ARB Research Seminar

This page updated June 19, 2013

Mobile Off-Road Retrofit SCRT System Demonstration Project

Mark Schmale. P.E., Nitrogen Oxides Systems Development Manager, Johnson Matthey, Malvern, Pennsylvania

July 29, 2010
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


Off-road construction equipment is a significant source of the pollutants carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM) and oxides of nitrogen (NOx) in California. A retrofit Continuously Regenerating Technology (CRT®) and other diesel particulate filter (DPF) technology have been verified by the Air Resources Board (ARB) for significant reduction of CO, HC and PM. These filter technologies are being used on a number of applications throughout the state of California. The focus of this project was to evaluate the combination of a selective catalytic reduction (SCR) system with the CRT® to reduce the NOx from off-road equipment. Previous work has demonstrated that installing a CRT® upstream of a SCR system can enhance the performance of the SCR catalysts along with the reduction of HC, CO and PM. The proposed retrofit SCR system uses NH3 stored in aqueous urea to reduce the NOx in the machine's exhaust. The urea is dosed into the exhaust by an air assisted urea dosing pump. The system is very similar to a retrofit system currently being considered by ARB for verification for use in on-road applications. This paper will outline the process of equipping two pieces of off-road equipment operated by the Los Angeles Sanitation Department with the retrofit SCRT® system. Data will be presented that demonstrates the performance of the system along with a description of the challenges unique to adapting this technology to off-road equipment.

Speaker Biography

Mark Schmale, P.E. - Senior Development Engineer
Mr. Schmale has been with the Johnson Matthey (JM) retrofit development group since August of 2008. Prior to joining JM, Mr. Schmale worked at International Truck and Engine Company and Cummins Engine Company. Mr. Schmale has a BS in Mechanical Engineering from Virginia Tech and a MS in Engineering from Purdue University.

Johnson Matthey is a speciality chemicals company focused on its core skills in catalysis, precious metals, fine chemicals, and process technology.

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