Control system for hybrid vehicles

Abstract

To provide a controller of a hybrid vehicle which can increase possibility where abnormality diagnosis is completed earlier and can decrease frequency of motoring state during constant speed traveling to improve fuel consumption.SOLUTION: Abnormality diagnosis of an abnormality diagnosis part comprises: a first abnormality diagnosis (step S2) which performs abnormality diagnosis during fuel cut at the time of deceleration when water temperature is less than a prescribed water temperature or intake air temperature is less than a prescribed intake air temperature; a second abnormality diagnosis (step S4) which performs abnormality diagnosis during fuel cut at the time of deceleration when the water temperature is the prescribed water temperature or more and the intake air temperature is the prescribed intake air temperature or more; and a third abnormality diagnosis (step S5) which performs abnormality diagnosis during motoring state where the motor rotates an internal combustion engine to travel after the lapse of a constant time after starting the hybrid vehicle and when the first abnormality diagnosis and the second abnormality diagnosis are not completed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle.

Background Art

[0002] Patent Document 1 describes a technique for detecting the clogging amount of an EGR passage based on the change amount of the intake air amount when the EGR valve is opened and closed in a state where the EGR passage is open, and determining an abnormality of the EGR passage from the detection result.

[0003] Also, Patent Document 1 describes a technique for detecting the clogging amount of an EGR passage based on the change amount of the pressure in the intake manifold when the EGR valve is opened and closed in a state where the EGR passage is open, and determining an abnormality of the EGR passage from the detection result.

[0004] In the technique described in Patent Document 1, the abnormality detection conditions for performing the abnormality detection of the EGR passage include that the vehicle is decelerating or that the internal combustion engine has been warmed up, and the abnormality detection is performed when such abnormality detection conditions are satisfied.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the technology described in Patent Document 1 had the problem that abnormality diagnosis could not be performed until the internal combustion engine was fully warmed up, thus preventing the diagnosis from being completed early. On the other hand, in hybrid vehicles equipped with a motor for driving, abnormality diagnosis can be performed without waiting for an opportunity for fuel cut-off during deceleration by putting the internal combustion engine into a motoring state where the motor drives it, but there was a problem that fuel efficiency deteriorated as the frequency of the motoring state increased.

[0007] Therefore, the present invention aims to provide a control device for a hybrid vehicle that can greatly increase the possibility of completing abnormality diagnosis early and improve fuel efficiency by reducing the frequency of motoring during constant-speed driving. [Means for solving the problem]

[0008] One aspect of the invention of a control device for a hybrid vehicle that solves the above problems is a control device for a hybrid vehicle that includes an internal combustion engine and a motor as a drive source for the vehicle, and a clutch provided between the internal combustion engine and the motor, and which is capable of EV driving by stopping the internal combustion engine and disengaging the clutch and driving with the motor, comprising: a drive control unit that controls the vehicle to perform EV driving during constant speed driving, an abnormality diagnosis unit that performs abnormality diagnosis of an on-board device mounted on the vehicle, a water temperature detection unit that detects the water temperature of the coolant of the internal combustion engine, and an intake air temperature detection unit that detects the intake air temperature of the intake air supplied to the internal combustion engine, wherein the abnormality diagnosis performed by the abnormality diagnosis unit is that the water temperature is below a predetermined water temperature or The invention is characterized by comprising: a first abnormality diagnosis performed during deceleration fuel cut-off, provided that the intake air temperature is below a predetermined intake air temperature; a second abnormality diagnosis performed during deceleration fuel cut-off, provided that the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature; and a third abnormality diagnosis performed after a certain period of time has elapsed since the start of the hybrid vehicle and the first and second abnormality diagnoses have not been completed, by stopping the fuel supply to the internal combustion engine, engaging the clutch, and putting the vehicle into a motoring state in which the internal combustion engine is driven by the motor, and then performing an abnormality diagnosis of the onboard device. [Effects of the Invention]

