JP2007198353A - Evaporative fuel control device of engine provided with supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a malfunction from occurring in a check valve due to negative pressure remaining in the section between a purge valve and the check valve in the purge passage. <P>SOLUTION: As shown in Fig.1, the evaporative fuel control device 50 of an engine provided with a supercharger comprises a canister 51 for storing the evaporative fuel occurring in a fuel tank 23, a purge passage 54 which allows the canister 51 to communicate with an intake passage 30 to supply the evaporative fuel to the intake passage 30, a purge valve 55 which is placed in the purge passage 54 to control the amount of the evaporative-fuel supply from the canister 51 to the intake passage 30, and a check valve 56 which is placed closer to the intake passage than the purge valve 55 in the purge passage 54. The check valve 56 shuts off the air flow from the intake passage 30 to the canister 51 in the case when the pressure on the side of the intake passage in the purge passage 54 is higher than the pressure on the canister side. Further, a purge-valve control part 60c is provided to open the purge valve 55 for a specified time T2 after stop of the engine 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In recent years, technology that contributes to the protection of the natural environment has been regarded as important. For example, for automobiles and the like having an engine, the vaporized fuel generated in a fuel tank or the like is prevented from being released into the atmosphere to prevent air pollution. Technology is essential. As this technique, for example, an evaporative fuel control apparatus as disclosed in Patent Document 1 has been known.

  In the evaporative fuel control apparatus according to Patent Document 1, evaporative fuel generated in a fuel tank or the like is temporarily stored (adsorbed) in a canister, and the accumulated evaporative fuel is detached from the canister in accordance with predetermined operating conditions of the engine. The purged air is mixed with purge air, and the purged mixture is supplied to the intake passage of the engine while controlling the flow rate with a purge valve via the purge passage, thereby preventing evaporation of evaporated fuel to the atmosphere. .

When such an evaporative fuel control device is used in an engine with a supercharger, when the pressure in the intake passage becomes positive by the compressor of the supercharger, the intake air flows backward from the intake passage to the canister side. There is a problem that the fuel in the canister may be diffused into the atmosphere. Therefore, the evaporated fuel control device according to Patent Document 1 provides a check valve in the purge passage to prevent the intake air from flowing backward from the intake passage to the canister even when the pressure in the intake passage becomes positive. I try to prevent it.
Japanese Patent Laid-Open No. 1-170751

  However, in the configuration in which the purge valve and the check valve are provided in the purge passage as in the evaporated fuel control device according to Patent Document 1, the portion between the purge valve and the check valve in the purge passage after the engine is stopped. Negative pressure may remain in In such a case, the valve body of the check valve is pressed more than necessary against the valve seat by the negative pressure. Further, when the engine 1 is operated, the inside of the engine room may become hot and the temperature of the check valve may become high. In this way, when the check valve is at a high temperature and the negative pressure described above remains after the engine stops, at least one of the valve body and the valve seat of the check valve is formed of resin or the like. In such a case, there is a possibility that the valve body and / or the valve seat is melted and both are fixed.

  The present invention has been made in view of such points, and the object of the present invention is to cause a problem in the check valve due to the negative pressure remaining in the portion between the purge valve and the check valve in the purge passage. It is to prevent that.

  In the present invention, the portion of the purge passage between the purge valve and the check valve is opened to the atmosphere after the engine is stopped.

  Specifically, the first invention provides a canister for storing evaporated fuel generated in a fuel tank, and a purge for supplying the evaporated fuel stored in the canister to the intake passage by communicating the canister and the intake passage. A purge valve provided in the purge passage for controlling the amount of fuel vapor supplied from the canister to the intake passage; a valve body; and a valve seat on which the valve body is seated. The valve body is provided on the intake passage side of the purge valve in the passage, and the valve body is seated on the valve seat when the pressure on the intake passage side in the purge passage is higher than the pressure on the canister side. The target is an evaporated fuel control device for a supercharged engine equipped with a check valve for blocking air flow from the intake passage to the canister. The purge valve control means is further provided for opening the purge valve for a predetermined opening time after the engine is stopped.

