JP2017057839A - Abnormality diagnostic device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality diagnostic device for an internal combustion engine capable of making an abnormality diagnosis of a supercharger early.SOLUTION: An abnormality diagnostic device for an engine 2 having a supercharger 5 includes: a boost pressure sensor 121 for detecting actual boost pressure into an intake manifold 3a of the engine; a vehicle control section 11 for determining target boost pressure that varies depending on output of the engine; a calculation section 12 for calculating a threshold value used for an abnormality determination of the boost pressure changing toward the target boost pressure on the basis of a preset map; and a determination section 13 for making the abnormality determination on the basis of the threshold value calculated by the calculation section and the actual boost pressure detected by the boost pressure sensor. Along with the change of the target boost pressure determined by the vehicle control section, the calculation section calculates the threshold value used for the abnormality determination of the boost pressure. On the basis of the calculated threshold value, the determination section makes an abnormality diagnosis of the boost pressure of the supercharger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an abnormality diagnosis device for diagnosing abnormality of a supercharger provided in an internal combustion engine.

  In an internal combustion engine, a driving torque is efficiently increased by attaching a supercharger that forcibly increases an intake air amount. Patent Document 1 discloses an abnormality diagnosis device that diagnoses whether or not an actual supercharging pressure (hereinafter referred to as an actual supercharging pressure) by the supercharger exceeds an allowable range from a target supercharging pressure.

JP 2010-106811 A

  However, as shown in FIGS. 12 and 13, for example, when the target supercharging pressure is changed, the actual supercharging pressure Pr reaches the target supercharging pressure Ptarget with a delay from the start of control, and thereafter, overshooting occurs. And stabilize after repeated undershoot. Therefore, the abnormality diagnosis device as described in Patent Document 1 waits until the actual supercharging pressure Pr is stabilized, and then diagnoses whether or not the supercharger is functioning normally. Even if this occurs, it is not possible to immediately determine an abnormality. For this reason, in such an abnormality diagnosis device, it is not possible to detect a supercharging pressure abnormality that would cause a failure at an early stage.

  Such an abnormality diagnosing device can be set so as to diagnose an abnormality without waiting for the actual supercharging pressure to stabilize. However, for example, if the threshold for determining the presence or absence of an abnormality remains as it is, an abnormality is diagnosed by overshooting and undershooting of the actual boost pressure.

  Further, in this abnormality diagnosis device, the threshold value for determining the presence or absence of abnormality can be expanded to such an extent that overshoot and undershoot at the start of the turbocharger start are not diagnosed as occurrence of abnormality. However, in this case, there is a possibility that the abnormality is not diagnosed even though the abnormality occurs in the supercharger.

  Accordingly, an object of the present invention is to provide an abnormality diagnosis device for an internal combustion engine that can perform abnormality diagnosis of a supercharger at an early stage.

  An aspect of the invention of an abnormality diagnosis device for an internal combustion engine that solves the above-described problem is an abnormality diagnosis device for an internal combustion engine that includes a supercharger, wherein the actual supercharging pressure at a predetermined position on the intake passage of the internal combustion engine is determined. A supercharging pressure measuring unit for measuring, a vehicle control unit for determining a target supercharging pressure to be changed according to the output of the internal combustion engine, and a change to the target supercharging pressure based on a preset map An arithmetic unit for calculating a threshold value used for determining an abnormality of the supercharging pressure, an abnormality determination of the supercharging pressure based on the threshold value calculated by the arithmetic unit and the actual supercharging pressure measured by the supercharging pressure measuring unit. And a threshold value used for determining an abnormality of the supercharging pressure that changes toward the target supercharging pressure in accordance with a change in the target supercharging pressure determined by the vehicle control unit. Overrun by the supercharger based on the threshold value calculated by the determination unit. Is configured to perform an abnormality diagnosis of the internal combustion engine performs abnormality determination of the pressure.

  Thus, according to one aspect of the present invention, it is possible to provide an abnormality diagnosis device for an internal combustion engine that can perform abnormality diagnosis of a supercharger at an early stage.

