JP2009150291A - Blow-by gas recirculation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blow-by gas recirculation device capable of preventing abnormal increase in engine rotation speed and preventing ignition of combustible oil mist discharged into the atmosphere when the pressure in a crankcase rises excessively. <P>SOLUTION: An intake passage 4 and an exhaust passage 6 are respectively connected to a first side portion and a second side portion of an engine body 2 with respect to the direction of arrangement of cylinders. The blow-by gas recirculation device includes a blow-by gas recirculation passage 26 for introducing blow-by gas in the crankcase to the intake passage 4, a cutoff valve 30 arranged in the blow-by gas recirculation passage 26, and an escape valve 32 arranged on the first side portion separately from the blow-by gas recirculation passage 26 so as to discharge the blow-by gas in the crankcase to the outside thereof when the escape valve is opened. When the pressure Pc in the crankcase becomes equal to or higher than an upper limit pressure Po, the cutoff valve 30 is closed and the escape valve 32 is opened. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a blow-by gas recirculation device that recirculates blow-by gas in a crankcase of an engine to an intake system.

  Since the air-fuel mixture and combustion gas leaked from the piston ring provided on the piston of the engine flow into the crankcase of the engine, the pressure rises. In order to suppress such an increase in pressure in the crankcase, it has been conventionally performed to discharge blow-by gas in the crankcase to the outside of the crankcase. Particularly in recent years, a blow-by gas recirculation device that recirculates the blow-by gas in the crankcase to the intake system of the engine in consideration of the influence of the blow-by gas release on the atmosphere is proposed by, for example, Patent Document 1 Has been.

The blow-by gas recirculation device of Patent Document 1 is provided with a blow-by gas recirculation path that communicates between the crankcase of the engine and the intake port of the turbocharger, and the escape that is interposed in the blow-by gas recirculation path. A valve, a coalescer / filter for oil separation, and the like are integrally combined. Of these, the relief valve mechanically responds to the pressure in the crankcase when the pressure in the crankcase rises excessively, and releases part of the blow-by gas into the atmosphere. By providing the relief valve, the pressure in the crankcase and the pressure of the blow-by gas supplied to the intake port of the turbocharger are prevented from rising excessively.
JP-A-10-115212

  However, in the blow-by gas recirculation device of Patent Document 1, even if the pressure in the crankcase rises excessively, only a part of the blow-by gas is released into the atmosphere by the relief valve, and the remaining blow-by gas is discharged. Is still returned to the intake system of the engine. The excessive increase in the crankcase pressure is caused by the high pressure gas in the combustion chamber leaking into the crank chamber due to damage to the piston ring or cylinder or piston loss. Contains a large amount of flammable oil mist. A part of this combustible oil mist is separated by a breather inserted in the blow-by gas recirculation path, but if the blow-by gas is continuously recirculated to the engine intake system when the pressure in the crankcase rises excessively, A large amount of combustible oil mist in the blow-by gas thus supplied is supplied to the combustion chamber of the engine, which may cause a problem that the rotation of the engine abnormally increases.

  Further, when the blowby gas is supplied to the intake port of the turbocharger as in the blowby gas recirculation device of Patent Document 1, the turbocharger is generally provided on the exhaust system side of the engine. If the blow-by gas recirculation device is configured integrally like the blow-by gas recirculation device of Document 1, the blow-by gas recirculation device is disposed on the exhaust system side of the engine. Therefore, in such a blow-by gas recirculation device, when the pressure in the crankcase increases excessively, the blow-by gas is discharged from the relief valve to the exhaust system side. At this time, as described above, since the blow-by gas contains a large amount of combustible oil mist, the combustible oil mist contained in the blow-by gas discharged from the relief valve becomes a high-temperature exhaust system component such as an exhaust pipe. If attached, this combustible oil mist may ignite.

