JP7690907B2 - Hybrid vehicle control device - Google Patents

Description

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

There is known a hybrid vehicle that has an engine, a motor provided on the power transmission path between the engine and the drive wheels, a clutch provided on the power transmission path between the engine and the motor, and a crank angle sensor that detects the crank angle of the engine. In such a hybrid vehicle, when there is a request to start the stopped engine, the motor outputs the required torque required to crank the engine via the clutch, thereby starting the engine (see, for example, Patent Document 1).

JP 2013-091466 A

The torque required to crank the engine varies depending on the crank angle when the engine is stopped. Therefore, it is possible to change the torque output by the motor depending on the crank angle when the engine is stopped. However, there is a certain limit to the detection resolution of the crank angle sensor that detects the crank angle. For this reason, a difference will occur between the crank angle detected by the crank angle sensor when the engine is stopped and the actual crank angle when the engine is stopped, which may result in a lack of torque for cranking and reduced engine startability.

The present invention aims to provide a control device for a hybrid vehicle that ensures engine startability.

The above object can be achieved by a control device for a hybrid vehicle having an engine, a motor provided on a power transmission path between the engine and drive wheels, a clutch provided on the power transmission path between the engine and the motor, and a crank angle sensor that detects a crank angle of the engine, the control device including: a start control unit that starts the engine when there is a request to start the stopped engine by causing the motor to output a required torque required to crank the engine via the clutch; a crank angle acquisition unit that acquires a first angle detected by the crank angle sensor when the engine is stopped and a second angle detected by the crank angle sensor next to the first angle when the engine rotates in the forward rotation direction from the first angle; a calculation unit that calculates first and second required torques that are required to crank the engine when the crank angle when the engine is stopped is the first and second angles, respectively; and a selection unit that selects the larger of the first and second required torques as the required torque.

The crank angle acquisition unit may further acquire a third angle detected immediately before the first angle is detected by the crank angle sensor , the calculation unit may further calculate a third required torque that is required to crank the engine when the crank angle is the third angle when the engine is stopped, and the selection unit may select a maximum value from the first, second, and third required torques as the required torque.

The engine may include a pressure acquisition unit that acquires pressure in an intake passage downstream of a throttle valve of the engine, and the calculation unit may calculate the first and second required torques to be greater as the pressure increases.

The calculation unit may calculate the first and second required torques to be smaller the longer the elapsed time since the engine was stopped.

The present invention provides a control device for a hybrid vehicle that ensures engine startability.

FIG. 1 is a schematic diagram of a hybrid vehicle. FIG. 2 is a schematic diagram of the engine. FIG. 3A is an explanatory diagram of a structure for detecting a crank angle, and FIG. 3B is an explanatory diagram of a pulse signal output by the crank angle sensor. FIG. 4 is a map showing the relationship between the torque and the rotation speed of the motor. FIG. 5 is a flowchart showing an example of engine start control executed by the ECU. FIG. 6 is an example of a map that defines the torque required to crank the engine according to the crank angle when the engine is stopped.

[General configuration of hybrid vehicle]
1 is a schematic diagram of a hybrid vehicle 1. In the hybrid vehicle 1, a K0 clutch 14, a motor 15, a torque converter 18, and a transmission 19 are provided in this order in a power transmission path from an engine 10 to drive wheels 13. The engine 10 and the motor 15 are mounted as a power source for driving the hybrid vehicle 1. The engine 10 is, for example, a V6 gasoline engine, but the number of cylinders is not limited thereto, and may be an in-line gasoline engine or a diesel engine. The K0 clutch 14, the motor 15, the torque converter 18, and the transmission 19 are provided in a transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drive-coupled via a differential 12.

The K0 clutch 14 is provided between the engine 10 and the motor 15 on the power transmission path. The K0 clutch 14 receives a supply of hydraulic pressure from a released state and enters an engaged state, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 enters a released state in response to the cessation of the hydraulic pressure supply and cuts off the power transmission between the engine 10 and the motor 15. The engaged state is a state in which both engagement elements of the K0 clutch 14 are connected and the engine 10 and the motor 15 have the same rotation speed. The released state is a state in which both engagement elements of the K0 clutch 14 are separated.

