A. Selamet M. S. Croy
Dept. of Mech. Eng. and Appl. Mech., Univ. of Michigan, Ann Arbor, MI 48109-2125
R. A. Kach J. M. Novak
Ford Motor Co., Dearborn, MI 48121
In vehicle exhaust systems, the sound attenuation and the reduction of flow losses are often competing demands. The present experimental study considers a full vehicle exhaust system and investigates both the sound attenuation and the flow performance of production configurations including the catalyst, the resonator, and the muffler. Dynamometer experiments have been conducted with a firing Ford 1.9-Liter I4 Escort engine with speeds ranging from 1000 to 5500 rpm. Measurements including the flow rates, the temperatures, and the absolute dynamic pressures of the hot exhaust gases at key locations (upstream and downstream of every component) with fast-response, water-cooled piezoresistive transducers facilitate the calculation of acoustic performance of each component, as well as the determination of flow losses caused by these elements and their influence on the engine performance. The present study describes the experimental aspects of an extensive effort toward employing nonlinear fluid dynamic models in the time domain for the prediction of the acoustic and power performance of firing internal combustion engines with full production exhaust system.