JP2011226349A - Internal combustion engine - Google Patents

Abstract

An object of the present invention is to simplify the configuration and control of a system by combining a PCV mechanism and an alcohol adsorbent.
An engine using alcohol fuel includes a PCV passage for recirculating gas in a crankcase to an intake passage, a PCV valve provided in the PCV passage, and an alcohol incorporated in the PCV valve. And an adsorbent 44. The alcohol adsorbent 44 has a function of adsorbing and desorbing alcohol according to the surrounding pressure atmosphere. Thus, the negative pressure acting on the alcohol adsorbent 44 is controlled using the PCV valve 42, and the alcohol in the gas is adsorbed on the adsorbent 44, or the adsorbed alcohol is desorbed and supplied into the cylinder. it can. Accordingly, it is not necessary to separately prepare gasoline and alcohol injection systems, so that the system configuration and control can be simplified.
[Selection] Figure 1

Description

  The present invention relates to an internal combustion engine using alcohol fuel, and more particularly to an internal combustion engine equipped with a PCV mechanism.

  As a prior art, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2009-138569), an internal combustion engine that uses two types of fuel composed of alcohol fuel and gasoline is known. The internal combustion engine of the prior art includes two fuel tanks that respectively store these two types of fuel, and two fuel injection valves that inject each fuel into the intake passage. During the operation of the internal combustion engine, the injection ratio of the two fuels is variably set according to the operation state so as to ensure startability and the like.

  On the other hand, as other conventional technologies, Patent Document 2 (Japanese Patent Laid-Open No. 2008-215214), Patent Document 3 (Japanese Patent Laid-Open No. 2009-257222), and the like disclose PCV that recirculates blowby gas in a crankcase to an intake passage. An internal combustion engine having a (Positive Crankcase Ventiration) mechanism is disclosed.

JP 2009-138569 A JP 2008-215214 A JP 2009-257222 A

  By the way, in the prior art of Patent Document 1, two fuel tanks and two fuel injection valves are prepared for each of gasoline and alcohol, and an air-fuel mixture is formed by mixing these two types of fuels at a desired ratio. I am doing so. However, with this configuration, the system for forming the air-fuel mixture becomes large and complicated. In addition, it is necessary to perform fuel injection while considering the remaining amount of fuel stored in each fuel tank. For this reason, in the prior art, there is a problem that the configuration and control of the fuel injection system are complicated and the reliability of the system is lowered.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to simplify the configuration and control of the system by supplying alcohol to the intake system using the PCV mechanism, An object of the present invention is to provide an internal combustion engine capable of improving reliability.

A first invention includes an in-cylinder injection valve that injects alcohol fuel into a cylinder;
A PCV passage for recirculating gas in the crankcase to the intake passage;
A flow control valve provided in the PCV passage, wherein the PCV valve adjusts the amount of gas flowing through the PCV passage;
An adsorbent having a function of adsorbing alcohol in a gas flowing through the PCV passage and a function of desorbing the adsorbed alcohol, wherein the function is switched according to an ambient pressure atmosphere;
It is characterized by providing.

  According to a second aspect of the invention, the PCV valve is constituted by an adsorbent-integrated valve in which the alcohol adsorbent is built.

  According to a third aspect of the invention, the alcohol adsorbent has a function of adsorbing alcohol in the gas in a pressurized state and desorbing the adsorbed alcohol in a reduced pressure state. Even when the valve is closed, it is provided at a position in contact with the gas in the crankcase.

According to a fourth aspect of the present invention, there is provided a pre-warm-up PCV suppressing means that limits the opening of the PCV valve between the start and the warm-up, and suppresses the recirculation amount of the gas to a minimum.
An alcohol request determination means for determining whether or not the alcohol adsorbed by the alcohol adsorbent needs to be supplied into the cylinder in a state where the warm-up is completed;
Alcohol supply control for closing the PCV valve when the alcohol request determining means determines that the supply of alcohol is unnecessary, and opening the PCV valve when it is determined that the alcohol supply is required Means,
Is provided.

  According to a fifth aspect of the invention, the alcohol demand determination means determines that it is necessary to supply alcohol in an operation region where knocking is likely to occur.

  According to a sixth aspect of the invention, the alcohol supply control means controls the opening of the PCV valve based on knocking strength when the alcohol demand determination means determines that the supply of alcohol is necessary. It is said.

  According to a seventh aspect of the invention, the alcohol demand determination means determines that it is necessary to supply alcohol during idle operation at a high load.

