Vehicle

Abstract

A vehicle is disclosed. A vehicle capable of appropriately calculating a power distribution ratio for each wheel even in a running state such as a state in which the rotational speeds of the wheels are different is provided. A vehicle including a plurality of wheels, a plurality of rotary electric machines that independently generate driving force or braking force for each wheel of the plurality of wheels, an electric power storage device that exchanges electric power with the plurality of rotary electric machines, a torque calculation unit that calculates a required torque for each of the plurality of wheels, and a rotational speed detection unit that detects a rotational speed for each of the plurality of wheels, includes a control device that performs control that calculates a distribution ratio of electric power from the electric power storage device to the plurality of rotary electric machines, that is, a power distribution ratio, in accordance with the required torque for each of the plurality of wheels and the rotational speed for each of the plurality of wheels.

Description

TECHNICAL FIELD

[0001] The present application relates to a vehicle. BACKGROUND

[0002] In Patent Literature 1, a technology is disclosed in which, in a vehicle in which a drive motor is mounted corresponding to each of front wheels and rear wheels, a control device calculates a distribution ratio of electric power from a battery to the drive motors of the front wheels and the rear wheels, that is, a power distribution ratio.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2015-053782 SUMMARY

[0006] In a case where each wheel is driven by a hub motor or the like, the rotational speeds of the left and right wheels in each of the front wheels and the rear wheels are not necessarily the same, but in the technology disclosed in Patent Literature 1, the rotational speeds of each wheel are not considered when the power distribution ratio is calculated.

[0007] The present application has been achieved in view of the above-described problems, and an object thereof is to provide a vehicle capable of appropriately calculating a power distribution ratio of each wheel even in a running state in which the rotational speeds of each wheel are different.

[0008] To solve the above-described problems and achieve the object, the present application provides a vehicle including: a plurality of wheels; a plurality of rotary electric machines that independently generate driving force or braking force for each wheel of the plurality of wheels; an electric power storage device that exchanges electric power with the plurality of rotary electric machines; a torque calculation unit that calculates a required torque of each of the plurality of wheels; and a rotational speed detection unit that detects a rotational speed of each of the plurality of wheels, characterized by including a control device that performs control to calculate a distribution ratio of electric power from the electric power storage device to the plurality of rotary electric machines, that is, a power distribution ratio, in accordance with the required torque of each of the plurality of wheels and the rotational speed of each of the plurality of wheels.

[0009] In the above-described aspect, the control device can calculate a torque command value of each of the plurality of wheels in accordance with electric power that can be supplied from the electric power storage device to each of the plurality of rotary electric machines, which is calculated using the power distribution ratio and an input-outputable electric power of the electric power storage device, and control the plurality of rotary electric machines.

[0010] Thus, each rotary electric machine can be appropriately controlled, and the maximum running function of the vehicle can be ensured.

[0011] In the above-described aspect, the plurality of wheels can be front wheels and rear wheels on the left and right.

[0012] Thus, in the 4-wheel drive vehicle in which a plurality of rotary electric machines are provided corresponding to the left and right front wheels and the left and right rear wheels, the power distribution ratio can be appropriately calculated even when the rotational speeds of the left and right front wheels and the left and right rear wheels are different.

[0013] The vehicle according to the present application has an effect that the power distribution ratio of each wheel can be appropriately calculated even in a driving state such as a difference in rotational speed of each wheel. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a diagram showing a schematic structure of a vehicle according to an embodiment.

[0015] Figure 2 is a diagram showing another schematic structure of a vehicle according to an embodiment.

[0016] Figure 3 is a diagram showing further another schematic structure of a vehicle according to an embodiment.

[0017] Figure 4 is a flowchart showing one example of control implemented by an MG-ECU according to an embodiment.

[0018] Figure 5 is a diagram showing a procedure of control until the MG-ECU calculates the power distribution ratio of each wheel and outputs a signal of the torque command of each wheel.

[0019] (EXPLANATION OF SYMBOLS)

[0020] 1, 1A, 1B: vehicle; 2, 2FR, 2FL, 2RR, 2RL, 2R, 2L: wheel; 3, 3FR, 3FL, 3RR, 3RL, 3R, 3L: in-wheel motor; 4: battery; 5: inverter; 6: MG-ECU; 7: main ECU; 8: motor; 9: differential device; 10FR, 10FL, 10RR, 10RL, 10R, 10L: wheel speed sensor. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of a vehicle according to the present application will be described. Furthermore, the present application is not limited by the present embodiment.

