Hybrid vehicle control device

Abstract

To provide a control device of a hybrid vehicle that enables a series-type hybrid vehicle to achieve improvement in starting performance by an operation of pressing down an accelerator pedal and a brake pedal, and a hybrid vehicle.SOLUTION: A control device of a hybrid vehicle is equipped with an internal combustion engine, an electric motor for power generation that can convert power of the internal combustion engine to electric power, an electric motor for driving that supplies driving power for travelling to a driving wheel, and a battery that outputs electric power to either of the electric motor for power generation or the electric motor for driving, and the control device makes the electric motor for power generation perform power running by electric power outputted from the battery, so as to start the internal combustion engine, when an operation of pressing down both of an accelerator pedal and a brake pedal is performed in a state where the hybrid vehicle is in a travelling range and is in a stopped state including travelling at an extreme low speed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] For example, a series hybrid system includes an engine, a generator motor that generates electricity using engine power, a drive motor that generates driving force for traveling, and a battery that stores the power supplied to the drive motor. A lithium-ion battery is used as the battery.

[0003] In a hybrid vehicle equipped with such a hybrid system, when the output required of the drive motor is smaller than the output of the battery, the drive motor is driven by electric power from the battery, and drive force is transmitted from the drive motor to the drive wheels. On the other hand, when the output required of the drive motor exceeds the output of the battery, engine power is converted into electric power by a generator motor, and the converted electric power is used to drive the drive motor, and drive force is transmitted from the drive motor to the drive wheels. Furthermore, when the hybrid vehicle decelerates, the drive motor operates in regenerative mode, converting the power transmitted from the drive wheels to the drive motor into electric power. At this time, the drive motor acts as resistance to the driving system, and this resistance acts as braking force (regenerative braking force) that brakes the hybrid vehicle. Furthermore, the electric power generated by the drive motor is stored in the battery and used to drive the drive motor. This improves the fuel efficiency of the hybrid vehicle.

[0004] Among such hybrid vehicles, in vehicles equipped with a torque converter, a technology has been disclosed in which torque is amplified by the torque converter when both the brake and accelerator are depressed while the vehicle is stopped in order to make a sudden start (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-186585 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in series hybrid vehicles that do not have a direct transmission structure for engine torque, even if both the brake and accelerator pedals are depressed while the vehicle is stopped, there is a problem that sufficient power cannot be supplied to the drive motor because power for starting the engine must be reserved, especially when the battery capacity is small, resulting in poor starting performance. In other words, if the engine is started after the vehicle speed has increased to a certain level by depressing the accelerator pedal (i.e., power is used by the generator motor), the power available to the drive motor is limited, making it impossible to improve starting performance.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a control device for a hybrid vehicle that can improve starting performance by depressing both the accelerator and brake in a series-type hybrid vehicle. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the control device for a hybrid vehicle of the present invention is a control device for a hybrid vehicle that includes an internal combustion engine, a generator motor that can convert the power of the internal combustion engine into electric power, a drive motor that supplies driving force to the drive wheels for traveling, and a battery that outputs electric power to at least one of the generator motor or the drive motor, and is characterized in that when both the accelerator pedal and the brake pedal are depressed in the traveling range and in a stopped state including at very low speeds, the generator motor is powered to start the internal combustion engine using the electric power output from the battery.

[0009] In addition, the control device for a hybrid vehicle according to the present invention is characterized in that when the brake pedal is released from a state in which both are depressed, the generator motor is switched to regenerative operation to convert the power of the internal combustion engine into electricity, and the electricity generated by the generator motor and the electricity output from the battery are supplied to the drive motor.

[0010] In addition, the control device for a hybrid vehicle according to the present invention, when the rotation speed of the internal combustion engine is increasing and the charge level of the battery is equal to or greater than a predetermined level, uses the power output from the battery to power the generator motor, thereby maintaining the internal combustion engine at a rotation speed equal to or greater than the predetermined level.

