Drive force control system

Patent metadata

Field	Value
Publication number	US-2018237014-A1
Application number	US-201815901123-A
Country	US
Kind code	A1
Filing date	Feb 21, 2018
Priority date	Feb 21, 2017
Publication date	Aug 23, 2018
Grant date	—

Abstract

A drive force control system appropriately controls motors each connected to a corresponding one of drive wheels, so that a vehicle can be propelled with high efficiency. First motor and second motors are controlled in such a manner that a sum of torques transmitted to a right front wheel and a left rear wheel equals to a total value of required torques of the right front wheel and the left rear wheel. A target torque of the first motor and a target torque of the second motor achieving a smallest amount of power output from an electrical power source, for the output torques from the first motor and the second motor are calculated. A torque is generated by the first motor based on the target torque of the first motor calculated, and a torque is generated by the second motor based on the target torque of the second motor calculated.

First claim

What is claimed is:

1 . A drive force control system, comprising:
a first motor connected to a right drive wheel; a second motor connected to a left drive wheel; an electrical power source that supplies electric power to the first motor and the second motor; a clutch that allows a torque transmission between the first motor and the second motor, in which a torque transmitting capacity is variable; and a controller that controls output torques from the first motor and the second motor, wherein the controller is configured to control the output torques of the first motor and the second motor in such a manner as to equalize a sum of torques transmitted to the right drive wheel and the left drive wheel to propel the vehicle while setting the torque transmitting capacity of the clutch greater than a predetermined value, to a total value of required torques of the right drive wheel and the left drive wheel, calculate a target output torque of the first motor and a target output torque of the second motor to minimize an output power from the electrical power source, and generate a torque by the first motor based on the calculated target output torque of the first motor, and generate a torque by the second motor based on the calculated target torque of the second motor.

2 . The drive force control system as claimed in claim 1 , wherein the controller is further configured to:
calculate a first reference torque of a first controlled motor as any one of the first motor and the second motor in such a manner as to maximize an efficiency of the first controlled motor when the first controlled motor is rotated at a speed based on a wheel speed of a first drive wheel as one of the right drive wheel and the left drive wheel connected to the first controlled motor, calculate a second reference torque of a second controlled motor as the other one of the first motor and the second motor based on a difference between the first reference torque and the total value, calculate the target output torque of the first controlled motor based on the first reference torque, and calculate the target output torque of the second controlled motor based on the second reference torque.

3 . The drive force control system as claimed in claim 2 , wherein the controller is further configured to:
calculate a plurality of first provisional torques by changing the first reference torque by a predetermined toque, and calculate a plurality of second provisional torques of the second controlled motor in such a manner that the sum is equalized to the total value, calculate a power consumption amount of the electrical power source to generate the first provisional torque by the first controlled motor and to generate the second provisional torque by the second controlled motor, each time the first reference torque is changed by the predetermined toque, set a target output torque of the first controlled motor to the first provisional torque that has been calculated immediately previously, when the power consumption amount of the electrical power source currently calculated is greater than the power consumption amount of the electrical power source immediately previously calculated, and set a target output torque of the second controlled motor to the second provisional torque that has been calculated immediately previously, when the power consumption amount of the electrical power source currently calculated is greater than the power consumption amount of the electrical power source immediately previously calculated.

4 . The drive force control system as claimed in claim 2 , wherein the controller is further configured to:
calculate an efficient torque of the first motor achieving a maximum efficiency of the first motor when the first motor is rotated at a speed based on the wheel speed of the right drive wheel, calculate an efficient torque of the second motor achieving a maximum efficiency of the second motor when the second motor is rotated at the speed based on the wheel speed of the left drive wheel, and designate one of the first motor and the second motor in which the efficient torque is greater as the first controlled motor.

5 . The drive force control system as claimed in claim 2 , wherein the controller is further configured to:
calculate a first power consumption amount of the electrical power source to generate a torque by the first motor in such a manner as to maximize the efficiency of the first motor, and to generate a torque by the second motor in such a manner that the sum torque is equalized to the required torque, calculate a second power consumption amount of the electrical power source to generate a torque the second motor in such a manner as to maximize the efficiency of the second motor, and to generate a torque by the first motor in such a manner that the sum torque is equalized to the required torque, designate the first motor as the first controlled motor when the first power consumption amount is smaller than the second power consumption amount, and designate the second motor as the first controlled motor when the first power consumption amount is larger than the second power consumption amount.

6 . The drive force control system as claimed in claim 1 , wherein the controller is further configured to:
calculate a third reference torque as a maximum torque of a third controlled motor that is one of the first motor and the second motor, calculate a fourth reference torque of a fourth controlled motor that is the other one of the first motor and the second motor based on a difference between the third reference torque and the required torque, calculate a target torque of the third controlled motor based on the third reference torque, and calculate a target torque of the fourth controlled motor based on the fourth reference torque.

7 . The drive force control system as claimed in claim 6 , wherein the controller is further configured to:
calculate a plurality of third provisional torques by changing the third reference torque by a predetermined torque, and calculate a plurality of fourth provisional torques of the fourth controlled motor in such a manner that the sum is equalized to the total value, calculate the power consumption amount of the electrical power source to generate the third provisional torque by the third controlled motor and to generate the fourth provisional torque by s the fourth controlled motor, each time the third reference torque is changed by the predetermined torque, set a target torque of the third controlled motor to the third provisional torque immediately previously calculated, when the power consumption amount of the electrical power source currently calculated is greater than the power consumption amount of the electrical power source immediately previously calculated, and set a target torque of the fourth controlled motor to the fourth provisional torque immediately previously calculated, when the power consumption amount of the electrical power source currently calculated is greater than the power consumption amount of the electrical power source immediately previously calculated.

8 . The drive force control system as claimed in claim 6 , wherein the controller is further configured to:
control the torque transmitting capacity of the clutch, calculate the torque transmitting capacity of the clutch based on a difference between a torque transmitted to a second drive wheel as one of the left drive wheel and the right drive wheel connected to the third controlled motor and the required torque of the second drive wheel, when the third controlled motor generates the third reference torque, and calculate the fourth reference torque based on a torque transmitted to a third drive wheel as the other one

Assignees

• Toyota Motor Co Ltd

Inventors

• Nasu Takanobu
• Isono Hiroshi

Classifications

• F16D27/14

  Details · CPC title

• B62D11/04

  by means of separate power sources · CPC title

• B60W10/08

  including control of electric propulsion units, e.g. motors or generators · CPC title

• B60W10/02

  including control of driveline clutches · CPC title

• B60K7/0007

  the motor being electric · CPC title