High-Pressure Fuel Pump Outlet Valve Noise Reduction
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Solution Overview
Problem
High-pressure fuel pumps face challenges in reducing noise during outlet valve opening and minimizing backflow losses, which affect the delivery level and efficiency, often requiring costly ceramic valve balls and complex designs.
Innovation Solution
A high-pressure fuel pump design featuring a valve spring guided by a recessed stop body with a radially inner limiting surface, allowing for precise guidance and a defined opening stroke, reducing hydraulic adhesion and noise, and utilizing a steel valve ball to replace ceramic materials, along with a pressure-loaded coil spring and strategically placed flow channels for improved functionality and simplified production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional outlet valve design is used, then the valve can open and close based on fuel pressure, but the valve element experiences high hydraulic adhesion to the sealing seat causing noise during opening
Solution Approach 1:
The sealing seat is segmented into a linear portion and a conical portion. The linear portion reduces hydraulic adhesion and noise during opening, while the conical portion maintains sealing effectiveness. This segmentation allows the valve to open quietly while still sealing properly when closed.
2Productivity
If the valve opening stroke is not limited, then the valve can open fully based on pressure differential, but the closing time becomes variable and backflow losses increase
Solution Approach 1:
The stop body with stop portion is positioned to limit the opening stroke of the valve element before full pressure differential opening would occur. This preliminary limitation ensures the valve closes quickly and consistently during the suction phase, preventing backflow losses while still allowing sufficient opening for fuel delivery during the delivery phase.
3Reliability
If a ceramic valve ball is used, then the valve element can withstand high pressure and wear, but the production cost increases significantly
Solution Approach 1:
The valve element is made from a cost-effective material such as steel or plastic instead of expensive ceramic material. While the material is less durable than ceramic, the valve element is designed to be replaceable and relatively inexpensive, making it economically viable for high-volume applications where extreme durability is not critical.
4Device complexity
If the valve spring is not guided precisely, then the assembly is simpler, but the outlet valve construction size increases and functionality deteriorates
Solution Approach 1:
The valve spring is nested within a recess in the stop body, with the radially inner limiting surface of the recess forming a guide for the spring. This nesting arrangement provides precise guidance for the valve spring, reduces the overall construction space of the outlet valve, and maintains simplicity of assembly.
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 design reduces noise, maintains a short and constant closing time for the outlet valve, decreases backflow losses, increases delivery level, and lowers production costs by using economic steel materials and simplifying assembly, while maintaining efficient fuel delivery.
Implementation Method 1
a valve spring (40) acting on the valve ball (38) in the closing direction
Implementation Method 2
the radially inner limiting surface of which forms a guide for the valve spring (40)
Implementation Method 3
an edge of the recess facing the valve ball in the stop body forms an annular stop portion
Implementation Method 4
When however the fuel pressure in the delivery chamber exceeds a counter-force caused by the pressure in the fuel accumulator plus a closing spring force, the outlet valve can open
Data Source
AI summary
A high-pressure fuel pump includes an outlet valve, a valve ball, a valve spring that acts on the valve ball in a closing direction, and a stop body for the valve ball. The stop body has a stop section that limits the opening stroke of the valve ball, and the valve spring is supported by the stop body. The stop body has a cut-out section that at least partially accommodates the valve spring and that has a radial inner periphery which forms a guide for the valve spring.