  The present invention has been made in view of such a problem, and an object of the present invention is to prevent an abnormal increase in engine rotation when the pressure in the crankcase increases excessively, and in the atmosphere. An object of the present invention is to provide a blow-by gas recirculation device capable of preventing ignition of discharged combustible oil mist.

  In order to achieve the above object, a blow-by gas recirculation device according to the present invention is an engine blow-by gas recirculation device that performs intake from a first side and exhaust to a second side with respect to the cylinder arrangement direction of the engine. A blow-by gas recirculation path for guiding blow-by gas in the engine crankcase to the intake system of the engine, a shut-off valve interposed in the blow-by gas recirculation path, and the blow-by gas on the first lateral side. A relief valve provided separately from the gas recirculation path, capable of discharging blow-by gas in the crankcase to the outside of the crankcase when the valve is opened, pressure detecting means for detecting the pressure in the crankcase, and When the pressure in the crankcase detected by the pressure detection means does not reach a predetermined upper limit pressure, the shutoff valve is opened and the relief is released. And a control means for closing the shut-off valve and opening the relief valve when the pressure in the crankcase becomes equal to or higher than the upper limit pressure while closing the valve. 1).

  According to the blow-by gas recirculation device configured as described above, when the pressure in the crankcase detected by the pressure detection means does not reach the predetermined upper limit pressure, the control means opens the shut-off valve and releases the relief valve. By closing the valve, the blow-by gas in the crankcase is recirculated to the engine intake system via the blow-by gas recirculation path, and the blow-by gas is not released out of the crankcase via the relief valve.

On the other hand, when the pressure in the crankcase detected by the pressure detection means exceeds the upper limit pressure, the control means closes the shut-off valve and opens the relief valve, so that the intake air of the engine via the blow-by gas recirculation path is opened. The recirculation of the blow-by gas to the system is stopped, and the blow-by gas in the crankcase is discharged out of the crankcase via the relief valve.
Further, in the blow-by gas recirculation device, the control means is configured such that when the pressure in the crankcase becomes equal to or higher than the upper limit pressure, the fuel to the engine is greater than when the pressure in the crankcase does not reach the upper limit pressure. The supply amount is limited (claim 2).

According to the blow-by gas recirculation device configured in this way, when the pressure in the crankcase detected by the pressure detection means exceeds the upper limit pressure, in addition to stopping the blow-by gas recirculation to the intake system, the fuel supply to the engine The amount is limited.
In the blow-by gas recirculation device, the control means issues a warning when the pressure in the crankcase becomes equal to or higher than the upper limit pressure.

According to the blowby gas recirculation device configured as described above, when the pressure in the crankcase detected by the pressure detection means becomes equal to or higher than the upper limit pressure, an alarm is issued by the control means.
Further, in the blow-by gas recirculation device, the control means may provide data for failure diagnosis regarding that the pressure in the crankcase becomes equal to or higher than the upper limit pressure when the pressure in the crankcase becomes equal to or higher than the upper limit pressure. It is memorized (claim 4).

  According to the blow-by gas recirculation device configured as described above, when the pressure in the crankcase detected by the pressure detection means is equal to or higher than the upper limit pressure, the control means indicates that the pressure in the crankcase is equal to or higher than the upper limit pressure. The data for failure diagnosis is stored.

  According to the blow-by gas recirculation device of the present invention, when the pressure in the crankcase becomes equal to or higher than the upper limit pressure, the control means closes the shut-off valve and opens the relief valve, whereby the engine via the blow-by gas recirculation path is opened. Since the return of the blow-by gas to the intake system is stopped, an abnormal increase in engine rotation due to a large amount of oil mist contained in the blow-by gas being supplied to the intake system of the engine can be reliably prevented.

  At this time, the blow-by gas in the crankcase is released to the outside of the crankcase via the relief valve, but the relief valve is located on the first side where intake is performed, on both sides of the cylinder arrangement direction of the engine. Since it is provided, it is possible to reliably prevent ignition of the oil mist generated when the oil mist contained in the blow-by gas adheres to the high-temperature exhaust system components.

