Friction Brake Thermal Management for Vehicle Grade Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vehicle systems operating at light load and low speed for extended periods, especially those with advanced propulsion systems, experience component overheating due to inefficient cooling systems that rely on vehicle speed.
Innovation Solution
A vehicle system with a propulsion system and friction brake, controlled by a controller that monitors vehicle speed, grade, and operator requests, applies braking torque to maintain desired speeds and release brakes when an operator acceleration request exceeds a minimum grade-based request, ensuring effective heat rejection and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the vehicle operates at low speed for extended periods on a grade, then the vehicle can maintain position or move slowly, but the propulsion system components overheat due to insufficient cooling
Solution Approach 1:
The patent replaces the traditional mechanical cooling system (liquid-based cooling dependent on vehicle speed) with a thermal management system that uses the friction brake as a heat sink. The brake absorbs excess heat from the propulsion system through thermal conduction, allowing the vehicle to operate at low speeds without component overheating.
Solution Approach 2:
The friction brake serves as an intermediary thermal management device between the propulsion system and the environment. Instead of relying on air flow from vehicle motion to cool components, the brake acts as a mediator that actively absorbs and dissipates heat through friction, enabling thermal management independent of vehicle speed.
2Temperature
If the friction brake is used to maintain vehicle speed on a grade, then heat rejection is improved, but the brake wear increases
Solution Approach 1:
The control system implements periodic or intermittent brake application rather than continuous braking. The brake is applied only when thermal management is needed (when the propulsion system generates excess heat), and released when thermal equilibrium is achieved, thereby reducing cumulative brake wear while maintaining effective heat rejection capability.
3Use of energy by moving object
If the vehicle uses advanced propulsion systems with speed-dependent cooling, then fuel efficiency is improved, but the cooling effectiveness deteriorates at low speeds
Solution Approach 1:
The friction brake, which would normally only serve to slow or stop the vehicle, is made to serve a dual function by absorbing heat from the propulsion system. This self-service approach allows the brake to contribute to thermal management, enabling the vehicle to maintain fuel efficiency through advanced propulsion systems without sacrificing cooling effectiveness at low speeds.
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
The system effectively prevents component overheating by managing vehicle speed and torque to maintain efficient heat rejection, reducing the need for liquid-based cooling systems and minimizing low-speed creep operations, thus enhancing thermal robustness and operational reliability.
Implementation Method 1
a friction brake configured to apply braking torque to the drive wheel
Implementation Method 2
component cooling is achieved by cooling systems that are dependent on vehicle speed
Data Source
AI summary
A vehicle system including a propulsion system coupled to a drive wheel and a friction brake configured to apply braking torque to a vehicle wheel is described. Operation thereof includes an instruction set that is executable to monitor vehicle speed, vehicle grade, and an operator braking request, and execute instructions upon achieving a vehicle speed that is less than a threshold speed. The instructions include controlling, via the friction brake, the braking torque to achieve a desired vehicle speed, and determining an operator acceleration request and the vehicle grade. The controller determines a minimum vehicle grade-based operator acceleration request, and releases the friction brake only when the operator acceleration request is greater than the minimum vehicle grade-based operator acceleration request.