JP2006057526A - Failure diagnosis device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the accuracy of diagnosing a failure of a supercharger of an engine with the supercharger. <P>SOLUTION: When a throttle valve is closed during the operation of the engine, an air bypass valve (ABV) in an intake bypass line for bypassing a compressor of the supercharger is temporarily opened for releasing supercharging pressure between the compressor and the throttle valve to prevent surging. In this case, a variation in the rotating speed of the compressor is detected before and after changing over the air bypass valve from an open position to a close position, and the presence or not of the failure of the supercharger is diagnosed in accordance with the variation of the rotating speed of the compressor. Herein, a correlation exists between the rotating speed of the compressor and each of the supercharging pressure, intake pipe pressure and an intake air amount, and so the rotating speed of the compressor can be estimated in accordance with at least one of the supercharging pressure, the intake pipe pressure and the intake air amount. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a failure diagnosis device for a supercharger-equipped internal combustion engine having a function of diagnosing whether or not a turbocharger (turbocharger) has failed.

  As a conventional technique for diagnosing the presence or absence of a failure of a supercharger mounted on a vehicle, for example, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 3-23320), a supercharger that detects the rotation speed of the supercharger A turbo speed sensor is provided, and whether the turbocharger speed detected by the turbocharger speed sensor is within the appropriate speed range set according to the engine operating condition. There is a thing to judge.

Alternatively, as shown in Patent Document 2 (Japanese Utility Model Publication No. 4-125635), a supercharging pressure sensor for detecting a compressor discharge pressure (supercharging pressure) of the supercharger and an exhaust pressure at the inlet of the exhaust turbine are detected. There is an exhaust pressure sensor that diagnoses the presence or absence of a turbocharger failure based on the relationship between the supercharging pressure detected by these two sensors and the exhaust pressure.
JP-A-3-23320 (second page, etc.) Japanese Utility Model Publication No. 4-125635 (first page, etc.)

  However, as in Patent Document 1, whether the turbocharger rotation speed detected by the turbocharger rotation speed sensor is within an appropriate rotation speed range set according to the engine operating state is normal / In the method of determining failure, the relationship between the engine operating state and the turbocharger rotational speed varies considerably due to turbo lag, etc., so it is necessary to set the appropriate rotational speed range to some extent in consideration of this variation. There is a drawback that the diagnostic accuracy is deteriorated. Moreover, in the operation region where the supercharging pressure is generated, the supercharger rotation speed becomes very high, so it is difficult to accurately detect the supercharger rotation speed, and the supercharger rotation speed sensor. For this signal processing, a very high-speed calculation process is required, and there is a disadvantage that the calculation load of the CPU becomes too large.

  Further, as disclosed in Patent Document 2, in the method of diagnosing the presence or absence of a turbocharger failure from the relationship between the supercharging pressure and the exhaust pressure detected by the supercharging pressure sensor and the exhaust pressure sensor, the supercharging pressure and the exhaust pressure are determined. Therefore, there is a disadvantage in that the failure diagnosis accuracy is deteriorated accordingly. In addition, since it is necessary to provide a new exhaust pressure sensor for failure diagnosis, there is a problem that the cost increases.

  The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a fault diagnosis device for an internal combustion engine with a supercharger that can improve the fault diagnosis accuracy of the supercharger. There is.

  In order to achieve the above object, an invention according to claim 1 includes a supercharger that supercharges intake air by driving a compressor provided in an intake passage by an exhaust turbine provided in an exhaust passage of an internal combustion engine; An intake bypass passage that bypasses the upstream side and the downstream side of the compressor upstream of the throttle valve of the intake passage, an air bypass valve that opens and closes the intake bypass passage, and immediately after the throttle valve is closed In a failure diagnosis apparatus for an internal combustion engine with a supercharger, comprising: a control means for controlling to release a supercharging pressure between the compressor and the throttle valve by temporarily opening an air bypass valve; Compressor rotation speed detecting means for detecting or estimating the air bypass valve is closed from the open position. Is obtained as diagnosed by the failure diagnosis means the presence or absence of a failure of the supercharger based on the amount of change in the compressor rotational speed before and after switching the location.

