JP2014092066A - EGR valve fault detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the opening and fixing of an EGR valve in a hybrid vehicle equipped with a plurality of driving sources including an internal combustion engine comprising an EGR device.SOLUTION: An ECU (EGR valve fault detection device) 100 is configured to determine a state of an EGR valve 72 on the basis of a change in intake manifold pressure when the EGR valve 72 is set to be opened by a stepping motor 73 in a charge control-performed state, in the case where a combustion state of an engine 1 is unstable in an operation region in which exhaust gas is not returned to an intake manifold 11b.

Description

  The present invention relates to an EGR valve failure detection apparatus in a hybrid vehicle equipped with a plurality of drive sources including an internal combustion engine (hereinafter also referred to as an engine).

  Conventionally, an internal combustion engine (an internal combustion engine with an EGR device) including an EGR (Exhaust Gas Recirculation) device has been known. The EGR device includes an EGR passage that recirculates a part of the exhaust gas discharged to the exhaust passage to the intake passage, an EGR valve provided in the EGR passage, and the like.

  In such an internal combustion engine with an EGR device, when the EGR valve is fixed (open fixed) in the open state, the operating state of the internal combustion engine becomes unstable and misfires are likely to occur. Therefore, conventionally, in an idling state of the internal combustion engine, there is a method of forcibly opening and closing the EGR valve while monitoring the intake pressure in the intake manifold, and detecting sticking of the EGR valve based on a change in the intake pressure at that time. Are known.

  On the other hand, as an example of a hybrid vehicle, an internal combustion engine with an EGR device, a first electric motor that mainly functions as a generator, and a planetary gear that transmits the power of the internal combustion engine by dividing it into drive wheels (drive shafts) and the first electric motor There is a hybrid vehicle including a mechanism and a second electric motor that mainly functions as an electric motor and can input and output power to a drive shaft. In such a hybrid vehicle, electric power can be generated by rotating the first electric motor with the power of the internal combustion engine, and the second electric motor can be driven by the electric power, or the electric power can be charged in the power storage device. .

  In such a hybrid vehicle, when the remaining amount of the power storage device is small, power is generated by the first motor by the power of the internal combustion engine, and the power is charged in the power storage device. At this time, since the intake pressure also fluctuates due to fluctuations in the load of the internal combustion engine, it has been difficult for the conventional hybrid vehicle to properly implement the above-described method for detecting the sticking of the EGR valve.

  Therefore, the EGR valve is forcibly opened and closed while the first electric motor is driven and charged by the internal combustion engine so that the load of the internal combustion engine is constant, and the EGR valve is fixed based on the change in the intake pressure at that time. Has been proposed (see, for example, Patent Document 1).

JP 2010-196684 A

  However, in the prior art as described in Patent Document 1, it is possible to detect the EGR valve sticking, but whether the EGR valve is stuck in a closed state (closed sticking) or the EGR valve is stuck open. It is not possible to determine whether or not

  The present invention has been made in consideration of such a situation, and in a hybrid vehicle equipped with a plurality of drive sources including an internal combustion engine equipped with an EGR device, it is possible to determine whether the EGR valve is stuck open. The purpose is to realize a valve failure detection device.

  An EGR valve failure detection device according to the present invention includes an EGR passage that recirculates part of exhaust gas discharged to an exhaust passage to an intake passage, an EGR valve provided in the EGR passage, and a drive unit for opening and closing the EGR valve. And applied to a hybrid vehicle equipped with a plurality of drive sources including an internal combustion engine equipped with an EGR device. Then, the EGR valve failure detection device is configured so that the EGR valve is opened by the drive unit in a state where charge control is performed when the combustion state of the internal combustion engine is unstable in the operation region where the exhaust gas is not recirculated to the intake passage. The state of the EGR valve is determined based on the change in the intake manifold pressure when the operation is performed.

  As described above, when the combustion state of the internal combustion engine is unstable in the operation region where the exhaust gas is not recirculated to the intake passage, there is a possibility that the EGR valve is in the open state. There is a possibility of open adhesion. Thereby, in this case, it is determined whether or not the EGR valve is fixed based on the change in the intake manifold pressure. When the EGR valve is fixed, it is determined that the EGR valve is open and fixed. it can. Further, by determining the state of the EGR valve in a state where the charge control is performed, it is possible to suppress fluctuations in the load of the internal combustion engine, so that the state (adhesion) of the EGR valve is based on the change in the intake manifold pressure. Can be determined appropriately.

  In the EGR valve failure detection device, when the combustion state of the internal combustion engine is not unstable in the operation region where the exhaust gas is not recirculated to the intake passage, the change in the intake manifold pressure when the EGR valve is opened by the drive unit. It may be configured to determine the state of the EGR valve based on it.

  As described above, when the combustion state of the internal combustion engine is not unstable in the operation region where the exhaust gas is not recirculated to the intake passage, it is considered that the EGR valve is in the closed state, and therefore the EGR valve is not closed but closed. There may be sticking. Thereby, in this case, it is determined whether or not the EGR valve is fixed based on the change in the intake manifold pressure. When the EGR valve is fixed, it is determined that the EGR valve is closed and fixed. it can.

  In the EGR valve failure detection device, the hybrid vehicle includes an internal combustion engine, a first electric motor capable of inputting / outputting power, an output shaft of the internal combustion engine, a rotation shaft of the first electric motor, and a drive shaft connected to drive wheels. A planetary gear mechanism in which three rotating elements are connected to the three shafts, a second motor capable of inputting / outputting power to / from the drive shaft, and a power storage device capable of exchanging power with the first motor and the second motor. In the charging control, the electric power generated by the first electric motor rotated by the power of the internal combustion engine may be charged in the power storage device.

