Brake Vacuum Pump Clutch Control for Fuel Efficiency
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Solution Overview
Problem
In turbocharger vehicles, maintaining a stable negative pressure in the brake negative pressure reservoir is challenging due to the boost pressure in the intake manifold, leading to engine output loss and decreased fuel efficiency when a vacuum pump is continuously operated.
Innovation Solution
A system that selectively uses the negative pressure from both a vacuum pump and an intake manifold, controlled by a negative pressure source selection apparatus, to supply negative pressure to the brake negative pressure reservoir based on the vehicle's running state, minimizing the need for continuous vacuum pump operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum pump is continuously operated to maintain negative pressure in the brake negative pressure reservoir, then the negative pressure is always maintained, but engine output loss occurs and fuel efficiency deteriorates
Solution Approach 1:
The system dynamically switches between two negative pressure sources (intake manifold and vacuum pump) based on operating conditions. The negative pressure source selection apparatus automatically selects the appropriate source: using intake manifold negative pressure when available (normal driving) and switching to vacuum pump when intake manifold cannot provide sufficient negative pressure (turbocharger operation), thereby optimizing fuel efficiency while maintaining brake system reliability
Solution Approach 2:
The negative pressure source selection apparatus acts as an intermediary that manages the transition between two negative pressure sources. It includes control lines that supply compressed air from the turbocharger compressor to the clutch device, enabling automatic engagement/disengagement of the vacuum pump based on system needs
2Reliability
If a vacuum pump is continuously operated to ensure safe braking, then braking safety is maintained, but engine output is reduced
Solution Approach 1:
The system transitions from a static continuous operation mode to a dynamic conditional operation mode. The clutch device engages or disengages the vacuum pump based on real-time operating conditions monitored by the negative pressure source selection apparatus, ensuring braking safety is maintained only when necessary while preserving engine output during normal operations
Solution Approach 2:
The brake negative pressure reservoir system is designed to accept negative pressure from multiple sources (intake manifold and vacuum pump). This multi-functionality allows the system to maintain braking safety through alternative sources when the vacuum pump is disengaged, eliminating the need for continuous vacuum pump operation
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 reduces engine output loss, improves fuel efficiency, and provides a fail-safe mechanism by utilizing intake manifold pressure when the vacuum pump is not needed, enhancing vehicle drivability and fuel efficiency.
Implementation Method 1
a vacuum pump connected to the camshaft through a clutch device, and configured to generate a pump negative pressure
Implementation Method 2
a turbocharger having a compressor configured to supply a compressed air to the engine
Implementation Method 3
a clutch device, and configured to engage or disengage according to operation of the turbocharger
Data Source
AI summary
A system for forming a negative pressure in a negative pressure reservoir of a brake system includes, an engine having an intake manifold and a camshaft, a vacuum pump connected to the camshaft through a clutch device and generating a pump negative pressure, a turbocharger having a compressor supplying a compressed air to the engine, a pump negative pressure line connecting the vacuum pump and the negative pressure reservoir and supplying the pump negative pressure to the negative pressure reservoir, an intake negative pressure line connecting the negative pressure reservoir and the intake manifold and supplying the intake negative pressure of the intake manifold to the negative pressure reservoir, and a negative pressure source selection apparatus configured to control opening and closing of the pump negative pressure line and the intake negative pressure line based on operation of the turbocharger.