Abstract
In most engines, valve timing represents a compromise between an engine's performances at low (engine torque) and high speed (engine power output) and also the fuel economy. In order to eliminate this disadvantage, the use of the variable valve timing was implemented. The variable timing system used for varying the timing in this analysis is the cam phaser. This device can only modify the cam lift position relative to crank angle position. The model used in the analysis is a gasoline single cylinder engine created using AVL Boost software, which is an advanced virtual engine simulation tool. This paper presents the simulation results obtained for 5 operating points. For each operating point, the valves’ overlap period was modified. In order to determine the influence of the variable valve timing upon the pumping losses, the volumetric efficiency and areas of the pressure-volume diagram were calculated. The areas of the pumping diagram were determined by using the Simpson's rule.
Keywords: Pumping Work, Volumetric Efficiency, Simulation, Internal Combustion Engine, AVL Boost