Hydraulic Brake Fluid Circulation to Prevent Parked Vapor Lock
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Solution Overview
Problem
In hydraulic motor vehicle brake systems, consecutive braking operations, especially during sporty driving or downhill driving, lead to significant brake fluid heating, which can result in vapor bubble formation, impairing brake functionality, even after the vehicle is parked, due to heat transfer from wheel brake components to the brake fluid.
Innovation Solution
The method involves opening control valves in the vehicle dynamics control module after the vehicle is parked to generate hydraulic pressure intervals, conveying brake fluid to the wheel brakes and allowing it to flow back, mixing warm and cool fluid to prevent vapor bubble formation, using a temperature model to determine the necessary intervals and duration based on previous driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return line cooling system is used to cool brake fluid, then vapor lock prevention is improved, but device complexity increases
Solution Approach 1:
The invention extracts the essential cooling function from the complex return line system and implements it through a simplified circulation mechanism using existing brake system components. The brake fluid is circulated through the brake calipers and lines without requiring a separate return line infrastructure, thereby achieving vapor lock prevention while reducing system complexity.
Solution Approach 2:
The invention makes the existing brake hydraulic lines serve dual functions: both brake actuation and heat dissipation. The same lines that deliver brake pressure also serve as cooling channels during fluid circulation, eliminating the need for dedicated cooling return lines and reducing overall system complexity.
2Temperature
If brake fluid is circulated continuously to prevent overheating, then temperature control is improved, but energy consumption increases
Solution Approach 1:
The invention implements periodic circulation of brake fluid rather than continuous circulation. The pump operates in cycles, circulating fluid through the brake system at intervals to dissipate heat, then remains inactive. This periodic action maintains effective temperature control while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The brake system utilizes its own hydraulic pressure and existing components to achieve cooling, minimizing the need for external energy input. The circulation mechanism leverages the brake system's inherent properties and components, requiring minimal pump intervention to achieve effective heat dissipation.
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 effectively prevents vapor bubble formation by gradually exchanging heat within the brake pressure lines, ensuring brake fluid remains at a safe temperature, even after the vehicle is parked, thereby maintaining brake functionality.
Implementation Method 1
a hydraulic pressure is generated at intervals (pressure intervals) and brake fluid is thereby conveyed in the direction of the wheel brakes, the brake fluid flowing back in the interval pauses (ie between the pressure intervals) so that warm and cool or at least cooler brake fluid are mixed in the brake pressure lines
Implementation Method 2
the brake fluid flowing back in the interval pauses so that warm and cool or at least cooler brake fluid are mixed in the brake pressure lines and the formation of vapor bubbles is thereby (preventively) avoided
Data Source
Figure 1~2
AI summary
The invention relates to a method for preventative vapour bubble avoidance in a hydraulic motor vehicle braking system (100) of a motor vehicle, comprising - front wheel brakes (110) and rear wheel brakes (120); - a main brake cylinder (140); - a driving dynamics control module (160) having control valves (161); and - hydraulic brake pressure lines (170), by means of which the wheel brakes (110, 120) are connected to the driving dynamics control module (160). According to the method, once the motor vehicle has been switched off with the vehicle at a standstill, the control valves (161) of the driving dynamics control module (160) are opened and a hydraulic pressure is generated in intervals and brake fluid is thus conveyed in the direction of the wheel brakes (110, 120) and flows back in the pauses between the intervals, so that hot and cold brake fluid are mixed in the brake pressure lines (170) and the formation of vapour bubbles is thus avoided. The invention also relates to a corresponding motor vehicle braking system (100), and also to a motor vehicle comprising such a motor vehicle braking system (100).