Solenoid Valve Nonmagnetic Cylindrical Portion Eddy Current Reduction
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Solution Overview
Problem
Conventional solenoid valves with magnetic throttles experience reduced magnetic attractive force due to magnetic flux leakage, leading to impaired valve element response when the coil is de-energized, while nonmagnetic portions can cause eddy currents that retain magnetic flux and delay valve actuation.
Innovation Solution
A solenoid valve design featuring a movable core, a magnetic opposed portion, and a nonmagnetic cylindrical portion with specific thickness and cross-sectional area ratios to minimize eddy currents and promptly eliminate magnetic flux when the coil is de-energized, enhancing valve response by reducing the nonmagnetic cylindrical portion's thickness and optimizing the magnetic circuit's cross-sectional areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a magnetic throttle is used to prevent magnetic short-circuiting, then magnetic attractive force is improved, but magnetic flux leakage occurs and response time deteriorates
Solution Approach 1:
The invention removes the magnetic throttle component entirely and replaces it with a nonmagnetic cylindrical portion. This extraction eliminates the source of magnetic flux leakage while still preventing magnetic short-circuiting between the movable core and stationary core through the nonmagnetic barrier, thereby resolving the contradiction between maintaining magnetic attractive force and preventing flux leakage.
Solution Approach 2:
The invention changes the material parameter of the throttle portion from magnetic material to nonmagnetic material. This parameter change fundamentally alters the magnetic circuit behavior, preventing both magnetic short-circuiting and flux leakage simultaneously, thus improving valve response time while maintaining adequate magnetic attractive force.
2Force
If a nonmagnetic portion is used to prevent magnetic short-circuiting, then magnetic attractive force is improved, but eddy currents arise and response time deteriorates
Solution Approach 1:
The invention changes the geometric parameter of the nonmagnetic portion by reducing its thickness to 0.6 mm or less. This parameter change reduces the volume available for eddy current circulation, thereby minimizing eddy current effects while still maintaining the nonmagnetic barrier function to prevent magnetic short-circuiting.
Solution Approach 2:
The invention applies local quality by making the nonmagnetic cylindrical portion have specific dimensional characteristics (thickness of 0.6 mm or less) only in the critical region where it interfaces with the magnetic circuit. This localized optimization minimizes eddy currents in the most critical area while maintaining the overall structural function.
3Loss of time
If the nonmagnetic cylindrical portion thickness is reduced, then eddy currents are minimized and response time is improved, but structural strength may deteriorate
Solution Approach 1:
The invention optimizes the thickness parameter of the nonmagnetic cylindrical portion to be 0.6 mm or less, finding the optimal balance point where eddy current effects are minimized while structural strength remains adequate. This parameter optimization resolves the contradiction by identifying the threshold value that satisfies both performance and structural requirements.
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 design ensures quick actuation of the valve element when de-energized, reducing valve-closing time and improving response by minimizing eddy currents and maintaining control over fuel injection quantity, thereby reducing fuel consumption.
Implementation Method 1
a coil located around an outer circumferential periphery of the nonmagnetic cylindrical portion, the coil being configured to generate magnetic attractive force between the magnetic opposed portion and the movable core when being energized
Implementation Method 2
in the present structure, an eddy current may arise in the nonmagnetic portion when the coil is de-energized and magnetic flux quickly reduces in the gap
Data Source
AI summary
A solenoid valve includes a movable core, a magnetic opposed portion opposed to the movable core, a nonmagnetic cylindrical portion, a first magnetic cylindrical portion axially close to the movable core, and a second magnetic cylindrical portion located radially outside of the magnetic opposed portion. The nonmagnetic cylindrical portion surrounds radially outside of a gap between the magnetic opposed portion and the movable core. A coil is provided radially outside of the nonmagnetic cylindrical portion. A thickness t of the nonmagnetic cylindrical portion, a cross-sectional area S1 of the magnetic opposed portion, and a total cross-sectional area S2 of both the magnetic opposed portion and the second magnetic cylindrical portion having the thickness t satisfy the relationships of t≦0.6 mm and 0.55≦(S1/S2).