  Further, when the pressure in the crankcase exceeds the upper limit pressure, the piston ring may be damaged or the cylinder or the piston may be lost. If the engine is continuously operated normally, the engine may be further damaged. Therefore, according to the blow-by gas recirculation device of claim 2, when the pressure in the crankcase becomes equal to or higher than the upper limit pressure, in addition to stopping the blow-by gas recirculation to the intake system, the fuel supply amount to the engine is limited. It is possible to keep the engine speed low and prevent further engine damage.

Further, according to the blowby gas recirculation device of the third aspect, when the pressure in the crankcase becomes equal to or higher than the upper limit pressure, an alarm is issued by the control means, so that an abnormality has occurred in the engine reliably and promptly. Can do.
According to the blowby gas recirculation device of the fourth aspect, when the pressure in the crankcase becomes equal to or higher than the upper limit pressure, data for failure diagnosis is stored in the control means that the pressure in the crankcase is equal to or higher than the upper limit pressure. Therefore, the cause of the failure can be easily investigated by using this data when performing a failure diagnosis later at a maintenance shop or the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of a four-cylinder in-vehicle diesel engine (hereinafter referred to as an engine) to which a blow-by gas recirculation device according to an embodiment of the present invention is applied. The configuration of the blow-by gas recirculation device based on FIG. explain.
The engine 1 has an engine body 2 including a crankcase (none of which is shown) that houses a crankshaft. The engine body 2 shown in FIG. 1 is in a state viewed from a cylinder arrangement direction (not shown). Show. The engine body 2 is connected to an intake passage 4 for supplying intake air to each cylinder of the engine body 2 from the left side of FIG. An exhaust passage 6 for exhausting exhaust gas from each of the two cylinders is connected from the right side of FIG. 1, that is, from the second side with respect to the cylinder arrangement direction.

  The intake passage 4 is provided with a compressor 8a of a turbocharger 8. The intake air sucked from the atmosphere through the air cleaner 10 flows into the compressor 8a, and the intake air supercharged by the compressor 8a is intercooled. It is introduced into each cylinder of the engine body 2 via the cooler 12 and the intake control valve 14. An intake air amount sensor 16 for detecting the intake air flow rate to the engine body 2 is provided between the air cleaner 10 and the compressor 8a.

  On the other hand, a turbine 8b of a turbocharger 8 is interposed in the exhaust passage 6. The exhaust discharged from the engine body 2 flows into the turbine 8b and drives the turbine 8b, and then the exhaust throttle valve 18 is opened. Through the exhaust aftertreatment device 20. Note that the rotating shaft of the turbine 8b is connected to the rotating shaft of the compressor 8a, and the turbine 8b is driven by the exhaust to rotate the compressor 8a, thereby supercharging the intake air. The exhaust gas flowing into the exhaust aftertreatment device 20 is purified by the exhaust aftertreatment device and released into the atmosphere.

Each cylinder of the engine main body 2 is provided with a fuel injector 22 for injecting fuel supplied from a fuel injection pump (not shown) into the cylinder.
In the crankcase of the engine body 2, blow-by gas composed of air-fuel mixture, combustion gas, etc. leaks from a gap between piston rings provided in the pistons of the cylinders. Therefore, in order to take out this blow-by gas from the crankcase, a breather 24 is attached to the engine body 2 for communicating with the crankcase and separating flammable oil mist in the blow-by gas.

