Optimization Technology of Magnetic Circuit for Linear Solenoid

A linear solenoid is an important element part which hydraulically controls a VVT(Variable Valve Timing) system, etc. The demanded feature of the solenoid is that it performs an electromagnetic force output being constant regardless of the stroke and being proportional to coil current. In order to minimize the size, the electromagnetic force per volume has to be improved but the linearity is contradictory to the electromagnetic force and the consistency therebetween is very difficult to be achieved. Currently, the magnetic field analysis is repeatedly performed with trial and error to eventually obtain optimal designing of a magnetic circuit. We will introduce herein the results of our development in optimization technology for a magnetic circuit which can be used to effectively design a compact linear solenoid upon development of a new VVT system for a vehicle.