  According to the EGR valve failure detection device of the present invention, it is possible to determine whether the EGR valve is stuck open in a hybrid vehicle equipped with a plurality of drive sources including an internal combustion engine equipped with an EGR device.

It is a schematic structure figure showing an example of a hybrid vehicle to which the present invention is applied. It is a schematic block diagram of the engine (internal combustion engine) mounted in the hybrid vehicle of FIG. It is a block diagram which shows the control system of the hybrid vehicle of FIG. It is a timing chart which shows an example in case an EGR valve is not a fixed state in secondary determination. It is a flowchart which shows an example of a failure detection of an EGR valve.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where the present invention is applied to an FF (front engine / front drive) type hybrid vehicle will be described.

  FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle to which the present invention is applied. As shown in FIG. 1, a hybrid vehicle HV includes an engine (internal combustion engine) 1 that generates driving force for vehicle travel, a first motor generator MG1 (first electric motor) that mainly functions as a generator, and an electric motor mainly. A second motor generator MG2 (second electric motor), a power split mechanism 3, a reduction mechanism 4, a counter drive gear 51, a counter driven gear 52, a final gear 53, a differential gear 54, drive shafts (drive shafts) 61, 61, The left and right drive wheels (front wheels) 6L and 6R and an ECU (Electronic Control Unit) 100 are provided, and the EGR valve failure detection device of the present invention is realized by a program executed by the ECU 100.

  The ECU 100 includes, for example, an HV (hybrid) ECU, an engine ECU, a battery ECU, and the like, and these ECUs are connected so as to communicate with each other.

  Next, components such as the engine 1, the motor generators MG1 and MG2, the power split mechanism 3, the reduction mechanism 4, and the ECU 100 will be described.

-Engine-
A schematic configuration of the engine 1 will be described with reference to FIG. FIG. 2 shows only the configuration of one cylinder of the engine 1.

  The engine 1 in this example is a port injection type four-cylinder gasoline engine mounted on a vehicle, and a piston 1c that reciprocates in the vertical direction is provided in a cylinder block 1a constituting each cylinder. The piston 1c is connected to the crankshaft 1e via a connecting rod 1f, and the reciprocating motion of the piston 1c is converted into rotation of the crankshaft 1e by the connecting rod 1f.

  A signal rotor 1g is attached to the crankshaft 1e. A crank position sensor 102 for detecting a crank angle is disposed in the vicinity of the side of the signal rotor 1g. The crank position sensor 102 is, for example, an electromagnetic pickup, and generates a pulsed signal (voltage pulse) corresponding to the teeth of the signal rotor 1g when the crankshaft 1e rotates. The engine speed can be calculated from the output signal of the crank position sensor 102.

  A water temperature sensor 104 that detects the water temperature of the engine cooling water is disposed in the cylinder block 1 a of the engine 1. A cylinder head 1b is provided at the upper end of the cylinder block 1a, and a combustion chamber 1d is formed between the cylinder head 1b and the piston 1c. A spark plug 16 is disposed in the combustion chamber 1 d of the engine 1. The ignition timing of the spark plug 16 is adjusted by the igniter 16a. The igniter 16a is controlled by the ECU 100.

  An intake passage 11 and an exhaust passage 12 are connected to the combustion chamber 1 d of the engine 1. A part of the intake passage 11 is formed by an intake port 11a and an intake manifold 11b. A surge tank 11 c is provided in the intake passage 11. The intake manifold 11b is provided with an intake manifold pressure sensor 111 for detecting the pressure (intake manifold pressure) of the intake manifold 11b. A part of the exhaust passage 12 is formed by an exhaust port 12a and an exhaust manifold 12b.

  In the intake passage 11 of the engine 1, an air cleaner 18 that filters intake air, a hot-wire air flow meter 105, an intake air temperature sensor 106 (built in the air flow meter 105), a throttle valve 17 for adjusting the intake air amount of the engine 1, and the like. Is arranged.

  The throttle valve 17 is provided on the upstream side of the surge tank 11c (upstream side of the intake flow) and is driven by the throttle motor 17a. The opening degree of the throttle valve 17 is detected by a throttle opening degree sensor 103. The throttle opening of the throttle valve 17 is driven and controlled by the ECU 100.

  For the control of the throttle valve 17, for example, an optimal intake air amount (target intake air amount) corresponding to the state of the engine 1 such as the engine speed and the accelerator pedal depression amount (accelerator opening) of the driver is obtained. Electronic throttle control is used to control the throttle opening. In such electronic throttle control, the throttle opening sensor 103 is used to detect the actual throttle opening of the throttle valve 17, and the actual throttle opening is the throttle opening (target throttle opening at which the target intake air amount is obtained). ), The throttle motor 17a of the throttle valve 17 is feedback-controlled.

  An intake valve 13 is provided between the intake passage 11 of the engine 1 and the combustion chamber 1d. By opening and closing the intake valve 13, the intake passage 11 and the combustion chamber 1d are communicated or blocked. Further, an exhaust valve 14 is provided between the exhaust passage 12 and the combustion chamber 1d. By opening and closing the exhaust valve 14, the exhaust passage 12 and the combustion chamber 1d are communicated or blocked.

  The opening / closing drive of the intake valve 13 and the exhaust valve 14 is performed by each rotation of the intake camshaft 13a and the exhaust camshaft 14a to which the rotation of the crankshaft 1e is transmitted through a timing chain or the like. In the vicinity of the intake camshaft 13a, a cam position sensor 109 is provided that generates a pulse signal when the piston 1c of a specific cylinder (for example, the first cylinder) reaches the compression top dead center (TDC). .