  According to the first invention, by combining the PCV passage, the PCV valve, and the alcohol adsorbing material, the negative pressure acting on the alcohol adsorbing material can be controlled using the PCV valve. Thereby, the alcohol contained in the gas can be adsorbed to the alcohol adsorbent at a desired timing. Then, the adsorbed alcohol can be desorbed from the adsorbent as needed and supplied into the cylinder. As a result, the alcohol concentration of the air-fuel mixture can be appropriately controlled according to the operating state. Therefore, unlike the prior art, it is not necessary to prepare the gasoline and alcohol injection systems individually, so that the configuration and control of the system can be simplified and the reliability can be improved.

  According to the second invention, an adsorbent-integrated PCV valve incorporating an alcohol adsorbent can be used. Thereby, the number of parts of a system can be reduced and a system can be constituted compactly.

  According to the third invention, when the PCV valve is fully closed, a high pressure on the crankcase side can be applied to the alcohol adsorbent. In this state, the alcohol in the gas can be adsorbed and stored on the adsorbent. Further, when the PCV valve is opened, it is possible to generate a gas flow while applying an intake negative pressure to the alcohol adsorbent. Thereby, alcohol can be desorbed from the adsorbent and this alcohol can be supplied into the cylinder.

  According to the fourth aspect of the invention, the pre-warm-up PCV suppressing means allows the air-fuel ratio immediately after start-up while appropriately recirculating the gas in the crankcase to the intake system in the semi-warm-up state from start to warm-up completion. Can be stabilized. The alcohol supply control means can close the PCV valve when the supply of alcohol into the cylinder is unnecessary. When alcohol supply is required, the PCV valve can be opened. Thereby, the alcohol concentration of the air-fuel mixture can be appropriately controlled.

  According to the fifth aspect, in the operation region where knocking is likely to occur, the alcohol concentration of the air-fuel mixture can be increased and the occurrence of knocking can be effectively suppressed. Further, even when knocking occurs, the strength can be reduced.

  According to the sixth aspect of the invention, the amount of alcohol supplied into the cylinder (alcohol concentration of the mixture) is appropriately controlled according to the knock strength, and knocking can be accurately suppressed with the minimum amount of alcohol supplied. it can.

  According to the seventh aspect of the present invention, the alcohol concentration of the air-fuel mixture can be increased during idling at a high load where fuel consumption tends to deteriorate. Thereby, deterioration of a fuel consumption can be suppressed and the fuel consumption performance of a vehicle can be improved.

It is a whole block diagram for demonstrating the system configuration | structure of Embodiment 1 of this invention. In Embodiment 1 of this invention, it is a flowchart of the control performed by ECU.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an overall configuration diagram for explaining a system configuration according to the first embodiment of the present invention. The system of the present embodiment includes an engine 10 as an internal combustion engine mounted on, for example, an FFV (Flexible Fuel Vehicle), and the engine 10 operates using alcohol fuel in which alcohol and gasoline are mixed. Each cylinder of the engine 10 is provided with a piston 12, and a combustion chamber 14 is defined by the piston 12. The piston 12 is connected to a crankshaft 16 that is an output shaft of the engine. The engine 10 also includes an intake passage 18 that sucks intake air into each cylinder, and an exhaust passage 20 through which exhaust gas is discharged from each cylinder. The intake passage 18 is connected to the intake port of each cylinder, and the exhaust passage 20 is connected to the exhaust port of each cylinder.

  The intake passage 18 is provided with an air flow sensor 22 for detecting the intake air amount and an electronically controlled throttle valve 24. The throttle valve 24 is driven by a throttle motor 26 based on the accelerator opening and the like to increase or decrease the intake air amount. On the other hand, the exhaust passage 20 is provided with a catalyst 28 for purifying exhaust gas. Each cylinder has a fuel injection valve 30 for injecting alcohol fuel into the combustion chamber 14 (in the cylinder), an ignition plug 32 for igniting the air-fuel mixture in the cylinder, and an intake port opened to the cylinder. An intake valve 34 that closes and an exhaust valve 36 that opens and closes the exhaust port with respect to the inside of the cylinder are provided.

  Further, the engine 10 includes a PCV mechanism provided between the intake passage 18 and the crankcase 38. This PCV mechanism includes a PCV passage 40 that recirculates blow-by gas in the crankcase 38 to the intake passage 18, a PCV valve 42 provided in the PCV passage 40, and an alcohol adsorbent 44 built in the PCV valve 42. ing. Here, the upstream portion 40 </ b> A of the PCV passage 40 is connected to the crankcase 38, and the downstream portion 40 </ b> B is connected to the intake passage 18.