[0022] Figure 1 is a diagram showing a schematic structure of a vehicle 1 according to an embodiment. The vehicle 1 according to the embodiment is provided with in-wheel motors capable of individually controlling the torque imparted to a plurality of drive wheels, and in Figure 1 In the present embodiment, a structure example of a vehicle provided with in-wheel motors that individually impart torque to the front and rear wheels and the left and right wheels is shown.

[0023] The vehicle 1 according to the embodiment is provided with front wheels 2FR, 2FL on the left and right, rear wheels 2RR, 2RL on the left and right, wheel hub motors 3FR, 3FL as rotary motors provided to the front wheels on the left and right, wheel hub motors 3RR, 3RL provided to the rear wheels 2RR, 2RL on the left and right, a battery 4 as an electric power storage device, an inverter 5, an MG-ECU 6, a main ECU 7, and wheel speed sensors 10FR, 10FL, 10RR, 10RL, and the like.

[0024] The plurality of wheels 2FR, 2FL, 2RR, 2RL are suspended to a vehicle body of the vehicle 1 via respective independent suspension mechanisms. Further, in the following description, the wheels 2FR, 2FL, 2RR, 2RL are also simply denoted as wheels 2 without particular distinction. Inside the wheels of the wheels 2FR, 2FL, 2RR, 2RL, wheel hub motors 3FR, 3FL, 3RR, 3RL as a plurality of rotary motors are provided, respectively. Further, in the following description, the wheel hub motors 3FR, 3FL, 3RR, 3RL are also simply denoted as wheel hub motors 3FR without particular distinction. The wheel hub motors 3FR, 3FL, 3RR, 3RL are individually controlled to rotate by the MG-ECU 6, respectively, and independently, and drive forces or braking forces (regenerative braking forces) are independently generated with respect to the plurality of wheels 2FR, 2FL, 2RR, 2RL.

[0025] These wheel hub motors 3FR, 3FL, 3RR, 3RL are constituted by, for example, alternating current synchronous motors, and are connected to the battery 4 via the inverter 5. Therefore, at the time of driving of the wheel hub motors 3FR, 3FL, 3RR, 3RL, direct current electric power of the battery 4 is converted into alternating current electric power by the inverter 5, the alternating current electric power is supplied to the wheel hub motors 3FR, 3FL, 3RR, 3RL, and thus the wheel hub motors 3FR, 3FL, 3RR, 3RL are controlled to be motored, and driving torques are imparted to the wheels 2FR, 2FL, 2RR, 2RL.

[0026] In addition, the wheel hub motors 3FR, 3FL, 3RR, 3RL are also capable of being controlled to regenerate using the rotational energy of the wheels 2FR, 2FL, 2RR, 2RL. That is, at the time of regenerative power generation of the wheel hub motors 3FR, 3FL, 3RR, 3RL, the rotational energy of the wheels 2FR, 2FL, 2RR, 2RL is converted into electric energy by the wheel hub motors 3FR, 3FL, 3RR, 3RL, and the electric power generated at this time is accumulated to the battery 4 via the inverter 5. At this time, braking torques based on the regenerative power generation are imparted to the wheels 2FR, 2FL, 2RR, 2RL.

[0027] The inverter 5 is connected with the MG-ECU 6 that controls the rotation state of the wheel hub motors 3FR, 3FL, 3RR, 3RL. The MG-ECU 6 is an electronic circuit that is physically constituted of a known microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an interface, and the like. The MG-ECU 6 performs an operation using data input to the RAM, data stored to the ROM, and the like, and outputs the operation result as an instruction signal.

[0028] The MG-ECU 6 is constituted to input, for example, detection signals from various sensors such as wheel speed sensors 10FR, 10FL, 10RR, 10RL that detect the rotation speed of each wheel 2, rotation angle sensors that detect the rotation angle of the output shaft of the wheel hub motors 3FR, 3FL, 3RR, 3RL, and the like, information signals from the inverter 5, and the like. Among them, the output torque (motor torque) of the wheel hub motors 3FR, 3FL, 3RR, 3RL is respectively calculated by the MG-ECU 6 from the signals input from the inverter 5 to the MG-ECU 6. For example, in a case where it is detected that the wheel hub motors 3FR, 3FL, 3RR, 3RL are subjected to motoring control by the input signals from the inverter 5, the amount of power or the current value supplied to the wheel hub motors 3FR, 3FL, 3RR, 3RL at that time can be detected, and the motor torque of the wheel hub motors 3FR, 3FL, 3RR, 3RL is respectively calculated therefrom. In addition, the rotation speed of the wheel hub motors 3FR, 3FL, 3RR, 3RL can also be respectively calculated from the current value at the time of controlling the rotation of the wheel hub motors 3FR, 3FL, 3RR, 3RL.

