Vehicle Powertrain Braking Torque Split for Stable Regeneration
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Solution Overview
Problem
Hybrid and electric vehicles face challenges in achieving stable braking performance while maximizing regenerative braking, which is essential for improving fuel efficiency, without relying on expensive and complex devices.
Innovation Solution
A powertrain configuration incorporating a motor, planetary gear set, and braking control method that distributes braking torque between front and rear wheels using a controller-generated braking torque distribution map, allowing for efficient regenerative and friction braking, thereby enhancing energy recovery and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is maximized to improve fuel efficiency, then energy recovery rate increases, but braking performance stability deteriorates
Solution Approach 1:
The braking system is segmented into two independent parts: regenerative braking mechanism and friction braking mechanism. The controller distributes total braking torque between these two mechanisms based on real-time conditions, allowing the vehicle to maximize energy recovery while maintaining stable braking performance through the complementary friction braking system.
2Reliability
If expensive complicated devices are mounted to secure stable braking performance, then braking performance stability improves, but vehicle cost increases
Solution Approach 1:
The motor serves multiple functions: propulsion during acceleration and regenerative braking during deceleration. The planetary gear set, originally designed for power transmission, is utilized to enable friction braking through mechanical connection. This multi-functionality approach allows the vehicle to achieve stable braking performance without requiring additional expensive dedicated braking components.
3Reliability
If friction braking is used to maintain stable braking performance, then braking performance stability improves, but energy recovery rate decreases
Solution Approach 1:
The controller dynamically adjusts the distribution of braking torque between regenerative and friction braking mechanisms based on real-time vehicle conditions, road surface state, and braking intensity requirements. This dynamic adjustment allows the system to maximize energy recovery during conditions favorable for regenerative braking while seamlessly transitioning to friction braking when stability is prioritized, optimizing both energy recovery and braking performance throughout the braking process.
Data Source
AI summary
A powertrain for a vehicle may include a motor; a planetary gear set mounted to rotate parallel to a rotation shaft of the motor so that one rotation element may exchange power with the motor; a front wheel driveshaft engaged to the planetary gear set to receive power from another rotation element of the planetary gear set and to transfer a rotating force to a front wheel coupled to the front wheel driveshaft; and a rear wheel driveshaft engaged to the planetary gear set and mounted to receive power from the other rotation element of the planetary gear set to rotate parallel to the rotation shaft of the motor, and to transfer a rotating force to a rear wheel coupled to the rear wheel driveshaft.