High-Pressure Fuel Pump Relief Passage Layout for Valve Life
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Solution Overview
Problem
Conventional high-pressure fuel pumps for GDI engines face challenges in rapidly relieving abnormal high-pressure states, leading to reduced compression and discharge efficiency, and premature failure of pressure relief valves due to high-pressure fuel flowback.
Innovation Solution
The high-pressure fuel pump design connects the relief flow passage directly with a low-pressure flow passage instead of a chamber, allowing for rapid relief of abnormal pressures without returning fuel to the high-pressure chamber, enhancing efficiency and extending valve lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure relief valve is connected to the high-pressure chamber to relieve abnormal pressure, then the pressure relief function is provided, but the compression efficiency and discharge efficiency are reduced due to the large chamber volume required to receive returned fuel
Solution Approach 1:
The invention segments the pressure relief pathway from the high-pressure chamber by introducing an intermediate low-pressure flow passage. The relief flow passage is connected to the low-pressure flow passage rather than directly to the high-pressure chamber, creating a separate relief pathway that does not interfere with the compression chamber volume or efficiency.
Solution Approach 2:
The low-pressure flow passage serves as an intermediary between the discharge flow passage and the fuel tank. Returned fuel from the pressure relief valve first enters the low-pressure flow passage, which acts as a buffer zone, preventing direct communication between the high-pressure chamber and the relief pathway while still enabling pressure relief functionality.
2Reliability
If the relief flow passage communicates with the high-pressure chamber to enable pressure relief, then abnormal high pressure can be relieved, but high-pressure fuel flows backward into the relief passage causing valve malfunction and reduced lifetime
Solution Approach 1:
The invention divides the fuel flow system into distinct pressure zones. The relief flow passage is segmented from the high-pressure chamber and connected only to the low-pressure flow passage, creating a physical barrier that prevents high-pressure fuel from entering the relief passage and damaging the pressure relief valve.
Solution Approach 2:
The low-pressure flow passage acts as an intermediary that receives fuel from both the main supply and the pressure relief valve. This intermediary pathway ensures that fuel returning through the pressure relief valve does not directly contact high-pressure fuel, thereby protecting the valve from high-pressure erosion and extending its service life.
3Reliability
If a large chamber volume is used to receive returned fuel for pressure relief, then the pressure relief function is achieved, but the compression efficiency and discharge efficiency are reduced
Solution Approach 1:
The invention segments the fuel return pathway from the compression chamber by routing it through a separate low-pressure flow passage. This allows the chamber to maintain its optimal compression volume without needing to accommodate large amounts of returned fuel, thereby preserving compression efficiency while still providing pressure relief capability.
Solution Approach 2:
The invention resolves the volume conflict by transitioning from a single-chamber design to a multi-passage three-dimensional layout. The relief flow passage is positioned in a different spatial dimension relative to the compression chamber, allowing pressure relief functionality without compromising the chamber's compression volume or efficiency.
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 effectively reduces abnormal high-pressure states, improves compression and discharge efficiency, and prolongs the life of pressure relief valves by preventing high-pressure fuel flowback into the relief passage.
Implementation Method 1
a spring (430) having a first end supported by the open-and-close member (420), and a second end supported in the damper aperture (224)
Implementation Method 2
a piston (241) disposed in the housing (200) and configured to linearly reciprocate to compress fuel supplied into the chamber (221)
Implementation Method 3
a discharge valve (300) disposed in the discharge flow passage (223) of the housing (200) and configured to open when a pressure of fuel stored in the chamber (221) is equal to or greater than a first pressure
Implementation Method 4
a pressure relief valve (400) disposed in a relief flow passage (225) which is formed in the housing (200) and communicates with the discharge flow passage (223) and the space (227), and configured to open when a pressure of fuel supplied into the relief flow passage (225) is equal to or greater than a second pressure
Implementation Method 5
a damper (230) disposed in an upper portion of the housing (200), and configured to reduce pulsation of fuel drawn thereinto through an inlet port (251)
Data Source
AI summary
A high-pressure fuel pump includes a housing including a chamber, an inlet flow passage to draw fuel into the chamber, and a discharge flow passage to discharge fuel out of the chamber. The high-pressure fuel pump further includes a piston disposed in the housing and configured to compress fuel, a sleeve coupled to the housing and configured to support the piston and form a space for storing fuel, a discharge valve disposed in the discharge flow passage and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, and a pressure relief valve disposed in a relief flow passage that communicates with the discharge flow passage and the space. The pressure relief valve is configured to open when a pressure of fuel supplied into the relief flow passage is equal to or greater than a second pressure.