The motor 15 is connected to the battery 16 via the inverter 17. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied from the battery 16, and also functions as a generator that generates power to charge the battery 16 in response to power transmission from the engine 10 and the drive wheels 13. The power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

The inverter 17 is controlled by the ECU 100 described below, and converts the DC voltage from the battery 16 to an AC voltage, or converts the AC voltage from the motor 15 to a DC voltage. In the case of power running in which the motor 15 outputs torque, the inverter 17 converts the DC voltage of the battery 16 to an AC voltage and adjusts the power supplied to the motor 15. In the case of regenerative running in which the motor 15 generates power, the inverter 17 converts the AC voltage from the motor 15 to a DC voltage and adjusts the power supplied to the battery 16.

The torque converter 18 is a fluid coupling with a torque amplification function. The transmission 19 is a stepped automatic transmission that switches the gear ratio in multiple stages by changing the gear stage, but is not limited to this and may be a continuously variable automatic transmission. The transmission 19 is provided between the motor 15 and the drive wheels 13 on the power transmission path. The motor 15 and the transmission 19 are connected via the torque converter 18. The torque converter 18 is provided with a lock-up clutch 20 that receives a supply of hydraulic pressure and enters an engaged state to directly connect the motor 15 and the transmission 19.

The transmission unit 11 is further provided with an oil pump 21 and a hydraulic control mechanism 22. The hydraulic pressure generated by the oil pump 21 is supplied to the K0 clutch 14, the torque converter 18, the transmission 19, and the lock-up clutch 20 via the hydraulic control mechanism 22. The hydraulic control mechanism 22 is provided with hydraulic circuits for the K0 clutch 14, the torque converter 18, the transmission 19, and the lock-up clutch 20, and various hydraulic control valves for controlling their operating hydraulic pressures. A wet clutch may be provided instead of the torque converter 18.

The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as part of the hybrid vehicle. The ECU 100 is an electronic control unit that includes a calculation processing circuit that performs various calculation processes related to vehicle driving control, and a memory that stores control programs and data. The ECU 100 is an example of a hybrid vehicle, and functionally realizes a start control unit, a crank angle acquisition unit, a calculation unit, a selection unit, and a pressure acquisition unit, which will be described in detail later.

The ECU 100 controls the operation of the engine 10 and the motor 15. Specifically, the ECU 100 controls the torque and rotation speed of the engine 10 by controlling the throttle opening, ignition timing, and fuel injection amount of the engine 10. The ECU 100 controls the rotation speed and torque of the motor 15 by controlling the inverter 17 to adjust the amount of power exchanged between the motor 15 and the battery 16. The ECU 100 also controls the operation of the K0 clutch 14, the lock-up clutch 20, and the transmission 19 through the control of the hydraulic control mechanism 22.

The ECU 100 receives signals from an ignition switch 71, a crank angle sensor 72, a motor revolution speed sensor 73, an accelerator opening sensor 74, an air flow meter 75, a pressure sensor 76, and a water temperature sensor 77. The crank angle sensor 72 detects the rotation speed of the crankshaft of the engine 10. The motor revolution speed sensor 73 detects the rotation speed of the output shaft of the motor 15. The accelerator opening sensor 74 detects the accelerator pedal opening, which is the amount of depression of the accelerator pedal by the driver. The air flow meter 75 detects the amount of intake air of the engine 10. The pressure sensor 76 detects the pressure in the intake passage 35 downstream of the throttle valve 40 (described later) (hereinafter referred to as the intake manifold pressure). The water temperature sensor 77 detects the temperature of the cooling water of the engine 10.

