Brake System Pressure Control via Valve Timing and Piston Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ABS/ESP systems face challenges in simultaneously managing pressure reduction and generation across multiple wheel brakes with varying pressure levels, leading to potential pressure equalization and time delays, which affect braking stability and noise levels.
Innovation Solution
The system employs a braking system design with carefully controlled flow resistances and piston speeds, utilizing a pressure model to adjust piston strokes and valve operations, ensuring no pressure equalization occurs during simultaneous or partially simultaneous pressure changes across wheel brakes, allowing for precise pressure management across different pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If simultaneous pressure reduction is implemented in multiple wheel brakes, then braking response time is improved, but pressure equalization between wheel cylinders occurs when pressure levels are unequal
Solution Approach 1:
The system performs preliminary actions by pre-positioning the piston in the pressure-cylinder system and pre-adjusting pressures in wheel brakes before simultaneous pressure reduction is required. This allows the system to be ready for immediate simultaneous pressure reduction across multiple wheels without causing pressure equalization, as the piston and pressures are already in the correct initial states.
Solution Approach 2:
The system dynamically adapts the pressure control strategy based on real-time pressure levels in different wheel brakes. When pressure levels are unequal, the system selectively activates pressure reduction for specific wheels rather than forcing simultaneous reduction across all wheels, thereby maintaining pressure control accuracy while still achieving rapid response when conditions permit.
2Measurement precision
If flow resistance in hydraulic lines is reduced to enable simultaneous pressure control, then pressure control precision is improved, but pressure equalization occurs between wheel cylinders during pressure reduction
Solution Approach 1:
The system changes the flow resistance parameters in the hydraulic lines connecting the pressure-cylinder system to individual wheel brakes. By optimizing these flow resistance values, the system achieves precise pressure control while preventing unwanted pressure equalization between wheel cylinders during pressure reduction operations, thus maintaining both precision and independence of pressure levels.
3Object-affected harmful factors
If PWM control is used for pressure generation, then pressure oscillations and noise are reduced, but control complexity increases and precision is limited
Solution Approach 1:
The system employs periodic PWM control actions to manage pressure generation in the wheel brakes. By using pulsed width modulation with optimized duty cycles and frequencies, the system reduces pressure oscillations and noise while maintaining manageable control complexity through standardized control algorithms.
4Device complexity
If 2/2-way magnetic valves are used for pressure control, then system simplicity is maintained, but pressure oscillations with large amplitude occur due to rapid closing
Solution Approach 1:
The system performs preliminary pressure buildup before closing the 2/2-way magnetic valves. By ensuring that pressure generation is complete or near-complete before valve closure, the system minimizes the pressure differential that would otherwise cause large amplitude pressure oscillations when the valves close rapidly, thus reducing noise while maintaining simple valve architecture.
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
This approach enables simultaneous or partially simultaneous pressure reduction and generation across multiple wheel brakes with varying pressure levels, improving braking stability, reducing noise, and enhancing control accuracy by preventing pressure equalization and allowing for precise pressure adjustments.
Implementation Method 1
2/2-way magnetic valves MV1 to MV4 which are opened or closed depending on the case
Implementation Method 2
a piston-cylinder system HZ or THZ with a magnetically actuated 2/2-way magnetic valve MV0
Data Source
AI summary
A braking system may include a brake booster, the piston-cylinder system of which is driven by an electric motor, wherein at least one working chamber of the piston-cylinder system is connected by hydraulic lines to at least two wheel brakes, a wheel brake being allocated a 2/2-way switching valve in each case and the hydraulic connection lines between the wheel brakes and the piston-cylinder system being closable, optionally separately or jointly, by means of the 2/2-way switching valves, so that a pressure can be adjusted in the wheel brakes one after the other in terms of a multiplex method and/or simultaneously. The electric motor and switching valves may be activated by a control device configured to adjust or control the piston movement and piston speed during the pressure generation and pressure reduction as a function of the pressure-volume characteristic of the wheel brakes.