  The PCV valve 42 is constituted by, for example, a generally known electric flow control valve. Specifically, the PCV valve 42 includes a housing in which a gas flow path is provided, a valve body that is displaceably disposed in the housing, and opens and closes the gas flow path. A return spring that is always urged in the valve closing direction and an actuator that electromagnetically attracts and opens the valve body are provided. Further, the gas flow path in the housing is connected between the upstream portion 40 </ b> A and the downstream portion 40 </ b> B of the PCV passage 40 and constitutes a part of the PCV passage 40.

  The valve body of the PCV valve 42 is driven to an arbitrary opening degree between the fully closed position and the fully opened position in accordance with a control signal input to the actuator, and the flow path of the gas passage according to the opening degree. The area changes. Thereby, the PCV valve 42 is configured to adjust the amount of gas flowing through the PCV passage 40 in accordance with a control signal input from the ECU 60 described later. Further, the PCV valve 42 adjusts the intake negative pressure acting on the upstream portion 40 </ b> A of the PCV passage 40 and the alcohol adsorbent 44. In FIG. 1, in order to make the PCV valve 42 and the alcohol adsorbent 44 easy to understand, these are illustrated in an enlarged manner than other structures.

  The PCV valve 42 is configured as an adsorbent-integrated valve in which an alcohol adsorbent 44 is incorporated. The alcohol adsorbent 44 adsorbs alcohol vapor in the blow-by gas flowing through the PCV passage 40, and is made of a generally known adsorbent material having high adsorption performance for alcohol. The alcohol adsorbent 44 has a function of adsorbing and desorbing alcohol according to the surrounding pressure atmosphere. Specifically, the alcohol adsorbent 44 adsorbs alcohol in the gas in a pressurized state where the ambient pressure is higher than a reference pressure (for example, atmospheric pressure). Further, in a reduced pressure state where the ambient pressure is lower than the reference pressure, the alcohol adsorbed on the alcohol adsorbent 44 is desorbed.

  Further, the alcohol adsorbent 44 is disposed in the housing of the PCV valve 42 at a position closer to the crankcase 38 than the valve body. This position is a position that communicates with the space in the crankcase 38 via the upstream portion 40A of the PCV passage 40 even when the PCV valve 42 is fully closed. Therefore, the alcohol adsorbent 44 comes into contact with the blow-by gas in the crankcase 38 even when the PCV valve 42 is fully closed. In the present embodiment, the alcohol adsorbing material 44 is arranged inside the PCV valve 42. However, the present invention is not limited to this, and the alcohol adsorbing material is formed as a separate component from the PCV valve 42. The alcohol adsorbent may be provided in the upstream portion 40A of the PCV passage 40.

  Further, as shown in FIG. 1, the system according to the present embodiment includes a sensor system including a crank angle sensor 46, a water temperature sensor 48, a knock sensor 50, and the like, and an ECU (Electronic Control Unit) that controls the operating state of the engine 10. 60. First, the sensor system will be described. The crank angle sensor 46 outputs a signal synchronized with the rotation of the crankshaft 16, and the ECU 60 can detect the engine speed and the crank angle based on this output. The water temperature sensor 48 detects the temperature of the engine cooling water (engine water temperature) as the engine temperature of the engine, and the knock sensor 50 detects the occurrence of knocking due to vibration of the engine body or the like.

  In addition to the sensors 22, 46 to 50, the sensor system includes various sensors necessary for controlling the engine 10 and a vehicle on which the engine 10 is mounted (for example, an accelerator opening sensor that detects an accelerator opening, an exhaust air-fuel ratio is detected). An air-fuel ratio sensor, a fuel property sensor for detecting the alcohol concentration in the fuel, and the like. These sensors are connected to the input side of the ECU 60. Further, the ECU 60 is configured to receive, for example, an operating state of a headlight or an air conditioner, a shift range of an automatic transmission, and the like, and detect the operating state of these in-vehicle devices as a load. On the other hand, various actuators including a throttle motor 26, a fuel injection valve 30, a spark plug 32, a PCV valve 42, and the like are connected to the output side of the ECU 60.

