Abstract
Solenoid valves (SV) are used in common rail (CR) diesel injectors to initiate and stop the fuel injection. For modeling the magnetic part of the SV, often empirical or physically-based models, relying on static measurements of the magnetic force, are reported in literature.
The first objective of this study is to test different approaches on their ability for describing the static magnetic force of a considered SV of a CR diesel injector. The second aim is to evaluate whether the dynamic behavior of the SV can be reproduced by a simulation model of the SV, when a static magnetic force model is used as magnetic submodel.
For an experimental evaluation of the static magnetic force of the considered SV as function of current and air gap, a test bench is designed and set up during this study. Using the experimental data as reference, different magnetic force models known from literature are investigated and compared. For evaluating the dynamic behavior of the SV, dynamic measurements of the pin displacement are carried out. A simulation model of the SV is derived and implemented in Matlab/Simulink, which consists of a mechanical and a magnetic submodel. A static magnetic force model is used as magnetic submodel, without any further considerations of solenoid dynamics. The measured data are compared to simulation data.
In the proposed paper the main characteristics of the test bench, which has been implemented for measuring the static magnetic force of the SV, are presented. It is shown that some of the approaches from the literature are inapplicable to describe the measured static magnetic force data of the considered SV well in the relevant operation range of the SV. Appropriate approaches are specified together with all needed coefficients. It is shown, that the dynamic behavior of the considered SV cannot be accurately described by a simulation model that uses a static magnetic force model as magnetic submodel without any further considerations of dynamic effects of the solenoid.
KEYWORDS – common rail diesel injector, magnetic force measurement, solenoid valve, test bench, simulation