Title: Split ratio control in mini-dilution tunnels for measurement of steady-state and transient emissions from heavy duty diesel engines

Authors: Mridul Gautam, Robert C. Smith II, Eric Miller, Sandeep Mehta, N. Hirakouchi, T. Shouji

Addresses: Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506, USA. ' Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506, USA. ' Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506, USA. ' Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506, USA. ' Mitisubishi Motors R&D of America, Bridgeport, NJ 08014, USA. ' Mitsubishi Motors Corporation, Japan

Abstract: A 91-tube multi-tube-type mini-dilution tunnel with and without a split ratio control unit was used to study the emissions from a heavy duty diesel engine, operated over several steady-state modes and transient test cycles. The split ratio, or the gas induction ratio, relates the volume of sampled raw exhaust to the total volume of engine exhaust that is generated. Determination of the split ratio and the ability to maintain this ratio around a certain theoretical value, 1/91 in the study, was critical to the entire sampling process. Results presented herein, demonstrate the ability of the split ratio control unit to improve dramatically the splitting accuracy of the 91-tube splitter, over both steady-state and transient cycles. Even when operated over severe changes in engine conditions of the transient cycles, the split ratio control unit was able to maintain an average pressure differential of nearly zero. However, the transient response of the PID controller needs further improvements.

Keywords: heavy duty diesel engines; mini-dilution tunnels; split ratio control; steady-state emissions; transient emissions; exhaust emissions; vehicle emissions; heavy vehicles.

DOI: 10.1504/IJHVS.1998.054623

International Journal of Heavy Vehicle Systems, 1998 Vol.5 No.3/4, pp.379 - 398

Published online: 18 Jun 2013 *

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