  Then, the ECU 60 drives each actuator while detecting operation information of the engine with a sensor system, and executes operation control. More specifically, the engine speed and the crank angle are detected based on the output of the crank angle sensor 46, and the intake air amount is calculated based on the output of the air flow sensor 22. Also, the engine load (load factor) is calculated based on the intake air amount, engine speed, etc., the fuel injection timing is determined based on the crank angle, and the fuel injection amount is determined based on the intake air amount, load, etc. calculate. When the fuel injection timing comes, the fuel injection valve 30 is driven, and then the spark plug 32 is driven. Thereby, the air-fuel mixture is combusted in the cylinder, and the engine can be operated. Further, the ECU 60 drives the PCV valve 42 according to the operating state and controls the negative pressure acting on the upstream portion 40A of the PCV passage 40 and the alcohol adsorbent 44 based on the opening degree. Thereby, ECU60 performs control described below.

[Operation of Embodiment 1]
In the present embodiment, alcohol vapor in blow-by gas is adsorbed to the alcohol adsorbent 44 while performing normal PCV control with the adsorbent-integrated PCV valve 42. When the engine is warmed up and alcohol supply to the cylinder is required, the flow of blow-by gas is used to supply alcohol adsorbed by the adsorbent 44 into the cylinder. Yes.

(PCV control)
During the operation of the engine, a part of the fuel injected into the cylinder enters the crankcase 38 via the sliding portion between the cylinder inner wall surface and the piston 12, and this fuel is mixed into the lubricating oil. (Oil dilution) is likely to occur. In particular, in the in-cylinder injection type engine 10, since the injected fuel tends to adhere to the in-cylinder inner wall surface, oil dilution occurs remarkably. When oil dilution occurs, the deterioration of the lubricating oil easily proceeds. For this reason, in PCV control, blow-by gas containing fuel that has entered the crankcase 38 is recirculated to the intake system to suppress oil dilution. Specifically, for example, when it is estimated that the degree of oil dilution is large based on the operating state of the engine, by opening the PCV valve 42 and controlling the intake negative pressure acting on the crankcase 38 side, Blow-by gas is sucked from the PCV passage 40 into the intake passage 18. At this time, the recirculation amount of the gas is appropriately controlled based on the opening degree of the PCV valve 42 so as not to greatly affect the combustion control.

  As a specific example of the PCV control, in the present embodiment, for example, the opening of the PCV valve 42 is limited to a predetermined small opening after the engine is cold-started until the warm-up is completed. Minimize the flow rate of blow-by gas. Between the cold start and the warm-up completion, the engine is in a semi-warm-up state, and blow-by gas is rapidly generated as the temperature in the crankcase 38 rises. Therefore, this gas is returned to the intake system. It is preferable to do so. On the other hand, in the semi-warm-up state, combustion is not yet completely stabilized, so it is desired to avoid deterioration of the exhaust emission due to the air-fuel ratio being disturbed by blow-by gas. For this reason, the prescribed small opening described above is set so as to ensure the minimum amount of recirculation required during half warm-up within a range that does not disturb the air-fuel ratio. Therefore, according to the above control, the air-fuel ratio control at the start can be stably performed while the blowby gas is appropriately recirculated in the half warm-up state from the start to the completion of the warm-up.

(Alcohol supply control)
This control is performed in parallel with the PCV control after completion of warm-up, and supplies alcohol adsorbed by the alcohol adsorbent 44 into the cylinder when alcohol is required during combustion in the cylinder. It is. As described above, the alcohol adsorbent 44 has a function of adsorbing alcohol vapor in the blow-by gas in a pressurized state and desorbing the adsorbed alcohol in a reduced pressure state. For this reason, in the alcohol supply control, for example, the PCV valve 42 is fully closed in an operation state in which the supply of alcohol into the cylinder is unnecessary, and there is no problem even if the PCV control is interrupted. In the state where the PCV valve 42 is fully closed, the high pressure in the crankcase 38 that has risen due to the completion of warm-up acts on the alcohol adsorbent 44 via the PCV passage 40. As a result, the alcohol adsorbent 44 comes into contact with the blow-by gas in the PCV passage 40 under a pressurized atmosphere, so that the alcohol vapor in the gas is adsorbed. Therefore, when it is not necessary to supply alcohol into the cylinder, the PCV valve 42 can be fully closed and the alcohol in the blow-by gas can be stored in the adsorbent 44.

