California Air Resources Board

Principal Investigator/Author: Tom Durbin

Contractor: University of California, Riverside

Contract Number: 17RD013

Project Status: Active

Relevant CARB Programs: Mobile source Emissions Inventory, Mobile Source Emissions Research Program, Potential Amendments to Off-Road New Diesel Engine Emission Standards: Tier 5 Criteria Pollutants and CO2 Standards, FARMER Program

Topic Areas: Air Pollution Exposure, Heavy-Duty Vehicles, Heavy-Duty Vehicle Research, State Implementation Plans (SIPs), Particulate Matter (PM), PM2.5

Research Summary: 

Construction equipment represents one of the most significant sources of NOx emissions in the heavy-duty off-road sector. The focus of this study is to evaluate the operational patterns and activity of off-road equipment during typical operation. The current study expanded on previous studies by focusing on the activity data collection that covered a comprehensive array of equipment types and engine power ratings for construction equipment, and which is now being extended to the collection of agricultural equipment. For this study, activity monitoring was done for 54 pieces of construction equipment, with data analysis completed to date on 35 pieces of equipment, representing a range of 9 different equipment types.  The data were analyzed to provide summary statistics, including operation hours, idle %, number of engine starts per day, power/work output, and fuel use for each vocational use. The data was also compared against existing engine certification cycles to assess their representativeness and the suitability of these cycles in evaluating the effectiveness of NOx control by SCR for different equipment types. Preliminary duty cycles were also developed based on the activity data collected and analyzed to date. Additional data monitoring and analysis are planned to bring this total to 100 pieces of equipment for up to 10 different equipment categories. This report will be updated to incorporate the results and analysis from the additional pieces of equipment once this additional work has been completed. As algorithms and an analysis framework have been developed, it is anticipated that the revised analysis can be completed quickly once the additional data is on hand.

Keywords: off-road, diesel engines, NOx, heavy-duty vehicles, construction equipment, activity data, data logger, emission, tractor