  The breather 24 communicates with the intake passage 4 at a position immediately upstream of the compressor 8a of the turbocharger 8 by the blow-by gas communication passage 26. The blow-by gas from which part of the oil mist is separated by the breather 24 is supplied to the compressor 8a. It can be recirculated during the inflowing intake air. A PCV valve 28 for adjusting the pressure of the blowby gas recirculated during intake is interposed in the blowby gas recirculation path 26, and a shutoff valve 30 is interposed between the PCV valve 28 and the breather 24. It is intervened. The shut-off valve 30 is an electromagnetic valve that can be switched between an open state and a closed state. In the open state, the shut-off valve 30 allows the return of the blow-by gas to the intake passage 4 via the blow-by gas return path 26, but is closed. In the valve state, the recirculation of blow-by gas to the intake passage 4 via the blow-by gas recirculation path 26 is blocked.

  Further, on the first side of the engine body 2, that is, the side where the intake passage 4 is connected, the air inside the crankcase and outside the crankcase is separated from the blowby gas communication passage 26. A communicating relief valve 32 is mounted. The relief valve 32 is an electromagnetic valve that can be switched between an open state and a closed state. In the open state, the release valve 32 allows the release of blow-by gas from the crankcase into the atmosphere. Block the release of blow-by gas.

Further, the engine body 2 is provided with a pressure sensor (pressure detection means) 34 for detecting the pressure in the crankcase and outputting the detection result.
In order to control each device of the engine 1 configured as described above and to operate the engine 1 properly, the engine 1 is provided with an ECU (control means) 36. The ECU 36 includes a CPU, a memory, a timer counter, and the like. The ECU 36 calculates various control amounts and controls various devices based on the control amounts.

  Further, the ECU 36 stores failure diagnosis data such as the operating state of the engine 1 at the time of occurrence of the failure, the date and time of occurrence of the failure, and the content of the failure in order to efficiently perform repairs when a failure occurs in the engine 1. A failure diagnosis data storage unit 38 is provided. The failure diagnosis data stored in the failure diagnosis data storage unit 38 is read out by a failure diagnosis device connected to the ECU 36 and used for failure diagnosis when repairing the generated failure.

  In addition to the intake air amount sensor 16 and the pressure sensor 34 described above, various sensors are connected to the input side of the ECU 36 in order to collect information necessary for various controls. On the other hand, various devices such as an intake control valve 14, an exhaust throttle valve 18, an injector 22 for each cylinder, a cutoff valve 30, and a relief valve 32 that are controlled based on the calculated control amount are connected to the output side of the ECU 36. Has been.

  Further, the ECU 36 is connected with an alarm unit 40 for giving an alarm when a failure or abnormality occurs in the engine 1. This alarm unit 40 is provided in the passenger compartment, and when any failure or abnormality occurs in the engine 1, it gives an alarm according to the content of the failure or abnormality and informs the driver of the vehicle accordingly. . In addition, about the method of warning, lighting of a warning lamp, alerting | reporting by an audio | voice or a buzzer, etc. are suitably selected according to the content of warning.

  The ECU 36 performs calculation of the fuel supply amount to each cylinder of the engine body 2 and fuel supply control from the injector 22 based on the calculated fuel supply amount as one of various controls for the engine 1. The fuel supply amount (main injection amount) necessary for the operation of the engine body 2 is determined by reading from a map stored in advance based on the detection results of various sensors. The amount of fuel supplied to each cylinder is adjusted by the valve opening time of the injector 22, and each injector 22 is driven to open during a driving time corresponding to the determined fuel amount, and main injection is performed in each cylinder. Thus, the amount of fuel necessary for the operation of the engine body 2 is supplied.

Further, when the pressure in the crankcase of the engine body 2 rises excessively, the ECU 36 monitors the pressure in the crankcase in order to respond appropriately and prevent abnormal operation or damage to the engine body 2. Perform pressure monitoring control. Below, the detail of such pressure monitoring control is demonstrated based on FIG.
FIG. 2 is a flowchart of pressure monitoring control that is executed by the ECU 36 at a predetermined control cycle when the engine body 2 is operated.

