Fuel Pump Guide Passage Design for Leakage Reduction
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Solution Overview
Problem
Existing fuel pumps experience efficiency reduction due to fuel leakage from the discharge guide passage into the suction guide passage, caused by the configuration of the end parts, which affects the rotation and pulsation of the gears.
Innovation Solution
The fuel pump design includes a discharge guide passage with an outer peripheral part and an inner peripheral part formed along the inner teeth and outer teeth of the gears at a deviation angle, creating a gap with the suction side end part to prevent leakage and ensure smooth rotation, while the manufacturing method uses a circular cutting tool to form the guide passages without changing tools, reducing burr development and improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the discharge side end part is positioned close to the suction side end part to reduce the chamber gap, then the pump chamber volume is reduced, but fuel leaks from the discharge guide passage into the suction guide passage via the sliding surface, reducing pump efficiency
Solution Approach 1:
The discharge side end part is designed with differentiated local structures: the outer peripheral part is positioned at a first position along the inner teeth of the outer gear, while the inner peripheral part is positioned at a second position along the outer teeth of the inner gear. This local differentiation allows the pump chamber volume to be reduced while preventing fuel leakage through strategically positioned gaps between the discharge and suction side end parts.
2Loss of energy
If the discharge guide passage is formed with outer and inner peripheral parts along the gear teeth, then fuel leakage is prevented and pump efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The outer peripheral part and inner peripheral part of the discharge side end part are formed as integrated structures within the pump housing, rather than separate components. This merging approach maintains the functional benefits of preventing fuel leakage while simplifying manufacturing compared to using separate parts.
3Stability of the object's composition
If the outer peripheral part and inner peripheral part of the discharge side end part are formed along the gear teeth at the deviation angle, then pulsation is restricted and smooth rotation is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The outer peripheral part and inner peripheral part of the discharge side end part are formed with curved surfaces that follow the circular paths of the gear teeth at the deviation angle. This curvature design naturally accommodates the rotational motion of the gears, restricting pulsation and ensuring smooth rotation while being amenable to standard machining processes.
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 design enhances pump efficiency by restricting pulsation and fuel leakage, allowing the gears to rotate smoothly and maintaining high efficiency, while simplifying the manufacturing process by preventing fuel from leaking between the sliding surfaces.
Implementation Method 1
an inner gear that includes a plurality of outer teeth and is eccentric from the outer gear in an eccentric direction to be engaged with the outer gear
Implementation Method 2
the outer peripheral part of the discharge side end part is formed along a corresponding one of the plurality of inner teeth, and an inner peripheral part of the discharge side end part is formed along a corresponding one of the plurality of outer teeth
Data Source
AI summary
A suction side end part of a suction guide passage and a discharge side end part of a discharge guide passage are opposed to each other with a gap therebetween. At a deviation angle at which contraction of a pump chamber starts, an outer peripheral part of the discharge side end part is formed along an inner tooth, and an inner peripheral part of the discharge side end part is formed along an outer tooth. A working tool that rotates and cuts circularly is moved around on a pump housing in a single continuous line to form an outline of the discharge guide passage, thereby forming the discharge guide passage. The working tool is moved around on the pump housing in a single continuous line to form an outline of the suction guide passage, thereby forming the suction guide passage.