High-Pressure Fuel Pump Valve Relocation
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Solution Overview
Problem
High-pressure fuel pumps for internal combustion engines face issues with pressure pulsations and increased dead volume in the delivery chamber, leading to reduced efficiency and reliability, particularly due to the conventional placement of pressure relief valves.
Innovation Solution
The pressure relief valve is rearranged to be part of the discharge flow path opening into a step space within the drive-side end region of the pump housing, reducing wear-relevant pressure pulsations and dead volume, and is designed as a spring-loaded check valve with a parallel longitudinal axis to the delivery piston, allowing for a more compact and reliable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure relief valve is arranged in the delivery chamber, then it can seal the high-pressure outlet from the delivery chamber, but it causes wear-related pressure pulsations and increases dead volume
Solution Approach 1:
The pressure relief valve is extracted from the delivery chamber and relocated to the discharge flow path. This separation removes the source of wear-related pressure pulsations from the delivery chamber while maintaining the sealing function. The discharge flow path provides an alternative location that achieves the same pressure relief function without the negative effects on delivery rate.
Solution Approach 2:
The discharge flow path acts as an intermediary structure that connects the high-pressure outlet to the delivery chamber. By placing the pressure relief valve in this intermediate flow path rather than directly in the delivery chamber, the system achieves pressure relief while minimizing the impact on delivery rate through the reduced dead volume.
2Stress or pressure
If the pressure relief valve is arranged in the delivery chamber, then it can limit pressure at the high-pressure outlet, but it significantly increases dead volume in the delivery chamber
Solution Approach 1:
The pressure relief valve is extracted from the delivery chamber and positioned in the discharge flow path. This relocation eliminates the need for additional dead volume in the delivery chamber while maintaining the pressure limitation function. The discharge flow path provides the necessary space for the pressure relief valve without compromising the delivery chamber volume.
3Productivity
If the pressure relief valve is arranged in the discharge flow path opening into the drive-side end face, then dead volume is reduced and delivery rate increases, but the valve must be sealed from drive and lubricants
Solution Approach 1:
The pump housing is segmented into distinct functional zones: the drive section containing the drive mechanism and lubricants, and the discharge flow path section containing the pressure relief valve. This segmentation allows the pressure relief valve to be positioned in the discharge flow path for optimal delivery rate while the sealing structures (seal holder and piston seal) clearly define the boundary between the drive section and the discharge section.
4Length of stationary object
If the pressure relief valve is arranged with longitudinal axis parallel to delivery piston, then overall height of pump is reduced, but assembly and manufacturing must be simplified
Solution Approach 1:
The pressure relief valve is oriented with its longitudinal axis parallel to the delivery piston's longitudinal axis, utilizing the axial dimension of the pump housing. This orientation allows the valve to be integrated into the discharge flow path without increasing the overall height of the pump. The axial alignment with the delivery piston enables compact integration while the discharge flow path opening on the drive-side end face provides accessible assembly points.
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 configuration enhances the efficiency, reliability, and service life of the high-pressure fuel pump by minimizing pressure pulsations and dead volume, while allowing for easier assembly and reduced manufacturing costs.
Implementation Method 1
the pressure relief valve is designed as a spring-loaded check valve
Implementation Method 2
The pressure relief valve opens when the pressure differential between the high-pressure outlet and the delivery chamber of the high-pressure fuel pump exceeds a certain limit
Data Source
Figure 1
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AI summary
A high-pressure fuel pump (10) for a fuel injection system of an internal combustion engine, comprising a pump housing (12), which has a drive-side end-face region (44), a high-pressure outlet (24), and a pressure-limiting valve (58), which in the open state discharges fuel from the high-pressure outlet (24). It is proposed that the pressure-limiting valve (58) is arranged in a discharge flow path (52) in the pump housing (12), which path leads into the drive-side end-face region (44) of the pump housing (12).