  When the operation of the engine body 2 is started, the ECU 36 determines whether or not the value of the flag F1 is 1 in step S1. The flag F1 has a value of 1 to indicate that the pressure in the crankcase has increased excessively. The initial value after starting the engine body 2 is 0. Accordingly, here, assuming that the value of the flag F1 is not 1, the ECU 36 proceeds with the process to step S2.

In step S2, the ECU 36 determines whether or not the pressure Pc in the crank chamber detected by the pressure sensor 34 is equal to or higher than a predetermined upper limit pressure Po. The upper limit pressure Po is set assuming that an abnormality occurs in the engine body 2 and the pressure in the crankcase is excessively increased.
If there is no abnormality in the engine body 2 and the pressure Pc in the crank chamber has not reached the predetermined upper limit pressure Po, the ECU 36 proceeds to step S3 and maintains the value of the flag F1 at 0. Further, in step S4, the ECU 36 selects the normal fuel injection amount required for the normal operation of the engine body 2 obtained according to the operating state of the engine 1 as the fuel injection amount of the main injection in each cylinder of the engine body 2. To do. The fuel injection amount selected here is used in fuel supply control separately performed by the ECU 36 in parallel. Accordingly, here, a normal fuel injection amount of fuel is supplied from the fuel injector 22 to each cylinder.

The ECU 36 closes the relief valve 32 in step S5, opens the shut-off valve 30 in step S6, and further in step S7, notifies the alarm unit 40 to warn of a pressure abnormality in the crankcase. After the provided warning lamp is turned off, the control cycle ends.
In the next control cycle, the ECU 36 starts the process again from step S1, and determines whether or not the value of the flag F1 is 1. Since the value of the flag F1 is still 0, the ECU 36 proceeds to step S2, and determines whether or not the pressure Pc in the crank chamber detected by the pressure sensor 32 is equal to or higher than a predetermined upper limit pressure Po. Therefore, as long as there is no abnormality in the main body of the engine 2 and the pressure Pc in the crank chamber has not reached the predetermined upper limit pressure Po, the processes of steps S1 to S7 are repeated every control cycle.

  At this time, the normal fuel injection amount is supplied to the engine body 2 from the fuel injector 22 to each cylinder, and the engine body 2 is operated in a normal operation state. Then, the blow-by gas taken out from the crankcase through the breather 24 passes through the shut-off valve 30 in the open state, and is returned to the intake passage 4 upstream of the compressor 8a by the blow-by gas return passage 26. Further, by maintaining the relief valve 32 in the closed state, the blow-by gas in the crankcase is not released into the atmosphere, and the warning of the abnormal pressure by the alarm unit 40 is not performed.

On the other hand, when an abnormality occurs in the engine body 2 and the pressure in the crankcase increases, and it is determined in step S2 that the pressure Pc in the crank chamber detected by the pressure sensor 34 is equal to or higher than the predetermined upper limit pressure Po, the ECU 36 Advances the process from step S2 to step S8, and sets the value of the flag F1 to 1.
Further, in step S9, the ECU 36 sets a fuel injection amount that is limited to a smaller amount than the normal fuel injection amount as a fuel injection amount to each cylinder of the engine main body 2 in order to operate the engine main body 2 at a predetermined rotational speed (eg, 1500 rpm) or less. select. Accordingly, fuel is supplied to the cylinders of the engine body 2 in such a limited amount of fuel injection by the fuel supply control performed in parallel, and the engine body 2 is operated at a predetermined speed or less. As a result, it is possible to prevent the damage to the engine body 2 such as damage to the piston ring and cylinder or piston loss, which are thought to be the cause of the pressure increase in the crankcase, and to slowly move the vehicle to the road shoulder or the repair shop. It becomes possible.

