Control device for hybrid vehicle

Abstract

To provide a controller for a hybrid vehicle, capable of ensuring the startability of an engine.SOLUTION: A controller for a hybrid vehicle which includes a motor provided on a power transmission path between an engine and a drive wheel, a clutch provided between the engine and the motor, and a crank angle sensor, includes: a start control section for starting the engine by allowing the motor to output a required torque required for cranking the engine when the start of the stopped engine is requested; a crank angle acquisition section for acquiring a first angle during the stop of the engine and a second angle which can be detected within a prescribed range in an engine normal rotation direction from the first angle; a calculation section for calculating first and second necessary torques needed for cranking the engine when crank angles during the stop of the engine are the first and second angles, respectively; and a selection section for selecting the greater one of the first and second necessary torques as the required torque.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] There is known a hybrid vehicle having an engine, a motor provided on a power transmission path between the engine and drive wheels, a clutch provided between the engine and the motor on the power transmission path, and a crank angle sensor for detecting a crank angle of the engine. In such a hybrid vehicle, when there is a start request for the stopped engine, the motor outputs a required torque required to crank the engine via the clutch, thereby starting the engine (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The torque required to crank the engine varies depending on the crank angle at the time of engine stop. Therefore, it is conceivable to change the torque output by the motor according to the crank angle at the time of engine stop. However, there are certain limitations to the detection resolution of the crank angle sensor that detects the crank angle. For this reason, there is a difference between the crank angle detected by the crank angle sensor at the time of engine stop and the actual crank angle at the time of engine stop, and there is a possibility that the starting performance of the engine may deteriorate due to insufficient torque for cranking.

[0005] Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that ensures the starting performance of the engine.

Means for Solving the Problems

[0006] The above object is 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 between the engine and the motor on the power transmission path, and a crank angle sensor for detecting a crank angle of the engine. When there is a start request for the stopped engine, a start control unit that starts the engine by outputting, by the motor, a required torque required to crank the engine via the clutch, a first angle detected by the crank angle sensor when the engine stops, and the positive rotation direction of the engine from the first angle when rotated to by the crank angle sensor next to the first angle detecting is made a second angle, and a crank angle acquisition unit that acquires the second angle, a calculation unit that calculates first and second required torques respectively required to crank the engine when the crank angle at the time of stopping of the engine is the first and second angles, and a selection unit that selects the larger of the first and second required torques as the required torque. It can be achieved by a control device for a hybrid vehicle provided with.

[0007] The crank angle acquisition unit immediately before the first angle is detected by the crank angle sensor further acquires a third angle, the calculation unit further calculates a third required torque required to crank the engine when the crank angle is the third angle at the time of stopping of the engine, and the selection unit selects the maximum value among the first, second, and third required torques as the required torque. It may be selected.

[0008] A pressure acquisition unit that acquires the pressure in the intake passage on the downstream side of the throttle valve of the engine is provided, and the calculation unit may calculate the first and second required torques larger as the pressure is higher.

[0009] The calculation unit may calculate the first and second required torques smaller as the elapsed time since the engine stopped is longer. [Advantages of the Invention]

[0010] According to the present invention, it is possible to provide a control device for a hybrid vehicle that ensures the starting performance of the engine. [Brief Description of the Drawings]

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0012] [Schematic Configuration of Hybrid Vehicle] FIG. 1 is a schematic configuration 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 sequentially provided in the power transmission path from the engine 10 to the drive wheels 13. The engine 10 and the motor 15 are mounted as driving power sources for the hybrid vehicle 1. The engine 10 is, for example, a V-type 6-cylinder gasoline engine, but the number of cylinders is not limited to this, and it 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 the transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a differential 12.

[0013] The K0 clutch 14 is provided between the engine 10 and the motor 15 on the same power transmission path. The K0 clutch 14 receives hydraulic pressure supply from the released state and becomes engaged, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 becomes released in response to the stop of the hydraulic pressure supply, interrupting the power transmission between the engine 10 and the motor 15. The engaged state means that both engaging elements of the K0 clutch 14 are connected and the engine 10 and the motor 15 have the same rotational speed. The released state means that both engaging elements of the K0 clutch 14 are separated.

