Vehicle Brake Torque Blending Under Actuator Thermal Degradation
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Solution Overview
Problem
Conventional brake systems in electric vehicles face degradation issues due to increased temperature or voltage fluctuations, leading to reduced operability and limited availability of brake actuator functionality.
Innovation Solution
A brake device and method that utilize regenerative brake torque from an electric machine, with a controller adjusting the operation of the brake actuator to maintain a specified total brake torque by considering the electric machine's operating state and degrading the actuator's functionality adaptively, reducing power consumption and load to prolong its lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake actuator device operates at full capacity to provide sufficient brake torque, then the braking performance is improved, but the thermal load and power consumption increase leading to degradation
Solution Approach 1:
The patent combines the brake actuator device with the electric machine (motor/generator) to create an integrated braking system. The electric machine's generator mode is merged with the mechanical brake actuator, allowing the system to utilize regenerative braking capability while reducing the load on the brake actuator device itself, thereby lowering thermal load and improving reliability.
Solution Approach 2:
The controller dynamically adjusts the operating parameters of the brake actuator device based on the electric machine's current state (temperature, voltage, rotational speed). When the electric machine can provide sufficient regenerative brake torque, the brake actuator's output is reduced or deactivated, changing its operational parameters to minimize thermal load and power consumption while maintaining required braking performance.
2Reliability
If the brake actuator device is operated continuously at high power, then the braking effectiveness is maintained, but the lifetime of the brake actuator device is reduced
Solution Approach 1:
The system implements dynamic operation of the brake actuator device, where the controller continuously adjusts the actuator's output based on real-time conditions of the electric machine. The brake actuator operates dynamically between full capacity, partial capacity, and deactivated states, rather than continuously at high power, thereby extending its operational lifetime while maintaining braking effectiveness when needed.
Solution Approach 2:
The electric machine acts as an intermediary between the driver's braking request and the brake actuator device. When regenerative braking is sufficient, the electric machine mediates the braking requirement, reducing the need for mechanical brake actuator engagement and thereby extending its lifetime while maintaining overall braking effectiveness.
3Duration of action of moving object
If the brake actuator device is degraded to reduce power consumption, then the lifetime is prolonged, but the braking performance is reduced
Solution Approach 1:
The braking system is designed with multi-functionality, where the electric machine can operate in multiple modes (motor mode, generator mode, deactivated) to provide braking torque. This universality allows the system to compensate for reduced brake actuator output by increasing regenerative braking contribution, thereby maintaining overall brake torque while allowing the brake actuator to operate in a degraded, lower-power state that extends its lifetime.
Solution Approach 2:
The controller implements feedback control by continuously monitoring the electric machine's operating state and the brake actuator's condition. Based on this feedback, the controller dynamically adjusts the brake actuator's output and the electric machine's regenerative braking contribution to maintain the required total brake torque, even when the brake actuator is operated in a degraded state with reduced power consumption and extended lifetime.
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
Enhances the availability and longevity of the brake actuator by dynamically adjusting the brake torque based on the electric machine's capability, maintaining a specified deceleration level while reducing power consumption and thermal load, thus improving the brake system's reliability and efficiency.
Implementation Method 1
an electric machine in generator mode and a second brake torque, which can be generated by the electric machine
Data Source
AI summary
A brake device for a vehicle. The brake device includes a controller, which is connected to a brake actuator device. The controller is configured to ascertain an operating state of an electric machine in generator mode and a second brake torque, which can be generated by the electric machine, and to operate the brake actuator device in generator mode as a function of the operating state. A specified total brake torque on the vehicle can be generated as the sum of the second brake torque and a first brake torque of the brake actuator device. The controller is configured to reduce or increase the generated first brake torque of the brake actuator device to maintain a specified value range of an operating parameter of the brake actuator device and/or to provide, together with the second brake torque, at least the specified total brake torque on the vehicle.