[0011] In addition, the control device for a hybrid vehicle according to the present invention switches the generator motor to regenerative operation when the charge level of the battery is less than a predetermined level while the rotation speed of the internal combustion engine is increasing, converts the power of the internal combustion engine into electricity, and supplies the electricity to the battery to charge it. [Effects of the Invention]

[0012] According to the present invention, in a series hybrid vehicle, it is possible to improve starting performance by depressing both the accelerator and the brake. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing an example of a configuration of a main part of a hybrid vehicle according to an embodiment. [Figure 2] FIG. 2 is a time chart showing an example of the flow of control operations in response to accelerator operation in the hybrid vehicle according to the embodiment. [Figure 3] FIG. 3 is a flowchart showing an example of the flow of control operations in response to accelerator operation in the hybrid vehicle according to this embodiment. [Figure 4]FIG. 4 is a time chart showing an example of the flow of control operations in response to depression of both the accelerator and the brake in the hybrid vehicle according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of the flow of control operations in response to depression of both the accelerator and the brake in the hybrid vehicle according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of a control device for a hybrid vehicle according to the present invention will be described in detail with reference to Figures 1 to 5. Furthermore, the present invention is not limited to the following embodiments, and the components in the following embodiments include those that would be easily conceived by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, various omissions, substitutions, modifications, and combinations of the components can be made without departing from the spirit of the following embodiments.

[0015] (Hybrid vehicle configuration) 1 is a diagram showing an example of a main configuration of a hybrid vehicle according to an embodiment, and the main configuration of a hybrid vehicle 1 according to this embodiment will be described with reference to FIG.

[0016] The hybrid vehicle 1 is a vehicle equipped with a series hybrid system 2. The hybrid vehicle 1 also includes drive wheels 17, an ECU (Electronic Control Unit) 31, an accelerator sensor 32, a brake switch 33, and a vehicle speed sensor 34.

[0017] The hybrid system 2 includes an engine 11, a generator motor (MG1) 12 (electric motor for generating electricity), a drive motor (MG2) 13 (electric motor for driving electricity), a battery 14, and a PCU (Power Control Unit) 15.

[0018] The engine 11 is, for example, an internal combustion engine such as a gasoline engine.

[0019] The generator motor 12 is, for example, a permanent magnet synchronous motor for converting the power of the engine 11 into electric power. The rotating shaft of the generator motor 12 is mechanically connected to the crankshaft of the engine 11 via a gear (not shown). For example, an engine output gear is supported on the crankshaft of the engine 11 so as not to rotate relative thereto, and a motor gear is supported on the rotating shaft of the generator motor 12 so as not to rotate relative thereto, and the engine output gear and the motor gear are meshed.

[0020] The drive motor 13 is, for example, a permanent magnet synchronous motor that is larger than the generator motor 12. A rotary shaft of the drive motor 13 is connected to a drive system 16 for driving and rotating drive wheels 17. The drive system 16 includes a differential gear, and the power of the drive motor 13 is transmitted to the differential gear, and then distributed and transmitted from the differential gear to drive wheels 17 consisting of left and right front wheels or rear wheels. This causes the left and right drive wheels 17 to rotate, and the hybrid vehicle 1 moves forward or backward.

[0021] The battery 14 is a battery pack made up of a combination of multiple secondary batteries (for example, lithium ion batteries). The battery 14 outputs DC power of, for example, about 200 to 350 [V].

[0022] The PCU 15 is a unit for controlling the driving of the generator motor 12 and the drive motor 13. The PCU 15 includes a first inverter 21, a second inverter 22, and a converter .

[0023] The first inverter 21 is an inverter device that converts DC power from the converter 23 into AC power, or converts AC power generated by the generator motor 12 into DC power. The second inverter 22 is an inverter device that converts DC power from the converter 23 into AC power, or converts AC power generated by regenerative operation of the drive motor 13 into DC power. The converter 23 is a device that boosts the DC power output from the battery 14, or reduces the DC power output from the first inverter 21 or the second inverter 22.