  In the case of the above-described configuration, if the purge valve is always closed after the engine is stopped, the portion between the purge valve and the check valve in the purge passage is connected by the purge valve from the canister side. Since the inflow of air is blocked by the check valve from the intake passage side, negative pressure may remain. Therefore, the purge valve control means opens the purge valve for a predetermined opening time after the engine stops, thereby opening a portion between the purge valve and the check valve in the purge passage to the atmosphere. The pressure in the part changes from negative pressure to atmospheric pressure.

  As a result, the valve body constituting the check valve is prevented from being pressed more than necessary against the valve seat by the negative pressure remaining in the portion between the purge valve and the check valve. Even if the temperature of the stop valve rises, the valve body and the valve seat can be prevented from sticking to each other.

  According to a second invention, in the first invention, an intake pressure sensor provided in the intake passage for detecting an intake pressure of the intake passage, and the intake pressure sensor when a predetermined waiting time has elapsed after the engine is stopped. An intake pressure sensor failure diagnosing unit that performs the failure diagnosis of the intake pressure sensor, and the purge valve control unit opens the purge valve for the opening time after the failure diagnosis by the intake pressure sensor failure diagnosing unit is executed. Shall.

  In the case of the above configuration, the intake pressure sensor failure diagnosis means performs failure diagnosis of the intake pressure sensor after the engine is stopped. In such a configuration, if the purge valve is opened after the engine is stopped in order to change the pressure in the purge passage between the purge valve and the check valve from negative pressure to atmospheric pressure, the intake pressure sensor may fail. Despite the diagnosis, air may flow from the canister side to the intake passage side, and the pressure in the intake passage may fluctuate. Then, there is a possibility that failure diagnosis of the intake pressure sensor cannot be performed accurately. Therefore, the purge valve control means waits for the failure diagnosis by the intake pressure sensor failure diagnosis means to be performed, and then opens the purge valve for the predetermined opening time, thereby performing the failure diagnosis of the intake pressure sensor. While performing accurately, the part between the purge valve and the check valve in the purge passage can be opened to the atmosphere to prevent the check valve from malfunctioning.

A third invention further comprises an atmospheric pressure sensor for detecting atmospheric pressure in the second invention,
The intake pressure sensor failure diagnosis means performs failure diagnosis of the intake pressure sensor based on a difference between a detection value of the intake pressure sensor and a detection value of the atmospheric pressure sensor.

  In the third aspect of the invention, the failure diagnosis method of the intake pressure sensor failure diagnosis means in the second aspect of the invention is specified. That is, the intake pressure sensor failure diagnosing means performs failure diagnosis based on the difference between the detected value of the intake pressure sensor and the detected value of the atmospheric pressure sensor after the predetermined waiting time has elapsed. Therefore, if the purge valve is opened after the engine is stopped, air may flow from the canister side to the intake passage side, affecting the detection value of the intake pressure sensor, and the failure diagnosis of the intake pressure sensor may not be performed accurately. However, since the purge valve control means opens the purge valve after waiting for the failure diagnosis by the intake pressure sensor failure diagnosis means to be performed, the detection value of the intake pressure sensor is not affected. In addition, failure diagnosis of the intake pressure sensor can be performed accurately.

  According to a fourth aspect, in the first aspect, the apparatus further comprises temperature detecting means for detecting a temperature related to the temperature of the check valve, and the purge valve control means has a predetermined temperature detected by the temperature detecting means. When the temperature is higher than the temperature, the purge valve is opened for the opening time.

  In the case of the above configuration, only when the temperature related to the temperature of the check valve is high, that is, when the check valve is hot, the purge control means opens the purge valve after the engine is stopped and The part between the purge valve and the check valve is opened to the atmosphere. This prevents the purge valve from being unnecessarily opened when the possibility that the valve body and the valve seat of the check valve stick together is low, thereby suppressing the operation frequency of the purge valve. As a result, the durability of the purge valve can be improved.

