Crankcase Blowby Characterization From an EMD 16-645-E Locomotive Diesel Engine

This paper documents results from an experimental study performed to determine the contribution of crankcase blowby to exhaust particulate matter (PM) emissions from an EMD 16-645-E, roots-blown, 1,500 kW, diesel locomotive engine. The EMD 16-645-E roots-blown engine is equipped with a closed crankcase system, where blowby is routed through an inertial separator and then into the intake air system, downstream of the intake air filters, but upstream of the roots blowers. This paper describes the system used to quantify the blowby flow rate, the blowby PM concentration (mg/m³), and the PM mass flow rate (g/hr) that is returned to the engine intake air. Since crankcase blowby is drawn from the crankcase and into the intake air due to the vacuum created by the intake air filter restriction, a series of experiments were also performed to document blowby flow rates as a function of intake air filter restriction. Blowby PM measurements were also taken upstream and downstream of the inertial separator that is used to remove some of the larger blowby aerosol particles. These data were then used to calculate the filtration efficiency of the inertial blowby separator. The crankcase blowby PM emissions are compared to the engine-out exhaust PM emissions. Results from this study indicate that for the EMD 16-645-E locomotive diesel engine tested, crankcase blowby represents less than 2 percent of the total exhaust PM emissions.