Fuel Pump Throttle Mechanism for Pressure Maintenance
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Solution Overview
Problem
Existing high-pressure fuel pumps face challenges in maintaining fuel pressure in the accumulation chamber without decreasing it to compression chamber pressure, leading to inefficiencies in volume efficiency and pressure management.
Innovation Solution
A fuel pump design incorporating a discharge valve, a second passage with a valve seat, and a biasing unit, along with a throttle mechanism to restrict fuel flow from the accumulation chamber to the compression chamber, ensuring fuel pressure is maintained by controlling the flow through a sliding gap between the valve element and the passage wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a passage is formed by clearance between components to return fuel from accumulation chamber to compression chamber, then fuel pressure in accumulation chamber can be reduced when pump is stopped, but volume efficiency of the pump deteriorates due to fuel returning to compression chamber during operation
Solution Approach 1:
The invention extracts the pressure reduction function from the regular fuel return passage by providing a separate bypass passage that is opened only when needed (when pump is stopped), rather than having the main passage always open for pressure equalization
Solution Approach 2:
The invention introduces a bypass passage as an intermediary route that allows selective pressure reduction without affecting the main fuel return path, using a valve mechanism to control when this intermediary path is active
2Loss of energy
If valve element and biasing unit are provided in the passage to maintain predetermined fuel pressure, then fuel pressure can be maintained without decreasing to compression chamber pressure, but device complexity increases
Solution Approach 1:
The invention merges the pressure control valve mechanism with the existing fuel return passage structure, integrating the valve element and biasing unit into the passage rather than adding completely separate components
Solution Approach 2:
The valve element serves multiple functions: it controls the bypass passage for pressure reduction, maintains sealing between accumulation and compression chambers, and works with the biasing unit to regulate fuel pressure automatically
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 maintains fuel pressure in the accumulation chamber, preventing fuel from returning to the compression chamber, thus enhancing the volume efficiency and pressure management of the high-pressure fuel pump.
Implementation Method 1
an elastic member (349) formed of a material being further elastic than the core member (343), the elastic member (349) surrounding an outer circumferential wall surface of the core member (343), the elastic member (349) being configured to apply predetermined surface pressure to both a portion between an inner circumferential wall of the elastic member (349) and the outer circumferential wall of the core member (343) and to a portion between an outer circumferential wall of the elastic member (349) and an inner circumferential wall defining the second passage (85b)
Data Source
AI summary
A housing has a compression chamber and a first passage, through which the compression chamber communicates with an accumulation chamber. A discharge valve is provided in the first passage and configured to open to supply fuel from the compression chamber to the accumulation chamber in response to increase in pressure in the compression chamber. A second passage is configured to communicate the accumulation chamber with the compression chamber via the discharge valve. A valve element allows fuel flow from the accumulation chamber to the compression chamber. A biasing unit biases the valve element to seat the valve element on a valve seat of the second passage. The sidewall of the valve element and the inner wall defining the second passage therebetween define a throttle midway through the second passage for restricting fuel flow from the accumulation chamber to the compression chamber.