Search

CN-121989673-A - Rotor lock prevention system for electric vehicle and related method

CN121989673ACN 121989673 ACN121989673 ACN 121989673ACN-121989673-A

Abstract

The present disclosure provides a rotor lock prevention system for an electric vehicle and a related method. Rotor lock prevention systems and related methods are disclosed. An example apparatus includes an electric motor having an output shaft, a drive shaft for driving one or more wheels of a vehicle, a torque converter for operatively coupling the output shaft of the electric motor and the drive shaft, and a clutch movable between an open position and a closed position. The clutch fluidly couples the output shaft of the electric motor and the drive shaft when the clutch is in the open position. When the clutch is in the closed position, the clutch enables the electric motor to bypass the torque converter to mechanically couple the output shaft and the drive shaft of the electric motor.

Inventors

  • N. Qiu Qi
  • J. Haier
  • WESTON KERRY
  • M. D. Penny
  • B. F. diamond

Assignees

  • 福特全球技术公司

Dates

Publication Date
20260508
Application Date
20251031
Priority Date
20241106

Claims (15)

  1. 1. An apparatus, comprising: an electric motor (202) having an output shaft (214); -a drive shaft (216) for driving one or more wheels (220) of the vehicle; A torque converter for operatively coupling the output shaft (214) and the drive shaft (216) of the electric motor (202), and -A clutch (212) movable between an engaged position (304) and a disengaged position (302), the clutch (212) fluidly coupling the output shaft (214) and the drive shaft (216) of the electric motor (202) when the clutch (212) is in the disengaged position (302), -the clutch (212) enabling the electric motor (202) to bypass the torque converter to mechanically couple the output shaft (214) and the drive shaft (216) of the electric motor (202) when the clutch (212) is in the engaged position (304).
  2. 2. The apparatus of claim 1, wherein the clutch (212) effects slippage between the output shaft (214) of the electric motor (202) and the drive shaft (216) when the clutch (212) is in the disengaged position (302), the clutch (212) preventing slippage between the output shaft (214) of the electric motor (202) and the drive shaft (216) when the clutch (212) is in the engaged position (304).
  3. 3. The apparatus of any of claims 1-2, wherein the clutch (212) enables the output shaft (214) of the electric motor (202) to rotate at a first speed that is different from a second speed of the drive shaft (216) when the clutch (212) is in the disengaged position (302), the clutch (212) enabling the output shaft (214) of the electric motor (202) and the drive shaft (216) to rotate at the same speed when the clutch (212) is in the engaged position (304).
  4. 4. The apparatus of any of claims 1-3, further comprising a gearbox (218) coupled between the output shaft (214) of the electric motor (202) and the torque converter.
  5. 5. The apparatus of any of claims 1-4, further comprising a gearbox (218) coupled between the torque converter and the drive shaft (216).
  6. 6. The apparatus of any of claims 1-5, wherein the torque converter is a hydraulic torque converter.
  7. 7. The apparatus of any of claims 1-6, wherein the torque converter includes a turbine (226) and a pump impeller (222), wherein the pump impeller (222) is coupled to the output shaft (214) of the electric motor (202) and the turbine (226) is coupled to the drive shaft (216).
  8. 8. The apparatus of claim 7, wherein the clutch (212) is slidably coupled to the turbine (226).
  9. 9. The apparatus of claim 8, further comprising a valve (250, 252) fluidly coupled to the clutch (212), the valve (250, 252) movable between a first position and a second position; In the first position, the valve (250, 252) moves the clutch (212) to the engaged position (304) to mechanically couple the output shaft (214) of the motor and the drive shaft (216), and In the second position, the valve (250, 252) moves the clutch (212) to the disengaged position (302) to fluidly couple the output shaft (214) of the motor and the drive shaft (216).
  10. 10. The apparatus of claim 9, further comprising a controller for moving the valve (250, 252) to the second position in response to detecting a rotor lock condition of the vehicle and determining that a vehicle speed does not exceed a vehicle speed threshold.
  11. 11. The apparatus of claim 9, further comprising a controller for moving the valve (250, 252) to the second position and operating the electric motor (202) at least a minimum motor speed threshold in response to detecting a rotor lock condition.
  12. 12. The apparatus of claim 10, wherein the rotor lock condition of the vehicle comprises at least one of a tow mode, an off-road mode, an electric motor (202) stalling, an elevated grade, or an inverter condition.
  13. 13. The apparatus of any one of claims 1-12, further comprising: Interface circuitry (920); machine-readable instructions (932), and Programmable circuitry (912) to at least one of instantiate or execute the machine readable instructions (932) to: Activating a rotor lock prevention mode based on the detected vehicle condition; comparing the vehicle speed to a vehicle speed threshold; responsive to the vehicle speed not exceeding the vehicle speed threshold: Moving the clutch (212) of the torque converter to the disengaged position, and Maintaining a motor speed of the electric motor (202) greater than a motor speed threshold.
  14. 14. The apparatus of claim 13 wherein if the detected vehicle condition is an off-road condition, the programmable circuitry (912) activates the rotor lock prevention mode, or alternatively, Wherein the programmable circuitry (912) is operable to at least one of instantiate or execute the machine readable instructions (932) to adjust friction brakes of a wheel (220) in response to determining that the detected vehicle condition is in an off-road mode, or alternatively, Wherein the programmable circuitry (912) moves the clutch (212) of the torque converter to the engaged position in response to determining that the vehicle speed exceeds the vehicle speed threshold.
  15. 15. A computer program which, when executed, causes at least one processor to perform the method of any of claims 9-14.

