Intake port flow study on cylinder head using flowbench

Abstract

Homogeneous air-fuel mixture that enters the combustion chamber during intake process can tremendously optimize the engine performance output. There are a number of factors that affect the mixture, but this study focuses on the flow through a cylinder head port. This study caters the shape and condition of a 1.6-liter Spark Ignition (SI) gasoline engine cylinder head after modification process. The modification consists of porting and polishing jobs. Effects of modification have been experimentally tested by opening the valve lift with significant value, by calculation using SuperFlow SF 600 FlowBench machine. Since flow losses are caused by port expansion rather than contraction, the greatest flow loss in the intake port is due to expansion of air out of the valve. The air flow through the engine is directly controlled by the valve lift, so greater flow should occur at the maximum valve lift at least up to a certain point. The experiment covers the intake value of flow rate due to the valve lift and Cd (Discharge coefficient). From this experiment, the results obtained show that flow is reduced in the cylinder head installed with runner and air box compared to cylinder head without installation of those parts. Modified cylinder head provides 12.7% increment of flow at maximum valve lift compared to standard cylinder head. In term of discharge coefficient, modified cylinder head also provides higher discharge coefficient values compared to standard cylinder head, which is 0.94 and 0.82, respectively at maximum valve lift. It is proven by experimental result that porting and polishing intake port area works can significantly increase the flow into engine and increase the engine horsepower.