The demand for fuel-efficient, eco-friendly products is growing steadily and due to the economic crisis at the same time all the automotive industries have to reduce the costs.
The contribution to high-performance gasoline engines and their emission reduction is given by an improvement of the dynamic performance of the injector in terms of reduction of the minimum mass flow rate and the maximum operating pressure.
The main responsible of the opening and the closing phase dynamics of a Direct Solenoid Injector is the force generated by the magnetic circuit and therefore its layout has been identified as a possible zone of improvement of a new injector.
A FEA ANSYS/Emag 2D model with moving mesh of the XL3 injector magnetic circuit has been set up. The model has been used in a voltage feed transient simulation in which the ECU logic has been programmed and utilized in order to control the current profile that drives the injector.
The magnetic force generated by the circuit on the armature is the output of the simulation. The model takes into account the dynamic behavior of the injector: at each time step, the external forces (hydraulic, squish/sticking forces, spring load and friction) acting on the components have been calculated and the position of the armature has been updated.
The model has been correlated and afterwards used in a modeFRONTIER multi-objective optimization in order to maximize the operating pressure and minimize the injected quantity varying the geometrical and electrical parameters. Almost 500 different configurations have been calculated with a total number of simulations near 2000 in two weeks of computing time.
After the optimization, 3 configurations have been built and tested reducing greatly the experimental costs and the time to market. |