FIG. 1 is a diagram showing an example of a vehicle equipped with an internal combustion engine abnormality diagnosis apparatus according to an embodiment of the present invention, and is a conceptual diagram showing a schematic overall configuration thereof. FIG. 2 is a block diagram illustrating the configuration of an ECM that executes abnormality diagnosis processing. FIG. 3 is a graph for explaining the fluctuation of the actual boost pressure that increases when the boost pressure is changed. FIG. 4 is a graph for explaining the setting of the determination region used when performing an abnormality diagnosis of the increasing supercharging pressure. FIG. 5 is a graph for explaining setting of a determination region different from that in FIG. 4 used when performing an abnormality diagnosis of a rising supercharging pressure. FIG. 6 is a graph for explaining setting of determination areas different from those in FIGS. 4 and 5 that are used when diagnosing an abnormality of the boost pressure that increases. FIG. 7 is a graph showing the entire determination region used when performing an abnormality diagnosis of the increasing supercharging pressure. FIG. 8 is a graph for explaining the fluctuation of the actual boost pressure that decreases when the boost pressure is changed. FIG. 9 is a graph showing the entire determination region used when an abnormality diagnosis of the decreasing supercharging pressure is performed. FIG. 10 is a flowchart for explaining various setting processes in the abnormality diagnosis process. FIG. 11 is a flowchart illustrating a determination process in the abnormality diagnosis process. FIG. 12 is a graph for explaining a problem at the time of abnormality diagnosis of a boost pressure that increases. FIG. 13 is a graph for explaining a problem at the time of abnormality diagnosis of the decreasing supercharging pressure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1-11 is a figure which shows an example of the vehicle carrying the abnormality diagnosis apparatus of the internal combustion engine which concerns on one Embodiment of this invention.

  In FIG. 1, a vehicle 1 is equipped with an internal combustion engine type engine 2 to obtain driving power, and the engine 2 is controlled in an integrated manner by an ECM (Engine Control Module) 10 and is driven under optimum conditions. It has become.

  The engine 2 is an internal combustion engine with a supercharger, and is a so-called direct injection gasoline engine that directly injects fuel pumped from a fuel tank (not shown) by a fuel pump into the combustion chamber 2a. The engine 2 is not limited to the direct injection type, but may be a port injection type, or may be not only a gasoline engine but also an engine of a type such as a diesel engine.

  An intake pipe 3 is connected to the engine 2. An intake passage in the intake pipe 3 communicates with an intake port (not shown) via an intake manifold 3a. The intake air sucked through the intake pipe 3 is sucked into the combustion chamber 2a together with the fuel before combustion.

  An exhaust pipe 4 is connected to the engine 2. An exhaust passage in the exhaust pipe 4 communicates with an exhaust port via an exhaust manifold 4a. The exhaust gas after combustion exhausted from the combustion chamber 2 a is exhausted through the exhaust pipe 4.

  With this configuration, the engine 2 can output power for driving the vehicle 1 by burning the air-fuel mixture in the combustion chamber 2a and moving a piston (not shown) up and down.

  The intake pipe 3 includes an air cleaner 31 for purifying the intake air, a compressor 32 for compressing the intake air, an intercooler 33 for cooling the compressed intake air, a throttle valve 34 for adjusting the flow rate of the intake air, Is provided. The exhaust pipe 4 is provided with an exhaust turbine 42 driven by an exhaust flow, a catalyst, a muffler and the like (not shown).

  The exhaust turbine 42 is connected to the compressor 32 on the intake pipe 3 side. The power of the exhaust turbine 42 driven by the exhaust flow is used as power for the compressor 32 to compress the intake air in the intake pipe 3. The compressor 32 and the exhaust turbine 42 constitute the supercharger 5.

  An exhaust bypass 50 is disposed in the supercharger 5. The exhaust bypass 50 has a wastegate valve 51 that can adjust the exhaust flow to the exhaust turbine 42. The wastegate valve 51 opens and closes the exhaust bypass 50 to adjust the exhaust flow to the exhaust turbine 42 that circulates in the exhaust pipe 4, thereby increasing the pressure of the intake air obtained by supercharging the supercharger 5. The supply pressure can be controlled. The wastegate valve 51 is constituted by, for example, an electromagnetic valve and is controlled to be opened and closed by the ECM 10. For example, the waste gate valve 51 is controlled to be opened and closed by the ECM 10 so as to prevent a malfunction from occurring when it is diagnosed that an abnormal increase in supercharging pressure has occurred by an abnormality diagnosis described later. .

