Electromagnetic valves excellent in sealing properties and resistant to sliding are often used in powertrain equipment installed in gasoline- or diesel-engine vehicles. An electromagnetic valve has the function of moving internal valve members by means of electromagnetic force generated by the application of a voltage and thereby changing the flow path. When an electromagnetic valve operates, however, the valve members impact with one another, emitting impact noise caused by it. With the requirement for low noise in electromagnetic valves having become stricter recently from the viewpoint of comfort in the passenger compartment, predicting the noise is needed at the design stage.
With this background, this paper describes the development of a 1D model of impact force that will enable the noise and the product performance to be examined simultaneously for a GDI (gasoline direct injection) high pressure pump. In contrast to the conventional model in which a movable member is taken as a mass point with a spring and a damper placed at the impact section, this paper proposes a technique in which a spring-mass model with plural mass points is defined a basis on an eigenvalue of the movable member, verifying both models using measurement. In comparison with the conventional model, the proposed model can more exactly calculate the eigenvalues each of the three impact states in the opening operation of an electromagnetic valve. This allows one to improve that the accuracy in calculating the time characteristics of the force.
This paper, in addition, gives cases of use of the developed model in studying the reduction of the force. Reducing the stiffness of the member exposed to impact force enabled the reduction in the high-frequency components of the force to be calculated with high precision, and the accompanying reduction in impact noise was confirmed on the actual machine.