[0014] 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 supply from the battery 16, and also functions as a generator that generates electric power for charging the battery 16 in response to power transmission from the engine 10 or the drive wheels 13. The electric power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

[0015] The inverter 17 is controlled by an ECU 100 described later, converts the DC voltage from the battery 16 into an AC voltage, or converts the AC voltage from the motor 15 into a DC voltage. In the case of a power running operation where the motor 15 outputs torque, the inverter 17 converts the DC voltage of the battery 16 into an AC voltage and adjusts the power supplied to the motor 15. In the case of a regenerative operation where the motor 15 generates electricity, the inverter 17 converts the AC voltage from the motor 15 into a DC voltage and adjusts the power supplied to the battery 16.

[0016] The torque converter 18 is a fluid coupling having a torque amplification function. The transmission 19 is a stepped automatic transmission that switches the gear ratio in multiple steps by switching the gear stage, but it 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 hydraulic pressure supply and engages to directly connect the motor 15 and the transmission 19.

[0017] 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, respectively. The hydraulic control mechanism 22 is provided with respective 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. Incidentally, a wet clutch may be provided instead of the torque converter 18.

[0018] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as the hybrid vehicle. The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to vehicle running control, and a memory in which control programs and data are stored. The ECU 100 is an example of a hybrid vehicle, and specifically, it functionally realizes a starting control unit, a crank angle acquisition unit, a calculation unit, a selection unit, and a pressure acquisition unit, which will be described later.

[0019] The ECU 100 controls the driving of the engine 10 and the motor 15. Specifically, the ECU 100 controls the torque and rotational 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 rotational speed and torque of the motor 15 by controlling the inverter 17 to adjust the amount of power transfer between the motor 15 and the battery 16. Also, the ECU 100 performs drive control of the K0 clutch 14, the lock-up clutch 20, and the transmission 19 through the control of the hydraulic control mechanism 22.

[0020] Signals from the ignition switch 71, the crank angle sensor 72, the motor rotational speed sensor 73, the accelerator opening sensor 74, the air flow meter 75, the pressure sensor 76, and the water temperature sensor 77 are input to the ECU 100. The crank angle sensor 72 detects the rotational speed of the crankshaft of the engine 10. The motor rotational speed sensor 73 detects the rotational 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 driver's accelerator pedal. The air flow meter 75 detects the intake air amount of the engine 10. The pressure sensor 76 detects the pressure (hereinafter referred to as the intake manifold pressure) in the intake passage 35 on the downstream side of the throttle valve 40, which will be described later. The water temperature sensor 77 detects the temperature of the cooling water of the engine 10.

[0021] The ECU 100 drives 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 on the power of the motor 15. In the hybrid mode, the ECU 100 switches the K0 clutch 14 to the engaged state and runs at least on the power of the engine 10. Note that the hybrid mode includes a mode of running on only the power of the engine 10 and a mode of running with both the engine 10 and the motor 15 as power sources by powering the motor 15.

[0022] The switching of the driving mode is performed based on the required driving force of the vehicle obtained from the vehicle speed and the accelerator opening, the state of charge of the battery 16, etc. For example, when the required driving force is relatively small and the SOC (State Of Charge) indicating the power storage amount of the battery 16 is relatively high, the motor mode with the engine 10 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 with the engine 10 driven is selected.

[0023] When a predetermined stop condition is satisfied, the ECU 100 executes intermittent operation control to automatically stop the engine 10, and when a predetermined start condition is satisfied, starts the automatically stopped engine 10. For example, when the accelerator opening becomes zero in the hybrid mode, the ECU 100 automatically stops the engine 10 as if the automatic stop condition is satisfied. Further, when the accelerator opening becomes larger than zero, for example, the ECU 100 executes start control to automatically start the engine 10 as if the start condition is satisfied. At the time of automatic stop, the ECU 100 releases the K0 clutch 14 to stop combustion. At the time of automatic start, 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.

