High-Pressure Fuel Pump With Parallel Relief Valve for Compact Packaging
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Solution Overview
Problem
Existing high-pressure fuel pumps for gasoline direct injection systems face challenges in managing pressure relief due to increased engine efficiency and reduced pump dimensions, requiring a small spill orifice and lengthy spring, which is no longer acceptable.
Innovation Solution
A pressure relief valve (PRV) is arranged parallel to the pumping bore, featuring a resilient valve member and a seat in an elongated chamber, with a plug member sealingly fitted to define a controlled return flow path, allowing pressure relief when the outlet conduit exceeds a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the PRV is arranged transverse to the pumping bore to reduce pump dimensions, then the pump packaging is improved, but the PRV requires a small spill orifice and lengthy spring which increases device complexity and is no longer acceptable
Solution Approach 1:
The PRV chamber is arranged parallel to the pumping bore axis rather than transverse, utilizing the longitudinal dimension of the pump body. This dimensional reorientation allows the PRV to have a more favorable geometry with adequate spill orifice size and spring length, resolving the conflict between compact packaging and acceptable PRV structure complexity
Solution Approach 2:
The pump body is segmented into distinct functional zones: the pumping bore for fuel pressurization and the separate PRV chamber for pressure relief. This segmentation allows each component to be optimized independently - the PRV chamber can be designed with sufficient length and appropriate spill orifice dimensions without compromising the compactness of the overall pump assembly
2Volume of moving object
If the pump dimensions are reduced to improve engine efficiency, then the pump packaging is improved, but the PRV requires a small spill orifice which reduces pressure relief effectiveness
Solution Approach 1:
By reorienting the PRV chamber parallel to the pumping bore, the spill orifice can be positioned to utilize the full cross-sectional area available in the parallel arrangement, rather than being constrained by the transverse configuration. This enables adequate pressure relief capacity within reduced pump dimensions
Solution Approach 2:
The PRV chamber is nested within the pump body structure, with the spill orifice integrated into the plug member that seals the PRV chamber. This nested arrangement allows the spill orifice to be optimally positioned within the available space, maintaining effective pressure relief functionality while minimizing overall pump dimensions
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 arrangement reduces pump packaging by minimizing external dimensions while effectively managing pressure relief, preventing damage during hot-soak conditions.
Implementation Method 1
Said PRV comprises a resilient valve member and a seat
Implementation Method 2
The PRV comprises a spring biasing a ball on a conical seat
Implementation Method 3
only opens when the pressure in the outlet conduit exceeds a second predetermined threshold
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
A high pressure fuel pump (10) provided with a pumping bore (22) and a pressure relief valve (PRV 34) only opening to enable a return flow from the outlet conduit (18) back to the compression chamber (24) when the pressure in the outlet conduit exceeds a predetermined threshold, said PRV being arranged in an elongated PRV chamber extending parallel and offset to the pumping bore.