Flow Damper Cap Design for Piston Slide Protection
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Solution Overview
Problem
Existing flow dampers face issues with piston slide deterioration due to strong axial force fastening, leading to decreased sliding clearance and faulty operation, making adjustment and replacement of components difficult, resulting in the need for entire unit disposal when outside the appropriate range.
Innovation Solution
A flow damper design incorporating a cap with a small diameter portion fitted into the piston sliding hole and a large diameter portion between the valve body and rail main body, allowing for adjustable fuel flow control without deforming the piston sliding hole, enabling easy replacement of faulty components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve body is fastened to the rail main body using strong axial force, then the sealing between the valve body and rail main body is improved, but the piston sliding hole is deformed and the piston slide is deteriorated
Solution Approach 1:
The invention divides the stopper into two separate components: a cap portion that fits into the piston sliding hole and a stopper portion that restricts piston movement. This segmentation allows the cap to protect the sliding hole from deformation while the stopper maintains its original function, resolving the contradiction between strong fastening and sliding hole precision.
Solution Approach 2:
The cap acts as an intermediary component between the piston sliding hole and the stopper. It protects the sliding hole from the strong axial force during fastening while still allowing the stopper to function properly. The cap absorbs the mechanical stress that would otherwise deform the sliding hole.
2Manufacturing precision
If the stopper is press-fitted into the valve body to prevent piston sliding hole deformation, then the sliding clearance is maintained, but the fuel flow cannot be adjusted after production
Solution Approach 1:
By separating the stopper into a cap portion and a stopper portion, the invention makes the cap removable from the valve body. This allows the stopper portion to remain press-fitted for maintaining sliding clearance, while the cap can be removed to access and adjust the orifice, enabling post-production fuel flow adjustment.
Solution Approach 2:
The invention transitions the stopper from a static, permanently press-fitted component to a dynamic system where the cap can be removed and reinstalled. This dynamic design allows for adjustment of the orifice diameter to change fuel flow characteristics while maintaining the press-fitted connection for precision.
3Manufacturing precision
If the stopper is press-fitted into the valve body, then the piston sliding hole is protected from deformation, but the entire flow damper must be disposed of if the fuel flow is outside the appropriate range
Solution Approach 1:
The invention segments the stopper into removable cap and fixed stopper portions, allowing selective replacement of only the cap/orifice assembly rather than the entire flow damper. This reduces waste and improves ease of manufacture by enabling component-level replacement.
Solution Approach 2:
Instead of discarding the entire flow damper when fuel flow adjustment is needed, the invention allows recovery and reuse of the valve body, piston, spring, and stopper portion. Only the cap and orifice need to be replaced, significantly reducing material waste and manufacturing cost.
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
Prevents piston slide deterioration, facilitates flow adjustment, and allows for component replacement, reducing the need for entire unit disposal and improving product versatility and cost-effectiveness.
Implementation Method 1
a spring (34), and a stopper (35). The spring urges the piston (33) in an opposite direction from a direction of fuel flowing through the fuel passage
Implementation Method 2
The cap (35) includes a small diameter portion (57) and a large diameter portion (58). The small diameter portion (57) is fitted into an inner circumferential surface of the piston sliding hole (43) with a gap (α) between the small diameter portion (57) and the piston sliding hole (43)
Data Source
AI summary
A flow damper includes a valve body, a piston, a spring, and a cap. The valve body is fastened to the rail main body and has a fuel passage therein. The fuel passage communicates between a fuel hole of the rail main body and the injector. The fuel passage includes a piston sliding hole on its rail main body-side. The piston is slidably held on an inner circumferential surface of the piston sliding hole. The spring urges the piston in an opposite direction from a direction of fuel flowing through the fuel passage. The cap includes a small diameter portion and a large diameter portion. The small diameter portion is fitted into the inner circumferential surface of the piston sliding hole with a gap between the small diameter portion and the piston sliding hole. The large diameter portion is located between the valve body and the rail main body.