  An injector (fuel injection valve) 15 capable of injecting fuel is disposed in the intake port 11 a of the intake passage 11. The injector 15 is provided for each cylinder. Each injector 15 is supplied with fuel stored in a fuel tank (not shown) of a fuel supply system, and fuel is injected from the injector 15 into the intake port 11a. This injected fuel is mixed with intake air to form an air-fuel mixture and introduced into the combustion chamber 1 d of the engine 1. The air-fuel mixture (fuel + air) introduced into the combustion chamber 1d is ignited by the spark plug 16 and combusted and exploded. The piston 1c is reciprocated by the high-temperature and high-pressure combustion gas generated at this time, the crankshaft 1e is rotated, and the driving force (output torque) of the engine 1 is obtained. The combustion gas is discharged into the exhaust passage 12 when the exhaust valve 14 is opened.

A three-way catalyst 19 is disposed in the exhaust passage 12. In the three-way catalyst 19, oxidation of CO and HC and reduction of NOx in the exhaust gas exhausted from the combustion chamber 1d to the exhaust passage 12 is performed to make them harmless CO ₂ , H ₂ O, and N ₂ . In this way, the exhaust gas is purified.

An air-fuel ratio sensor (A / F sensor) 107 is disposed in the exhaust passage 12 upstream of the three-way catalyst 19 (upstream of the exhaust flow). The air-fuel ratio sensor 107 is a sensor that exhibits linear characteristics with respect to the air-fuel ratio. An O ₂ sensor 108 is disposed in the exhaust passage 12 on the downstream side of the three-way catalyst 19. The O ₂ sensor 108 generates an electromotive force according to the oxygen concentration in the exhaust gas. When the output is higher than the voltage (comparison voltage) corresponding to the theoretical air-fuel ratio, the O ₂ sensor 108 determines that the output is rich, and conversely compares When the output is lower than the voltage, it is judged as lean. The output signals of the air-fuel ratio sensor 107 and the O ₂ sensor 108 are used for air-fuel ratio feedback control (for example, refer to the technique described in Japanese Patent Laid-Open No. 2010-007561).

  And the output of the engine 1 of the above structure is transmitted to the input shaft 21 via the crankshaft (output shaft) 1e and the damper 2 (refer FIG. 1). The damper 2 is a coil spring type transaxle damper, for example, and absorbs torque fluctuations of the engine 1.

(EGR device)
As shown in FIG. 2, the engine 1 is equipped with an EGR device 7. The EGR device 7 recirculates a part of the exhaust gas (EGR gas) flowing through the exhaust passage 12 to the intake passage 11 and supplies the exhaust gas again to the combustion chamber 1d of each cylinder, whereby the combustion speed and combustion temperature in the combustion chamber 1d are obtained. Is a device that reduces the amount of NOx generated.

  The EGR device 7 includes an EGR passage 71 that connects the intake passage 11 (intake manifold 11b) and the exhaust passage 12, an EGR valve 72 that is provided in the EGR passage 71, and the like. The EGR valve 72 is driven to open and close by a stepping motor 73. Further, the EGR device 7 is not provided with an opening degree sensor, and the opening degree (%) is determined based on, for example, the number of steps of the stepping motor 73.

  In the EGR device 7 having such a configuration, the EGR amount (exhaust recirculation amount) introduced from the exhaust passage 12 into the intake passage 11 (combustion chamber 1d) of each cylinder by controlling the opening degree of the EGR valve 72. The EGR rate [EGR amount / (EGR amount + intake air amount (new air amount)) (%)] can be adjusted. Such control of the EGR device 7 (control of the stepping motor 73) is executed by the ECU 100.

  The EGR device 7 may be provided with an EGR cooler for cooling the EGR gas that passes (refluxs) through the EGR passage 71.

-Motor generator-
As shown in FIG. 1, the first motor generator MG1 includes a rotor MG1R made of a permanent magnet supported so as to be relatively rotatable with respect to the input shaft 21, and a stator MG1S around which a three-phase winding is wound. The AC synchronous generator functions as a generator and also functions as an electric motor (electric motor). Similarly, the second motor generator MG2 includes an AC synchronous generator including a rotor MG2R made of a permanent magnet supported so as to be relatively rotatable with respect to the input shaft 21, and a stator MG2S wound with a three-phase winding. It functions as an electric motor (electric motor) as well as a generator.

  As shown in FIG. 3, first motor generator MG <b> 1 and second motor generator MG <b> 2 are each connected to battery (power storage device) 300 via inverter 200. Inverter 200 is controlled by ECU 100, and regeneration or power running (assist) of each motor generator MG 1, MG 2 is set by the control of inverter 200. The regenerative power at that time is charged into the battery 300 via the inverter 200. In addition, driving power for each of the motor generators MG1 and MG2 is supplied from the battery 300 via the inverter 200.

-Power split mechanism-
As shown in FIG. 1, the power split mechanism 3 includes an external gear sun gear S3 that rotates at the center of a plurality of gear elements, and an external gear pinion gear P3 that revolves around the sun gear S3 while rotating around its periphery. And a planetary gear mechanism that has a ring gear R3 of an internal gear formed in a hollow ring so as to mesh with the pinion gear P3, and a planetary carrier CA3 that supports the pinion gear P3 and rotates through the revolution of the pinion gear P3. Yes.

