CN112172834B

CN112172834B - Control device for hybrid vehicle

Info

Publication number: CN112172834B
Application number: CN202010540220.9A
Authority: CN
Inventors: 安藤大吾; 小林幸男; 浅见良和; 绳田英和
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2019-06-18
Filing date: 2020-06-15
Publication date: 2024-04-19
Anticipated expiration: 2040-06-15
Also published as: JP2020203606A; CN112172834A; JP7147694B2

Abstract

The control device for a hybrid vehicle is provided with an engine control unit that is provided with a diagnostic unit that executes diagnostic processing, and a system control unit that is provided with a stop prohibition unit that executes intermittent stop prohibition processing. The diagnosis unit causes the temporary determination flag to be stored in the nonvolatile memory when it is determined that there is an abnormality by the diagnosis process. On the other hand, the diagnosis unit makes a diagnosis of the intention of abnormality when it is determined that abnormality is present by the diagnosis process in a state in which the temporary determination flag is stored in the nonvolatile memory, and clears the temporary determination flag from the nonvolatile memory. When the temporary determination flag is stored in the nonvolatile memory, the stop prohibition unit executes the intermittent stop prohibition process.

Description

Control device for hybrid vehicle

Technical Field

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

Background

Japanese patent laying-open No. 2006-266193 discloses a hybrid vehicle provided with an engine and a motor. The hybrid vehicle is capable of stopping the engine and running with the motor, and executing intermittent stop control for automatically stopping and restarting the engine.

Disclosure of Invention

When the engine is stopped by the intermittent stop control, it is impossible to diagnose whether or not an abnormality has occurred in an abnormality that cannot be detected if the engine is not running.

Hereinafter, means for solving the above problems and their operational effects are described. A control device for a hybrid vehicle for solving the above-described problems is applied to a hybrid vehicle provided with an engine and a motor as driving force sources, and the control device executes intermittent stop control for automatically stopping and restarting an operation of the engine, and includes: a diagnostic unit that performs a diagnostic process for confirming whether or not an abnormality is present in the engine when the engine is running; and a stop prohibition portion that executes an intermittent stop prohibition process that prohibits stopping of the operation of the engine by the intermittent stop control. In the control device, the diagnosis unit may store the temporary determination flag in the nonvolatile memory when the temporary determination flag is determined to be abnormal by the diagnosis process in a state in which the temporary determination flag is not stored in the nonvolatile memory, and may make a diagnosis of the intention of the abnormality when the temporary determination flag is determined to be abnormal by the diagnosis process in a state in which the temporary determination flag is stored in the nonvolatile memory, and may clear the temporary determination flag from the nonvolatile memory, the temporary determination flag being information indicating that the abnormality may occur. In the control device, the stop prohibition unit executes the intermittent stop prohibition processing when the temporary determination flag is stored in the nonvolatile memory.

According to the above configuration, even if the system main switch is turned off and power supply is stopped, the temporary determination flag can be stored in the nonvolatile memory that is kept stored. Therefore, even if the system main switch of the hybrid vehicle is turned off before the diagnosis of the abnormality is made, it is possible to recognize that the system main switch of the hybrid vehicle is in the middle of the diagnosis based ON the temporary determination flag stored in the nonvolatile memory when the system main switch is turned ON (ON) next time.

When the temporary determination flag is stored, the stop prohibition unit prohibits stopping the engine by the intermittent stop control. Therefore, even when the system main switch is turned off during diagnosis, when the system main switch is turned on next time, the engine operation is immediately prohibited from being stopped by the intermittent stop control when the engine operation is started, and the engine operation is continued. Therefore, the opportunity for execution of the diagnostic process increases, and the diagnosis can be completed promptly, as compared with the case where stopping the operation of the engine by the intermittent stop control is not prohibited.

In one aspect of the control device for a hybrid vehicle, the stop prohibition portion may cancel prohibition of stopping the engine by the temporary determination flag stored when a period in which the system main switch of the vehicle is turned on is set as one stroke and the stroke in which stopping of the engine by the intermittent stop control is prohibited by the temporary determination flag stored continues for a predetermined number of times.

When stopping the operation of the engine by the intermittent stop control is prohibited, the operation of the engine may continue, and thus the fuel consumption may increase. That is, the effect of suppressing the fuel consumption amount that should be obtained by the intermittent stop control cannot be obtained. In contrast, according to the above configuration, it is possible to suppress the continuation of the travel in which the stop of the engine is prohibited more than the predetermined number of times by storing the temporary determination flag. Therefore, it is possible to achieve a compromise between ensuring the execution opportunity of the diagnosis and suppressing the fuel consumption amount, and to suppress an excessive increase in the fuel consumption amount.

Drawings

Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and in which:

Fig. 1 is a schematic diagram showing a relationship between a control device and a hybrid vehicle.

Fig. 2 is a schematic diagram showing the configuration of an engine in a hybrid vehicle.

Fig. 3 is a schematic diagram showing a relationship between an engine control unit and an oil pump.

Fig. 4 is a schematic diagram of an engine control unit and a circulation system of cooling water in the engine.

Fig. 5 is a schematic diagram showing a relation between a crank position sensor and a sensor plate.

Fig. 6 is a timing chart showing waveforms of crank angle signals output from the crank position sensor.

Fig. 7 is a schematic diagram showing a relationship between the cam position sensor on the intake side and the timing rotor.

Fig. 8 is a timing chart showing waveforms of intake side cam angle signals output from the intake side cam position sensor.

Fig. 9 is a timing chart showing the relationship among the crank angle signal, the cam angle signal, and the crank count.

Fig. 10 is a flowchart showing a flow of processing in the provisional determination routine.

Fig. 11 is a flowchart showing a flow of processing in the true determination routine.

Fig. 12 is a flowchart showing a flow of intermittent stop prohibition processing accompanied by the diagnosis processing.

Fig. 13 is a flowchart showing a flow of a process of canceling intermittent stop prohibition accompanied with diagnostic processing.

Fig. 14 is a flowchart showing a flow of processing for calculating a vehicle speed threshold value.

Fig. 15 is a flowchart showing a flow of the intermittent stop prohibition process based on the vehicle speed.

Fig. 16 is a flowchart showing a flow of processing executed at the time of startup in a state where the cam position sensor has failed.

Fig. 17 is a flowchart showing a flow of processing executed during operation in a state where the cam position sensor is out of order.

Fig. 18 is a schematic diagram showing a relationship between a control device and a single motor hybrid vehicle as a modification.

Fig. 19 is a flowchart showing a flow of processing executed by the control device of the operation period modification in the state where the cam position sensor is in failure.

Detailed Description

An embodiment of a control device for a hybrid vehicle will be described below with reference to fig. 1 to 17. As shown in fig. 1, the hybrid vehicle 10 includes an engine 50. The hybrid vehicle 10 further includes a battery 30 that stores electric power. Further, the hybrid vehicle 10 includes a1 st motor generator 11 and a2 nd motor generator 12. These 1 st motor generator 11 and 2 nd motor generator 12 are motors that generate driving force based on power supply from the battery 30, and also function as generators that receive external power to generate electric power charged in the battery 30.

Further, the hybrid vehicle 10 is provided with a planetary gear mechanism 13 having three rotating elements, that is, a sun gear 14, a carrier 15, and a ring gear 16. A crankshaft 59 as an output shaft of the engine 50 is coupled to the carrier 15 of the planetary gear mechanism 13, and the 1 st motor generator 11 is coupled to the sun gear 14 of the planetary gear mechanism 13. Further, a counter DRIVE GEAR (counter DRIVE GEAR) 17 is integrally provided to the ring gear 16 of the planetary gear mechanism 13. A counter DRIVEN GEAR (counter DRIVEN GEAR) 18 is meshed with the counter drive gear 17. The 2 nd motor generator 12 is coupled to a reduction gear 19 meshed with the counter driven gear 18.

The final drive gear (FINAL DRIVE GEAR) 20 is connected to the counter driven gear 18 so as to be rotatable integrally therewith. A final driven gear (FINAL DRIVEN GEAR 2) 21 is engaged with the final drive gear 20. A drive shaft 24 of the wheel 23 is connected to the final driven gear 21 via a differential mechanism 22.

The control device 400 that controls the hybrid vehicle 10 is configured by a system control unit 100, a power control unit 200, and an engine control unit 300.

The 1 st motor generator 11 and the 2 nd motor generator 12 are connected to the battery 30 via a power control unit 200 connected to the system control unit 100. The power control unit 200 includes a control unit, an inverter, and a converter, and adjusts the amount of power supplied from the battery 30 to the 1 st motor generator 11 and the 2 nd motor generator 12, and the amount of charge from the 1 st motor generator 11 and the 2 nd motor generator 12 to the battery 30, based on a command from the system control unit 100. Further, the hybrid vehicle 10 is provided with a connector 31 connectable to an external power source 40. Therefore, the battery 30 can also be charged with the electric power supplied from the external power source 40. That is, the hybrid vehicle 10 is a plug-in hybrid vehicle.

The engine control unit 300 that controls the engine 50 is also connected to the system control unit 100. The engine control unit 300 controls the engine 50 based on instructions from the system control unit 100.

As shown in fig. 2, the engine 50 has an intake passage 51 through which intake air introduced into the combustion chamber 55 flows, and an exhaust passage 60 through which exhaust gas discharged from the combustion chamber 55 flows. The engine 50 is provided with a fuel injection valve 54 that injects fuel supplied from a fuel tank 70, and a spark plug 58 that ignites a mixture of fuel and air injected by the fuel injection valve 54 by spark discharge.

An air cleaner 52, an air flow meter 88, a throttle valve 53, an intake pressure sensor 89, and a fuel injection valve 54 are provided in the intake passage 51 in this order from the upstream side. The air cleaner 52 traps dust and the like in the atmosphere sucked into the intake passage 51. The airflow meter 88 detects the intake air amount as the amount of intake air. Throttle valve 53 is driven by a motor as an electric actuator. In the engine 50, the area of the flow path of the flowing intake air is increased or decreased by changing the opening of the throttle valve 53, thereby adjusting the intake air amount. The intake pressure sensor 89 detects an intake pressure, which is a pressure in a portion of the intake passage 51 downstream of the throttle valve 53. The fuel injection valve 54 injects fuel into the intake air to form a mixture that is combusted in the combustion chamber 55.

A fuel pump 71 is disposed in the fuel tank 70. The fuel pump 71 is driven by a motor. The fuel pumped up by the fuel pump 71 is supplied to the fuel injection valve 54 through the fuel supply passage 73 by the filter 72. The fuel supply passage 73 is provided with a fuel pressure sensor 87 that detects the pressure of the fuel.

From a portion of the fuel supply passage 73 in the fuel tank 70 downstream of the filter 72, a return passage 75 for returning the fuel pumped up by the fuel pump 71 to the fuel tank 70 is branched. An electric relief valve (RELIEF VALVE) 74 is provided in the middle of the return passage 75. The electric relief valve 74 is opened and closed by an electric actuator. When the electric relief valve 74 is opened, the fuel in the fuel supply passage 73 is discharged into the fuel tank 70 through the return passage 75.

As shown in fig. 2, a spark plug 58 for igniting the mixture by an electric spark is provided in the combustion chamber 55. The ignition plug 58 is provided with an igniter 57. The igniter 57 generates the high voltage required to form the spark.

An air-fuel ratio sensor 83, a1 st three-way catalyst 61, an oxygen sensor 84, and a2 nd three-way catalyst 62 are provided in the exhaust passage 60 in this order from the upstream side. The air-fuel ratio sensor 83 detects the oxygen concentration of the exhaust gas discharged from the combustion chamber 55 and the air-fuel ratio of the mixture burned in the combustion chamber 55. The 1 st three-way catalyst 61 and the 2 nd three-way catalyst 62 purify the exhaust gas. The oxygen sensor 84 outputs a signal corresponding to the oxygen concentration of the exhaust gas after passing through the 1 st three-way catalyst 61.

The engine 50 is provided with an intake-side valve timing changing mechanism 56 that changes the opening/closing timing of the intake valve 66, and an exhaust-side valve timing changing mechanism 56 that changes the opening/closing timing of the exhaust valve 67, the intake valve 66 shutting off the intake passage 51 from the combustion chamber 55, and the exhaust valve 67 shutting off the exhaust passage 60 from the combustion chamber. Any of the valve timing changing mechanisms 56 is driven by an electric motor, and changes the rotational phase of the camshaft 91 corresponding to the rotational phase of the crankshaft 59.

In addition, an exhaust gas recirculation system that recirculates a part of the exhaust gas flowing through the exhaust passage 60 to the intake air flowing through the intake passage 51 is provided in the engine 50. The exhaust gas recirculation system has an EGR passage 64 that connects the exhaust passage 60 with the intake passage 51. The EGR passage 64 connects a portion of the exhaust passage 60 downstream of the 1 st three-way catalyst 61 to a portion of the intake passage 51 downstream of the throttle valve 53. An EGR cooler 63 for cooling the gas recirculated from the exhaust passage 60 to the intake passage 51 and an EGR valve 65 for adjusting the amount of the recirculated gas are disposed in the EGR passage 64. The EGR valve 65 is driven by an electric motor.