[0009] Thus, according to the present invention, it is possible to significantly increase the possibility of completing abnormality diagnosis early, and to provide a control device for a hybrid vehicle that can reduce the frequency of motoring during constant-speed driving and improve fuel efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a diagram showing the configuration of a vehicle equipped with a control device for a hybrid vehicle according to one embodiment of the present invention. [Figure 2] Figure 2 is a diagram showing the configuration of a control device for a hybrid vehicle according to one embodiment of the present invention. [Figure 3]Figure 3 is a flowchart illustrating the abnormality diagnosis operation by a control device for a hybrid vehicle according to one embodiment of the present invention. [Modes for carrying out the invention]

[0011] A control device for a hybrid vehicle according to one embodiment of the present invention comprises an internal combustion engine and a motor as a drive source for the vehicle, and a clutch provided between the internal combustion engine and the motor, and is a control device for a hybrid vehicle capable of EV driving by stopping the internal combustion engine and disengaging the clutch and driving with the motor, comprising a drive control unit that controls to perform EV driving during constant speed driving, an abnormality diagnosis unit that performs abnormality diagnosis of on-board devices mounted on the vehicle, a water temperature detection unit that detects the water temperature of the coolant of the internal combustion engine, and an intake air temperature detection unit that detects the intake air temperature of the intake air supplied to the internal combustion engine, wherein the abnormality diagnosis performed by the abnormality diagnosis unit is when the water temperature is below a predetermined water temperature or The invention is characterized by including: a first abnormality diagnosis performed during deceleration fuel cut-off, provided that the intake air temperature is below a predetermined intake air temperature; a second abnormality diagnosis performed during deceleration fuel cut-off, provided that the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature; and a third abnormality diagnosis performed after a certain period of time has elapsed since the hybrid vehicle started and the first and second abnormality diagnoses have not been completed, by stopping the fuel supply to the internal combustion engine, engaging the clutch, and entering a motoring state in which the vehicle is driven by the motor to accompany the internal combustion engine, and then performing an abnormality diagnosis of the onboard device. As a result, the control device for a hybrid vehicle according to one embodiment of the present invention can greatly increase the possibility of completing abnormality diagnosis early, and can improve fuel efficiency by reducing the frequency of the motoring state during constant speed driving. [Examples]

[0012] Hereinafter, with reference to the drawings, a control device for a hybrid vehicle according to an embodiment of the present invention will be described in detail.

[0013] In Figure 1, a hybrid vehicle 1 equipped with a control device according to one embodiment of the present invention comprises an internal combustion engine 10 and a motor 13 as the driving source of the vehicle, and a clutch 11 provided between the internal combustion engine 10 and the motor 13.

[0014] The hybrid vehicle 1 is equipped with a transmission (indicated as T / M in the figure) 12, which transmits the rotation transmitted from the internal combustion engine 10 via a clutch 11 to the drive wheels (not shown) after shifting the speed.

[0015] The motor 13 is connected to the transmission 12, and the power of the motor 13 is transmitted to the drive wheels via the transmission 12.

[0016] The hybrid vehicle 1 configured in this way can operate in EV mode by stopping the internal combustion engine 10 and disengaging the clutch 11, and then driving using the motor 13. In other words, the hybrid vehicle 1 can operate in EV mode without the stopped internal combustion engine 10 being pulled along by the motor 13. The position of the motor 13 may be closer to the internal combustion engine 10 than to the clutch 11.

[0017] The internal combustion engine 10 is a four-cycle engine in which the piston performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke during two reciprocating motions within the cylinder. The piston housed in each cylinder is connected to the crankshaft via a connecting rod. The connecting rod converts the reciprocating motion of the piston into the rotational motion of the crankshaft. The internal combustion engine 10 generates driving force by causing the piston to reciprocate through the combustion of a fuel-air mixture in the combustion chamber within the cylinder, and by rotating the crankshaft via the connecting rod.

