The Author

Tim Johnson is Director – Emerging Regulations and Technologies for Corning Environmental Technologies, Corning Incorporated. Dr Johnson is responsible for tracking emerging mobile emissions regulations and technologies, and helps develop strategic positioning via new products. He has been with Corning for twenty years, with ten years in the current position. He frequently speaks on diesel emission control technology and trends. In that regard, he received the 2007 Lloyd L. Withrow Distinguished Speaker Award from the SAE. Dr Johnson is a member of the U.S. Environmental Protection Agency (EPA) Clean Air Act Advisory Committee, and the EPA Mobile Sources Technical Review Subcommittee. He is also a member of the Northeast States Center for a Clean Air Future (NESCCAF/NESCAUM) board of directors, and he is on the Board of Advisors for the Center of Environmental Research and Technology at the University of California, Riverside. He is also Co-Chairman of the Diesel Emission Control Committee at the Manufacturers of Emission Controls Association (MECA). He was most recently the co-chair for the U.S. EPA's Advisory Working Group on Clean Diesel and Retrofit. He also served on the U.S. EPA Clean Diesel Independent Review Panel, and California Air Resources Board International Diesel Retrofit Advisory Committee. Finally, he recently edited the book, “Diesel Particulate Filter Technology”, published by the SAE. Dr Johnson earned his BS and MS Engineering Degrees from the University of Minnesota in 1978 and 1979 respectively, and his Doctor of Science from the Massachusetts Institute of Technology in 1987.

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Diesel Engine Emissions and Their Control

Tim Johnson

Corning Environmental Technologies, Corning Incorporated, HP-CB-2-4, Corning, NY 14831, U.S.A.;

Platinum Metals Review

Volume 52 Issue 1 January 2008 Pages 23-37
DOI 10.1595/147106708X248750

Article Synopsis

This review covers recent developments in regulations to limit diesel emissions, engine technology, and remediation of nitrogen oxides (NOx) and particulate matter (PM). The geographical focus of regulatory development is now the European Union (EU), where Euro V and Euro VI regulations for light-duty engines have been finalised for implementation in 2009 and 2014, respectively. The regulations are much more loosely drawn than those for the U.S., but options exist for adapting European vehicles to the U.S. market. Europe is just beginning to address heavy-duty regulations for 2013 and beyond. Engine technology is making very impressive progress, with clean combustion strategies in active development, mainly for U.S. light-duty application. Work with heavy-duty research engines is more focused on traditional approaches, and will provide numerous engine/aftertreatment options for complying with the stringent U.S. 2010 regulations. NOx control is focusing on selective catalytic reduction (SCR) for diverse applications. Zeolite catalysts will be the mainstay of this technology for Japan and the U.S., and perhaps even for some Euro V-compliant applications. The emphases are on low-temperature operation, secondary emissions and system optimisation. Lean NOx traps (LNTs) are effective up to about 60 to 70% deNOx efficiency, and are being considered for light-duty applications. There is growing interest in supplementing LNT performance with integrated SCR, which utilises ammonia generated in the LNT during rich regenerations. Diesel particulate filter (DPF) technology is at a stage of optimisation and cost reduction. Very sophisticated management strategies are being utilised, which open up options for the use of new filter materials and alternative system architectures. Issues with secondary emissions are emerging and are being addressed.

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