Rotary Fuel Pump Advance Arrangement Air Venting
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Solution Overview
Problem
Current rotary fuel pumps lose control over the advance piston when a large volume of air is introduced into the system, leading to potential damage and leakage due to air being swept into the advance arrangement, causing the advance piston to reciprocate rapidly and lose correct advance functionality.
Innovation Solution
A first vent line is provided to vent air from the speed-dependent fuel pressure line, with a collection chamber and a second vent line to ensure controlled operation of the advance arrangement, using a larger first vent line and a smaller second vent line with a helical groove to preferentially vent air while minimizing fuel flow, thereby reducing air introduction and protecting the advance piston.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional rotary fuel pump is used without air venting, then the pump structure remains simple, but air accumulation causes advance piston loss of control and potential damage
Solution Approach 1:
The venting system is segmented into two separate vent lines with different functions: a first vent line with larger cross-sectional area for primary air venting, and a second vent line with smaller cross-sectional area for secondary venting and fuel return control. This segmentation allows each vent line to be optimized for its specific function while working together to solve the air accumulation problem.
Solution Approach 2:
A collection chamber is introduced as an intermediary component between the two vent lines. This collection chamber receives air from the first vent line and provides a controlled interface for the second vent line, allowing air to be progressively vented while preventing direct air intrusion into the advance arrangement. The collection chamber acts as a buffer and control point in the venting system.
2Object-affected harmful factors
If air venting is implemented through a single vent line, then the system is simpler, but air cannot be effectively separated from fuel and the advance arrangement remains vulnerable
Solution Approach 1:
The two vent lines are designed with different local qualities - the first vent line has a larger cross-sectional area optimized for air venting, while the second vent line has a smaller cross-sectional area optimized for controlled fuel return and secondary air venting. This local differentiation allows each component to be optimized for its specific function in the air-fuel separation process.
Solution Approach 2:
The first vent line provides preliminary air venting action by removing the bulk of air from the system before fuel reaches the advance arrangement. The collection chamber then provides a transition zone, and the second vent line provides final controlled venting. This preliminary action prevents air from reaching the advance piston before it can cause damage.
3Productivity
If the vent line cross-sectional area is large, then air venting efficiency is improved, but fuel leakage through the vent line increases
Solution Approach 1:
The venting function is segmented between two vent lines with different cross-sectional areas. The first vent line uses a larger cross-sectional area for high-efficiency air venting, while the second vent line uses a smaller cross-sectional area to minimize fuel leakage. This segmentation allows the system to achieve both high air venting efficiency and low fuel loss by optimizing each vent line's dimensions for its specific function.
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
The solution effectively reduces the risk of air-induced damage to the advance piston by venting air from the speed-dependent fuel pressure line, ensuring controlled operation and maintaining correct advance functionality even when air is present, thus preventing potential damage and leakage.
Implementation Method 1
a first vent line is provided for venting air from the speed dependent fuel pressure line
Implementation Method 2
The second vent line can have a relatively small cross-sectional area to define a viscous leak path for inhibiting the flow of fuel from the collection chamber to the cam box
Data Source
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AI summary
The present invention relates to a rotary fuel pump (101). The pump (101) has a rotor (107) and at least one pumping element (115) for supplying high pressure fuel. A cam box (123) containing a cam arrangement (103) is provided for actuating the at least one pumping element (115). A speed dependent fuel pressure line (129) is provided for supplying speed dependent fuel pressure to an advance arrangement (125) for adjusting the timing of fuel delivery by the pump (101). A first vent line (131) is provided for venting air from the speed dependent fuel pressure line (129). The present invention also relates to an advance arrangement (125) for a fuel pump (101) and a rotor (107) for a fuel pump (101).