Regenerative Brake Torque Distribution for Vehicle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid electric vehicles (HEVs) face challenges in balancing brake torque between front and rear wheels during regenerative braking, affecting vehicle stability due to energy collection from only one axle, which can lead to uneven traction and instability.
Innovation Solution
A regenerative brake control system for four-wheel drive vehicles that uses a vehicle controller, driveline torque distribution device, and electric machine to apportion regenerative brake torque proportionally to each wheel based on traction coefficients, ensuring balanced torque distribution and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If regenerative braking collects energy from one axle only, then energy collection is simplified and component requirements are reduced, but brake torque balance between front and rear wheels is compromised and vehicle stability deteriorates
Solution Approach 1:
The regenerative braking system is segmented to collect energy from both front and rear axles independently through separate electric machines, rather than collecting from only one axle. This segmentation allows balanced torque distribution while maintaining manageable system complexity through modular architecture
Solution Approach 2:
The system applies local quality by independently controlling regenerative torque at each axle based on local traction conditions. The front and rear axles can have different regenerative braking characteristics optimized for their respective traction environments, improving overall vehicle stability
2Device complexity
If regenerative braking is implemented without proportional torque apportionment, then control system complexity is reduced, but brake torque balance between wheels deteriorates and vehicle stability is affected
Solution Approach 1:
The control system dynamically adjusts regenerative brake torque apportionment based on real-time traction coefficients calculated for each wheel. This dynamic adaptation allows the system to maintain optimal torque distribution and vehicle stability without requiring overly complex predetermined control strategies
Solution Approach 2:
The system uses feedback from traction condition sensors and wheel speed sensors to continuously calculate traction coefficients and adjust regenerative torque distribution. This closed-loop feedback mechanism maintains vehicle stability while keeping control system complexity manageable through algorithmic optimization
3Loss of energy
If regenerative brake torque is not apportioned proportionally to traction, then energy capture may be maximized from single axle, but uneven brake torque between front and rear wheels causes instability
Solution Approach 1:
The system changes the parameter of torque apportionment ratio based on traction coefficients. By dynamically adjusting what proportion of total regenerative torque is applied to each axle according to measured traction conditions, the system simultaneously maximizes energy capture and maintains vehicle stability
Solution Approach 2:
The control system performs preliminary calculation of optimal torque apportionment based on predicted traction conditions and vehicle state. This preliminary action allows the system to proactively distribute torque in a way that maximizes energy recovery while preventing instability before it occurs
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
The system optimizes regenerative brake torque distribution across all four wheels, enhancing vehicle stability, smooth transition between friction and regenerative braking, and maximizing energy capture while maintaining desired drive characteristics.
Implementation Method 1
the regen components collect energy from one axle only such that when braking is required, the regen energy is collected
Implementation Method 2
a driveline torque distribution device, such as a variable coupler, interfacing with the vehicle controller
Data Source
AI summary
A regenerative brake control system for a vehicle includes a vehicle controller, a driveline torque distribution device interfacing with the vehicle controller, an electric machine interfacing with the driveline torque distribution device, a plurality of wheels coupled to the electric machine and at least one traction condition input indicating traction of the plurality of wheels provided to the vehicle controller. The vehicle controller engages the driveline torque distribution device and the electric machine apportions regenerative brake torque to the wheels in proportion to the traction of the wheels. A regenerative brake control method for a vehicle is also disclosed.