  It is known that when the internal combustion engine with a supercharger is operated and the throttle valve is closed and the intake passage on the discharge side of the compressor is closed, surging occurs and vibration and noise are generated. In order to prevent this surging, an intake bypass passage for bypassing the upstream side and the downstream side of the compressor is provided. As shown in FIG. 2, the air bypass valve in the intake bypass passage is temporarily set immediately after the throttle valve is closed. To release the supercharging pressure between the compressor and the throttle valve.

  As shown in FIG. 2, when the air bypass valve is opened while the throttle valve is closed, the rotation state of the compressor becomes free and the compressor rotation speed decreases rapidly. When is closed, the compressor rotational speed increases toward the final convergent rotational speed during idle operation. The compressor rotation speed immediately before the throttle valve is closed varies greatly depending on the engine operating state such as the throttle opening, but when the throttle valve is closed and the air bypass valve is opened, the compressor rotation state becomes free. Therefore, the compressor rotation speed rapidly decreases to the minimum rotation speed. If the turbocharger is normal, the compressor rotation speed changes with good response according to the opening and closing of the air bypass valve. However, if the turbocharger fails, the change in the compressor rotation speed is small even if the air bypass valve is opened and closed. .

  The present invention pays attention to the change characteristic of the compressor rotation speed accompanying the opening and closing operation of the air bypass valve, and the compressor rotation speed before and after switching the air bypass valve from the open position to the closed position when the throttle valve is closed. The presence or absence of a turbocharger failure is diagnosed based on the amount of change. Before and after switching the air bypass valve from the open position to the closed position, the throttle valve is closed, so the turbocharger can be diagnosed during idle operation when the engine operating state is stable. Failure diagnosis accuracy can be improved.

  In addition, since the present invention performs failure diagnosis of the turbocharger using a low rotation region that is equal to or less than the rotation speed during idle operation, the rotation speed sensor can detect the rotation speed of the compressor at the time of failure diagnosis. The calculation load of the CPU for signal processing of the sensor can be reduced as compared with Patent Document 1.

  Therefore, the present invention may be configured such that the compressor rotational speed is detected by the rotational speed sensor at the time of failure diagnosis. However, as in claim 2, the compressor rotational speed is determined based on the supercharging pressure detected by the supercharging pressure detecting means. The compressor rotational speed may be estimated based on the intake pipe pressure detected by the intake pipe pressure detecting means, or the intake air amount may be estimated as in claim 4. The compressor rotation speed may be estimated based on the intake air amount detected by the detection means.

  As shown in FIG. 2, since there is a correlation between the compressor rotation speed and the supercharging pressure, the intake pipe pressure, and the intake air amount, the compressor is calculated from any of the supercharging pressure, the intake pipe pressure, and the intake air amount. It is possible to estimate the rotational speed. As a result, the compressor rotation speed can be estimated using the signal of an existing sensor provided for engine control or supercharging pressure control. It is possible to satisfy the demand for cost reduction and to reduce the calculation load of the CPU as compared with the case of using the rotation speed sensor.

  Further, as in claim 5, a value obtained by averaging the compressor rotational speed detected or estimated by the compressor rotational speed detecting means during a predetermined period before and after switching the air bypass valve from the open position to the closed position is used. Thus, it is preferable to calculate the amount of change in the compressor rotation speed. In this way, even if noise or intake pulsation waveforms are superimposed on the output signal of the compressor rotation speed detecting means (a sensor for detecting the boost pressure, intake pipe pressure, intake air amount), the effect is almost eliminated. It is possible to improve the detection / estimation accuracy of the compressor rotation speed.

