Fuel Pump Nozzle Tilted Valve Guide for Pressure Drop
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Solution Overview
Problem
Fuel pump nozzles face issues with reliable operation at low feed power and delayed or increased pressure drop at the inlet, leading to potential uncontrolled fuel outflow during refueling, especially when the fuel feed pump is shut off.
Innovation Solution
The main valve is tilted into the closed position by a mechanism that reduces its tightness, ensuring reliable closure after the fuel feed pump is shut off, and allows pressure control to prevent excessive pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main valve is pressed tightly into the closed position to prevent fuel leakage, then the sealing reliability is improved, but the pressure drop at the inlet is delayed or increased, which may prevent the second automatic safety shut-off from triggering reliably
Solution Approach 1:
The valve guide is designed with an inclined surface that creates a tilted pressing action on the main valve. This inclined guide provides different sealing characteristics at different regions of the valve seat, allowing the valve to maintain adequate sealing while permitting sufficient pressure drop to trigger the safety shut-off mechanism.
Solution Approach 2:
The valve guide employs an asymmetric inclined surface rather than a symmetric vertical guide. This asymmetric design causes the main valve to be pressed tilted against the valve seat, creating an intentional imbalance in the sealing pressure distribution that allows pressure to bypass the valve sufficiently for the safety shut-off to detect and respond to low pressure conditions.
2Manufacturing precision
If the feed power is reduced to achieve precise quantity control, then the manufacturing precision of fuel quantity is improved, but the pressure at the inlet drops below the threshold, causing unintended triggering of the second automatic safety shut-off
Solution Approach 1:
The inclined valve guide creates localized variations in sealing pressure across the valve seat. This allows the system to maintain precise quantity control at reduced feed power while the tilted valve configuration ensures sufficient pressure drop occurs to prevent false triggering of the safety shut-off during normal low-power operation.
Solution Approach 2:
The valve guide's inclined surface allows the main valve to dynamically adjust its seating angle and contact pressure based on the incoming fuel pressure. During low feed power operation, the valve naturally tilts to maintain adequate pressure drop, while during high pressure operation, it achieves tighter sealing, creating a dynamic adaptation to varying operating conditions.
3Stress or pressure
If the main valve is tilted into the closed position with reduced tightness, then the pressure drop is sufficient to trigger the second automatic safety shut-off, but the sealing reliability is reduced, potentially allowing uncontrolled fuel outflow
Solution Approach 1:
The tilted valve configuration created by the inclined valve guide achieves localized sealing at specific regions of the valve seat while maintaining pressure drop pathways. This local quality approach ensures that the valve provides sufficient sealing to prevent uncontrolled outflow while simultaneously allowing adequate pressure reduction to trigger the safety shut-off mechanism.
Solution Approach 2:
The inclined valve guide acts as an intermediary mechanism that mediates between the conflicting requirements of sealing reliability and pressure drop. By tilting the main valve against the valve seat through this intermediate guide structure, the system achieves a balanced state where both sealing and pressure reduction functions are satisfied.
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 ensures reliable operation at low feed power, prevents fuel outflow, and reliably triggers the second automatic safety shut-off by reducing the sealing pressure to below the switching threshold, preventing unintended fuel dispensing.
Implementation Method 1
the main valve is pressed into the closed position in a tilted manner under the action of the mechanism for prestressing the main valve into the closed position in the full hose mode such that the tightness of said main valve is reduced
Data Source
AI summary
The subject matter of the invention is a fuel pump nozzle, with an inlet (2), a discharge pipe (3), a main valve for controlling the stream of liquid between the inlet (2) and discharge pipe (3), a switching lever (4) for actuating the main valve, a first automatic safety shut-off which moves the main valve into the closed position if the liquid level in a tank to be filled reaches a filling level sensor arranged in the region of the discharge pipe (3), a second automatic safety shut-off which moves the main valve into the closed position if the liquid pressure at the inlet (2) drops below a minimum value, and a mechanism (13) for prestressing the main valve into the closed position, said mechanism bringing about a variable opening cross section of the main valve depending on the liquid pressure at the inlet (2). According to the invention, the main valve is pressed into the closed position in a tilted manner under the action of the mechanism for prestressing the main valve into the closed position in the full hose mode such that the tightness of said main valve is reduced.