Hybrid vehicle control device

Abstract

To provide a hybrid vehicle control device which prevents a battery from excessive charging while suppressing an excessive engine rotation speed when an engine is started.SOLUTION: A control device is for a hybrid vehicle which includes an engine and a motor serving as power sources and a battery capable of supplying electricity to the motor and can charge the battery with regenerative power. The control device comprises: a charging power estimation section which estimates charging power for charging the battery when the hybrid vehicle decelerates; and an engine start-up processing section which starts the engine when the charging power is less than the electric power capable of charging the battery. The charging power estimation section estimates the charging power by adding up first regenerative power which is regenerative power generated by the motor when the hybrid vehicle decelerates and second regenerative power which is the regenerative power generated by the motor when the motor suppresses an engine rotation speed if the engine rotation speed exceeds a target rotation speed when the engine is started up.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A conventional technique for starting the engine according to the battery's charge capacity has been known for a control device for a hybrid vehicle equipped with an engine, a motor, and a battery that supplies power to the motor (Patent Document 1). In the control device described in Patent Document 1, when the battery's charge capacity is low, the motor is used to start the engine, consuming power and preventing the battery from being overcharged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-192813 Summary of the Invention [Problem to be solved by the invention]

[0004] When starting the engine, the engine speed may exceed the target speed, and in such cases it is necessary to suppress the engine speed using the motor. However, suppressing the engine speed using the motor may result in the battery being charged by the motor's regeneration, which may result in overcharging. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a control device for a hybrid vehicle having an engine and a motor as power sources, and a battery capable of supplying power to the motor, the battery being capable of being charged with regenerative power. The control device includes a charge power estimation unit that estimates charge power to the battery when the hybrid vehicle is decelerating, and an engine start processing unit that starts the engine when the charge power is less than the power that can be input to the battery. The charge power estimation unit estimates the charge power by summing first regenerative power, which is power generated by regeneration of the motor when the hybrid vehicle is decelerating, and second regenerative power, which is regenerative power of the motor generated by the motor suppressing the rotational speed of the engine when the rotational speed of the engine exceeds a target rotational speed when the engine is started. According to this type of control device, the charging power is estimated by adding up the first regenerative power and the second regenerative power, and the engine is started if the charging power is less than the inputtable power, thereby preventing the engine rotation speed from exceeding the limit when the engine is started and preventing overcharging of the battery. (2) In the above embodiment, the charging power estimation unit may estimate the second regenerative power using at least one of the vehicle speed of the hybrid vehicle, the gear ratio of the transmission of the hybrid vehicle, and the target rotational speed, and may estimate the charging power using the estimated second regenerative power. According to this type of control device, the second regenerative power is estimated using at least one of the vehicle speed of the hybrid vehicle, the gear ratio of the transmission of the hybrid vehicle, and the target rotational speed, and the estimated second regenerative power is used to estimate the charging power, so that the charging power can be estimated more accurately and overcharging of the battery can be more stably suppressed. (3) In the above embodiment, the charging power estimation unit may estimate the charging power by using the second regenerative power that is set in advance. According to the control device of this aspect, the charging power is estimated using the second regenerative power that is set in advance, so that the processing in the control device can be prevented from becoming complicated. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an explanatory diagram showing a schematic configuration of a drive system including a control device according to an embodiment of the present invention; [Figure 2] 1 is a block diagram showing a schematic configuration of a control device according to an embodiment of the present invention; [Figure 3] 4 is a flowchart showing the procedure of a start determination process according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. Implementation: A-1. System Configuration: 1 is an explanatory diagram showing a schematic configuration of a drive system 100 including a control device 40 of this embodiment. The drive system 100 is mounted on a vehicle 200 configured as a hybrid vehicle and transmits power for driving the vehicle 200. The drive system 100 includes a front unit 10, a rear unit 20, a battery 30, a control device 40, a pair of front wheels 50f, and a pair of rear wheels 50r. The drive system 100 includes an engine and a motor, as described below, and the vehicle 200 has an EV driving mode in which the vehicle runs using the motor as a driving power source with the engine stopped, and an HV driving mode in which the vehicle runs using the engine and motor as a driving power source.

[0009] The front unit 10 includes an engine 11 , a first clutch 12 , a first motor 13 , a second clutch 14 , a transmission 15 , a first inverter 16 , and an electric oil pump 17 .

[0010] The engine 11 is a first power source of the vehicle 200. The engine 11 receives fuel from a fuel supply system (not shown) and operates as an internal combustion engine to generate driving torque for propelling the vehicle 200. The driving torque output from the engine 11 is transmitted to a pair of front wheels 50f via a first clutch 12, a first motor 13, a second clutch 14, and a transmission 15.

