Electromagnetic Fuel-Injection Valve Non-Magnetic Guide Bush
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Solution Overview
Problem
Electromagnetic fuel-injection valves face challenges in quickly eliminating residual magnetism and improving valve-closing responsiveness during coil de-energization, which affects the stability and responsiveness of the valve assembly.
Innovation Solution
Incorporating a non-magnetic or weakly magnetic guide bush with higher hardness than the fixed core, which projects beyond the attracting face of the fixed core, and a sliding member with equal hardness, along with spherical surfaces for reduced friction, supports the valve assembly and enhances responsiveness by avoiding direct core contact and facilitating smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the fixed core and movable core are made of magnetic materials for electromagnetic actuation, then the electromagnetic force is sufficient to open the valve, but residual magnetism remains after de-energization which slows valve-closing responsiveness
Solution Approach 1:
A non-magnetic guide bush is introduced as an intermediary component between the movable core and the magnetic field source. The guide bush has a front end that projects beyond the attracting face of the fixed core, creating a physical stop that defines the valve-opening limit and forms an air gap. This intermediary structure allows the magnetic cores to be non-magnetic (improving closing responsiveness) while still providing sufficient electromagnetic force through the air gap during actuation.
2Stability of the object's composition
If the support span for the valve assembly is extended beyond the distance between valve seat and fixed core, then the valve assembly stability is improved, but the structure becomes more complex
Solution Approach 1:
The guide bush serves multiple functions simultaneously: it provides mechanical guidance for the movable core, defines the valve-opening limit through its projecting front end, forms an air gap to reduce residual magnetism, and supports the sliding member for enhanced stability. By consolidating these functions into a single component, the structure achieves extended support span and improved stability without proportionally increasing complexity.
3Speed
If the guide bush is made of non-magnetic or weakly magnetic material to eliminate residual magnetism, then valve-closing responsiveness is improved, but the guide bush may have insufficient wear resistance
Solution Approach 1:
The guide bush is constructed from composite materials or material combinations that provide both non-magnetic properties and high wear resistance. The sliding member is made of material with hardness substantially equal to the guide bush, creating a matched wear-resistant interface. This composite approach allows the guide bush to maintain its non-magnetic characteristic for quick closing while achieving sufficient durability through material science.
4Ease of operation
If the spherical surface is provided on the sliding member for line contact with the guide bush, then friction is reduced and operation is smoothed, but manufacturing precision requirements increase
Solution Approach 1:
A spherical surface is provided on the outer periphery of the sliding member to create line contact with the inner peripheral face of the guide bush during operation. This spherical geometry reduces friction compared to point or surface contact, and smooths the operation of the valve assembly. The spherical shape naturally distributes contact stresses and accommodates minor misalignments, making the precision requirements more manageable despite the curved geometry.
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 configuration stabilizes the valve assembly's opening/closing attitude, improves abrasion resistance, and balances fuel injection flow rate characteristics while simplifying the structure, ensuring quick elimination of residual magnetism and enhanced responsiveness.
Implementation Method 1
a coil that is disposed on an outer periphery of the fixed core and makes the valve body open by making the fixed core attract the movable core by energization
Implementation Method 2
a non-magnetic or weakly magnetic guide bush is fixedly provided on an inner periphery of the fixed core... quicken elimination of residual magnetism in the fixed core and the movable core at the time of de-energization of the coil
Data Source
AI summary
In the disclosed electromagnetic fuel-injection valve: a non-magnetic or weakly magnetic guide bush (19) is affixed at the inner periphery of an immobile core (6); the front end of the guide bush (19) protrudes from the suction surface (6a) of the immobile core (6); during excitation of a coil (37), by means of a mobile core (16) being caused to contact the front end of the guide bush (19), the opening boundary of a valve body (15) is defined, and an air gap (g) is formed between the immobile core (6) and the mobile core (16); and a sliding member (20) that is slidably borne at the inner peripheral surface of the guide bush (19) is provided to a valve assembly (V). As a result, a structure-simple electromagnetic fuel injection valve is provided wherein the opening/closing postures of the valve body can be effectively stabilized, and moreover at the time of demagnetization of the coil, valve closing responsiveness can be favorably obtained.