[0024] [Schematic Configuration of Engine] Figure 2 is a schematic configuration diagram of the engine 10. The engine 10 has cylinders 30, pistons 31, connecting rods 32, a crankshaft 33, an intake passage 35, intake valves 36, an exhaust passage 37, and exhaust valves 38. Only one of the plurality of cylinders 30 of the engine 10 is shown in Figure 2. Combustion of the air-fuel mixture takes place in the cylinder 30. The piston 31 is reciprocally accommodated in each cylinder 30 and is connected to the crankshaft 33, which is the 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.

[0025] 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. An air flow meter 75, a pressure sensor 76, and a throttle valve 40 for adjusting the intake air amount are provided in the intake passage 35. A catalyst 43 for exhaust purification is provided in the exhaust passage 37.

[0026] An in-cylinder injection valve 41 is provided in the cylinder 30. The in-cylinder injection valve 41 injects fuel directly into the cylinder 30. Incidentally, instead of the in-cylinder injection valve 41 or in addition to the in-cylinder injection valve 41, a port injection valve for injecting fuel toward the intake port may be provided. Each cylinder 30 is provided with a spark plug 42 for igniting an air-fuel mixture of the intake air introduced through the intake passage 35 and the fuel injected by the in-cylinder injection valve 41 by spark discharge.

[0027] [Crank Angle Detection Structure] FIG. 3A is an explanatory diagram of a structure for detecting the 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. A crank rotor 34 is fixed to the crankshaft 33. The crank angle sensor 72 is composed of a sensor circuit incorporating a magnet and a magnetoresistive element, and is a magnetoresistive element type sensor that generates a pulse signal by changing the magnetic vector applied to the magnetoresistive element due to the rotation of the crank rotor 34.

[0028] 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 tooth missing portion 342 where the protrusion 341 is missing at one location on its outer circumference. This tooth missing portion 342 has a width corresponding to two protrusions (width for 30°CA). The crank angle sensor 72 outputs a pulse signal corresponding to the passage of the plurality of protrusions 341 of the crank rotor 34 that rotates integrally with the crankshaft 33. The ECU 100 calculates the crank angle by counting the pulse signal. Further, when the pulse signal is output after not being continuously output for a period twice the previous output interval, the ECU 100 detects the tooth missing portion 342 based on this. The ECU 100 updates the calculated crank angle to the value of the crank angle that should be calculated when the tooth missing portion 342 is detected. The ECU 100 calculates the crank angle in this way and calculates the engine speed indicating the rotational speed of the crankshaft 33 per unit time.

[0029] 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 by 10°CA. Also, 70°CA, 80°CA, and although not shown in the figure, 430°CA, 440°CA correspond to the tooth missing portion 342 of the crank rotor 34, and in this section, the crank angle sensor 72 does not output a pulse signal. Note that the range and number of the tooth missing portion 342 are not limited to this.

[0030] [Maximum Torque of the Motor and Torque Required for Cranking] Figure 4 is a map showing the relationship between the torque and rotational speed of the motor 15. The vertical axis indicates the torque of the motor 15, and the horizontal axis indicates the rotational speed of the motor 15. The solid line in Figure 4 indicates the maximum torque that the motor 15 can output. When the rotational speed of the motor 15 is low, the maximum torque is high, and as the rotational speed of the motor 15 increases, the maximum torque decreases. Here, the motor 15 needs to always ensure the torque required for cranking the above-described engine 10 as surplus torque. For this reason, the driving range in which it is possible to drive in the motor mode is the range obtained by dividing the maximum torque by the torque required for cranking.

