Oil Pump Discharge Passage Design for Pulsation Suppression
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Solution Overview
Problem
Conventional vane oil pumps experience fluid-flow pulsation issues due to the presence of a flow constriction, which affects fuel economy by increasing flow resistance and pulsation in downstream oil passages, and eliminating this constriction worsens pulsation suppression.
Innovation Solution
The design incorporates a discharge passage that is in direct communication with the pressure chamber, allowing for increased volume without actual space expansion, thereby reducing pulsation by eliminating flow constrictions and utilizing part of the discharge passage as additional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow constriction is provided downstream of the discharge opening to suppress oil pulsation, then pulsation suppression is improved, but flow resistance increases and fuel economy deteriorates
Solution Approach 1:
The invention removes the flow constriction (flow control valve) from the discharge passage, extracting the harmful flow resistance element while preserving pulsation suppression through the pressure chamber's inherent damping capability. This eliminates the energy loss associated with the constriction while maintaining reliability.
Solution Approach 2:
The invention segments the discharge system into a pressure chamber (for pulsation suppression) and a discharge passage (for oil flow), allowing each component to perform its specialized function without compromising the other. The pressure chamber handles pulsation damping while the open discharge passage handles flow with minimal resistance.
2Loss of energy
If the flow control valve is abolished to improve fuel economy, then flow resistance is reduced, but pulsation suppression capability is lost
Solution Approach 1:
The pressure chamber serves as an intermediary element between the pump chamber and discharge passage, providing pulsation suppression without requiring a flow control valve. It mediates the transition from high-pulsation pump output to smooth discharge flow.
Solution Approach 2:
The pressure chamber provides self-service pulsation suppression through its inherent volume and connection to the discharge passage, eliminating the need for external flow control valves. The system uses its own structural features rather than additional components.
3Adaptability or versatility
If the discharge passage is positioned to bridge inside and outside of the outer periphery of the pressure chamber, then layout flexibility is maintained, but space utilization becomes complex
Solution Approach 1:
The discharge passage extends in the axial direction (another dimension) rather than radially, allowing it to bridge the inside and outside of the pressure chamber's outer periphery. This dimensional approach simplifies the spatial arrangement while maintaining layout flexibility.
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 effectively suppresses oil pulsation and improves fuel economy by reducing flow resistance and maintaining layout flexibility without significant changes to the pump's volume or layout.
Implementation Method 1
spaces, which are defined between an external toothed portion formed on the outer periphery of inner rotor 94 and an internal toothed portion formed on the inner periphery of outer rotor 95, are displaced around the rotation axis X of the inner rotor, while periodically increasing and decreasing their volumes during rotation of inner rotor 94
Implementation Method 2
the ring-shaped pressure chamber 97 is provided adjacent to the discharge opening 960 for reducing or dampening the fluid-flow pulsation of the oil discharged through the discharge opening 960 within the pressure chamber 97
Data Source
AI summary
An oil pump is provided with an inner rotor having external teeth, an outer rotor disposed in a loose-fit state within a pump chamber and having internal teeth meshed with the external teeth, a ring-shaped pressure chamber provided adjacent to the pump chamber in a direction of a rotation axis, a discharge opening for connecting the pump chamber and the pressure chamber, and a cylindrical discharge passage having one end connected to the pressure chamber and the other end serving as a connection opening. A portion of the discharge passage is located to open inside of the outer periphery of the pressure chamber when viewed in the rotation axis direction. The one end reaches to a middle of the pressure chamber when viewed in a radial direction of the rotation axis, and the discharge passage and the pressure chamber are in direct communication with each other.