  Further, as in claim 6, the compressor rotational speed immediately before switching the air bypass valve from the open position to the closed position, and the rotational speed at which the compressor rotational speed finally converges after switching the air bypass valve to the closed position (idle The amount of change in the compressor rotation speed is calculated using the compressor rotation speed at the time when a predetermined time corresponding to the standard response time until the rotation speed increases to 50 to 90% of the rotation speed (convergence rotation speed during operation). It is good to do. In this way, it is possible to accurately detect the amount of change in the compressor rotation speed, which is a measure of responsiveness in which the compressor rotation speed increases from the minimum rotation speed toward the convergence rotation speed during idle operation. By comparing the amount of change in speed with the determination value, it is possible to accurately diagnose the failure of the turbocharger.

  In this case, as in claims 7 and 8, the difference or ratio between the compressor rotational speeds at two points before and after the air bypass valve is switched from the open position to the closed position may be used as the amount of change in the compressor rotational speed. . If the ratio of the compressor rotation speed is used, it is possible to remove the influence of output (detection value) deviation due to aging of the sensor or the like.

  Hereinafter, two Examples 1 and 2, which embody the best mode for carrying out the present invention, will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 (intake passage) of the engine 11 that is an internal combustion engine, and an air flow meter 14 (intake air amount detection means) that detects the intake air amount downstream of the air cleaner 13. ) Is provided. A downstream side of the air flow meter 14 is provided with a compressor 27 of an exhaust turbine supercharger 25 described later and an intercooler 31 that cools intake air pressurized by the compressor 27. On the downstream side of the intercooler 31, a supercharging pressure sensor 39 (supercharging pressure detecting means) for detecting the supercharging pressure, a throttle valve 15 whose opening is adjusted by a motor or the like, and a throttle opening for detecting the throttle opening. A degree sensor 16 is provided.

  Further, a surge tank 17 is provided on the downstream side of the throttle valve 15, and an intake pipe pressure sensor 18 (intake pipe pressure detecting means) for detecting the intake pipe pressure is provided in the surge tank 17. The surge tank 17 is provided with an intake manifold 19 for introducing air into each cylinder of the engine 11, and a fuel injection valve 20 for injecting fuel is attached in the vicinity of the intake port of the intake manifold 19 of each cylinder. Yes. A spark plug 21 is attached to the cylinder head of the engine 11 for each cylinder, and an air-fuel mixture in each cylinder is ignited by spark discharge of each spark plug 21.

  On the other hand, an air-fuel ratio sensor 24 for detecting the air-fuel ratio of the exhaust gas is provided in the exhaust pipe 22 (exhaust passage) of the engine 11, and a three-way catalyst for purifying the exhaust gas is provided downstream of the air-fuel ratio sensor 24. The catalyst 23 is provided.

  An exhaust turbine supercharger 25 is mounted on the engine 11. In the supercharger 25, an exhaust turbine 26 is disposed between the air-fuel ratio sensor 24 and the catalyst 23 in the exhaust pipe 22, and a compressor 27 is disposed between the air flow meter 14 and the throttle valve 15 in the intake pipe 12. Is arranged. In the supercharger 25, an exhaust turbine 26 and a compressor 27 are connected, and the exhaust turbine 26 is rotationally driven by the kinetic energy of exhaust gas, whereby the compressor 27 is rotationally driven to supercharge intake air. . The catalyst 23 may be arranged between the air-fuel ratio sensor 24 and the exhaust turbine 26.

  Further, the intake pipe 12 is provided with an intake bypass passage 28 that bypasses the upstream side and the downstream side of the compressor 27 on the upstream side of the throttle valve 15. The intake bypass passage 28 is opened and closed in the middle of the intake bypass passage 28. An air bypass valve (hereinafter referred to as “ABV”) 29 is provided. The ABV 29 is configured such that the opening / closing operation of the ABV 29 is controlled by controlling the ABV vacuum switching valve 30.

  On the other hand, the exhaust pipe 22 is provided with an exhaust bypass passage 32 that bypasses the upstream side and the downstream side of the exhaust turbine 26, and a waste gate valve (hereinafter referred to as a waste gate valve) that opens and closes the exhaust bypass passage 32 in the middle of the exhaust bypass passage 32. 33 (denoted as “WGV”). The WGV 33 is configured such that the opening degree of the WGV 33 is controlled by controlling the WGV vacuum switching valve 34 and the diaphragm actuator 35.