  The planetary carrier CA3 is connected to the input shaft 21 on the engine 1 side so as to rotate together. The sun gear S3 is connected to the rotor MG1R of the first motor generator MG1 so as to rotate together. The ring gear R3 is connected to the drive shafts 61 and 61 (drive wheels 6L and 6R) via the counter drive gear 51, the counter driven gear 52, the final gear 53, and the differential device 54. Thereby, the sun gear S3, the ring gear R3, and the planetary carrier CA3 constitute the “three rotating elements of the planetary gear mechanism” in the present invention.

  In the power split mechanism 3 having such a configuration, when the reaction torque of the first motor generator MG1 is input to the sun gear S3 with respect to the output torque of the engine 1 input to the planetary carrier CA3, the output element A torque larger than the torque input from the engine 1 appears in a certain ring gear R3. In this case, the first motor generator MG1 functions as a generator. When first motor generator MG1 functions as a generator, the driving force of engine 1 input from planetary carrier CA3 is distributed according to the gear ratio between sun gear S3 and ring gear R3.

  On the other hand, when the engine 1 is requested to start, the first motor generator MG1 functions as an electric motor (starter motor), and the driving force of the first motor generator MG1 is applied to the crankshaft 1e via the sun gear S3 and the planetary carrier CA3. Given, the engine 1 is cranked.

  Further, while the vehicle is traveling, the power split mechanism 3 changes the rotational speed of the first motor generator MG1 up and down when the rotational speed of the ring gear R3 (output shaft rotational speed) is constant. The rotational speed of the engine 1 can be changed continuously (in a stepless manner). That is, the power split mechanism 3 functions as a transmission unit.

-Reduction mechanism-
The reduction mechanism 4 is rotatably supported by a sun gear S4, which is an external gear that rotates at the center of a plurality of gear elements, and a carrier (transaxle case) CA4, and an external gear pinion gear P4 that rotates while circumscribing the sun gear S4. And a planetary gear mechanism having a ring gear R4 of an internal gear formed in a hollow annular shape so as to mesh with the pinion gear P4. The ring gear R4 of the reduction mechanism 4, the ring gear R3 of the power split mechanism 3, and the counter drive gear 51 are integrated with each other. Sun gear S4 is connected to rotor MG2R of second motor generator MG2 so as to rotate together.

  The reduction mechanism 4 decelerates the driving force of the second motor generator MG2 at an appropriate reduction ratio. The reduced driving force is transmitted to the left and right drive wheels 6L and 6R via the counter drive gear 51, the counter driven gear 52, the final gear 53, the differential device 54, and the drive shafts 61 and 61.

-Shift operation device-
A shift operation device 8 (see FIG. 3) is disposed in the vicinity of the driver's seat in the hybrid vehicle HV. The shift operating device 8 is provided with a shift lever 81 that can be displaced. The shift operating device 8 of this example includes a drive range (D range) for forward travel, a brake range (B range) for forward travel with a large braking force (engine brake) when the accelerator is off, and a reverse travel range. A reverse range (R range) and a neutral range (N range) are set, and the driver can displace the shift lever 81 to a desired range. These positions of the D range, B range, R range, and N range are detected by the shift position sensor 110. An output signal of the shift position sensor 110 is input to the ECU 100. Note that the parking position (P position) can be set by a separately arranged P switch.

-ECU-
The ECU 100 is an electronic control device that performs various controls including operation control of the engine 1 and cooperative control of the engine 1 and the motor generators MG1 and MG2, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM. (Random Access Memory) and a backup RAM. The ECU 100 is configured to detect a failure of the EGR valve 72, which will be described in detail later.

  The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory that temporarily stores calculation results from the CPU, data input from each sensor, and the like, and the backup RAM is a nonvolatile memory that stores data to be saved when an ignition switch (not shown) is turned off. Memory.

As shown in FIG. 3, the ECU 100 includes an accelerator opening sensor 101 that detects an accelerator opening Acc that is an accelerator pedal depression amount, and a crank position sensor that transmits a pulse signal each time the crankshaft 1e rotates by a predetermined angle. 102, a throttle opening sensor 103 for detecting the opening of the throttle valve 17, a water temperature sensor 104 for detecting the engine cooling water temperature, an air flow meter 105 for detecting the intake air amount, an intake air temperature sensor 106 for detecting the intake air temperature, an air-fuel ratio. A sensor 107, an O ₂ sensor 108, a cam position sensor 109, a shift position sensor 110, an intake manifold pressure sensor 111 for detecting intake manifold pressure, and the like are connected, and signals from these sensors are input to the ECU 100. It has become so. Although not shown, a current sensor for detecting the charge / discharge current of the battery 300, a battery temperature sensor, and the like are also connected, and signals from these sensors are also input to the ECU 100.

  The ECU 100 is connected to an injector 15, an igniter 16 a that adjusts the ignition timing of the spark plug 16, a throttle motor 17 a that drives the throttle valve 17 of the engine 1 to open and close, a stepping motor 73 that opens and closes the EGR valve 72, and the like. .

  The ECU 100 executes various controls of the engine 1 such as throttle opening control (intake air amount control), fuel injection amount control, and ignition timing control of the engine 1 based on the output signals of the various sensors described above. In addition, the entire hybrid system is controlled (torque control of each motor generator MG1, MG2, etc.).

  In addition, the ECU 100 calculates a target EGR rate based on the current engine speed and the engine load using an EGR map that defines the relationship between the engine speed and the engine load and the target EGR rate. Then, the target EGR opening of the EGR valve 72 and the target throttle opening of the throttle valve 17 are calculated so that the current EGR rate becomes the target EGR rate, and the target EGR opening and the target throttle valve opening are calculated. Based on this, the EGR valve 72 and the throttle valve 17 are controlled to open and close.