  The turbocharger 5 is provided with an intake bypass 60 including an intake bypass valve 61 that is controlled to open and close by the ECM 10. The intake bypass valve 61 adjusts the intake air flow to the compressor 32 that circulates in the intake pipe 3. The intake bypass valve 61 is controlled to be opened and closed by the ECM 10 so that, for example, the intake air supercharged during deceleration is recirculated to the upstream side of the supercharger 5.

  With this configuration, the engine 2 can adjust the supercharging pressure at which the intake air is pushed into the intake pipe 3 by the supercharger 5.

  In addition, an EGR pipe 7 is connected to the engine 2 so as to communicate between the intake manifold 3a and the exhaust pipe 4. An EGR valve 71 that is controlled to be opened and closed by the ECM 10 is attached to the EGR pipe 7.

  With this configuration, the engine 2 can return a part of the exhaust gas after burning the air-fuel mixture of intake air and fuel into the combustion chamber 2a via the EGR pipe 7, and a high temperature containing unburned air. The exhaust gas can be mixed with fresh air-fuel mixture, and the unburned fuel contained in the exhaust gas can be mixed with the air-fuel mixture. For this reason, the engine 2 can improve the combustion efficiency and reduce harmful substances contained in the exhaust gas before purification by the catalyst.

  The ECM 10 includes, for example, a microcomputer including a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored (set) in the ROM in advance. Signal processing is performed. Various control constants and various maps are stored in advance in the ROM.

  On the input side of the ECM 10, an accelerator sensor 101, a crank angle sensor 102, a cam angle sensor 103, a vehicle speed sensor 104, an air flow meter 111, an intake air temperature sensor 112, an atmospheric pressure sensor 113, a MAP (Manifold Absolute Pressure) sensor 114, a water temperature sensor 115, various sensors such as a supercharging pressure sensor (supercharging pressure measuring unit) 121 are connected.

  The accelerator sensor 101 detects the opening of the throttle valve 34 that is linked to the amount of depression of an accelerator pedal (not shown) by the driver as the accelerator opening. The crank angle sensor 102 detects the rotation angle of the crankshaft that is rotated by the vertical movement of the piston of the engine 2. An intake port of the intake port and an exhaust port of the exhaust port are opened in the combustion chamber 2a of the engine 2, and the cam angle sensor 103 opens and closes the intake valve and the exhaust valve that open and close the intake port and the exhaust port. Detect the camshaft rotation angle. The vehicle speed sensor 104 receives the output (power) of the engine 2 through an element such as a transmission and rotates to detect the rotational speed of a drive shaft (not shown) that drives the vehicle 1.

  The air flow meter 111 detects an intake air amount that is an amount of air taken into the engine 2. The intake air temperature sensor 112 detects the intake air temperature, which is the temperature of the air taken into the engine 2. The atmospheric pressure sensor 113 detects the atmospheric pressure P [hPa]. The MAP sensor 114 is arranged on the upstream side of the intake manifold 3a of the engine 2 and detects a negative pressure that sucks intake air into the combustion chamber 2a. The water temperature sensor 115 detects the temperature of the cooling water of the engine 2. The supercharging pressure sensor 121 detects (measures) the actual actual supercharging pressure of the air supercharged by the supercharger 5.

  Various devices such as a throttle valve 34, a waste gate valve 51, an intake bypass valve 61, an injector (not shown) and a spark plug (not shown) provided in the engine 2 are connected to the output side of the ECM 10.

  The ECM 10 determines the target supercharging pressure when the supercharging pressure control start condition such as the opening degree of the throttle valve 34, that is, the throttle opening degree exceeds a predetermined opening degree, is established, and the supercharger 5 The vehicle control unit 11 functions to control the wastegate valve 51 and the throttle valve 34 so that the supercharging pressure of the supercharged air becomes the target supercharging pressure.

  At this time, the ECM 10 calculates the required torque according to the amount of depression of the accelerator pedal by the driver from the detection information detected by the crank angle sensor 102 and the vehicle speed sensor 104, and the engine 2 outputs the required torque (power). Determine the required amount of fuel injection. Further, the ECM 10 calculates the intake air amount (density) from detection information detected by the air flow meter 111, the intake air temperature sensor 112, and the atmospheric pressure sensor 113.

