Hybrid Vehicle Braking Torque Control for Stability and Energy Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Regenerative braking in electric or hybrid vehicles can lead to stability issues, especially during emergency braking, as existing systems do not effectively manage vehicle stability and energy recovery simultaneously.
Innovation Solution
A method and system that determine and manage hydraulic and electric braking torque setpoints based on driver input, vehicle stability information, and adaptive assistance systems to optimize braking and energy recovery, including the selection of the highest torque setpoint and independent hydraulic braking torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is activated to recover electrical energy, then energy recovery is improved, but vehicle stability deteriorates during emergency braking
Solution Approach 1:
The braking system is segmented into two independent control pathways: a driver-initiated hydraulic braking pathway and an stability-controlled regenerative braking pathway. The electronic stability control system can independently manage regenerative braking torque without being constrained by driver pedal input, allowing energy recovery to be activated or deactivated based on stability requirements rather than direct mechanical linkage.
Solution Approach 2:
An electronic control unit acts as an intermediary between the driver's braking request and the actual braking torque application. This intermediary can decouple the driver's pedal input from the final braking torque distribution, allowing the system to optimize energy recovery while maintaining stability by independently adjusting regenerative and hydraulic braking components based on real-time stability feedback.
2Ease of operation
If direct mechanical link between brake pedal and braking member is maintained, then ease of operation is improved, but ability to manage stability and energy recovery simultaneously deteriorates
Solution Approach 1:
The direct mechanical linkage between the brake pedal and braking members is replaced with an electronic control system. The brake pedal remains as a simple input device for the driver, while electronic sensors and control algorithms manage the complex distribution of hydraulic and regenerative braking torque, enabling advanced stability control and energy recovery management without increasing operational complexity for the driver.
3Loss of energy
If regenerative braking torque is maximized for energy recovery, then energy recovery is improved, but braking effectiveness deteriorates when hydraulic braking is needed
Solution Approach 1:
The system dynamically adjusts the distribution of braking torque between regenerative and hydraulic systems based on real-time vehicle conditions, stability requirements, and energy recovery opportunities. The electronic stability control can rapidly modulate regenerative braking torque levels, transitioning between maximum energy recovery mode and stability-priority mode, ensuring optimal performance across varying operating conditions.
Solution Approach 2:
The control system changes key parameters including regenerative braking torque magnitude, hydraulic braking torque distribution, and energy recovery activation status based on vehicle stability state, driver intent, and battery charge level. These parameter adjustments allow the system to maximize energy recovery when safe and provide full hydraulic braking capability when stability or braking effectiveness is prioritized.
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 maximizes energy recovery while minimizing vehicle instability and ensures effective braking by decoupling braking actions from driver input, allowing for stable and efficient deceleration strategies.
Implementation Method 1
braking can be carried out by a braking actuator, for example hydraulic, or by the electric traction actuator which, in regenerative mode, allows recovery of electrical energy which can be stored in the batteries
Data Source
Figure 1~3
AI summary
Braking method for a motor vehicle fitted with a hybrid or electric propulsion system and comprising a hydraulic braking system, an electric braking system for recuperating electrical energy, a brake pedal, systems to assist with the driving of the vehicle, a vehicle electronic stability control system, the method comprising the following steps: - selection of one of the torque setpoints from between a pedal torque setpoint (c_pedal) relating to the position of or the force supplied to the brake pedal, and a torque setpoint relating to the driver assistance systems (c_assist), formulation of a hydraulic braking torque setpoint (c_sub) independent of the state of the pedal by the electric or hybrid propulsion system, - acquisition of information (d_stability) relating to the stability of the vehicle, formulation of a hydraulic braking torque setpoint (c_hyd_br) and of an electric braking torque setpoint (c_elec_br) intended for the hybrid or electric propulsion system on the basis of the selected torque setpoint (c_sel), of the independent hydraulic braking torque setpoint (c_sub) and the information relating to the stability of the vehicle (d_stability).