High Pressure Fuel Pump Release Passage Backflow Control
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Solution Overview
Problem
Existing high pressure fuel pump systems experience excessive energy loss due to backflow in the suction passage during the delivery stroke, which requires high fuel pressure from the low pressure fuel pump to counteract the backflow, leading to inefficient fuel suction into the pressurizing chamber.
Innovation Solution
Incorporating a release passage that relieves pressurized fuel from the pressurizing chamber before the closing timing during the delivery stroke, reducing backflow by directing it into the release passage, which is communicated with the suction passage, thereby minimizing energy loss by maintaining a forward flow state during the suction stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the control valve closes the connection between the suction passage and the pressurizing chamber at the closing timing during the delivery stroke, then the amount of returned fuel can be accurately controlled, but backflow is generated in the suction passage causing excessive energy loss
Solution Approach 1:
The invention divides the fuel return path into two separate paths: a first return passage that allows fuel to return from the pressurizing chamber to the suction passage, and a second return passage that allows fuel to return from the suction passage to the fuel tank. This segmentation prevents backflow in the suction passage while maintaining control over the amount of fuel returned, thereby resolving the contradiction between control precision and energy loss.
2Productivity
If high fuel pressure is applied at the low pressure fuel pump to counteract backflow, then fuel can be suctioned into the pressurizing chamber, but energy consumption increases excessively
Solution Approach 1:
The invention extracts the harmful backflow effect from the suction passage by providing a separate first return passage that allows pressurized fuel to return directly from the pressurizing chamber to the suction passage. This eliminates the need for high fuel pressure at the low pressure fuel pump to counteract backflow, thereby maintaining fuel suction efficiency while reducing energy consumption.
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 limits energy loss by reducing the energy required for fuel suction into the pressurizing chamber, enhancing the fuel supply efficiency and reducing the operational energy needed from the low pressure fuel pump.
Implementation Method 1
the release passage relieves the fuel, which is pressurized by the plunger, from the pressurizing chamber before the closing timing during the delivery stroke
Implementation Method 2
a control valve that opens a connection between the suction passage and the pressurizing chamber in a suction stroke, during which the plunger is driven toward a suction side for suctioning the fuel into the pressurizing chamber, while the control valve controls closing timing, at which the connection between the suction passage and the pressurizing chamber is closed by the control valve in a delivery stroke
Implementation Method 3
the plunger is driven toward a delivery side for delivering the fuel out of the pressurizing chamber upon pressurization of the fuel
Implementation Method 4
the plunger is driven toward a suction side for suctioning the fuel into the pressurizing chamber
Data Source
AI summary
A high pressure fuel pump includes: a pump body that forms a suction passage and a pressurizing chamber and slidably supports a plunger; and a control valve that opens a connection between the suction passage and the pressurizing chamber in a suction stroke, during which the plunger is driven toward a suction side for suctioning fuel into the pressurizing chamber, while the control valve controls closing timing, at which the connection between the suction passage and the pressurizing chamber is closed by the control valve in a delivery stroke, during which the plunger is driven toward a delivery side for delivering the fuel out of the pressurizing chamber. The pump body forms a release passage that is communicated with the suction passage. The release passage relieves the fuel, which is pressurized by the plunger, from the pressurizing chamber before the closing timing during the delivery stroke.