[0018] The hybrid vehicle 1 includes a water temperature detection unit 21 for detecting the water temperature of the coolant of the internal combustion engine 10, and an intake air temperature detection unit 22 for detecting the intake air temperature of the intake air supplied to the internal combustion engine 10.

[0019] The hybrid vehicle 1 includes an exhaust gas recirculation device (denoted as EGR in the figure) 25. The exhaust gas recirculation device 25 has an EGR passage (not shown) that connects the exhaust passage and the intake passage of the internal combustion engine 10, and an EGR valve (not shown) that opens and closes this EGR passage, and recirculates an amount of exhaust gas corresponding to the opening degree of the EGR valve to the intake passage.

[0020] The hybrid vehicle 1 includes a rear O2 sensor 24. The rear O2 sensor 24 is provided on the downstream side of a catalyst (not shown) in the exhaust passage and detects the oxygen concentration in the exhaust gas. The exhaust gas recirculation device 25 and the rear O2 sensor 24 constitute the in-vehicle device in the present invention. Incidentally, the hybrid vehicle 1 includes a front O2 sensor (not shown), and the front O2 sensor is provided on the upstream side of the catalyst in the exhaust passage.

[0021] The control device 30 is constituted by a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

[0022] In the ROM of the control device 30, a program for causing the computer unit to function as the control device 30 is stored together with various control constants, various maps, etc. That is, when the CPU executes the program stored in the ROM, the computer unit functions as the control device 30.

[0023] In FIG. ⑵, in addition to the above-described water temperature detection unit 21 and intake air temperature detection unit 22, a vehicle speed detection unit 23 is connected to the input port of the control device 30. The vehicle speed detection unit 23 detects the vehicle speed based on the rotational speed of the drive wheels or the like and outputs a detection signal to the control device 30.

[0024] On the other hand, the internal combustion engine 10, the motor 13, the clutch 11, the rear O2 sensor 24, and the exhaust gas recirculation device 25 are connected to the output port of the control device 30.

[0025] The exhaust gas recirculation system 25 may experience abnormalities such as blockage of the EGR passage due to deposits, or abnormal opening and closing of the EGR valve. Additionally, the rear O2 sensor 24 may experience abnormal responsiveness.

[0026] Therefore, it is necessary to perform abnormality diagnoses on the exhaust recirculation device 25 and the rear O2 sensor 24 at appropriate intervals to determine whether or not there is an abnormality. In this embodiment, abnormality diagnoses are performed for each driving cycle from system startup to shutdown of the hybrid vehicle 1. Furthermore, in order to avoid impairing drivability, the abnormality diagnoses of the exhaust recirculation device 25 and the rear O2 sensor 24 must be performed when fuel injection is not being performed in the internal combustion engine 10.

[0027] Abnormality diagnosis of the exhaust recirculation device 25 and the rear O2 sensor 24 can be performed during deceleration fuel cut after the internal combustion engine 10 has warmed up, in the engine driving mode where the vehicle is driven by the engine torque of the internal combustion engine 10. Deceleration fuel cut is a mechanism that interrupts fuel injection when the accelerator pedal is not pressed and resumes fuel injection when the engine speed drops to a predetermined recovery speed. Deceleration fuel cut is performed when driving downhill, etc., and this can reduce fuel consumption.

[0028] Alternatively, abnormality diagnosis of the exhaust recirculation device 25 and the rear O2 sensor 24 can be performed in the motoring state. The motoring state is a state in which the fuel supply to the internal combustion engine 10 is stopped and the clutch 11 is engaged, and the vehicle is driven by the motor 13 to move the internal combustion engine 10, and is one form of EV driving. Normal EV driving is performed with the clutch 11 disengaged to improve fuel efficiency by avoiding the internal combustion engine 10, from being driven by the motor 13 when the fuel supply is stopped, but in the motoring state, it is performed with the clutch 11 engaged.

