What is the Best Methodology for Achieving the "Passive" Diesel Particulate Filter Retrofit of Existing DOT Diesel Engine Fleets While Eliminating Service Delivery Issues and at What Cost/Benefit?

Focus Area

Air Quality


Air Quality






1-2 years

Research Idea Scope

TERI Administrator Note (Feb 2009) Related Research: Diesel Retrofit Technology – An Analysis of the Cost-Effectiveness of Reducing Particulate Matter and Nitrogen Oxides Emissions from Heavy-Duty Nonroad Diesel Engines Through Retrofits; USEPA; May 2007.  Not recommended at present time by 2009 Air Quality Subcommittee. 



With the new federal emissions requirements of 2007 and the impending 2010 requirement, states are passing diesel retrofit laws to address the millions of existing diesel engines currently in use. There are a number of strategies that can be employed to comply with these well intended laws but some technologies are not practical as they may impede delivery of critical public service. The new 2007 trucks employ a “passive” emissions treatment technology that is specifically designed by the truck manufacturer to minimize service delivery issues. “Passive” meaning fully automated on board regeneration of the Diesel Particulate Filter State DOT fleets can be negatively impacted by increased fleet downtime if these systems are “active” and require off board regeneration or if the selected technology fails to perform due to the duty cycle and causes damage.  In 2010 these systems may need to be modified again to include “SCR” technology which is an on board Urea treatment system. This technology will present further challenges both as a new technology and if required in diesel retrofit laws.




A literature search of TRIS online (http://ntl.bts.gov/tris) and the Research in Progress database (http://rip.trb.org/search) revealed no similar research.




Determine “applicability” of diesel retrofit systems for installation on state DOT diesel engine fleets. “Applicability” meaning not only is it available and approved by USEPA or CARB but will the technology perform “passively” in specific duty cycles and can it be realistically engineered onto existing fleet vehicles and at what estimated cost. A cost benefit of retrofit costs versus replacement, including an associated cost for fleet downtime and loss or reduction of public services. What will be the costs associated with “SCR” technology including infrastructure costs to comply with the 2010 federal emissions requirement. Is “SCR” technology “applicable” as defined previously in this section for the retrofit of diesel engines in DOT fleets after 2010.

Suggested By

TRB Research Needs Database, AHD60, Maintenance Equipment