Some Critical Issues in the Steady Flow Testing of Cylinder Heads

There are considerable diversities in the techniques used for the steady flow testing of engine cylinder heads, and this paper presents and discusses the important issues involved in the flow bench experiment. The work aims to provide information necessary for setting up or upgrading the experimental system of cylinder head testing. The definitions of discharge/flow coefficients and swirl/tumble ratios are compared and examined, followed by the principles of selecting the test conditions such as pressure drop and flow rate. Techniques for measuring the angular flow momentum in cylinders are discussed and the link between the steady flow parameters and the engine combustion performance is highlighted. Some conclusions and recommendations are drawn from the discussion.