[0029] Here, if the diagnostic conditions for performing abnormality diagnosis of the exhaust recirculation device 25 and the rear O2 sensor 24 are met only after the internal combustion engine 10 has finished warming up and while deceleration fuel cut is in effect, then it is necessary to wait until the engine is warmed up and then wait for an opportunity for deceleration fuel cut to occur before performing the abnormality diagnosis. As a result, even if a predetermined amount of time has elapsed after the hybrid vehicle 1 system starts up, the diagnostic conditions may not be met, and the abnormality diagnosis may not be completed early.

[0030] Therefore, in this embodiment, the hybrid vehicle 1 is configured so that the conditions for performing an abnormality diagnosis are met even before the internal combustion engine 10 has finished warming up. Furthermore, in this embodiment, when the predetermined conditions for performing an abnormality diagnosis are met, the hybrid vehicle 1 is configured to perform an abnormality diagnosis by putting the exhaust recirculation device 25 and the rear O2 sensor 24 into a motoring state, which is the same state as when fuel is cut off during deceleration. However, in the motoring state, the load that moves the internal combustion engine 10 acts on the motor 13, causing the motor 10 to consume more power than in normal EV driving. Also, increasing the frequency of the motoring state increases the fuel consumed by the internal combustion engine 10 for power generation. For this reason, it is desirable to keep the frequency of the motoring state low. In addition, during constant speed driving, such as cruising after acceleration has finished, it is desirable to disengage the clutch 11 and perform normal EV driving in order to reduce fuel consumption.

[0031] The control device 30 includes a drive control unit 31, which controls the vehicle to operate in EV mode while the vehicle speed is constant. In other words, the control device 30 stops the operation of the internal combustion engine 10 and drives the vehicle using the motor torque of the motor 13 when cruising after acceleration is complete. This reduces fuel consumption by the internal combustion engine 10 and improves fuel efficiency.

[0032] The control device 30 includes an abnormality diagnosis unit 32, which performs abnormality diagnosis of the exhaust recirculation device 25 and the rear O2 sensor 24 installed in the hybrid vehicle 1. The abnormality diagnosis performed by the abnormality diagnosis unit 32 includes a first abnormality diagnosis, a second abnormality diagnosis, and a third abnormality diagnosis.

[0033] The first abnormality diagnosis involves performing an abnormality diagnosis of the exhaust gas recirculation device 25 and the rear O2 sensor 24 during deceleration fuel cut, provided that the water temperature is below a predetermined water temperature or the intake air temperature is below a predetermined intake air temperature. Deceleration fuel cut is the temporary interruption of fuel injection in the internal combustion engine 10 when the accelerator pedal is not pressed, such as when driving downhill.

[0034] The abnormality diagnosis of the exhaust gas recirculation device 25 involves opening and closing the EGR valve to detect the pressure difference in the intake path (e.g., intake manifold), and diagnosing that an abnormality has occurred due to a blockage in the EGR passage if this pressure difference falls below a specified value. The abnormality diagnosis of the rear O2 sensor 24 involves diagnosing the responsiveness of the rear O2 sensor 24 and determining whether there is an abnormality in its responsiveness. For example, if the time it takes for the signal voltage of the rear O2 sensor 24 to change from rich to lean during deceleration fuel cut-off exceeds a specified time, it is determined that the responsiveness of the rear O2 sensor 24 is abnormal.

[0035] When the abnormality diagnosis unit 32 performs the first abnormality diagnosis, it determines that the condition is normal if the predetermined diagnostic criteria are met, and determines that the diagnosis is incomplete if the diagnostic criteria are not met.

[0036] The first abnormality diagnosis is a preliminary diagnosis performed in a vehicle state before the engine warms up, after the internal combustion engine 10 has started but before the water temperature reaches a predetermined temperature and the intake air temperature reaches a predetermined intake air temperature. In the first abnormality diagnosis performed in a vehicle state before the engine warms up, it is not possible to definitively diagnose an abnormality based on the failure to satisfy the diagnostic criteria.