[0024] When starting the engine 11, the DC power output from the battery 14 is boosted by the converter 23, the boosted DC power is converted to AC power by the first inverter 21, and the converted AC power is supplied to the generator motor 12. This causes the generator motor 12 to perform power running, and the engine 11 is motored (cranked) by the generator motor 12. When the rotation speed of the crankshaft of the engine 11 has increased to the rotation speed required for starting due to motoring, the ignition plug of the engine 11 is sparked, and the engine 11 starts.

[0025] When the hybrid vehicle 1 is traveling, the drive motor 13 is operated in a power running mode, and the drive motor 13 generates power.

[0026] When the hybrid vehicle 1 is running, if the output required of the drive motor 13 is smaller than the output of the battery 14, the hybrid vehicle 1 runs in EV (Electric Vehicle) mode. That is, in EV running, the engine 11 is stopped, no power is generated by the generator motor 12, and the drive motor 13 is driven by power supplied from the battery 14 via the converter 23 and the second inverter 22.

[0027] On the other hand, when the output required of the drive motor 13 exceeds the output of the battery 14 while the hybrid vehicle 1 is running, the hybrid vehicle 1 runs as an HV (Hybrid Vehicle). That is, during HV running, the engine 11 is in operation and the generator motor 12 is operated to generate electricity (regeneratively), so that the power of the engine 11 is converted into AC power by the generator motor 12. The AC power from the generator motor 12 is then converted into DC power by the first inverter 21, and the DC power is converted into AC power by the second inverter 22. The AC power is supplied to the drive motor 13, thereby driving the drive motor 13.

[0028] When the hybrid vehicle 1 decelerates, the drive motor 13 undergoes regenerative operation, and power transmitted from the drive wheels 17 to the drive motor 13 is converted into AC power. At this time, the drive motor 13 acts as a resistor in the drivetrain 16, and this resistance acts as a braking force (regenerative braking force) that brakes the hybrid vehicle 1. At this time, in the PCU 15, the AC power supplied from the drive motor 13 to the second inverter 22 is converted into DC power by the second inverter 22, and the DC power is stepped down by the converter 23. The stepped-down DC power is then supplied to the battery 14, thereby charging the battery 14.

[0029] The ECU 31 is a control device that controls the hybrid system 2. The ECU 31 is connected to an accelerator sensor 32, a brake switch 33, and a vehicle speed sensor 34. The ECU 31 obtains an accelerator opening, which is the ratio of the current operation amount of the accelerator pedal to the maximum operation amount, from the detection signal output from the accelerator sensor 32. The ECU 31 also obtains the frequency of the detection signal (pulse signal) output from the detection signal from the vehicle speed sensor 34, and converts the frequency into vehicle speed.

[0030] The accelerator sensor 32 is a sensor that outputs a detection signal corresponding to the amount of operation of the accelerator pedal (accelerator opening) operated by the driver's foot.

[0031] The brake switch 33 is a sensor that outputs a brake signal that indicates the amount of operation of the brake pedal operated by the driver or whether or not the brake pedal has been depressed.

[0032] The vehicle speed sensor 34 is a sensor that outputs, as a detection signal, a pulse signal synchronized with the rotation of a rotating body that rotates as the hybrid vehicle 1 travels.

[0033] The hybrid vehicle 1 is equipped with a plurality of ECUs including an ECU 31. Each ECU has a microcontroller unit (microcomputer), which includes, for example, a central processing unit (CPU), a nonvolatile memory such as a flash memory, and a volatile memory such as a dynamic random access memory (DRAM). The plurality of ECUs are connected to enable bidirectional communication using a controller area network (CAN) communication protocol. Each ECU is connected to various sensors required for control, and receives detection signals from the connected sensors. In addition to the detection signals received from the various sensors, each ECU also receives information required for control from other ECUs.

[0034] (Regarding normal operation when the accelerator pedal is operated) Fig. 2 is a time chart showing an example of the flow of control operations in response to accelerator operation in a hybrid vehicle according to the embodiment. Fig. 3 is a flowchart showing an example of the flow of control operations in response to accelerator operation in a hybrid vehicle according to the embodiment. With reference to Figs. 2 and 3, the control operations when the accelerator pedal is operated in hybrid vehicle 1 according to the embodiment will be described.