  According to the present invention, since the purge valve control means opens the purge valve for a predetermined opening time after the engine stops, the portion between the purge valve and the check valve in the purge passage is opened to the atmosphere. The valve body is prevented from being pressed against the valve seat more than necessary due to negative pressure, and as a result, even if the check valve becomes hot, the valve body and the valve seat are prevented from sticking, and the reverse It is possible to prevent the malfunction of the stop valve.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic diagram of an engine 1 that employs an evaporated fuel control device according to the present invention.

  The engine 1 includes a cylinder block 3 in which a plurality of cylinders 2 (only one is shown) are provided in series, and a cylinder head 4 disposed on the cylinder block 3. The piston 5 is inserted so as to be able to reciprocate, and a combustion chamber 6 is defined between the crown surface of the piston 5 and the lower surface of the cylinder head 4.

  The cylinder head 4 is formed with an intake port 12 and an exhaust port 13 for each cylinder 2. The intake port 12 and the exhaust port 13 are provided such that the inner ends open to the ceiling surface of the combustion chamber 6 and the outer ends open to one side and the other side of the cylinder head 4, respectively. . An intake valve 14 and an exhaust valve 15 are arranged at the inner ends of the intake port 12 and the exhaust port 13 so as to open and close the inner ends.

  The cylinder head 4 is provided with a spark plug 16 along the axis of each cylinder 2. The electrode at the tip of the spark plug 16 is disposed so as to face the combustion chamber 6 from the ceiling surface of the combustion chamber 6.

  Further, the cylinder head 4 is provided with an injector 20 with the injection port facing the intake side peripheral portion of the combustion chamber 6 for each cylinder 2. The injectors 20 of these cylinders 2 are connected to a fuel supply pipe 22 via fuel distribution pipes (not shown) extending in the cylinder row direction, whereby high-pressure fuel discharged from the high-pressure fuel pump 21 is supplied to each cylinder 2. It is distributed and supplied to the injector 20.

  In the illustrated example, the high-pressure fuel pump 21 is connected to the fuel tank 23 by a fuel passage 24, and the low-pressure fuel pump 25, the low-pressure regulator 26, and the filter 27 are sequentially arranged from the upstream side to the downstream side of the fuel passage 24. Etc. are arranged. The low-pressure fuel pump 25 is arranged so as to be immersed in the fuel in the fuel tank 23, sucks up the fuel and sends it out to the fuel passage 24. The fuel is regulated by a low pressure regulator 26, filtered by a filter 27, supplied to a high pressure fuel pump 21, boosted by the high pressure fuel pump 21, and discharged to a fuel supply pipe 22. On the other hand, surplus fuel is returned to the low pressure side and is returned to the fuel tank 23 through the return passage 28.

  As shown in FIG. 1, an intake passage 30 is connected to one side of the engine 1 so as to communicate with the intake port 12 of each cylinder 2. The intake passage 30 supplies air filtered by the air cleaner 31 to the combustion chamber 6 of the engine 1, and the flow rate of air (intake air) sucked into the engine 1 in order from the upstream side to the downstream side. An air flow sensor 32 that detects the intake air temperature, an intake air temperature sensor 33 that detects the intake air temperature, a compressor 34 that is driven by a turbine 41 described later to compress the intake air, and an intercooler 35 that cools the intake air compressed by the compressor 34. An electric throttle valve 36 for adjusting the cross-sectional area of the intake passage 30 and a surge tank 37 are provided. The intake passage 30 on the downstream side of the surge tank 37 is an independent passage branched for each cylinder 2, and the downstream end of each independent passage is connected to the outer end of the intake port 12. The surge tank 37 is provided with an intake pressure sensor 38 for detecting the pressure in the intake passage 30 downstream of the throttle valve 36.

