Regenerative Braking Torque Curves for Neutral Downhill Speed Control
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Solution Overview
Problem
Current regenerative braking systems in electric and hybrid vehicles fail to apply torque consistently with driver expectations, leading to inefficient energy recapture and unnecessary wear on service brakes, particularly during downhill driving.
Innovation Solution
A motor controller determines optimal regenerative braking torque based on predefined or dynamically defined torque curves, maintaining vehicle speed and minimizing service brake use, thereby optimizing energy recapture and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking systems apply maximum torque to maximize energy recapture, then energy recapture efficiency is improved, but vehicle stability and driver comfort deteriorate due to inconsistent torque application
Solution Approach 1:
The system dynamically adjusts regenerative braking torque based on real-time vehicle conditions (speed, acceleration, battery state of charge) rather than applying fixed maximum torque. This dynamic control allows the system to optimize energy recapture while maintaining vehicle stability and matching driver expectations across different operating scenarios.
Solution Approach 2:
The control system continuously monitors vehicle state parameters and uses this feedback to adjust regenerative braking torque in real-time. By incorporating feedback from sensors measuring vehicle speed, acceleration, and battery charge level, the system can modulate torque application to prevent instability while maximizing energy recovery under optimal conditions.
2Ease of operation
If manual torque selection is used to maintain vehicle stability, then driver comfort is improved, but energy recapture efficiency deteriorates due to suboptimal torque amounts
Solution Approach 1:
The system performs automatic torque optimization without requiring manual driver input. By implementing self-service control algorithms that autonomously determine optimal regenerative braking torque based on vehicle conditions, the system eliminates the need for driver intervention while simultaneously achieving both driver comfort and maximum energy recapture efficiency.
Solution Approach 2:
The system changes torque parameters dynamically based on operating conditions rather than using fixed manual selections. By adjusting torque magnitude, duration, and application rate according to real-time vehicle state and driver behavior patterns, the system achieves optimal energy recapture while maintaining comfort levels comparable to manual control.
3Speed
If service brakes are used to control vehicle speed during downhill driving, then vehicle speed control is improved, but brake wear and heating increase unnecessarily
Solution Approach 1:
The system replaces mechanical service brake usage with electromagnetic regenerative braking for speed control during downhill driving. By substituting the mechanical friction-based braking system with an electromagnetic motor-generator acting as a brake, the system achieves effective speed control while eliminating wear and heat generation associated with traditional service brakes.
Solution Approach 2:
The system converts the normally wasted kinetic energy during downhill braking into useful electrical energy for battery charging. By capturing the energy that would otherwise be lost as heat in service brakes and converting it to electrical energy through regenerative braking, the system simultaneously controls vehicle speed and recovers energy, turning a harmful energy loss into a beneficial resource.
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
Enhances energy recapture efficiency and reduces brake wear by automatically adjusting regenerative braking torque to match driver expectations and maintain vehicle stability.
Implementation Method 1
One form of a regenerative braking system utilizes a motor that is configured to act as a generator that converts mechanical energy generated from the braking process to electrical energy
Data Source
AI summary
A device comprises motor controller coupled to a drive motor and a battery pack of a vehicle. The motor controller comprises a processor that is configured to: determine that the vehicle is engaged in a neutral braking mode, and after determining that the vehicle is engaged in the neutral braking mode: select a neutral braking torque curve, determine a rotational velocity of the drive motor, based on the determined rotational velocity of the drive motor, determine an amount of regenerative braking torque to apply to the drive motor based on the selected neutral braking torque curve, apply the determined amount of regenerative braking torque to the drive motor, wherein applying the determined amount of regenerative braking torque to the drive motor results in a regenerative current generated by the drive motor, and supply the regenerative current to the battery pack to at least partially recharge the battery pack.