The ECU 100 runs the hybrid vehicle in either the motor mode or the hybrid mode. In the motor mode, the ECU 100 releases the K0 clutch 14 and runs the vehicle using the power of the motor 15. In the hybrid mode, the ECU 100 switches the K0 clutch 14 to an engaged state and runs the vehicle using at least the power of the engine 10. The hybrid mode includes a mode in which the vehicle runs using only the power of the engine 10, and a mode in which the motor 15 is powered and the vehicle runs using both the engine 10 and the motor 15 as power sources.

The driving mode is switched based on the vehicle's required driving force, which is calculated from the vehicle speed and accelerator opening, and the state of charge of the battery 16. For example, when the required driving force is relatively small and the SOC (State of Charge), which indicates the amount of charge stored in the battery 16, is relatively high, the motor mode, in which the engine 10 is stopped, is selected to improve fuel efficiency. When the required driving force is relatively large or the SOC of the battery 16 is relatively low, the hybrid mode, in which the engine 10 is driven, is selected.

The ECU 100 executes intermittent operation control to automatically stop the engine 10 when a predetermined stop condition is met, and to start the automatically stopped engine 10 when a predetermined start condition is met. For example, when the accelerator opening becomes zero in the hybrid mode, the ECU 100 automatically stops the engine 10, assuming that the automatic stop condition is met. Also, when the accelerator opening becomes greater than zero, for example, the ECU 100 executes start control to automatically start the engine 10, assuming that the start condition is met. When automatically stopping, the ECU 100 releases the K0 clutch 14 to stop combustion. When automatically starting, the ECU 100 cranks the engine 10 by the motor 15 via the K0 clutch 14 to start combustion, and then engages the K0 clutch 14.

[General configuration of engine]
Fig. 2 is a schematic diagram of the engine 10. The engine 10 has cylinders 30, pistons 31, connecting rods 32, a crankshaft 33, an intake passage 35, an intake valve 36, an exhaust passage 37, and an exhaust valve 38. Only one of the multiple cylinders 30 of the engine 10 is shown in Fig. 2. An air-fuel mixture is burned in the cylinder 30. A piston 31 is accommodated in each cylinder 30 so as to be capable of reciprocating, and is connected to a crankshaft 33, which is an output shaft of the engine 10, via a connecting rod 32. The connecting rod 32 converts the reciprocating motion of the piston 31 into the rotational motion of the crankshaft 33.

The intake passage 35 is connected to the intake port of each cylinder 30 via an intake valve 36. The exhaust passage 37 is connected to the exhaust port of each cylinder 30 via an exhaust valve 38. The intake passage 35 is provided with an air flow meter 75, a pressure sensor 76, and a throttle valve 40 that adjusts the amount of intake air. The exhaust passage 37 is provided with a catalyst 43 for purifying exhaust gas.

Each cylinder 30 is provided with an in-cylinder injection valve 41. The in-cylinder injection valve 41 injects fuel directly into the cylinder 30. Note that instead of or in addition to the in-cylinder injection valve 41, a port injection valve that injects fuel toward the intake port may be provided. Each cylinder 30 is provided with an ignition plug 42 that ignites the mixture of intake air introduced through the intake passage 35 and fuel injected by the in-cylinder injection valve 41 by spark discharge.

[Crank angle detection structure]
3A is an explanatory diagram of a structure for detecting a crank angle. The crank angle sensor 72 outputs a signal corresponding to a change in the rotation angle of the crankshaft 33 of the engine 10. The crank rotor 34 is fixed to the crankshaft 33. The crank angle sensor 72 is a magnetic resistance element type sensor that is composed of a sensor circuit incorporating a magnet and a magnetic resistance element, and generates a pulse signal when a magnetic vector acting on the magnetic resistance element changes due to the rotation of the crank rotor 34.

