IMPACT OF THE MILLER CYCLE IN THE EFFICIENCY OF AN FVVT (FULLY VARIABLE VALVE TRAIN) ENGINE DURING PART LOAD OPERATION

摘要

In automotive application, spark ignition engines are, most of the time, part load operated, especially in city traffic and this is the most common operation situation of those engines. By eliminating the throttle from load control, the fuel economy can be much improved. One already known mean of load control is the Miller cycle, implemented by valve timing variation. In this paper, the part load efficiency of a two-liter gasoline engine is compared and analyzed, using three different means of load control: late intake valve closure (LIVC), early intake valve closure (EIVC) and throttle.