JP2008157095A - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent decrease in engine performance, when there is an abnormality in a function relating to combustion rotation of an engine in a hybrid vehicle. <P>SOLUTION: A control means 10 for a hybrid vehicle having both of an engine 1 and an electric motor 3 as drive sources includes: a combustion rotation function diagnosing means 10 during engine stop, diagnosing, during engine stop, whether there is an abnormality in a function of the combustion rotation of the engine 1; and a hybrid control means 10 performing an operation control of the engine 1 and the electric motor 3 based on the diagnosis of the combustion rotation function diagnosing means 10 during engine stop. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control device, and more particularly, to a control device that performs control for preventing further deterioration in engine performance when there is an abnormality in a function for rotating an engine for a hybrid vehicle.

2. Description of the Related Art In a vehicle using only an engine as a drive source, a control device including means for diagnosing a function for rotating the engine by combustion is generally known. For example, in Patent Document 1, as a technique for diagnosing the fuel injection device even when the engine is stopped, a low-level determination current that does not operate the fuel injection valve is applied to the fuel injection device, and the current value at that time is A technique for determining whether there is an abnormality by detecting is disclosed.
JP-A-10-252539

  By the way, in a general vehicle using only the engine as a drive source, the starter has a low output, and its cranking rotation speed is about 200 rpm at most. In addition, cranking using the starter is limited to when the vehicle is stopped.

  Therefore, if an abnormality that leads to increased friction occurs, cranking itself becomes impossible, or even if cranking can be performed, a sufficient rotational speed cannot be obtained. Is likely to stop again without generating torque. For this reason, it is unlikely to cause further deterioration in engine performance.

  On the other hand, in a so-called hybrid vehicle having both an engine and an electric motor as drive sources, cranking can be performed using a powerful electric motor, and the cranking rotation speed in this case reaches about 1000 rpm. For this reason, the cranking in a state where an abnormality has occurred may cause further performance degradation to the engine. In addition, there is an opportunity to perform cranking while the vehicle is traveling in order to further increase the output from the driving range where the electric motor travels alone. In this case, if there is a failure in starting the engine, the engine will be started again.

  However, the diagnostic technique described in Patent Document 1 is for a general vehicle using only the engine as a drive source, and measures such as prohibiting cranking after detecting a deterioration in the performance of the combustion injection device. There is no description about. Furthermore, diagnosis of main parts related to engine operation is premised to be performed while the engine is rotating, and cranking itself is not prohibited.

  That is, the diagnostic technique described in Patent Document 1 cannot avoid the above-described problem caused by cranking at a high rotational speed unique to a hybrid vehicle.

  Therefore, an object of the present invention is to provide a control device that can prevent unnecessary restart of the engine when there is an abnormality in the function related to the combustion rotation of the engine in the hybrid vehicle.

  The hybrid vehicle control device of the present invention is a self-diagnosis device for a hybrid vehicle having both an engine and an electric motor as drive sources, and diagnoses whether there is an abnormality in the function for rotating the engine for combustion. An engine stop combustion rotation function diagnosing unit that is performed while the engine is stopped, and a hybrid control unit that performs operation control of the engine and the electric motor based on a diagnosis result of the engine stop combustion rotation function diagnosing unit.

  According to the present invention, an abnormality can be detected before the engine is started. For example, when an abnormality is detected, an unnecessary restart of the engine can be performed by taking measures such as prohibiting the engine from starting. Can be prevented.

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

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle system to which the present embodiment is applied. 1 is an engine, 2 is a transmission, 2a is a differential gear, 3 is an electric motor, 4 is a high-power battery for driving the electric motor (hereinafter simply referred to as a high-power battery), 5 is a power distribution mechanism, and 6 is intake air amount control means. , A crank angle sensor, 8 a vehicle speed sensor as vehicle state detecting means, 9 a wheel, 10 a control unit, 11 a drive shaft, and 12 a fuel injection valve.

  The outputs of the engine 1 and the electric motor 3 are both input to the power distribution mechanism 5 and transmitted to the wheels via the differential gear 2 a and the drive shaft 11 disposed in the case of the transmission 2. The power distribution mechanism 5 includes a planetary gear or a clutch mechanism, and transmits the output of either the engine 1 or the electric motor 3 to the wheels 9. Depending on the state of charge of the high-power battery 4, part or all of the output of the engine 1 is distributed to drive the electric motor 3 in order to cause the electric motor 3 to function as a generator.

  The detected values of the crank angle sensor 7 for detecting the crank angle of the engine 1 and the vehicle speed sensor 8 for detecting the rotational speed of the output shaft of the transmission 2 are the combustion rotation function diagnosis means, the hybrid control means, and the electric running while the engine is stopped. It is input to the control unit 10 as function diagnosis means.

