Fuel Pump Valve Assembly with Tapered Helical Spring
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Solution Overview
Problem
Conventional valve assemblies in fuel pumps for common rail fuel injection systems face limitations in design complexity and tolerance requirements due to the use of multiple parts and non-resilient spring seats, which can lead to inefficiencies in valve operation and pressure management.
Innovation Solution
A valve assembly utilizing a helical spring with varying diameters, where one end forms an interference fit with the valve member, reducing the number of parts and allowing for significant design tolerance, with a preferred configuration of close-wound turns and a closed loop at one end, enhancing resilience and interference fit rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional valve assemblies use multiple parts and non-resilient spring seats, then the structure provides stable mounting, but the design complexity increases and tolerance requirements become more stringent
Solution Approach 1:
The spring seat and spring are merged into a single integrated component. The helical spring forms an interference fit directly with the valve member, eliminating the need for separate spring seats. This reduces the number of parts while maintaining stable mounting through the interference fit mechanism.
Solution Approach 2:
The helical spring serves multiple functions simultaneously: it provides the biasing force for the valve member and acts as its own mounting structure through the interference fit. This multi-functionality eliminates the need for separate spring seats and reduces overall assembly complexity.
2Reliability
If conventional valve assemblies use multiple parts and non-resilient spring seats, then the structure provides stable mounting, but the manufacturing precision requirements increase
Solution Approach 1:
The spring diameter is designed to be larger than the valve member diameter, creating an interference fit. This parameter change allows the resilient spring to accommodate tolerance variations while maintaining stable mounting. The elasticity of the spring compensates for manufacturing tolerances that would be critical in rigid spring seat designs.
3Manufacturing precision
If the spring diameter is made larger than the valve member diameter, then significant design tolerance is allowed, but the spring requires retention mechanism
Solution Approach 1:
The retention mechanism is merged with the spring itself through the interference fit. The spring's own elasticity and dimensional relationship with the valve member provide the retention mechanism, eliminating the need for separate retention components.
Solution Approach 2:
The spring serves itself by using its own elastic properties and dimensional characteristics to create the retention mechanism. The interference fit between the spring and valve member is self-retaining, eliminating the need for external retention structures.
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 simplifies the valve assembly design, reduces tolerance requirements, and improves resilience, enabling efficient operation and pressure management by minimizing stress and maintaining predictable spring performance across varying loads and pressures.
Implementation Method 1
the helical spring at either the first part or the second part is retained by an interference fit against the member with respect to which it is fixed
Implementation Method 2
biasing means having a first part fixed with respect to one of the body member and the valve member and a second part fixed with respect to the other of the body member and the valve member, the biasing means being adapted to bias the valve member to close the valve aperture
Data Source
Figure 1~2
Figure 3
AI summary
A valve assembly for use in a fuel pump comprises a body member (43) with a valve aperture (26,36), a valve member (22,32) movable within the body member and adapted to close the valve aperture (26,36), and a biasing means having a first part fixed with respect to one of the body member (43) and the valve member (22,32) and a second part fixed with respect to the other of the body member and the valve member (22,32). The biasing means is adapted to bias the valve member (22,32) to close the valve aperture (26,36). The biasing means comprises a helical spring (28,38) with a first diameter at the first part and a second diameter at the second part. The first diameter of the helical spring is different from the second diameter of the spring. The helical spring is at its first part retained by an interference fit against the member with respect to which it is fixed.