  The ECM 10 grasps the opening / closing timing of the intake valve and the exhaust valve from the rotation angle of the camshaft detected by the cam angle sensor 103, and obtains the intake air amount necessary for the engine 2 to output the required torque. Then, a target supercharging pressure by the supercharger 5 is set, and a control process for driving each part such as the throttle valve 34, the wastegate valve 51, the intake bypass valve 61, and the like is executed. The ECM 10 optimizes intake air intake control based on the intake negative pressure upstream of the combustion chamber 2 a detected by the MAP sensor 114 and the supercharging pressure by the supercharger 5 detected by the supercharging pressure sensor 121. It is like that.

  With this configuration, the engine 2 can cause the combustion chamber 2a to inhale an optimum amount of intake air at a boost pressure corresponding to the accelerator opening that the driver steps on, and can output high torque as the driving power of the vehicle 1. it can.

  Then, the ECM 10 performs drive control of the throttle valve 34, the wastegate valve 51, and the like based on the above various detection information so that the supercharging pressure of the intake air supercharged by the supercharger 5 matches the target supercharging pressure. It is constructed so as to function as the calculation unit 12 and the determination unit 13 when executed.

  At this time, the ECM 10 has changed the target supercharging pressure and the abnormality determination process at the time of steady state that determines whether or not the supercharging pressure of the intake air supercharged by the supercharger 5 is stable at the target supercharging pressure. In this case, a change abnormality determination process for determining whether or not an abnormality occurs is executed. In the following, the abnormality diagnosis process executed in the change abnormality determination process will be mainly described.

  The ECM 10 is used as an arithmetic unit 12 to determine whether or not an abnormality has occurred in the supercharging pressure that is adjusted toward the target supercharging pressure from various maps (not shown) that are stored (set) in advance and that are not shown. Various threshold values are calculated. The ECM 10, as the determination unit 13, compares the various threshold values calculated by the calculation unit 12 with the actual supercharging pressure in the intake pipe 3 supercharged by the supercharger 5 detected by the supercharging pressure sensor 121. Determine if it occurs. The ECM 10 constitutes an abnormality diagnosis device that performs an abnormality diagnosis that determines whether or not an abnormality has occurred by comparing various threshold values with the actual boost pressure as the calculation unit 12 and the determination unit 13, and is determined as the vehicle control unit 11. Each time the target supercharging pressure to be changed is changed, various threshold values are updated to determine whether the supercharging pressure is abnormal.

  Here, when the ECM 10 serves as the vehicle control unit 11 and the target boost pressure Ptarget is changed as the accelerator opening is changed by the driver, the actual boost pressure in the intake pipe 3 by the turbocharger 5 is changed. As shown in FIG. 3, Pr becomes substantially equal to the target supercharging pressure Ptarget and then stabilizes after it fluctuates. That is, the actual supercharging pressure Pr is a supercharging pressure before the target supercharging pressure Ptarget is changed, and is a supercharging pressure detected when the target supercharging pressure Ptarget is changed.

  At this time, if an abnormality has occurred in the turbocharger 5 or the like, the actual supercharging pressure Pr becomes an abnormal waveform that deviates significantly from the fluctuation waveform shown in FIG. 3, so the ECM 10 executes an abnormality diagnosis from the waveform. It functions as an abnormality diagnosis device.

  For example, the actual supercharging pressure Pr in the intake pipe 3 increases with a delay from the change of the target supercharging pressure Ptarget by the vehicle control unit 11 of the ECM 10, as shown in FIG. From this, the arithmetic unit 12 of the ECM 10 calculates the delay threshold Td of the time taken from the start of the change control of the target supercharging pressure Ptarget to the start of the increase of the actual supercharging pressure Pr, and the determining unit 13 As long as the actual boost pressure Pr fluctuates within a range set according to the delay threshold value Td in which the delay is allowed, it is determined that it is normal.

  The delay threshold Td is calculated from the start of the change control of the target boost pressure Ptarget based on the differential boost pressure Pd obtained by subtracting the boost pressure P1 before the change from the target boost pressure Ptarget and the engine speed. Calculated as the time it takes for Pr to start rising.

