Computational Analysis of DI Pump Ticking Noise Excited By Solenoid Valve Impact

Stringent CAFÉ (Corporate Average Fuel Economy) regulations are being imposed by OEMs (Original Equipment Manufacturers) to reduce energy consumption and emissions. As a consequence, the past decade has seen a rapid growth for the gasoline DI (Direct Injection) engines market due to the benefits of the improved fuel economy, low emissions and high power density. However, the major drawback of the DI fuel system is the NVH (Noise, Vibration and Harshness) issues. The radiated impulsive ticking noise excited by the solenoid valve impact in DI pump is extremely annoying to the driver and passenger when the vehicle is idling, which should be taken into account in the early design stage. Thus, a 3D CAE simulation model of the DI pump is developed to evaluate the vibration due to the solenoid valve impact. The dynamic contact force is evaluated and the surface vibration is then utilized as the boundary condition to the noise radiation computation using finite element method (FEM). The acoustic model is setup in the simulation model and the noise radiation in the near field microphones is computed. The simulated sound pressure levels are compared to the test data and corresponding suggestions are proposed to improve the correlation.