  On the other hand, an exhaust passage 40 for discharging burned gas (exhaust gas) from the combustion chamber 6 is connected to the other side of the engine 1. The upstream side of the exhaust passage 40 is constituted by an exhaust manifold having an independent passage branched for each cylinder 2 and connected to the outer end of the exhaust port 13 and a collecting portion where the independent passages gather. In the exhaust passage 40 on the downstream side of the exhaust manifold, a turbine 41 that is rotated by receiving an exhaust flow in order from the upstream side to the downstream side, and a catalytic converter 42 for purifying harmful components in the exhaust, Is arranged.

  The turbine 41 and the compressor 34 in the intake passage 30 constitute a turbocharger 43. When the turbine 41 is rotated by the exhaust flow, the compressor 34 that rotates integrally with the turbine 41 compresses the intake air. And it is supposed to supercharge. The supercharger 43 is not limited to a turbocharger but may be a mechanical supercharger.

  Further, as shown in FIG. 1, the engine 1 is provided with an evaporated fuel control device 50. The evaporative fuel control device 50 communicates a canister 51 filled with an adsorbent (for example, activated carbon) that stores (adsorbs) evaporative fuel in the tank, the fuel tank 23, and the canister 51. From the relief passage 52 for relieving the evaporated fuel staying in the space of the canister 51 to the canister 51, the air release passage 53 extending from the canister 51 and having the tip open to the atmosphere, and the throttle valve 36 in the canister 51 and the intake passage 30. Also, a purge passage 54 that communicates with the downstream portion and supplies evaporated fuel adsorbed by the canister 51 to the intake passage 30, and evaporation that is provided in the purge passage 54 and is supplied from the canister 51 to the intake passage 30. A purge valve 55 for controlling the amount of fuel supplied, and provided in the purge passage 54 closer to the intake passage than the purge valve 55; And a check valve 56 for blocking the flow of air from the air passage to the canister.

  The purge valve 55 is an electromagnetically driven valve that is controlled by a control signal from a powertrain control module 60 described later, and opens and closes the purge passage 54 to open the intake passage 30 from the canister 51 via the purge passage 54. The supply amount of the evaporated fuel supplied to is adjusted.

  The check valve 56 includes a resin ball valve 56a as a valve body for opening and closing the purge passage 54, and a metal valve seat 56b on which the ball valve 56a is seated and separated. The ball valve 56a is urged from the intake passage side to the canister side with respect to the valve seat 56b. In other words, when the pressure on the intake passage side of the purge passage 54 is higher than the pressure on the canister side in the purge passage 54, the check valve 56 is seated on the valve seat 56b so that the ball valve 56a is seated on the intake passage side. The ball valve 56a resists the urging force when the pressure on the canister side in the purge passage 54 is higher than the pressure on the intake passage side in the purge passage 54. By separating from the valve seat 56b, the flow of air from the canister side to the intake passage side is allowed. Therefore, by providing the check valve 56, even if the intake air in the intake passage 30 is pressurized to atmospheric pressure or higher (positive pressure), the intake air does not flow back to the canister 51, and the vaporized fuel enters the atmosphere. Leakage can be prevented.

  In the fuel vapor control apparatus 50 configured as described above, the fuel vapor in the fuel tank 23 is relieved to the canister 51 through the relief passage 52 and is adsorbed by the adsorbent, and only air passes through the air release passage 53 to the atmosphere. Released inside. Further, the evaporated fuel adsorbed by the canister 51 is mixed with purge air flowing in through the air release passage 53 and is supplied from the canister 51 to the intake passage 30 through the purge passage 54 as a purge mixture.

  As schematically shown in FIG. 2, at least the spark plug 16, the injector 20, the high-pressure fuel pump 21, the electric throttle valve 36, the supercharger 43, the purge valve 55, etc. of the engine 1 include a powertrain control module (hereinafter referred to as a powertrain control module). (Referred to as PCM) and receives a control signal from 60. Further, the PCM 60 receives output signals from the air flow sensor 32, the intake air temperature sensor 33, the intake air pressure sensor 38, a crank angle sensor (not shown), a fuel pressure sensor, a throttle sensor, an accelerator opening sensor, etc. Further, an output signal from an atmospheric pressure sensor 71 for detecting the atmospheric pressure and an ignition switch 72 for detecting the operation / stop state of the engine 1 is input.

