Diesel Initiative for Retrofit Technology

D.I.R.T - Completed March 2006

In an effort to improve air quality in the metro Denver region, the Regional Air Quality Council (RAQC) partnered with Instrument Sales and Service, Inc. (ISS) to install emissions reduction equipment on off-road diesel fleet vehicles.  This demonstration project, the Diesel Initiative for Retrofit Technology (D.I.R.T.), utilized simple, innovative emissions reduction technology to reduce visible exhaust and other pollutants from off-road vehicles.  Diesel oxidation catalysts (DOCs) and closed crankcase filtration units (Spiracles) were installed in tandem to deliver maximum emission reduction benefits from retrofitted vehicles. 

 

Technology 

Diesel oxidation catalysts replace the muffler and are installed in the exhaust system.  The ceramic core catalyst is coated with precious metals that trigger chemical reactions which breakdown pollutants – carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) – into harmless gases when engine exhaust passes through the system.

The Spiracles are closed crankcase filtration systems that completely eliminate all of the emissions coming from the crankcase which equates to 25 percent of total vehicle emissions.  The combination of DOCs and Spiracles are estimated to reduce HC emissions by 40 percent, PM emissions up to 32 percent, and CO emissions up to 34 percent.      

 

Program Achievements

The Regional Air Quality Council partnered with Commerce City to install DOC/Spiracle retrofit combinations on four of the City's tandem snow plow-dump trucks.  The retrofits were successfully completed in March 2006.  Click on the following link to view the press release Commerce City Press Release.  The RAQC also partnered with a private off-road company, Brannen Sand and Gravel.  DOC/Spiracle combinations were installed on multiple off-road vehicles.  All partners received maximum emissions reductions benefits from equipment installations.  Program details including successes and challenges have been summarized in the Final Report, click on the following link to view DIRT Final Report.