Vehicle control device

Abstract

To provide a controller of a vehicle which prevents a poor charge state of a battery at a highland.SOLUTION: A controller of a vehicle which includes: an engine which is a traveling power source; an electric generator which generates electricity through driving force at the time of an idle operating state of the engine; and a battery into which electricity generated by the electric generator is charged. The controller comprises: a determination part which determines whether a charging request to the battery is present while the vehicle is at a highland; and an engine control part which increases, when an affirmative determination is done by the determination part, a target idle rotation number of the engine relative to a case when a negative determination is done by the determination part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] At high altitudes, the air density is low, which can reduce the engine's driving force and thus the vehicle's driving force. For this reason, hybrid vehicles are known that ensure vehicle driving force by increasing the motor's driving force at high altitudes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-182570 Summary of the Invention [Problem to be solved by the invention]

[0004] At high altitudes, the driving force of the engine may decrease, which may reduce the amount of power generated by the generator that uses the driving force of the engine, resulting in a risk of the battery becoming insufficiently charged.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle control device that prevents the battery from becoming insufficiently charged at high altitudes. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a vehicle that includes an engine as a driving power source, a generator that can generate electricity using the driving force of the engine when it is idling, and a battery that charges the electricity generated by the generator, the control device for a vehicle that includes: a determination unit that determines whether there is a request to charge the battery when the vehicle is at high altitude; and an engine control unit that, if a positive determination is made by the determination unit, increases the target idle speed of the engine more than if a negative determination is made by the determination unit.

[0007] When the determination unit makes a positive determination, the engine control unit may increase the target idle speed as the outside air pressure decreases.

[0008] The generator may be a motor that is a power source for traveling.

[0009] The vehicle may include a clutch provided between the motor and the engine, and the motor may generate electricity using the driving force of the engine in an idling state with the clutch engaged. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a vehicle control device that prevents the battery from becoming insufficiently charged at high altitudes. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] FIG. 2 is a flowchart showing an example of control executed by the ECU. [Figure 3] FIG. 3 is an example of a map that defines the relationship between the outside air pressure and the increase in the target idle speed. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Hybrid vehicle configuration] FIG. 1 is a schematic diagram of a hybrid vehicle 1. In the hybrid vehicle 1, a K0 clutch 14, a motor 15, a wet clutch 18, and a transmission 19 are provided in this order in a power transmission path from an engine 10 to drive wheels 13. The engine 10 and the motor 15 are installed as a driving power source for the hybrid vehicle 1. The engine 10 is, for example, a V6 gasoline engine, but the number of cylinders is not limited thereto, and the engine 10 may be an in-line gasoline engine or a diesel engine. The K0 clutch 14, the motor 15, the wet clutch 18, and the transmission 19 are provided in a transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a differential 12.

[0013] The K0 clutch 14 is provided between the engine 10 and the motor 15 on the power transmission path. The K0 clutch 14 receives a supply of hydraulic pressure from a disengaged state and enters an engaged state, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 enters a disengaged state when the hydraulic pressure supply is stopped, and interrupts the power transmission between the engine 10 and the motor 15. The engaged state is a state in which both engagement elements of the K0 clutch 14 are connected and the engine 10 and the motor 15 are rotating at the same speed. The disengaged state is a state in which both engagement elements of the K0 clutch 14 are disengaged.

[0014] The motor 15 is connected to the battery 16 via an inverter 17. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied from the battery 16, and also functions as a generator that generates electric power to charge the battery 16 in response to power transmitted from the engine 10 and 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 (Electronic Control Unit) 100, which will be 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 power running in which the motor 15 outputs torque, the inverter 17 converts the DC voltage from the battery 16 into an AC voltage and adjusts the power supplied to the motor 15. In the case of regenerative running in which the motor 15 generates power, the inverter 17 converts the AC voltage from the motor 15 into a DC voltage and adjusts the power supplied to the battery 16.

[0016] The transmission 19 is a stepped automatic transmission that changes the gear ratio in multiple stages by changing the gear position, but is not limited to this and may be a continuously variable automatic transmission. The transmission 19 is provided between the motor 15 and the drive wheels 13 on the power transmission path. A wet clutch 18 is provided that receives a supply of hydraulic pressure and enters an engaged state 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 wet clutch 18, and the transmission 19 via the hydraulic control mechanism 22. The hydraulic control mechanism 22 is provided with hydraulic circuits for the K0 clutch 14, the wet clutch 18, and the transmission 19, as well as various hydraulic control valves for controlling the operating hydraulic pressures thereof. Note that a torque converter equipped with a lock-up clutch may be provided instead of the wet clutch 18.

[0018] The hybrid vehicle 1 is provided with an ECU 100 as a control device for the vehicle. The ECU 100 is an electronic control unit that includes a processing circuit that performs various arithmetic processes related to vehicle driving control and a memory that stores control programs and data. The ECU 100 functionally realizes a determination unit and an engine control unit, which will be described in detail later.

[0019] The ECU 100 controls the operation of the engine 10 and the motor 15. Specifically, the ECU 100 controls the torque and rotation speed of the engine 10 by controlling the throttle opening, ignition timing, and fuel injection amount of the engine 10. The ECU 100 controls the rotation speed and torque of the motor 15 by controlling the inverter 17 to adjust the amount of power exchanged between the motor 15 and the battery 16. The ECU 100 also controls the operation of the K0 clutch 14, the wet clutch 18, and the transmission 19 through control of the hydraulic control mechanism 22.

