Diesel fuel valve actuator - QuickField simulation example
This simulation example is prepared by Nils Pahlbäck.
The original performance of the fuel valve is generally adequate, but in cases of prolonged inactivity the valve cease to function due to a stuck plunger.
The suggested solution is to increase the flux in the
circuit to achieve an increased retraction force on
the plunger. The outer dimensions can not be
changed, and the coil current can not be increased
due to heat generation. The actuator is designed for 100% ED.
How to increase plunger retraction force under strict geometric and thermal constraints?
Answer Typical applications Geometry
Given
Task
Solution
Results
Engineering question
Add a permanent magnet into the solenoid circuit to increase the flux gradient, then perform a nonlinear magnetostatic analysis in QuickField to compare the original and enhanced designs.
diesel fuel valves, solenoid actuators, hybrid electromagnetic devices, permanent-magnet relays
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Simulation problem
Problem Type
Axisymmetric problem of DC magnetics.
Current density j = 0.1 A/mm²
Ferrite magnet coercive force Hc = 195 kA/m, remnance Hc = 0.274 T.
Calculate and compare the force acting on the plunger with and without the permanent magnet.
The multi-turn winding is replaced with the equivalent total current.
As the permanent magnet B-H curve is linear, you should specify a constant value of magnetic permeability.
The relative magnetic permeability can be calculated from the remanence and coercive force values:
μ = Br / (μ0 · Hc) = 0.274 / (4π·10-7 · 195000) = 1.118.
The magnetic field distribution plot along the axis.
The total mechanical (Maxwell) force acting on the plunger is around 0.0483 N.
Video
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