As shown in fig. 3, an oil pump 170 for circulating oil (oil) in each portion of the engine 50 is provided in the engine 50. Further, the oil pump 170 is driven by the power of the crankshaft 59.

The oil pump 170 is a variable capacity type oil pump capable of changing the discharge amount per one revolution. In the oil pump 170, the discharge amount per one revolution varies according to the control oil pressure controlled by the oil control valve 171. The engine control unit 300 controls the discharge amount of the oil discharged from the oil pump 170 by controlling the oil control valve 171, and controls the oil pressure of the oil circulating through each portion of the engine 50.

The oil pump 170 pumps up the oil stored in the oil pan 173 via the filter 174. The pumped oil is supplied to each part of the engine 50 through the oil supply passage 175. An oil return passage 176 branches off from the oil supply passage 175. The oil return passage 176 is connected to the oil control valve 171. The oil return passage 176 returns a part of the oil discharged from the oil pump 170 to the oil control valve 171.

The oil control valve 171 is connected to a discharge passage 178 and a discharge passage 179 connected to the oil pan 173, and the discharge passage 178 is connected to a control oil chamber for controlling the oil pressure for changing the discharge amount of the oil pump 170. The oil control valve 171 drives a spool valve (spool valve) incorporated therein by an electric actuator, and supplies oil returned through an oil return passage 176 to a control oil chamber of the oil pump 170, thereby increasing a control oil pressure in the control oil chamber. Further, by driving the spool valve, the oil control valve 171 discharges the oil in the control oil chamber to the oil pan 173 through the discharge passage 179, thereby reducing the control oil pressure in the control oil chamber. The oil control valve 171 can also close the discharge passage 178 and the discharge passage 179 by a spool valve to maintain the control oil pressure in the control oil chamber.

The engine control unit 300 controls the oil control valve 171 based on the rotational speed of the crankshaft 59 correlated with the rotational speed of the oil pump 170 and the value of the oil pressure detected by the oil pressure sensor 93, and performs feedback control of the oil pressure of the oil supplied to each portion of the engine 50. When the required oil pressure is low, the discharge amount of oil per one revolution is reduced, and the energy consumption associated with the driving of the oil pump 170 is suppressed. The required oil pressure is calculated by the engine control unit 300 based on the operating state of the engine 50, the operating conditions of the respective devices that are required parts for oil, and the like.

As shown in fig. 4, a water pump 180 is provided in the engine 50, and a cooling system for circulating cooling water is provided in a heat dissipation circuit including a radiator 181.

The water pump 180 is provided in the middle of the introduction passage 184, and the introduction passage 184 introduces cooling water into the water jacket in the engine 50. The cooling water discharged from the water pump 180 is discharged to the discharge passage 185 through the water jacket in the engine 50. The discharge passage 185 is connected to an inlet of the radiator 181. An intake passage 186 connected to a thermostat (thermostat) 183 is connected to an outlet of the radiator 181.

The radiator 181 is provided with a fan 182, and air sucked by the fan 182 passes through the radiator 181, thereby promoting heat exchange between cooling water flowing in the radiator 181 and the air. By this, heat of the cooling water is radiated by passing through the radiator 181, and the temperature of the cooling water is lowered.

The cooling water passing through the radiator 181 flows into the introduction passage 184 through the suction passage 186 and the thermostat 183 (thermostat), and is sucked by the water pump 180. A bypass passage 187 branching from the discharge passage 185 is also connected to the thermostat 183. The thermostat 183 operates according to the temperature of the cooling water introduced through the bypass passage 187.

Specifically, when the temperature of the cooling water introduced through the bypass passage 187, that is, the temperature of the cooling water discharged from the water jacket of the engine 50 is lower than the warm-up determination temperature, the thermostat 183 closes the portion to which the intake passage 186 is connected, and communicates the bypass passage 187 with the introduction passage 184. The warm-up determination temperature is a temperature at which warm-up of the engine 50 is completed, for example, a value of about 80 ℃ when the temperature of the cooling water is equal to or higher than the warm-up determination temperature.

When the portion of the thermostat 183 to which the suction passage 186 is connected is closed in this way, the flow of cooling water passing through the radiator 181 does not occur. As a result, the entire amount of the cooling water discharged through the discharge passage 185 flows into the introduction passage 184 through the bypass passage 187 and the thermostat 183, and is again introduced into the water jacket of the engine 50. This suppresses heat dissipation from the cooling water, and promotes warm-up of the engine 50.

On the other hand, when the temperature of the cooling water introduced through the bypass passage 187 is equal to or higher than the warm-up determination temperature, the thermostat 183 opens the portion to which the suction passage 186 is connected, and communicates the suction passage 186 with the introduction passage 184. When the portion connected to the suction passage 186 is opened in this way, the flow of cooling water passing through the radiator 181 occurs. As a result, the cooling water discharged through the discharge passage 185 flows into the introduction passage 184 through the intake passage 186 and the thermostat 183 via the radiator 181, and is again introduced into the water jacket of the engine 50. Thereby, heat of the cooling water is released from the radiator 181, and the cooling water having a reduced temperature is introduced into the water jacket. Therefore, overheating of the engine 50 can be suppressed.

As shown in fig. 4, a water temperature sensor 81 is provided near the outlet of the water jacket to detect the temperature of the cooling water heated by passing through the water jacket. For such an engine 50. Is controlled by the engine control unit 300 according to an instruction from the system control unit 100. Detection signals of various sensors that detect the operation state of the engine 50 are input to the engine control unit 300. The sensors that input detection signals to the engine control unit 300 also include an air flow meter 88, an intake air pressure sensor 89, an air-fuel ratio sensor 83, an oxygen sensor 84, and a fuel pressure sensor 87. In addition, the engine 50 is provided with a crank position sensor 150 that detects a rotation angle of the crank shaft 59, a water temperature sensor 81 that detects a temperature of cooling water of the engine 50, and an exhaust gas temperature sensor 82 that detects a temperature of exhaust gas flowing through the exhaust passage 60 and introduced into the 1 st three-way catalyst 61. The engine 50 is further provided with a knock sensor 90 that detects the occurrence of knocking and a hydraulic pressure sensor 93 that detects the hydraulic pressure. Further, the crank position sensor 150 outputs a crank angle signal corresponding to a change in the rotational phase of the crankshaft 59.

The engine 50 is further provided with two cam position sensors 160, i.e., an intake-side cam position sensor 160 that detects a rotational phase of the intake-side cam shaft 91 that opens and closes the intake valve 66, and an exhaust-side cam position sensor 160 that detects a rotational phase of the exhaust-side cam shaft 91 that opens and closes the exhaust valve 67. The cam position sensor 160 outputs a cam angle signal corresponding to a change in rotational phase of the cam shaft 91 of the engine 50.

The detection signals of these sensors are input to the engine control unit 300. Engine control unit 300 calculates the engine rotational speed as the rotational speed of crankshaft 59 based on the detection signal of the rotational angle of crankshaft 59 input from crank position sensor 150.

As shown in fig. 1, an accelerator position sensor 85 that detects an operation amount of an accelerator and a vehicle speed sensor 86 that detects a vehicle speed are connected to the system control unit 100. The detection signal of the accelerator position sensor 85 and the detection signal of the vehicle speed sensor 86 are input to the system control unit 100. A system main switch 120 is also connected to the system control unit 100.

In addition, the current, voltage, and temperature of the battery 30 are input to the power control unit 200. Based on these current, voltage, and temperature, power control section 200 calculates a state of charge index value SOC, which is a ratio of the remaining charge amount of battery 30 to the charge capacity.

The engine control unit 300 and the power control unit 200 are connected to the system control unit 100, respectively. The system control unit 100, the power control unit 200, and the engine control unit 300 exchange and share information based on the detection signal input from the sensor and/or the calculated information, respectively.

Based on these pieces of information, the system control unit 100 outputs a command to the engine control unit 300, and the engine 50 is controlled by the engine control unit 300. Based on these pieces of information, system control section 100 outputs a command to power control section 200, and controls 1 st motor generator 11 and 2 nd motor generator 12 and controls charging of battery 30 by power control section 200. In this way, the system control unit 100 controls the hybrid vehicle 10 by outputting instructions to the power control unit 200 and the engine control unit 300.

Next, control of the hybrid vehicle 10 by the control device 400 including the system control unit 100, the power control unit 200, and the engine control unit 300 will be described in detail.

The system control unit 100 calculates a required output, which is a required value of the output of the hybrid vehicle 10, based on the operation amount of the accelerator and the vehicle speed. The system control unit 100 determines torque distributions of the engine 50, the 1 st motor generator 11, and the 2 nd motor generator 12 based on the requested output and/or the state of charge index value SOC of the battery 30, and controls the output of the engine 50, and traction (powering) and regeneration of the 1 st motor generator 11, and the 2 nd motor generator 12. Further, the system control unit 100 switches the running mode of the hybrid vehicle 10 according to the magnitude of the state of charge index value SOC.

The system control unit 100 selects the EV running mode, which is the following mode, when the state of charge index value SOC exceeds a certain level and the remaining charge amount of the battery 30 has a sufficient margin: the engine 50 is deactivated, and the vehicle runs using the driving force generated by the 2 nd motor generator 12 and/or the driving force generated by the 1 st motor generator 11.

On the other hand, when the state of charge index value SOC becomes equal to or lower than a certain level, the system control unit 100 selects the HV travel mode, which is the following mode: the running is performed using the engine 50 in addition to the 1 st motor generator 11 and the 2 nd motor generator 12.

Even when the state of charge index value SOC exceeds a certain level, the system control unit 100 selects the HV travel mode as follows.

When the vehicle speed exceeds the upper limit vehicle speed of the EV running mode.

When a large output is required instantaneously, such as when a large accelerator operation amount is rapidly accelerated.

When the engine 50 needs to be started. When the HV travel mode is selected, the system control unit 100 causes the 1 st motor generator 11 to function as a starter motor when the engine 50 is started. Specifically, the system control unit 100 rotates the sun gear 14 by the 1 st motor generator 11, thereby rotating the crankshaft 59 to start the engine 50.

When the HV travel mode is selected, the system control unit 100 switches the control at the time of parking according to the magnitude of the state of charge index value SOC. Specifically, when the state of charge index value SOC is equal to or greater than the threshold value, the system control unit 100 stops the operation of the engine 50, and does not drive the 1 st motor generator 11 and the 2 nd motor generator 12. That is, the system control unit 100 stops the operation of the engine 50 at the time of stopping the vehicle to suppress the idling operation. When the state of charge index value SOC of the battery 30 is smaller than the threshold value, the system control unit 100 operates the engine 50, and drives the 1 st motor generator 11 by using the output of the engine 50, thereby causing the 1 st motor generator 11 to function as a generator.

When the HV travel mode is selected, the system control unit 100 switches control according to the state of charge index value SOC during travel. When the state of charge index value SOC of the battery 30 is equal to or greater than the threshold value at the time of starting and at the time of light-load running, the system control unit 100 starts and runs the hybrid vehicle 10 using only the driving force of the 2 nd motor generator 12. In this case, the engine 50 is stopped, and electric power generation by the 1 st motor generator 11 is also performed. On the other hand, when the state of charge index value SOC of the battery 30 is smaller than the threshold value at the time of starting and at the time of light-load running, the system control unit 100 starts the engine 50, generates electric power by the 1 st motor generator 11, and charges the battery 30 with the generated electric power. At this time, the hybrid vehicle 10 runs using a part of the driving force of the engine 50 and the driving force of the 2 nd motor generator 12. In steady-state running, when the state of charge index value SOC of the battery 30 is equal to or greater than the threshold value, the system control unit 100 operates the engine 50 in a state where the operation efficiency is high, and the hybrid vehicle 10 is caused to run mainly using the output of the engine 50. At this time, the power of the engine 50 is divided into the wheel 23 side and the 1 st motor generator 11 side via the planetary gear mechanism 13. Thus, the hybrid vehicle 10 travels while generating electric power by the 1 st motor generator 11. The system control unit 100 drives the 2 nd motor generator 12 using electric power generated by the power generation, and assists the power of the engine 50 using the power of the 2 nd motor generator 12. On the other hand, in the case where the state of charge index value SOC of the battery 30 is smaller than the threshold value during steady-state running, the system control unit 100 increases the engine speed, uses the electric power generated by the 1 st motor generator 11 for driving the 2 nd motor generator 12, and charges the remaining electric power to the battery 30. Further, at the time of acceleration, the system control unit 100 increases the engine speed, and uses the electric power generated by the 1 st motor generator 11 for driving the 2 nd motor generator 12, and accelerates the hybrid vehicle 10 by using the power of the engine 50 and the power of the 2 nd motor generator 12. The system control unit 100 stops the operation of the engine 50 at the time of deceleration. The system control unit 100 causes the 2 nd motor generator 12 to function as a generator, and charges the battery 30 with electric power generated by the generation of electric power. In the hybrid vehicle 10, the resistance generated by such power generation is used as a brake. The power generation control at the time of such deceleration is referred to as regeneration control.