  Here, the control unit 10 will be described with reference to FIG. The control unit 10 includes an engine control unit (ECU) 10a, a hybrid control module (HCM) 10b, and an abnormality determination device 10c. The HCM 10b calculates the driver's required output based on the detected value of the vehicle speed sensor 8, the amount of charge of the high-power battery 4, the driver's accelerator opening detection signal, etc., and in order to satisfy this required output, the engine 1 and The output to be generated by the electric motor 3 is set. Then, the electric motor 3 is driven according to the set output, or a start / stop request signal for the engine 1 is output to the ECU 10a.

  When there is an engine start request, the electric motor 3 cranks the engine 1. For this reason, the starter motor provided in the conventional engine is not provided.

  The ECU 10a adjusts the opening degree of the throttle valve 6 according to the signal from the HCM 10b and the detection values of the crank angle sensor 7 and the vehicle speed detection sensor 8, or according to the injection amount and the injection timing with respect to the fuel injection valve 12. By outputting the injection signal, the output of the engine 1 is controlled. In addition, ECU10a and HCM10b may be comprised integrally.

  The abnormality determination device 10c has a circuit configuration including the transistor 13 as shown in FIG. 3, and outputs a monitor signal corresponding to the current value of the fuel injection valve 12 to the ECU 10a. Whether or not there is an abnormality is determined based on the monitor signal. That is, when the engine 1 is stopped, the transistor 13 is always turned off, so the monitor signal should be “Hi” indicating 12 V. Therefore, the monitor signal is “Lo” even when the engine 1 is stopped. When it becomes, it is determined that there is an abnormality such as disconnection or GND short.

  Next, a control routine for abnormality diagnosis executed by the control unit 10 will be described with reference to the flowchart of FIG.

  In step S110, it is determined whether or not the engine 1 is currently stopped. If it is driving, the process proceeds to step S170, and a hybrid operation is performed in which the driving states of the engine 1 and the electric motor 3 are switched in accordance with the driving state (normal hybrid mode).

  In the normal hybrid mode, as in a general system, a diagnosis of a fuel injection valve, a strong electric system, etc. is performed during engine rotation, and the system status is monitored.

  If the engine 1 is stopped, the process proceeds to step S120.

  In step S120, a self-diagnosis is executed. Here, it is diagnosed whether or not the engine 1 is in a difficult state, that is, a function for rotating the engine 1 by combustion. Specifically, in addition to at least the GND short diagnosis and the disconnection diagnosis for the fuel injection valve 12 described above, whether or not the fuel injection valve 12 is in a state of causing a fuel leak, and the throttle valve 6 being opened An open fixation diagnosis is performed to diagnose whether or not it is fixed. Whether or not the fuel injection valve 12 is in a state where fuel is leaked is determined based on whether or not the fuel injection valve 12 is always energized. If the fuel injection valve 12 is always energized, it is determined that the fuel is leaking.

  In step S130, it is determined whether or not an abnormality has been detected by the above diagnosis. If no abnormality is detected, the process proceeds to step S170. If an abnormality is detected, the process proceeds to step S140.

  In step S140, it is determined whether or not the voltage of the high-power battery 4 is greater than or equal to a predetermined value. If it is equal to or larger than the predetermined value, the process proceeds to step S150, and if it is equal to or smaller than the predetermined value, the process proceeds to step S190 described later. The predetermined value used here is set to a voltage value capable of traveling in the EV mode described later, for example, about 240V.

  In step S150, it is determined whether or not the high voltage system including the electric motor 3 and the high voltage battery 4 is operating normally. If normal, the process proceeds to step S160. On the other hand, if not normal, the process proceeds to step S190. This is because, if there is an abnormality in the electric system including the electric motor 3, there is a problem in traveling in the EV mode described later.

  In step S160, it is determined whether or not the vehicle is traveling. If it is traveling, the process proceeds to step S180, and if it is stopped, the process proceeds to step S190.

  In step S180, cranking is prohibited and the vehicle travels only by the electric motor 3 (EV mode). Thereby, it can prevent that the further performance fall of the engine 1 is caused by cranking. In addition, the driver is notified of the abnormality by a warning display or a warning sound.

  The EV mode release condition is, for example, that the determination result in step S130 is “no abnormality” or the hybrid system is shut down due to a decrease in the charge amount of the high-power battery 4 while the control routine is being repeated. Alternatively, it is assumed that the history of performance degradation has been deleted using an external device at a repair shop or the like.

  In step S190, when there is a next engine start request, the output of the electric motor 3 is limited, and cranking is attempted with the output of a conventional starter (low output cranking mode). Further, similarly to step S180, the driver is notified of the abnormality by a warning display or the like.

  The condition for canceling the low output cranking mode is that the determination result in step S130 is “no abnormality” while the above control routine is being repeated, or a history of performance degradation using an external device at a repair shop or the like. Is deleted.