[0037] For example, the exhaust recirculation device 25 is activated only after the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature. Therefore, in such vehicle conditions, it is not possible to definitively diagnose that the exhaust recirculation device 25 is malfunctioning based on the failure to meet the diagnostic criteria.

[0038] Therefore, the abnormality diagnosis unit 32 determines that the diagnosis is incomplete if the diagnostic criteria are not met. The predetermined diagnostic criteria are defined for the rear O2 sensor 24 and the exhaust recirculation device 25, which are the targets of the diagnosis. In the vehicle state in which the first abnormality diagnosis is performed because the engine has not warmed up, it is considered that the conditions for EV driving are not met because the battery temperature of the battery (not shown) is low. Therefore, EV driving is not affected by the performance of the first abnormality diagnosis.

[0039] The second abnormality diagnosis involves performing an abnormality diagnosis of the exhaust gas recirculation device 25 and the rear O2 sensor 24 during deceleration fuel cut, provided that the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature.

[0040] The second abnormality diagnosis is performed during deceleration fuel cut-off, similar to the first abnormality diagnosis, but differs in that it is performed after the engine has warmed up, when both the water temperature and intake air temperature are above a predetermined level.

[0041] The abnormality diagnosis unit 32 performs a preliminary first abnormality diagnosis early on, before the internal combustion engine 10 has finished warming up after starting, and then performs a second abnormality diagnosis after the engine has finished warming up. The second abnormality diagnosis is performed during the fuel cut-off period during deceleration after the engine has finished warming up, and is a diagnostic method commonly used in vehicles.

[0042] When the abnormality diagnosis unit 32 performs the second abnormality diagnosis, it determines that the condition is normal if the diagnostic criteria are met, and abnormal if the diagnostic criteria are not met. Thus, if the diagnostic criteria are not met, the abnormality diagnosis unit 32 determines that the diagnosis is incomplete in the first abnormality diagnosis, but determines that the condition is abnormal in the second abnormality diagnosis.

[0043] The third abnormality diagnosis is performed on the condition that a certain amount of time has elapsed since the start of the hybrid vehicle 1 and the first and second abnormality diagnoses have not been completed. This involves stopping the fuel supply to the internal combustion engine 10, engaging the clutch 11, and putting the vehicle into a motoring state where the internal combustion engine 10 is driven by the motor 13, and then performing abnormality diagnoses of the exhaust recirculation device 25 and the rear O2 sensor 24.

[0044] The conditions for performing the third abnormality diagnosis may be, instead of a certain amount of time having elapsed since the start of the hybrid vehicle 1 and the first and second abnormality diagnoses not being completed, that the cumulative time spent driving at a predetermined vehicle speed (e.g., 40 km / h) or higher after the start of the hybrid vehicle 1 exceeds a predetermined time (e.g., 150 seconds) and the first and second abnormality diagnoses not being completed.

[0045] Furthermore, if the conditions for performing the third abnormal diagnosis are met and fuel cut-off occurs during deceleration, the abnormal diagnosis unit 32 may, instead of performing the third abnormal diagnosis in the motoring state, perform an abnormal diagnosis of the exhaust gas recirculation device 25 and the rear O2 sensor 24 during the fuel cut-off during deceleration, similar to the first and second abnormal diagnoses.

[0046] Thus, if the diagnostic conditions for the first abnormality diagnosis are met, or if the diagnostic conditions for the second abnormality diagnosis are met, the abnormality diagnosis unit 32 waits for an opportunity for deceleration fuel cut-off to occur, and performs the abnormality diagnosis at the timing when deceleration fuel cut-off occurs. On the other hand, if the diagnostic conditions for the third abnormality diagnosis are met, the abnormality diagnosis unit 32 forcibly puts the hybrid vehicle 1 into a motoring state and performs the abnormality diagnosis.

