DIYALA JOURNAL OF ENGINEERING SCIENCES

Abstract

The turbulent lean premixed combustion simulation is implemented in 4- stroke spark ignition (SI) engine. The Turbulent Flame speed Closure model (TFC) is used in different turbulent flow conditions. The model is tested for a variety of flame configurations such as turbulent flame speed, the heat release from the combustion and turbulent kinetic energy in the radial direction of the cylinder at 15.5 mm below the top dead center TDC point. The simulation performs in the three cases of the (intake / exhaust) valve timing. The exhaust valve case is an essential leverage on the turbulent flame specification. The combustion period is very important factor in SI engine which is controlled especially by the turbulent flame speed. The turbulent flame speed and heat transfer is ascendant less than 10 % and 3% in case of intake and exhaust valves are closed respectively. Moreover, the results show that the brake power enhances less than 4% and more than 40% with increase fuel temperature 60 K and engine speed 3000 rpm respectively.