FLOW MEASUREMENTS IN THE EXHAUST SYSTEM OF A MOTORIZED ENGINE

摘要

Stereo Particle Image Velocimetry (SPIV) is used to measure the highly turbulent flow in the upstream region of the catalytic converter for a four stroke IC engine. These experiments are conducted for a motorized engine to investigate the feasibility of using SPIV for exhaust flow measurements in a firing IC engine in our future research. The results obtained here can also be used for validation of the CFD models. The measured flow is highly three dimensional, non-uniform with large magnitudes of turbulence indicating recirculating flow structures. These structures show signatures of jet flows coming out of the exhaust valves at all exhaust crank angles. The triangular shape and location for the end face of each exhaust runner pipe, the length and geometry of the runners also affect the flow mixing process upstream of the catalytic converter contributing to the complexity of this flow. Although majority of the exhaust flow passes through the catalytic converter, some will recirculate due to impingement of the exhaust jets on the surface of the catalyst.