  The EGR map is created in advance by experiments, simulations, and the like, and is stored in the ROM of the ECU 100. The engine speed used for calculating the target EGR rate can be obtained from the output signal of the crank position sensor 102. The engine load can be calculated with reference to a map or the like from the accelerator opening obtained from the output signal of the accelerator opening sensor 101 and the engine speed.

  Further, in order to manage the battery 300, the ECU 100 manages the battery 300 based on the charge / discharge current integrated value detected by the current sensor, the battery temperature detected by the battery temperature sensor, and the like. SOC: State of Charge), input limit Win and output limit Wout of the battery 300, and the like are calculated.

  In addition, an inverter 200 is connected to the ECU 100. Inverter 200 includes an IPM (Intelligent Power Module) for controlling motor generators MG1 and MG2. Each IPM is constituted by a plurality of (for example, six) semiconductor switching elements (for example, an IGBT (Insulated Gate Bipolar Transistor)).

  For example, inverter 200 converts DC current from battery 300 into motor generators MG1 and MG2 in accordance with a command signal from ECU 100 (for example, torque command value of first motor generator MG1, torque command value of second motor generator MG2). In order to charge the battery 300 with the AC current generated by the first motor generator MG1 by the power of the engine 1 and the AC current generated by the second motor generator MG2 by the regenerative brake. Convert to DC current. Inverter 200 supplies the alternating current generated by first motor generator MG1 as drive power for second motor generator MG2 in accordance with the traveling state.

-Control of hybrid system-
The hybrid vehicle HV configured as described above calculates the torque (required torque) to be output to the drive wheels 6L and 6R based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal by the driver. The engine 1 and the motor generators MG1, MG2 are controlled to run with the required driving force corresponding to the required torque.

  As operation control of the engine 1 and the motor generators MG1 and MG2, specifically, in order to reduce fuel consumption, the second motor generator MG2 is used in an operation region where the required torque is relatively low. The required torque is obtained. On the other hand, in the operation region where the required torque is relatively high, the second motor generator MG2 is used and the engine 1 is driven so that the required torque can be obtained by the driving force from these driving sources.

  More specifically, when the vehicle 1 starts or runs at a low speed and the operation efficiency of the engine 1 is low, the vehicle travels (EV travel) only by the second motor generator MG2. Further, EV driving is also performed when the driver selects the EV driving mode with a driving mode selection switch arranged in the vehicle interior.

  On the other hand, during normal traveling (HV traveling or engine traveling), for example, the driving force of the engine 1 is divided into two paths by the power split mechanism 3, and the driving wheels 6L and 6R are directly driven (driven by direct torque) with the one driving force. And the first motor generator MG1 is driven with the other driving force to generate electric power. At this time, the second motor generator MG2 is driven with electric power generated by driving the first motor generator MG1 to assist driving of the driving wheels 6L and 6R (driving by an electric path).

  Thus, the power split mechanism 3 functions as a differential mechanism, and the main part of the power from the engine 1 is mechanically transmitted to the drive wheels 6L and 6R by the differential action, and the remaining part of the power from the engine 1 is transmitted. Is electrically transmitted by using an electric path from the first motor generator MG1 to the second motor generator MG2, thereby functioning as an electric continuously variable transmission in which the gear ratio is electrically changed. This makes it possible to freely operate the engine rotation speed and the engine torque without depending on the rotation speed (rotation speed) and torque of the drive wheels 6L and 6R, and the driving force required for the drive wheels 6L and 6R. It is possible to obtain the operating state of the engine 1 with the optimized fuel consumption rate.

  Further, during high speed traveling, the electric power from the battery 300 is further supplied to the second motor generator MG2, and the output of the second motor generator MG2 is increased to add driving force to the driving wheels 6L and 6R (driving force assist). Power running).

  Further, at the time of deceleration, the second motor generator MG2 functions as a generator to perform regenerative power generation, and the recovered power is stored in the battery 300. When the amount of charge of the battery 300 (the remaining capacity; SOC) decreases and charging is particularly necessary, the output of the engine 1 is increased and the amount of power generated by the first motor generator MG1 is increased to charge the battery 300. Increase the amount. Further, there is a case where control is performed to increase the output of the engine 1 as necessary even during low-speed traveling. For example, it is necessary to charge the battery 300 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 1 to a predetermined temperature.

  Further, in the hybrid vehicle HV of the present embodiment, the engine 1 is stopped in order to improve fuel efficiency depending on the driving state of the vehicle and the state of the battery 300. And after that, the driving | running state of the hybrid vehicle HV and the state of the battery 300 are detected, and the engine 1 is restarted. Thus, in the hybrid vehicle HV, the engine 1 is intermittently operated (operation that repeats engine stop and restart).

  Here, when the engine 1 that is intermittently operated is changed from the operating state to the stopped state, for example, the rotation of the engine 1 is stopped if the vehicle speed is low, and the engine 1 is restarted if the vehicle speed is high. In addition, when the engine 1 is motored by the first motor generator MG1, the rotational speed of the engine 1 is maintained so as not to fall below a predetermined value. That is, when the fuel cut to stop the fuel injection from the injector 15 is performed, the rotation of the engine 1 is stopped, and the engine 1 is driven by the first motor generator MG1 to maintain (lift) the engine speed. There are cases where the engine speed is made substantially constant.

