Hybrid vehicle control device

Abstract

To provide a hybrid-vehicular control apparatus with the occurrence of a shock suppressed.SOLUTION: In a hybrid-vehicular control apparatus, in a case where a motor is being in motion, a clutch disengaged, and an engine required to start, the clutch is shifted to be engaged while a throttle opening degree is being controlled at an engine-start opening level, and the engine is started by cranking with a motor. The control apparatus includes: a torque control part for controlling toque of the motor and that of the engine so as to increase a distribution ratio of the engine while decreasing that of the motor with respect to a load of a transmission, after starting the engine; and a throttle control part for controlling a throttle opening degree at an engine-start opening level in a case where the distribution ratio of the engine is equal to or less than a threshold, and controlling the throttle opening degree at an idling maintaining opening level for maintaining an engine revolution speed at a target idling speed in a case where the distribution ratio of the engine exceeds the threshold.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] A control device for a hybrid vehicle provided with a clutch, a motor, and a transmission provided in order on the power transmission path from the engine to the wheels is known. When the motor is driving and the clutch is in the released state and there is a request to start the engine, such a control device starts the engine by cranking the engine with the motor by shifting the clutch to the engaged state (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] When starting such an engine, it is conceivable to control the throttle opening of the engine to the starting opening, and after starting the engine, control the throttle opening to the idle maintenance opening at which the engine speed maintains the target idle speed. However, depending on the timing of switching the throttle opening from the starting opening to the idle maintenance opening, the engine torque may increase and the vehicle may be shocked.

[0005] Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that suppresses the occurrence of shock.

Means for Solving the Problems

[0006] In a control device for a hybrid vehicle in which a clutch, a motor, and a transmission are provided in order on a power transmission path from an engine to wheels, when the motor is in operation, the clutch is in a released state, and there is a starting request for the engine, while controlling the throttle opening degree of the engine to a starting opening degree, the clutch is shifted to an engaged state, and the motor cranks the engine to start the engine, a starting control unit; and after the engine is started after the clutch is engaged wherein, while reducing the sharing ratio of the motor with respect to the load of the transmission and increasing the sharing ratio of the engine with respect to the load, a torque control unit that controls the respective torques of the motor and the engine; and when the sharing ratio of the engine is equal to or less than a threshold value, the throttle opening degree of the engine is controlled to the starting opening degree, and when the sharing ratio of the engine exceeds the threshold value, the throttle opening degree is controlled to an idle maintenance opening degree at which the engine speed maintains a target idle speed, a throttle control unit, are provided the idle maintenance opening degree is larger than the starting opening degree, the starting opening degree is an opening degree set in consideration of the load of the engine when the sharing ratio of the engine is 0%, and the threshold value is a parameter related to the torque of the engine other than the throttle opening degree of the engine in a state where the throttle opening degree of the engine is maintained at the starting opening degree. It is the sharing ratio of the engine corresponding to the amount of torque of the engine that can be increased by adjusting, and is set to a value greater than 0% and less than 50%. When the sharing ratio of the engine is less than or equal to the threshold value, the torque control unit controls the torque of the engine so that the sharing ratio of the engine increases by adjusting the parameter while the throttle opening degree of the engine is maintained at the starting opening degree. It can be achieved by a control device for a hybrid vehicle.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a control device for a hybrid vehicle that suppresses the generation of shock.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0009] [Schematic Configuration of Hybrid Vehicle] FIG. 1 is a schematic configuration diagram of a hybrid vehicle 1. In the power transmission path from an engine 10 to wheels 13 of the hybrid vehicle 1, a K0 clutch 14, a motor 15, and a transmission 18 are provided in this order. The engine 10 and the motor 15 are mounted as driving sources for the hybrid vehicle 1 to travel. 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, and the transmission 18 are provided in a transmission unit 11. The transmission unit 11 and the left and right wheels 13 are drivingly connected via a differential 12. The transmission 18 includes a torque converter 19 and a transmission 20.

[0010] 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 a slip state and an engaged state to connect the power transmission between the engine 10 and the motor 15. The K0 clutch 14 becomes the released state in response to the stop of the hydraulic pressure supply to cut off the power transmission between the engine 10 and the motor 15. The engaged state means 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 rotational speed. The slip state means a state in which both engagement elements of the K0 clutch 14 have a predetermined rotational speed difference and are slipping. The released state means a state in which both engagement elements of the K0 clutch 14 are separated.