  Here, the boost pressure P1 before the change is the actual boost pressure Pr when the accelerator opening is changed or the actual boost pressure Pr when the target boost pressure Ptarget is changed. The target boost pressure Ptarget is a boost pressure value that the ECU 10 outputs as a target value in accordance with a change in the accelerator opening. The actual supercharging pressure Pr is an actual actual supercharging pressure value of the air supercharged by the supercharger 5 detected by the supercharging pressure sensor 121.

  Since the delay threshold value Td varies depending on the structure of the engine 2 and the supercharger 5, for example, a map using the differential supercharging pressure Pd and the engine speed as parameters is created in advance through experiments or calculations. Stored in the memory and obtained and set appropriately for each abnormality diagnosis.

  The allowable range that the determination unit 13 of the ECM 10 determines to be normal from the control start point at which the pre-change supercharging pressure P1 is changed to the target supercharging pressure Ptarget to the increase start point of the supercharging pressure P1 is a variation that is allowed as normal. A determination region Pt1 in which the width Pw1 is added to and subtracted from the supercharging pressure P1 before the change is set. The ECM 10 determines normal as long as the actual boost pressure Pr varies within the determination region Pt1. Note that the determination region Pt1 from the change control start point to the ascent start point is displayed as a quadrangle obtained by adding or subtracting the fluctuation range Pw1 to the boost pressure P1 before change on the graph shown in FIG.

  Further, as shown in FIG. 5, the actual supercharging pressure Pr in the intake pipe 3 starts to rise toward the target supercharging pressure Ptarget and then overshoots and reaches a maximum reached supercharging pressure (overshoot pressure). ) Reach Pover. From this, the calculation unit 12 of the ECM 10 calculates the arrival threshold value Tover of the time required from the starting point of the increase of the actual supercharging pressure Pr to the arrival point of the maximum reached supercharging pressure Pover. If the actual supercharging pressure Pr reaches the maximum attainable supercharging pressure Pover within a range set according to the attainment threshold Tover that is allowed as a time required for reaching, it is determined to be normal.

  Since the maximum reached supercharging pressure Pover and the reaching threshold value Tover differ depending on the structure of the engine 2 and the supercharger 5, the differential supercharging pressure obtained by subtracting the supercharging pressure P1 before the change from the target supercharging pressure Ptarget. A map having Pd as a parameter may be created in advance by experiment or calculation and stored in the memory, and may be obtained and set as appropriate for each abnormality diagnosis.

  The allowable range that the determination unit 13 of the ECM 10 determines to be normal is that a virtual rise line Lup is set from the rise start point of the actual boost pressure Pr to the reach point of the maximum reached boost pressure Pover, and the virtual rise line Lup is As long as the actual boost pressure Pr varies within the determination region Pt2, it is determined to be normal.

  The allowable range in the period of the arrival threshold value Tover from the starting point of the increase of the actual supercharging pressure Pr to the reaching point of the maximum supercharging pressure Pover is a determination region Pt2 that is allowed as normal centering on the virtual increase line Lup. The fluctuation range Pw2 to the outer edge is set as a range obtained by adding and subtracting, and it is determined as normal as long as the actual boost pressure Pr varies within the determination region Pt2. At this time, the determination unit 13 is normal depending on whether or not the actual boost pressure Pr is within the range obtained by adding or subtracting the fluctuation range Pw2 to the boost pressure Prup on the virtual rise line Lup during the period of the arrival threshold value Tover. Determine whether.

  Further, as shown in FIG. 6, the actual boost pressure Pr in the intake pipe 3 overshoots from the target boost pressure Ptarget and reaches the maximum reached boost pressure Pover, and then converges to the target boost pressure Ptarget. Fluctuates and stabilizes. From this, the calculation unit 12 of the ECM 10 calculates the convergence threshold Tconvergence of the time required for the actual boost pressure Pr to reach the maximum reached boost pressure Pover and stabilize at the target boost pressure Ptarget. Then, the determination unit 13 determines that the actual supercharging pressure Pr is normal within a range set according to the convergence threshold value Tconvergence allowed as the time required for the convergence. Yes.