  A cooling water temperature sensor 36 that detects the cooling water temperature and a crank angle sensor 37 that outputs a pulse signal each time the crankshaft of the engine 11 rotates a predetermined crank angle are attached to the cylinder block of the engine 11. Based on the output signal of the crank angle sensor 37, the crank angle and the engine speed are detected.

  Outputs of these various sensors are input to an engine control circuit (hereinafter referred to as “ECU”) 38. The ECU 38 is mainly composed of a microcomputer, and controls the fuel injection amount and the ignition timing by executing various engine control routines stored in a built-in ROM (storage medium), and the opening of the WGV 33. By controlling the amount of exhaust gas supplied to the exhaust turbine 26, the rotation of the exhaust turbine 26 and the compressor 27 is controlled to control the supercharging pressure.

  Further, the ECU 38 executes a failure diagnosis routine of FIG. 4 stored in the ROM during engine operation at a predetermined cycle, thereby executing a failure diagnosis of the supercharger 25. Hereinafter, a failure diagnosis method for the supercharger 25 will be described with reference to the time charts of FIGS.

  Normally, the engine is operated with the ABV 29 closed. However, as shown in FIG. 2, when the throttle valve 15 is fully closed, the ABV 29 is temporarily opened and the intake bypass passage 28 is temporarily opened. Thus, the supercharging pressure between the compressor 27 and the throttle valve 15 is released to prevent surging. When the ABV 29 is opened while the throttle valve 15 is closed, the rotation state of the compressor 27 becomes free and the compressor rotation speed decreases rapidly. Thereafter, when the ABV 29 is closed, the compressor rotation speed is increased. It rises toward the final convergence rotation speed during idling. The compressor rotational speed immediately before the throttle valve 15 is closed varies greatly depending on the engine operating state such as the throttle opening, but when the throttle valve 15 is closed and the ABV 29 is opened, the rotational state of the compressor 27 is free. Therefore, the compressor rotation speed rapidly decreases to the minimum rotation speed. If the turbocharger 25 is normal, the compressor rotation speed changes with good response according to the opening / closing of the ABV 29. However, if the turbocharger 25 breaks down, the change in the compressor rotation speed becomes small even if the ABV 29 is opened / closed.

  In the first embodiment, paying attention to the change characteristic of the compressor rotational speed associated with the opening / closing operation of the ABV 29, when the throttle valve 15 is closed, the change in the compressor rotational speed before and after switching the ABV 29 from the open position to the closed position. The amount (the rise responsiveness of the compressor rotation speed) is detected, and the presence or absence of a failure of the turbocharger 25 is diagnosed based on the amount of change in the compressor rotation speed. Before and after switching the ABV 29 from the open position to the closed position, the throttle valve 15 is closed, so that the failure diagnosis of the supercharger 25 can be performed during the idle operation in which the engine operating state is stable.

  In addition, in the first embodiment, since the failure diagnosis of the turbocharger 25 is performed using a low rotation region that is equal to or lower than the rotation speed during idle operation, the compressor rotation speed may be detected by the rotation speed sensor during the failure diagnosis. The calculation load of the ECU 38 for the signal processing of the rotation speed sensor can be reduced as compared with the above-mentioned Patent Document 1.

  Therefore, the present invention may be configured to detect the compressor rotational speed with the rotational speed sensor at the time of failure diagnosis. However, in the first embodiment, the supercharging pressure detected by the supercharging pressure sensor 39 and the intake pipe pressure sensor 18 are used. The compressor rotational speed is estimated based on at least one of the detected intake pipe pressure and the intake air amount detected by the air flow meter 14.

  As shown in FIG. 2, since there is a correlation between the compressor rotation speed and the supercharging pressure, the intake pipe pressure, and the intake air amount, the compressor is calculated from any of the supercharging pressure, the intake pipe pressure, and the intake air amount. It is possible to estimate the rotational speed. As a result, the compressor rotational speed can be estimated using signals from the existing supercharging pressure sensor 39, intake pipe pressure sensor 18, and air flow meter 14 provided for engine control and supercharging pressure control. A rotation speed sensor for detecting the compressor rotation speed is not required.