In this way, the system control unit 100 naturally stops the engine 50 when the EV running mode is selected, and stops the engine 50 according to the situation when the HV running mode is selected. That is, the system control unit 100 executes intermittent stop control that automatically stops and restarts the engine 50 according to the situation.

As shown in fig. 2, engine control unit 300 includes a count calculating unit 302, and count calculating unit 302 calculates a crank count indicating a crank angle, which is a rotational phase of crankshaft 59. The count calculating unit 302 calculates a crank count based on the crank angle signal, the intake side cam angle signal, and the exhaust side cam angle signal. Engine control unit 300 controls timing of fuel injection and ignition for each cylinder and also controls valve timing changing mechanism 56 with reference to the crank count calculated by count calculating unit 302.

Specifically, engine control unit 300 calculates a target fuel injection amount, which is a control target value for the fuel injection amount, based on the accelerator operation amount, the vehicle speed, the intake air amount, the engine speed, the engine load factor, and the like. Further, the engine load factor is the ratio of the inflow air amount per combustion cycle of one cylinder to the reference inflow air amount. Here, the reference intake air amount is an intake air amount per combustion cycle of one cylinder when the opening degree of the throttle valve 53 is maximized, and is determined based on the engine speed. Engine control unit 300 calculates the target fuel injection amount such that the air-fuel ratio becomes substantially the stoichiometric air-fuel ratio. Then, a control target value concerning the fuel injection timing and the fuel injection time is calculated. The fuel injection valve 54 is driven to open in accordance with these control target values. Thereby, an amount of fuel commensurate with the operating state of the engine 50 is injected and supplied to the combustion chamber 55.

Engine control unit 300 calculates an ignition timing, which is a timing of spark discharge by spark plug 58, to operate igniter 57 to ignite the air-fuel mixture. The engine control unit 300 calculates a target value of the phase of the camshaft 91 on the intake side with respect to the crankshaft 59 and a target value of the phase of the camshaft 91 on the exhaust side with respect to the crankshaft 59 based on the engine speed and the engine load factor, and operates the intake side valve timing changing mechanism 56 and the exhaust side valve timing changing mechanism 56. Thus, engine control unit 300 controls the opening and closing timing of intake valve 66 and the opening and closing timing of exhaust valve 67. For example, engine control unit 300 controls valve overlap, which is a period during which both exhaust valve 67 and intake valve 66 are open.

Next, the crank position sensor 150 and the cam position sensor 160 will be described in detail, and a method of calculating the crank count will be described. First, the crank position sensor 150 will be described with reference to fig. 5 and 6. Fig. 5 shows a relationship between a crank position sensor 150 and a sensor plate 151 attached to a crankshaft 59. Further, the timing chart of fig. 6 shows waveforms of crank angle signals output by the crank position sensor 150.

As shown in fig. 5, a disk-shaped sensor plate 151 is attached to the crankshaft 59. 34 signal teeth 152 each having a width of 5 ° are arranged at an angular interval of 5 ° on the peripheral edge of the sensor plate 151. Therefore, as shown on the right side of fig. 5, a single-site tooth-missing portion 153 is formed in the sensor plate 151, and the tooth-missing portion 153 makes the interval between adjacent signal teeth 152 25 ° in angle, and two signal teeth 152 are missing compared with the other portions.

As shown in fig. 5, the crank position sensor 150 is disposed toward the peripheral edge portion of the sensor plate 151 so as to oppose the signal teeth 152 of the sensor plate 151. The crank position sensor 150 is a magneto-resistive element type sensor including a sensor circuit having a magnet and a magneto-resistive element built therein. When the sensor plate 151 rotates with the rotation of the crankshaft 59, the signal teeth 152 of the sensor plate 151 come close to and separate from the crankshaft position sensor 150. As a result, the direction of the magnetic field of the magnetoresistive element in the crank position sensor 150 changes, and the internal resistance of the magnetoresistive element changes. The sensor circuit compares a magnitude relation between a waveform obtained by converting the resistance value change into a voltage and a threshold value, and shapes the waveform into a rectangular wave based on a Lo signal (low level signal) which is a1 st signal and a Hi signal (high level signal) which is a 2 nd signal, and outputs the rectangular wave as a crank angle signal.

Specifically, as shown in fig. 6, the crank position sensor 150 outputs a Lo signal when facing the signal teeth 152, and outputs a Hi signal when facing the gap portions between the signal teeth 152. Therefore, when the Hi signal corresponding to the tooth missing portion 153 is detected, the Lo signal corresponding to the signal tooth 152 is detected thereafter. Then, the Lo signal corresponding to the signal tooth 152 is detected every 10 ° CA since then. When 34 Lo signals are detected in this way, hi signals corresponding to the tooth missing portions 153 are detected again. Therefore, the rotation angle until the Lo signal corresponding to the next signal tooth 152 sandwiching the Hi signal corresponding to the tooth missing portion 153 is detected is 30 ° CA as the crank angle.

As shown in fig. 6, the interval from when the Lo signal corresponding to the signal tooth 152 is detected next to the Hi signal corresponding to the tooth missing portion 153 to when the Lo signal is detected next to the Hi signal corresponding to the tooth missing portion 153 is 360 ° CA as the crank angle.

The count calculating unit 302 calculates a crank count by counting edges that change from the Hi signal to the Lo signal. Further, based on detection of the Hi signal corresponding to the missing tooth portion 153 having a longer interval than the interval of the other Hi signals, the rotation phase of the crankshaft 59 is detected as the rotation phase corresponding to the missing tooth portion 153.

Next, the cam position sensor 160 will be described with reference to fig. 7. The intake-side cam position sensor 160 and the exhaust-side cam position sensor 160 are both magnetoresistive element type sensors similar to the crank position sensor 150. Since the intake side cam position sensor 160 and the exhaust side cam position sensor 160 are different from each other only in the detected object, the intake side cam angle signal detected by the intake side cam position sensor 160 will be described in detail.

Fig. 7 shows a relationship between the intake cam position sensor 160 and the timing rotor 161 of the camshaft 91 attached to the intake, and the timing chart of fig. 8 shows waveforms of the intake cam angle signal output from the intake cam position sensor 160.

As shown in fig. 7, the timing rotor 161 is provided with a large protrusion 162, a middle protrusion 163, and a small protrusion 164 as 3 protrusions having different sizes from each other in the circumferential direction.

The largest large protrusion 162 is formed to spread over 90 ° as an angle in the circumferential direction of the timing rotor 161. In contrast, the smallest small protrusion 164 is formed to spread over 30 ° as an angle, and the middle protrusion 163 smaller than the large protrusion 162 and larger than the small protrusion 164 is formed to spread over 60 °.

As shown in fig. 7, in the timing rotor 161, large protrusions 162, medium protrusions 163, and small protrusions 164 are arranged with a predetermined interval therebetween. Specifically, the large protrusion 162 and the medium protrusion 163 are disposed at an interval of 60 ° in angle, and the medium protrusion 163 and the small protrusion 164 are disposed at an interval of 90 ° in angle. The large protrusion 162 and the small protrusion 164 are disposed at intervals of 30 ° in angle.

As shown in fig. 7, the cam position sensor 160 is disposed toward the peripheral edge portion of the timing rotor 161 so as to face the large protrusion 162, the middle protrusion 163, and the small protrusion 164 in association with the rotation of the timing rotor 161. The cam position sensor 160 outputs the Lo signal and the Hi signal in the same manner as the crank position sensor 150.

Specifically, as shown in fig. 8, the cam position sensor 160 outputs a Lo signal when facing the large protrusion 162, the middle protrusion 163, and the small protrusion 164, and outputs a Hi signal when facing the space between the protrusions. The cam shaft 91 rotates one revolution during two revolutions of the crankshaft 59. Therefore, the changes in the intake side cam angle signal and the exhaust side cam angle signal are repeatedly changed at a constant rate at 720 ° CA as the crank angle.

As shown in fig. 8, after outputting the Lo signal that continues throughout 180 ° CA corresponding to the large protrusion 162, the Hi signal that continues throughout 60 ° CA is output, and thereafter the Lo signal that continues throughout 60 ° CA corresponding to the small protrusion 164 is output. Then, a Hi signal that continues throughout 180 ° CA is output, and then a Lo signal that continues throughout 120 ° CA corresponding to the middle projection 163 is output. Then, after the Hi signal continuing throughout 120 ° CA is finally output, the Lo signal continuing throughout 180 ° CA corresponding to the large protrusion 162 is output again.

In this way, the intake side cam angle signal periodically changes in a certain change pattern, and therefore, by recognizing the change pattern of the cam angle signal, the engine control unit 300 can detect which rotational phase the camshaft 91 is in. For example, when the Lo signal of a length equivalent to 60 ° CA is output and then switched to the Hi signal, the engine control unit 300 can detect that the rotation phase of the small protrusion 164 immediately before and after the cam position sensor 160 is passed.

In the engine 50, a timing rotor 161 of the same shape is also mounted on the exhaust side camshaft 91. Accordingly, the exhaust side cam angle signal detected by the exhaust side cam position sensor 160 also periodically changes in the same change pattern as the intake side cam angle signal shown in fig. 8. Therefore, by recognizing the change pattern of the exhaust side cam angle signal output from the exhaust side cam position sensor 160, the engine control unit 300 can detect which rotational phase the exhaust side camshaft 91 is located in.

The timing rotor 161 of the camshaft 91 attached to the exhaust side is attached to the timing rotor 161 of the camshaft 91 attached to the intake side with a phase offset. Specifically, the timing rotor 161 of the camshaft 91 attached to the exhaust side is attached with a phase shifted to the advance side by 30 ° from the timing rotor 161 of the camshaft 91 attached to the intake side.

Thus, as shown in fig. 9, the change pattern of the intake side cam angle signal changes with a delay of 60 ° CA in the crank angle with respect to the change pattern of the exhaust side cam angle signal.

Fig. 9 is a timing chart showing a relationship between a crank angle signal and a crank count, and a relationship between a crank count and a cam angle signal. In fig. 9, only the edge that changes from the Hi signal to the Lo signal is illustrated with respect to the crank angle signal.

As described above, the count calculating unit 302 of the engine control unit 300 calculates the crank count by counting the edges when the crank angle signal output from the crank position sensor 150 changes from the Hi signal to the Lo signal in accordance with the operation of the engine 50. The count calculating unit 302 determines a cylinder based on the crank angle signal, the intake side cam angle signal, and the exhaust side cam angle signal.

Specifically, the count calculating unit 302 counts the edges of the crank angle signal output every 10 ° CA as shown in fig. 9, and increases the crank count (count up) every time 3 edges are counted. That is, the count calculating unit 302 increases the crank count, which is the value of the crank count, for every 30 ° CA. Engine control unit 300 recognizes the current crank angle based on the crank count, and controls the timing of fuel injection and ignition for each cylinder.

The crank count is periodically reset every 720 ° CA. That is, as shown in the center of fig. 9, after increasing to "23" corresponding to 690 ° CA, at the timing of the next increase, the crank count is reset to "0", from where the crank count starts to increase again every 30 ° CA.

When the missing tooth portion 153 passes before the crank position sensor 150, the interval between detected edges becomes 30 ° CA. Then, when the interval of the edges becomes wider, the count calculating unit 302 detects that the missing tooth portion 153 passes before the crank position sensor 150 based on this. Since this missing tooth detection is performed every 360 ° CA, 2 missing tooth detections are performed during 720 ° CA in which the crank count is increased by 1 cycle.

Further, since the crankshaft 59, the intake-side camshaft 91, and the exhaust-side camshaft 91 are connected to each other via a timing chain, a change in the crank count and a change in the cam angle signal have a certain correlation.

That is, during two rotations of the crankshaft 59, the intake-side camshaft 91 and the exhaust-side camshaft 91 rotate one rotation, respectively. Therefore, knowing the crank count enables estimation of the rotational phases of the intake side camshaft 91 and the exhaust side camshaft 91 at that time. Conversely, if the rotational phases of the intake side camshaft 91 and the exhaust side camshaft 91 are known, the crank count can be estimated.

The count calculating unit 302 uses the relationship between the intake side cam angle signal and the exhaust side cam angle signal and the crank count, and the relationship between the missing tooth detection and the crank count to determine the crank angle that becomes the starting point when the crank count starts to be calculated, and also to determine the crank count.

The count calculating unit 302 recognizes the crank angle and recognizes the value of the crank count as the starting point, and starts to increase with the recognized value of the crank count as the starting point. That is, the crank count is not specified during a period when the crank angle is not found and the value of the crank count that becomes the starting point is not found, and is not outputted. After the value of the crank count that becomes the starting point is found, the crank count starts to be increased and output with the found value of the crank count as the starting point.

