Engine Research

EPA's engine research focuses on developing engines that are simultaneously clean, efficient, and cost effective, and which have high potential to produce real-world benefits.

Clean Diesel Combustion technology is one example of these innovative engine concepts. EPA's testing suggests the potential for a diesel engine design, using innovative air, fuel, and combustion management and conventional particulate matter aftertreatment, to achieve lower NOx levels without the need for NOx aftertreatment. EPA is developing this technology as a potential alternative with other diesel emissions control approaches (e.g., NOx adsorbers, urea selective catalytic reduction (SCR), etc.). Clean Diesel Combustion technology shows the potential to meet NOx levels "engine-out" over the entire engine operating range, to a level required for future diesel emissions standards. EPA has partnered with several automotive and engine manufacturers to evaluate the production feasibility of this technology. Using clean diesel combustion technology in conjunction with the full hydraulic drive is projected to improve fuel economy more than using either technology alone.

• Fact Sheet: Clean Diesel Combustion -- Clean, Efficient, and Cost Effective Technology
• Presentation and speaker's notes: A Path to More Sustainable Transportation presentation includes an update on an EPA diesel combustion technology that meets the 2007 heavy duty standards with engine-out NOx emissions of less than 0.2 gm/BHP/hr without the need for any NOx aftertreatment.
• Presentation on SAE Paper 2004-01-0933: An HCCI Engine Power Plant for a Hybrid Vehicle . This presentation describes work conducted at the National Vehicle and Fuel Emissions Laboratory to explore the potential use of a homogenous charge compression ignition (HCCI) as a power plant for a hybrid vehicle.