Pilot Valve Modulation for Precise Brake Pressure Control
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Solution Overview
Problem
Existing pneumatic brake systems for vehicles are complex and require significant effort to control wheel brakes reliably, often relying on fully electronic control systems that can fail or be inefficient in setting precise brake pressures.
Innovation Solution
A method and system utilizing a 3/2-way pilot valve controlled electrically to set an average pilot pressure between minimum and maximum values through alternating ventilation and venting phases, which is then used to modulate brake pressure through check valves, reducing switching times and enabling precise control with fewer hardware components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fully electronic control systems (EBS) are used to control wheel brakes, then precise brake pressure control is achieved, but system complexity increases significantly
Solution Approach 1:
The patent introduces a pilot valve as an intermediary component that receives electrical control signals and translates them into pneumatic control actions. This pilot valve modulates a pilot pressure signal that then controls the main braking valves, serving as a mediator between the electrical control system and the pneumatic braking system, thereby reducing the complexity of direct electronic control while maintaining precision
Solution Approach 2:
The patent replaces complex fully electronic control mechanisms with a hybrid approach that uses pneumatic-pilot-controlled valves. The electrical signals only need to control the small pilot valve, while the actual brake pressure control is achieved through pneumatic amplification via the pilot pressure system, substituting complex electronic pressure regulation with simpler pneumatic mechanics
2Extent of automation
If complex electronic control systems are implemented, then automatic regulatory procedures can be performed, but the system requires more components and higher failure risk
Solution Approach 1:
The pilot valve acts as a reliable intermediary that simplifies the control architecture. By using this single pilot valve to control multiple braking functions through pilot pressure modulation, the system achieves automatic regulatory capabilities without requiring complex electronic control logic for each function, thereby improving reliability
Solution Approach 2:
The pilot valve serves multiple functions: it controls service braking, parking braking, and automatic regulatory procedures through a single component. This multi-functionality reduces the number of separate control systems needed, thereby reducing failure points and improving overall system reliability while maintaining extensive automation
3Measurement precision
If direct electronic control of braking valves is used, then precise brake pressure setting is achieved, but switching times are longer and control effort is higher
Solution Approach 1:
The patent uses periodic modulation of the pilot pressure signal to control brake pressure. The pilot valve switches between positions in a periodic manner, creating a modulated pilot pressure that efficiently controls the braking valves. This periodic action reduces switching times compared to direct continuous control while maintaining precise pressure setting through the modulation frequency and duty cycle
4Device complexity
If simpler pneumatic control systems are used, then system complexity is reduced, but precise brake pressure control becomes difficult
Solution Approach 1:
The pilot valve serves as a precise intermediary that translates simple electrical control signals into precisely modulated pneumatic pilot pressure. This pilot pressure then precisely controls the main braking valves, achieving accurate brake pressure control while keeping the overall system structure simple and avoiding complex electronic pressure regulation
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 allows for reliable and precise control of brake pressure with reduced complexity and effort, enabling automatic braking functions without direct driver input, improving safety and control in various driving conditions.
Implementation Method 1
A method and system utilizing a 3/2-way pilot valve controlled electrically to set an average pilot pressure between minimum and maximum values through alternating ventilation and venting phases
Data Source
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AI summary
The invention relates to a method for controlling a pneumatic brake system (1) of a vehicle (2), comprising at least the following steps: controlling a pilot brake pressure by means of an electropneumatic pilot valve (20) in venting phases (S1_on) and venting phases (t2; S2_off); supplying the pilot pressure via a pilot line (22) to output a brake pressure to wheel brakes (29, 30) of the vehicle (1). It is provided that the pilot valve (20) is controlled from a vented state in alternating venting and venting phases to automatically control a mean pilot pressure level (p_22_mid) such that the pilot pressure (p_22) is increased in the venting phases and decreased in the venting phases (t2).