High-Pressure Fuel Pump Valve Layout for Precise Opening Pressure
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Solution Overview
Problem
The existing high-pressure fuel pumps require a separate part to be pressed into the pressure-limiting valve bore during assembly, complicating the manufacturing process and making it difficult to precisely set the opening pressure of the pressure-limiting valve.
Innovation Solution
The pressure-limiting valve is integrated into a through bore in the pump body, extending from the damping region to the stepped chamber, with a spiral spring supported on an annular step, allowing for easy assembly and precise setting of the opening pressure without additional sealing points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a blind bore is used for the pressure-limiting valve, then the valve can be integrated into the pump body, but a separate part must be pressed in during assembly which complicates the manufacturing process
Solution Approach 1:
The pressure-limiting valve bore is divided into two segments: a first portion with larger diameter and a second portion with smaller diameter. The spiral spring is positioned in the first portion while the valve element operates in the second portion, allowing each component to be optimally positioned without requiring additional separate parts to be pressed in during assembly.
Solution Approach 2:
The pressure-limiting valve bore is designed as a stepped bore with varying diameters along its length, creating a three-dimensional structure that accommodates both the spiral spring and valve element within a single integrated feature of the pump body, eliminating the need for separate assembled parts.
2Reliability
If a separate part is pressed into the pressure-limiting valve bore to support the spiral spring, then the valve can function, but it becomes difficult to precisely set the opening pressure
Solution Approach 1:
The opening pressure of the pressure-limiting valve can be precisely adjusted by varying the diameter of the first portion of the pressure-limiting valve bore. By changing this geometric parameter during manufacturing, the spring preload and consequently the opening pressure can be precisely controlled without requiring separate adjustment parts or complex assembly procedures.
3Device complexity
If additional sealing points are added to accommodate the pressure-limiting valve, then the valve can be integrated, but the device becomes more complex
Solution Approach 1:
The pressure-limiting valve bore serves multiple functions within a single structural feature: it provides the flow path for fuel, supports the spiral spring through its stepped geometry, positions the valve element, and eliminates the need for separate sealing components by integrating all these functions into the pump body's internal geometry.
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 simplifies the assembly process, allows for precise setting of the opening pressure, and optimizes space usage within the pump body, making it more efficient and compact.
Implementation Method 1
the pressure-limiting valve has a valve element which has the shape of a ball and which comes into sealing contact with the valve seat, wherein the valve element is pressed in the closing direction by a holding element, wherein the holding element is pressed in the closing direction by a spiral spring
Implementation Method 2
fuel flows out of the high-pressure region into the low-pressure region when the pressure difference between fuel in the high-pressure region and fuel in the low-pressure region exceeds an opening pressure
Data Source
AI summary
A high-pressure fuel pump has a pressure-limiting valve, which fluidically connects a high-pressure region to a low-pressure region and opens towards the low-pressure region. The pressure-limiting valve is disposed in a pressure-limiting valve bore, which is designed as a through bore through the pump body, extends from a damping region to a stepped chamber, and is closed on the side facing the damping region by a pressed-in closure. The pressure-limiting valve bore is a stepped bore having a larger diameter first portion, a smaller diameter second portion, and an annular step between the first and second portions The pressure-limiting valve has a valve seat body pressed into the pressure-limiting valve bore, and a valve element, which is pushed in the closing direction by a holding element, which is pushed in the closing direction by a spiral spring, which is supported on the annular step.