  In the first embodiment, when detecting the amount of change in the compressor rotation speed before and after switching the ABV 29 from the open position to the closed position, as shown in FIG. 3, the timing immediately before switching the ABV 29 from the open position to the closed position is shown. Compressor rotation speed NC (t1) at t1 and standard until the compressor rotation speed increases to 50 to 90% (for example 63%) of the convergence rotation speed NCclosed during idle operation after the ABV 29 is switched to the closed position The change amount [NC (t2) −NC (t1)] of the compressor rotation speed is calculated using the compressor rotation speed NC (t2) at the time t2 when a predetermined time T2 corresponding to a typical response time has elapsed. Yes. In this way, the amount of change in the compressor rotational speed [NC (t2) −NC (t1)], which is a measure of the responsiveness that the compressor rotational speed increases from the minimum rotational speed toward the convergent rotational speed NCclosed during idle operation. Can be detected with high accuracy.

  However, in the present invention, when a predetermined time corresponding to a standard response time elapses until the compressor rotation speed increases to a rotation speed set to 50% or less or 90% or more of the convergence rotation speed NCclosed during idle operation. Needless to say, the compressor rotational speed in the above may be used.

  The failure diagnosis of the supercharger 25 described above is executed as follows by the failure diagnosis routine of FIG. The failure diagnosis routine of FIG. 4 is executed at a predetermined cycle by the ECU 38 during engine operation, and plays a role as failure diagnosis means in the claims. When this routine is started, it is first determined in step 101 whether or not the ABV 29 is open. If it is determined that the ABV 29 is open, the process proceeds to step 102 to perform processing for measuring the ABV open time. Do.

  Thereafter, the routine proceeds to step 103, where it is determined whether or not the ABV 29 is closed at a timing t1 immediately before the ABV 29 is closed, depending on whether or not the ABV opening time exceeds a predetermined time T1, and the ABV opening time exceeds the predetermined time T1. If it is determined that there is not (no timing t1 immediately before the ABV 29 is closed), this routine is terminated without performing the subsequent processing.

  Thereafter, when this routine is started when the ABV opening time exceeds the predetermined time T1 and reaches the timing t1 immediately before the ABV 29 is closed, it is determined as “Yes” in Step 103, and the process proceeds to Step 104. , The compressor rotational speed NC (t1) at the timing t1 immediately before the ABV 29 is closed is detected. At this time, based on at least one of the supercharging pressure detected by the supercharging pressure sensor 39, the intake pipe pressure detected by the intake pipe pressure sensor 18, and the intake air amount detected by the air flow meter 14, a map or the like is used. Estimate the compressor rotation speed NC (t1). Further, the compressor rotational speed NC (t1) may be averaged over a predetermined period (predetermined time around t1) until the ABV 29 is closed. In this averaging process, detection values (estimated values) within a predetermined period may be integrated, and the integrated value may be divided by the number of integrations to obtain an average value. It may be used.

  As described above, after detecting the compressor rotational speed NC (t1) at the timing t1 immediately before the ABV 29 is closed, the routine proceeds to step 105, and the ABV closing flag is set to "1" which means that the ABV 29 is closed. This routine is terminated.

  When this routine is started after the ABV 29 is closed, “No” is determined in Step 101 and the process proceeds to Step 106 to determine whether or not the ABV closing flag is “1”, and the ABV closing flag is “1”. If so, the process proceeds to step 107 to perform processing for measuring the ABV closing time.

  After this, the routine proceeds to step 108, where the ABV closing time is a predetermined time corresponding to a standard response time until the compressor speed increases to 50 to 90% (for example, 63%) of the convergence speed NCclosed during idling operation. It is determined whether or not T2 has been exceeded. If the ABV closing time has not exceeded the predetermined time T2, this routine is terminated without performing the subsequent processing.