[0031] The wider the driving range in motor mode, the more the driving frequency of the engine 10 can be suppressed, so the fuel efficiency is improved. Therefore, it is preferable that the torque required for cranking is as low as possible within a range that does not affect the starting performance of the engine 10. When cranking the engine 10, the motor 15 needs to output a torque that can overcome the rotational resistance torque that becomes the resistance of the rotation of the engine 10. The rotational resistance torque of the engine 10 varies depending on the crank angle at the time of stopping of the engine 10. In the present embodiment, the ECU 100 starts the engine 10 by causing the motor 15 to output a torque corresponding to the crank angle at the time of stopping of the engine 10 as described above. This will be described in detail below.

[0032] [Engine starting control] FIG. 5 is a flowchart showing an example of engine starting 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 the pulse signal from the crank angle sensor 72 (step S1). If the answer is No in step S1, this control ends. If the answer is Yes in step S1, the ECU 100 determines whether or not there is a starting request for the engine 10 (step S2). If the answer is No in step S2, this control ends. If the answer is No in step S2, this control ends.

[0033] 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 in a stopped state. The second angle is the crank angle detectable 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 detectable by the crank angle sensor 72 within a predetermined range in the reverse rotation direction of the engine 10 from the first angle. In the present embodiment, as the second angle, it 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. Further, as the third angle, it 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 detectable by the crank angle sensor 72 and are the crank angles before and after the first angle.

[0034] 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 the process executed by the crank angle acquisition unit.

[0035] Next, the ECU 100 acquires the intake manifold pressure based on the pressure sensor 76 (step S4). Step S5 is an example of the process executed by the pressure acquisition unit. Next, the ECU 100 calculates the elapsed time since the stop of the engine 10 (step S5).

[0036] Next, the ECU 100 calculates the first to third required torques with reference to the map in FIG. 6 based on the above-described first to third angles, the intake manifold pressure, and the elapsed time since the engine 10 stopped rotating (step S6). FIG. 6 is an example of a map defining the required torque necessary to crank the engine 10 according to the crank angle at the time of stopping of the engine 10. In the map of 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 the torques required to crank the engine 10 when the crank angle at the time of stopping of the engine 10 is the first to third angles.

[0037] The map in FIG. 6 shows the required torque corresponding from the intake top dead center (0°CA) of one of the six cylinders 30 to near the compression top dead center (120°CA). Therefore, in the actual map, the required torque from 0°CA to 110°CA is defined to be approximately the same value as the required torque in each of the intervals of 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. Since 70°CA, 80°CA, 430°CA, and 440°CA correspond to the missing teeth portion 342 as described above, the torque is not defined in this interval.

[0038] FIG. 6 shows the required torque when the intake manifold pressure is high and low immediately after the engine 10 stops rotating, and the required torque when the in-cylinder pressure becomes atmospheric pressure after a predetermined time has elapsed since the engine 10 stops rotating. These required torques are fitting values calculated based on experimental results.

[0039] 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 stop. This is because immediately after the rotation stops, the in-cylinder pressure is still high, and the compression torque that resists the rotation of the engine 10 during cranking is also high. To crank the engine, a large torque is required regardless of the crank angle at the time of stop. Also, as shown in the map of FIG. 6, when the intake manifold pressure immediately after the engine 10 stops rotating is high, the required torque is defined as a higher value than when it is low. This is because when the intake manifold pressure immediately after the rotation stops is high, the in-cylinder pressure is higher and the compression torque of the engine 10 is also higher than when it is low.

[0040] Also, after the engine 10 stops rotating, air in the cylinder starts to leak from the gap between the piston ring and the bore wall, and the in-cylinder pressure gradually decreases. After a predetermined time has elapsed since the rotation stopped, the in-cylinder pressure is maintained at atmospheric pressure. In this case, since the compression torque also decreases, the required torque becomes a lower value than the required torque immediately after the rotation stops. Also, the compression torque in this case varies greatly depending on the size of the volume in the cylinder that has reached atmospheric pressure, in other words, depending on the crank angle. For this reason, as shown in FIG. 6, the required torque varies depending on the crank angle at the time of rotation stop. In this case, the required torque is minimum when the piston 31 is at the bottom dead center (60°CA) and maximum at the top dead center.