[0035] First, with reference to FIG. 2, an outline of the flow of control operations when the accelerator pedal is operated in the hybrid vehicle 1 will be described.

[0036] As shown in Fig. 2, when the driver first operates the accelerator pedal, the DC power output from the battery 14 begins to increase, the DC power is boosted by the converter 23 and converted to AC power by the second inverter 22, and the AC power drives the drive motor (MG2) 13 to rotate, causing the torque to begin to increase. As the torque of the drive motor 13 increases, the rotation speed of the drive motor 13 increases, the rotation speed of the drive wheels 17 increases, and the vehicle speed of the hybrid vehicle 1 increases. In other words, at this stage, the output of the battery 14 contributes to the powering operation of the drive motor 13, the engine 11 does not start, and the hybrid vehicle 1 runs in EV mode ("(1) MG2 = Battery" shown in Fig. 2).

[0037] Next, when the DC power output from the battery 14 exceeds a predetermined threshold value Th, the portion of the DC power exceeding the threshold value Th is converted to AC power by the first inverter 21, and the AC power powers the generator motor (MG1) 12 to power running, thereby starting the engine 11. Then, the rotational drive torque of the generator motor 12 increases the rotation speed of the engine 11. That is, at this stage, the output of the battery 14 contributes to the power running of the generator motor 12 and the power running of the drive motor 13 ("(2) MG2 = battery - MG1" shown in FIG. 2). In other words, the power running of the drive motor 13 is contributed by the output of the battery 14 minus the power used for power running of the generator motor 12 as the engine 11 starts and the rotation speed increases, so that the power available to the drive motor 13 is limited.

[0038] Then, when the rotation speed of the engine 11 reaches or exceeds a predetermined rotation speed, the generator motor 12 switches to regenerative operation, and the power of the engine 11 is converted to AC power by the generator motor 12. The AC power from the generator motor 12 is then converted to DC power by the first inverter 21, and the DC power is converted to AC power by the second inverter 22, and the AC power is supplied to the drive motor 13. That is, at this stage, the output of the battery 14 and the power generated by the regenerative operation of the generator motor 12 contribute to the power running operation of the drive motor 13, and the hybrid vehicle 1 accelerates by HV running ("(3) MG2 = battery + MG1" shown in FIG. 2).

[0039] Next, with reference to FIG. 3, the flow of control operations when the accelerator pedal is operated in the hybrid vehicle 1 will be described in detail.

[0040] <Step S11> First, the ECU 31 calculates a target torque from the accelerator opening detected by the accelerator sensor 32 and the rotation speed of the drive motor (MG2) 13. Then, the process proceeds to step S12.

[0041] <Step S12> The ECU 31 determines whether the target output, which is the product of the calculated target torque and the rotation speed, is equal to or greater than a predetermined value. If the target output is equal to or greater than the predetermined value (step S12: Yes), the ECU 31 proceeds to step S13. If the target output is less than the predetermined value (step S12: No), the ECU 31 proceeds to step S17.

[0042] <Step S13> The ECU 31 powers the generator motor (MG1) 12 using part of the DC power output from the battery 14, and starts the engine 11. If the engine 11 has already started, this step is skipped. Then, the process proceeds to step S14.

[0043] <Step S14> If the rotation speed of the engine 11 is increasing (step S14: Yes), the process proceeds to step S15, and if the rotation speed of the engine 11 has reached a predetermined rotation speed (step S14: No), the process proceeds to step S16.

[0044] <Step S15> When the rotation speed of the engine 11 is increasing, the ECU 31 converts the DC power output from the battery 14 and boosted by the converter 23 into AC power using the first inverter 21 and the second inverter 22, respectively, to power the generator motor 12 and the drive motor 13. In other words, the power consumption of the drive motor 13 is contributed to by the output of the battery 14 minus the power used for powering the generator motor 12 as the engine 11 starts and the rotation speed increases. Then, the process returns to step S11.

