Fuel Pump Inlet Valve Damping for Bounce-Free Closure
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Solution Overview
Problem
The high-frequency reciprocal movements of the inlet valve in fuel pumps cause undesirable bouncing and overshooting, leading to inefficiencies and damage to the valve and seat faces in fuel equipment of internal combustion engines.
Innovation Solution
An annular opening is created between the skirt and the pump body, forming a fluid communication that varies to act as a throttle, damping the valve member's displacements by using a female conical face on the skirt and a complementary male conical face on the pump body, which restricts the fuel flow and stabilizes the valve movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet valve moves at high frequency to control fuel flow, then the fuel pump efficiency is improved, but bouncing and overshooting occur causing valve damage and reduced reliability
Solution Approach 1:
The patent introduces a damping chamber and damping orifice that create a cushioning effect before the valve closes. The damping chamber accumulates fuel under the valve head, and the restricted flow through the damping orifice creates backpressure that cushions the valve closing impact, preventing damage while maintaining high-frequency operation
Solution Approach 2:
The damping chamber acts as an intermediary between the inlet valve and the fuel supply. It mediates the high-frequency valve movements by providing a controlled fuel reservoir and flow restriction, transforming the direct impact into a cushioned closing action that protects the valve and seat
2Productivity
If the inlet valve closes quickly to control fuel flow, then the fuel pump productivity is improved, but hammer impacts damage the valve and seat faces
Solution Approach 1:
The damping chamber is positioned to accumulate fuel before the valve closes, creating a cushioning layer. The damping orifice restricts fuel flow into this chamber, generating backpressure that cushions the valve closing impact, thereby preventing hammer damage while allowing quick valve operation for maintained productivity
3Productivity
If the valve opens quickly to allow fuel entry, then the fuel pump efficiency is improved, but bouncing occurs re-opening the inlet and altering efficiency
Solution Approach 1:
The damping chamber creates a feedback mechanism where fuel pressure builds up during valve opening and provides counterpressure during valve closing. This feedback stabilizes the valve movement by preventing bouncing and overshooting, ensuring clean valve closure while maintaining efficient fuel flow during the open phase
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 reduces bouncing and overshooting, enhancing the efficiency and longevity of the fuel pump by minimizing impacts and maintaining the integrity of the valve and seat components.
Implementation Method 1
an inlet valve that urged toward a closed position of said inlet by a spring compressed between a disc-like seat member fixed to said valve and a lower seat defined on the pump body
Implementation Method 2
the opening of said fluid communication varies in use, and it defines a throttle damping the displacements of the valve member
Data Source
Figure 1~2
Figure 3~4
AI summary
An inlet valve arrangement (20) of a fuel pump (10) comprising a valve member (22) having a stem (26) and a head (28) wherein, a spring (32) compressed between a lower seat (34) defined on the pump body and, a seat member (38) fixed to said stem. The spring seat member (38) has a disc-like base (40) and, a skirt member (42) defining a spring chamber (46) wherein said spring is arranged, said skirt member (32) axially extending to a distant annular end (44) cooperating with an annular face (50) of the pump body surrounding the lower seat (34).