[0041] For example, as shown in FIG. 6, immediately after the rotation stops, the ECU 100 calculates the first to third required torques as all the same value according to the intake manifold pressure immediately after the rotation stops. Also, after a predetermined time has elapsed since the rotation stopped, the ECU 100 calculates the first to third required torques based on the required torque when the in-cylinder pressure has reached atmospheric pressure after a predetermined time has elapsed since the rotation stopped.

[0042] Also, before a predetermined time elapses since the rotation stop, the ECU 100 calculates the first to third required torques as follows, for example. It calculates the difference between the required torque immediately after the rotation stop, which is determined according to the intake manifold pressure immediately after the rotation stop, and the required torque when the in-cylinder pressure becomes atmospheric pressure. Next, it calculates the ratio of the elapsed time from the actual rotation stop to the predetermined time until the in-cylinder pressure becomes atmospheric pressure since the rotation stop. Next, it multiplies the above-described difference by the ratio. The value obtained in this way corresponds to the decrease in the required torque over the elapsed time since the rotation stop. Therefore, the value obtained by subtracting this value from the required torque immediately after the rotation stop is calculated as the final required torque. By performing the above calculations for each of the first to third angles, the first to third required torques can be calculated. In this case, it is assumed that the in-cylinder pressure becomes atmospheric pressure after a predetermined time elapses since the rotation stop, regardless of the intake manifold pressure immediately after the rotation stop. Step S6 is an example of the process executed by the calculation unit.

[0043] Next, the ECU 100 selects the maximum value among the first to third required torques as the required torque (step S7), and executes start control for starting the engine 10 (step S8). In the start control, the K0 clutch 14 is slipped to output the required torque from the motor 15 to start cranking the engine 10, and then combustion is started from the cylinder 30 that is planned to exceed top dead center of compression for the first time, and the K0 clutch 14 is engaged. Thereby, the engine 10 starts. Step S7 is an example of the process executed by the selection unit. Step S8 is an example of the process executed by the start control unit.

[0044] Thus, the reason for selecting the maximum value among 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 except for the tooth missing portion 342. For this reason, the actual crank angle at the time of rotation stop is located between the first angle and the second angle described above, and it is impossible to determine which of the first and second angles it is closer to. Further, due to the repulsive force caused by the compression torque, the piston 31 of the cylinder 30 in the compression stroke may not exceed the top dead center and the engine 10 may rotate reversely immediately before the rotation stops. In this case, the actual crank angle at the time of rotation stop is located between the first angle and the third angle described above, and it is impossible to determine which of the first and third angles it is closer to. Therefore, by selecting the maximum value from the first to third required torques as the required torque, it is possible to suppress the reduction of the starting performance of the engine 10 due to insufficient torque required for cranking.

[0045] Also, the selection range of the required torque is limited to the first required torque corresponding to the first angle and the second and third required torques corresponding to the second and third angles before and after the first angle, respectively, as described above. For example, if the selection range of the required torque is too wide, the required torque selected as the required torque may be excessive with respect to the torque actually required for cranking. By limiting the selection range of the required torque as in this embodiment, it is possible to avoid the required torque from becoming excessive with respect to the torque actually required for cranking. As a result, the required torque on the motor 15 during cranking can be reduced, a driving region in the motor mode can be secured, and the driving frequency of the engine 10 can be suppressed to improve the fuel efficiency.

[0046] Also, as shown in FIG. 6, from after the engine 10 stops until the in-cylinder pressure becomes atmospheric pressure, the higher the in-manifold pressure immediately after the stop, the larger the values of the first to third required torques are calculated. For this reason, it is possible to suppress the shortage of the torque required for cranking in consideration of the magnitude of the compression torque.

[0047] Further, as shown in FIG. 6, from after the engine 10 stops until the in-cylinder pressure becomes atmospheric pressure, the longer the elapsed time since the stop, the smaller the first to third required torques are calculated. Therefore, it is possible to prevent the torque required for cranking from becoming excessively large with respect to the compression torque that decreases as the elapsed time becomes longer.