[0020] The ECU 100 receives signals from an ignition switch 71, a crank angle sensor 72, a motor rotation speed sensor 73, an external air pressure sensor 74, and an SOC sensor 75. The crank angle sensor 72 detects the rotation speed of the crankshaft of the engine 10, i.e., the engine rotation speed. The motor rotation speed sensor 73 detects the rotation speed of the output shaft of the motor 15. The external air pressure sensor 74 detects the external air pressure. The SOC sensor 75 detects the SOC (State Of Charge), which indicates the charge amount of the battery 16. The ECU 100 may estimate the charge amount of the battery 16 using a known method without using the SOC sensor.

[0021] The ECU 100 drives the hybrid vehicle in either an electric driving mode (hereinafter referred to as BEV (Battery Electric Vehicle) mode) or a hybrid driving mode (hereinafter referred to as HEV (Hybrid Electric Vehicle) mode). In the BEV mode, the ECU 100 disengages the K0 clutch 14 and drives the vehicle using power from the motor 15. In the HEV mode, the ECU 100 switches the K0 clutch 14 to an engaged state and drives the vehicle using power from at least the engine 10. The HEV mode includes a mode in which the vehicle drives using power from the engine 10 alone, and a mode in which the motor 15 is powered and the vehicle drives using both the engine 10 and the motor 15 as power sources.

[0022] The driving mode is switched based on the vehicle's required driving force, which is calculated from the vehicle speed and accelerator pedal position, and the SOC of the battery 16. For example, if the required driving force is relatively small and the SOC is relatively high, the BEV mode is selected. If the required driving force is relatively large or the SOC of the battery 16 is relatively low, the HEV mode is selected.

[0023] [Control performed by ECU] 2 is a flowchart showing an example of control executed by ECU 100. This control is repeatedly executed at predetermined intervals while the ignition is on. ECU 100 determines whether or not hybrid vehicle 1 is at high altitude (step S1). Specifically, when the outside air pressure detected by outside air pressure sensor 74 is equal to or lower than a predetermined value lower than standard atmospheric pressure, it is determined that hybrid vehicle 1 is at high altitude. Note that this determination is not limited to being made based on the outside air pressure, and may be made based on, for example, map information including the current location and altitude data identified by a GPS (Global Positioning System) device. If the result in step S1 is No, this control ends.

[0024] If the answer is Yes in step S1, the ECU 100 determines whether there is a request to charge the battery 16 (step S2). A request to charge the battery 16 is issued when the charge amount of the battery 16 detected by the SOC sensor 75 falls below a predetermined value. If the answer is No in step S2, this control ends. Steps S1 and S2 are an example of processing executed by the determination unit.

[0025] If the answer is Yes in step S2, the ECU 100 increases the target idle speed of the engine 10 by a predetermined value (step S3). This ensures the driving force of the engine 10 in an idle operating state when the hybrid vehicle 1 is at high altitude. As a result, a decrease in the power generated by the regenerative operation of the motor 15 when the engine 10 is in an idle operating state is suppressed, and insufficient charging of the battery 16 at high altitude is prevented. Step S3 is an example of processing executed by the engine control unit.

[0026] The increase in the target idle speed may be a variable value rather than a fixed value. For example, the lower the outside air pressure, the higher the target idle speed. FIG. 3 is an example of a map that defines the relationship between the outside air pressure and the increase in the target idle speed. This map is defined in advance based on experimental results and simulation results. The map of FIG. 3 defines the increase in the target idle speed to be larger as the outside air pressure decreases. This makes it possible to prevent the battery 16 from being insufficiently charged at high altitudes while suppressing deterioration in fuel efficiency of the engine 10.

[0027] In the above embodiment, the hybrid vehicle 1 is provided with the engine 10 and the motor 15 as a power source for running, but the present invention is not limited to this. For example, the hybrid vehicle may be provided with only an engine as a power source for running. In this case, an alternator linked to the rotation of the engine can be used as a generator.

[0028] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0029] 1 Hybrid vehicle 10 Engine 15 Motor (generator) 100 ECU (vehicle control unit, judgment unit, engine control unit)

Claims

[Claim 1] A control device for a vehicle including an engine as a driving power source, a generator capable of generating electricity using driving force of the engine in an idling state, and a battery for charging the generated electricity of the generator, a determination unit that determines whether or not there is a request to charge the battery while the vehicle is at high altitude; an engine control unit that, when a positive determination is made by the determination unit, increases a target idle speed of the engine more than when a negative determination is made by the determination unit so as to prevent insufficient charging of the battery at high altitudes; Equipped with When the determination unit makes a positive determination, the engine control unit increases the target idle rotation speed as the outside air pressure decreases, The generator is a motor that is a driving power source, the vehicle includes a clutch provided between the motor and the engine, With the clutch engaged, the motor generates electricity using the driving force of the engine in an idling operation state, When the determination unit determines that there is no request to charge the battery while the vehicle is at high altitude, the engine control unit does not increase the target idle rotation speed.

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