Ventilation Valve for Brake Booster Vacuum Maintenance
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Solution Overview
Problem
In vehicles with brake boosters, the vacuum slowly decreases when stationary and the engine is off due to leakage, causing the brake pedal to become unresponsive and preventing vehicle startup, especially in automatic transmissions, as the check valve lacks a return spring which limits pumping efficiency.
Innovation Solution
An apparatus with a ventilation valve having a control input connected to the suction port of a vacuum source and an output between the suction valve and check valve, allowing the line segment between the suction valve and check valve to be vented, ensuring the check valve assumes a closed position and maintains vacuum in the brake booster, even with leakage or long stoppages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closure spring is added to the check valve to maintain vacuum, then vacuum reliability is improved, but pumping efficiency is significantly limited
Solution Approach 1:
The check valve uses the pressure difference between the vacuum side and atmospheric side to automatically close and maintain vacuum, without requiring an external closure spring. The valve closes itself when pressure equalizes, providing reliable vacuum maintenance while avoiding the efficiency penalty of a spring-loaded design.
2Productivity
If the check valve is designed without a closure spring to maintain pumping efficiency, then pumping efficiency is improved, but vacuum reliability deteriorates due to slow venting
Solution Approach 1:
A ventilation valve is introduced as an intermediary component with a control input connected to the suction port. This valve actively manages the line segment between the suction valve and check valve, venting it when needed to ensure the check valve closes properly, thereby maintaining vacuum reliability without compromising pumping efficiency.
Solution Approach 2:
The ventilation valve receives feedback from the suction port pressure and automatically activates to vent the line segment when vacuum is lost or pressure equalizes. This feedback mechanism ensures the check valve assumes its closed position and maintains vacuum in the brake booster, preventing slow venting while preserving pumping efficiency.
3Reliability
If the line segment between suction valve and check valve is vented, then check valve closes reliably, but system complexity increases
Solution Approach 1:
The ventilation valve serves multiple functions: it vents the line segment between the suction valve and check valve, controls pressure in the brake booster, and ensures reliable check valve closure. By combining these functions into a single component with a control input connected to the suction port, the system achieves high reliability without proportionally increasing complexity.
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 ensures the brake pedal can reach the required release point for starting the vehicle, maintaining vacuum in the brake booster by using a pressure-driven tappet and valve element to manage airflow and pressure differences, ensuring reliable vacuum supply to the brake booster.
Implementation Method 1
the first pressure chamber includes a wall constructed in sections formed by an elastic membrane. This elastic membrane is deformed responsive to the pressure in the first pressure chamber and operates as a drive for a tappet
Implementation Method 2
Depending on the pressure in the first pressure chamber, the tappet assumes a position corresponding to the pressure, starting from a threshold value. Opening or closing this valve therefore depends on the pressure in the first pressure chamber.
Data Source
AI summary
The invention relates to a device for producing and providing a vacuum for a vacuum consumer, having a vacuum source, having a suction valve, having a non-return valve arranged between the vacuum consumer and the suction valve, and having a ventilation valve, the control inlet of which ventilation valve is connected to the suction port of the vacuum source, the output of which ventilation valve opens out between the control valve and the non-return valve, and the input of which ventilation valve is open to the environment.