  That is, the PCM 60 detects the operating state of the engine 1 based on the signals input from the various sensors described above, and in accordance with this, mainly the intake and fuel supply amounts to each cylinder 2 and the mixture to the air-fuel mixture are detected. Control ignition timing. Further, the PCM 60 performs failure diagnosis of the intake pressure sensor 38 after the engine 1 is stopped. Further, during the operation of the engine 1, the PCM 60 controls the purge valve 55 to adjust the supply amount of the evaporated fuel supplied to the intake passage 30 according to the operation state of the engine 1 (hereinafter referred to as purge amount control). In addition, after the engine is stopped, control is performed to open the purge valve 55 in order to open the portion of the purge passage 54 between the purge valve 55 and the check valve 56 to the atmosphere (hereinafter referred to as purge passage opening control). To do. For this reason, the PCM 60 detects at least the operating state of the engine 1 and controls the ignition plug 16 and the like in accordance with this to detect a failure in the operation control unit 60a that controls the operation of the engine 1 and the intake pressure sensor 38. A failure diagnosis unit 60b as an intake pressure sensor failure diagnosis unit to perform, and a purge valve control unit 60c as a purge valve control unit to perform the purge amount control and purge passage opening control.

  Here, the failure diagnosis by the failure diagnosis unit 60b will be described. The failure diagnosis unit 60b performs the operation of the intake pressure sensor 38 and the atmospheric pressure sensor 71 when a predetermined waiting time T1 has elapsed after the engine 1 is stopped. The failure of the intake pressure sensor 38 is diagnosed by comparing the output values. Specifically, the pressure in the intake passage 30 in which the intake pressure sensor 38 is installed is a negative pressure according to the operating state of the engine 1 (specifically, the operating state of the turbocharger 43) immediately after the engine 1 is stopped. Although the pressure is positive, as time passes, the pressure in the intake passage 30 approaches atmospheric pressure, and after a predetermined waiting time T1 has elapsed after the engine 1 is stopped, the pressure in the intake passage 30 becomes atmospheric pressure. (That is, the predetermined waiting time T1 is set to a time when the pressure in the intake passage 30 becomes atmospheric pressure after the engine 1 is stopped). That is, the output value of the intake pressure sensor 38 after the elapse of the predetermined waiting time T1 after the engine 1 stops should be substantially the same as the output value of the atmospheric pressure sensor 71. Therefore, when a predetermined standby time T1 has elapsed after the engine 1 is stopped, the output values of the intake pressure sensor 38 and the atmospheric pressure sensor 71 are compared, so that there is a difference between the output values of the two. It can be determined that the intake pressure sensor 38 has failed. Thus, the failure diagnosis unit 60b diagnoses whether or not the intake pressure sensor 38 has a failure.

  Next, control of the purge valve control unit 60c will be described. In the purge amount control, the purge valve control unit 60c controls the opening degree of the purge valve 55 in accordance with the operating state of the engine 1, and the evaporated fuel adsorbed by the canister 51 within a range that does not adversely affect the air-fuel ratio. The air is supplied to the intake passage 30. In the purge passage opening control, the purge valve control unit 60c controls the purge valve 55 to be fully opened for a predetermined opening time T2 after the engine 1 is stopped. By doing so, the portion of the purge passage 54 between the purge valve 55 and the check valve 56 is opened to the atmosphere via the atmosphere release passage 53. As a result, negative pressure is prevented from remaining in a portion of the purge passage 54 between the purge valve 55 and the check valve 56. As described above, the purge amount control during the operation of the engine 1 and the purge passage opening control after the engine 1 is stopped are configured to be performed by one purge valve control unit 60c. You may comprise so that it may be performed.

