Brake Control Device Using Differential Pressure Feedback
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Solution Overview
Problem
Conventional brake control devices struggle to accurately regulate wheel cylinder pressure without sensors for detecting brake fluid pressure, leading to inaccuracies in pressure increase or reduction.
Innovation Solution
A brake control device that incorporates a flow control valve, differential pressure obtaining means, hydrodynamic force obtaining means, and brake fluid pressure control means to regulate brake fluid pressure by controlling the flow rate and using information on differential pressure and hydrodynamic forces to determine the applied current for precise control of the flow control valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are installed to detect brake fluid pressure for feedback control, then pressure control accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The flow control valve itself generates the necessary measurement information by producing a differential pressure that is proportional to the flow rate. This differential pressure serves as a self-measuring mechanism, eliminating the need for external pressure sensors while providing accurate flow and pressure control information for the feedback control system.
Solution Approach 2:
A differential pressure generating structure is introduced as an intermediary element between the upstream and downstream brake fluid pressure zones. This structure creates a measurable differential pressure that reflects the actual flow conditions, serving as a mediator that provides measurement information without requiring direct pressure sensing in the main fluid path.
2Speed
If applied current to the flow control valve is increased to quickly increase wheel cylinder pressure, then pressure increase speed is improved, but valve opening degree increases causing operation sound and vibration
Solution Approach 1:
The system uses feedback control where the differential pressure obtained from the flow control valve is continuously monitored and used to adjust the applied current. This feedback mechanism allows the system to achieve rapid pressure increase when needed while automatically reducing valve opening degree and current when the target pressure is approached, thereby minimizing operation sound and vibration.
Solution Approach 2:
The flow control valve operates dynamically with continuously adjustable opening degree based on real-time differential pressure feedback. The valve transitions from large opening for rapid pressure increase to small opening for precise pressure maintenance, optimizing both speed and reducing harmful operations throughout the pressure control process.
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
Enables precise control of wheel cylinder pressure with high accuracy, reducing operation sound and vibration, and quickly increasing pressure while minimizing valve opening degree, thus improving the brake control device's performance without the need for pressure sensors.
Implementation Method 1
a hydrodynamic force obtaining means that obtains information on hydrodynamic force induced in a valve element by a flow of brake fluid passing through the flow control valve
Implementation Method 2
a brake fluid pressure control means that controls the flow control valve by use of the information on the differential pressure and the information on the hydrodynamic force
Data Source
AI summary
Included are pressure increasing valves and pressure reducing valves as flow control valves, placed between a brake fluid pressure generation unit on an upstream side that generates brake fluid pressure and a braking force generation unit on a downstream side that generates braking force in accordance with the brake fluid pressure to a wheel, that regulates the brake fluid pressure to the braking force generation unit by controlling the flow rate of brake fluid, and an electronic control unit is provided with: a differential pressure obtaining unit that obtains information on the difference of brake fluid pressure from the brake fluid pressure on upstream and downstream sides of the flow control valve; a hydrodynamic force obtaining unit that obtains information on hydrodynamic force induced in a valve element by the flow of brake fluid passing through the flow control valve; and a brake fluid pressure control unit that controls the flow control valve by use of the information on the differential pressure and the information on the hydrodynamic force.