Fuel Pump Head External Chamber Inlet Valve Design
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Solution Overview
Problem
Existing high-pressure fuel pumps for common rail fuel injection systems face challenges with high local contact pressure and precise tightening requirements for high-pressure seals, and alternative designs compromise rigidity and manufacturing complexity.
Innovation Solution
A pump head design with an integrated inlet valve arrangement and an external chamber defined by a closure member, eliminating the need for a high-pressure seal by positioning the chamber externally, which reduces structural stress and manufacturing complexity while maintaining high flow rates and pressure performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-pressure seal is used between high- and low-pressure regions, then sealing reliability is improved, but local contact pressure and structural stress increase
Solution Approach 1:
The patent extracts the high-pressure seal from the system by positioning the feeding annulus externally to the pump head housing. This eliminates the need for a high-pressure seal between high- and low-pressure regions within the housing, removing the source of high local contact pressure and structural stress while maintaining sealing reliability through the external low-pressure fuel supply arrangement.
2Reliability
If a high-pressure seal is used, then sealing reliability is improved, but tightening precision requirements increase
Solution Approach 1:
By extracting the high-pressure seal requirement from the internal pump head structure and replacing it with an external feeding annulus arrangement, the patent eliminates the need for precise tightening of internal seals. The external low-pressure fuel supply to the feeding annulus provides sealing without demanding high tightening precision.
3Device complexity
If the feeding annulus is positioned externally to the pump head housing, then high-pressure seal requirements are eliminated, but manufacturing complexity may increase
Solution Approach 1:
The patent integrates the feeding annulus into the inlet valve body, which also serves as the valve housing. This multi-functional design allows the inlet valve body to perform both valve containment and low-pressure fuel distribution functions, eliminating the need for separate sealing components and reducing overall manufacturing complexity despite the external positioning of the feeding annulus.
4Device complexity
If a ball valve is used to eliminate high-pressure seal, then seal complexity is reduced, but guided valve performance is lost
Solution Approach 1:
The patent employs a simple poppet valve design with a valve member that opens and closes against a valve seat. While not as complex as a high-pressure seal system, this design provides adequate sealing for low-pressure fuel supply while maintaining guided valve performance for high flow and pressure capabilities, achieving a balance between simplicity and performance.
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 achieves reliable high flow rates and pressures with reduced part count and manufacturing complexity, eliminating potential leakage paths and structural stress, thereby enhancing performance and cost-effectiveness.
Implementation Method 1
The gallery communicates with a source of low-pressure fuel via the external chamber. The valve member is moveable between open and closed positions in response to fuel pressure within a gallery.
Data Source
AI summary
A pump head suitable for use in a fuel pump for a common rail fuel injection system, comprises a pump head housing defining a plunger bore and a pumping chamber. Fuel is pressurized within the pumping chamber by a plunger reciprocating within the plunger bore. The pump head housing includes an inlet valve arrangement for controlling fuel flow into the pumping chamber. The inlet valve arrangement includes a valve member movable between open and closed positions in response to fuel pressure within a gallery. The gallery communicates with an external chamber defined by a closure member externally mounted to the pump head housing. In use, the gallery communicates with a source of low-pressure fuel via the external chamber. The pump head housing has a projection which locates the closure member on the pump head housing.