[0011] The first motor 13 is a second power source of the vehicle 200. The first motor 13 receives power from the first inverter 16 and rotates to generate drive torque for propelling the vehicle 200. The drive torque output from the first motor 13 is transmitted to the pair of front wheels 50f via the second clutch 14 and the transmission 15. The first motor 13 can also generate regenerative power for charging the battery 30 by regenerating energy when the vehicle 200 decelerates. The first motor 13 can also start the engine 11 and control the rotational speed of the engine 11.

[0012] The first clutch 12 is provided in a drive transmission path between the engine 11 and the first motor 13. The first clutch 12 can switch between an engaged state and a disengaged state, thereby switching the drive transmission path between a disconnected state and an engaged state. The first clutch 12 is, for example, a dry multi-plate hydraulic friction engagement device, and is configured with a plurality of friction plates stacked on top of each other. The operation of the first clutch 12 is controlled by an electric oil pump 17. The electric oil pump 17 is rotated using power supplied from the battery 30, thereby applying hydraulic pressure to the first clutch 12 and operating the first clutch 12.

[0013] The second clutch 14 is a so-called "starting clutch" and is provided in the drive transmission path between the first motor 13 and the transmission 15. The second clutch 14 can switch between an engaged state and a disengaged state, thereby switching the drive transmission path between a disconnected state and an engaged state. The second clutch 14 is, for example, a wet-type multi-plate hydraulic friction engagement device and is configured with a plurality of friction plates stacked on top of each other. The operation of the second clutch 14 is controlled by the electric oil pump 17, similar to the first clutch 12. Note that the first clutch 12 and the second clutch 14 may be controlled by different hydraulic control systems.

[0014] The first inverter 16 uses the power supplied from the battery 30 in response to a control signal from the control device 40 to supply power (three-phase AC current) to the first motor 13, thereby driving the first motor 13. This allows the first inverter 16 to rotate the output shaft of the first motor 13 in a rotation direction and at a rotation speed according to the control signal from the control device 40.

[0015] The rear unit 20 includes a second motor 21 and a second inverter 22 .

[0016] The second motor 21 is a third power source of the vehicle 200. The second motor 21 receives power from the second inverter 22 and rotates to generate drive torque for propelling the vehicle 200. The drive torque output from the second motor 21 is transmitted to the pair of rear wheels 50r. The second motor 21 also regenerates energy when the vehicle 200 decelerates, thereby generating regenerative power for charging the battery 30.

[0017] The second inverter 22 uses power supplied from the battery 30 in response to a control signal from the control device 40 to supply power (three-phase AC current) to the second motor 21, thereby driving the second motor 21. This allows the second inverter 22 to rotate the output shaft of the second motor 21 in a direction and at a rotation speed that correspond to the control signal from the control device 40. Note that the drive system 100 does not necessarily have to include the rear unit 20, and in such a configuration, the rear wheels 50r may be configured to rotate in a driven manner relative to the front wheels 50f driven by the front unit 10.

[0018] The battery 30 can supply power to the first motor 13 and the second motor 21 via the first inverter 16 and the second inverter 22. The battery 30 can also be charged with regenerative power supplied from the first motor 13 and the second motor 21 via the first inverter 16 and the second inverter 22. The battery 30 may be, for example, a lithium ion secondary battery, a nickel-metal hydride secondary battery, or the like.

[0019] The control device 40 acquires information from various sensors mounted on the vehicle 200. In this embodiment, the control device 40 acquires an accelerator opening from an accelerator pedal sensor 61, a brake pedal force from a brake pedal sensor 62, and a shift position of a shift lever from a shift position sensor 63. The control device 40 also acquires the vehicle speed of the vehicle 200 from a vehicle speed sensor 64. The control device 40 also acquires the rotational speed of the first motor 13 from a first rotational speed sensor 65 installed in the first motor 13, and the rotational speed of the second motor 21 from a second rotational speed sensor 67 installed in the second motor 21. The control device 40 also acquires the SOC (State Of Charge) of the battery 30 from a battery sensor 66 installed in the battery 30.

[0020] The control device 40 controls each component of the drive system 100 using information acquired from various sensors. More specifically, the control device 40 performs engine torque control of the engine 11, drive control of the first motor 13 via control of the first inverter 16, drive control of the second motor 21 via control of the second inverter 22, and control of the switching operation of the first clutch 12 and the second clutch 14 via control of the electric oil pump 17, so as to realize acceleration or deceleration corresponding to the acquired accelerator opening and brake pedal force. The control device 40 also performs gear shift control of the transmission 15 so as to achieve a gear ratio corresponding to the acquired shift position. The control device 40 also performs charge / discharge control of the battery 30 according to the acquired SOC of the battery 30. The control device 40 is not limited to the above controls, and may be configured to perform various other controls related to drive control of the vehicle 200.

