Control strategies for heavy-duty diesel engine emissions

Emission standards for heavy-duty diesel engines have become significantly more stringent throughout the last 20 years and continue towards zero emissions levels in the future. Modern direct-injected diesels include well-developed combustion systems that have electronically controlled injection systems and robust turbochargers. These technological advancements enable heavy-duty engine manufacturers to meet emission standards through an adjustment in injection timing by using a small array of sensors in concert with the engine control module (ECM). Standards targeted for 2002 and 2007 will require the inclusion of external devices and associated sensors that will create additional degrees of freedom for the ECM and thus a larger sensor array in comparison to current diesel engines. This article outlines the potential impact of these emission standards on control strategies for heavy-duty engines and the associated sensors under "warmed up" conditions.