engleski

The Influence of Fully Variable Valve Timing on the Performances of Automotive Otto Engine

The purpose of this paper is to present the achievements in the field of fully variable valve actuation. The emphassis is put on the analyssis of existing valve control strategies, the design of the calculation model of a 4-stroke, spark ignited engine and the simulation under specified working conditions solved using ''AVL-Boost'' package. The influence of variable valve actuation and unthrottled engine operation on the gas exchange, mixture preparation and high-pressure combustion process is duscussed in order to estimate the fuel economy potential. This paper shows potential fuel economy benefits via unthrottled operation (WOT) an cylinder deactivation for various working conditions, mainly for the operating point of 200 rpm and BMEP of 2 bars, which represent one of the most common part load conditions. The result of simulations conducted on several engine models show the fuel consumption advantages of approximately 10% for the operation strategy ''Early Intake Valve Closing'' (EIVC) and an overall reduction of 20% in the case of 2-Cylinder deativation mode, compared to the conventional 4-cylinder, 4-stroke Otto engine.

internal combustion engines; spark ignited; camless; fual consumption

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