The crank rotor 34 has a plurality of protrusions 341 formed on its outer circumference at intervals of 10° CA in the circumferential direction, and has a missing tooth portion 342 where a protrusion 341 is missing at one point on the outer circumference. This missing tooth portion 342 has a width of two protrusions (a width of 30° CA). The crank angle sensor 72 outputs a pulse signal in response to the passage of the plurality of protrusions 341 of the crank rotor 34, which rotates integrally with the crankshaft 33. The ECU 100 calculates the crank angle by counting the pulse signals. In addition, when a pulse signal is output after a pulse signal has not been output for a period of two output intervals, the ECU 100 detects the missing tooth portion 342 based on the pulse signal. The ECU 100 updates the calculated crank angle to the crank angle value that should be calculated when the missing tooth portion 342 is detected. In this way, the ECU 100 calculates the crank angle and calculates the engine speed, which indicates the rotational speed of the crankshaft 33 per unit time.

Figure 3B is an explanatory diagram of the pulse signal output by the crank angle sensor 72. In this embodiment, the crank angle sensor 72 outputs a pulse signal corresponding to the protrusion 341 of the crank rotor 34 every time the crankshaft 33 rotates 10° CA. In addition, 70° CA, 80° CA, and although not shown, 430° CA and 440° CA correspond to the missing tooth portion 342 of the crank rotor 34, and the crank angle sensor 72 does not output a pulse signal in this range. Note that the range and number of the missing tooth portion 342 are not limited to this.

[Maximum motor torque and torque required for cranking]
FIG. 4 is a map showing the relationship between the torque and the rotation speed of the motor 15. The vertical axis indicates the torque of the motor 15, and the horizontal axis indicates the rotation speed of the motor 15. The solid line in FIG. 4 indicates the maximum torque that the motor 15 can output. When the rotation speed of the motor 15 is low, the maximum torque is high, and as the rotation speed of the motor 15 increases, the maximum torque decreases. Here, the motor 15 must always secure the torque required for cranking the engine 10 described above as surplus torque. For this reason, the operating range in which the vehicle can run in the motor mode is the range obtained by dividing the torque required for cranking from the maximum torque.

The wider the driving range in the motor mode, the more the frequency of engine 10 operation can be reduced, improving fuel efficiency. For this reason, it is preferable that the torque required for cranking is as low as possible without affecting the startability of engine 10. When cranking engine 10, motor 15 needs to output a torque that is sufficient to overcome the rotational resistance torque that acts as a resistance to the rotation of engine 10. The rotational resistance torque of engine 10 varies depending on the crank angle when engine 10 is stopped. In this embodiment, ECU 100 starts engine 10 by having motor 15 output a torque that corresponds to the crank angle when engine 10 is stopped. This will be explained in detail below.

[Engine start control]
5 is a flowchart showing an example of engine start control executed by the ECU 100. This control is executed when the ignition is on. The ECU 100 determines whether or not the rotation of the engine 10 has stopped based on a pulse signal from the crank angle sensor 72 (step S1). If the answer is No in step S1, the control ends. If the answer is Yes in step S1, the ECU 100 determines whether or not there is a request to start the engine 10 (step S2). If the answer is No in step S2, the control ends. If the answer is No in step S2, the control ends.

Next, the ECU 100 acquires the first to third angles based on the crank angle sensor 72 (step S3). The first angle is the crank angle detected by the crank angle sensor 72 when the engine 10 is stopped. The second angle is the crank angle that can be detected by the crank angle sensor 72 within a predetermined range in the forward rotation direction of the engine 10 from the first angle. The third angle is the crank angle that can be detected by the crank angle sensor 72 within a predetermined range in the reverse rotation direction of the engine 10 from the first angle. In this embodiment, the second angle indicates the angle detected by the crank angle sensor 72 next to the first angle when the engine 10 rotates forward from the first angle. The third angle is the crank angle detected by the crank angle sensor 72 immediately before the first angle is detected. In other words, the second and third angles are crank angles that can be detected by the crank angle sensor 72 and are crank angles before and after the first angle.

