Electric Vehicle Creep Torque Offset for Regenerative Braking
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Solution Overview
Problem
Electric vehicles experience energy loss due to hydraulic braking, which decreases energy recovery through regenerative braking, especially in low-speed driving conditions like congestion and slow-down sections, as the hydraulic braking force offsets the acceleration force generated by creep torque.
Innovation Solution
A system and method that apply an offset torque to the basic creep torque line in a negative direction, allowing for increased regenerative braking by varying the creep torque based on driver input, thereby minimizing energy loss and enhancing acceleration sensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydraulic braking force is increased to decelerate the vehicle, then deceleration performance is improved, but energy recovery amount by regenerative braking is decreased
Solution Approach 1:
The patent changes the parameter of creep torque by applying an offset torque to shift the basic creep torque line in the negative torque direction. This allows the vehicle to operate at a lower creep torque level, enabling increased regenerative braking without compromising deceleration performance, thereby improving energy recovery amount.
2Ease of operation
If hydraulic braking is frequently operated in low-speed driving conditions, then stopping control is improved, but energy loss increases due to offsetting creep torque
Solution Approach 1:
The patent applies an offset torque to shift the creep torque line in the negative direction, which reduces the magnitude of creep torque in low-speed conditions. This allows hydraulic braking to be more effective without being offset by excessive creep torque, improving stopping control while reducing energy loss through increased regenerative braking utilization.
3Loss of energy
If offset torque line is shifted in negative torque direction to increase regenerative braking, then energy recovery is improved, but acceleration sensation of driver may be affected
Solution Approach 1:
The patent dynamically adjusts the offset torque line based on driving conditions and driver preferences. The system can vary the degree of offset torque application to balance energy recovery with acceleration sensation, allowing the vehicle to adapt to different traffic conditions and driver requirements.
Solution Approach 2:
The patent changes the creep torque parameter by applying offset torque, but allows this parameter to be adjusted based on driver preference and traffic conditions. This enables the system to optimize energy recovery while maintaining acceptable acceleration sensation through parameter adaptation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases energy recovery during regenerative braking, reduces driver fatigue by simplifying pedal manipulation, and provides a personalized driving experience by adjusting torque settings for specific traffic conditions, thus improving travel distance and customer satisfaction.
Implementation Method 1
The electric vehicle is operated in a regenerative braking mode in which inertial energy is recovered through power generation of the motor and is charged in the battery
Implementation Method 2
The electric vehicle is decelerated using the regenerative braking and/or hydraulic braking force by frictional force of a hydraulic braking device
Data Source
AI summary
A system and a method for controlling a torque of an electric vehicle are provided. The system includes a driving information detecting unit that detects a speed of the electric vehicle and a position of an accelerator pedal and a controller that applies an offset torque input from a driver to a basic creep torque line set for creep driving of the electric vehicle to set an offset torque line varied from the basic creep torque line in a negative (−) torque direction. Additionally, the controller calculates a basic creep torque depending on the speed of the electric vehicle based on the basic creep torque line when the offset torque is not input and calculates a driver creep torque depending on the speed of the electric vehicle based on the offset torque line when the offset torque is input.