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This paper presents a combined experimental and computational study of steady flow through a curved inlet port. Three-dimensional flow within the port and cylinder for the intake process has been simulated using the CFD code STAR-CD. Flow structures affected by the valve lift and port shape were predicted. Local static surface pressure was measured on a twice full size model of the port, valve and cylinder assembly. The static pressure maps from both measurement an computation provide detailed information on the intake port flow. The numerical predictions show an appreciable pressure recovery for a favourable flow passage between the valve seat and the valve head, which confirm earlier port design procedures. An optimum valve size for the present curved port was explored.

Emission studies and component analyses were carried out on Clear-fueled and MMT®-fueled 100,000 mile Escort vehicles from the Alliance study [SAE 2002-01-2894]. Previously reported analyses of these vehicles indicated that all differences in emission system performance could be attributed, with a 90% confidence level, to the engine cylinder head, spark plugs, oxygen sensors, and catalysts [SAE 2004-01-1084]. These parts from the Clear and MMT®-fueled vehicles were further analyzed to determine the root causes of the differences in emission system performance. The intake/exhaust valves, fuel injectors, and EGR valves from the cylinder heads were tested, individually and in groups, for differences in vehicle emission performance. Deposits from the exhaust valves of the MMT®-fueled vehicle were characterized by X-ray diffraction (XRD) and energy-dispersive X-ray spectrometry (EDX), and shown to resemble Mn3O4 with partial substitution of Zn2+ for Mn2+.