For example, as shown in FIG. 3B, when the first angle is 50° CA, the second and third angles are 60° CA and 40° CA, respectively. When the first angle is 60° CA, the second and third angles are 90° CA and 50° CA, respectively. When the first angle is 90° CA, the second and third angles are 100° CA and 60° CA, respectively. Step S3 is an example of a process executed by the crank angle acquisition unit.

Next, the ECU 100 acquires the intake manifold pressure based on the pressure sensor 76 (step S4). Step S5 is an example of processing executed by the pressure acquisition unit. Next, the ECU 100 calculates the elapsed time since the engine 10 was stopped (step S5).

Next, the ECU 100 calculates the first to third required torques by referring to the map in FIG. 6 based on the above-mentioned first to third angles, the intake manifold pressure, and the time elapsed since the engine 10 stopped rotating (step S6). FIG. 6 is an example of a map that specifies the required torque required to crank the engine 10 according to the crank angle when the engine 10 is stopped. In the map in FIG. 6, the vertical axis indicates the required torque, and the horizontal axis indicates the crank angle. Therefore, the first to third required torques are torques required to crank the engine 10 when the crank angle when the engine 10 stopped rotating is the first to third angles.

The map in Figure 6 shows the required torque corresponding to the intake stroke top dead center (0°CA) to the vicinity of the compression stroke top dead center (120°CA) of one of the six cylinders 30. Therefore, in the actual map, the required torque from 0°CA to 110°CA is set to approximately the same value as the required torque in each of the following sections: 120°CA to 230°CA, 240°CA to 350°CA, 360°CA to 470°CA, 480°CA to 590°CA, and 600°CA to 710°CA. As mentioned above, 70°CA, 80°CA, 430°CA, and 440°CA correspond to the missing tooth portion 342, so the torque is not determined in these sections.

Figure 6 shows the torque required when the intake manifold pressure is high and low immediately after the engine 10 stops rotating, and the torque required when the in-cylinder pressure becomes atmospheric pressure a predetermined time after the engine 10 stops rotating. These required torques are adaptive values calculated from experimental results.

As shown in FIG. 6, immediately after the engine 10 stops rotating, the required torque is constant regardless of the crank angle at the time of stopping. This is because the in-cylinder pressure is still high immediately after the engine stops rotating, and the compression torque that acts as a resistance to the rotation of the engine 10 during cranking is also high, so a large torque is required to crank the engine regardless of the crank angle at the time of stopping. Also, as shown in the map in FIG. 6, when the intake manifold pressure is high immediately after the engine 10 stops rotating, the required torque is set to a higher value than when the intake manifold pressure is low. This is because when the intake manifold pressure is high immediately after the engine stops rotating, the in-cylinder pressure is higher than when the intake manifold pressure is low, and the compression torque of the engine 10 is also higher.

After the engine 10 stops rotating, air in the cylinder starts to leak from the gap between the piston ring and the bore wall, gradually lowering the cylinder pressure, and after a certain time has passed since the engine 10 stopped rotating, the cylinder pressure is maintained at atmospheric pressure. In this case, the compression torque also decreases, so the required torque is lower than the required torque immediately after the engine 10 stopped rotating. In addition, the compression torque in this case varies greatly depending on the volume of the cylinder that has reached atmospheric pressure, in other words, the crank angle. For this reason, as shown in FIG. 6, the required torque varies depending on the crank angle when the engine 10 stops rotating. In this case, the required torque is minimum when the piston 31 is at bottom dead center (60° CA) and maximum at top dead center.

For example, immediately after rotation has stopped, the ECU 100 calculates the first to third required torques as all being the same value according to the intake manifold pressure immediately after rotation has stopped, as shown in FIG. 6. After a predetermined time has elapsed since rotation has stopped, the ECU 100 calculates the first to third required torques based on the torque required when the in-cylinder pressure becomes atmospheric pressure after the predetermined time has elapsed since rotation has stopped.

