Vehicle Brake Control Using Regenerative Torque After Booster Failure
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Solution Overview
Problem
Conventional brake systems for electric vehicles may fail or be restricted during operational faults, leading to inadequate braking performance and potential deactivation of the generator, compromising driving stability and energy recovery.
Innovation Solution
A brake control device that utilizes the electric machine as a generator to generate regenerative braking torque, in conjunction with a hydraulic brake system, to ensure robustness against faults in the brake booster and ESP systems, by using the ESP pump for additional hydraulic pressure and reducing the load on the ESP, thereby improving NVH and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake booster device fails or is restricted during operation, then the braking performance deteriorates and the generator may be deactivated, but the patent introduces a control device that activates the generator as a fallback braking mechanism to maintain braking performance
Solution Approach 1:
The control device is pre-configured with fallback logic that automatically activates the generator as a braking mechanism when brake booster failure is detected. This preliminary preparation ensures that braking performance is maintained without requiring real-time system reconfiguration, resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The control device acts as an intermediary between the brake booster failure detection and the generator activation. It mediates the transition by processing failure signals and triggering the generator to provide braking torque, thereby maintaining braking performance while adapting to the changed system state.
2Reliability
If the ESP pump is used extensively to build up brake pressure during HBC operation, then braking performance is maintained, but the load on the ESP increases and NVH performance deteriorates
Solution Approach 1:
The patent replaces the mechanical ESP pump-based braking system with an electric generator-based braking system. The generator directly converts kinetic energy to electrical energy while providing regenerative braking, eliminating the need for mechanical pump operation and thereby reducing NVH while maintaining braking performance.
Solution Approach 2:
The control device changes the operating parameters by activating the generator instead of relying on the ESP pump. This parameter change shifts the braking mechanism from hydraulic pressure building to electromagnetic torque generation, reducing mechanical stress and NVH while maintaining effective braking.
3Reliability
If the generator is consistently used as a fallback braking mechanism, then robustness against double faults is improved and energy recovery efficiency increases, but the complexity of coordinating multiple braking systems increases
Solution Approach 1:
The generator is designed to serve multiple functions: primary drive operation and fallback braking mechanism. This multi-functionality allows the same component to provide both propulsion and braking, simplifying the overall system architecture while improving robustness against brake booster and ESP failures.
Solution Approach 2:
The generator serves itself by providing both drive power and braking function. When activated for braking, it automatically converts kinetic energy to electrical energy, providing both deceleration and energy recovery without requiring separate systems, thereby reducing overall system complexity while improving reliability.
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 braking performance and robustness during faults, reduces brake dust generation, and maintains efficient energy recovery by leveraging the electric machine's capability to generate regenerative braking torque, even after a brake booster failure, while minimizing ESP load and improving NVH.
Implementation Method 1
the control device is designed to forward a command for a braking action by the driving stability system to the electric machine, thereby prompting it to generate a regenerative braking torque
Implementation Method 2
a regenerative brake and/or a hydraulic brake can be activated by pressing the brake pedal
Data Source
AI summary
A brake control device for a vehicle. The brake control device includes a control device, which can be connected to a brake booster device, to an electric machine of the vehicle, and to a driving stability system; a pedal sensor device, which is connected to the control device, wherein the control device is configured to infer, from the pressing of the brake pedal and/or the gas pedal, a braking request from a driver, to identify an operational failure or an operational fault of the brake booster device, and, if an operational failure or an operational fault of the brake booster device is identified after and/or upon a braking request, to control a braking action by means of the driving stability system.