[0047] The abnormality diagnosis operation by the control device of the hybrid vehicle 1 according to this embodiment, configured as described above, will be explained with reference to the flowchart in Figure 3. This abnormality diagnosis operation is repeatedly performed during one driving cycle, from the system startup to the system shutdown of the hybrid vehicle 1, until the diagnostic results for the EGR diagnosis and the rear O2 responsiveness diagnosis are obtained. In this flowchart of the abnormality diagnosis operation, the abnormality diagnosis targeting the exhaust gas recirculation device 25 is called the EGR diagnosis, and the abnormality diagnosis targeting the rear O2 sensor 24 is called the rear O2 responsiveness diagnosis.

[0048] In Figure 3, the control device 30 determines whether the water temperature is low or the intake air temperature is low (step S1). Here, the control device 30 determines that the water temperature is low if the water temperature is below a predetermined water temperature, and determines that the intake air temperature is low if the intake air temperature is below a predetermined intake air temperature.

[0049] If the control device 30 determines in step S1 that the water temperature or intake air temperature is low (YES in step S1), it performs an EGR diagnosis and a rear O2 response diagnosis during deceleration fuel cut (step S2), and then terminates the operation. The diagnosis performed in step S2 based on the conditions in step S1 is the first abnormality diagnosis.

[0050] If the control device 30 determines in step S1 that the water temperature is not low or the intake air temperature is not low (NO in step S1), it determines whether or not it is within a certain time after the start of the internal combustion engine 10 (step S3).

[0051] If the control device 30 determines in step S3 that it is within a certain time since starting (YES in step S3), it performs an EGR diagnosis and a rear O2 response diagnosis during deceleration fuel cut (step S4), and then terminates the operation. The diagnosis performed in step S4 based on the conditions in step S3 is a second abnormality diagnosis.

[0052] If the control device 30 determines in step S3 that it is not within a certain time since starting (NO in step S3), it stops the internal combustion engine 10 and puts the vehicle into a motoring state using the motor 13, performs an EGR diagnosis and a rear O2 responsiveness diagnosis (step S5), and then terminates the operation. The diagnosis performed in step S5 based on the conditions in step S3 is performed such that the first and second abnormality diagnoses have not been completed.

[0053] According to the abnormality diagnosis operation shown in Figure 3, even if the internal combustion engine 10 has not yet warmed up in engine driving mode, a first abnormality diagnosis is performed during deceleration fuel cut-off as a preliminary diagnosis at an early stage before warm-up is complete. Then, once the internal combustion engine 10 has warmed up, a second abnormality diagnosis is performed during deceleration fuel cut-off. If a certain period of time has elapsed without an opportunity to perform the first or second abnormality diagnosis, the vehicle is forcibly put into motoring mode and a third abnormality diagnosis is performed.

[0054] As described above, the hybrid vehicle 1 of this embodiment includes a drive control unit 31 that controls the vehicle to perform EV driving during constant speed driving, and an abnormality diagnosis unit 32 that performs abnormality diagnosis of the exhaust recirculation device 25 and rear O2 sensor 24 mounted on the hybrid vehicle 1. The hybrid vehicle 1 also includes a water temperature detection unit 21 that detects the water temperature of the coolant of the internal combustion engine 10, and an intake air temperature detection unit 22 that detects the intake air temperature of the intake air supplied to the internal combustion engine 10.

[0055] The abnormal diagnosis performed by the abnormal diagnosis unit 32 includes: a first abnormal diagnosis performed during deceleration fuel cut-off, on the condition that the water temperature is below a predetermined water temperature or the intake air temperature is below a predetermined intake air temperature; a second abnormal diagnosis performed during deceleration fuel cut-off, on the condition that the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature; and a third abnormal diagnosis performed during deceleration fuel cut-off, on the condition that a certain amount of time has elapsed since the start of the hybrid vehicle 1 and the first and second abnormal diagnoses have not been completed, on the condition that the fuel supply to the internal combustion engine 10 is stopped and the clutch 11 is engaged, and the vehicle is put into a motoring state in which the internal combustion engine 10 is driven by the motor 13, and an abnormal diagnosis of the exhaust recirculation unit 25 and the rear O2 sensor 24 is performed.