  Hereinafter, the evaporated fuel control by the PCM 60 will be described with reference to the flowchart of FIG. The PCM 60 performs the fuel injection control of the injector 20 and the control of the throttle valve 36 in parallel with the evaporated fuel control.

  First, in step S1 after the start, it is determined based on the output signal of the ignition switch 72 whether or not the ignition is turned off. When the ignition is off, that is, when the engine 1 is stopped (YES), the process proceeds to step S2, and the failure diagnosis of the intake pressure sensor 38 and the purge passage opening control are performed as described below. On the other hand, when the ignition is on, that is, when the engine 1 is in operation (NO), the routine proceeds to step S14, where the purge valve 55 is controlled according to the operating state of the engine 1 to perform the purge amount control.

  In step S2, it is determined whether or not a predetermined standby time T1 has elapsed after the engine 1 is stopped. If the standby time T1 has not elapsed (NO), the routine returns and repeats steps S1 and S2 to wait for the standby time T1 to elapse after the engine 1 is stopped.

  If the standby time T1 has elapsed (YES), it is determined in step S3 whether or not the failure diagnosed flag F is 1. If the failure diagnosed flag F is 1 (YES), the process proceeds to step S11. If the failure diagnosis completed flag F is 0 (NO), the process proceeds to step S4. The failure diagnosis completed flag F is a flag for determining whether or not the failure diagnosis of the intake pressure sensor 38 has been executed after the engine 1 has stopped. If the failure diagnosis has already been executed, F = 1. If the fault diagnosis has not been executed yet, F = 0. This failure diagnosis completed flag F is reset to F = 0 every time the ignition is turned on (or every time the ignition is turned off). That is, when the step S3 is executed for the first time after the engine 1 is stopped, the failure diagnosis flag F is 0 because the failure diagnosis of the intake pressure sensor 38 has not been executed yet, and the process proceeds to step S4.

  In the following steps S4 to S10, failure diagnosis of the intake pressure sensor 38 is performed by the failure diagnosis unit 60b. First, in step S4, the output value P1 of the intake pressure sensor is read. Subsequently, in step S5, the output value P2 of the atmospheric pressure sensor 71 is read. In step S6, a pressure deviation ΔP (= P1-P2) that is a deviation between the output value P1 of the intake pressure sensor and the output value P2 of the atmospheric pressure sensor 71 is calculated, and in step S7, the pressure deviation ΔP is predetermined. It is determined whether or not the value is larger than α. As a result, if the pressure deviation ΔP is larger than the predetermined value α (YES), it is diagnosed in step S8 that the intake pressure sensor 38 has failed, while the pressure deviation ΔP is equal to or smaller than the predetermined value α (NO). In step S9, the intake pressure sensor 38 is diagnosed as normal. These diagnostic results are stored in the memory of the PCM 60, etc., and when it is diagnosed that the intake pressure sensor 38 is out of order, an alarm means such as a warning lamp provided on an instrument panel (not shown) alerts the occupant. This is notified.

  When the failure diagnosis of the intake pressure sensor 38 is executed, the failure diagnosis completed flag F is set to 1 in step S10. Then return.

  If the process returns after executing the fault diagnosis of the intake pressure sensor 38, the process proceeds from step S1 to step S3, and the process proceeds to step S11 assuming that the fault diagnosed flag F is 1 in step S3.

  In the following steps S11 to S13, the purge passage opening control is performed by the purge valve control unit 60c. First, in step S11, the purge valve 55 is fully opened. Next, after the purge valve 55 is fully opened in step S12, it is determined whether or not a predetermined opening time T2 has elapsed. When the opening time T2 has not elapsed (NO), the routine returns and repeats steps S1 to S3, S11, and S12 to wait for the opening time T2 to elapse after the purge valve 55 is fully opened. When the opening time T2 has elapsed (YES), the purge valve 55 is fully closed in step S13. Thereafter, the process proceeds to the end, and the PCM 60 is shut down.

