or not the pressure P1 is negative (step S2). Specifically, it is determined whether or not the differential pressure between the atmospheric pressure P0 and the pressure P1 is equal to or greater than a predetermined value β1 (P0−P1 ≧ β1). The predetermined value β1 is set to 3 kPa, for example. When the differential pressure between the atmospheric pressure P0 and the pressure P1 is less than β1, even if the pressure P1 indicates a negative pressure, it is determined that the pressure P1 is a negative pressure and the determination of the connection state is not advanced. When the differential pressure between the atmospheric pressure P0 and the pressure P1 is less than the predetermined value β1 (step S2: NO), the process proceeds to the flow 1 in FIG. The flow 1 will be described later.

  When the differential pressure (P0−P1) is equal to or greater than the predetermined value β1 (step S2: YES), the atmospheric shutoff valve 28 (fourth valve) is fully closed (step S4), and the purge control valve 34 (third valve) is fully opened. Then (step S6), the pump 12 is driven in the forward rotation (step S8). Note that the order of steps S4 to S6 is arbitrary. Further, the process may proceed from step 3 through the flow of FIG. 11 to step S4. FIG. 11 will be described later.

  After the value of the pressure P2 is stabilized, the differential pressure ΔP is compared with the determination value α1 (step S10). Specifically, when the differential pressure ΔP (P1−P2) is equal to or less than the determination value α1 (step S10: YES), it is determined that the second hose 26 is disconnected from the intake pipe IP (abnormal) (step S14). When the differential pressure ΔP is less than the determination value α1 (step S10: NO), it is determined that the second hose 26 is connected to the intake pipe IP (normal) (step S12).

(Second determination method)
As shown in FIG. 5, even when the pressure P1 is a positive pressure, when the pump 12 is driven in a positive rotation, the pressure P2 decreases from the atmospheric pressure P0 to a negative pressure. When the pressure P1 is positive, the abnormal pressure P2 (curve 26b) is smaller than the normal pressure P2 (curve 26a). Therefore, it is possible to determine whether the pressure is normal or abnormal by calculating the differential pressure ΔP between the pressures P1 and P2 and comparing it with the determination value α2. Note that the determination value α2 is set to have a difference Pα (Pα = 2 kPa) larger than the differential pressure between the pressures P1 and P2 in the normal state.

  The second determination method will be specifically described with reference to FIG. The second determination method is executed when it is determined by the first determination method that P0−P1 <β1 (FIG. 3, step S2: NO). That is, the second determination method is executed when it is determined that the pressure P1 is not negative. In the second determination method, first, it is determined whether or not a gas (exhaust gas, blow-by gas, etc.) other than the purge gas is introduced into the pressure control unit 56 (see FIGS. 1 and 2) (step S20). When other gas is introduced into the pressure control unit 56, the pressure of the pressure control unit 56 may become a positive pressure (greater than atmospheric pressure). If no other gas is introduced into the pressure control unit 56 (step S20: NO), the determination ends. When “P0−P1 <β1” despite the fact that no other gas is introduced into the pressure control unit 56, the difference between the atmospheric pressure P0 and the pressure P1 of the pressure control unit 56 is small, and the second hose 26 is inhaled. This is because it is not possible to determine whether the second hose 26 is disconnected from the intake pipe IP and opened to the atmosphere.

  When a gas other than the purge gas is introduced into the pressure control unit 56 (step S20: YES), it is determined whether or not the pressure P1 is a positive pressure (step S22). Specifically, it is determined whether or not the differential pressure between the atmospheric pressure P0 and the pressure P1 is equal to or greater than a predetermined value β2 (P1−P0 ≧ β2). The predetermined value β2 is set to 3 kPa, for example. When the differential pressure between the atmospheric pressure P0 and the pressure P1 is less than β2, even if the pressure P1 indicates a positive pressure, the determination of the connection state cannot proceed because the pressure P1 is a positive pressure. If the differential pressure between the atmospheric pressure P0 and the pressure P1 is less than the predetermined value β2 (step S22: NO), the determination ends.

