US-20260124929-A1 - ROTOR LOCK PREVENTION SYSTEMS FOR ELECTRIC VEHICLES AND RELATED METHODS

Abstract

Rotor lock prevention systems and related methods are disclosed. An example apparatus includes an electric motor having an output shaft, a drive shaft to drive one or more wheels of a vehicle, a fluid torque converter to operatively couple 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 is to fluidly couple the output shaft of the electric motor and the drive shaft when the clutch is in the open position. The clutch to enable the electric motor to bypass the fluid torque converter to mechanically couple the output shaft of the electric motor and the drive shaft when the clutch is in the closed position.

Inventors

• Nicholas CHURCH
• Jonathan HAIR
• Keith Weston
• Matthew David Penne
• Brendan Francis DIAMOND

Assignees

• FORD GLOBAL TECHNOLOGIES, LLC

Dates

Publication Date

20260507

Application Date

20241106

Claims (20)

1. 1 . An apparatus comprising: an electric motor having an output shaft; a drive shaft to drive one or more wheels of a vehicle; a fluid torque converter to operatively couple the output shaft of the electric motor and the drive shaft; and a clutch movable between an engaged position and a disengaged position, the clutch to fluidly couple the output shaft of the electric motor and the drive shaft when the clutch is in the disengaged position, the clutch to enable the electric motor to bypass the fluid torque converter to mechanically couple the output shaft of the electric motor and the drive shaft when the clutch is in the engaged position.
2. 2 . The apparatus of claim 1 , wherein the clutch is to enable slip between the output shaft of the electric motor and the drive shaft when the clutch is in the disengaged position, the clutch to prevent slip between the output shaft of the electric motor and the drive shaft when the clutch is in the engaged position.
3. 3 . The apparatus of claim 1 , wherein the clutch is to enable the output shaft of the electric motor to rotate a first speed different than a second speed of the drive shaft when the clutch is in the disengaged position, the clutch to enable the output shaft of the electric motor and the drive shaft to rotate at the same speed when the clutch is in the engaged position.
4. 4 . The apparatus of claim 1 , further including a gearbox coupled between the output shaft of the electric motor and the fluid torque converter.
5. 5 . The apparatus of claim 1 , further including a gearbox coupled between fluid torque converter and the drive shaft.
6. 6 . The apparatus of claim 1 , wherein the fluid torque converter is a hydraulic torque converter.
7. 7 . The apparatus of claim 1 , wherein the fluid torque converter includes a turbine and an impeller, wherein the impeller is coupled to the output shaft of the electric motor and the turbine is coupled to the drive shaft.
8. 8 . The apparatus of claim 7 , wherein the clutch is slidably coupled to the turbine.
9. 9 . The apparatus of claim 8 , further including a valve fluidly coupled to the clutch, the valve movable between a first position and a second position; in the first position, the valve to cause the clutch to move to the engaged position to mechanically couple the output shaft of the electric motor and the drive shaft; and in the second position, the valve to cause the clutch to move to the disengaged position to fluidly couple the output shaft of the electric motor and the drive shaft.
10. 10 . The apparatus of claim 9 , further including a controller to cause the valve to move 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 including a controller to cause the valve to move to the second position and operate the electric motor at least at 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 includes at least one of a towing mode, an off-road mode, an electric motor stall, an elevated grade, or an inverter condition.
13. 13 .- 20 . (canceled)
14. 21 . An apparatus comprising: an electric motor having an output shaft; a drive shaft operatively coupled to a wheel of a vehicle; a fluid coupling interposed between the output shaft and the drive shaft, the fluid coupling to couple the output shaft of the electric motor and the drive shaft, the fluid coupling having a lock-out clutch movable between an engaged position and a disengaged position, the fluid coupling mechanically coupling the output shaft of the electric motor and the drive shaft when the lock-out clutch is in the engaged position, and the fluid coupling fluidly coupling the output shaft and the drive shaft to permit slip between the output shaft and drive shaft when the lock-out clutch is in a disengaged position.
15. 22 . The apparatus of claim 21 , further including a control unit that, based on a sensed vehicle speed and a motor torque command, actuates the lock-out clutch to maintain a motor speed above a predetermined motor-speed threshold to prevent rotor lock of the electric motor.
16. 23 . An apparatus comprising: an electric motor having an output shaft; a drive shaft operatively coupled to a wheel of a vehicle; a fluid coupling including a turbine, an impeller and a stator; a lock-out clutch slidably coupled to the turbine of the fluid coupling; and a controller operably connected to the lock-out clutch, the controller to actuate the lock-out clutch between an engaged position in which the fluid coupling mechanically couples the output shaft of the electric motor and the drive shaft, and a disengaged position in which the fluid coupling fluidly couples the output shaft and the drive shaft to permit slip.
17. 24 . The apparatus of claim 23 , further including a gearbox coupled between the electric motor and the fluid coupling.
18. 25 . The apparatus of claim 23 , wherein the fluid coupling is a hydraulic torque converter.
19. 26 . The apparatus of claim 23 , wherein the impeller is coupled to the output shaft of the electric motor and the turbine is coupled to the drive shaft.
20. 27 . The apparatus of claim 26 , wherein the lock-out clutch is slidably coupled to the turbine.