Description

Rotor lock prevention system for electric vehicle and related method Technical Field The present disclosure relates generally to vehicles and, more particularly, to a rotor lock prevention system and related methods. Background Electric Vehicles (EVs) employ an electric motor or electric machine to apply torque to rotate the wheels of the electric vehicle. However, electric vehicles may be limited in application (e.g., off-road applications, hitching applications, etc.) due to rotor lock torque (LRT) characteristics of the electric motor. Disclosure of Invention Rotor lock-up torque (also referred to as starting torque) is the torque (e.g., maximum torque) produced by an electric motor when the rotor of the motor is stationary and full power or torque demand is commanded. For example, the rotor lock torque is an initial torque generated by the motor when the motor or vehicle starts rotating from a stationary or initial position. Accordingly, the electric vehicle started from the rest position can generate the maximum torque corresponding to the rotor lock torque characteristic of the electric motor. For this reason, electric vehicles may be limited in certain applications where the motor needs to start under loads exceeding the rotor locking torque. As a result of the rotor lock torque limit, electric vehicles employing electric motors may experience reduced motor performance at low speeds and/or when starting from a stationary position (e.g., vehicle speed is zero). At low or zero vehicle speeds, the electric motor may not generate enough torque to overcome the load or obstacle if the voltage supplied to the motor is insufficient. In some examples, motor performance degradation may occur when the vehicle is at zero speed, when the vehicle is attempting to overcome an obstacle in the vehicle path, when the vehicle is pulling weight, when the vehicle is traveling on an inclined road or sloped path (e.g., a ramp greater than 20 degrees), or is stationary. When the electric motor stalls, the motor typically continues to draw maximum current. In some cases, at motor stall, the motor does not generate back electromotive force (EMF), resulting in maximum power consumption, which may reduce battery life of the electric vehicle. Thus, for off-road applications, tow applications, traveling on a ramp (e.g., an incline of about 20 degrees or more), and/or over other obstacles in the vehicle path, the electric vehicle may experience reduced performance. Some electric vehicle manufacturers increase the inverter (e.g., the power capacity of the inverter) of the electric vehicle to reduce stall problems due to rotor locking torque. However, increasing the power capacity of the inverter results in an increase in complexity associated with integrating and/or modifying the electrical system of the electric vehicle to manage the increased power capacity of the inverter. Thus, employing a larger inverter may require more space and increase the weight of the vehicle, which may affect (e.g., degrade or reduce) the overall performance and efficiency of the vehicle (e.g., single-charge range of the vehicle). In some cases, a larger motor having a larger rotor lock torque characteristic may be employed. However, this approach adds significantly to the weight and/or consumes a greater amount of power, thereby reducing the overall mileage/battery charging cycle of the vehicle. Examples disclosed herein enhance handling by reducing or preventing rotor lock and/or motor stall conditions in an electric vehicle. To reduce or prevent a rotor lock condition, the example electric vehicles disclosed herein employ a rotor lock prevention system that detects a rotor lock condition of the vehicle. When activated, the example rotor lock prevention systems disclosed herein maintain a minimum motor speed (e.g., a minimum of 500 Revolutions Per Minute (RPM)) of the electric motor that allows or corresponds to the full torque capability of the electric motor. The example rotor lock prevention systems disclosed herein may use closed loop speed control to maintain motor speed at a speed equal to or greater than a minimum motor speed threshold (e.g., equal to or greater than 500 revolutions per minute (rpm)). When a rotor lock condition is not detected, the example rotor lock prevention system disclosed herein is deactivated, thereby reducing the inefficiencies associated with the example rotor lock prevention system. The example rotor lock-up prevention systems disclosed herein employ a transmission system that includes a fluid coupling (e.g., a torque converter) and a lock-up clutch. Specifically, the example fluid coupling disclosed herein enables slippage between an output shaft of a motor and an input or drive shaft of a transmission, thereby enabling the motor to operate at a minimum speed when the vehicle is stationary (i.e., the vehicle speed is zero). Additionally, examples disclosed herein employ a lockup clutch to activate or enable a fluid