[0045] <Step S16> When the rotation speed of the engine 11 reaches a predetermined rotation speed, the ECU 31 switches the generator motor 12 to regenerative operation and causes the generator motor 12 to convert the power of the engine 11 into AC power. The ECU 31 then converts the AC power from the generator motor 12 into DC power using the first inverter 21, converts the DC power into AC power using the second inverter 22, and supplies the AC power to the drive motor 13. As a result, the output of the battery 14 and the power generated by the regenerative operation of the generator motor 12 contribute to the power running operation of the drive motor 13, and the hybrid vehicle 1 accelerates by HV running. Then, the process returns to step S11.

[0046] <Step S17> The ECU 31 converts the DC power output from the battery 14 and boosted by the converter 23 into AC power using the second inverter 22, and powers the drive motor (MG2) 13. As the torque of the drive motor 13 increases, the rotation speed of the drive motor 13 increases, the rotation speed of the drive wheels 17 increases, and the vehicle speed of the hybrid vehicle 1 increases. This causes the hybrid vehicle 1 to run in EV mode. Then, the process returns to step S11.

[0047] As described above, in the control operation when the accelerator pedal is operated in the hybrid vehicle 1, after the vehicle speed of the hybrid vehicle 1 increases to a certain extent after the accelerator pedal is depressed, the power output of the battery 14 minus the power used in the power running of the generator motor 12 as the engine 11 starts and the rotation speed increases is contributed to the power running of the drive motor 13, resulting in a state in which the power available to the drive motor 13 is limited. Therefore, even if both the accelerator pedal and the brake pedal are depressed, if control is performed using the operation procedure shown in FIG. 2, the driver's desire to improve starting performance cannot be realized. Therefore, in order to realize this desire, the control operation for improving starting performance when both the accelerator pedal and the brake pedal are depressed in the hybrid vehicle 1 according to this embodiment will be described in detail below.

[0048] (Regarding control operations when both the accelerator pedal and brake pedal are operated) Fig. 4 is a time chart showing an example of the flow of control operations when both the accelerator pedal and the brake pedal are depressed in a hybrid vehicle according to this embodiment. Fig. 5 is a flowchart showing an example of the flow of control operations when both the accelerator pedal and the brake pedal are depressed in a hybrid vehicle according to this embodiment. With reference to Figs. 4 and 5, the control operations when both the accelerator pedal and the brake pedal are depressed in a hybrid vehicle 1 according to this embodiment will be described.

[0049] First, with reference to FIG. 4, an outline of the flow of control operations when both the accelerator pedal and the brake pedal are depressed in the hybrid vehicle 1 will be described.

[0050] As shown in Fig. 4, when the driver first depresses both the accelerator pedal and the brake pedal, the DC power from the battery 14 is boosted by the converter 23 and converted to AC power by the first inverter 21. The AC power then drives the generator motor (MG1) 12 to rotate, and the torque begins to increase. Then, the torque from the rotational drive of the generator motor 12 starts the engine 11, and the rotation speed increases. That is, at this stage, the drive motor (MG2) 13 does not perform power running, the hybrid vehicle 1 remains stopped, and the output of the battery 14 contributes only to the power running of the generator motor 12 ("(4) MG1 = Battery" shown in Fig. 4).

[0051] Next, when the rotation speed of the engine 11 reaches a predetermined rotation speed and the brake pedal is released, the generator motor 12 switches to regenerative operation, and the power of the engine 11 is converted to AC power by the generator motor 12. The AC power from the generator motor 12 is then converted to DC power by the first inverter 21, and the DC power is converted to AC power by the second inverter 22, and the AC power is supplied to the drive motor 13. In other words, the output of the battery 14 and the power generated by the regenerative operation of the generator motor 12 contribute to the power running operation of the drive motor 13, and the hybrid vehicle 1 starts running in HV running mode ("(5) MG2 = battery + MG1" shown in FIG. 4). In this case, the rate of change in the torque increase of the drive motor 13 shown in FIG. 4 is greater than the rate of change in the torque increase of the drive motor 13 in normal operation, indicated by the dotted line (see FIG. 2), thereby improving the starting performance of the hybrid vehicle 1.

