Fuel Injection Valve Plating Thickness for Responsivity
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Solution Overview
Problem
Existing fuel injection valves for internal combustion engines face challenges in enhancing valve-closing response while maintaining durability and valve-opening responsivity, as thick plating on collision portions increases the magnetic gap, and complex plating work is required for uneven surfaces.
Innovation Solution
A fuel injection valve design with annular collision portions on the stationary and movable cores, where the plating is thicker on collision areas and thinner on non-collision areas, reducing the height of collision portions and maintaining sufficient plating thickness for durability, thereby minimizing the magnetic gap and fluid gap, and simplifying the plating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick plating is applied on collision portions to enhance durability, then anti-wear property is improved, but magnetic gap increases and valve-opening responsivity deteriorates
Solution Approach 1:
The patent applies different plating thicknesses to different regions of the core end face. Specifically, the collision portion (annular protuberance) receives thick plating for durability, while the non-collision portion receives thin or no plating to minimize magnetic gap. This local differentiation resolves the contradiction by optimizing each region's plating thickness according to its specific functional requirements.
2Speed
If protuberances are provided on opposed face of movable core to reduce squeeze effect, then valve-closing response is improved, but collision load is concentrated and durability deteriorates
Solution Approach 1:
The patent provides protuberances only on the movable core's opposed face, while the stationary core maintains a flat surface. This asymmetric arrangement concentrates the collision load on the protuberance tips, which are reinforced with thick plating. The flat stationary core surface distributes the collision load more evenly, preventing excessive wear on either component and resolving the durability issue while maintaining improved valve-closing response.
3Manufacturing precision
If complex masking work is performed for non-plating portions to create uneven surface, then fluid gap control is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of creating non-plating portions through complex masking processes, the patent inverts the approach by designing the core geometry itself to create the desired uneven surface. The annular protuberances are formed as integral parts of the core structure, and plating is applied selectively based on these geometric features rather than using masking to prevent plating in specific areas. This simplifies manufacturing while achieving the same fluid gap control.
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 improves valve-closing responsivity by reducing the fluid resistance force due to the squeeze effect, maintaining magnetic attraction force, and enhancing durability, while simplifying the plating process, resulting in improved dynamic range and fuel pressure performance.
Implementation Method 1
the movable core is magnetically attracted toward the stationary core side when the electromagnetic coil is energized
Implementation Method 2
the return spring applies the spring load to the movable core and the movable valve element in the direction of valve-closing
Implementation Method 3
a plating having anti wear property is provided on the annular end faces of the stationary core and the movable core
Data Source
AI summary
In a fuel injection valve, it is intended to enhance valve-closing responsivity while maintaining durability (anti wear property) of a collision portion between a stationary core and a movable core and valve-opening responsivity.An annular end face 106A of the movable core 106 in the fuel injection valve is provided with a collision portion 106C that collides to a stationary core 107 when the movable core is magnetically attracted toward the stationary core side and a non-collision portion that keeps a fluid gap between both cores at an area of an outer side or an inner side from the collision portion. The annular end faces of the stationary core and the movable core are coated with platings 30, 31 having anti wear property, and at least one of the platings of the stationary core and the movable core is formed in such a manner that the thickness thereof at the collision portion 106C is to be thicker and the thickness thereof at the non-collision portion is to be thinner.