[0011] The motor 15 is connected to the battery 16 via an inverter 17. The motor 15 functions as a motor that generates a driving force for the vehicle in response to power supply from the battery 16, and further functions as a generator that generates electric power for charging the battery 16 in response to power transmission from the engine 10 or the wheels 13. The electric power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

[0012] The inverter 17 is controlled by the ECU 100 described later, and 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 in which 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 in which 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.

[0013] The torque converter 19 is a fluid coupling having a torque amplification function. The transmission 20 is a stepped automatic transmission that switches the gear ratio in multiple steps by switching the gear stage, but is not limited to this and may be a continuously variable transmission. The transmission 20 is provided between the motor 15 and the wheels 13 on the power transmission path. The motor 15 and the transmission 20 are connected via the torque converter 19. The torque converter 19 is provided with a lock-up clutch 19a that receives the supply of hydraulic pressure and engages to directly connect the motor 15 and the transmission 20. Note that the torque converter 19 is not necessarily essential and may not be provided.

[0014] 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 19, the transmission 20, and the lock-up clutch 19a 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 19, the transmission 20, and the lock-up clutch 19a, and various hydraulic control valves for controlling their operating hydraulic pressures.

[0015] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a control device for the vehicle. The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, and a memory in which control programs and data are stored. The ECU 100 is an example of a control device for a hybrid vehicle, and functionally realizes a start control unit, a torque control unit, and a throttle control unit, which will be described in detail later.

[0016] 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 degree, ignition timing, and fuel injection amount of the engine 10. The ECU 100 controls the torque and rotational speed of the motor 15 by controlling the inverter 17 to adjust the amount of power transfer between the motor 15 and the battery 16. Further, the ECU 100 performs drive control of the K0 clutch 14, the lock-up clutch 19a, and the transmission 20 through the control of the hydraulic control mechanism 22.

[0017] Signals from an ignition switch 71, a crank angle sensor 72, a motor rotational speed sensor 73, an accelerator opening sensor 74, and an air flow meter 75 are input to the ECU 100. The crank angle sensor 72 detects the rotational speed of the crankshaft of the engine 10, that is, the engine rotational speed. The motor rotational speed sensor 73 detects the rotational speed of the output shaft of the motor 15, that is, the motor rotational speed. The accelerator opening sensor 74 detects the accelerator pedal opening degree, 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.

[0018] The ECU 100 drives the hybrid vehicle in either a motor mode or a hybrid mode. In the motor mode, the ECU 100 disengages 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 the power of only 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.

[0019] 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 charge 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 driving is selected.

[0020] [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 the connecting rod 32. The connecting rod 32 converts the reciprocating motion of the piston 31 into the rotational motion of the crankshaft 33.

[0021] The intake passage 35 is connected to the intake port 35p of each cylinder 30 via an intake valve 36. The exhaust passage 37 is connected to the exhaust port 37p of each cylinder 30 via an exhaust valve 38. The intake passage 35 is provided with the air flow meter 75 described above and a throttle valve 40 for adjusting the intake air amount. The exhaust passage 37 is provided with a catalyst 43 for exhaust purification.

[0022] The cylinder 30 is provided with an in-cylinder injection valve 41. 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 35p may be provided. Each cylinder 30 is provided with an ignition device 42 for igniting the 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.

[0023] [Switching Control from Motor Mode to Hybrid Mode] There may be a case where the driving mode is required to be switched from the motor mode to the hybrid mode. In this case, the engine 10 is required to be started with the motor 15 being driven. The ECU 100 starts the engine 10 by cranking the engine 10 with the motor 15 by shifting the K0 clutch 14 from the released state to the engaged state. Thereby, the engine 10 can be started while driving with the motor 15, and the driving mode can be switched from the motor mode to the hybrid mode.

[0024] [T / M Load Sharing Ratio after Engine Start] After the engine 10 is started in this way, the transfer of the sharing ratio of the T / M load is performed. The T / M load is the load of the transmission 18 that resists the rotation of the engine 10 and the motor 15. When the driving mode is the motor mode, the K0 clutch 14 is released and the engine 10 is also stopped. Therefore, the sharing ratio of the T / M load by the motor 15 (hereinafter referred to as the motor sharing ratio) is 100%, and the sharing ratio of the T / M load by the engine 10 (hereinafter referred to as the engine sharing ratio) is 0%. In the hybrid mode after the engine is started, sharing ratio transfer control for transferring the motor sharing ratio to the engine sharing ratio is performed.