[0021] When the SOC of the battery 30 becomes equal to or higher than a predetermined threshold during deceleration of the vehicle 200, the control device 40 executes control to start the engine 11 to consume power and generate deceleration through engine friction in order to avoid overcharging the battery 30. Furthermore, when an overshoot occurs during start-up of the engine 11, in which the rotational speed of the engine 11 exceeds a target rotational speed, the control device 40 executes control to suppress the overshoot using the first motor 13 (hereinafter also referred to as “overshoot suppression control”). The “target rotational speed” of the engine 11 refers to a rotational speed that is set to mitigate shock that may occur when starting the engine 11 and transitioning from the EV driving mode to the HV driving mode. The target rotational speed is determined, for example, according to the current rotational speed of the first motor 13, so that the magnitude of the difference between the rotational speed of the first motor 13 and the rotational speed of the engine 11 is less than a predetermined threshold. In the overshoot suppression control, the rotational speed of the engine 11 is suppressed by the drive resistance between the engine 11 and the front wheels 50f and the suppression torque by the first motor 13. The first motor 13 generates electricity by regenerating the energy generated during this suppression. The process for realizing the start of the engine 11 and the overshoot suppression control as described above will be referred to as "engine start process" in the following description.

[0022] Fig. 2 is a block diagram showing a schematic configuration of the control device 40 of this embodiment. As shown in Fig. 2, the control device 40 is configured as an ECU (Electronic Control Unit) having a CPU 41 and a memory 42. The CPU 41 executes a control program pre-stored in the memory 42 to function as a charge power estimation unit 411 and an engine start processing unit 412. Note that the control device 40 also includes functional units that execute control of each unit of the drive system 100 described above. However, Fig. 2 shows only the functional units involved in executing the engine start processing described above, and does not show other functional units. Furthermore, each functional unit may be realized by a plurality of different ECUs.

[0023] The charging power estimation unit 411 estimates charging power to the battery 30. "Charging power" refers to power charged to the battery 30 in accordance with drive control when the vehicle 200 is decelerated. In this embodiment, the charging power estimation unit 411 estimates charging power to the battery 30 by summing regenerative power generated by regeneration of the first motor 13 and the second motor 21 when the vehicle 200 is decelerated (hereinafter also referred to as "deceleration power") and regenerative power generated by the first motor 13 suppressing the rotation speed of the engine 11 (hereinafter also referred to as "suppression power"). The deceleration power corresponds to "first regenerative power" in this disclosure. The suppression power corresponds to "second regenerative power" in this disclosure. Methods for calculating the deceleration power and the suppression power will be described later.

[0024] When the charging power estimated by the charging power estimation unit 411 is less than the available input power of the battery 30, the engine start processing unit 412 controls each unit of the drive system 100 and starts the above-mentioned engine start processing. "Available input power" means the power that can be input to the battery 30 from the current SOC until the battery 30 is fully charged. This is because if the engine start processing is started when the available input power is low, the charging power may exceed the available input power, resulting in overcharging.

[0025] A-2. Start determination process: 3 is a flowchart showing the procedure of the start determination process of this embodiment. In this embodiment, the control device 40 starts the start determination process when the SOC of the battery 30 becomes equal to or higher than a predetermined threshold in the EV driving mode.

[0026] In step S10, the charging power estimation unit 411 calculates the deceleration power. In this embodiment, the charging power estimation unit 411 calculates the deceleration power in the current traveling state of the vehicle 200 by using the rotation speed of the first motor 13 acquired from the first rotation speed sensor 65, the rotation speed of the second motor 21 acquired from the second rotation speed sensor 67, and the deceleration of the vehicle 200 required by the brake pedal force acquired from the brake pedal sensor 62.

[0027] In step S20, the charging power estimation unit 411 estimates the suppression-period power. In this embodiment, the suppression-period power is estimated using at least one of the vehicle speed of the vehicle 200 acquired from the vehicle speed sensor 64, the gear ratio of the transmission 15, and the target rotation speed of the engine 11.

