Coast Regeneration Torque Control for Slip Correction
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Solution Overview
Problem
Existing systems for applying coast regeneration torque in vehicles struggle to accurately control slip ratios between driving and non-driving wheels, leading to reduced energy recovery and deteriorated fuel efficiency due to excessive reduction in coast regeneration torque, especially on low-friction surfaces.
Innovation Solution
A method that detects wheel slip and calculates wheel speed differences or slip ratios, applying correction values based on predetermined reference values to adjust coast regeneration torque, thereby stabilizing vehicle stability and preventing unnecessary reduction in torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If coast regeneration torque is increased to improve energy recovery, then energy recovery factor is improved, but wheel slip occurs on low-friction surfaces deteriorating vehicle stability
Solution Approach 1:
The coast regeneration torque is dynamically adjusted based on real-time wheel speed differences and slip ratio calculations. The system continuously monitors wheel speeds and modifies torque application to maintain optimal energy recovery while preventing slip on varying road surfaces.
Solution Approach 2:
The system changes the torque parameter based on calculated slip ratios and wheel speed differences. By adjusting the coast regeneration torque parameter according to actual wheel behavior, the system optimizes energy recovery while maintaining vehicle stability on different road conditions.
2Reliability
If coast regeneration torque is reduced to prevent wheel slip, then vehicle stability is improved, but energy recovery factor and fuel efficiency are deteriorated
Solution Approach 1:
The system implements feedback control by continuously calculating wheel speed differences and slip ratios, then using this information to adjust coast regeneration torque. This closed-loop approach ensures torque is reduced only when actual slip occurs, maintaining energy efficiency while preventing instability.
Solution Approach 2:
The torque application is dynamically controlled based on real-time feedback from wheel speed sensors and slip ratio calculations, allowing the system to maintain high energy recovery on stable surfaces while automatically reducing torque only when slip is detected.
3Reliability
If wheel speed difference is used to control coast regeneration torque, then wheel slip can be prevented, but hardware-related speed differences cause unnecessary torque reduction decreasing energy recovery
Solution Approach 1:
The system performs preliminary calculation of expected wheel speed differences based on vehicle hardware characteristics before applying torque control. By anticipating hardware-related speed variations, the system avoids unnecessary torque reduction while still preventing actual slip conditions.
Solution Approach 2:
The slip ratio calculation serves as an intermediary parameter that distinguishes between hardware-related speed differences and actual slip conditions. This intermediate measurement allows the system to filter out false slip signals while maintaining accurate slip detection for genuine stability issues.
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 improves energy recovery and fuel efficiency by preventing vehicle slip and maintaining stability, even when slip occurs due to hardware-related differences in wheel speeds, without further reducing coast regeneration torque.
Implementation Method 1
the eco-friendly vehicle operates a motor and/or a starter generator as a generator to recover inertial energy
Implementation Method 2
when a friction coefficient of a road, such as a snowy road, an icy road, and a rainy road, is small, slip may occur
Data Source
AI summary
A system and method of applying a coast regeneration torque of a vehicle are provided. The method corrects a magnitude of slip (or a slip ratio) which is considered when a coast regeneration torque is to be variably controlled while the vehicle is coasting.