  Next, the ECU 36 opens the relief valve 32 in step S10, and closes the shut-off valve 30 in step S11. As a result, the recirculation of blow-by gas to the intake passage 4 via the blow-by gas recirculation path 26 is stopped, and the blow-by gas in the crankcase is released into the atmosphere via the relief valve 32. Accordingly, an abnormal increase in the rotational speed of the engine body 2 due to a large amount of combustible oil mist mixed in the blow-by gas being returned to the intake system is prevented, and an excessive increase in the pressure in the crank chamber is prevented. Is suppressed, and further damage to the engine body 2 is prevented.

  At this time, the relief valve 32 is mounted not on the side of the engine body 2 to which the exhaust passage 6 is connected but on the side to which the intake passage 4 is connected. Therefore, the blow-by gas released from the relief valve 32 The combustible oil mist contained inside is difficult to adhere to high-temperature exhaust system parts. Accordingly, it is possible to reliably prevent the oil mist from being ignited by the heat generated by the exhaust system parts.

  The ECU 36 further proceeds to step S12 to turn on the warning lamp of the alarm unit 40, warn that the pressure in the crankcase has increased excessively, and in step S13, to the failure diagnosis data storage unit 38 in the crankcase. The fault diagnosis data relating to the excessive pressure increase is saved, and the control cycle ends. This failure diagnosis data includes, for example, the date and time when an excessive pressure increase occurred, the operating state of the engine 1 at that time, the pressure in the crankcase, and the like. When the engine body 2 is later repaired at a repair shop or the like. The data is read out by a failure diagnosis device connected to the ECU 36 and used for failure diagnosis.

  In the next control cycle, the ECU 36 starts the process again from step S1, and determines whether or not the value of the flag F1 is 1. Since the value of the flag F1 is set to 1 when the pressure in the crankcase increases excessively, the ECU 36 proceeds directly to step S9, and performs the above-described steps S9 to S13. Therefore, once the pressure PC in the crankcase becomes equal to or higher than the upper limit pressure Po, the processes of steps S1, S2 and S9 to S13 are repeated every control cycle. As a result, the fuel injection amount to each cylinder is limited from the normal fuel injection amount, and the rotational speed of the engine body 2 is suppressed to a predetermined rotational speed or less, and the blow-by gas is supplied to the intake passage 4 by the blow-by gas recirculation path 26. Reflux is stopped, the blow-by gas in the crankcase is released into the atmosphere via the relief valve 32, and the state where an alarm is issued by the alarm unit 40 is maintained. By doing so, even if the pressure Pc in the crankcase temporarily falls below the upper limit pressure Po for some reason, the restriction on the fuel injection amount and the stop of the blow-by gas recirculation to the intake system are released. Thus, further damage to the engine body 2 can be reliably prevented.

  By performing the pressure monitoring control as described above, when the pressure Pc in the crankcase increases excessively and exceeds the upper limit pressure Po, the ECU 36 closes the shutoff valve 30 and opens the relief valve 32. By setting the state, the return of the blow-by gas to the intake system via the blow-by gas return path 26 is stopped, so that a large amount of combustible oil mist contained in the blow-by gas is supplied to each cylinder of the engine body 2. Therefore, it is possible to reliably prevent an abnormal increase in engine rotation.

  At this time, the blow-by gas in the crankcase is released to the outside of the crankcase via the relief valve 32, and the relief passage 32 is connected to the intake passage 4 on both sides of the engine body 2 with respect to the cylinder arrangement direction. Since it is provided on the first lateral side, it is possible to reliably prevent ignition of oil mist caused by the combustible oil mist contained in the blow-by gas adhering to the high-temperature exhaust system components.

Furthermore, when the pressure Pc in the crankcase becomes equal to or higher than the upper limit pressure Po, the fuel injection amount in the engine body 2 is limited, so that the engine speed can be kept low and further damage to the engine body 2 can be prevented. It is possible to move the vehicle slowly to the shoulder or repair shop.
In addition, since the warning light of the alarm unit 40 is turned on when the pressure Pc in the crankcase becomes equal to or higher than the upper limit pressure Po, the vehicle driver can immediately confirm that an abnormality has occurred in the pressure in the crankcase and It becomes possible to recognize with certainty.