[0048] In addition, when the crank angle detected at the time of rotation stop corresponds to the missing tooth portion 342, instead of calculating the third required torque, the larger one of the first and second required torques may be selected as the required torque. For example, in this embodiment, when the crank angle detected at the time of rotation stop is 60°CA, the larger one of the first and second required torques corresponding to 60°CA which is the first angle and 90°CA which is the second angle may be selected as the required torque. The reason for this is as follows. Even if the engine 10 rotates reversely immediately before the rotation stop, it rotates reversely only about 10°CA, whereas 30°CA corresponds to the missing tooth portion 342. Therefore, even when the engine 10 rotates reversely immediately before the rotation stop, the crank angle at the actual stop of the engine 10 is likely to be within this 30°CA range.

[0049] When the crank angle sensor 72 can detect the crank angle with the reverse rotation component subtracted even when the engine 10 rotates reversely, instead of calculating the third required torque, the larger one of the first and second required torques may be selected as the required torque. This is because the third required torque corresponding to the third angle becomes unnecessary since the crank angle detected by the crank angle sensor 72 at the time of stop after reverse rotation corresponds to the first angle.

[0050] In the above embodiment, the detection resolution of the crank angle sensor 72 is 10°CA, but it is not limited to this. Further, since the engine 10 is a six-cylinder engine, the required torque repeats substantially 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 substantially the same transition every 180°CA from 0°CA to 720°CA. In the case of an eight-cylinder engine, the required torque repeats substantially the same transition every 90°CA from 0°CA to 720°CA.

[0051] In the above embodiment, as the second and third angles, the crank angles before and after the first angle detectable by the crank angle sensor 72 are described as an example, but the present invention is not limited thereto. For example, the second and third angles detectable by the crank angle sensor 72 within a predetermined range where the difference in required torque does not become too large from the first angle may be acquired, and the second and third required torques corresponding to the second and third angles may be calculated respectively. Specifically, when the detection resolution of the crank angle sensor 72 is higher than the above-described 10°CA (for example, 5°CA), the second and third angles are not necessarily limited to the angles before and after the first angle. 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.

[0052] In the above embodiment, the case where a hybrid vehicle is controlled by a single ECU 100 is illustrated, but the present invention is not limited thereto. For example, the above-described control may be executed by a plurality of 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.

[0053] As described above in detail with respect to the embodiments of the present invention, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0054] 1 Hybrid vehicle 10 Engine 14 K0 clutch (clutch) 15 Motor 72 Crank angle sensor 100 ECU (starting control unit, crank angle acquisition unit, calculation unit, and selection unit, pressure acquisition unit)

Claims

1. In 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 between the engine and the motor on the power transmission path, and a crank angle sensor for detecting a crank angle of the engine, a starting control unit that starts the engine by outputting, by the motor, a required torque required to crank the engine via the clutch when there is a starting request for the stopped engine; a crank angle acquisition unit that acquires a first angle detected by the crank angle sensor when the engine stops, and a second angle that is detected next to the first angle by the crank angle sensor when the engine rotates in the normal rotation direction from the first angle; a calculation unit that calculates a first required torque and a second required torque required to crank the engine when the crank angle at the time of engine stop 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. A control device for a hybrid vehicle comprising the same.

2. 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 required to crank the engine when the crank angle at the time of engine stop is the third angle, and the selection unit selects the maximum value among the first, second, and third required torques as the required torque. The control device for a hybrid vehicle according to Claim 1.

3. comprising a pressure acquisition unit that acquires a pressure in an intake passage downstream of a throttle valve of the engine, wherein the calculation unit calculates the first and second required torques to be larger as the pressure is higher. The control device for a hybrid vehicle according to Claim 1 or 2.

4. The calculation unit calculates the first and second required torques to be smaller as the elapsed time since the engine stopped is longer. The control device for a hybrid vehicle according to any one of Claims 1 to 3.

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