  When the differential pressure (P1−P0) is equal to or greater than the predetermined value β2 (step S22: YES), the air shutoff valve 28 (fourth valve) is fully closed (step S24), similarly to steps S4 to S8 in FIG. The purge control valve 34 (third valve) is fully opened (step S26), and the pump 12 is driven in the normal rotation (step S28).

  After the pump 12 is driven and the value of the pressure P2 is stabilized, the differential pressure ΔP is compared with the determination value α2 (step S30). Specifically, when the differential pressure ΔP (P1−P2) is equal to or greater than the determination value α2 (step S30: YES), it is determined that the second hose 26 is disconnected from the intake pipe IP (abnormal) (step S34). When the differential pressure ΔP is less than the determination value α2 (step S30: NO), it is determined that the second hose 26 is connected to the intake pipe IP (normal) (step S32).

(Third determination method)
As shown in FIG. 7, when the pump 12 is driven in reverse rotation, the pressure P2 rises from the atmospheric pressure P0 and becomes a positive pressure. When the pressure P1 is negative, the abnormal pressure P2 (curve 26b) is larger than the normal pressure P2 (curve 26a). Even if the pump 12 is driven in reverse rotation, it is possible to determine whether the pressure is normal or abnormal by calculating the differential pressure ΔP between the pressures P1 and P2 and comparing it with the determination value α3. The determination value α3 is set to a value that is larger by the difference Pα (Pα = 2 kPa) than the differential pressure between the pressures P1 and P2 in the normal state.

  The third determination method will be specifically described with reference to FIG. First, similarly to steps S2 to S6 of the first determination method (FIG. 4), it is determined whether or not the pressure P1 (gauge pressure) is a negative pressure (step S42). If the pressure P1 is a negative pressure (step S42: If YES, the atmospheric shutoff valve 28 (fourth valve) is fully closed (step S44), the purge control valve 34 (third valve) is fully opened (step S46), and the pump 12 is driven (step S48). In this determination method, the pump 12 is driven in reverse rotation (step S48). When the pressure P1 is not negative (step S42: NO), the process proceeds to the flow 2 in FIG.

  After the pump 12 is driven and the value of the pressure P2 is stabilized, the differential pressure ΔP is compared with the determination value α3 (step S50). Specifically, when the differential pressure ΔP (P2-P1) is equal to or greater than the determination value α3 (step S50: YES), it is determined that the second hose 26 is disconnected from the intake pipe IP (abnormal) (step S54). . When the differential pressure ΔP is less than the determination value α3 (step S50: NO), it is determined that the second hose 26 is connected to the intake pipe IP (normal) (step S52).

(Fourth determination method)
As shown in FIG. 9, even when the pressure P1 is positive, when the pump 12 is driven in reverse rotation, the pressure P2 rises from the atmospheric pressure P0 and becomes positive. When the pressure P1 is positive, the abnormal pressure P2 (curve 26b) is smaller than the normal pressure P2 (curve 26a). Therefore, by calculating the differential pressure ΔP between the pressures P1 and P2 and comparing it with the determination value α4, it is possible to determine whether the pressure is normal or abnormal. The determination value α4 is set to a value that is a difference Pα (Pα = 2 kPa) smaller than the differential pressure between the pressures P1 and P2 in the normal state.

  The fourth determination method will be specifically described with reference to FIG. The fourth determination method is executed when it is determined by the third determination method that P0−P1 <β1 (FIG. 8, step S42: NO), that is, when it is determined that the pressure P1 is not a negative pressure. First, similarly to steps S20 to S28 of the second determination method (FIG. 6), it is determined whether or not a gas other than the purge gas is introduced into the pressure control unit 56 (step S60), and the pressure control unit 56 is not purged gas. Is introduced (step S60: YES), it is determined whether or not the pressure P1 is positive (step S62). If the pressure P1 is positive (step S62: YES), the air cutoff valve 28 ( The fourth valve) is fully closed (step S64), the purge control valve 34 (third valve) is fully opened (step S66), and the pump 12 is driven (step S68). In this determination method, the pump 12 is driven in reverse rotation.