When the relative phase of the intake camshaft 91 with respect to the crankshaft 59 is changed by the intake valve timing changing mechanism 56, the relative phase of the sensor plate 151 attached to the crankshaft 59 and the timing rotor 161 of the intake camshaft 91 also changes. Therefore, engine control unit 300 grasps the amount of change in the relative phase from the displacement angle, which is the operation amount of valve timing changing mechanism 56 on the intake side, and determines the crank count as the starting point in consideration of the influence caused by the change in the relative phase. The same applies to the change of the relative phase of the exhaust side camshaft 91 by the exhaust side valve timing changing mechanism 56.

In the engine 50, as shown in fig. 9, the crank angle at the time of switching from the Lo signal, which is continuous over 180 ° CA from the intake side cam angle signal, to the Hi signal, which is continuous over 60 ° CA, is set to "0 ° CA". Therefore, as shown by a broken line in fig. 9, the missing tooth detection performed immediately after the Hi signal that continues from the intake cam angle signal over 60 ° CA is switched to the Lo signal becomes a detection indicating that the crank angle is 90 ° CA. On the other hand, the missing tooth detection performed immediately after the Lo signal continued from the intake cam angle signal over 120 ° CA is switched to the Hi signal is a detection indicating that the crank angle is 450 ° CA. In this way, engine control unit 300 uses the relationship between the detection of missing tooth portion 153 and the transition of the intake cam angle signal, determines the crank angle when missing tooth portion 153 is detected, determines the crank count to be the starting point, and starts calculation of the crank count.

In fig. 9, the value of the crank count is shown in a solid line indicating transition of the value of the crank count, and a crank angle corresponding to the value of the crank count is shown in the solid line. Fig. 9 shows a state where both the displacement angle in the intake-side valve timing changing mechanism 56 and the displacement angle in the exhaust-side valve timing changing mechanism 56 are "0".

The control device 400 executes a diagnosis process for confirming whether or not there is an abnormality in various devices provided in the engine 50. Accordingly, as shown in fig. 2 to 4, the control device 400 is provided with a diagnostic unit 301 that executes diagnostic processing in the engine control unit 300.

For example, the diagnostic unit 301 determines that an abnormality has occurred in the fuel system such as the fuel injection valve 54 based on the fact that the value detected by the air-fuel ratio sensor 83 has a large deviation from the target value. The diagnosis unit 301 determines that an abnormality has occurred in the air-fuel ratio sensor 83 based on the fact that the state where the learning value learned by the learning process described later matches the upper limit value continues and the state where the learning value matches the lower limit value continues.

The diagnostic unit 301 also drives the EGR valve 65 to open and close during a fuel cut operation such as deceleration. Then, based on the fact that the pressure detected by the intake pressure sensor 89 does not follow the opening/closing drive change, it is determined that an abnormality has occurred in the EGR valve 65.

The diagnostic process performed by the diagnostic unit 301 includes, for example, the following processes.

The diagnostic unit 301 checks whether or not the relation between the cam angle signal and the crank angle signal changes by an amount corresponding to the driving amount when the valve timing changing mechanism 56 is driven, and determines that an abnormality has occurred in the valve timing changing mechanism 56 based on the fact that the relation does not change by an amount corresponding to the driving amount.

The diagnostic unit 301 determines that an abnormality has occurred in the oil pump 170 based on the fact that the deviation of the required oil pressure from the oil pressure detected by the oil pressure sensor 93 is large.

The diagnostic unit 301 determines that an imbalance is occurring, which is an abnormality in which the inter-cylinder combustion non-uniformity increases, based on the variation in the engine rotational speed. Specifically, the diagnostic unit 301 executes a diagnostic process for determining unbalance on the condition that warm-up is completed. In this diagnosis process, the diagnosis unit 301 obtains the angular velocity of the crankshaft 59 at the time of ignition. For example, the diagnostic unit 301 obtains T30, and T30 is the time required for the crank angle to change by 30 ° CA as the angular velocity. The diagnosis unit 301 determines that an imbalance has occurred based on a case where the angular velocity difference from the angular velocity obtained when ignition is performed in the other cylinder is equal to or greater than a threshold value. The imbalance includes a rich imbalance in which the air-fuel ratio is rich and the angular velocity is large as compared with other cylinders, and a lean imbalance in which the air-fuel ratio is lean and the angular velocity is small as compared with other cylinders. Further, when performing the imbalance diagnosis process, engine control unit 300 delays the ignition timing and increases the intake air amount in order to secure the S/N ratio, which is the ratio of the signal to the noise.

The diagnostic unit 301 determines that there is a misfire that is an abnormality of misfire in the cylinder. Specifically, the diagnostic unit 301 executes the diagnostic process for determining the misfire on the condition that the engine speed is within the range suitable for diagnosis and the engine load is low. In this diagnosis process, the diagnosis unit 301 obtains the angular velocity of the crankshaft 59 at the time of ignition. For example, the diagnostic unit 301 obtains T30, and T30 is the time required for the crank angle to be changed by 30 ° CA as the angular velocity. The diagnostic unit 301 determines that a misfire has occurred based on a case where the angular velocity deviation from the angular velocity obtained when the previous ignition was performed in the same cylinder is equal to or greater than a threshold value.

The engine control unit 300 performs ISC control of feedback-controlling the engine speed to the target idle speed during idle operation of the engine 50. The target idle rotation speed is corrected at the time of start-up, external load correction according to external loads of an auxiliary machine such as an air conditioner mounted on the hybrid vehicle 10 and the 1 st motor generator 11 and the 2 nd motor generator 12, and water temperature correction according to the temperature of the cooling water. The details will be described later, but when a state in which the feedback correction amount in the ISC control is large continues, a learning process of converting the feedback correction amount into a learning value is performed. The diagnostic unit 301 determines that an abnormality has occurred in the ISC control based on the case where the state where the learning value matches the upper limit value continues and the case where the state where the learning value matches the lower limit value continues.

The diagnosis unit 301 determines that an abnormality has occurred in the thermostat 183 based on the fact that the temperature of the cooling water detected by the water temperature sensor 81 is equal to or higher than the abnormality determination temperature that is higher than the warm-up determination temperature.

When the operation state of the engine 50 is stable, such as during steady operation, the diagnostic unit 301 opens and closes the throttle valve 53 to check whether or not the intake air amount detected by the airflow meter 88 varies. The diagnostic unit 301 determines that an abnormality has occurred in the air flow meter 88 based on the fact that the intake air amount detected by the air flow meter 88 does not change.

Further, with these diagnostic processes, when the engine 50 is not operating, it is not possible to determine whether there is an abnormality. Then, as shown in fig. 1, in the control device 400, a stop prohibition portion 101 is provided in the system control unit 100, and the stop prohibition portion 101 executes an intermittent stop prohibition process that prohibits stopping the operation of the engine 50 by intermittent stop control. The stop prohibition unit 101 monitors an intermittent stop prohibition flag, which will be described later, when the system main switch 120 is turned ON, and executes intermittent stop prohibition processing for prohibiting the operation of the engine 50 from being stopped by the intermittent stop control when the intermittent stop prohibition flag is turned ON. In the case of executing the intermittent stop prohibition processing, the system control unit 100 does not stop the engine 50 and keeps the engine 50 running even when there is a request for automatic stop of the engine 50 by the intermittent stop control. That is, stopping the operation of the engine 50 by the intermittent stop control is prohibited, and the engine 50 is kept running.

Next, a relationship between the diagnostic process performed by the diagnostic unit 301 and the intermittent stop prohibition process performed by the stop prohibition unit 101 will be described with reference to fig. 10 to 13. In the control device 400, when the engine 50 is operated and the execution condition of the diagnostic process is satisfied in a state where neither the temporary determination flag nor the real determination flag is stored in the nonvolatile memory 104, the temporary determination routine shown in fig. 10 is executed. The provisional determination routine shown in fig. 10 is executed by the engine control unit 300 by the kind of diagnostic process. In addition, in the case where the diagnosis process does not make a determination that an abnormality has occurred, the diagnosis portion 301 does not execute the diagnosis process for the duration of the operation of the engine 50.

The temporary determination flag is information indicating that an abnormality is likely to occur. As shown in fig. 1, the temporary determination flag is stored in the nonvolatile memory 104 provided in the system control unit 100, and becomes active. The temporary determination flag is not stored in the initial state but is not activated (OFF). The temporary determination flag is set for each type of diagnosis process, and is updated according to the result of the diagnosis process. The nonvolatile memory 104 is a memory capable of holding storage even when the power supply is stopped by turning OFF (OFF) the system main switch 120.

The true determination flag is information indicating that a diagnosis of occurrence of an abnormality has been made by the diagnosis process. The true determination flag is also stored in the nonvolatile memory 104 and becomes active (ON). The true determination flag is not stored in the initial state but is inactive (OFF). The true determination flag is also set for each type of diagnosis process, and is updated according to the result of the diagnosis process.

As shown in fig. 10, when the routine is started, the engine control unit 300 first executes the process of step S100. In the process of step S100, the diagnostic unit 301 of the engine control unit 300 executes a diagnostic process. Then, engine control unit 300 advances the process to step S110. In the process of step S110, engine control unit 300 determines whether or not diagnostic unit 301 has determined that there is an abnormality in the process of step S100.

When the diagnosis unit 301 determines that there is an abnormality in the process of step S110 (yes in step S110), the engine control unit 300 advances the process to step S120. In the process of step S120, the diagnostic unit 301 causes the temporary determination flag to be stored in the nonvolatile memory 104 of the system control unit 100, and causes the temporary determination flag to be activated. Engine control unit 300 then temporarily ends the routine.

On the other hand, when the diagnosis unit 301 does not determine that there is any abnormality (no in step S110) in the process in step S110, the engine control unit 300 does not execute the process in step S120, and the routine is temporarily terminated. That is, in this case, the diagnosis unit 301 does not store the temporary determination flag in the nonvolatile memory 104.

In this way, in the control device 400, if the temporary determination flag and the real determination flag are not activated, the temporary determination flag is stored in the nonvolatile memory 104 on the condition that the diagnosis unit 301 determines that there is an abnormality by the diagnosis process.

As shown in fig. 1, the hybrid vehicle 10 is provided with a warning display unit 110, and the warning display unit 110 displays information indicating occurrence of an abnormality and notifies the occupant of the occurrence of the abnormality. When the temporary determination flag is stored in the nonvolatile memory 104, the system control unit 100 causes the warning display unit 110 to display information indicating that an abnormality has occurred.

In the control device 400, when the engine 50 is operated and the execution condition of the diagnostic process is satisfied in a state where the temporary determination flag is stored in the nonvolatile memory 104, the actual determination routine shown in fig. 11 is executed. The true determination routine shown in fig. 11 is executed by the engine control unit 300 by the kind of diagnostic process.

As shown in fig. 11, when the routine is started, the engine control unit 300 first executes the process of step S200. In the process of step S200, the diagnostic portion 301 of the engine control unit 300 executes a diagnostic process.

In addition, in the case where the diagnostic process concerning the oil pump 170 is performed and in the case where the diagnostic process concerning the valve timing changing mechanism 56 is performed in the process of step S200, the diagnostic process is performed after the release operation is performed before the execution of the diagnostic process. The release operation is an operation of reciprocating the actuator to eliminate the abnormality. In the case of the oil pump 170, the spool valve of the oil control valve 171 is reciprocated as a release operation, so that the foreign matter in the oil control valve 171 is removed. In the case of the valve timing changing mechanism 56, the motor is reciprocated to eliminate the sticking of foreign matter.

When the diagnosis unit 301 executes the diagnosis process by the process of step S200, the engine control unit 300 advances the process to step S210. In the process of step S210, engine control unit 300 determines whether or not diagnostic unit 301 determines that there is an abnormality in the process of step S200.

When the processing in step S210 makes a determination that the diagnostic unit 301 has determined that there is an abnormality (yes in step S210), the engine control unit 300 advances the processing to step S220. In the process of step S220, the diagnostic unit 301 causes the nonvolatile memory 104 of the system control unit 100 to store the true determination flag, and causes the true determination flag to be activated. Further, engine control unit 300 advances the process to step S250. In the process of step S250, the diagnostic unit 301 clears the temporary determination flag stored in the nonvolatile memory 104 of the system control unit 100, and deactivates the temporary determination flag. Engine control unit 300 then temporarily ends the routine.

