Fuel Injector Guide Element S-Shape Deformation
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Solution Overview
Problem
In fuel injectors with high system pressures, asymmetrical force influences and flow conditions lead to transverse forces on the guide element, causing increased wear and friction due to the tight fit between the guide element and magnet armature, which restricts movement and leads to premature wear.
Innovation Solution
The guide element is designed with at least two axially spaced weakened areas, allowing it to deform in an 'S' shape under transverse forces, reducing friction and wear by enabling larger transverse movements with minimal frictional force, and ensuring unimpeded movement without contact with other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the guide element is designed with a tight fit between outer diameter and bore diameter, then fuel leakage is prevented, but wear and friction increase under transverse forces
Solution Approach 1:
The guide element is segmented into multiple sections with different cross-sectional areas, creating weakened areas that allow localized deformation. This segmentation enables the guide element to bend in an S-shape under transverse forces, maintaining the tight fit in non-deformed sections to prevent fuel leakage while allowing deformed sections to accommodate transverse movements and reduce wear.
Solution Approach 2:
The guide element transitions from a rigid structure to a dynamically adaptable one by incorporating weakened areas that enable controlled deformation. Under transverse forces, the guide element dynamically changes its shape to an S-curve, allowing the magnet armature to move laterally without increasing friction, while the overall tight fit structure maintains its integrity for fuel containment.
2Strength
If the guide element is made rigid to maintain structural integrity, then mechanical strength is improved, but transverse movement capability is reduced leading to increased wear
Solution Approach 1:
The guide element exhibits non-uniform local quality with weakened areas having reduced cross-sectional areas compared to other sections. This local variation in structural properties allows the guide element to maintain overall mechanical strength while creating specific zones that can deform under transverse forces, enabling lateral movement of the magnet armature without compromising the guide element's structural integrity.
3Ease of operation
If the guide element is designed with weakened areas for flexibility, then transverse movement is improved, but structural rigidity is reduced
Solution Approach 1:
The guide element is divided into rigid sections and flexible weakened sections. The rigid sections maintain structural integrity and prevent fuel leakage, while the weakened sections provide flexibility for transverse movement. This segmentation creates a composite structure that balances rigidity and flexibility, allowing the guide element to deform in an S-shape under transverse forces while maintaining overall structural stability.
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 reduces wear and friction between the guide element and valve member, allowing for smooth operation even under high axial compressive forces, maintaining the injector's performance and longevity at pressures above 2000 bar.
Implementation Method 1
a magnet coil which, when energized, causes the valve element to be lifted out of its position closing the drain hole
Implementation Method 2
The magnet armature is subjected to a force by a compression spring in the direction of the closed position of the valve element
Implementation Method 3
the guide element to deform in the form of an 'S' when a transverse force occurs
Implementation Method 4
the pressure of the control chamber always acts on the guide element. This hydraulic pressure force is transmitted from the guide element via an element fixed to the housing into the injector housing
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a fuel injector (10) comprising an injector housing (11) in which an injection member (20) is arranged longitudinally displaceable along a longitudinal axis (22), comprising a control chamber (35) hydraulically connected to a high-pressure chamber (25) of the injector housing (11), which control chamber can be hydraulically relieved via a drain hole (30) in the direction of a low-pressure chamber (42) of the injector housing (11), wherein the flow rate of pressure medium through the drain hole (30) can be controlled by means of a valve element (40), wherein the valve element (40) is arranged axially displaceable in a preferably rod-shaped guide element (65; 65a) which plunges into a hole (60) of the valve element (40) and is supported on the side facing away from the valve element (40) on a stationary housing element (55), and wherein the guide element (65; 65a) has a first attenuation region (71) in a region between a guide section (61) of the guide element (65) in the valve element (40) and the stationary housing element (55), in which attenuation region the cross section of the guide element (65; 65a) is reduced.