Small Engine Emissions Research

Emissions research on small engines is an important part of the total Southwest Research Institute (SwRI) program in pollutant identification and control. As with all our emissions work, the major goal is to help industry bring advanced, environmentally friendly engines, control systems, fuels, and lubricants to the market and to work to keep them there.

The Institute combines extensive experience, sophisticated facilities, and innovative ideas to meet the goals of clients in both industry and government.

Institute test stands for small engine emissions research handle engines of less than 1 hp to more than 100 hp. A high-speed, low-inertia dynamometer absorbs 20 hp at speeds up to 18,000 rpm in the horizontal shaft configuration. Air and fuel flow measurements are available, and whole exhaust is diluted to measure particulates using a 90 mm filter system. SwRI recently added continuous and bag dilute sampling and cyclic operations.

Experience

The Institute has been involved in emissions research for more than 20 years, including several landmark studies of small engines for the Environmental Protection Agency. Keeping pace with constantly improving measurement techniques, SwRI applies its extensive experience to emissions research programs involving outboard motors and engines used in power mowers, chain saws, weed trimmers, snowmobiles, motorcycles, and personal watercraft. The Institute has more than four decades of related experience in oil certification, durability testing, and test stand design and fabrication.

SwRI uses industry standard continuous raw exhaust instrumentation for characterization, deterioration factor, and control technology research. Supporting data are collected with charts and data loggers. Gas standards and calibrations meet criteria established by the National Institute of Standards and Technology.

A low-inertia, water-brake dynamometer, capable of absorbing 100 hp at 14,000 rpm, tests snowmobile and personal watercraft engines.

Facilities

The SwRI Department of Emissions Research maintains a dedicated test cell exclusively for small engine emissions research. Equipped with a 20 hp vertical/horizontal shaft dynamometer, a 1 hp all-position dynamometer, and 30, 50, 100, and 175 hp horizontal shaft dynamometer, the cell is instrumented to measure raw exhaust gaseous emissions. Two whole-exhaust dilution and sampling systems are installed to measure particulates. Torque and speed can be controlled manually or automatically. The Institute tests according to a variety of operational and measurement sequences, including the SAE J1088 procedure, applicable ISO 8178 cycles, and custom cycles. Analysis for the complete range of unregulated pollutants and detailed hydrocarbon speciation are available.

The Department of Emissions Research small utility engine test cell contains six dynamometers, dilute and direct gas analyzers, two particulate dilution tunnels with sampling systems, and testing coordination controls.

Ideas

Both the Environmental Protection Agency and the California Air Resources Board are developing emission regulations for several categories of previously unregulated nonroad and off-highway equipment. The Institute offers a variety of services to help manufacturers meet these new regulations, including emissions certification and compliance programs. Research programs can determine baseline engine emissions and evaluate potential emission-reducing technologies. Manufacturers, suppliers, and users come to SwRI for fresh ideas for making small engines more compatible with the environment while maintaining engine life, reliability, performance, and costs.

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