  Thereafter, when this routine is started at the time point t2 when the ABV closing time exceeds the predetermined time T2, it is determined "Yes" at step 108, and the routine proceeds to step 109, where the ABV closing time exceeds the predetermined time T2. The compressor rotational speed NC (t2) at time t2 is detected by the same method as in step 104. The processing in these steps 104 and 109 serves as a compressor rotation speed detecting means in the claims.

In the next step 110, the difference between the compressor rotational speeds NC (t1) and NC (t2) at the two time points t1 and t2 is calculated as the compressor rotational speed change amount ΔNC.
ΔNC = NC (t2) −NC (t1)

Thereafter, the process proceeds to step 111, where the compressor rotation speed change amount ΔNC is compared with a predetermined determination value. If the compressor rotation speed change amount ΔNC is larger than the determination value, the process proceeds to step 112, where the supercharger 25 is normal. If it is determined that the compressor rotational speed change amount ΔNC is equal to or smaller than the determination value, it is determined that the turbocharger 25 is in failure, and the failure information is stored in a rewritable nonvolatile memory such as a backup RAM of the ECU 38. At the same time, a warning lamp is lit or a warning is displayed on the display of the instrument panel of the driver's seat.
After determining whether or not the turbocharger 25 has failed in this way, the routine proceeds to step 114, where the ABV closing flag is reset, and this routine is terminated.

  According to the first embodiment described above, the ABV 29 is opened when the throttle valve 15 is closed by paying attention to the change characteristic of the compressor rotation speed accompanying the opening / closing operation of the ABV 29 as shown in FIGS. The amount of change in the compressor rotation speed before and after switching from the position to the closed position is detected, and the presence or absence of a failure of the turbocharger 25 is diagnosed based on the amount of change in the compressor rotation speed, so that the engine operating state is stable. The failure diagnosis of the supercharger 25 can be performed during idle operation, and the failure diagnosis accuracy of the supercharger 25 can be improved.

  Moreover, in the first embodiment, as shown in FIG. 2, paying attention to the fact that there is a correlation among the compressor rotation speed, the supercharging pressure, the intake pipe pressure, and the intake air amount, Since the compressor rotational speed is estimated based on at least one of the pipe pressure and the intake air amount, the existing supercharging pressure sensor 39 and intake pipe pressure sensor 18 provided for engine control and supercharging pressure control are provided. The compressor rotational speed can be estimated by using the signal from the air flow meter 14, and the rotational speed sensor for detecting the compressor rotational speed is not required, so that the demand for cost reduction can be satisfied. There is also an advantage that can be reduced.

  In the first embodiment, the difference [NC (t2) −NC (t1)] between the compressor rotational speeds NC (t1) and NC (t2) at two time points t1 and t2 before and after switching the ABV 29 from the open position to the closed position. Although it is calculated as the compressor rotation speed change amount ΔNC, in the second embodiment of the present invention, by executing the failure diagnosis routine of FIG. 5, two time points t1, before and after switching the ABV 29 from the open position to the closed position. The ratio [NC (t2) / NC (t1)] of the compressor rotation speed NC (t1) and NC (t2) at t2 is calculated as the compressor rotation speed change amount ΔNC (step 110a). The other processing is the same as the processing of each step of the failure diagnosis routine of FIG. 4 described in the first embodiment.

  As in the second embodiment, the ratio of the compressor rotational speeds NC (t1) and NC (t2) at two time points t1 and t2 before and after switching the ABV 29 from the open position to the closed position [NC (t2) / NC (t1) ] As the compressor rotational speed change amount ΔNC, there is an advantage that the influence of the deviation of the output (detected value) due to the secular change or the like of the sensor used for estimating the compressor rotational speed can be eliminated.