[0052] Next, with reference to FIG. 5, a detailed description will be given of the flow of control operations when both the accelerator pedal and the brake pedal are depressed in the hybrid vehicle 1.

[0053] <Step S31> ECU 31 determines whether the driver has depressed both the accelerator pedal and the brake pedal when the selector lever is in the drive range and the vehicle is stopped, including at very low speeds. If the driver has depressed both the accelerator pedal and the brake pedal when the selector lever is in the drive range and the vehicle is stopped, including at very low speeds (step S31: Yes), the process proceeds to step S32. On the other hand, if the driver has depressed only the accelerator pedal when the selector lever is in the drive range and the vehicle is stopped, including at very low speeds (including when the brake pedal is released from both the accelerator pedal and the brake pedal being depressed) (step S31: No), the process proceeds to step S38.

[0054] <Step S32> The ECU 31 converts the DC power output from the battery 14 and boosted by the converter 23 into AC power using the first inverter 21, and powers the generator motor (MG1) 12 using the AC power to start the engine 11. Note that if the engine 11 has already started, this step is skipped, and the process then proceeds to step S33.

[0055] <Step S33> If the rotation speed of the engine 11 is increasing (step S33: Yes), the process proceeds to step S34, and if the rotation speed of the engine 11 has reached a predetermined rotation speed (step S33: No), the process proceeds to step S35.

[0056] <Step S34> While the rotation speed of the engine 11 is increasing, the ECU 31 converts the DC power output from the battery 14 and boosted by the converter 23 into AC power using the first inverter 21, and powers the generator motor (MG1) 12 using the AC power. Then, the process returns to step S31.

[0057] <Step S35> The ECU 31 determines whether the SOC (State Of Charge) of the battery 14 has decreased. Specifically, the ECU 31 determines whether the amount of charge of the battery 14 is less than a predetermined amount. For example, the ECU 31 may recognize the SOC of the battery 14 via the PCU 15 or CAN communication. If the amount of charge of the battery 14 is less than the predetermined amount (step S35: Yes), the process proceeds to step S36, and if the amount of charge is equal to or greater than the predetermined amount (step S35: No), the process proceeds to step S37.

[0058] <Step S36> When the charge amount of the battery 14 falls below a predetermined amount, the ECU 31 switches the generator motor 12 to regenerative operation and causes the generator motor 12 to convert the power of the engine 11 into AC power. That is, the ECU 31 switches the state of the engine 11 from motoring to firing. Then, the ECU 31 converts the AC power into DC power using the first inverter 21, reduces the voltage of the DC power using the converter 23, and supplies it to the battery 14 to charge it. Then, the process returns to step S31.

[0059] <Step S37> If the charge amount of the battery 14 is equal to or greater than the predetermined amount, the ECU 31 converts the DC power output from the battery 14 and boosted by the converter 23 into AC power using the first inverter 21, and powers the generator motor (MG1) 12 using the AC power. That is, the ECU 31 puts the engine 11 into a motoring state and maintains the rotation speed of the engine 11 at or greater than a predetermined rotation speed. Then, the process returns to step S31.

[0060] <Steps S38 to S44> The processing of steps S38 to S44 is the same as the processing of steps S11 to S17 shown in Fig. 3. At this time, if the rotation speed of the engine 11 reaches a predetermined rotation speed in step S31 and the brake pedal is released, steps S38 to S41 and S43 are processed in this order, the generator motor 12 switches to regenerative operation, the output of the battery 14 and the power generated by the generator motor 12 contribute to the power running operation of the drive motor 13, and the hybrid vehicle 1 starts running in HV running with good start-up performance. However, in this case, the engine 11 has already started, so the processing of step S40 is skipped.