  Since the convergence threshold value Tconvergence differs depending on the structure of the engine 2 and the supercharger 5, a map using the difference supercharging pressure Pd obtained by subtracting the supercharging pressure P1 before the change from the target supercharging pressure Ptarget as a parameter in advance. What is necessary is just to obtain and set suitably for every abnormality diagnosis, producing by experiment or calculation, storing in memory. For the convergence threshold Tconvergence, a map using the difference supercharging pressure Pd obtained by subtracting the maximum ultimate supercharging pressure Pover from the target supercharging pressure Ptarget as a parameter is created in advance and stored in the memory. You may do it.

  The allowable range that the determination unit 13 of the ECM 10 determines to be normal is the fluctuation range Pw3 that is normally allowed for the target boost pressure Ptarget from the time when the maximum reached boost pressure Pover is reached to the final determination switching point in the period of the convergence threshold Tconvergence. A determination region Pt3 obtained by adding and subtracting is set. The determination unit 13 determines normal as long as the actual boost pressure Pr varies within the determination region Pt3.

  When the ECM 10 changes the actual supercharging pressure Pr from the pre-change supercharging pressure P1 to the target supercharging pressure Ptarget, as shown in FIG. 7, the arithmetic unit 12 performs the above-described delay threshold value Td and arrival threshold value Tover. The normal determination areas Pt1 to Pt3 are calculated and set together with the convergence threshold Tconvergence. The ECM 10 determines, as the determination unit 13, whether or not the actual supercharging pressure Pr fluctuates within the normal determination regions Pt1 to Pt3 during various threshold values Td, Tover, and Tconvergence. When it is diagnosed that an abnormality has occurred in the pressure, the supercharging control is immediately stopped to prevent the occurrence of a malfunction.

  Here, the ECM 10 not only increases the supercharging pressure, but also controls the supercharger 5 to decrease the supercharging pressure P1 to the supercharging pressure P2 (P1> P2) as shown in FIG. There is also. Also in this case, as shown in FIG. 9, the ECM 10 calculates and sets the normal determination regions Pt <b> 1 to Pt <b> 3 together with the delay threshold value Td, the arrival threshold value Tover, and the convergence threshold value Tconvergence as the calculation unit 12. Further, the ECM 10 determines, as the determination unit 13, whether or not the actual supercharging pressure Pr varies within the normal determination regions Pt <b> 1 to Pt <b> 3 during the various threshold values Td, Tover, and Tconvergence. When it is diagnosed that an abnormality has occurred in the supply pressure, the supercharging control is immediately started to prevent a problem from occurring. At this time, the actual supercharging pressure Pr drops to a point where the minimum ultimate supercharging pressure (undershoot pressure) Pover that deviates maximum from the starting point of lowering. From this, the ECM 10 sets a virtual descending line Ldown from the descending start point to the minimum reaching point, and sets the normal determination region Pt2.

  Specifically, when the ECM 10 starts / continues driving control of the supercharger 5 according to the accelerator pedal depression amount (accelerator opening) by the driver detected by the accelerator sensor 101, as shown in the flowchart of FIG. In addition, setting processing such as various threshold values and areas necessary for the abnormality diagnosis processing is executed.

  As shown in FIG. 10, first, the ECM 10 includes a crank angle sensor 102, a cam angle sensor 103, a vehicle speed sensor 104, an air flow meter 111, an intake air temperature sensor 112, an atmospheric pressure sensor 113, a MAP sensor 114, a water temperature sensor 115, a supercharger. Various sensor values (detection information) detected by the pressure sensor 121 and the like are acquired (step S11).

  Next, the ECM 10 confirms whether or not the conditions for executing the abnormality diagnosis process are met (step S12). If not, the ECM 10 is temporarily terminated and the supercharging pressure control by the next supercharger 5 is performed. At the time of processing, the process restarts from step S11. Here, the abnormality diagnosis processing condition is a condition for starting the abnormality diagnosis processing. For example, when the target boost pressure exceeds a preset pressure value, or the difference between the target boost pressure Ptarget before and after the change is determined in advance. Exceeding the set pressure value is a condition for starting the abnormality diagnosis process. If the water temperature detected by the water temperature sensor 115 is equal to or lower than a predetermined value, the abnormality diagnosis may not be performed because the engine 2 is not in a warm-up state.

