JP-7856082-B2 - Control device for electric vehicles

Inventors

• 中神 壮馬
• 奥田 弘一
• 田端 淳

Assignees

• トヨタ自動車株式会社

Dates

Publication Date

20260511

Application Date

20231107

Claims (5)

1. A control device for an electric vehicle comprising: a first motor and a second motor that drive the left and right front wheels respectively; a third motor and a fourth motor that drive the left and right rear wheels respectively; and a first electric oil pump, a second electric oil pump, a third electric oil pump, and a fourth electric oil pump that supply oil for cooling and lubrication to the first motor, the second motor, the third motor, and the fourth motor, respectively, and independently controlling the driving force of the front, rear, left, and right wheels, Each of the motors and each of the electric oil pumps is controlled by a controller, and the controller is If the operating state of any of the aforementioned electric oil pumps meets a predetermined continuous operation limit condition, and the electric vehicle is traveling in a straight line, A control device for an electric vehicle, characterized by performing oil pump protection control that restricts the continuous operation of the electric oil pump when the continuous operation restriction conditions are met, and reduces the output of the motors of either the front wheel or the rear wheel to which the oil is supplied from the electric oil pump that restricts the continuous operation, while increasing the output of the motor of the other wheel.
2. A control device for an electric vehicle according to claim 1, The aforementioned controller, A control device for an electric vehicle, characterized in that it performs the oil pump protection control in a four-wheel drive state in which the driving force is generated in all four wheels, front, rear, left, and right.
3. A control device for an electric vehicle according to claim 2, The electric vehicle is further equipped with a notification device that causes the occupants to recognize predetermined information. The aforementioned controller, A control device for an electric vehicle, characterized in that the notification device makes the occupant aware that the oil pump protection control is being executed and that the four-wheel drive state is being restricted.
4. A control device for an electric vehicle according to any one of claims 1 to 3, The motor cooling system further comprises cooling each of the aforementioned motors with coolant. The aforementioned controller, A control device for an electric vehicle, characterized in that, when performing the oil pump protection control, it cools each of the motors that increase the output with the coolant.
5. A control device for an electric vehicle according to claim 4, The aforementioned controller, A control device for an electric vehicle, characterized by increasing the amount of coolant after initiating the execution of the oil pump protection control.

Description

This invention relates to a control device for an electric vehicle equipped with at least a motor as a driving force source, and more particularly to a control device for an electric vehicle in which the four wheels (front, rear, left, and right) are each driven by independent motors. Patent Document 1 describes a front-wheel drive vehicle (electric vehicle) equipped with a front motor for driving the front wheels and a rear motor for driving the rear wheels. In this electric vehicle described in Patent Document 1, the relationship between the thermal ratings of the front motor and the rear motor is set to a specific state (for example, the thermal rating of the front motor is higher than that of the rear motor). Furthermore, when the operation of the rear motor is limited (when the drive operation is limited, or when the regenerative operation is limited), the operation of the front motor (drive operation or regenerative operation) is increased. On the other hand, when the operation of the front motor is limited, the operation of the rear motor is reduced in order to achieve a target distribution ratio for the front and rear driving force. This maintains a balance of front and rear driving force, ensuring the driving stability of the electric vehicle. Furthermore, Patent Document 2 describes an electric oil pump control device comprising a mechanical oil pump driven by a drive source (engine or motor), an electric oil pump operated by electrical energy (motor power), and a pump control means for operating the electric oil pump while the mechanical oil pump is stopped. In the electric oil pump control device described in Patent Document 2, the electric oil pump is operated on the condition that its continuous operating time does not exceed a predetermined allowable operating time. If the continuous operating time of the electric oil pump exceeds the predetermined allowable operating time, the drive source is started and the mechanical oil pump is operated. In other words, to protect the electric oil pump, the source of hydraulic pressure is switched from the electric oil pump, which has a limited continuous operating time, to another oil pump that is not subject to this limitation. Japanese Patent Publication No. 2001-112114Patent No. 3867521 Figure 1 is a schematic diagram showing the configuration (drive system and control system) of the electric vehicle to be controlled in this invention.Figure 2 is a diagram showing an example of a specific configuration of an electric vehicle to be controlled by this invention, and is a gear train diagram showing the drive system (gear transmission mechanism) of the front wheel drive unit that drives the left and right front wheels of the electric vehicle, respectively.Figure 3 is a diagram showing an example of a specific configuration of an electric vehicle to be controlled by this invention, and is a gear train diagram showing the drive system (gear transmission mechanism) of the rear wheel drive unit that drives the left and right rear wheels of the electric vehicle, respectively.Figure 4 is a flowchart illustrating an example of the control performed by the control device for the electric vehicle of this invention.Figure 5 is a time chart showing an image of the continuous operation switching time (continuous operation limiting condition) when executing the control shown in the flowchart of Figure 4. Embodiments of this invention will be described with reference to the drawings. Note that the embodiments shown below are merely examples of how this invention can be implemented and do not limit the invention. The vehicle controlled in this embodiment of the invention is a four-wheel drive electric vehicle equipped with at least one motor as a driving force source, capable of driving all four wheels (front, rear, left, and right). The driving force source motor is capable of independently controlling the driving torque of at least the front wheels and the driving torque of the rear wheels. Therefore, it is equipped with at least two motors: one for driving the front wheels and one for driving the rear wheels. The following embodiment shows an example equipped with four motors (first motor 1, second motor 2, third motor 3, and fourth motor 4) capable of independently controlling the driving torque of each of the four wheels (front, rear, left, and right). The electric vehicle (hereinafter referred to as "vehicle") Ve shown in Figure 1 is equipped with a first motor (MG1) 1, a second motor (MG2) 2, a third motor (MG3) 3, and a fourth motor (MG4) 4 as its driving force source, i.e., motors for driving the vehicle. Vehicle Ve is also equipped with a first electric oil pump 5, a second electric oil pump 6, a third electric oil pump 7, and a fourth electric oil pump 8, respectively, which are provided on each of the motors 1, 2, 3, and 4. Furthermore, Vehicle Ve is equipped with a detection unit 9 and a controller (ECU) 10 for performing various control functions. Each of