Brake Apparatus Pressure Control Mode Switching
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Solution Overview
Problem
Existing brake control systems face challenges in smoothly bringing the wheel cylinder upstream pressure to a target hydraulic pressure, especially during dynamic fluctuations in brake assist and ABS control, leading to increased control load and difficulty in maintaining stable braking forces.
Innovation Solution
A brake control apparatus that includes pressure-regulating control valves and a control unit which switches between pressure-regulating and pressure-maintaining modes to manage upstream pressure, using differential pressure to control valve opening pressures and function as a differential pressure regulating valve, thereby reducing the need for frequent mode switching and alleviating dynamic fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure-control mode is switched between pressure-regulating mode and pressure-maintaining mode based on deviation from target pressure, then the control precision of upstream pressure is improved, but the device complexity increases due to mode switching logic and control unit requirements
Solution Approach 1:
The control system dynamically switches between pressure-regulating mode and pressure-maintaining mode based on the deviation of upstream pressure from target pressure. When deviation exceeds a threshold, the system transitions to pressure-regulating mode with enhanced control; when within threshold, it operates in pressure-maintaining mode, creating a dynamic adaptive control system that improves precision without permanent complexity
Solution Approach 2:
The control range of upstream pressure is segmented into two zones: a threshold zone (within deviation threshold) handled by pressure-maintaining mode, and an out-of-threshold zone (exceeding deviation threshold) handled by pressure-regulating mode. This segmentation allows different control strategies to be applied to different operational conditions, improving overall control precision
2Speed
If the pressure-regulating control valve is frequently opened and closed to maintain upstream pressure during ABS control, then the response speed to pressure fluctuations is improved, but the loss of energy increases due to frequent valve operations
Solution Approach 1:
The system performs preliminary action by switching to pressure-regulating mode before significant pressure deviation occurs (when deviation first exceeds threshold). This proactive control prevents large pressure fluctuations that would require excessive corrective valve operations, thereby reducing energy loss while maintaining fast response
Solution Approach 2:
The control system employs periodic monitoring of upstream pressure deviation and switches modes periodically based on threshold crossings. This periodic control rhythmizes valve operations, avoiding continuous or excessive opening/closing cycles that would increase energy consumption
3Adaptability or versatility
If the volumetric capacity is dynamically adjusted during ABS control to accommodate maintaining valve operations, then the adaptability to different brake conditions is improved, but the stability of upstream pressure control deteriorates due to wide fluctuations
Solution Approach 1:
The control system continuously monitors upstream pressure and provides feedback to the control unit. Based on this feedback, the system determines whether to switch between pressure-regulating mode and pressure-maintaining mode, creating a closed-loop control system that adapts to volumetric capacity fluctuations while stabilizing upstream pressure through corrective actions
Solution Approach 2:
The control system changes the control parameter (mode of operation) based on the deviation of upstream pressure from target pressure. When deviation exceeds threshold, it switches to pressure-regulating mode with different control characteristics; when within threshold, it uses pressure-maintaining mode, adapting control parameters to match operating conditions
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 configuration allows for smoother control of hydraulic pressure, reducing control load and improving the stability of braking forces, even during dynamic fluctuations, enhancing the system's ability to maintain target pressures during brake assist and ABS control.
Implementation Method 1
The valve opening pressure for opening the pressure-regulating control valve in the pressure-maintaining mode is controlled so that the pressure-regulating control valve is opened due to a differential pressure before the pressure-control mode is switched from the pressure-maintaining mode to the pressure-regulating mode.
Data Source
AI summary
A brake apparatus includes multiple wheel cylinders; multiple maintaining valves; a pressure-regulating control valve; and a control unit that controls the upstream pressure by switching a pressure-control mode between a pressure-regulating mode which is selected when a deviation of the upstream pressure from a target pressure is outside a setting range and in which the upstream pressure is brought to the target pressure using the pressure-regulating control valve and a pressure-maintaining mode that is selected when the deviation is within the setting range. The control unit opens the pressure-regulating control valve before the pressure-control mode is switched from the pressure-maintaining mode to the pressure-regulating mode.