Vehicle Brake Pressure Sensor Isolation via Solenoid Valves
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Solution Overview
Problem
Existing vehicle-use brake devices employing the by-wire method face challenges in maintaining high accuracy and pressure proof performance, as the sensitivity of liquid pressure sensors is compromised between detecting fine pressure changes and withstanding high pressures, leading to increased power consumption and reduced resolution.
Innovation Solution
A vehicle-use brake device design that includes a master cylinder, brake caliper, solenoid open/close valves, and pressure sensors, where the solenoid valves are controlled to isolate pressure sensors from excessive pressures, allowing high-resolution pressure detection while protecting them from high-pressure conditions, enabling accurate by-wire control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensitivity of the liquid pressure sensor is increased to detect fine pressure changes immediately after starting braking, then the measurement precision is improved, but the pressure proof performance against high pressure is lowered
Solution Approach 1:
The brake system is divided into two separate hydraulic circuits: a first circuit connecting the master cylinder and brake caliper for normal braking operations, and a second circuit connecting the master cylinder and reaction simulator for detecting fine pressure changes. This segmentation allows each circuit to be optimized for its specific function, with the second circuit capable of detecting small pressure changes without being affected by high pressures in the first circuit.
Solution Approach 2:
A solenoid open/close valve is introduced as an intermediary component in the second circuit between the master cylinder and the liquid pressure sensor. This valve acts as a protective barrier that can be closed to isolate the sensor from excessive pressures generated during normal braking operations, while allowing the sensor to detect fine pressure changes when the valve is open during reaction force application.
2Reliability
If electricity is supplied to solenoid open/close valves to maintain them in a standby state, then the reliability is improved, but the power consumption increases
Solution Approach 1:
The solenoid open/close valve transitions from a static standby state to a dynamic control state. The valve is normally closed (non-electricity supply state) during normal braking operations, consuming minimal power. It is dynamically opened (electricity supply state) only when the reaction simulator needs to apply reaction force and when fine pressure detection is required, optimizing the balance between reliability and power consumption.
Solution Approach 2:
The solenoid open/close valve operates periodically rather than continuously. It switches between closed and open states based on the operational requirements of the reaction simulator and the need for fine pressure detection. This periodic operation significantly reduces power consumption compared to maintaining the valve in a constant standby state.
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 solution enhances the accuracy of brake control by allowing high-resolution pressure detection without compromising pressure proof performance, reducing power consumption, and protecting pressure sensors from excessive pressures, thus improving the overall performance of the brake system.
Implementation Method 1
an input-side pressure sensor and an output-side pressure sensor are respectively disposed
Implementation Method 2
a first solenoid open/close valve, which changes over the communication and the interruption between the master cylinder and the brake caliper
Data Source
AI summary
To provide a vehicle-use brake device capable of performing a by-wire-method control of high accuracy in response to an inner pressure in a passage by using a pressure sensor possessing high resolution while causing no trouble in view of pressure proof performance. A master cylinder and a brake caliper are connected with each other by a main brake passage and a normally-open solenoid open/close valve V1 is provided to the passage. A reaction simulator is connected to the passage closer to the master cylinder side than the open/close valve V1 by way of a branch passage. A hydraulic modulator is connected to the passage closer to the brake caliper side than the open/close valve V1 by way of a supply/discharge passage. A normally-closed solenoid open/close valve V2 is provided to the branch passage, while a normally-closed solenoid open/close valve V3 is provided to the supply/discharge passage.