On the other hand, when the diagnosis unit 301 determines that there is no abnormality in the process of step S210 (step S210: no), the engine control unit 300 advances the process to step S230. Then, in the process of step S230, the diagnostic unit 301 increases the normal count by one. The normal count is stored in the memory of the engine control unit 300. The memory is not a nonvolatile memory, and if the power supply is stopped, the normal count is reset. The normal count is "0" in the initial state. Next, engine control unit 300 advances the process to step S240. Then, in the process of step S240, engine control unit 300 determines whether or not the normal count is "3" or more. When it is determined that the normal count is "3" or more in the process of step S240 (yes in step S240), engine control unit 300 advances the process to step S250. Then, in the process of step S250, the diagnosis unit 301 clears the temporary determination flag stored in the nonvolatile memory 104 of the system control unit 100, and deactivates the temporary determination flag. Engine control unit 300 then temporarily ends the routine.

On the other hand, when it is determined that the normal count is smaller than "3" in the process of step S240 (step S240: no), the engine control unit 300 does not execute the process of step S250, and the routine is temporarily ended.

In this way, in the control device 400, when the diagnosis unit 301 determines that there is an abnormality by the diagnosis process in the state where the temporary determination flag is stored in the nonvolatile memory 104, a diagnosis is made that there is an abnormality, and the real determination flag is stored in the nonvolatile memory 104. At this time, the diagnosis unit 301 clears the temporary determination flag stored in the nonvolatile memory 104.

Even when the temporary determination flag is cleared and the temporary determination flag is not stored in the nonvolatile memory 104, the system control unit 100 causes the warning display unit 110 to continue displaying information indicating that an abnormality has occurred when the real determination flag is stored in the nonvolatile memory 104.

On the other hand, when the temporary determination flag is cleared, the temporary determination flag is not stored in the nonvolatile memory 104, and the real determination flag is not stored in the nonvolatile memory 104, the system control unit 100 stops the display of information indicating that an abnormality has occurred in the warning display unit 110. In this case, the temporary determination flag is cleared, and the display indicating the occurrence of the abnormality is lost. That is, in the control device 400, when the temporary determination flag is activated and the determination that the abnormality has not occurred is continued for 3 times in the state in which the abnormality has not been determined in the diagnosis process, the temporary determination flag is cleared, and the display indicating that the abnormality has occurred is stopped.

Further, the true determination flag is cleared from the nonvolatile memory 104 when the abnormality is eliminated by repair in a repair factory or the like. Therefore, after diagnosis of occurrence of an abnormality is temporarily made by the diagnosis process and the real determination flag is stored in the nonvolatile memory 104, the warning display unit 110 continues to display information indicating occurrence of an abnormality until the real determination flag is cleared by repair or the like.

Fig. 12 is a routine repeatedly executed by the system control unit 100 during the operation of the control device 400 while the system main switch 120 is turned on. As shown in fig. 12, when the routine is started, the system control unit 100 first determines in the process of step S300 whether any of the temporary determination flags set for each type of diagnostic process is activated. That is, the system control unit 100 determines whether any temporary determination flag is stored in the nonvolatile memory 104.

When it is determined that any one of the temporary determination flags is activated in the process of step S300 (yes in step S300), the system control unit 100 advances the process to step S310. Then, the system control unit 100 stores the 1 st intermittent stop prohibition flag in the memory in the process of step S310, and the 1 st intermittent stop prohibition flag sets one of three intermittent stop prohibition flags. Thereby, the 1 st intermittent stop prohibition flag becomes active. In addition, the memory is not a nonvolatile memory, and when the power supply is stopped, the 1 st intermittent stop prohibition flag is deactivated. When the 1 st intermittent stop prohibition flag is thus activated, the system control unit 100 temporarily ends the routine. In the initial state, the 1 st intermittent stop prohibition flag is not stored in the memory but is deactivated.

On the other hand, in the case where it is determined that none of the temporary determination flags is activated in the process of step S300 (step S300: no), the system control unit 100 advances the process to step S320. Further, the system control unit 100 clears the 1 st intermittent stop prohibition flag from the memory in the process of step S320. Thus, the 1 st intermittent stop prohibition flag becomes inactive. When the 1 st intermittent stop prohibition flag is deactivated in this way, the system control unit 100 temporarily ends the routine.

As described above, the stop prohibition portion 101 executes the intermittent stop prohibition process that prohibits the stopping of the operation of the engine 50 by the intermittent stop control when the intermittent stop prohibition flag becomes active. As described with reference to fig. 12, when the temporary determination flag is activated, the system control unit 100 activates the 1 st intermittent stop prohibition flag. That is, in the control device 400, when the temporary determination flag is stored in the nonvolatile memory 104, the stop prohibition unit 101 executes the intermittent stop prohibition process.

Fig. 13 shows a flow of processing of a routine executed by the system control unit 100 until the operation of the control device 400 is stopped when the system main switch 120 is turned off with the 1 st intermittent stop prohibition flag being activated.

As shown in fig. 13, when starting the routine, the system control unit 100 first increases the prohibition continuation count in the process of step S400. The prohibit continuation count is "0" in the initial state, and is incremented one by one every time the process of this step S400 is performed. The inhibit keep-alive count is stored in the non-volatile memory 104.

Next, the system control unit 100 determines in the process of step S410 whether or not the prohibit continuous count is "2" or more. When it is determined in the process of step S410 that the continuous count is "2" or more (yes in step S410), the system control unit 100 advances the process to step S420.

Then, in the process of step S420, the system control unit 100 deactivates the temporary determination flag. That is, the system control unit 100 clears the temporary determination flag stored in the nonvolatile memory 104.

Next, the system control unit 100 deactivates the 1 st intermittent stop prohibition flag in the process of step S430. That is, the system control unit 100 clears the 1 st intermittent stop prohibition flag stored in the nonvolatile memory 104. The system control unit 100 resets the inhibit continuous count in the next processing of step S440. Then, the system control unit 100 ends the routine.

On the other hand, when it is determined that the continuous count is smaller than "2" in the process of step S410 (yes in step S410), the system control unit 100 does not execute the processes of step S420 to step S440, and directly ends the routine.

By executing the routine described with reference to fig. 13, the intermittent stop prohibition processing is limited to two strokes in which the temporary determination flag is activated and continued. That is, when the system main switch 120 is turned off 2 times in the state where the temporary determination flag is activated, the prohibition continuation count is "2", and the temporary determination flag and the 1 st intermittent stop prohibition flag are cleared. When the 1 st intermittent stop prohibition flag is cleared, the stop prohibition portion 101 ends the intermittent stop prohibition process performed by storing the temporary determination flag. In this way, in the control device 400, when the temporary determination flag is stored and the stop of the engine 50 by the intermittent stop control is prohibited for 2 times, the stop prohibition portion 101 releases the prohibition of the stop of the engine 50 by the temporary determination flag stored.

Here, the stroke refers to a period in which the system main switch 120 of the hybrid vehicle 10 is turned on, that is, a period in which the operation of the control device 400 of the hybrid vehicle 10 is continued, as a unit of 1 stroke.

Next, a learning process performed by the control device 400 and an intermittent stop prohibition process associated therewith will be described. The learning process is executed by the engine control unit 300 during the operation of the engine 50 and when the execution condition is satisfied.

For example, engine control unit 300 performs air-fuel ratio main feedback learning, which learns a deviation of the steady-state air-fuel ratio caused by a deviation of the fuel injection amount injected from fuel injection valve 54, as one of learning processes. In this air-fuel ratio main feedback learning, the learning value is updated by calculating a time integration amount of a correction amount of the fuel injection amount in the air-fuel ratio main feedback control using the detection value of the air-fuel ratio sensor 83, and converting the time integration amount into the learning value at a constant ratio for each constant time. In addition, engine control unit 300 performs air-fuel ratio sub-feedback learning as one of learning processes, the air-fuel ratio sub-feedback learning a deviation of the steady-state air-fuel ratio caused by a deviation of the detection value of air-fuel ratio sensor 83. In this air-fuel ratio sub-feedback learning, the learning value is updated by calculating a time integration amount of a correction amount of the fuel injection amount in the air-fuel ratio sub-feedback control using the detection value of the oxygen sensor 84 and converting the time integration amount into the learning value at a constant ratio for each constant time.

The learning process performed by the engine control unit 300 includes, for example, the processes listed below.

The engine control unit 300 executes ISC learning for learning a steady-state deviation of the engine rotational speed in ISC control, which is feedback control of the engine rotational speed in idle operation. In the ISC learning, the time integration amount of the correction amount of the throttle opening degree in the ISC control is calculated, and the time integration amount is converted into a learning value at a constant ratio for each constant time, whereby the learning value is updated.

Engine control unit 300 performs KCS learning in KCS control, which is control of ignition timing for suppressing knocking in engine 50. In KCS learning, when the correction amount of the ignition timing in KCS control becomes equal to or greater than a threshold value, a part of the correction amount is converted into a learning value, thereby updating the learning value.

Engine control unit 300 performs throttle learning that learns a deviation between the intake air amount detected by air flow meter 88 and the intake air amount assumed according to the throttle opening. In the throttle learning, when the corrected amount of the throttle opening in the feedback control of the intake air amount becomes equal to or greater than the threshold value, the learned value is updated by converting a part of the correction amount into the learned value.

Further, each learning value is stored in the nonvolatile memory 104. Therefore, the learned value is stored in the nonvolatile memory 104 even when the system main switch 120 is turned off. Therefore, when learning is completed, it is possible to immediately execute control in which the learned value is reflected when the engine 50 is started next time. Therefore, it is preferable to promptly complete the updating of the learning value.

However, with the learning process described above, when the engine 50 is running and the conditions suitable for executing the respective learning processes are not satisfied, the learning process cannot be executed. Thus, for example, japanese patent laid-open No. 11-107834 discloses the following: stopping the operation of the engine 50 by the intermittent stop control is prohibited until the learning process is completed, thereby causing the learning process to be completed promptly.

However, when stopping the operation of the engine 50 by the intermittent stop control is prohibited, the operation of the engine is continued, and therefore, the fuel consumption increases, and the fuel consumption suppressing effect to be obtained by the intermittent stop control cannot be obtained. There is also a case where it is not necessarily required to prioritize completion of the learning process, and therefore there is room for improvement.

Then, the control device 400 changes the vehicle speed threshold value, which is a threshold value for determining whether to execute the intermittent stop prohibition process, based on the cumulative amount of operation of the engine 50 since the completion of learning of the learning value by the latest learning process, so as to ensure the reconciliation between the update opportunity of the learning value and the fuel consumption suppression amount achieved by executing the intermittent stop control. Accordingly, as shown in fig. 1, the control device 400 is provided with a work load calculation unit 102 that calculates an index value indicating the cumulative work load and a threshold value calculation unit 103 that calculates a vehicle speed threshold value in the system control unit 100.

The change of the condition for executing the intermittent stop prohibition processing according to the cumulative workload will be specifically described with reference to fig. 14 and 15. Moreover, the ease of occurrence of knocking may suddenly change when the fuel property changes due to the supply of oil. Therefore, regarding KCS learning, it is preferable to perform per stroke. Then, in the control device 400, the intermittent stop prohibition process is executed at the time of the initial operation of the engine 50 in each stroke until the KCS learning is completed, so that the KCS learning is completed promptly.

With the routine shown in fig. 14, after the learning process is completed, it is repeatedly executed by the system control unit 100 while the engine 50 is running. Further, the routine is executed by the kind of learning processing.

As shown in fig. 14, when the routine is started, the system control unit 100 first calculates an index value of the cumulative workload in the process of step S500. Here, as the index value of the cumulative workload, the workload calculation unit 102 calculates, for example, the cumulative travel distance of the hybrid vehicle 10 from the completion of learning the learning value by the latest learning process. The longer the cumulative travel distance, the more likely the cumulative workload of the engine 50 becomes. Therefore, by calculating the cumulative travel distance from completion of learning as the index value of the cumulative amount of operation of the engine 50 from completion of learning, the cumulative amount of operation of the engine from completion of learning can be estimated based on the calculated index value.

Next, the system control unit 100 advances the process to step S510. In the process of step S510, the system control unit 100 reads a correction amount in control of the subject to learn the learning value. For example, if the control to be the subject of learning the learning value is the air-fuel ratio main feedback control, the correction amount of the fuel injection amount in the air-fuel ratio main feedback control is read.

Then, in the next step S520, the system control unit 100 calculates a vehicle speed threshold based on the index value of the integrated workload calculated by the workload calculation unit 102 and the read correction amount. In the process of step S520, the threshold value calculating unit 103 of the system control unit 100 calculates a smaller value as the vehicle speed threshold value as the index value of the integrated workload increases. The threshold value calculating unit 103 calculates a smaller value as the vehicle speed threshold value as the read correction amount increases.

When the vehicle speed threshold is thus calculated, the system control unit 100 temporarily ends the routine. The routine shown in fig. 15 is repeatedly executed by the system control unit 100 when the HV travel mode is selected and the calculation of the vehicle speed threshold value relating to a certain learning process is completed.

When this routine is started, the system control unit 100 first compares the minimum vehicle speed threshold value among the calculated vehicle speed threshold values with the vehicle speed detected by the vehicle speed sensor 86 in the process of step S600, and determines whether or not the vehicle speed is equal to or higher than the vehicle speed threshold value.

