Brake Force Distribution for Regenerative Brake Cleaning
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Solution Overview
Problem
In vehicles with regenerative braking systems, the reduced use of friction brakes leads to suboptimal friction coefficients due to corrosion, affecting braking performance and requiring frequent brake replacements. Additionally, reducing regenerative braking to increase hydraulic braking results in higher fuel consumption.
Innovation Solution
A method for operating a braking system that determines the cleaning need of each wheel brake based on corrosion levels and distributes the braking force between the regenerative and friction braking systems. The method uses a sensor to determine the brake pedal position and generates a control signal for the actuator to adjust the hydraulic pressure at each wheel brake, ensuring effective cleaning and energy recuperation while maintaining a consistent brake pedal feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is used to reduce fuel consumption, then energy efficiency is improved, but friction brake cleaning is insufficient leading to corrosion and reduced braking performance
Solution Approach 1:
The system implements periodic friction brake activation at predetermined time intervals regardless of driver braking requests. This periodic action ensures that friction brakes are regularly activated to clean the friction surfaces and prevent corrosion, while the vehicle primarily uses regenerative braking for energy efficiency. The control unit schedules these cleaning operations to occur during normal vehicle operation.
Solution Approach 2:
The system proactively activates friction brakes before corrosion significantly degrades braking performance. By implementing preventive cleaning operations at scheduled intervals, the system maintains optimal friction surface conditions without waiting for performance degradation to occur, thereby preserving reliability while minimizing the need to reduce regenerative braking usage.
2Reliability
If friction brake usage is increased to clean wheel brakes, then braking performance is improved, but energy recuperation efficiency is reduced
Solution Approach 1:
Instead of continuously using friction brakes, the system employs periodic activation at predetermined time intervals. This approach provides sufficient cleaning action to maintain braking performance while minimizing the energy lost through friction, thereby preserving energy recuperation efficiency. The intermittent usage pattern balances cleaning needs with energy conservation.
Solution Approach 2:
The system applies friction brakes with sufficient force to achieve effective cleaning during periodic activation events. While the duration is limited, the intensity of each friction braking event is adequate to remove corrosion and restore optimal friction coefficients, ensuring that partial activation achieves the desired cleaning effect without excessive energy consumption.
3Reliability
If friction brakes are frequently activated for cleaning, then wheel brake cleanliness is improved, but brake wear increases
Solution Approach 1:
The system activates friction brakes at predetermined time intervals rather than continuously or on every braking opportunity. This periodic activation provides sufficient cleaning action to maintain adequate friction coefficients while significantly reducing the cumulative wear compared to frequent activation. The interval between activations is calibrated to balance cleaning effectiveness with wear reduction.
Solution Approach 2:
The friction braking system performs self-maintenance by automatically activating at scheduled intervals to clean its own friction surfaces. This self-service function maintains optimal braking performance without requiring external intervention or excessive usage, thereby extending component service life while preserving friction coefficient integrity.
4Reliability
If regenerative braking is reduced to increase hydraulic braking, then brake cleaning is improved, but fuel consumption increases
Solution Approach 1:
The system implements periodic friction brake activation that provides effective cleaning without requiring a reduction in overall regenerative braking usage. By concentrating cleaning actions into scheduled periodic events rather than continuously reducing regenerative braking, the system achieves adequate brake maintenance while preserving fuel efficiency during normal operation.
Solution Approach 2:
The system changes the temporal parameters of friction brake usage rather than the magnitude. Instead of reducing regenerative braking to increase friction braking frequency, the system maintains regenerative braking as the primary mode and introduces periodic friction braking events with specific timing and duration parameters optimized for cleaning effectiveness while minimizing energy consumption.
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 method enables efficient energy recuperation through regenerative braking while effectively cleaning wheel brakes to maintain optimal friction coefficients, thus reducing brake wear and fuel consumption. It also ensures a consistent brake pedal feel, enhancing driving comfort and stability.
Implementation Method 1
The regenerative braking device is designed to convert the kinetic energy of the motor vehicle into electrical energy
Implementation Method 2
The friction braking device is designed to convert the kinetic energy of the motor vehicle into thermal energy via friction
Data Source
Figure 1
AI summary
The invention relates to a method for operating a braking system of a motor vehicle, comprising a friction brake device and a recuperation brake device, in which the cleaning requirement of the respective wheel brakes of the friction brake device of the motor vehicle is determined (V1), a deceleration of the motor vehicle desired by the driver is determined based on the position of a brake pedal mechanically decoupled from the friction brake device, and a braking force required for the desired deceleration of the motor vehicle is determined (V2), wherein a first, predetermined part of this braking force is distributed to the recuperation brake device and the remainder of the required braking force is distributed to the wheel brakes of the friction brake device (V3), wherein the braking force to be provided by the friction brake device is distributed to the wheel brakes depending on the determined cleaning requirement of the respective wheel brakes.