  Thus, when the engine 1 is stopped, the purge valve 55 is fully opened for the opening time T2 after the failure diagnosis of the intake pressure sensor 38 is executed, and the portion of the purge passage 54 between the purge valve 55 and the check valve 56 is brought to the atmosphere. Opened.

  Therefore, according to the first embodiment, after the engine 1 is stopped, the purge valve 55 is fully opened for a predetermined opening time T2, so that the portion between the purge valve 55 and the check valve 56 in the purge passage 54 is opened to the atmosphere. Therefore, it is possible to prevent the negative pressure from remaining in the portion. As a result, the ball valve 56a of the check valve 56 is prevented from being pressed more than necessary against the valve seat 56b due to negative pressure, and even if the temperature of the check valve 56 becomes high, the ball valve 56a It is possible to prevent the check valve 56 from malfunctioning due to melting and adhering to the valve seat 56b.

  Further, by releasing the portion of the purge passage 54 between the purge valve 55 and the check valve 56 to the atmosphere after the failure diagnosis of the intake pressure sensor 38 is performed, the intake air is discharged from the purge passage 54 until the failure diagnosis is completed. Air is prevented from flowing into the passage 30. As a result, the pressure fluctuation of the intake passage 30 during the failure diagnosis can be suppressed as much as possible, and the failure diagnosis of the intake pressure sensor 38 can be performed accurately.

<< Embodiment 2 >>
Subsequently, Embodiment 2 of the present invention will be described. The second embodiment is different from the first embodiment in the purge passage opening control. That is, in the first embodiment, the purge passage opening control is always performed after the engine 1 is stopped and the failure diagnosis of the intake pressure sensor 38 is performed. In the second embodiment, the check valve 56 is at a high temperature. The purge passage opening control is performed only at the time.

  The purge passage opening control according to the second embodiment will be mainly described below. In the second embodiment, as shown in FIG. 4, step S15 is added separately between steps S3 and S11 in the flowchart shown in FIG. Specifically, if it is determined in step S3 that the failure diagnosis of the intake pressure sensor 38 has been performed (YES), the process proceeds to step S15 instead of immediately proceeding to step S11. In this step S15, based on the output value of the intake air temperature sensor 33, it is determined whether or not the intake air temperature is higher than a predetermined temperature. If the intake air temperature is higher than the predetermined temperature (YES), it can be determined that the ambient temperature around the engine 1 is high and the temperature of the check valve 56 is also high, so the ball valve 56a of the check valve 56 is high. In order to prevent the valve seat 56b from sticking, the process proceeds to step S11 where the purge valve 55 is fully opened. Since the flow after step S11 is the same as that of the said embodiment, description is abbreviate | omitted. On the other hand, when the intake air temperature is lower than the predetermined temperature (NO), the ambient temperature around the engine 1 is low and the temperature of the check valve 56 is not so high that the ball valve 56a and the valve seat 56b are fixed. Since the determination can be made, the process proceeds to the end without performing full opening control of the purge valve 55. Thus, by performing the purge valve opening control only when the temperature of the check valve 56 (the temperature related to the temperature of the check valve 56) is high, the possibility that the ball valve 56a and the valve seat 56b are fixed is low. Sometimes the purge valve 55 is prevented from being fully opened. As a result, the operation frequency of the purge valve 55 can be suppressed, and the durability of the purge valve 55 can be improved. That is, the predetermined temperature is a temperature at which the ball valve 56a melts and adheres to the valve seat 56b when the ball valve 56a is pressed more than necessary against the valve seat 56b by the negative pressure in the purge passage 54. Set it to.

  In the second embodiment, the intake air temperature sensor 33 for detecting the intake air temperature is used as the temperature detection means for detecting the temperature related to the temperature of the check valve 56. However, the present invention is not limited to this. For example, a temperature sensor attached to the housing of the check valve 56 may be employed. In addition, any means capable of detecting a temperature related to the temperature of the check valve 56 can be adopted.