[0056] As a result, if the water temperature is below a predetermined temperature or the intake air temperature is below a predetermined temperature, a first abnormality diagnosis is performed on the exhaust recirculation device 25 and the rear O2 sensor 24 during deceleration fuel cut, greatly increasing the possibility of completing the abnormality diagnosis early.

[0057] Furthermore, if the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature, and a certain amount of time has not elapsed since the start of the hybrid vehicle 1, a second abnormality diagnosis is performed on the exhaust recirculation device 25 and the rear O2 sensor 24 during deceleration fuel cut, thereby greatly increasing the possibility of completing the abnormality diagnosis early.

[0058] Furthermore, by significantly increasing the likelihood of completing abnormality diagnosis early, it becomes possible to reduce the frequency of switching to motor mode to perform the third abnormality diagnosis during constant-speed driving after the water temperature and intake air temperature have reached a predetermined level, thereby increasing the frequency of EV driving and improving fuel efficiency.

[0059] As a result, the likelihood of completing abnormality diagnosis early can be greatly increased, and the frequency of motoring during constant-speed driving can be reduced, thereby improving fuel efficiency.

[0060] Furthermore, in the hybrid vehicle 1 of this embodiment, the third abnormality diagnosis may be performed by stopping the fuel supply to the internal combustion engine 10 and engaging the clutch 11 to put the vehicle into a motoring state in which the internal combustion engine 10 is driven by the motor 13, provided that the cumulative driving time at a predetermined vehicle speed or higher after the hybrid vehicle 1 has started exceeds a predetermined time and the first and second abnormality diagnoses have not been completed, and then performing an abnormality diagnosis of the exhaust gas recirculation device 25 and the rear O2 sensor 24.

[0061] As a result, if the water temperature is below a predetermined temperature or the intake air temperature is below a predetermined temperature, a first abnormality diagnosis is performed on the exhaust recirculation device 25 and the rear O2 sensor 24 during deceleration fuel cut, greatly increasing the possibility of completing the abnormality diagnosis early.

[0062] Furthermore, if the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature, and the cumulative time spent driving at a predetermined vehicle speed or higher after starting the hybrid vehicle 1 has not exceeded a predetermined time, a second abnormality diagnosis is performed on the exhaust recirculation device 25 and the rear O2 sensor 24 during deceleration fuel cut, thereby greatly increasing the possibility of completing the abnormality diagnosis early.

[0063] Furthermore, by significantly increasing the likelihood of completing the abnormality diagnosis early, the frequency of switching to motor mode to perform the third abnormality diagnosis during constant-speed driving after the water temperature and intake air temperature have reached a predetermined level can be reduced, and the frequency of EV driving can be increased, thereby improving fuel efficiency. In addition, it is possible to accurately determine whether or not an abnormality diagnosis of the exhaust recirculation device 25 and the rear O2 sensor 24 is being performed, thus avoiding unnecessary motor mode activation for abnormality diagnosis.

[0064] As a result, the likelihood of completing abnormality diagnosis early can be greatly increased, and the frequency of motoring during constant-speed driving can be reduced, thereby improving fuel efficiency.

[0065] Furthermore, in the hybrid vehicle 1 of this embodiment, when the abnormality diagnosis unit 32 performs a first abnormality diagnosis, it determines that the vehicle is normal on the condition that it satisfies predetermined diagnostic criteria, and determines that the diagnosis is incomplete on the condition that it does not satisfy the diagnostic criteria. When the second abnormality diagnosis is performed, it determines that the vehicle is normal on the condition that it satisfies the diagnostic criteria, and determines that the vehicle is abnormal on the condition that it does not satisfy the diagnostic criteria.

[0066] This prevents misdiagnosis of an abnormality, as if the first abnormality diagnosis is performed as a preliminary diagnosis before the engine warm-up is complete, the diagnosis will be deemed incomplete if the diagnostic criteria are not met.

