Gas Pump Pressure Relief for Reducing Starting Torque
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Solution Overview
Problem
Negative pressure pumps face high drive torques and risks of damage when starting due to viscous engine oil, leading to potential damage to the delivery device and increased fuel consumption and CO2 emissions, especially when arranged in the oil sump of a vehicle engine.
Innovation Solution
A gas pump design featuring a sealing join between two housing parts that widens to form a relieving gap, allowing excess oil to escape, reducing forces on the delivery device, with a pressing device generating a spring force to maintain the seal and control the gap width, thus minimizing power losses and avoiding the need for additional design features like reverse rotary valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative pressure pump is arranged in the oil sump and starts up, then the pump can deliver negative pressure for brake servo, but high drive torques occur due to viscous engine oil causing potential damage to the delivery device
Solution Approach 1:
The patent applies preliminary action by providing a relief opening in the delivery chamber before the pump starts up. This relief opening allows viscous engine oil to escape from the delivery chamber prior to the pump rotor rotating, preventing the oil from creating high drive torques that could damage the delivery device during startup. The relief opening is closed during normal operation but open during startup to relieve excess pressure and fluid.
Solution Approach 2:
The patent extracts the harmful factor (viscous engine oil) from the delivery chamber by providing a relief opening that allows the oil to escape before the pump starts rotating. This removes the source of high drive torques and potential damage to the delivery device, separating the harmful fluid from the pump mechanism at the critical startup moment.
2Reliability
If reverse rotary valves are fitted to avoid damage, then the delivery device is protected, but additional design outlay and cost are associated
Solution Approach 1:
The patent extracts the harmful factor (viscous engine oil) from the delivery chamber by providing a relief opening that allows the oil to escape before the pump starts rotating. This removes the source of high drive torques and potential damage to the delivery device, separating the harmful fluid from the pump mechanism at the critical startup moment.
Solution Approach 2:
The relief opening acts as a simple, inexpensive protective feature compared to complex reverse rotary valves. It is a basic structural feature that can be implemented as a simple opening or passage in the delivery chamber, requiring no moving parts or complex mechanisms, thus reducing design outlay and cost while providing adequate protection during startup.
3Reliability
If reverse rotary valves or oil retention valves are added, then damage is prevented, but the evacuating rate and effectiveness of the pump are reduced
Solution Approach 1:
The relief opening is designed to be dynamically open during startup when needed to relieve excess viscous oil, and then closed during normal pump operation to maintain sealing and evacuation effectiveness. This dynamic behavior ensures the pump achieves full evacuating rate during normal operation while still providing protection during startup through the temporary opening of the relief passage.
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 effectively reduces the forces and torques on the delivery device during startup, preventing damage and reducing fuel consumption and emissions by allowing excess oil to escape without impairing the pump's delivery rate, thus enhancing the pump's reliability and cost-effectiveness.
Implementation Method 1
the pressing device is configured such that the pressing force of the pressing device is reached when a maximum pressure which prevails in the delivery chamber and acts on the second housing part is reached
Data Source
AI summary
A gas pump including a delivery chamber with an inlet and an outlet for a gas. The delivery chamber is at least partially enclosed by a first housing part with a first sealing surface and a second housing part with a second sealing surface. A delivery device is moveable within the delivery chamber for delivering the gas. A pressing device presses one of the housing parts against the other with a pressing force such that the sealing surfaces abut each other and together form a sealing join which at least partially surrounds the delivery chamber in order to seal off the delivery chamber. The second housing part can be moved relative to the first housing part, against the pressing force, in order to be able to widen the sealing join to form a relieving gap through which liquid situated in the delivery chamber can escape.