Regenerative Braking Torque Control During Wheel Slip
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Solution Overview
Problem
Hybrid electric vehicles experience a temporary reduction in overall braking torque during wheel slip events due to abrupt transition from regenerative braking to friction braking, which can be detrimental, especially on surfaces with high friction coefficients during high deceleration events like Collision Mitigation by Brakes.
Innovation Solution
A system and method that inhibit regenerative braking torque reduction by interfacing an antilock braking system with a regeneration powertrain, using ABS active signals to maintain continuous braking torque during high deceleration events, ensuring seamless transition between regenerative and friction braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative braking is abruptly removed during a wheel slip event, then wheel lockup is minimized on low friction surfaces, but overall braking torque is temporarily reduced causing delayed braking response
Solution Approach 1:
The system dynamically adjusts the regenerative braking torque reduction rate based on detected driving conditions. During CMbB events, the reduction rate is slowed or prevented to maintain braking torque. During normal ABS events on low-friction surfaces, the reduction rate is accelerated to prevent wheel lockup. This dynamic adaptation resolves the contradiction by optimizing the regenerative braking transition for different operational contexts.
Solution Approach 2:
The control system changes the parameter of regenerative braking torque reduction rate based on detected event types. By identifying whether an ABS event occurs during a CMbB event or normal braking, the system adjusts the torque reduction parameter accordingly - maintaining high torque during CMbB events while allowing rapid reduction during normal events to prevent wheel lockup.
2Reliability
If regenerative braking torque is rapidly reduced during ABS events, then wheel lockup is prevented on low friction surfaces, but braking torque continuity is disrupted
Solution Approach 1:
The system implements dynamic control of regenerative braking torque reduction based on real-time detection of ABS event context. During CMbB events, the reduction is slowed or inhibited to maintain torque continuity. During normal ABS events, rapid reduction is permitted to control wheel slip. This dynamic approach maintains braking torque continuity when needed while allowing rapid adjustment when wheel slip control is the priority.
3Stability of the object's composition
If regenerative braking is maintained during wheel slip events, then braking torque continuity is improved, but wheel lockup risk increases on low friction surfaces
Solution Approach 1:
The system changes the regenerative braking torque parameter based on detected event conditions. During CMbB events, the torque is maintained at high levels to ensure braking continuity. During normal ABS events on low-friction surfaces, the torque is rapidly reduced to prevent wheel lockup. This parameter adaptation resolves the contradiction by optimizing torque levels for different operational contexts.
Data Source
AI summary
A system for controlling regenerative braking in an electrified vehicle to prevent or minimize reduction of overall braking torque during wheel slip events includes an antilock braking system adapted to transmit an antilock braking system active signal and a regeneration powertrain interfacing with the antilock braking system. The regeneration powertrain is adapted to inhibit regenerative braking torque reduction responsive to receiving the antilock braking system active signal during a high deceleration braking event. A method for controlling regenerative braking in an electrified vehicle to prevent or minimize reduction of overall braking torque during wheel slip events is also disclosed.