Brake Pressure Control With a Double-Stroke Piston and Fewer Valves
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Solution Overview
Problem
Existing braking systems with multiplex control face challenges such as high component complexity, high demands on the electric motor, and inefficiencies in pressure reduction and build-up control, particularly during dynamic operations like ABS with high-μ conditions.
Innovation Solution
A method that utilizes a compact braking system with a minimal number of valves, employing a double-acting piston and intelligent multiplexing to achieve simultaneous or sequential pressure build-up and reduction, with high control quality and dynamics, and reduces the motor requirements by using simple switching valves and few pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a compact braking system with minimal valves is used, then device complexity is reduced, but control quality and performance may deteriorate
Solution Approach 1:
The patent combines pressure build-up and pressure reduction functions into a single integrated control process. The switching valve serves dual purposes: it controls both pressure increase (by connecting pressure supply to wheel brake) and pressure decrease (by connecting wheel brake to reservoir), eliminating the need for separate inlet and outlet valves per wheel brake. This merging of functions reduces valve count while maintaining control capability through centralized pressure management.
Solution Approach 2:
The switching valve is designed as a universal component that performs multiple functions: it acts as both an inlet valve and an outlet valve depending on its position and control signals. The single switching valve per wheel brake can redirect hydraulic flow in both directions (to and from the wheel brake), making it a multi-functional component that replaces what would traditionally require two separate valves, thereby reducing system complexity while preserving control quality.
2Productivity
If simultaneous pressure build-up and reduction is implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The system dynamically adjusts valve positions and pressure supply based on real-time control requirements. The control unit can switch between different operational modes (sequential or simultaneous pressure control) depending on the situation. The switching valve responds dynamically to control signals, enabling the system to adapt its pressure control strategy on-the-fly, achieving high productivity without requiring permanently complex hardware configurations.
Solution Approach 2:
The system changes operational parameters (valve opening/closing timing, pressure supply level) based on control mode requirements. By varying the timing and sequence of valve actuation, the system can achieve simultaneous or sequential pressure control as needed. This parameter-based flexibility allows the same hardware to perform multiple control functions without increasing physical complexity, simply by changing control parameters.
3Measurement precision
If low flow resistance valves are used, then pressure control precision is improved, but motor requirements increase
Solution Approach 1:
The system performs preliminary pressure build-up in the central pressure supply unit before rapid distribution to individual wheel brakes. The motor first pressurizes the central reservoir, then uses the stored pressure energy to quickly actuate the switching valves and fill the wheel brake chambers. This preliminary action allows the use of low flow resistance valves for precise control without requiring the motor to continuously provide high torque during the actual braking pressure application.
Solution Approach 2:
The system uses periodic control cycles where the motor operates in alternating phases: a higher-power phase to build pressure in the central supply, followed by a lower-power phase where pre-compressed gas or stored hydraulic energy maintains pressure while the switching valve rapidly distributes it to wheel brakes. This periodic operation reduces average motor power requirements while maintaining precise pressure control capability when needed.
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 achieves high control quality and performance with reduced cycle times, lower motor requirements, and minimal valve effort, effectively addressing the complexities and inefficiencies of existing systems.
Implementation Method 1
A pressure sensor is used for control, which measures the pressure in the hydraulic connection between the piston-cylinder unit and the wheel brakes
Implementation Method 2
This is achieved via a switching valve and the position-controlled control of a driven piston for pressure build-up and pressure reduction
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
The invention relates to a method for controlled pressure reduction via at least one pressure supply unit of a brake system, wherein a brake pressure of the brake system is reduced using a pressure supply unit (DE) with a double-stroke piston (3) which divides a working chamber into a first working chamber (4) and a second working chamber (4a), wherein a controlled pressure reduction takes place in at least one wheel brake (RB1, RB2, RB3, RB4) via a pressure volume control, a) wherein the following steps are carried out for pressure reduction: - Establishing a fluid connection between the at least one wheel brake (RB1, RB2, RB3, RB4) via an open switching valve (SV1, SV2) which is assigned to the respective at least one wheel brake (RB1, RB2, RB3, RB4), and the first working chamber (4);- Return stroke of the double-stroke piston (3) to increase the volume of the first working chamber (4) and/or b) wherein the following steps are carried out to reduce pressure: - Establishing a fluid connection between the at least one wheel brake (RB1, RB2, RB3, RB4) via the open switching valve (SV1, SV2) assigned to the respective at least one wheel brake (RB1, RB2, RB3, RB4) and the second working chamber (4a); - Opening a first switchable valve (PD3) to establish a fluid connection between reservoir and first working chamber (4); - Forward stroke of the double-stroke piston (3) to increase the volume of the second working chamber (4a).;