Before a predetermined time has elapsed since the rotation has stopped, the ECU 100 calculates the first to third required torques, for example, as follows. The ECU 100 calculates the difference between the required torque immediately after the rotation has stopped, which is determined according to the intake manifold pressure immediately after the rotation has stopped, and the required torque when the in-cylinder pressure becomes atmospheric pressure. Next, the ratio of the actual elapsed time from the rotation stop to the predetermined time from the rotation stop until the in-cylinder pressure becomes atmospheric pressure is calculated. Next, the above-mentioned difference is multiplied by the ratio. The value obtained in this way corresponds to the decrease in the required torque over the elapsed time from the rotation stop. Therefore, the value obtained by subtracting this value from the required torque immediately after the rotation has stopped is calculated as the final required torque. The first to third required torques can be calculated by performing the above calculations for each of the first to third angles. In this case, it is assumed that the in-cylinder pressure becomes atmospheric pressure after a predetermined time has elapsed since the rotation has stopped, regardless of the intake manifold pressure immediately after the rotation has stopped. Step S6 is an example of a process executed by the calculation unit.

Next, the ECU 100 selects the maximum value of the first to third required torques as the required torque (step S7), and executes start control to start the engine 10 (step S8). In the start control, cranking of the engine 10 is started by slipping the K0 clutch 14 and outputting the required torque from the motor 15, and then combustion is started from the cylinder 30 that is scheduled to pass the compression top dead center for the first time, and the K0 clutch 14 is engaged. This starts the engine 10. Step S7 is an example of a process executed by the selection unit. Step S8 is an example of a process executed by the start control unit.

The reason for selecting the maximum value of the first to third required torques as the required torque is as follows. As described above, the detection resolution of the crank angle sensor 72 is 10° CA excluding the toothless portion 342. Therefore, the actual crank angle when the rotation stops is between the first angle and the second angle described above, and it is not possible to determine whether the crank angle is closer to the first or second angle. In addition, due to the repulsive force caused by the compression torque, the piston 31 of the cylinder 30 in the compression stroke may not pass the top dead center, and the engine 10 may rotate in reverse just before the rotation stops. In this case, the actual crank angle when the rotation stops is between the first angle and the third angle described above, and it is not possible to determine whether the crank angle is closer to the first or third angle. Therefore, by selecting the maximum value of the first to third required torques as the required torque, it is possible to prevent the startability of the engine 10 from being reduced due to a lack of torque required for cranking.

The selection range of the required torque is limited to the first required torque corresponding to the first angle, as described above, and the second and third required torques corresponding to the second and third angles before and after the first angle, respectively. For example, if the selection range of the required torque is too wide, the required torque selected as the required torque may be excessive relative to the torque actually required for cranking. By limiting the selection range of the required torque as in this embodiment, it is possible to prevent the required torque from being excessive relative to the torque actually required for cranking. This reduces the required torque for the motor 15 during cranking, making it possible to ensure a driving range in the motor mode, and thereby improving fuel efficiency by suppressing the driving frequency of the engine 10.

Also, as shown in FIG. 6, from after the engine 10 is stopped until the cylinder pressure becomes atmospheric pressure, the higher the intake manifold pressure immediately after stopping, the larger the first to third required torques are calculated to be. Therefore, it is possible to prevent a shortage of torque required for cranking by taking into account the magnitude of the compression torque.

Also, as shown in FIG. 6, from when the engine 10 is stopped until the cylinder pressure becomes atmospheric pressure, the longer the time that has elapsed since the engine was stopped, the smaller the first to third required torques are calculated to be. This makes it possible to prevent the torque required for cranking from becoming too large compared to the compression torque, which decreases as the elapsed time increases.

In addition, if the crank angle detected when the rotation stops corresponds to the toothless portion 342, the larger of the first and second required torques may be selected as the required torque without calculating the third required torque. For example, in this embodiment, if the crank angle detected when the rotation stops is 60° CA, the larger of the first and second required torques corresponding to the first angle 60° CA and the second angle 90° CA may be selected as the required torque. The reason for this is as follows. Even if the engine 10 rotates in reverse just before the rotation stops, it only rotates in reverse by about 10° CA, whereas the toothless portion 342 corresponds to 30° CA. Therefore, even if the engine 10 rotates in reverse just before the rotation stops, the crank angle at the time when the engine 10 actually stops is likely to be within this 30° CA range.

