Grantee Research Project Results
Final Report: PM 2.5 Emissions Reduction for Two-Stroke Engines
EPA Contract Number: EPD10013Title: PM 2.5 Emissions Reduction for Two-Stroke Engines
Investigators: Annen, Kurt D.
Small Business: Aerodyne Research Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2010 through August 31, 2010
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2010) RFA Text | Recipients Lists
Research Category: SBIR - Air and Climate , Small Business Innovation Research (SBIR)
Description:
A significant source of PM2.5 emissions is small two-stroke engines, which are used in outdoor power equipment such as leaf blowers, chain saws, and string trimmers, as well as larger two-stroke engines used in recreational vehicles such as ATVs, motorcycles, snowmobiles, and marine outboard motors. These engines account for roughly 25 percent of the PM2.5 emissions from the 2002 NONROAD emission inventory. Also, because the operators of these engines are typically very close to the source of the PM2.5 emissions, the health effects will be heightened relative to other PM2.5 sources.
This Phase I SBIR program had as its main goal the demonstration that very significant reductions in PM2.5 emissions from two-stroke engines can be achieved with existing technology. The approach was to modify two-stroke engines to achieve reductions in PM2.5 emissions by a factor of four or more. Several leaf blowers powered by 26 cc two-stroke engines were used in the investigation. The engines were modified and particulate and gaseous emissions from the leaf blowers were measured to assess the reduction in particulate emissions and the change in gaseous emissions. The leaf blower engines also were evaluated for durability and any change in particulate and gaseous emissions over their 50-hour rated life.
Summary/Accomplishments (Outputs/Outcomes):
The Phase I results showed that particulate emissions from two-stroke engines can be reduced by a factor of four or more using our engine modification approach, and that gaseous emissions are essentially unchanged by the engine modification. Detailed real-time measurements of particulate emissions were performed using SMPS (Scanning Mobility Particle Sizing) and AMS (Aerosol Mass Spectrometer) instruments to document the particulate emissions and to determine particulate emission indices for the engines. Reductions in particulate emissions were observed both for engines with standard mufflers and for engines with catalytic mufflers. The engine modification approach was found to have no adverse effect on durability for good-quality two-stroke engines, though it resulted in significantly lower durability for medium- to low-quality small two-stroke engines.Conclusions:
Particulate emissions from two-stroke engines can be reduced by a factor of four or more using our engine modification approach, and reductions are achieved whether or not a catalytic muffler is used for exhaust aftertreatment. Gaseous emissions were essentially unaffected by the engine modification. Although our approach for particulate reduction was found to have an adverse effect on durability for lower quality small two-stroke engines, it had no effect on durability for good quality engines. Because most two-stroke engines larger than the nominal 26 cc size (~1 hp) tested in this project are of good quality or better, our approach for particulate emissions reduction from two-stroke engines is broadly applicable.
Commercialization:
The reduction of particulate emissions from two-stroke engines has very significant widespread benefits for the improvement of air quality and the reduction of adverse health effects, both in the United States and abroad, particularly where two-stroke engines are the dominant power source for small scooters and motorcycles in wide use in urban areas in the Far East. The low cost of implementing this particulate emission reduction technology favors widespread implementation of the technology. Aerodyne's commercialization approach has been focused on patent protection, with the goal of licensing the technology to manufacturers of two-stroke engines and of products using two-stroke engines. The acquisition of additional durability test data on the engine modification approach in a broader range of engines considered in the Phase I program will be important in convincing manufacturers of the attractiveness of the technology, and regulatory agencies of the availability and robustness of the technology.
The particulate emission reduction technology is applicable to two-stroke engines used in a wide range of equipment and vehicles, including handheld outdoor power equipment, recreational vehicles such as ATVs, dirt bikes, snowmobiles, and marine outboard motors, and on-road vehicles such as motorcycles and scooters.
Supplemental Keywords:
small business, SBIR, EPA, emissions standards, two-stroke engines, air pollution, small particle emissions, air quality, emission reduction technology, air quality, PM2.5, fine particulate matterThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.