Development of naval diesel engine duty cycles for air exhaust emission environmental impact analysis.

摘要

A strategy for testing naval diesel engines for exhaust emissions wasdeveloped. A survey of existing international and national standard dieselengine duty cycles was conducted. All were found to be inadequate for testingand certification of engine exhaust emissions from naval diesel powered ships.Naval ship data covering 1 1 ,500 hours of engine operation of four U.S. NavyLSD 41 Class amphibious ships was analyzed to develop a 27 point classoperating profile. A procedure combining ship hull form characteristics, shippropulsion plant parameters, and ship operating profile was detailed to derive an1 1 -Mode duty cycle representative for testing LSD 41 Class propulsion dieselengines. A similar procedure was followed for ship service diesel engines.Comparisons with industry accepted duty cycles were conducted using exhaustemission contour plots for the Colt-Pielstick PC-4B diesel engines. Resultsshowed the 1 1 -Mode LSD 41 Class Duty Cycle best predicted ship propulsionengine emissions compared to the 27 point operating profile propeller curve.The procedure was applied to T-AO 187 Class with similar results. Theapplication of civilian industry standards to measure naval diesel ship propulsionengine exhaust emissions was found to be inadequate. Engine exhaust flowchemistry post turbocharger was investigated using the SANDIA Lab computertool CHEMKIN. Results showed oxidation and reduction reactions withinexhaust gases are quenched in the exhaust stack. Since the exhaust stream inthe stack is unreactive, emission sampling may be performed where mostconvenient. A proposed emission measurement scheme for LSD 41 Class shipswas presented.