If the crank angle sensor 72 can detect the crank angle minus the amount of reverse rotation even when the engine 10 rotates in reverse, the larger of the first and second required torques may be selected as the required torque without calculating the third required torque. This is because the crank angle detected by the crank angle sensor 72 when the engine 10 stops after reverse rotation corresponds to the first angle, and therefore the third required torque corresponding to the third angle is not required.

In the above embodiment, the detection resolution of the crank angle sensor 72 is 10° CA, but is not limited to this. In addition, since the engine 10 is a six-cylinder engine, the required torque repeats approximately the same transition every 120° CA from 0° CA to 720° CA. For example, in the case of a four-cylinder engine, the required torque repeats approximately the same transition every 180° CA from 0° CA to 720° CA. In the case of an eight-cylinder engine, the required torque repeats approximately the same transition every 90° CA from 0° CA to 720° CA.

In the above embodiment, the second and third angles are described as crank angles before and after the first angle detectable by the crank angle sensor 72, but are not limited to this. For example, the second and third angles detectable by the crank angle sensor 72 within a predetermined range in which the difference in required torque from the first angle is not too large may be obtained, and the second and third required torques corresponding to the second and third angles, respectively, may be calculated. Specifically, if the detection resolution of the crank angle sensor 72 is higher than the above-mentioned 10° CA (for example, 5° CA), the second and third angles are not necessarily limited to angles before and after the first angle, and for example, the second angle may be the second angle detectable by the crank angle sensor 72 in the forward rotation direction of the engine 10 from the first angle. The same applies to the third angle.

In the above embodiment, a hybrid vehicle is controlled by a single ECU 100, but this is not limited to the above. For example, the above-mentioned control may be performed by multiple ECUs, such as an engine ECU that controls the engine 10, a motor ECU that controls the motor 15, and a clutch ECU that controls the K0 clutch 14.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

1 Hybrid vehicle 10 Engine 14 K0 clutch (clutch)
15 Motor 72 Crank angle sensor 100 ECU (start control unit, crank angle acquisition unit, calculation unit, selection unit, pressure acquisition unit)

Claims (4)

A control device for a hybrid vehicle having an engine, a motor provided on a power transmission path between the engine and drive wheels, a clutch provided on the power transmission path between the engine and the motor, and a crank angle sensor for detecting a crank angle of the engine,
a start control unit that starts the engine when there is a request to start the stopped engine by causing the motor to output a required torque required to crank the engine via the clutch;
a crank angle acquisition unit that acquires a first angle detected by the crank angle sensor when the engine is stopped and a second angle detected by the crank angle sensor next to the first angle when the engine rotates in a forward rotation direction from the first angle;
a calculation unit that calculates a first required torque and a second required torque that are required to crank the engine when the crank angle at the time when the engine is stopped is the first angle and the second angle, respectively;
a selection unit that selects the larger of the first and second required torques as the required torque. The crank angle acquisition unit further acquires a third angle detected immediately before the first angle is detected by the crank angle sensor ,
the calculation unit further calculates a third required torque that is required to crank the engine when the crank angle is the third angle at the time when the engine is stopped;
2. The control device for a hybrid vehicle according to claim 1, wherein the selection unit selects a maximum value from among the first, second, and third required torques as the required torque. a pressure acquiring unit that acquires a pressure in an intake passage downstream of a throttle valve of the engine,
3. The control device for a hybrid vehicle according to claim 1, wherein the calculation unit calculates the first and second required torques to be greater as the pressure increases. 4. The control device for a hybrid vehicle according to claim 1, wherein the calculation unit calculates the first and second required torques to be smaller as an elapsed time since the engine was stopped is longer.

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