In this article an attempt has been made in cylinder sector combustion CFD simulation of four stroke petrol engines using ANSYS fluent 2019 to obtain very useful results using a modelled engine. In order to improve engine quality, understanding on sector combustion properties in engine cylinder is of major importance because combustion condition significantly influences engine efficiency, Capabilities in providing optimum combustion conditions which include high optimum swirl ratio, and optimum tumble ratio in respective engine can result in enhancement of engine power and comfort, along with reduction of fuel consumption, exhaust emission and noise. The simulation is applied for a geometry with crank radius (55mm), connecting rod length (165mm), Engine speed (1800rpm), which is developed to study the effect combustion inside the cylinder. Piston starts from bottom dead center about 541degrees and the maximum pressure reaches at 716 degrees. The pressure increases from 542 crank angle degree to 716 crank angle degree and reaches its maximum value at 716 crank angle degrees. The Maximum pressure at the end of compression is 63.69Kpa and temperature is 1200K. The maximum penetration length of injection is occurred at crank angle 722 degree is 0.014mm.