Multi-Stage Valve Control for Vehicle Automatic Braking
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Solution Overview
Problem
Existing automatic braking systems in vehicles experience pressure equalization issues that result in a popping noise and unusual brake pedal movement due to sudden changes in the high-pressure switching valve, leading to discomfort for the driver.
Innovation Solution
A ramp-like increase in control current for a multi-stage high-pressure switching valve is implemented to first open a preliminary stage and then a main stage, minimizing pressure equalization and reducing the discomfort experienced by the driver during automatic braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the high-pressure switching valve switches abruptly from closed to open state during automatic braking, then the braking function is activated quickly, but a pressure compensation impact occurs causing popping noise and brake pedal movement
Solution Approach 1:
The high-pressure switching valve is divided into two stages: a preliminary stage and a main stage. The preliminary stage opens first to gradually equalize pressure, followed by the main stage opening to complete the pressure compensation. This segmentation eliminates the abrupt pressure change that causes popping noise and brake pedal movement while maintaining quick response speed.
2Productivity
If the control current for the high-pressure switching valve is increased abruptly, then the valve opens quickly for fast braking response, but the pressure equalization process causes discomfort to the driver
Solution Approach 1:
The preliminary stage of the valve opens first as a preparatory action before the main stage opens. This preliminary action gradually equalizes the pressure difference across the valve, preventing the sudden pressure compensation impact that causes discomfort. The two-stage approach maintains fast overall response while ensuring comfort during the transition.
3Ease of operation
If a multi-stage valve with ramp-like control current is used, then pressure equalization is minimized improving comfort, but the device complexity increases
Solution Approach 1:
The control current for the multi-stage valve is varied dynamically in a ramp-like manner rather than being constant. The current increases gradually from a first value to a second value during the valve opening process, optimizing the pressure equalization. This dynamic control approach improves comfort while keeping the valve structure itself relatively simple.
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 minimizes pressure equalization, reducing the popping noise and brake pedal movement, thereby enhancing braking comfort and safety by allowing for smoother pressure transitions.
Implementation Method 1
a pressure compensation impact takes place, which the driver notices as a popping noise
Data Source
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AI summary
The invention relates to a method for automatically braking a vehicle by means of a hydraulic brake system (17) which has a multi-stage valve (7) arranged between a master brake cylinder (4) and the suction side of a hydraulic pump (9a, 9b). To lessen a pressure equalization process between a fluid volume at the master brake cylinder side and a suction line (6a, 6b) of the hydraulic pump (9a, 9b), it is proposed that the control current (I) for the valve (7a, 7b) be increased in a ramped manner in order to open firstly a pilot stage and subsequently a main stage of the valve (7a, 7b).