-EGR valve failure detection-
The ECU 100 is configured to perform primary determination and secondary determination, and determine the state of the EGR valve 72 (normal, open fixed or closed fixed) based on the results of the primary determination and the secondary determination. .

[Primary judgment]
The primary determination is performed in order to determine the possibility that the EGR valve 72 is stuck open, and the engine in the operation region where the EGR device 7 does not recirculate the exhaust gas (the EGR valve 72 is closed). 1 based on the combustion state of 1.

  Here, an example of the operation region of the engine 1 in which the EGR device 7 does not recirculate the exhaust gas is when the catalyst is warmed up. The catalyst warm-up is a process for activating the three-way catalyst 19 at an early stage when the engine 1 is cold started. In the engine 1, the temperature of the exhaust gas is increased by retarding the ignition timing by the igniter 16a. Is done by. At this time, if the EGR valve 72 has not failed, the EGR valve 72 is closed by the stepping motor 73.

  Further, the combustion state of the engine 1 is determined based on ΔA / F and ΔNe in a predetermined period (for example, 100 [rev]). ΔA / F is a value obtained by integrating the absolute value of the change amount of the air-fuel ratio determined based on the detection result of the air-fuel ratio sensor 107, and ΔNe is determined based on the detection result of the crank position sensor 102. It is a value obtained by integrating the absolute value of the change amount of the engine speed.

  Specifically, when ΔA / F and ΔNe in a predetermined period are equal to or greater than a predetermined value, the ECU 100 may cause the air-fuel ratio and the engine speed to hunt due to misfire. It is determined that it is unstable (the primary determination is abnormal). On the other hand, ECU 100 determines that the combustion state of engine 1 is not unstable (primary determination is normal) when ΔA / F or ΔNe in a predetermined period is less than a predetermined value.

  That is, the ECU 100 determines that the EGR valve 72 may be stuck open when the primary determination during catalyst warm-up is abnormal, and the primary determination during catalyst warm-up is normal. , It is determined that the EGR valve 72 is not openly fixed.

[Secondary judgment]
The secondary determination is performed to determine whether or not the EGR valve 72 is in a fixed state, and the intake manifold pressure when the EGR valve 72 is forcibly opened and closed with the engine speed kept substantially constant. Based on changes in

  FIG. 4 is a timing chart showing the relationship among the engine speed, the EGR valve opening / closing command, and the intake manifold pressure in the secondary determination. FIG. 4 shows a case where the EGR valve 72 is not in a fixed state. Next, with reference to FIG. 4, the secondary determination when the EGR valve 72 is not in a fixed state will be described.

  First, a closing command is output from the ECU 100 to the stepping motor 73, and the stepping motor 73 is driven to close the EGR valve 72. Further, the engine speed is controlled to be substantially constant by the ECU 100.

  Then, the intake manifold pressure at the time point t1 is acquired by the ECU 100. Thereafter, an opening command is output from the ECU 100 to the stepping motor 73, and the stepping motor 73 is driven to open the EGR valve 72.

  At this time, since the EGR valve 72 is not in the fixed state in the example of FIG. 4, the exhaust gas is recirculated to the intake manifold 11b through the EGR passage 71 by opening the EGR valve 72, so that the intake manifold pressure is increased. Be raised.

  Thereafter, at a time point t2 when a predetermined period has elapsed, the ECU 100 acquires the intake manifold pressure at the time point t2. Thereafter, a closing command is output from the ECU 100 to the stepping motor 73, and the stepping motor 73 is driven to close the EGR valve 72. For this reason, since the recirculation of the exhaust gas is stopped by closing the EGR valve 72, the intake manifold pressure is lowered.

  Thereafter, at the time t3 when the predetermined period has elapsed, the ECU 100 acquires the intake manifold pressure at the time t3.

  Then, the ECU 100 calculates a change amount ΔP of the intake manifold pressure when a forced opening / closing command is issued based on the acquired intake manifold pressure. For example, the ECU 100 calculates an average of the intake manifold pressure at the time points t1 and t3 (average intake manifold pressure at the time of closing command), and calculates the intake manifold pressure at the time point t2 (intake manifold pressure at the time of opening command) and the average intake manifold pressure at the time of closing command. The change amount ΔP is calculated from the difference between the two.

  The ECU 100 considers that the EGR valve 72 is operating when the intake manifold pressure change ΔP is greater than or equal to a predetermined value (for example, 1 [kPa]) (in the example of FIG. 4). When it is determined that the valve 72 is not in a fixed state (secondary determination is normal) and the change amount ΔP of the intake manifold pressure is less than a predetermined value, it is considered that the EGR valve 72 is not operating. It is determined that the valve 72 is in a fixed state (secondary determination is abnormal).

  Here, in order to perform the secondary determination, it is necessary to keep the engine speed substantially constant in order to suppress fluctuations in the intake manifold pressure due to other than opening / closing of the EGR valve 72. In the hybrid vehicle HV according to this embodiment, the engine 1 is driven by the first motor generator MG1 to maintain the engine speed (ie, lift) during the fuel cut in which the fuel injection from the injector 15 is stopped. The rotational speed is controlled to be substantially constant. Note that the control of making the engine speed substantially constant by the first motor generator MG1 during the fuel cut is performed, for example, to prepare for restart of the engine 1 that is intermittently operated when the vehicle speed is high.

  Further, in the present embodiment, when the primary determination is abnormal and the power from the engine 1 is not requested, the charge control is forcibly performed even if the SOC of the battery 300 does not decrease to a predetermined value. As a result, the engine speed is controlled to be substantially constant. In this charging control, the load of the engine 1 is made substantially constant, and electric power is generated by driving the first motor generator MG1 with the power of the engine 1.