When it is determined that the vehicle speed is equal to or greater than the vehicle speed threshold in the process of step S600 (yes in step S600), the system control unit 100 advances the process to step S610. Further, in the process of step S610, the system control unit 100 stores a 2 nd intermittent stop prohibition flag, which is one of three intermittent stop prohibition flags, in the memory. Thereby, the 2 nd intermittent stop prohibition flag becomes active. In addition, the memory is not a nonvolatile memory, and when the power supply is stopped, the 2 nd intermittent stop prohibition flag is deactivated. When the 2 nd intermittent stop prohibition flag is thus activated, the system control unit 100 temporarily ends the routine. In the initial state, the 2 nd intermittent stop prohibition flag is not stored in the memory but is deactivated. The 2 nd intermittent stop prohibition flag is set for each type of learning process, and in the process of step S610, the 2 nd intermittent stop prohibition flag is activated, and the 2 nd intermittent stop prohibition flag is a flag for the learning process corresponding to the vehicle speed threshold value compared with the vehicle speed in the process of step S600.

On the other hand, when the process of step S600 determines that the vehicle speed is less than the vehicle speed threshold (step S600: no), the system control unit 100 does not execute the process of step S610, and the routine is terminated once.

As described above, the stop prohibition portion 101 executes the intermittent stop prohibition process that prohibits the stopping of the operation of the engine 50 by the intermittent stop control when the intermittent stop prohibition flag becomes active. As described with reference to fig. 15, when the vehicle speed is equal to or higher than the vehicle speed threshold, the system control unit 100 activates the 2 nd intermittent stop prohibition flag. Further, in the control device 400, the vehicle speed threshold value is reduced as the cumulative workload increases. Further, the larger the correction amount in the control, the smaller the vehicle speed threshold value. Accordingly, in the control device 400, the larger the integrated amount of work is, and the larger the correction amount is, the intermittent stop prohibition processing is executed from the lower vehicle speed. As a result, the chance of executing the intermittent stop prohibition processing increases, and the intermittent stop prohibition processing becomes easy to execute. That is, the control device 400 can increase the execution opportunity of the intermittent stop prohibition processing and ensure the update opportunity of the learning value in accordance with an increase in the necessity of updating the learning value with an increase in the cumulative amount of the engine 50.

Further, when the corresponding learning process is completed and the learning value is updated, the 2 nd intermittent stop prohibition flag is reset to inactive. Next, control related to starting of the engine 50 when the cam position sensor 160 fails will be described with reference to fig. 16 and 17.

As described above, when the engine 50 is started, the missing tooth portion 153 is detected once every time the crankshaft 59 makes one revolution, and the cam angle signal output from the cam position sensor 160 is detected, and the cam position sensor 160 detects the arrival of a specific cam angle of the cam shaft 91 that makes two revolutions during one revolution of the crankshaft 59. Then, it is determined which one of the crank count values corresponds to the crank angle of the crankshaft 59 by two revolutions corresponds to the missing tooth portion 153. Japanese patent laying-open No. 2015-059469 also discloses a control device for an internal combustion engine that generates a crank count that increases for each fixed crank angle, similar to control device 400.

While the missing tooth portion 153 is detected 2 times by the crank position sensor 150 during two revolutions of the crankshaft 59, it is not possible to determine which of the crank count values corresponds to the crank angle of two revolutions the detected missing tooth portion 153 corresponds to when the cam position sensor 160 fails.

Then, in the control device 400, when the cam position sensor 160 such as the signal is not output from the intake side cam position sensor 160 and the like has failed, the count calculating unit 302 temporarily determines one of the two crank angles corresponding to the missing tooth portion 153 as the crank angle based on the detection of the missing tooth portion 153 at the time of starting the engine 50. For example, in the control device 400, "90 ° CA" out of "90 ° CA" and "450 ° CA" which are two crank angles corresponding to the tooth missing portion 153 as shown in fig. 9 is temporarily determined as the crank angle.

The count calculating unit 302 calculates a value of the crank count based on the temporarily determined crank angle. The engine control unit 300 controls the engine 50 based on the crank count thus calculated, attempting to start.

The routine shown in fig. 16 is executed by the engine control unit 300 when starting the engine 50 in a state where such a cam position sensor 160 has failed.

As shown in fig. 16, when starting the routine, the engine control unit 300 first determines in the process of step S700 whether or not the start-up of the engine 50 has failed. The determination as to whether or not the start-up has failed is made based on whether or not the start-up of the engine 50 has been completed within a prescribed time. That is, when the start of the engine 50 is completed within a predetermined time, the engine control unit 300 determines that the start of the engine 50 was successful at the time when the start of the engine 50 was completed. On the other hand, when the engine 50 is not started even if the predetermined time elapses, the engine control unit 300 determines that the engine 50 is not started.

In the case where it is determined in the process of step S700 that the start-up of the engine has failed (yes in step S700), engine control unit 300 advances the process to step S710. Then, in the process of step S710, engine control unit 300 switches the value of the crank count.

Specifically, in the process of step S710, the count calculating unit 302 recalculates the crank count with regard to "450 ° CA" out of the two crank angles corresponding to the tooth missing portion 153, that is, "90 ° CA" and "450 ° CA", which are not the temporarily determined crank angle, as the correct crank angle. When the crank count is switched in this way, engine control unit 300 temporarily ends the routine. Then, based on the newly recalculated crank count, engine control unit 300 restarts engine 50.

On the other hand, when it is determined that the engine start is successful in the process of step S700 (step S700: no), the engine control unit 300 directly ends the routine without executing the process of step S710. Then, the count calculating unit 302 continues to calculate the crank count based on the temporarily determined crank angle, and the engine control unit 300 controls the engine 50 based on the crank count calculated by the count calculating unit 302.

In this way, in the control device 400, when the cam position sensor 160 fails, one of the two crank angles corresponding to the missing tooth portion 153 is temporarily determined as the crank angle based on the detection of the missing tooth portion 153 by the crank position sensor 150, and the value of the crank count is calculated based on the temporarily determined crank angle. The engine 50 is controlled based on a value of the crank count calculated based on the temporarily determined crank angle.

In addition, in the control device 400, when the start-up using the value of the crank count calculated based on the temporarily determined crank angle fails, the crank count is recalculated based on the other crank angle, which is not the temporarily determined crank angle, of the two crank angles corresponding to the missing teeth portion 153. Then, the control device 400 uses the recalculated crank count to try again to start the engine 50. Therefore, even when the start-up based on the temporarily determined one crank angle fails, the start-up of the engine 50 can be completed by the start-up using the crank count recalculated based on the other crank angle.

After the completion of the start-up, the count calculating unit 302 counts the edges of the crank angle signal, and continues the calculation of the crank count. And, the engine control unit 300 controls the engine 50 based on the crank count.

The crank position sensor 150 cannot detect the crank angle when the rotational speed of the crankshaft 59 is extremely slow. Further, since the rotation direction of the crankshaft 59 cannot be specified, when the crankshaft 59 rotates in the reverse rotation direction due to the compression reaction force of the air in the cylinder immediately before the engine 50 is stopped, the crank angle cannot be grasped.

In control device 400, since 1 st motor generator 11 and 2 nd motor generator 12 are coupled to crankshaft 59 via planetary gear mechanism 13, the rotation angle of crankshaft 59 can be estimated based on the rotation angle detected by the resonators (resolvers) provided in 1 st motor generator 11 and 2 nd motor generator 12.

Then, in the control device 400, when the rotational speed of the crankshaft 59 is extremely low and when the rotation in the reverse rotational direction occurs, the rotational angle of the crankshaft 59 is estimated with reference to the transition of the rotational angle of the 1 st motor generator 11 and the transition of the rotational angle of the 2 nd motor generator 12 detected by the resonator. Based on the estimated rotation angle of the crankshaft 59, the count calculating unit 302 calculates a crankshaft count. In this way, in the control device 400, the count calculating unit 302 also continuously calculates the crank count from the time when the operation of the engine 50 is stopped to the time when the engine 50 is started next.

In the control device 400, the next time the engine 50 is started, the engine is started based on the grasped value of the crank count without waiting for detection of the missing teeth portion 153. Therefore, even if the cam position sensor 160 fails, the start of the engine 50 can be completed promptly.

However, if the rotation angle of the 1 st motor generator 11 or the rotation angle of the 2 nd motor generator 12 cannot be detected due to a failure of the resonator or the like, the rotation angle of the crankshaft 59 cannot be estimated.

Then, in the control device 400, the routine shown in fig. 17 is repeatedly executed during the operation of the engine 50 in which the 3 rd intermittent stop prohibition flag, which is one of the intermittent stop prohibition flags, is inactive while the cam position sensor 160 is in a failure state. The routine shown in fig. 17 is executed by the system control unit 100.

As shown in fig. 17, when starting the routine, the system control unit 100 first determines in the process of step S800 whether the rotation angle of the 1 st motor generator 11 or the rotation angle of the 2 nd motor generator 12 cannot be detected and the rotation angle is unknown. That is, the system control unit 100 determines whether or not the crank count cannot be calculated by referring to the rotation angle of the 1 st motor generator 11 and the rotation angle of the 2 nd motor generator 12 through the process of step S800.

When it is determined that the rotation angle is unknown in the process of step S800 (yes in step S800), the system control unit 100 advances the process to step S810. Then, system control unit 100 causes nonvolatile memory 104 to store an abnormality flag, which is information indicating that an abnormality has occurred in the motor generator whose rotation angle is unknown in the process of step S810. When the abnormality flag is stored in the nonvolatile memory 104, the system control unit 100 causes the warning display unit 110 to display information indicating that an abnormality has occurred.

Next, the system control unit 100 stores the 3 rd intermittent stop prohibition flag in the nonvolatile memory 104 in the process of step S820. Thereby, the 3 rd intermittent stop prohibition flag becomes active. When the 3 rd intermittent stop prohibition flag is thus activated, the system control unit 100 temporarily ends the routine. In the initial state, the 3 rd intermittent stop prohibition flag is not stored in the nonvolatile memory 104 but is deactivated.

As described above, the stop prohibition portion 101 executes the intermittent stop prohibition process that prohibits the operation of the engine 50 from being stopped by the intermittent stop control when the intermittent stop prohibition flag is activated. As described with reference to fig. 17, when the system control unit 100 becomes a state in which the crank count cannot be calculated with reference to the rotation angle of the 1 st motor generator 11 and the rotation angle of the 2 nd motor generator 12, the 3 rd intermittent stop prohibition flag is activated. That is, in the control device 400, when the cam position sensor 160 fails and the calculation of the crank count cannot be performed with reference to the rotation angle of the motor generator, the stop prohibition unit 101 executes the intermittent stop prohibition process to keep the engine running.

When the operation of the engine 50 is stopped by the intermittent stop control in the event of a failure of the cam position sensor 160, it is necessary to perform the startup again by using the crank angle temporarily determined by the detection of the missing tooth portion 153. The restarting of the cam position sensor 160 in the failed state may fail. In contrast, since the control device 400 executes the intermittent stop prohibition process to keep the engine 50 running, it is possible to suppress the execution of the restart that may fail and avoid the failure of the start.

The abnormality flag is cleared from the nonvolatile memory 104 when an abnormality is removed, for example, by repair in a repair factory. In addition, along with the clearing of the abnormality flag, the 3 rd intermittent stop prohibition flag is also cleared.

The operation and effects of the present embodiment will be described.

(Intermittent stop prohibition processing involving diagnostic processing)

(1-1) In the control device 400, the temporary determination flag is stored in the nonvolatile memory 104 that can be kept stored even when the power supply is stopped by turning off the system main switch 120. Therefore, even if the system main switch 120 is turned off before the diagnosis of the intention of abnormality is made and the real determination flag is set to be active, when the system main switch 120 is subsequently set to be on, it is possible to recognize that the diagnosis is underway based on the temporary determination flag stored in the nonvolatile memory 104.

When the temporary determination flag is stored, the stop prohibition unit 101 prohibits the stop of the operation of the engine 50 by the intermittent stop control. Therefore, even when the system main switch 120 is turned off during diagnosis, when the system main switch 120 is turned on next time, if the operation of the engine 50 is started, the stop of the operation of the engine 50 by the intermittent stop control is immediately prohibited, and the operation of the engine 50 is continued. Therefore, the opportunity for execution of the diagnostic process increases, and the diagnosis can be completed promptly, as compared with a case where the stop of the operation of the engine 50 by the intermittent stop control is not prohibited.

(1-2) When stopping the operation of the engine 50 by the intermittent stop control is prohibited, the operation of the engine 50 continues, and therefore, the fuel consumption increases. That is, the effect of suppressing the fuel consumption to be obtained by the intermittent stop control becomes unavailable. In contrast, in the control device 400, as described with reference to fig. 13, it is possible to suppress the stop stroke of the engine 50 from being continued more than 2 times because the temporary determination flag is stored. Therefore, it is possible to ensure the harmony between the execution opportunity of the diagnosis and the suppression of the fuel consumption, and to suppress the excessive increase of the fuel consumption.