  If the engine 1 starts combustion rotation, that is, autonomous operation after cranking in step S190, subsequent idle stop may be prohibited. As a result, it becomes equivalent to a conventional vehicle that travels only with the engine, and it is possible to apply a general fail-safe function such as limiting the engine speed regardless of the driver's accelerator operation.

  Alternatively, a starter motor having the same output as that of the conventional one may be provided as an auxiliary, and when the low output cranking mode is entered, the starter motor may be cranked instead of the electric motor 3.

  As described above, when an abnormality is detected in a device related to the operation of the engine 1 such as the fuel injection valve 12 or the electronically controlled throttle or in the high-voltage system, the normal hybrid operation is switched to the EV mode or the low output cranking mode. Thus, evacuation to a repairable place and system protection during evacuation are performed.

  Note that the determinations in steps S140 to S160 are not necessarily performed all, and at least one of them may be performed.

  As described above, according to the present embodiment, the following effects can be obtained.

  For example, like the fuel injection valve 12, a means for diagnosing whether or not there is an abnormality in the function for rotating the engine 1 while the engine is stopped, and based on the diagnosis result, the engine 1 and the electric motor 3 Control means for performing operation control, so that an abnormality can be detected before the engine 1 is started, and thus the system can be protected when an abnormality occurs.

  As a diagnosis of the function for rotating the engine 1 for combustion, in addition to the diagnosis of the fuel injection valve 12, it is determined whether or not the throttle valve 6 is fixed open, so that the system can be protected more reliably. it can.

  The electric motor 3 also has a function as a starter motor for cranking the engine 1. When the control unit 10 determines that the function for rotating the combustion of the engine 1 is abnormal, the cranking is performed when the engine is started. Since the output of the electric motor 3 is reduced so that the rotational speed is about the same as a conventional general starter (low cranking mode), further performance deterioration due to cranking of the engine 1 can be prevented.

  When the engine 1 starts combustion rotation by cranking in the low cranking mode, the subsequent idle stop is prohibited, so that the state is the same as that of a general vehicle that runs only with the engine. Thereby, the generally known fail-safe function can be applied as it is.

  As a result of the diagnosis of the function for rotating the engine 1 or the strong electric system function, if any function is diagnosed as abnormal, the low cranking mode or the Since the normal one of the EV modes is selected, it is possible to self-propel to a repair shop or the like, and further performance degradation can be prevented.

  A second embodiment will be described.

  In this embodiment, the system configuration is the same as that of the first embodiment, but the control routine for abnormality diagnosis is different. The control routine of this embodiment will be described with reference to the flowchart of FIG.

  In step S210, it is determined whether or not the engine 1 is currently stopped. If it is driving, the process proceeds to step S270, and a hybrid operation is performed in which the driving states of the engine 1 and the electric motor 3 are switched according to the driving state (normal hybrid mode).

  If the engine 1 is stopped, the process proceeds to step S220.

  In step S220, a self-diagnosis is executed. In addition to the diagnosis similar to step S120 in FIG. 4, the self-diagnosis here includes whether or not there is an abnormality in the high-power system including the electric motor 3 and the high-power battery 4, for example, the power supply voltage has decreased, Diagnosis is also performed.

  In step S230, it is determined whether or not an abnormality is detected by the above diagnosis. If no abnormality is detected, the process proceeds to step S270. If an abnormality is detected, the process proceeds to step S290.

  In step S290, the low cranking mode is switched as in step S190 of FIG. Note that step S290 is based on the assumption that the system elements that were not subjected to abnormality diagnosis in step S230 are normal. That is, elements that are not targeted for diagnosis in step S120, such as water temperature, oil temperature, exhaust temperature, etc., are diagnosed by another control routine, and depending on the diagnosis result, the low cranking mode is not necessarily switched. .

  As described above, according to the present embodiment, diagnosis is performed for at least one of the function for causing the engine 1 to burn and rotate while the engine 1 is stopped and the high-power system function. When it is diagnosed, since it is fixed to the low cranking mode, it is possible to self-propel to a repair shop or the like while preventing further deterioration in the performance of the engine 1.

  A third embodiment will be described.

  In this embodiment, the system configuration is the same as that of the first embodiment, but the control routine for abnormality diagnosis is different. The control routine of this embodiment will be described with reference to the flowchart of FIG.

  In step S310, it is determined whether or not the engine 1 is currently stopped. If it is driving, the process proceeds to step S370, and a hybrid operation is performed in which the driving states of the engine 1 and the electric motor 3 are switched according to the driving state (normal hybrid mode).

  If the engine 1 is stopped, the process proceeds to step S320.

  In step S320, a self-diagnosis is executed. In addition to the diagnosis similar to step S120 in FIG. 4, the self-diagnosis here is an element that does not directly affect the engine start, for example, an exhaust system sensor such as an exhaust temperature sensor, an air-fuel ratio sensor, or a catalyst heater. Diagnosis of heaters and heaters.