  After the pump 12 is driven and the value of the pressure P2 is stabilized, the differential pressure ΔP is compared with the determination value α4 (step S70). When the differential pressure ΔP (P2-P1) is equal to or less than the determination value α4 (step S70: YES), it is determined that the second hose 26 is disconnected (abnormal) from the intake pipe IP (step S74). When the differential pressure ΔP is less than the determination value α4 (step S70: NO), it is determined that the second hose 26 is connected to the intake pipe IP (normal) (step 72).

(Fifth determination method)
The fifth determination method will be described with reference to FIG. The fifth determination method is a modification of the second and fourth determination methods. That is, the fifth determination method is a modification of the flow 1 or 2, and is executed when it is determined that P1 is not a negative pressure (step S2 in FIG. 4: NO, step S42 in FIG. 6: NO). .

  First, it is determined whether or not a gas other than the purge gas (other gas) is introduced into the pressure control unit 56 (step S80), and when it is introduced (step S80: YES), the introduction of the other gas is stopped (step S80). Step S82). After stopping the introduction of the other gas and when no other gas is introduced (step S80: NO), the upstream throttle valve (first valve) 54 is fully closed (step S84). When the upstream throttle valve 54 is fully closed while the engine EN is driven, the pressure P1 of the pressure control unit 56 decreases. Thereafter, it is determined whether or not the pressure P1 is a negative pressure (step S86). When the pressure P1 is not negative (step S86: NO), the pressure of the pressure controller 56 is decreased until the pressure P1 becomes negative. When the pressure P1 becomes negative (step S86: YES), the upstream throttle valve 54 is closed to stop the control of the pressure control unit 56, and the process proceeds to step S4 in FIG. 4 or step S44 in FIG. Determination of the connection state between the hose 26 and the intake pipe IP is advanced. The description after step S4 and after step S44 is omitted.

  As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: Evaporative fuel processing device 12: Pump 14: Canister 20: Atmospheric passage 28: Second valve 32: Purge passage 34: Third valve 54: First valve CH: Supercharger EN: Internal combustion engine FT: Fuel tank IP: Intake pipe TV: Second valve

Claims (6)

An intake pipe through which air supplied to the internal combustion engine passes;
A turbocharger provided in the intake pipe;
A first valve that is provided in the intake pipe upstream of the supercharger and controls the amount of air supplied to the supercharger;
A second valve that is provided in the intake pipe downstream of the supercharger and controls the intake air amount of the internal combustion engine;
A canister that adsorbs the evaporated fuel evaporated in the fuel tank;
A purge passage connected to the intake pipe between the first valve and the supercharger, through which purge gas sent from the canister to the internal combustion engine passes;
A third valve that is provided in the purge passage and controls the amount of purge gas supplied to the intake pipe;
A pump provided in the purge passage between the canister and the third valve, for sending purge gas into the intake pipe;
An atmospheric passage connected to the canister and having one end open to the atmosphere;
A fourth valve that is provided in the air passage and controls the opening of the air passage;
An evaporative fuel processing apparatus. A first pressure gauge for detecting a pressure in the intake pipe between the first valve and the supercharger;
A second pressure gauge for detecting the pressure in the passage between the pump and the fourth valve;
A determination unit that controls states of the third valve, the fourth valve, and the pump, and that determines a connection state between the intake pipe and the purge passage based on detection values of the first pressure gauge and the second pressure gauge;
The evaporative fuel processing apparatus of Claim 1 provided with.   The evaporative fuel processing apparatus according to claim 1, wherein the pump is of a type that can be switched between forward and reverse rotations. A method for determining a connection state between an intake pipe and a purge passage in the fuel vapor processing apparatus according to any one of claims 1 to 3,
Open the third valve (purge valve), close the fourth valve (leak check valve), and drive the pump;
Detecting the pressure P1 in the intake pipe between the first valve and the supercharger and the pressure P2 in the passage between the pump and the fourth valve;
By comparing the detected differential pressure between the pressure P1 and the pressure P2 with a determination value based on the differential pressure between the pressure P1 and the pressure P2 when the intake pipe and the purge passage are connected, the intake pipe and the purge passage A determination method for determining a connection state.   The determination method according to claim 4, wherein the determination value is created based on a detection value of the pressure P1.   The determination method according to claim 4 or 5, wherein when determining a connection state between the intake pipe and the purge passage, the pump sends out gas toward the fourth valve.

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