COMBUSTION SYSTEM STRATEGY TO MEET TIER4 FINAL EMISSION REGULATIONS IN A LOCOMOTIVE APPLICATION FOR A LARGE BORE HIGH SPEED DIESEL ENGINE

摘要

The combustion system of a large bore four stroke diesel engine was developed using the Analysis Led Design (ALD) process. A combustion strategy of particulate matter (PM) control in-cylinder and oxides of nitrogen (NO_x) controlled through urea based selective catalytic reduction (SCR) of the engine exhaust, was adopted. Combustion analysis tools and single cylinder engine (SCE) tests were used to determine key combustion parameters like in-cylinder swirl, fuel injector configuration and, combustion chamber design to meet the EPA Tier4 final emission regulations at the different notch settings of the locomotive test cycle. Experimental validation of the ALD recommended hardware was accomplished on the SCE and the best combination was selected. Engine out PM and NO_x target compliance was demonstrated on the multi cylinder diesel engine (MCE) over the composite locomotive notch cycle. Selective fuel Injector strategy was applied to control excessive unburned hydrocarbons (UHC) at low load engine operating conditions within the locomotive notch cycle.