[0025] In the sharing ratio transfer control, while always maintaining the total of the engine sharing ratio and the motor sharing ratio at 100%, the motor sharing ratio is gradually decreased to 0%, and the engine sharing ratio is gradually increased to 100% to calculate both sharing ratios. The ECU 100 controls the respective torques of the engine 10 and the motor 15 according to the engine sharing ratio and the motor sharing ratio. The ECU 100 controls the engine torque by controlling the ignition timing and throttle opening of the engine 10. Further, the ECU 100 controls the motor torque by controlling the inverter 17 to control the amount of power supplied from the battery 16 to the motor 15. Finally, in the hybrid mode, the engine 10 with a higher output torque than the motor 15 bears all of the T / M load, thereby improving fuel efficiency.

[0026] [Switching Control from Motor Mode to Hybrid Mode] Next, the switching control from the motor mode to the hybrid mode will be described. FIG. 3 is a timing chart showing an example of the switching control from the motor mode to the hybrid mode. FIG. 3 shows the presence or absence of an engine start request, the state of the K0 clutch 14, the T / M load sharing ratio (motor sharing ratio, engine sharing ratio) [%], motor torque [N·m], engine torque [N·m], throttle opening [deg], motor speed [rpm], and engine speed [rpm]. Note that the motor sharing ratio and the motor speed are shown by dotted lines, and the others are shown by solid lines.

[0027] When the engine speed is 0 at time t1 and there is a starting request for the engine 10 while the K0 clutch 14 is in the released state, the throttle opening is controlled to the starting opening α, and the K0 clutch 14 is controlled to a slip state to start cranking by the motor 15. The starting opening α is the throttle opening set at engine start and is a fixed value. Here, since the K0 clutch 14 is in the released state, the engine share ratio is 0%. The starting opening α is an opening set in consideration of the load on the engine 10 with such an engine share ratio of 0%, and is an opening that limits the intake air amount so that the engine speed does not increase more than necessary. The starting opening α is determined by experiments and analyses so as to ensure the starting performance of the engine 10 with the K0 clutch 14 in the released state.

[0028] After starting cranking, the motor torque increases by the amount consumed for cranking, and the engine torque and engine speed also increase. At time t2, combustion in the engine 10 starts and self-sustained operation starts, the engine torque becomes constant, and the amount of the motor torque consumed for cranking decreases. At time t3 when the engine speed further increases, the engine speed matches the motor speed and the K0 clutch 14 engages.

[0029] When the share ratio transfer control starts at time t4 thereafter, the energization amount to the motor 15 decreases and the motor torque gradually decreases, and the ignition timing of the engine 10 is corrected to the advanced side and the engine torque gradually increases. As a result, the motor share ratio gradually decreases and the engine share ratio gradually increases.

[0030] When the engine share ratio exceeds the threshold value β at time t5, the throttle opening is switched from the starting opening α to the idle maintenance opening for maintaining the engine speed at the target idle speed. The idle maintenance opening is the throttle opening that is feedback-controlled according to the deviation between the two speeds so as to maintain the engine speed at the target idle speed. Specifically, when the engine speed drops below the target idle speed, the throttle opening is controlled to increase according to the deviation, which is the amount of the engine speed drop. When the engine speed rises above the target idle speed, the throttle opening is controlled to decrease according to the deviation, which is the amount of the engine speed increase.

[0031] After time t5, the motor torque continues to decrease, and accordingly, the engine speed temporarily drops below the target idle speed. However, the throttle opening immediately increases due to the above-described feedback control. As a result, while the engine speed maintains the target idle speed, the motor torque decreases, the throttle opening increases, and the engine torque increases. When the motor share ratio becomes 0% and the engine share ratio becomes 100% at time t6, the share ratio transfer control ends, and the throttle opening becomes a substantially constant value.

[0032] For example, it is conceivable to switch the throttle opening from the starting opening α to the idle maintenance opening between time t3 and time t4 when the engine share ratio is 0% after the engine 10 starts and the K0 clutch is engaged. When the engine share ratio is 0% and the throttle opening is switched from the starting opening α to the idle maintenance opening, the engine torque may increase. Vibration caused by such an increase in engine torque may be transmitted from the engine 10 to the wheels 13, possibly causing a shock to the hybrid vehicle 1.

[0033] In this embodiment, as described above, when the engine share ratio exceeds the threshold value β, the throttle opening is switched from the starting opening α to the idle maintenance opening. Therefore, since the increase in engine torque due to the switching of the throttle opening is utilized for the engine share ratio of the T / M load, it is possible to suppress the occurrence of a shock to the hybrid vehicle 1.

