Dynamic Regenerative Braking Torque Split for Electric Vehicles
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Solution Overview
Problem
Existing vehicle braking systems, particularly in electric vehicles, fail to optimize regenerative braking due to a fixed front to rear traction balance, which does not adapt to changing vehicle operating conditions such as suspension orientation and load distribution.
Innovation Solution
The system adjusts braking torque applied to the front and rear axles using sensors that measure normal loads and suspension height, dynamically compensating for changes in vehicle mass and suspension orientation to optimize regenerative braking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed proportioning valve is used to allocate braking force to front and rear wheels, then the braking system is simple to manufacture and operate, but the regenerative braking efficiency deteriorates because the front to rear traction balance cannot adapt to changing vehicle operating conditions
Solution Approach 1:
The system dynamically adjusts the braking torque distribution between front and rear axles based on real-time sensor feedback regarding vehicle operating conditions. The controller continuously modifies the regenerative braking torque applied to each axle to maintain optimal front-to-rear traction balance, transitioning from a static fixed-ratio system to a dynamic adaptive system that responds to changing conditions such as acceleration, deceleration, and load distribution.
Solution Approach 2:
The system implements a feedback control mechanism where sensors monitor vehicle operating conditions including axle normal loads and suspension orientation, and this information is fed back to the controller which adjusts the regenerative braking torque distribution accordingly. This closed-loop control enables the system to adapt to changing conditions and optimize regenerative braking efficiency while maintaining traction balance.
2Reliability
If regenerative braking torque is limited to maintain front to rear traction balance, then wheel slip is reduced, but the overall regenerative braking efficiency deteriorates because the braking torque cannot be optimized for varying normal loads
Solution Approach 1:
The system changes the braking torque parameters dynamically based on measured normal loads and suspension orientation. By adjusting the regenerative braking torque distribution between front and rear axles according to real-time conditions, the system optimizes the utilization of available traction at each axle, thereby improving overall regenerative braking efficiency while maintaining appropriate front-to-rear balance to prevent wheel slip.
Solution Approach 2:
The system applies different regenerative braking torque levels to the front and rear axles based on their respective normal loads and traction conditions. Each axle receives a customized braking torque that is optimized for its local conditions, allowing the rear axle to potentially receive higher torque when rear normal load is high, while the front axle receives torque appropriate for its load conditions, thereby maximizing overall energy recovery.
3Device complexity
If the braking torque split is fixed regardless of suspension orientation, then the control system is simple, but the regenerative braking performance deteriorates when vehicle mass or suspension orientation changes
Solution Approach 1:
The control system uses feedback from sensors that measure suspension orientation and axle normal loads to dynamically adjust the regenerative braking torque distribution. This feedback mechanism allows the system to adapt to changes in vehicle mass and suspension orientation without requiring a completely complex control architecture, as the adjustments are made automatically based on measured conditions rather than requiring complex predictive models.
Solution Approach 2:
The control system is designed to handle multiple functions: it monitors suspension orientation, calculates normal loads, determines optimal braking torque distribution, and controls both regenerative and friction braking. By integrating these functions into a single adaptive control system, the patent achieves improved regenerative braking performance across varying conditions while keeping the overall system manageable through unified control logic.
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 enhances regenerative braking efficiency by dynamically adjusting the braking torque split based on real-time axle load and suspension conditions, improving traction and reducing the likelihood of wheel slip.
Implementation Method 1
Hybrid vehicles and electric vehicles may provide regenerative braking via an electric machine that slows the vehicle by converting the vehicle's kinetic energy into electric energy
Implementation Method 2
The vehicle may be stopped via friction brakes
Data Source
AI summary
Methods and system are provided for generating regenerative braking torque at a front axle and a rear axle of a vehicle. In one example, the regenerative braking torque may be a function of a normal load applied to the front axle and a normal load applied to the rear axle.