[0029] On the other hand, the MG-ECU 6 is constituted to output signals that respectively control the rotation of the wheel hub motors 3FR, 3FL, 3RR, 3RL from the MG-ECU 6 via the inverter 5. That is, a control signal for controlling the current supplied to or recovered from the wheel hub motors 3FR, 3FL, 3RR, 3RL in order to control the rotation (motoring / regeneration) of the wheel hub motors 3FR, 3FL, 3RR, 3RL is output from the MG-ECU 6 to the inverter 5. In addition, the MG-ECU 6 is connected with the main ECU 7.

[0030] The main ECU 7 is a higher-level electronic control device that controls other ECUs. It comprises various electronic control devices, including the MG-ECU 6 and the electronic control device controlling the battery 4. Physically, the main ECU 7 is an electronic circuit primarily composed of a known microcomputer, including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and interfaces. The main ECU 7 performs calculations using data input to RAM and stored in ROM, and outputs the results as instruction signals.

[0031] The main ECU 7 is configured to receive detection signals directly or via other electronic control devices (ECUs), such as wheel speed sensors 10FR, 10FL, 10RR, 10RL that detect the rotational speed (wheel speed) of each wheel 2, rotation angle sensors that detect the rotational angle of the output shaft of the hub motors 3FR, 3FL, 3RR, 3RL, and other sensors, as well as information signals from the inverter 5.

[0032] In addition, each wheel 2 is provided with a braking mechanism. Each braking mechanism is a known braking device, such as a disc brake or a drum brake, and these various braking devices are appropriately selected and provided.

[0033] In addition, Figure 1 The diagram shows a structural example of a four-wheel drive vehicle 1 with hub motors 3FR, 3FL, 3RR, and 3RL installed on the left and right front wheels 2FR and 2FL and the left and right rear wheels 2RR and 2RL respectively. However, other examples include... Figure 2 The vehicle 1A shown is a four-wheel drive vehicle with hub motors 3FR and 3FL installed on the left and right front wheels 2FR and 2FL respectively, and a drive unit consisting of a motor 8 for driving the left and right rear wheels 2RR and 2RL, and a differential device 9. Furthermore, it can also be as shown... Figure 3 The vehicle 1B shown is a two-wheel drive vehicle with hub motors 3R and 3L respectively installed on the left and right wheels 2R and 2L, and wheel speed sensors 10R and 10L detecting the rotational speed of the left and right wheels 2R and 2L. In summary, the vehicle to be addressed in this invention can be a structure in which multiple drive wheels, such as the hub motors 3 described above, can independently and directly drive the left and right drive wheels.

[0034] In the vehicle 1 according to the embodiment, the MG-ECU 6 calculates and determines the required torque of each wheel 2 (the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL), for example, in accordance with the required driving force of the vehicle 1 corresponding to the accelerator opening degree and the vehicle speed and the like. That is, the MG-ECU 6 functions as a torque calculation unit that calculates the required torque of each wheel 2. Further, the MG-ECU 6 determines the required power of each wheel 2 (FR required power, FL required power, RR required power, RL required power) from the battery 4 to each in-wheel motor 3 (in-wheel motors 3FR, 3FL, 3RR, 3RL) provided to each wheel 2 in accordance with the required torque of each wheel 2 and the rotational speed of each wheel 2, and calculates the power distribution ratio of the power from the battery 4 to each in-wheel motor 3 of each wheel 2. Thus, in the vehicle 1 according to the embodiment, the power distribution ratio of each wheel 2 can be appropriately calculated by the MG-ECU 6 even in a driving state such as a state in which the rotational speeds of each wheel 2 are different. In addition, the control of calculating such a power distribution ratio of each wheel 2 can be implemented by the main ECU 7 instead of the MG-ECU 6, or by the MG-ECU 6 and the main ECU 7 in cooperation.

[0035] Figure 4 is a flowchart showing one example of the control implemented by the MG-ECU 6 according to the embodiment. Figure 5 is a diagram explaining the process of the control until the MG-ECU 6 calculates the power distribution ratio of each wheel 2 and outputs the torque command of each wheel 2.

