Fuel Injector Seal Member Balancing Axial Thrust
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Solution Overview
Problem
Existing fuel injectors for internal-combustion engines are inefficient and unreliable, particularly when regulating injection with small strokes or lifts of the open/close element, due to axial thrusts generated by fuel pressure causing elastic deformations in the valve body, which disrupt the intended positioning of the open/close element and electric actuator.
Innovation Solution
A fuel injector design featuring a seal member carried by the valve body, made of plastic material, which balances the axial thrusts from fuel pressure, preventing elastic deformations and maintaining consistent positioning of the valve body components by distributing the thrusts equally in opposite directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal member is carried by the injector body, then the fuel pressure generates axial thrust on the valve body causing elastic deformation, but the positioning of the open/close element and electric actuator becomes inaccurate
Solution Approach 1:
The seal member is inverted from being carried by the injector body to being carried by the valve body. This inversion changes the force transmission path: instead of fuel pressure acting on the valve body through a stationary seal, the seal moves with the valve body, allowing the fuel pressure thrust to be balanced by the resilient means without causing deformation of the valve body's critical positioning features.
Solution Approach 2:
A resilient means (spring element) is introduced to provide a counterbalancing force against the axial thrust generated by fuel pressure on the seal member. This counterforce compensates for the pressure-induced thrust, preventing elastic deformation of the valve body and maintaining accurate positioning of the open/close element and electric actuator throughout operation.
2Reliability
If the seal member is made of elastomeric material, then fluid-tight sealing is achieved, but the axial thrust from fuel pressure deforms the valve body
Solution Approach 1:
The resilient means acts as an intermediary element between the fuel pressure thrust and the valve body structure. It absorbs and counterbalances the axial thrust forces, preventing them from being transmitted to the valve body and causing deformation. This intermediary mechanism preserves both the sealing effectiveness and the manufacturing precision of the valve body components.
3Manufacturing precision
If the elastic deformations are compensated in the setting stage, then the positioning accuracy improves, but the deformations vary with instantaneous fuel pressure and cannot be fixed
Solution Approach 1:
The system transitions from a static compensation approach (fixed setting) to a dynamic compensation approach. The resilient means continuously adapts to varying fuel pressure conditions, providing real-time counterbalancing of axial thrusts. This dynamic mechanism maintains positioning accuracy across the full range of operating pressures without requiring re-setting or sacrificing adaptability.
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 enhances the efficiency and reliability of the fuel injector by maintaining geometrical invariance and consistent positioning of the valve body components, ensuring stable operation irrespective of fuel pressure variations.
Implementation Method 1
an elastic body (24) which exerts an elastic thrust on the open/close element (43)
Implementation Method 2
the pressure of the fuel contained in the annular chamber (30), generating an axial thrust directed towards the injector body (2)
Data Source
AI summary
A fuel injector for an internal-combustion engine houses, in a hollow injector body of its own, an injection-control valve, the valve body of which delimits, together with the injector body, an annular chamber designed to receive a fuel under pressure, and insulated in a fluid-tight way by a seal member carried by the valve body and made of plastic material.