[Failure detection flow]
FIG. 5 is a flowchart showing an example of failure detection of the EGR valve. Next, a method for determining the state of the EGR valve 72 will be described with reference to FIG. The following steps are executed by the ECU 100.

  First, in step ST1, a primary determination is performed during catalyst warm-up. Specifically, it is determined whether ΔA / F and ΔNe in a predetermined period during catalyst warm-up are equal to or greater than a predetermined value. If it is determined that ΔA / F and ΔNe are equal to or greater than the predetermined values, the combustion state of the engine 1 is unstable (the primary determination is abnormal), and therefore the EGR valve 72 is stuck open. There is a possibility that the process proceeds to step ST2. On the other hand, if it is determined that ΔA / F or ΔNe is less than the predetermined value, the combustion state of the engine 1 is not unstable (the primary determination is normal), and therefore the EGR valve 72 is stuck open. Instead, there is a possibility of closed adhesion, and the process proceeds to step ST9.

  Next, in step ST2, it is determined whether the engine 1 is stopped or the engine 1 is idling. Then, when the engine 1 is stopped or the engine 1 is idling, the power from the engine 1 is not requested, and the process proceeds to step ST3. On the other hand, when the engine 1 is not stopped or the engine 1 is not idling, the process proceeds to step ST7.

  Next, in step ST3, charge control is forcibly performed. This charging control is performed by driving first motor generator MG1 with the power of engine 1. That is, when the engine 1 is stopped, it is restarted. At this time, the load of the engine 1 is substantially constant, and the engine speed is controlled to be substantially constant.

  Next, in step ST4, secondary determination is performed. Specifically, a change amount ΔP of the intake manifold pressure when the opening / closing command is forcibly issued to the stepping motor 73 is calculated, and it is determined whether or not the change amount ΔP of the intake manifold pressure is less than a predetermined value. If the change amount ΔP of the intake manifold pressure is less than the predetermined value, the EGR valve 72 is in a fixed state (secondary determination is abnormal), so in step ST5, the EGR valve 72 is open fixed. Is determined and the process proceeds to return. On the other hand, if the change amount ΔP of the intake manifold pressure is equal to or larger than the predetermined value, the EGR valve 72 is not in a fixed state (secondary determination is normal), and therefore the EGR valve 72 is normal in step ST6. Is determined and the process proceeds to return. In this case, it is considered that the combustion state is unstable due to factors other than the EGR valve 72.

  When engine 1 is not stopped or engine 1 is not idling (step ST2: No), in step ST7, whether or not the engine speed is made substantially constant by first motor generator MG1 by fuel cut. Is judged. If it is determined by fuel cut that the engine speed is substantially constant, the process proceeds to step ST8. On the other hand, if it is determined that the engine speed is not substantially constant due to the fuel cut, for example, power is output from the engine 1, and the process returns to step ST2. That is, the secondary determination is performed when the power from the engine 1 is not requested.

  Next, in step ST8, secondary determination is performed. If the change amount ΔP of the intake manifold pressure is less than the predetermined value, the EGR valve 72 is in a fixed state (secondary determination is abnormal), so in step ST5, the EGR valve 72 is open fixed. Is determined and the process proceeds to return. On the other hand, if the change amount ΔP of the intake manifold pressure is equal to or larger than the predetermined value, the EGR valve 72 is not in a fixed state (secondary determination is normal), and therefore the EGR valve 72 is normal in step ST6. Is determined and the process proceeds to return. In this case, it is considered that the combustion state is unstable due to factors other than the EGR valve 72.

  When the primary determination is normal (step ST1: No), there is a possibility that the EGR valve 72 is closed and fixed. Therefore, in step ST9, it is determined whether or not the engine speed is made substantially constant by the first motor generator MG1 by fuel cut. If it is determined that the engine speed is substantially constant due to the fuel cut, the process proceeds to step ST10. On the other hand, if it is determined by fuel cut that the engine speed is not substantially constant, step ST9 is repeated.

  Next, in step ST10, secondary determination is performed. If the change amount ΔP of the intake manifold pressure is less than the predetermined value, the EGR valve 72 is in a fixed state (secondary determination is abnormal), so in step ST11, the EGR valve 72 is closed and fixed. Is determined and the process proceeds to return. On the other hand, if the change amount ΔP of the intake manifold pressure is equal to or larger than the predetermined value, the EGR valve 72 is not in a fixed state (secondary determination is normal), and therefore the EGR valve 72 is normal in step ST6. Is determined and the process proceeds to return.

-Effect-
In the present embodiment, as described above, whether or not the EGR valve 72 is in the fixed state after performing the primary determination (determination regarding the combustion state of the engine 1) for determining the possibility that the EGR valve 72 is in the open fixed state. When the primary determination and the secondary determination are abnormal by performing the secondary determination (determination regarding the change amount ΔP of the intake manifold pressure when the stepping motor 73 is forcibly commanded to open / close) It can be determined that the EGR valve 72 is open and fixed, and when the primary determination is normal and the secondary determination is abnormal, the EGR valve 72 can be determined to be closed and fixed. Further, when the secondary determination is normal, it can be determined that the EGR valve 72 is normal.