[0067] While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims. [Explanation of Symbols]

[0068] 1. Hybrid vehicle 10 Internal combustion engine 11 Clutch 13 Motors 21 Water temperature detection unit 22 Intake air temperature detection unit 24. Rear O2 sensor (on-board device) 25. Exhaust gas recirculation system (on-board device) 30 Control device 31 Drive control unit 32. Department of Abnormal Diagnosis

Claims

1. Internal combustion engines and motors as power sources for vehicles, The system includes a clutch provided between the internal combustion engine and the motor, A control device for a hybrid vehicle that enables EV driving by stopping the internal combustion engine and disengaging the clutch, wherein the vehicle is driven by the motor, A drive control unit that controls the vehicle to perform EV driving while driving at a constant speed, An abnormality diagnosis unit that performs abnormality diagnosis of an in-vehicle device mounted on the aforementioned vehicle, A water temperature detection unit for detecting the water temperature of the cooling water of the internal combustion engine, The system includes an intake air temperature detection unit for detecting the intake air temperature of the intake air supplied to the internal combustion engine, The abnormality diagnosis performed by the aforementioned abnormality diagnosis unit is: A first abnormality diagnosis is performed on the condition that the water temperature is below a predetermined water temperature or the intake air temperature is below a predetermined intake air temperature, and an abnormality diagnosis of the on-board device is performed during deceleration fuel cut, A second abnormality diagnosis is performed during deceleration fuel cut-off, provided that the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature, and A control device for a hybrid vehicle, characterized by including a third abnormality diagnosis, which, provided that a certain amount of time has elapsed since the start of the hybrid vehicle and the first and second abnormality diagnoses have not been completed, stops the fuel supply to the internal combustion engine, engages the clutch, and puts the vehicle into a motoring state in which the internal combustion engine is driven by the motor, and performs an abnormality diagnosis of the on-board device.

2. Internal combustion engines and motors as power sources for vehicles, The system includes a clutch provided between the internal combustion engine and the motor, A control device for a hybrid vehicle that enables EV driving by stopping the internal combustion engine and disengaging the clutch, wherein the vehicle is driven by the motor, A drive control unit that controls the vehicle to perform EV driving while driving at a constant speed, An abnormality diagnosis unit that performs abnormality diagnosis of an in-vehicle device mounted on the aforementioned vehicle, A water temperature detection unit for detecting the water temperature of the cooling water of the internal combustion engine, The system includes an intake air temperature detection unit for detecting the intake air temperature of the intake air supplied to the internal combustion engine, The abnormality diagnosis performed by the aforementioned abnormality diagnosis unit is: A first abnormality diagnosis is performed on the condition that the water temperature is below a predetermined water temperature or the intake air temperature is below a predetermined intake air temperature, and an abnormality diagnosis of the on-board device is performed during deceleration fuel cut, A second abnormality diagnosis is performed during deceleration fuel cut-off, provided that the water temperature is above a predetermined water temperature and the intake air temperature is above a predetermined intake air temperature, and A control device for a hybrid vehicle, characterized by including a third abnormal diagnosis, which, on the condition that the cumulative time of driving at a predetermined vehicle speed or higher after the start of the hybrid vehicle exceeds a predetermined time and the first and second abnormal diagnosis have not been completed, stops the fuel supply to the internal combustion engine, engages the clutch, and puts the vehicle into a motoring state in which the internal combustion engine is driven by the motor, and performs an abnormal diagnosis of the on-board device.

3. The aforementioned abnormality diagnosis unit is When performing the first abnormality diagnosis, the condition is judged as normal if the predetermined diagnostic criteria are met, and judged as incomplete if the diagnostic criteria are not met. The control device for a hybrid vehicle according to claim 1 or 2, characterized in that when performing the second abnormality diagnosis, it determines that the device is normal on the condition that the diagnostic criteria are satisfied, and determines that the device is abnormal on the condition that the diagnostic criteria are not satisfied.

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