  Further, in the alcohol supply control, for example, the PCV valve 42 is opened in an operation state in which alcohol supply into the cylinder is required and there is no problem even if the PCV control is executed. In a state where the PCV valve 42 is opened, intake negative pressure acts in the PCV passage 40, and a flow of blow-by gas occurs. As a result, the alcohol stored in the alcohol adsorbent 44 is desorbed from the adsorbent 44 in a reduced pressure atmosphere and released into the blow-by gas. The released alcohol flows into the intake passage 18 together with the blow-by gas and is supplied into the cylinder to contribute to combustion. Therefore, when it is necessary to supply alcohol into the cylinder, the PCV valve 42 can be opened to supply alcohol from the adsorbent 44 into the cylinder. And at the time of supply of alcohol, the supply amount (flow rate) of alcohol can be adjusted based on the opening degree of the PCV valve 42, and the alcohol concentration of the air-fuel mixture can be controlled appropriately.

  Next, a specific example in the case where alcohol supply into the cylinder is necessary will be described. In the present embodiment, for example, when an operation in an operation region (knock region) where knocking is likely to occur or when an idle operation with a high load is performed, alcohol supply to the cylinder is necessary. Judge that there is. First, the operation in the knock region will be described. In the ECU 60, map data for determining the knock region based on, for example, the engine speed and the load is stored in advance. An example of the knock region is an operation region with a high load or high output. When the ECU 60 detects operation in the knock region based on the map data, the ECU 60 determines that alcohol supply to the cylinder is necessary, and opens the PCV valve 42.

  Here, the combustion temperature and combustion speed when the air-fuel mixture burns in the cylinder decrease as the alcohol concentration of the air-fuel mixture increases. Therefore, if alcohol is supplied into the cylinder from the alcohol adsorbent 44 in the knock region, the alcohol concentration of the air-fuel mixture can be increased, and the occurrence of knocking can be effectively suppressed. Further, even when knocking occurs, the strength can be reduced. Further, the ECU 60 detects the knocking strength (knock strength) based on the output of the knock sensor 50 in the knocking region. And the opening degree of the PCV valve | bulb 42 is enlarged, so that knock intensity | strength is large. According to this control, the supply amount of alcohol (alcohol concentration of the air-fuel mixture) can be appropriately controlled according to the knock strength, and knocking can be accurately suppressed with the minimum required alcohol supply amount.

  In the present embodiment, the case where the opening degree of the PCV valve 42 is controlled based on the knock intensity detected by the knock sensor 50 is exemplified. However, the present invention is not limited to this. For example, the opening degree of the PCV valve 42 may be controlled based on the operation region without using the knock sensor 50. In this case, map data for determining the opening degree of the PCV valve 42 based on the operation region may be used by utilizing the fact that there is a correlation between the operation region and the knock magnitude.

  On the other hand, in the alcohol supply control, when an idle operation with a high load is performed, it is determined that alcohol supply into the cylinder is necessary, and the PCV valve 42 is opened (fully opened). The idle operation at a high load is, for example, an idle operation in a state where a head ride or an air conditioner is operated or the shift range of the automatic transmission is switched to the D range. In such an operating state, the fuel consumption of the engine is likely to deteriorate, so the alcohol concentration of the air-fuel mixture is increased to suppress the deterioration of the fuel consumption. Thereby, the fuel consumption performance of the vehicle can be improved.

[Specific Processing for Realizing Embodiment 1]
FIG. 2 is a flowchart of control executed by the ECU in the first embodiment of the present invention. The routine shown in this figure is repeatedly executed while the engine is operating. In the routine shown in FIG. 2, first, reading and calculation of engine operation information is executed based on the output of the sensor system (step 100). This operation information includes at least the engine speed, the crank angle, the intake air amount, the engine water temperature, the load, the presence or absence of knocking, the strength, and the like.

  In the next process, it is determined whether or not the engine has been warmed up (step 102). Specifically, for example, it is determined whether or not the engine water temperature is higher than a determination temperature of about 50 ° C. If this determination is not established, the state is a semi-warm-up state, so the opening degree of the PCV valve 42 is controlled to a prescribed small opening degree, and the process is ended as it is (step 104). On the other hand, if the determination in step 102 is established, warm-up has been completed, and as described above, the map data is referred to based on the engine speed and the load, and the current operation region is the knock region. Whether or not (step 106).

  If the current operation region is the knock region, the PCV valve 42 is opened and the opening degree is controlled based on the knock intensity (step 108). As a result, an amount of alcohol corresponding to the opening of the PCV valve 42 is supplied from the alcohol adsorbent 44 to the intake passage 18. When the current operation region is a non-knock region, the PCV valve 42 is fully closed (step 110). Thereby, the alcohol in the blowby gas is adsorbed on the alcohol adsorbent 44. In step 110, when a request for opening the PCV valve 42 is generated by the PCV control, the PCV valve 42 may be opened as necessary.

