High-Pressure Fuel Pump Sealing Ring Thermal Management
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Solution Overview
Problem
High-pressure fuel pumps in internal combustion engines face thermal loading issues due to the lack of continuous flow through the sealing ring area, leading to increased wear and potential fuel mixing with lubricating oil.
Innovation Solution
A bypass connection is introduced to ensure constant fuel flow through the space surrounding the sealing ring, even when the inlet valve is closed, utilizing a pressure valve or throttle to manage flow, thereby reducing thermal load on the sealing ring and preventing fuel and lubricating oil leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel flow is only provided when the inlet valve is open, then the pump structure is simple, but the sealing ring experiences thermal loading and wear increases
Solution Approach 1:
The fuel supply system is segmented into two separate inlet sections: a first inlet section that provides fuel flow during pump operation, and a second inlet section that provides continuous fuel flow through the bypass connection to the relief area. This segmentation allows the cooling function to be independent from the pumping function, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The bypass connection acts as an intermediary pathway that introduces continuous fuel flow to the relief area around the sealing ring, independent of the main pumping cycle. This intermediary system ensures thermal management without requiring complex control mechanisms, balancing simplicity and reliability.
2Temperature
If there is no continuous fuel flow through the sealing ring area, then the system is simpler to operate, but thermal stress on the sealing ring increases
Solution Approach 1:
The bypass connection ensures continuous fuel flow through the relief area around the sealing ring, regardless of the inlet valve position. This continuous flow provides constant cooling to the sealing ring, maintaining low temperature without requiring active control or complex operation, thus resolving the contradiction between temperature control and ease of operation.
3Reliability
If the bypass connection is added to ensure constant fuel flow, then thermal loading on the sealing ring is reduced, but the device complexity increases
Solution Approach 1:
The fuel supply line is divided into two independent inlet sections: the first inlet section connected to the pump inlet for main fuel delivery, and the second inlet section connected to the bypass connection for continuous cooling flow. This segmentation allows the cooling function to operate independently with minimal additional complexity, improving reliability while maintaining operational simplicity.
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 solution effectively reduces thermal loading on the sealing ring by maintaining fuel flow through the bypass connection, ensuring efficient cooling and minimizing leakage between fuel and lubricating oil circuits, thus enhancing the pump's operational reliability and longevity.
Implementation Method 1
the space through the bypass connection is constantly flowed with fuel, which flows into the relief area, regardless of the fuel delivery of the pump element
Implementation Method 2
The sealing ring serves to prevent the fuel pumped by the pump piston from mixing with the medium present outside the cylinder bore of the housing part
Data Source
Figure 1
Figure 2
AI summary
The pump has at least one pump element (10) that includes a pump piston (12) which is driven in a reciprocating motion, is guided so as to be displaceable in a cylinder bore (18) of a housing part (20) of the pump, and delimits a pump working chamber (22) in said cylinder bore. The end of the pump piston (12) facing away from the pump working chamber (22) protrudes from the cylinder bore (18). The housing part (20) has an at least approximately cylindrical section (50) which surrounds the end portion of the cylinder bore (18) facing away from the pump working chamber (22). A sealing ring (52), the inner circumference of which rests against the pump piston (12) by way of a sealing lip (54), is arranged on the end portion of the pump piston (12) protruding from the cylinder bore (18). The sealing ring (52) is placed in a receptacle (58, 60) of the pump housing part (20), said receptacle surrounding the end portion of the pump piston (12) protruding from the cylinder bore (18); the sealing ring (52) and the pump housing part (20) delimit a chamber (74; 76) in the direction of the cylinder bore (18), said chamber being connected to a fuel supply line (26). The fuel supply line (26) runs through the chamber (74; 76) such that fuel that leaks into the chamber (74; 76) is discharged from the chamber (74; 76) by the stream in the fuel supply line (26).