It is a schematic block diagram of the whole engine control system which shows Example 1 of this invention. It is a time chart explaining the behavior of the ABV operation signal, the compressor rotation speed, the intake air amount, the supercharging pressure, and the intake pipe pressure after the throttle opening is fully closed. It is a time chart explaining the method of detecting the variation | change_quantity of the compressor rotational speed before and behind switching an ABV (air bypass valve) from an open position to a closed position. 3 is a flowchart illustrating a flow of processing of a failure diagnosis routine according to the first embodiment. 6 is a flowchart illustrating a flow of processing of a failure diagnosis routine according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Intake pipe (intake passage), 14 ... Air flow meter (intake air amount detection means), 15 ... Throttle valve, 18 ... Intake pipe pressure sensor (intake pipe pressure detection means), 20 ... Fuel injection valve, 21 ... ignition plug, 22 ... exhaust pipe (exhaust passage), 24 ... air-fuel ratio sensor, 25 ... supercharger, 26 ... exhaust turbine, 27 ... compressor, 28 ... intake bypass passage, 29 ... ABV (air) (Bypass valve), 32 ... exhaust bypass passage, 33 ... WGV (waste gate valve), 38 ... ECU (fault diagnosis means, compressor rotation speed detection means), 39 ... supercharging pressure sensor (supercharging pressure detection means)

Claims (8)

A turbocharger that drives a compressor provided in an intake passage by an exhaust turbine provided in an exhaust passage of an internal combustion engine to supercharge intake air; and an upstream side of the compressor upstream of a throttle valve of the intake passage And an air bypass valve that opens and closes the air intake bypass passage, and immediately after the throttle valve is closed, the air bypass valve is temporarily opened to In the failure diagnosis device for an internal combustion engine with a supercharger that controls so as to release the supercharging pressure between the throttle valve,
Compressor rotation speed detecting means for detecting or estimating the compressor rotation speed;
A turbocharger comprising failure diagnosis means for diagnosing the presence or absence of a failure of the turbocharger based on a change amount of a compressor rotation speed before and after switching the air bypass valve from an open position to a closed position Fault diagnosis device for internal combustion engine with a valve. A supercharging pressure detecting means for detecting a supercharging pressure between the compressor and the throttle valve;
2. The failure diagnosis apparatus for an internal combustion engine with a supercharger according to claim 1, wherein the compressor rotation speed detection means estimates a compressor rotation speed based on a boost pressure detected by the boost pressure detection means. . An intake pipe pressure detecting means for detecting an intake pipe pressure downstream of the throttle valve;
2. The failure diagnosis apparatus for an internal combustion engine with a supercharger according to claim 1, wherein the compressor rotation speed detection means estimates a compressor rotation speed based on the intake pipe pressure detected by the intake pipe pressure detection means. . Intake air amount detection means for detecting the intake air amount,
2. The failure diagnosis apparatus for an internal combustion engine with a supercharger according to claim 1, wherein the compressor rotation speed detection means estimates a compressor rotation speed based on the intake air amount detected by the intake air amount detection means. .   The failure diagnosis means uses a value obtained by averaging the compressor rotation speed detected or estimated by the compressor rotation speed detection means during a predetermined period before and after switching the air bypass valve from the open position to the closed position. The failure diagnosis device for an internal combustion engine with a supercharger according to any one of claims 1 to 4, wherein a change amount of the compressor rotation speed is calculated.   The failure diagnosis means includes a compressor rotational speed immediately before switching the air bypass valve from an open position to a closed position, and a rotational speed at which the compressor rotational speed finally converges after the air bypass valve is switched to the closed position. 2. The amount of change in the compressor rotational speed is calculated using a compressor rotational speed at a time when a predetermined time corresponding to a standard response time until the rotational speed reaches 90% is reached. The failure diagnosis device for an internal combustion engine with a supercharger according to any one of claims 1 to 5.   7. The failure diagnosis means uses a difference in compressor rotation speed at two time points before and after switching the air bypass valve from an open position to a closed position as a change amount of the compressor rotation speed. The failure diagnosis device for an internal combustion engine with a supercharger according to any one of the above.   The said failure diagnosis means uses the ratio of the compressor rotational speed at two time points before and after switching the air bypass valve from the open position to the closed position as the amount of change in the compressor rotational speed. The failure diagnosis device for an internal combustion engine with a supercharger according to any one of the above.

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