  In the next process, it is determined whether or not an idle operation with a high load is being performed (step 112). If this determination is established, the PCV valve 42 is fully opened and alcohol is supplied into the cylinder (step 114). If the determination in step 114 is not satisfied, the PCV valve 42 is fully closed, and the alcohol adsorbent 44 is made to adsorb alcohol (step 116). Also in this case, the PCV valve 42 may be opened as necessary.

  As described above in detail, according to the present embodiment, the negative pressure acting on the alcohol adsorbent 44 can be controlled using the PCV valve 42 by combining the PCV mechanism and the alcohol adsorbent 44. Thereby, the alcohol contained in the blow-by gas can be adsorbed to the alcohol adsorbent 44 at a desired timing. Then, the adsorbed alcohol can be desorbed from the adsorbent 44 as necessary and supplied into the cylinder. As a result, it is possible to appropriately control the alcohol concentration of the air-fuel mixture according to the driving state, to suppress the occurrence of knocking due to high output driving or deterioration with time, and to improve the fuel efficiency of the vehicle.

  Therefore, the alcohol concentration of the air-fuel mixture can be controlled without preparing separate gasoline and alcohol injection systems as in the prior art, thus simplifying the system configuration and control and improving reliability. Can be made. In particular, by incorporating the alcohol adsorbent 44 in the PCV valve 42, the number of parts of the system can be reduced and the system can be made compact.

  In the above embodiment, step 104 in FIG. 2 shows a specific example of the pre-warm-up PCV suppressing means in claim 4, steps 106 and 112 show a specific example of the alcohol demand determination means, and steps 108 and 110. , 114 and 116 show specific examples of the alcohol supply control means.

10 Engine 12 Piston 14 Combustion chamber 16 Crankshaft 18 Intake passage 20 Exhaust passage 22 Air flow sensor 24 Throttle valve 26 Throttle motor 28 Catalyst 30 Fuel injection valve 32 Spark plug 34 Intake valve 36 Exhaust valve 38 Crankcase 40 PCV passage 40A Upstream portion 40B Downstream part 42 PCV valve 44 Alcohol adsorbent 46 Crank angle sensor 48 Water temperature sensor 50 Knock sensor 60 ECU

Claims (7)

An in-cylinder injection valve that injects alcohol fuel into the cylinder;
A PCV passage for recirculating gas in the crankcase to the intake passage;
A flow control valve provided in the PCV passage, wherein the PCV valve adjusts the amount of gas flowing through the PCV passage;
An adsorbent having a function of adsorbing alcohol in a gas flowing through the PCV passage and a function of desorbing the adsorbed alcohol, wherein the function is switched according to an ambient pressure atmosphere;
An internal combustion engine comprising:   2. The internal combustion engine according to claim 1, wherein the PCV valve is configured by an adsorbent-integrated valve in which the alcohol adsorbent is incorporated.   The alcohol adsorbent has a function of adsorbing alcohol in the gas in a pressurized state and desorbing the adsorbed alcohol in a depressurized state, and the alcohol adsorbent also when the PCV valve is closed The internal combustion engine according to claim 1 or 2, wherein the internal combustion engine is provided at a position in contact with gas in the crankcase. Pre-warm-up PCV suppression means that limits the opening of the PCV valve from the start to the completion of warm-up and suppresses the recirculation amount of the gas to a minimum;
An alcohol request determination means for determining whether or not the alcohol adsorbed by the alcohol adsorbent needs to be supplied into the cylinder in a state where the warm-up is completed;
Alcohol supply control for closing the PCV valve when the alcohol request determining means determines that the supply of alcohol is unnecessary, and opening the PCV valve when it is determined that the alcohol supply is required Means,
An internal combustion engine according to claim 3, comprising:   5. The internal combustion engine according to claim 4, wherein the alcohol demand determination unit determines that the supply of alcohol is necessary in an operation region where knocking is likely to occur.   The said alcohol supply control means becomes a structure which controls the opening degree of the said PCV valve based on the intensity | strength of knocking, when it determines with the alcohol request | requirement determination means determining that the supply of alcohol is required. Internal combustion engine.   The internal combustion engine according to any one of claims 4 to 6, wherein the alcohol demand determination means determines that it is necessary to supply alcohol during idle operation at a high load.

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