  Further, in the present embodiment, the engine speed is controlled to be substantially constant by controlling the engine speed by forcing charge control, so that the first motor generator MG1 controls the engine speed to be substantially constant in a fuel cut. Secondary determination can be performed without waiting. Thereby, since the state of the EGR valve 72 can be determined early, it is possible to notify the driver of the abnormality of the EGR valve 72 early. Further, since the load for driving the first motor generator MG1 is applied to the engine 1 as compared with the case where the engine speed is controlled to be substantially constant by fuel cut, there is a possibility that the EGR valve 72 may be openly fixed. The deterioration of the combustion state of the engine 1 can be suppressed. Further, since charging is not started during the secondary determination, the load of the engine 1 can be prevented from fluctuating, so that the state of the EGR valve 72 is determined based on the change amount ΔP of the intake manifold pressure. (Fixing) can be determined appropriately.

-Other embodiments-
In addition, embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, the technical scope of the present invention includes all modifications within the scope and meaning equivalent to the scope of the claims.

  For example, in the present embodiment, the case where the present invention is applied to an FF hybrid vehicle has been described. However, the present invention is not limited to this, and an FR (front engine / rear drive) hybrid vehicle or a four-wheel drive hybrid vehicle. It can also be applied to.

  In the present embodiment, the example in which the present invention is applied to a hybrid vehicle equipped with a 4-cylinder gasoline engine has been described. However, the present invention is not limited to this, and a hybrid vehicle equipped with a gasoline engine having any other number of cylinders is described. It is also applicable to. Further, the present invention is not limited to a port injection type gasoline engine, and can be applied to a hybrid vehicle equipped with an in-cylinder direct injection type gasoline engine.

  In this embodiment, an example in which the present invention is applied to a hybrid vehicle equipped with a gasoline engine has been described. However, the present invention is not limited to this, and the present invention is not limited to a hybrid vehicle equipped with another engine (internal combustion engine) such as a diesel engine. Is also applicable.

  Further, in the present embodiment, the example in which the charge control is forcibly performed and the secondary determination is performed only when there is a possibility that the EGR valve 72 is openly fixed (step ST1: Yes) has been described. Instead, when there is a possibility that the EGR valve 72 is closed and stuck (step ST1: No), the charge control may be forcibly performed and the secondary determination may be performed.

  Further, in the present embodiment, an example in which it is determined that the combustion state of the engine 1 is unstable when it is determined that ΔA / F and ΔNe are equal to or larger than predetermined values is not limited to this, but ΔA / F and ΔNe are not limited thereto. When it is determined that / F or ΔNe is equal to or greater than a predetermined value, it may be determined that the combustion state of the engine 1 is unstable. Further, the combustion state of the engine 1 may be determined based on only one of ΔA / F and ΔNe, or the combustion state of the engine 1 may be determined based on other factors.

  Further, in the present embodiment, an example in which the primary determination is performed when the catalyst is warmed up is shown, but the present invention is not limited to this, and the EGR device 7 other than when the catalyst is warmed up is in the operating region of the engine 1 where the exhaust gas is not recirculated. You may make it perform primary determination.

  In the present embodiment, when the battery 300 is in a fully charged state, the charging control may not be forcibly performed. In this case, the secondary determination may be performed when the engine speed is controlled to be substantially constant by the first motor generator MG1 in the fuel cut.

  The present invention is applicable to an EGR valve failure detection device applied to a hybrid vehicle, and more specifically, to a hybrid vehicle equipped with an internal combustion engine (engine) equipped with an EGR device and an electric motor (motor generator or the like). The present invention can be effectively used for an applied EGR valve failure detection device.

1 engine (internal combustion engine, drive source)
11 intake passage 12 exhaust passage 3 power split mechanism (planetary gear mechanism)
S3 Sun gear P3 Pinion gear R3 Ring gear CA3 Planetary carrier 4 Reduction mechanism 61 Drive shaft (drive shaft)
6L, 6R Drive wheel (front wheel)
7 EGR device 71 EGR passage 72 EGR valve 73 Stepping motor (drive unit)
100 ECU (EGR valve failure detection device)
300 battery (power storage device)
MG1 first motor generator (drive source, first electric motor)
MG2 Second motor generator (drive source, second electric motor)
HV hybrid vehicle

Claims (3)

An EGR device having an EGR passage for returning a part of exhaust gas discharged to the exhaust passage to the intake passage, an EGR valve provided in the EGR passage, and a drive unit for opening and closing the EGR valve is provided. In an EGR valve failure detection apparatus in a hybrid vehicle equipped with a plurality of drive sources including an internal combustion engine,
When the combustion state of the internal combustion engine is unstable in the operation region where the exhaust gas is not recirculated to the intake passage, the intake manifold is opened when the EGR valve is opened by the drive unit in a state where charge control is performed. An EGR valve failure detection device configured to determine a state of the EGR valve based on a change in pressure. In the EGR valve failure detection device according to claim 1,
When the combustion state of the internal combustion engine is not unstable in the operation region where the exhaust gas is not recirculated to the intake passage, the EGR is changed based on the change in the intake manifold pressure when the EGR valve is opened by the drive unit. An EGR valve failure detection device configured to determine a state of a valve. In the EGR valve failure detection device according to claim 1 or 2,
The hybrid vehicle has three shafts: the internal combustion engine, a first electric motor capable of inputting and outputting power, an output shaft of the internal combustion engine, a rotation shaft of the first motor, and a drive shaft connected to drive wheels. A planetary gear mechanism in which three rotating elements are connected, a second electric motor capable of inputting / outputting power to / from the drive shaft, and a power storage device capable of exchanging electric power with the first electric motor and the second electric motor,
In the charging control, the EGR valve failure detection device is characterized in that the electric power generated by the first electric motor rotated by the power of the internal combustion engine is charged in the power storage device.

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