<< Other Embodiments >>
The present invention may be configured as follows with respect to the embodiment. That is, in the first and second embodiments, the ball valve 56a and the valve seat 56b are employed as the check valve 56, but are not limited thereto. For example, a check valve having a disk valve may be used, and any check valve may be used as long as it has a valve body and a valve seat on which the valve body is seated and separated and allows fluid to flow only in one direction. Can be adopted.

  The ball valve 56a is made of resin, and the valve seat 56b is made of metal, but is not limited thereto. For example, the ball valve 56a may be made of metal and the valve seat 56b may be made of resin, or both may be made of resin. Further, the present invention can be applied if the valve seat and / or the valve seat constituting the check valve is not limited to resin, but can be melted and fixed when the temperature becomes high. Thus, it is possible to prevent the valve body and the valve seat from being melted and fixed due to the negative pressure remaining in the purge passage 54 after the engine is stopped. Further, the valve seat and / or the material that melts the valve seat due to heat is not limited, and the negative pressure remaining in the purge passage 54 causes the valve body to be pressed against the valve seat more than necessary. Therefore, the present invention can be applied to prevent such problems.

  As described above, the present invention can prevent the check valve from causing problems due to the negative pressure generated in the purge passage. Therefore, the check valve is provided between the purge valve and the intake passage in the purge passage. The present invention is useful for an evaporated fuel control device for a supercharged engine.

It is the schematic of the engine with a supercharger which employ | adopted the evaporative fuel control apparatus which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of an evaporative fuel control apparatus. It is a flowchart figure which shows the operation | movement procedure of an evaporative fuel control apparatus. It is a flowchart which shows a part of operation | movement procedure of the fuel vapor control apparatus which concerns on other embodiment.

Explanation of symbols

23 Fuel tank 30 Intake passage 33 Intake temperature sensor (temperature detection means)
38 Intake pressure sensor 51 Canister 54 Purge passage 55 Purge valve 56 Check valve 56a Ball valve (valve element)
56b Valve seat 60b Failure diagnosis unit (intake pressure sensor failure diagnosis means)
60c Purge valve control unit (purge valve control means)
71 Atmospheric pressure sensor

Claims (4)

A canister for storing the evaporated fuel generated in the fuel tank; a purge passage for communicating the canister and the intake passage; and supplying the evaporated fuel stored in the canister to the intake passage; and provided in the purge passage. A purge valve for controlling a supply amount of the evaporated fuel supplied from the canister to the intake passage; a valve body; and a valve seat on which the valve body is seated; and the intake passage side of the purge passage with respect to the purge valve When the pressure on the intake passage side in the purge passage is higher than the pressure on the canister side, the valve body is seated on the valve seat so that the air flow from the intake passage to the canister An evaporative fuel control device for a supercharged engine having a check valve for shutting off
An evaporative fuel control device for a supercharged engine, further comprising purge valve control means for opening the purge valve for a predetermined opening time after the engine is stopped. The evaporated fuel control device for a supercharged engine according to claim 1,
An intake pressure sensor provided in the intake passage for detecting the intake pressure of the intake passage;
An intake pressure sensor failure diagnosing means for performing a failure diagnosis of the intake pressure sensor when a predetermined standby time has elapsed after the engine is stopped;
The evaporated fuel control device for an engine with a supercharger, wherein the purge valve control means opens the purge valve for the opening time after the failure diagnosis by the intake pressure sensor failure diagnosis means is executed. The evaporative fuel control device for an engine with a supercharger according to claim 2,
It further includes an atmospheric pressure sensor that detects atmospheric pressure,
The intake pressure sensor failure diagnosing means performs failure diagnosis of the intake pressure sensor based on a difference between a detected value of the intake pressure sensor and a detected value of the atmospheric pressure sensor. Evaporative fuel control device. The evaporated fuel control device for a supercharged engine according to claim 1,
Temperature detecting means for detecting a temperature related to the temperature of the check valve;
The purge valve control means opens the purge valve for the opening time when the temperature detected by the temperature detection means is higher than a predetermined temperature, and the evaporated fuel control apparatus for a supercharged engine .

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