  In step S12, the ECM 10 that has confirmed that the conditions for executing the abnormality diagnosis process are met, sets the delay threshold (time) Td required from the start of the change control of the target boost pressure Ptarget to the start of the increase of the actual boost pressure Pr. Determine (calculate).

  Next, the ECM 10 determines the maximum reached supercharging pressure Pover that is reached after overshooting after the actual supercharging pressure Pr starts to increase toward the target supercharging pressure Ptarget (step S14). Next, the ECM 10 determines an arrival threshold value (time) Tover required from the starting point of the increase of the actual supercharging pressure Pr to the reaching point of the maximum ultimate supercharging pressure Pover (step S15). Next, the ECM 10 determines a convergence threshold (time) Tconvergence required to converge to the target boost pressure Ptarget and stabilize after reaching the maximum reached boost pressure Pover (step S16).

  Next, the ECM 10 sets the actual boost pressure Pr from the control start point at which the pre-change boost pressure P1 is changed to the target boost pressure Ptarget to the start point of increase of the actual boost pressure Pr (supercharge pressure P1). From the rising start point to the reaching point of the maximum reached supercharging pressure Pover (virtual rising line Lup) and from the reaching point of the maximum reaching supercharging pressure Pover to the determination switching point at the end of the convergence threshold Tconvergence (target supercharging pressure Ptarget) A time transition line of the pressure changing between each point is determined (step S17), and normal only within the range of the fluctuation range Pw1 to Pw3 centering on the time transition line of the pressure change of the supercharging pressure. Normality determination areas Pt1 to Pt3 to be determined are determined (step S18). The temporal transition line may be obtained not only by a straight line connecting each point including the virtual rising line Lup but also by an approximate calculation process such as linear, polynomial, or power. Further, the normal determination area may be set so that the temporal transition line has a certain width.

  Thereafter, as shown in the flowchart of FIG. 11, the ECM 10 performs a determination process in the abnormality diagnosis process, and functions as an abnormality diagnosis device that determines whether there is an abnormality in the supercharging pressure by the supercharger 5. ing. Here, after the actual supercharging pressure Pr has shifted to the determination switching point at the end of the convergence threshold Tconvergence, the ECM 10 switches to the execution of the steady-state abnormality determination process, and supercharges the intake air supercharged by the supercharger 5. It is determined whether or not the supply pressure is stable at the target boost pressure.

  First, the ECM 10 confirms whether or not the actual supercharging pressure Pr varies within the normal determination regions Pt1 to Pt3 corresponding to the time transition from the supercharging pressure change control start time (step S21). If it is within the range, normal determination is made (step S22), the process returns to step S11 as it is, and the abnormality diagnosis process is repeated in parallel with the supercharging pressure change control process.

  In step S21, the ECM 10 that has confirmed that the actual boost pressure Pr is outside the range of the normal determination regions Pt1 to Pt3 resets the provided timer function (step S23), and then starts the timer function (step S24). ), And measure the elapsed time since the confirmation.

  Next, the ECM 10 counts a determination time that is set in advance by confirming that the actual supercharging pressure Pr has deviated from the normal determination region Pt1 to Pt3 out of the normal determination region Pt1 to Pt3. It is confirmed whether or not it has elapsed (step S25). If it has not elapsed, the process returns to step S21 and the same processing is repeated.

  After returning from step S25 to step S21 and before confirming that the set determination time has elapsed in step S25 again, in step S21, the actual boost pressure Pr is within the range of normal determination regions Pt1 to Pt3. If it is determined as normal, the ECM 10 proceeds directly to step S22 and continues the abnormality diagnosis process in parallel with the supercharging pressure change control process.

  In addition, in step S25, when it is confirmed that the setting determination time has passed while the actual supercharging pressure Pr remains outside the range of the normal determination regions Pt1 to Pt3, the ECM 10 makes an abnormality determination (step S26). ) Immediately terminate the supercharging control, for example, execute a process for notifying the driver of the abnormality, and perform a supercharging pressure abnormality prevention measure such as causing the wastegate valve 51 to function (step S26). The abnormality diagnosis process is terminated.

