Influence of Auxiliary Exhaust Valve With Variable Timing on Spark Ignition Engine Performance

Abstract

New Variable valve timing strategy based on using auxiliary valve having variable timing (VVT) is used in this study. The valve is driven by a new variable valve timing mechanism constructed for this purpose. The auxiliary valve acts as an exhaust valve and the experiments and simulation model are carried out at different loads. The results show that engine performance is improved at full load and worsens at part loads. The study proves that using an auxiliary exhaust valve having variable timing is not recommended in engines applications. NOMENCLATURE A c p , c v D _ Mass fraction, position coordinate Greek Symbols Crank position angle (degree) Combustion duration (degree) Boltzman constant Density (kg/m 3) Equivalence ratio Supscripts Burn Unburn wall Superscripts Derivative with time (d/dt) Molar quantity