Diesel Engine 2-Stroke Breathing for Aftertreatment Warm-Up

Abstract

Since the introduction of diesel urea SCR technology, aftertreatment thermal management has become critical for maintaining SCR catalyst light-off and thereby low cumulative cycle NOx emissions. A novel diesel engine aftertreatment thermal management strategy is proposed which utilizes a 2-stroke breathing variable value actuation strategy to increase the mass flow rate of exhaust gas. Experiments showed that when emissions are constrained to the same level as a state-of-the-art thermal management strategy, 2SB does not increase heat transfer to aftertreatment. However, if constraints are allowed to flex, temperatures comparable to a state-of-the-art thermal management calibration could be achieved with a 1.75× exhaust mass flow rate, potentially helping heat the SCR catalyst in a cold-start scenario.

A numerical study of piston bowl geometry and diesel injection timing in a heavy-duty diesel/syngas RCCI engine

“…1–3 Consequently, governments encourage automotive industry to design, and build fuel-efficient ICEs by low, or zero carbon emissions. 4 Diesel engines are more widely used in the industry than gasoline spark-ignition engines due to their effective properties such as lower fuel consumption and less CO / C O 2 emissions. 5 However, the combustion process of heavy diesel fuels leads to the formation of hot regions with a high equivalence ratio inside the combustion chamber which causes high cylinder-out NOx and PM emissions.…”