(Intermittent stop prohibition processing involving learning processing)

(2-1) Since the engine 50 is operated using fuel in an inefficient state at a lower vehicle speed, the fuel consumption increases by executing the intermittent stop prohibition process at a lower vehicle speed. Therefore, in order to suppress the fuel consumption, it is preferable to set the vehicle speed threshold to a large value, set the vehicle speed at which the intermittent stop prohibition process is executed to a high vehicle speed side, and suppress the operation of the engine in a state of low efficiency by the intermittent stop control.

However, as the operation of the engine 50 continues, the time-dependent changes in the control target, for example, deposition of the deposit in the throttle valve 53 and the like accumulate, and therefore, the necessity of updating the learning value increases. In contrast, in the control device 400, the vehicle speed threshold becomes smaller as the cumulative amount of work of the engine 50 increases from the completion of learning, and the chance of executing the intermittent stop prohibition process increases, and the intermittent stop prohibition process becomes easier to execute. That is, in the control device 400, the execution opportunity of the intermittent stop prohibition processing is increased and the update opportunity of the learning value is ensured in accordance with an increase in the necessity of updating the learning value with an increase in the cumulative amount of the engine 50. Therefore, according to the control device 400, it is possible to achieve a reconciliation between ensuring the update opportunity of the learning value and suppressing the fuel consumption by the execution of the intermittent stop control.

(2-2) When the correction amount in the control is large, it is preferable to update the learning value promptly. In contrast, in the control device 400, as the correction amount increases, the vehicle speed threshold decreases, and the execution opportunity of the intermittent stop prohibition process increases. That is, according to the control device 400, when the correction amount is large, the opportunity for updating the learning value can be increased, and the control deviation can be quickly eliminated.

(Control concerning engine starting in the event of failure of the cam position sensor)

(3-1) In the control device 400, when the cam position sensor 160 fails, one of the two crank angles corresponding to the missing tooth portion 153 is temporarily determined as the crank angle based on the detection of the missing tooth portion 153 by the crank position sensor 150. Engine control section 300 controls engine 50 based on the value of the crank count calculated from the temporarily determined crank angle. Therefore, even if the cam position sensor 160 malfunctions, the engine 50 can be started with a probability of about 50%.

(3-2) In the control device 400, when the start-up using the value of the crank count calculated based on the temporarily determined crank angle fails, the crank count is recalculated based on the other crank angle, which is not the temporarily determined crank angle, of the two crank angles corresponding to the missing teeth portion 153. Then, starting of the engine 50 is attempted again using the recalculated crank count. Therefore, even when the start-up based on the temporarily determined one crank angle fails, the start-up of the engine 50 can be completed by the start-up using the crank count recalculated based on the other crank angle.

(3-3) In the control device 400, even when the operation of the engine 50 is stopped, the rotation angle of the crankshaft 59 is estimated with reference to the rotation angle of the motor generator, so that the crank angle during the period in which the engine 50 is stopped can be grasped. Therefore, the engine can be started based on the grasped crank angle at the next engine start. Therefore, even if the cam position sensor 160 fails, the start of the engine 50 can be completed promptly.

(3-4) In the control device 400, when the state in which the crank count cannot be calculated by referring to the rotation angle of the 1 st motor generator 11 and the rotation angle of the 2 nd motor generator 12 is established, the operation of the engine 50 is continued. Therefore, the restart can be suppressed, which may be a failure, and the failure of the start can be avoided.

The present embodiment can be modified as follows. The present embodiment and the following modifications can be combined and implemented within a range that is not technically contradictory.

The control device 400 is applied to a plug-in hybrid vehicle in which the battery 30 can be charged by the external power source 40, but may be applied to a non-plug-in hybrid vehicle.

Although the example in which the engine 50 includes the intake-side valve timing changing mechanism 56 and the exhaust-side valve timing changing mechanism 56 is shown, the control device 400 may be applied to a hybrid vehicle including an engine without the valve timing changing mechanism 56.

Specifically, the present invention is applicable to a hybrid vehicle equipped with an engine having only the intake-side valve timing changing mechanism 56, an engine having only the exhaust-side valve timing changing mechanism 56, and an engine having no valve timing changing mechanism 56.

The expression of the value of the crank count is not limited to the expression of "1", "2", "3", … … which are increased one by one. For example, 30 or 30 crankshaft angles such as "0", "30", "60", … … may be increased according to the corresponding crankshaft angle. Of course, it is not necessary to increase the crank angle by 30 or 30. For example, the number of 5 may be increased by 5 such as "0", "5", and "10".

Although an example in which the crank count is increased every 30 ° CA is shown, the manner of increasing the crank count is not limited to this. For example, the number of the elements may be increased for every 10 ° CA, or the number may be increased at intervals longer than 30 ° CA. That is, in the above embodiment, the configuration was adopted in which the crank count was increased every 3 edges, and the crank count was increased every 30 ° CA, but the number of edges required for the increase may be changed as appropriate. For example, the following constitution may be adopted: every time 1 edge is counted, the crank count is increased, and every 10 ° CA, the crank count is increased.

The valve timing changing mechanism 56 may be a hydraulic drive type mechanism. In this case, the oil control valve that controls the oil pressure is reciprocated during the release operation.

Not all of the illustrated diagnostic processes may be performed. The diagnostic process to be performed is not limited to the illustrated process. When the intermittent stop prohibition processing is executed in the case of executing the diagnosis processing that is unable to diagnose the occurrence of the abnormality when the engine 50 is not operating, the effect that the opportunity of executing the diagnosis can be ensured and the diagnosis can be completed promptly can be obtained, as in the above-described embodiment.

In the diagnosis process, an example is shown in which a determination is made that an abnormality has occurred when the learning value reaches the upper limit or the lower limit when the learning process is executed, but the method of abnormality diagnosis is not limited to such a scheme. For example, it may be set as: when the deviation between the target value and the detected value is large, it is determined that an abnormality has occurred.

The example in which the intermittent stop prohibition processing is limited to two strokes when the temporary determination flag is activated is shown, but the number of strokes in which the intermittent stop prohibition processing is permitted to continue is not limited to "2". For example, "3" or more may be used. In addition, the structure of limiting persistence may be omitted.

As described with reference to fig. 11, in the above embodiment, after the temporary determination flag is activated, when the normal count becomes "3" or more, the temporary determination flag is cleared, and the display indicating that an abnormality has occurred is stopped. In contrast, the threshold value of the normal count, which is the condition for clearing the temporary determination flag, is not limited to "3". For example, the value may be smaller than "3" or may be equal to or greater than "4".

The following examples are shown: when the temporary determination routine makes an abnormal determination and the temporary determination flag becomes active, a diagnosis of occurrence of an abnormality is made and the real determination flag is made active when the real determination routine makes an abnormal determination. On the other hand, the determination method of the diagnosis in the diagnosis process, that is, the condition under which the diagnosis is finally made, may be appropriately changed. For example, it may be: when the determination of the intention of abnormality by the provisional determination routine is continued a plurality of times, diagnosis of occurrence of abnormality is made, and the true determination flag is activated.

Although the control device 400 is shown as an example of the system control unit 100, the power control unit 200, and the engine control unit 300, the configuration of the control device is not limited to this configuration. For example, the control device may be physically configured as one device. The control device may be composed of 4 or more units.

While the example in which the threshold value calculating unit 10 calculates a smaller value as the correction amount is larger in the control of the subject to learn the learning value is shown, the process of step S510 may be omitted, and the threshold value calculating unit 103 may calculate the vehicle speed threshold value based on the integrated amount of work regardless of the correction amount.

While the example in which the work amount calculation unit 102 calculates the cumulative travel distance of the hybrid vehicle 10 as the index value of the cumulative work amount is shown, the index value of the cumulative work amount is not limited to this. For example, the following constitution may be adopted: the work amount calculation unit 102 calculates the cumulative intake air amount of the engine 50 from the completion of learning of the learning value by the latest learning process as an index value of the cumulative work amount.

The more the cumulative intake air amount, the more the cumulative amount of work of the engine 50 can be said to be. Therefore, by calculating the cumulative intake air amount of the engine 50 from the completion of learning as the index value of the cumulative amount of operation of the engine 50 from the completion of learning, the cumulative amount of operation of the engine 50 from the completion of learning can be estimated based on the calculated index value.

In addition, for example, the following constitution may be adopted: the work amount calculation unit 102 calculates the cumulative work time of the engine 50 from the completion of learning of the learning value by the latest learning process as the index value of the cumulative work amount.

The longer the cumulative operating time, the more the cumulative operating load of the engine 50 can be said to be. Therefore, by calculating the cumulative operating time of the engine 50 from the completion of learning as the index value of the cumulative operating amount of the engine 50 from the completion of learning, the cumulative operating amount of the engine 50 from the completion of learning can be estimated based on the calculated index value.

The following examples are shown: the crank angles corresponding to the missing teeth 153 are "90 ° CA" and "450 ° CA", and when the cam position sensor 160 fails, the crank angle at which the missing teeth 153 are detected is temporarily determined to be "90 ° CA". However, the temporarily determined crank angle may be set to "450 ° CA". In this case, in the processing of step S710, "90 ° CA" is regarded as the correct crank angle, and the crank count is recalculated.

That is, in the case where the crankshaft 59 rotates two times, since the two crank angles corresponding to the missing teeth portion 153 are separated by 360 ° CA, the other crank angle is increased or decreased by the amount corresponding to one rotation with respect to the one crank angle.

Therefore, when the start of the engine 50 has failed, the count calculating unit 302 recalculates the crank count based on the crank angle that is increased or decreased by the amount corresponding to one revolution from the temporarily determined crank angle, and restarts the engine 50 based on the recalculated crank count.

The process described with reference to fig. 16 of switching the value of the crank count when the start-up based on the temporarily determined crank angle has failed may be omitted. If the start is performed at least by temporarily determining one of the two crank angles corresponding to the tooth missing portion 153, the start can be successfully performed with a probability of about 50%.

The intermittent stop may be inhibited when the crank count cannot be calculated with reference to the rotation angle of the motor generator. In this case, when the engine is started next, the crank angle is temporarily determined, and the process described with reference to fig. 16 is executed to try the engine.

The following configuration may be omitted: during the period in which the operation of the engine 50 is stopped, the calculation of the crank count is continued with reference to the rotation angle of the motor generator.

Although the 3 rd intermittent stop prohibition flag is stored in the nonvolatile memory 104, the 3 rd intermittent stop prohibition flag may be stored in a memory that is cleared when the power supply is stopped, instead of the nonvolatile memory 104. In this case, when the routine described with reference to fig. 17 is executed next time the engine 50 is operated, the 3 rd intermittent stop prohibition flag is set to be activated.

When the engine 50 is operated, the engine rotation speed is difficult to stabilize immediately after the change in the driving force by the 2 nd motor generator 12, the change in the power generation amount by the 1 st motor generator 11, or the like. Therefore, ISC learning may also be prohibited at this time so that ISC learning is not performed. In addition, the intermittent stop prohibition processing for ensuring the execution opportunity of the ISC learning may not be executed at this time. In addition, the ISC learning may not be prohibited, and the intermittent stop prohibition processing for securing the execution opportunity of the ISC learning may not be executed.

When the fuel increase correction is performed at the time of starting the engine 50 or the like, the engine speed is also difficult to stabilize. Therefore, it is also possible to prohibit ISC learning without performing ISC learning at the time of performing the fuel increase correction and immediately after the fuel increase correction. In addition, the intermittent stop prohibition processing for ensuring the execution opportunity of the ISC learning may not be executed at this time. In addition, the ISC learning may not be prohibited, and the intermittent stop prohibition processing for securing the execution opportunity of the ISC learning may not be executed.

In order to ensure the S/N ratio, which is the ratio of the signal to the noise, the ignition timing is retarded and the intake air amount is increased when the imbalance diagnosis process is performed. Therefore, there is a possibility that a deviation is generated in the learning value of ISC learning. Then, ISC learning may not be performed when the imbalance diagnosis process is performed.

In the case of ISC learning, even when there is a deviation in the learning value in the case of other control, if the magnitude of the deviation due to the influence of the control can be grasped in advance, the deviation can be canceled out and learned. Therefore, when such cancellation is performed, the intermittent stop prohibition processing is performed as in the above embodiment to perform learning. For example, when the driving force of the 2 nd motor generator 12 is changed, the power generation amount of the 1 st motor generator 11 is changed, the torque of the crankshaft 59 is changed, and thus, in that case, ISC learning cannot be performed accurately, but the torque is offset by taking the torque change into consideration in advance, and learning can be performed. In this case, the intermittent stop prohibition can be implemented to perform learning as in the above embodiment.