[0034] As described above, when the engine sharing ratio is equal to or less than the threshold β, the throttle opening is maintained at the starting opening α, and the ignition timing is corrected toward the advanced side, thereby increasing the engine torque. Therefore, the threshold β may be a sharing ratio corresponding to the amount of engine torque that can be increased by adjusting the parameters related to the engine torque other than the throttle opening in a state where the throttle opening is maintained at the starting opening α. The adjustment of the parameters related to the engine torque other than the throttle opening is the correction toward the advanced side of the ignition timing and the increment correction of the fuel injection amount described above. For example, the threshold β is preferably set to a value greater than 0% and less than 50%. When the engine sharing ratio becomes higher than the threshold β, it is preferable to control the throttle opening to the idle maintenance opening and also control the ignition timing and the fuel injection amount to be suitable for the idle operation.

[0035] FIG. 4 is a flowchart showing an example of the switching control from the motor mode to the hybrid mode executed by the ECU 100. This control is repeatedly executed at a predetermined cycle with the ignition on. When the running mode is the motor mode, in other words, when the motor 15 is being driven and the K0 clutch 14 is in the released state, the ECU 100 determines whether there is an engine start request, that is, whether there is a request to switch to the hybrid mode (step S1). If the answer in step S1 is No, this control is terminated.

[0036] If the answer in step S1 is Yes, the ECU 100 executes engine start control (step S2). Specifically, while controlling the throttle opening to the starting opening α, the K0 clutch 14 is shifted from the released state to the engaged state, and the engine 10 is cranked and started by the motor 15. Step S2 is an example of the control executed by the start control unit.

[0037] Next, the ECU 100 starts the sharing ratio transfer control described above (step S3). Therefore, the ECU 100 calculates the engine sharing ratio and the motor sharing ratio, and controls the engine torque and the motor torque according to this sharing ratio. Step S3 is an example of the processing executed by the torque control unit.

[0038] Next, the ECU 100 determines whether the engine sharing ratio is less than or equal to the threshold value β (step S4). If Yes in step S4, the ECU 100 maintains the throttle opening at the starting opening α (step S5), and executes the process of step S4 again. If No in step S4, the ECU 100 controls the throttle opening to the idle maintenance opening (step S6). Steps S4 to S6 are an example of the control executed by the throttle control unit. As described above, when the engine sharing ratio exceeds the threshold value β, by switching the throttle opening from the starting opening α to the idle maintenance opening, it is possible to suppress the occurrence of shock in the hybrid vehicle 1.

[0039] In the above embodiment, the starting opening α is a fixed value, but it is not limited to this, and it may be a variable value that changes according to a parameter other than the engine speed, for example, the cooling water temperature of the engine 10.

[0040] In the above embodiment, the case where a single ECU 100 controls the hybrid vehicle is illustrated, but it is not limited to this. 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.

[0041] As described above, the embodiments of the present invention have been described in detail, but 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.

Description of Reference Numerals

[0042] 10 Engine 14 K0 Clutch 15 Motor 18 Transmission 40 Throttle valve 100 ECU (Starting control unit, torque control unit, throttle control unit)

Claims

【Claim 1】 In a control device for a hybrid vehicle in which a clutch, a motor, and a transmission are provided in sequence on a power transmission path from an engine to wheels, When the motor is in operation, the clutch is in a released state, and there is a starting request for the engine, a starting control unit that starts the engine by cranking the engine with the motor by shifting the clutch to an engaged state while controlling the throttle opening of the engine to a starting opening; A torque control unit that controls the torques of the motor and the engine such that, after the engine is started and the clutch is in an engaged state, the sharing ratio of the motor with respect to the load of the transmission decreases while the sharing ratio of the engine with respect to the load increases; A throttle control unit that controls the throttle opening of the engine to the starting opening when the sharing ratio of the engine is equal to or less than a threshold value, and controls the throttle opening to an idle maintenance opening at which the engine speed maintains a target idle speed when the sharing ratio of the engine exceeds the threshold value, and The idle maintenance opening is larger than the starting opening, The starting opening is an opening set in consideration of the load of the engine when the sharing ratio of the engine is 0%, The threshold value is the sharing ratio of the engine corresponding to the amount of torque of the engine that can be increased by adjusting a parameter related to the torque of the engine other than the throttle opening of the engine in a state where the throttle opening of the engine is maintained at the starting opening, and is set to a value greater than 0% and less than 50%, The torque control unit controls the torque of the engine such that the sharing ratio of the engine increases by adjusting the parameter in a state where the throttle opening of the engine is maintained at the starting opening when the sharing ratio of the engine is equal to or less than the threshold value. A control device for a hybrid vehicle.

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