EV Braking Torque Control for Long Downhill Heat Management
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Solution Overview
Problem
Battery electric vehicles face brake failure due to excessive heat generated during long and steep downhill driving, as driver control over engine braking is absent, leading to inadequate braking strategies.
Innovation Solution
A control system and method that calculates total braking torque, determines available regenerative and mechanical braking torques, and applies them to maintain safe vehicle velocity, using a controller to coordinate regenerative and mechanical braking systems, alerting the driver and adjusting braking torque application as necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical braking is used continuously during long downhill driving, then the vehicle can maintain controlled velocity, but excessive heat is generated causing brake failure
Solution Approach 1:
The patent combines regenerative braking and mechanical braking systems into a unified braking strategy. The controller coordinates both systems to share the braking workload, allowing regenerative braking to handle a portion of the deceleration demand while mechanical braking provides the remainder, thereby reducing thermal load on mechanical brakes while maintaining effective velocity control during downhill driving
Solution Approach 2:
The patent dynamically adjusts the distribution of braking torque between regenerative and mechanical systems based on real-time conditions such as battery state of charge, braking intensity requirements, and thermal status. By changing the parameter of braking torque allocation, the system optimizes the use of regenerative braking capacity while preventing mechanical brake overheating
2Temperature
If regenerative braking torque is increased to reduce mechanical brake usage, then brake heat is reduced, but braking control precision may be compromised
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors braking performance, vehicle velocity, and system status. Based on this feedback, the controller dynamically adjusts the torque distribution between regenerative and mechanical braking systems, ensuring that the total braking torque meets the required deceleration demand while maintaining optimal thermal management and braking control precision
3Use of energy by moving object
If driver control over engine braking is removed in electric vehicles, then electric motor efficiency is improved, but braking strategy complexity increases
Solution Approach 1:
The patent implements an autonomous braking control system that automatically manages torque distribution between regenerative and mechanical braking without requiring direct driver intervention. The controller independently calculates optimal torque allocation based on real-time vehicle conditions, battery state, and braking demands, thereby maintaining motor efficiency while managing the complexity of coordinated braking through automated decision-making algorithms
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
Prevents brake failure by effectively managing braking torque distribution between regenerative and mechanical systems, ensuring safe vehicle speed and preventing overheating during downhill driving.
Implementation Method 1
An available regenerative braking torque of the electric vehicle is determined
Implementation Method 2
excessive heat generated by braking during a long and steep downhill grade
Data Source
AI summary
An electric vehicle, and braking system and a method of operating the electric vehicle. The braking system includes a mechanical braking system, a regenerative braking system, and a controller. The controller is configured to calculate a total braking torque for operating the electric vehicle at a selected velocity during braking, determine an available regenerative braking torque via the regenerative braking system, calculate a mechanical brake torque for the mechanical braking system from the total braking torque and the available regenerative brake torque, and apply the mechanical brake torque at the mechanical braking system.