Description

FIELD OF THE DISCLOSURE This disclosure relates generally to vehicles and, more particularly, to rotor lock prevention systems and related methods. BACKGROUND Electric vehicles (EVs) employ electric motors or electric machines to apply torque to rotate wheels of the electric vehicles. However, electric vehicles can be limited in applications (e.g., off-road applications, towing applications, etc.) due to rotor lock torque (LRT) characteristics of electric motors. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an example vehicle in which examples disclosed herein can be implemented. FIG. 2 is a schematic illustration of the example vehicle of FIG. 1 having an example rotor locking prevention system in accordance with teachings of this disclosure. FIG. 3A is a side, partial cutaway view of an example fluid coupling of FIG. 2 with an example lock-out clutch in an example open position. FIG. 3B is a side, partial cutaway view of the example fluid coupling of FIG. 3A with the example lock-out clutch in an example open position. FIG. 4 is a block diagram of an example implementation of an example rotor lock prevention control circuitry of FIG. 2. FIGS. 5-8 are flowcharts representative of example machine readable instructions and/or example operations that may be executed, instantiated, and/or performed by example programmable circuitry to implement the example rotor lock prevention control circuitry of FIG. 4. FIG. 9 is a block diagram of an example processing platform including programmable circuitry structured to execute, instantiate, and/or perform the example machine readable instructions and/or perform the example operations of FIGS. 5-8 to implement the example rotor lock prevention control circuitry of FIG. 4. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. The figures are not necessarily to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. Although the figures show layers and regions with clean lines and boundaries, some or all of these lines and/or boundaries may be idealized. In reality, the boundaries and/or lines may be unobservable, blended, and/or irregular. DETAILED DESCRIPTION Rotor lock torque, also known as starting torque, is a torque (e.g., a maximum torque) that an electric motor produces when a rotor of the motor is stationary and full power or torque demand is commanded. For example, rotor lock torque is an initial torque generated by a motor when the motor or vehicle starts rotating from a standstill or initial position. Thus, an electric vehicle starting from a standstill position can produce a maximum torque corresponding to the rotor lock torque characteristic of the electric motor. To this end, electric vehicles can be limited in certain applications where a motor needs to start under load that exceeds the rotor lock torque. As a result of rotor lock torque limitations, electric vehicles employing electric motors can experience reduced motor performance at low speeds and/or when starting from a standstill position (e.g., a vehicle speed of zero). At low or zero vehicle speeds, an electric motor may not generate enough torque to overcome a load or obstacle if a voltage supplied to the motor is insufficient. In some examples, when the vehicle speed is zero, reduced motor performance can occur when the vehicle is attempting to overcome an obstacle in the vehicle's path, is towing weight, the vehicle is traveling or is at a standstill on an inclined road or graded path (e.g., a grade of greater than 20 degrees). When an electric motor stalls, the motor typically continues to draw maximum current. In some instances, at motor stall, a motor does not generate back electromotive force (EMF), resulting in maximum power consumption, which can reduce battery range of the electric vehicle. Thus, electric vehicles may experience reduced performance for off-road applications, towing applications, traveling on a grade (e.g., an incline of approximately 20 degrees or greater), and/or traversing other obstacles in the vehicle's path. Some electric vehicle manufacturers upsize an inverter (e.g., a power capacity of an inverter) of the electric vehicle to reduce stall issues due to rotor lock torque. However, upsizing a power capacity of an inverter leads to increased complexity associated with integrating and/or modifying an electrical system of the electrical vehicle to manage the upsized power capacity of the inverter. Thus, employing larger inverters can require more space and add weight to the vehicle, which could affect (e.g., degrade or decrease) overall performance and efficiency of the vehicle (e.g., a single charge range of the vehicle). In some instances, a larger sized motor having greater rotor lock torque characteristics can be employed. However, such an approach significantly increases weight and/or consumes a greater amount of pow