Creep Torque Control for Electric Powertrains
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Solution Overview
Problem
Vehicles with electric powertrains face inefficiencies due to uncontrolled creep torque, which consumes energy and reduces overall efficiency by opposing brake torque, especially in scenarios where the vehicle is stationary and the driver intends to remain still.
Innovation Solution
A system and method that utilize brake signals and speed sensors to determine when creep torque should be reduced, incorporating a control unit to manage and manipulate brake torque to efficiently control creep torque, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If creep torque is supplied in an electric powertrain to simulate conventional vehicle driving experience, then the vehicle can creep forward from stopped position, but energy consumption increases and overall efficiency decreases
Solution Approach 1:
The system dynamically adjusts creep torque based on real-time detection of brake pedal status and vehicle motion state. When the brake pedal is released and the vehicle is stationary, creep torque is activated to enable forward movement. When the brake pedal is pressed or the vehicle is already moving, creep torque is reduced or deactivated. This dynamic control eliminates unnecessary energy consumption while preserving the desired driving experience.
Solution Approach 2:
The control system continuously monitors brake pedal position and vehicle speed, using this feedback to determine when creep torque should be applied or reduced. The system detects the driver's intent through brake pedal status and adjusts creep torque accordingly, creating a closed-loop control that optimizes energy usage while maintaining operational effectiveness.
2Speed
If creep torque is continuously supplied without control mechanisms, then the vehicle can maintain motion from stopped position, but unnecessary energy is consumed opposing brake torque
Solution Approach 1:
The system transitions from continuous creep torque supply to dynamic adjustment based on real-time conditions. By monitoring brake pedal status and vehicle speed, the system activates creep torque only when the brake is released and the vehicle is stationary, and deactivates it when the brake is pressed or the vehicle is moving, thereby eliminating energy waste from opposing torques.
Solution Approach 2:
The control system periodically evaluates brake pedal position and vehicle motion state to determine whether creep torque should be maintained or reduced. This periodic assessment ensures that creep torque is applied only during appropriate intervals (when brake is released and vehicle is stationary) and reduced or deactivated during intervals when it would cause energy waste (when brake is pressed or vehicle is moving).
Data Source
AI summary
A system and method for controlling creep torque in a vehicle with an electric powertrain, like a hybrid electric vehicle (HEV). The method uses a combination of driver braking intent and other vehicle conditions, such as vehicle speed, to determine when creep torque is not needed and to reduce and/or cancel it accordingly. By reducing and/or cancelling the creep torque during periods where energy is being unnecessarily expended by the electric powertrain in order to work against the brakes, the present method is able to improve the overall efficiency of the vehicle.