  In step S330, it is determined whether or not an abnormality is detected by the above diagnosis. If no abnormality is detected, the process proceeds to step S370. If an abnormality is detected, the process proceeds to step S380.

  In step S380, the vehicle is switched to traveling in the EV mode as in step S180 of FIG. Note that step S380 is based on the assumption that the system elements that were not targeted for abnormality diagnosis in step S330 are normal. That is, the elements that are not targeted for diagnosis in step S320, such as water temperature and oil temperature, are diagnosed by another control routine, and the EV mode is not necessarily switched depending on the diagnosis result.

  As described above, in the present embodiment, at least one of the function for rotating and rotating the engine 1 while the engine 1 is stopped and the exhaust sensor is diagnosed, and it is diagnosed that any of the functions is abnormal. In such a case, since the EV mode is fixed, it is possible to self-propel to a repair shop or the like while preventing further deterioration of the performance of the engine 1. In addition, the engine 1 is not started in a state where the performance is deteriorated. Thereby, deterioration of exhaust performance can be prevented.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

1 is a schematic configuration diagram of a system to which a first embodiment is applied. It is a connection diagram of the system of a 1st embodiment. It is a figure showing the example of an abnormality detection means. It is a flowchart of the control routine for abnormality diagnosis of 1st Embodiment. It is a flowchart of the control routine for abnormality diagnosis of the second embodiment. It is a flowchart of the control routine for abnormality diagnosis of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 3 Electric motor 4 High power battery 5 Power distribution mechanism 6 Throttle valve 7 Crank angle sensor 8 Vehicle speed sensor 9 Wheel 10 Control unit 10a Engine control unit (ECU)
10b Hybrid control module (HCM)
11 Drive shaft 12 Fuel injection valve 13 Transistor

Claims (10)

A control device for a hybrid vehicle having an engine and an electric motor as drive sources,
A combustion rotation function diagnosis means during engine stop for diagnosing whether or not there is an abnormality in the function for rotating the engine for combustion; and
Hybrid control means for controlling the operation of the engine and the electric motor based on the diagnosis result of the engine rotation combustion rotation function diagnosis means;
A control device for a hybrid vehicle comprising:   2. The hybrid vehicle control device according to claim 1, wherein the engine rotation combustion rotation function diagnosis unit diagnoses at least a function related to fuel injection as a diagnosis of a function for rotating the engine for combustion. 3. .   The engine rotation combustion rotation function diagnosing means diagnoses whether or not the fuel injection valve is in a state where the fuel can be leaked. If the fuel injection valve is in a state where the fuel can leak, the function for rotating the engine for combustion is abnormal. The hybrid vehicle control device according to claim 2, wherein diagnosis is performed.   4. The engine rotation combustion rotation function diagnosing means diagnoses that fuel leakage is possible when the fuel injection valve is open even when the engine is stopped. The control apparatus for hybrid vehicles described in 2. An intake air amount adjusting means for adjusting the intake air amount of the engine;
5. The engine stop diagnosis device diagnoses a function related to intake air amount control as a diagnosis of a function for rotating the engine for combustion. 6. Control device for hybrid vehicle. A throttle valve is provided as the intake air amount control means,
The engine rotation combustion rotation function diagnosing means diagnoses that there is an abnormality in the function related to the intake air amount control when the throttle valve is stuck in an open state even when the engine is stopped. The hybrid vehicle control device according to claim 5. The electric motor also has a function as a starter motor for cranking the engine,
The hybrid control means is configured to function as a starter for the electric motor so that the cranking rotational speed is equal to or less than a predetermined value when the engine is started when the combustion rotational function diagnosis means during engine stop diagnoses that there is an abnormality. The hybrid vehicle control device according to claim 1, wherein the output is reduced.   The hybrid vehicle according to claim 7, wherein the hybrid control means prohibits a subsequent idle stop when the engine starts combustion rotation by cranking in a state where the output is reduced. Control device. Electric running function diagnosis means for diagnosing whether there is an abnormality in the function related to running by the electric motor;
Vehicle state detection means for detecting the driving state of the vehicle;
With
When either of the engine rotation combustion rotation function diagnosis unit and the electric travel function diagnosis unit diagnoses that the hybrid control unit is abnormal, the hybrid control unit determines whether the engine or the engine based on the diagnosis result and the vehicle state The hybrid vehicle control device according to claim 7, wherein traveling by only the normal one of the electric motors is selected. The electric running function diagnosing means diagnoses at least the battery voltage for driving the electric motor, the presence / absence of an abnormality in the strong electric system function related to the driving of the electric motor,
The hybrid vehicle control device according to claim 9, wherein the vehicle state detection unit detects at least a vehicle speed as a driving state of the vehicle.