Predictive Engine Part Load Modeling for the Development of a Double Variable Cam Phasing (DVCP) Strategy

DVCP, a system with continuously adjustable intake and exhaust cam positions, was investigated in terms of residual gas content, intake manifold pressure, pumping losses and fuel economy by means of engine cycle simulation on a 16-valve 4 cylinder naturally aspirated SI engine at part load conditions. Using the simulation results a phasing strategy for part load operation with the primary emphasis on improved fuel consumption has been developed.

To verify simulation predictions subsequently, measurements were made at the test rig. It was found that cycle simulation was able to predict properly the behavior of the engine even far away from calibration point. The simulated and measured cam positions for maximum fuel economy matched. Test rig results showed that fuel economy improvement by DVCP is limited by residual gas content tolerance of the engine investigated.