Further, during idling operation, the following is made: the energization of the 1 st motor generator 11 is controlled, and the load generated by the 1 st motor generator 11 is not applied to the crankshaft 59. However, in this control, there is an error for each rotation speed of the 1 st motor generator 11. As a result, the learning value during ISC learning varies. Then, a correction amount may be set for each rotation speed of the 1 st motor generator, and the electric current to the 1 st motor generator 11 may be controlled by performing the correction, thereby performing ISC learning. Since the rotation speed of the 1 st motor generator 11 is proportional to the vehicle speed, the correction amount may be calculated based on the vehicle speed.

As an example of determining whether or not it is impossible to calculate the crank count with reference to the rotation angle of the motor generator, a failure of the resonator is illustrated. However, the cause of the failure in the resonator is not limited to the failure of the resonator, and the crankshaft count cannot be calculated with reference to the rotation angle of the motor generator. For example, in the case of a single-motor hybrid vehicle as shown in fig. 18, the connection between the crankshaft 59 of the engine 50 and the drive motor 210 is released by the clutch 230, and the crank count cannot be calculated with reference to the rotation angle of the drive motor 210.

An example of control in the case of such a configuration will be described with reference to fig. 18 and 19. As shown in fig. 18, the hybrid vehicle is provided with a drive motor 210 between the engine 50 and a transmission 220. Further, a clutch 230 is interposed between the drive motor 210 and the engine 50. The drive motor 210 is coupled to an input shaft 221 of a transmission 220, and a drive shaft 24 of a wheel 23 is coupled to an output shaft 222 of the transmission via a differential mechanism 22.

The control device 400 includes a stop prohibition unit 101 and a count calculation unit 302. The control device 400 controls the engine 50, the clutch 230, and the drive motor 210. In this control device 400, instead of the routine shown in fig. 17, the routine shown in fig. 19 is executed. This routine is repeatedly executed by the control device 400 during the operation of the engine 50 in which the 3 rd intermittent stop flag is deactivated in a state where the cam position sensor 160 is malfunctioning.

As shown in fig. 19, when starting the routine, the control device 400 first determines whether or not the clutch 230 is disconnected (OFF) from the drive motor 210, which is the state in which the crankshaft 59 is disconnected from the drive motor 210, in the process of step S900. That is, the control device 400 determines whether or not the state where the crank count cannot be calculated with reference to the rotation angle of the drive motor 210 is established by the processing of step S900.

When it is determined that the clutch is disengaged in the process of step S900 (yes in step S900), the control device 400 advances the process to step S910. Then, the control device 400 stores the 3 rd intermittent stop prohibition flag in the memory in the process of step S910. Thereby, the 3 rd intermittent stop prohibition flag becomes active. When the 3 rd intermittent stop prohibition flag is thus activated, the control device 400 temporarily ends the routine. In the initial state, the 3 rd intermittent stop prohibition flag is not stored in the memory but is deactivated. In addition, in the case of the control device 400, the memory storing the 3 rd intermittent stop prohibition flag is not a nonvolatile memory, and therefore, in the case where the power supply is stopped, the 3 rd intermittent stop prohibition flag is cleared.

ON the other hand, when it is determined that the state of engagement (ON) is established as a state in which the crankshaft 59 is connected to the drive motor 210 so that the clutch is not disconnected in the process of step S900 (step S900: no), the control device 400 does not execute the process of step S910, and the routine is temporarily terminated.

In the case of adopting such a configuration, the stop prohibition unit 101 can execute the intermittent stop prohibition processing to continue the operation of the engine when the calculation of the crank count cannot be performed with reference to the rotation angle of the motor generator. Therefore, the restart can be suppressed, which may be a failure, and the failure of the start can be avoided.

Technical ideas that can be grasped from the above embodiments and modified examples are described. (1) A control device for a hybrid vehicle, which is applied to a hybrid vehicle provided with an engine and a motor as driving force sources, and which executes intermittent stop control for automatically stopping and restarting an operation of the engine and learning processing for learning a learning value used for controlling the engine, the control device comprising: a stop prohibition portion that executes an intermittent stop prohibition process that prohibits stopping of the operation of the engine by the intermittent stop control; a work amount calculation unit that calculates an index value indicating an accumulated work amount of the engine from completion of learning of the learning value by the latest learning process; and a threshold value calculating unit that calculates a vehicle speed threshold value based on the index value calculated by the work amount calculating unit, wherein the threshold value calculating unit calculates a smaller value as the vehicle speed threshold value based on the index value, and wherein the stop prohibiting unit executes the intermittent stop prohibiting process when the vehicle speed of the hybrid vehicle is equal to or greater than the vehicle speed threshold value.

As the engine operation continues, the time-dependent changes in the control target, for example, deposition of deposits in the throttle valve, etc. accumulate, and therefore, the necessity of updating the learned value increases. On the other hand, according to the above configuration, the vehicle speed threshold becomes smaller as the amount of engine operation increases from the completion of learning, and the chance of executing the intermittent stop prohibition process increases, and the intermittent stop prohibition process becomes easier to execute. That is, according to the above configuration, the execution opportunity of the intermittent stop prohibition processing can be increased in accordance with an increase in the necessity of updating the learning value with an increase in the amount of engine operation, so that the adjustment between the execution opportunity of the learning value and the fuel consumption amount to be suppressed by the execution of the intermittent stop control can be ensured.

(2) According to the control device for a hybrid vehicle described in (1), the threshold value calculating unit calculates a smaller value as the vehicle speed threshold value as the correction amount in the control of the subject of learning the learning value is larger.

It is preferable to update the learning value promptly when the correction amount in the control is large. On the other hand, according to the above configuration, as the correction amount is larger, the vehicle speed threshold is smaller, and the execution opportunity of the intermittent stop prohibition process increases. That is, when the correction amount is large, the learning value update opportunity can be increased, and the control deviation can be quickly eliminated.

(3) The control device for a hybrid vehicle according to (1) or (2), wherein the workload calculating unit calculates, as the index value, an accumulated travel distance of the hybrid vehicle from completion of learning of the learning value by the latest learning process.

The longer the cumulative travel distance, the more likely the cumulative workload of the engine becomes. Therefore, by calculating the cumulative travel distance from completion of learning as an index value of the cumulative amount of operation of the engine from completion of learning, the cumulative amount of operation of the engine from completion of learning can be estimated based on the calculated index value.

(4) The control device for a hybrid vehicle according to (1) or (2), wherein the workload calculating unit calculates an integrated intake air amount of the engine from completion of learning of the learning value by the latest learning process as the index value.

The more the cumulative intake air amount, the more the cumulative operation amount of the engine. Therefore, by calculating the cumulative intake air amount of the engine from the completion of learning as the index value of the cumulative amount of operation of the engine from the completion of learning, the cumulative amount of operation of the engine from the completion of learning can be estimated based on the calculated index value.

(5) The control device for a hybrid vehicle according to (1) or (2), wherein the workload calculating unit calculates, as the index value, an accumulated operating time of the engine from completion of learning of the learning value by the latest learning process.

The longer the cumulative operating time, the more the cumulative operating load of the engine can be said to be. Therefore, by calculating the cumulative operating time of the engine from completion of learning as an index value of the cumulative operating amount of the engine from completion of learning, the cumulative operating amount of the engine from completion of learning can be estimated based on the calculated index value.

(6) A control device for a hybrid vehicle, which is applied to a hybrid vehicle provided with an engine and a motor as driving force sources, and which executes intermittent stop control for automatically stopping and restarting the operation of the engine, wherein the control device is provided with a count calculation unit for temporarily determining a crank angle based on detection of a pulse signal output by a crank position sensor for each predetermined crank angle accompanying rotation of a crankshaft of the engine, detection of a missing tooth portion occurring once during one revolution of the crankshaft, and detection of a signal output by a cam position sensor for detecting arrival of a specific cam angle of a cam shaft rotating in conjunction with the crankshaft for one revolution, and for temporarily determining a crank angle based on detection of the missing tooth portion by the crank position sensor when the cam position sensor fails, and for temporarily controlling the calculated crank angle based on the calculated value when the cam position sensor fails.

Since the missing tooth portion is detected 2 times during two revolutions of the crankshaft, the crank angle corresponding to the missing tooth portion includes two of the crank angle in the 1 st revolution and the crank angle in the 2 nd revolution after being separated from the crank angle in the 1 st revolution by 360 ° CA.

According to the above configuration, when the cam position sensor fails, one of the two crank angles corresponding to the missing tooth portion is temporarily determined as the crank angle based on the detection of the missing tooth portion by the crank position sensor, and the value of the crank count is calculated based on the temporarily determined crank angle. The engine is controlled based on a value of the crank count calculated from the temporarily determined crank angle. Therefore, even if the cam position sensor fails, by controlling the engine based on the value of the crank count calculated from the temporarily determined crank shaft, the engine can be started with a probability of about 50%.

(7) According to the control device for a hybrid vehicle described in (6), when the start of the engine performed based on the value of the crank count calculated from the temporarily determined crank angle is successful, the count calculating unit continues the calculation of the crank count based on the temporarily determined crank angle, and when the start of the engine performed based on the value of the crank count calculated from the temporarily determined crank angle has failed, the count calculating unit recalculates the crank count based on the crank angle increased or decreased by an amount corresponding to one revolution from the temporarily determined crank angle, and restarts the engine based on the recalculated crank count.

According to the above configuration, when starting using the value of the crank count calculated based on the temporarily determined crank angle has failed, the crank count is recalculated based on the other crank angle, which is not the temporarily determined crank angle, of the two crank angles corresponding to the missing teeth portion, and starting of the engine is retried using the recalculated crank count. Therefore, even when the start-up based on the temporarily determined one crank angle has failed, the start-up of the engine can be completed by the start-up using the crank count recalculated based on the other crank angle.

(8) The control device for a hybrid vehicle according to (6) or (7), wherein the count calculating unit calculates the crank count by referring to a rotation angle of the motor. The crank position sensor cannot detect the crank angle when the rotational speed of the crankshaft is extremely slow. Further, since the rotation direction of the crankshaft cannot be specified, the crank angle cannot be grasped when the crankshaft rotates in the opposite rotation direction immediately before the engine is stopped. In contrast, in the case of a hybrid vehicle that runs by a motor and an engine, the rotation angle of the crankshaft can be estimated based on the rotation angle of the motor that assists the driving of the engine. In this case, even when the rotational speed of the crankshaft is extremely low, such as when the engine is stopped, and rotation in the opposite rotational direction occurs, the rotational angle of the crankshaft can be estimated. Therefore, according to the above configuration, even when the operation of the engine is stopped, the rotation angle of the crankshaft can be estimated with reference to the rotation angle of the motor. If the crank angle during the engine stop period can be grasped in this manner, the engine can be started based on the grasped crank angle at the next engine start. Therefore, even if the cam position sensor fails, the start of the engine can be completed quickly.

(9) The control device for a hybrid vehicle according to (8) includes a stop prohibition unit that executes an intermittent stop prohibition process that prohibits stopping the operation of the engine by the intermittent stop control, and when the cam position sensor fails and the calculation of the crank count cannot be performed with reference to the rotation angle of the motor, the stop prohibition unit executes the intermittent stop prohibition process to continue the operation of the engine.

When the cam position sensor fails, if the operation of the engine is stopped by the intermittent stop control, it is necessary to perform the startup again using the crank angle temporarily determined by the detection of the missing tooth portion.

Restarting of the cam position sensor in a failure state may fail, and fuel may be wasted and unburned gas may be discharged as compared with a case where the operation of the engine is continued. In contrast, according to the above configuration, since the operation of the engine is continued, the restart that may fail can be suppressed, and the failure of the start can be avoided.

Claims

1. A control device for a hybrid vehicle, which is applied to a hybrid vehicle provided with an engine and a motor as driving force sources, and which executes intermittent stop control for automatically stopping and restarting the operation of the engine, the control device comprising:

a diagnostic unit that performs a diagnostic process for confirming whether or not an abnormality is present in the engine when the engine is running; and

A stop prohibition portion that executes an intermittent stop prohibition process that prohibits stopping of the operation of the engine by the intermittent stop control,

The diagnosis unit stores a temporary determination flag in a nonvolatile memory when the temporary determination flag is determined to be abnormal by the diagnosis process in a state in which the temporary determination flag is not stored in the nonvolatile memory, and performs diagnosis of the intention of the abnormality when the temporary determination flag is determined to be abnormal by the diagnosis process in a state in which the temporary determination flag is stored in the nonvolatile memory, and clears the temporary determination flag from the nonvolatile memory, the temporary determination flag being information indicating that the abnormality is likely to occur,

The stop prohibition portion executes the intermittent stop prohibition process when the temporary determination flag is stored in the nonvolatile memory,

The stop prohibition unit releases prohibition of stopping the engine by the temporary determination flag stored when the temporary determination flag stored is set to be on for a predetermined number of times, with the period during which the system main switch of the vehicle is turned on as one stroke.