[0028] More specifically, when the vehicle speed of the vehicle 200 is high, the rotational speed of the first motor 13 is high, and the difference between the engine rotational speed and the motor rotational speed during an overshoot is smaller than when the vehicle speed of the vehicle 200 is low, so the amount of suppression of the engine rotational speed by the first motor 13 is smaller and the power during suppression is smaller. Also, when the gear ratio of the transmission 15 is large, the driving resistance is greater and the engine rotational speed is more likely to be suppressed than when the gear ratio is small, so the amount of suppression of the engine rotational speed by the first motor 13 is smaller and the power during suppression is smaller. Also, when the target rotational speed is high, the difference between the engine rotational speed and the target rotational speed during an overshoot is smaller than when the target rotational speed is small, so the amount of suppression of the engine rotational speed by the first motor 13 is smaller and the power during suppression is smaller.

[0029] In step S30, engine start processing unit 412 determines whether or not the charging power, which is the sum of the deceleration power and the suppression power, is less than the inputtable power.

[0030] If the charging power is not less than the available input power (step S30: No), in other words, if the charging power is equal to or greater than the available input power, the charging power estimation unit 411 executes step S10 again. On the other hand, if the charging power is less than the available input power (step S30: Yes), in step S40, the engine start processing unit 412 starts the engine start processing. With this, the control device 40 ends the start determination processing.

[0031] According to the control device 40 of the embodiment described above, the charging power is estimated by adding up the deceleration power and the suppression power, and the engine 11 is started if the charging power is less than the inputtable power, so that the engine rotation speed can be prevented from exceeding the limit when the engine is started, while also preventing overcharging of the battery 30.

[0032] Furthermore, the suppression power is estimated using at least one of the vehicle speed of the vehicle 200, the gear ratio of the transmission 15, and the target rotation speed, and the estimated suppression power is used to estimate the charging power, so that the charging power can be estimated more accurately and overcharging of the battery 30 can be more stably suppressed.

[0033] B. Other Embodiments: (B1) In the above embodiment, the charging power estimation unit 411 estimates the suppression-time power and estimates the charging power using at least one of the vehicle speed of the vehicle 200, the gear ratio of the transmission 15, and the target rotation speed of the engine 11, but the present disclosure is not limited to this. The charging power estimation unit 411 may estimate the charging power using deceleration power that is identified and set in advance by conducting experiments or the like. According to this embodiment, there is no need to estimate the suppression-time power in the start determination process, and therefore the start determination process can be prevented from becoming complicated.

[0034] (B2) In the above embodiment, the control device 40 calculates the deceleration power by acquiring the rotational speeds of the first motor 13 and the second motor 21 from the first rotational speed sensor 65 and the second rotational speed sensor 67, respectively, but the present disclosure is not limited to this. The control device 40 may calculate the deceleration power by using the rotational speeds of the first motor 13 and the second motor 21 that the control device 40 itself has instructed the first inverter 16 and the second inverter 22 to use, rather than the values ​​detected by the first rotational speed sensor 65 and the second rotational speed sensor 67. According to this embodiment, there is no need to mount the first rotational speed sensor 65 and the second rotational speed sensor 67 on the vehicle 200, which can suppress an increase in the manufacturing cost of the vehicle 200.

[0035] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0036] 10...front unit, 11...engine, 12...first clutch, 13...first motor, 14...second clutch, 15...transmission, 16...first inverter, 17...electric oil pump, 20...rear unit, 21...second motor, 22...second inverter, 30...battery, 40...control device, 41...CPU, 42...memory, 50f...front wheels, 50r...rear wheels, 61...accelerator pedal sensor, 62...brake pedal sensor, 63...shift position sensor, 64...vehicle speed sensor, 65...first rotational speed sensor, 66...battery sensor, 67...second rotational speed sensor, 100...drive system, 200...vehicle, 411...charging power estimation unit, 412...engine start processing unit

Claims

1. A control device for a hybrid vehicle having an engine and a motor as power sources, and a battery capable of supplying power to the motor, and capable of charging the battery with regenerative power, a charging power estimation unit that estimates charging power to the battery when the hybrid vehicle is decelerating; an engine start processing unit that starts the engine when the charging power is less than the power that can be input to the battery; Equipped with the charging power estimation unit estimates the charging power by summing a first regenerative power, which is power generated by regeneration of the motor when the hybrid vehicle is decelerating, and a second regenerative power, which is power generated by the motor suppressing the rotation speed of the engine when the rotation speed of the engine exceeds a target rotation speed when the engine is started. Control device.

2. The control device according to claim 1, the charging power estimation unit estimates the second regenerative power using at least one of a vehicle speed of the hybrid vehicle, a gear ratio of a transmission of the hybrid vehicle, and the target rotation speed, and estimates the charging power using the estimated second regenerative power. Control device.

3. The control device according to claim 1, the charging power estimation unit estimates the charging power by utilizing the second regenerative power that is set in advance; Control device.

Images