[0061] As described above, the ECU 31 of the hybrid vehicle 1 according to this embodiment includes the engine 11, the generator motor 12 that can convert the power of the engine 11 into electric power, the drive motor 13 that supplies drive force to the drive wheels 17 for traveling, and the battery 14 that outputs electric power to at least one of the generator motor 12 and the drive motor 13. When both the accelerator pedal and the brake pedal are depressed in the traveling range and the vehicle is stopped, including at very low speeds, the ECU 31 powers the generator motor 12 with electric power output from the battery 14 to start the engine 11. This allows the generator motor 12 to increase the rotation speed of the engine 11 in advance, so that more electric power for starting the engine 11 can be supplied to the drive motor 13 when starting. Therefore, in a series-type hybrid vehicle, the start-up performance can be improved by depressing both the accelerator and the brake, thereby improving drivability for the driver.

[0062] Furthermore, when the accelerator pedal and brake pedal are both depressed and the brake pedal is released, the ECU 31 switches the generator motor 12 to regenerative operation to convert the power of the engine 11 into electric power, and supplies the electric power generated by the generator motor 12 and the electric power output from the battery 14 to the drive motor 13. In this way, the engine 11 is started when both the accelerator pedal and the brake pedal are depressed, and when the brake pedal is released, all of the output from the battery 14 and the electric power generated by the generator motor 12 can be instantly supplied to the drive motor 13, thereby improving the starting performance of the hybrid vehicle 1.

[0063] Furthermore, when the rotation speed of the engine 11 is increasing and the charge level of the battery 14 is equal to or greater than a predetermined level, the ECU 31 powers the generator motor 12 using the power output from the battery 14 to maintain the engine 11 at or above the predetermined rotation speed. As a result, when the charge level of the battery 14 is sufficient, the generator motor 12 keeps the engine 11 rotating, thereby reducing unnecessary fuel consumption and maintaining a state in which power can be generated immediately.

[0064] Furthermore, when the rotation speed of the engine 11 is increasing and the charge level of the battery 14 is less than a predetermined level, the ECU 31 switches the generator motor 12 to regenerative operation, converts the power of the engine 11 into electricity, and supplies this electricity to charge the battery 14. As a result, when the battery 14 does not have enough charge to spare, firing the engine 11 starts power generation by the generator motor 12, allowing the charge level to be quickly restored and the generated power output to be immediately supplied to the drive motor 13. [Explanation of symbols]

[0065] 1 Hybrid vehicle 2 Hybrid system 11 Engine 12 Generator motor 13 Drive motor 14 Batteries 15 PCU 16 Drivetrain 17 Drive wheels 21 First inverter 22 Second inverter 23 Converter 31 ECU 32 Accelerator sensor 33 Brake switch 34 Vehicle speed sensor

Claims

1. A control device for a hybrid vehicle including an internal combustion engine, a generator motor capable of converting power of the internal combustion engine into electric power, a drive motor that supplies drive power to drive wheels, and a battery that outputs electric power to at least one of the generator motor or the drive motor, When both the accelerator pedal and the brake pedal are depressed in a driving range and in a stopped state including at very low speeds, the generator motor is powered by the electric power output from the battery to start the internal combustion engine; When the brake pedal is released from a state in which both pedals are depressed, the control device for a hybrid vehicle switches the generator motor to regenerative operation to convert the power of the internal combustion engine into electricity, and supplies the electricity generated by the generator motor and the electricity output from the battery to the drive motor.

2. A control device for a hybrid vehicle equipped with an internal combustion engine, a generator motor capable of converting the power of the internal combustion engine into electric power, a drive motor that supplies driving force to drive wheels, and a battery that outputs electric power to at least one of the generator motor or the drive motor, When both the accelerator pedal and the brake pedal are depressed in a driving range and in a stopped state including at very low speeds, the generator motor is powered by the electric power output from the battery to start the internal combustion engine; A control device for a hybrid vehicle that, when the rotation speed of the internal combustion engine is increasing and the charge level of the battery is equal to or greater than a predetermined level, uses the power output from the battery to power the generator motor, thereby maintaining the internal combustion engine at a rotation speed equal to or greater than the predetermined level.

3. 3. A control device for a hybrid vehicle according to claim 1, wherein, when the rotational speed of the internal combustion engine is increasing and the charge level of the battery is less than a predetermined level, the generator motor is switched to regenerative operation, the power of the internal combustion engine is converted into electric power, and the electric power is supplied to the battery to charge it.

Images