  Therefore, an abnormality diagnosis can be made based on whether or not the actual boost pressure Pr is within the normal determination range Pt1 to Pt3 without waiting for the actual boost pressure Pr to converge to the target boost pressure Ptarget and stabilize. When an abnormality occurs, it is possible to grasp the occurrence of the abnormality at an early stage and quickly take action.

  As described above, in the ECM 10 of the present embodiment, the actual boost pressure Pr in the intake pipe 3 that rises toward the target boost pressure Ptarget has various threshold values Td, Tover, and Tconvergence from the start of the boost pressure change control. Whether or not the supercharger 5 is functioning normally is determined based on whether or not it varies within the normal determination regions Pt1 to Pt3 corresponding to the period, and abnormality diagnosis is performed.

  Therefore, an abnormality diagnosis can be made following the fluctuation of the actual supercharging pressure Pr, and an abnormality is diagnosed and treated immediately, and a malfunction occurs due to an overboost or underboost of the supercharging pressure. Can be prevented in advance.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 Vehicle 2 Engine (Internal combustion engine)
3 Intake pipe (intake passage)
4 Exhaust pipe 5 Supercharger 7 EGR pipe 11 Vehicle control section 12 Calculation section 13 Determination section 32 Compressor 33 Intercooler 34 Throttle valve 42 Exhaust turbine 50 Exhaust bypass 51 Wastegate valve 60 Intake bypass 61 Intake bypass valve 71 EGR valve 101 Accelerator Sensor 102 Crank angle sensor 103 Cam angle sensor 104 Vehicle speed sensor 115 Water temperature sensor 121 Supercharging pressure sensor (supercharging pressure measuring unit)

Claims (8)

An abnormality diagnosis device for an internal combustion engine equipped with a supercharger,
A supercharging pressure measuring unit that measures an actual supercharging pressure at a predetermined position on the intake passage of the internal combustion engine;
A vehicle control unit for determining a target boost pressure to be changed according to the output of the internal combustion engine;
A calculation unit that calculates a threshold value used for abnormality determination of a supercharging pressure that changes toward the target supercharging pressure based on a preset map;
A determination unit that performs an abnormality determination of the supercharging pressure based on the threshold value calculated by the arithmetic unit and the actual supercharging pressure measured by the supercharging pressure measurement unit,
Along with a change in the target boost pressure determined by the vehicle control unit, the calculation unit calculates a threshold value used for determining an abnormality in the boost pressure that changes toward the target boost pressure, and the determination unit is calculated. An abnormality diagnosis device for an internal combustion engine that performs abnormality diagnosis of the internal combustion engine by determining abnormality of a supercharging pressure by the supercharger based on the threshold value.   The calculation unit uses the map set in advance to determine a delay from a change in the target boost pressure determined by the vehicle control unit to an increase in the actual boost pressure on the intake passage, and the actual excess pressure. An overshoot pressure or an undershoot pressure at which the supply pressure and the target supercharging pressure deviate to a maximum, an arrival time required until the actual supercharging pressure and the target supercharging pressure deviate to a maximum, and the actual overpressure The threshold value used for determining an abnormality of the boost pressure that changes toward the target boost pressure is calculated based on at least one of a convergence time until the boost pressure is stabilized at the target boost pressure. The abnormality diagnosis apparatus for an internal combustion engine according to claim 1.   The abnormality diagnosis device for an internal combustion engine according to claim 2, wherein the delay is determined based on a rotational speed of the internal combustion engine and a change amount of the target supercharging pressure.   The abnormality diagnosis device for an internal combustion engine according to claim 2, wherein the overshoot pressure or undershoot pressure is determined based on a pre-change supercharging pressure and a target supercharging pressure.   The abnormality diagnosis device for an internal combustion engine according to claim 2, wherein the arrival time is determined based on a pre-change supercharging pressure and a target supercharging pressure.   The abnormality diagnosis device for an internal combustion engine according to claim 2, wherein the convergence time is determined based on a pre-change supercharging pressure and a target supercharging pressure.   The abnormality diagnosis device for an internal combustion engine according to claim 2, wherein the convergence time is determined based on the overshoot pressure or the undershoot pressure.   2. The abnormality diagnosis device for an internal combustion engine according to claim 1, wherein the determination unit performs the abnormality determination only when the range based on the threshold calculated by the calculation unit deviates for a predetermined time or more.

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