[0036] As shown in Figure 4 , first, the MG-ECU 6 calculates the required driving force of the vehicle 1 in accordance with the accelerator opening degree and the vehicle speed and the like (step S1). Next, the MG-ECU 6 determines the required torque of each wheel 2 of the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL in accordance with the required driving force of the vehicle 1 (step S2). Next, the MG-ECU 6 multiplies the required torque of each wheel 2 by the rotational speed of each wheel 2 to determine the required power of each wheel 2 (FR required power, FL required power, RR required power, RL required power) from the battery 4 to each in-wheel motor 3 (in-wheel motors 3FR, 3FL, 3RR, 3RL) provided to each wheel 2 as shown in Figure 5 . Next, the MG-ECU 6 divides the required power of each wheel 2 by the total required power to determine the power distribution ratio of the power from the battery 4 to each in-wheel motor 3 of each wheel 2 as shown in Figure 5 . Next, the MG-ECU 6 multiplies the required torque of each wheel 2 by the rotational speed of each wheel 2 to determine the required power of each wheel 2 (FR required power, FL required power, RR required power, RL required power) from the battery 4 to each in-wheel motor 3 (in-wheel motors 3FR, 3FL, 3RR, 3RL) provided to each wheel 2 as shown in Figure 5The illustrated multiplying the power distribution ratio of each wheel 2 and the input / output electric power amount (Win•Wout) of the battery 4 (inverter 5) determines the upper and lower limits of the electric power that can be supplied from the battery 4 to each hub motor 3 of each wheel 2, that is, the upper and lower limit powers of each wheel 2 (FR upper and lower limit power, FL upper and lower limit power, RR upper and lower limit power, RL upper and lower limit power). Next, the MG-ECU 6 calculates the torque command value of each wheel 2 based on the upper and lower limit powers of each wheel 2 corrected according to the implementation of the upper and lower limit processing, and outputs a signal for controlling the torque command of each hub motor 3 to the inverter 5 (step S5). Figure 5 The illustrated multiplying the power distribution ratio of each wheel 2 and the input / output electric power amount (Win•Wout) of the battery 4 (inverter 5) determines the upper and lower limits of the electric power that can be supplied from the battery 4 to each hub motor 3 of each wheel 2, that is, the upper and lower limit powers of each wheel 2 (FR upper and lower limit power, FL upper and lower limit power, RR upper and lower limit power, RL upper and lower limit power). Next, the MG-ECU 6 calculates the torque command value of each wheel 2 based on the upper and lower limit powers of each wheel 2 corrected according to the implementation of the upper and lower limit processing, and outputs a signal for controlling the torque command of each hub motor 3 to the inverter 5 (step S5).

[0037] Thus, the MG-ECU 6 can appropriately control each hub motor 3 even in a state where the input / output electric power of the battery 4 is limited due to thermal constraints or power constraints, and in a running state such as a state where the rotational speeds of each wheel 2 provided with each hub motor 3 are different, and can ensure the maximum running function of the vehicle 1.

Claims

1. A vehicle comprising: a plurality of wheels; a plurality of rotary electric machines that independently generate driving force or braking force for each of the plurality of wheels; an electric storage device that exchanges electric power with the plurality of rotary electric machines; a torque calculation unit that calculates a required torque for each of the plurality of wheels based on a required driving force of the vehicle; and a rotational speed detection unit that detects a rotational speed of each of the plurality of wheels, characterized in that the vehicle comprises a control device that performs control in which a required electric power for each of the plurality of rotary electric machines is determined based on the required torque for each of the plurality of wheels calculated by the torque calculation unit and the rotational speed of each of the plurality of wheels detected by the rotational speed detection unit, and a distribution ratio of electric power from the electric storage device to the plurality of rotary electric machines, i.e., a power distribution ratio, is calculated by dividing the required electric power for each of the plurality of rotary electric machines by a total required electric power of the required electric power for each of the plurality of rotary electric machines.

2. The vehicle according to claim 1, characterized in that the control device calculates a torque command value for each of the plurality of wheels based on electric power that can be supplied from the electric storage device to each of the plurality of rotary electric machines calculated using the power distribution ratio and an input-outputable electric power of the electric storage device, and controls the plurality of rotary electric machines.

3. The vehicle according to claim 1 or 2, characterized in that the plurality of wheels are front wheels and rear wheels on the left and right sides. ​ ​ ​ ​ ​ ​ ​ ​ ​

Images