Brake Pressure Switching Valve for Low-Temperature Boosting
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Solution Overview
Problem
Existing vehicle brake systems experience reduced braking performance at low temperatures due to the reduced fluidity of hydraulic fluid, particularly when the system relies on the master cylinder for pressure generation.
Innovation Solution
The vehicle brake system incorporates a switching valve that can switch between two states to either connect the vehicle behavior stabilizing device with the first fluid pressure generating device or the second fluid pressure generating device, allowing the system to receive hydraulic fluid from the second device even when the first device is unable to generate pressure, thus enhancing pressure boosting performance at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switching valve connects the master cylinder to the vehicle behavior stabilizing device when abnormality occurs, then the brake system can maintain basic braking function, but the braking performance is significantly reduced at low temperatures due to poor hydraulic fluid fluidity
Solution Approach 1:
The switching valve is configured to dynamically switch between different connection states based on operational conditions. During automatic brake control, it connects the slave cylinder to the vehicle behavior stabilizing device, while during abnormality it can connect the master cylinder. This dynamic switching capability allows the system to adapt to different temperature conditions and operational states, optimizing braking performance while maintaining reliability.
Solution Approach 2:
The system changes the connection parameters of the hydraulic circuit through the switching valve. By altering which cylinder (master or slave) is connected to the vehicle behavior stabilizing device, the system optimizes the hydraulic fluid flow characteristics. The slave cylinder connection during automatic brake control provides better fluidity and pressure transmission, improving braking performance at low temperatures.
2Productivity
If the slave cylinder is used for automatic brake control, then the braking performance is improved due to better hydraulic fluid fluidity, but the system complexity increases with additional switching valve states
Solution Approach 1:
The switching valve is designed to perform multiple functions: it switches between normal braking mode (master cylinder connection) and automatic brake control mode (slave cylinder connection), and also handles abnormality scenarios. This multi-functionality allows a single component to manage different operational requirements without proportionally increasing system complexity.
Solution Approach 2:
The switching valve acts as an intermediary component that mediates between the two fluid pressure generating devices (master and slave cylinders) and the vehicle behavior stabilizing device. It intelligently routes hydraulic fluid based on control signals, simplifying the overall system architecture while enabling optimized performance for automatic brake control.
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 enhances the pressure boosting performance of the vehicle behavior stabilizing device at low temperatures, ensuring reliable braking performance while reducing the overall size of the brake system by shortening the oil passages.
Implementation Method 1
a vehicle behavior stabilizing device (26) provided in the oil passage between the switching valve and the frictional brake (7), to adjust a fluid pressure of a hydraulic fluid supplied from either the first fluid pressure generating device (15) or the second fluid pressure generating device (13) and to apply an adjusted fluid pressure to the frictional brake (7)
Implementation Method 2
a switching valve (24a, 24b) configured to switch oil passages (16) so that the frictional brake (7) is functionally connected to one of the first fluid pressure generating device (15) and the second fluid pressure generating device (13)
Data Source
AI summary
A vehicle brake system includes a first fluid pressure generating device for generating a fluid pressure according to a brake operating amount, a second fluid pressure generating device for generating a fluid pressure by moving a piston with an electric actuator, and a switching valve switchable between a first state allowing communication between the first fluid pressure generating device and a vehicle behavior stabilizing device and a second state allowing communication between the second fluid pressure generating device and the vehicle behavior stabilizing device. A control device places the switching valve in the second state during execution of automatic brake control, and places the switching valve in the first state when a predetermined abnormality occurs in the vehicle, except that the control device places the switching valve in the second state when an abnormality including inability of the second fluid pressure generating device to generate the fluid pressure occurs.