Further, when the pressure Pc in the crankcase becomes equal to or higher than the upper limit pressure Po, failure diagnosis data is stored in the failure diagnosis data storage unit 38 for the fact that the pressure Pc in the crankcase exceeds the upper limit pressure Po. By using this failure diagnosis data for failure diagnosis when repairing at a factory or the like, the cause of the failure can be easily investigated.
Although the description of the blow-by gas recirculation apparatus according to one embodiment of the present invention is finished above, the present invention is not limited to the above-described embodiment.

For example, in the above embodiment, when the pressure Pc in the crankcase becomes equal to or higher than the upper limit pressure Po, the fuel injection amount to each cylinder is limited. However, the fuel injection to each cylinder may be stopped. In this case, it is difficult to move the vehicle by itself to a maintenance shop or the like, but further damage to the engine body 2 can be more reliably prevented by stopping fuel injection.
In the above embodiment, once the pressure Pc in the crankcase becomes equal to or higher than the upper limit pressure Po, even if the pressure Pc in the crankcase temporarily falls below the upper limit pressure Po, step S9 in the flowchart of FIG. The process from S13 to S13 is repeatedly executed. However, when the pressure Pc in the crankcase falls below the upper limit pressure Po, the process may be returned to the normal state, that is, the processes from Steps S4 to S7.

Further, in the above embodiment, when the pressure Pc in the crankcase becomes equal to or higher than the upper limit pressure Po, the warning light of the alarm unit 40 is turned on to give an alarm, but the alarm method is not limited to this. The alarm can be changed as appropriate, such as a buzzer or an alarm.
In the above embodiment, the engine main body 2 is a four-cylinder in-vehicle diesel engine. However, the number of cylinders, the type, and the use of the engine 1 are not limited thereto, and the present invention is applied to various engines. It is possible.

1 is an overall configuration diagram of an engine to which a blow-by gas recirculation device according to an embodiment of the present invention is applied. It is a flowchart of the pressure monitoring control performed with the blowby gas recirculation apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Engine main body 4 Intake passage 6 Exhaust passage 26 Blow-by gas recirculation passage 30 Shut-off valve 32 Relief valve 34 Pressure sensor (pressure detection means)
36 ECU (control means)
38 Fault diagnosis data storage unit 40 Alarm unit

Claims (4)

An engine blow-by gas recirculation device that performs intake from a first side and exhaust to a second side with respect to the cylinder arrangement direction of the engine,
A blow-by gas recirculation path that guides the blow-by gas in the crankcase of the engine to the intake system of the engine;
A shut-off valve interposed in the blow-by gas recirculation path;
A relief valve provided separately from the blow-by gas recirculation path on the first lateral side, and capable of discharging blow-by gas in the crank case to the outside of the crank case when the valve is opened;
Pressure detecting means for detecting the pressure in the crankcase;
When the pressure in the crankcase detected by the pressure detection means does not reach a predetermined upper limit pressure, the shut-off valve is opened and the relief valve is closed, while the pressure in the crankcase is A blow-by gas recirculation device comprising: a control means for closing the shut-off valve and opening the relief valve when the pressure exceeds the pressure.   When the pressure in the crankcase becomes equal to or higher than the upper limit pressure, the control means limits the amount of fuel supplied to the engine compared to when the pressure in the crankcase does not reach the upper limit pressure. The blowby gas recirculation apparatus according to claim 1.   The blow-by gas recirculation apparatus according to claim 1, wherein the control means issues a warning when the pressure in the crankcase becomes equal to or higher than the upper limit pressure.   The control means, when the pressure in the crankcase becomes equal to or higher than the upper limit pressure, stores data for failure diagnosis that the pressure in the crankcase is equal to or higher than the upper limit pressure. The blowby gas reflux device according to 1.

Images