Solutions - Four-Stroke Engines
Overview
The main competitor to the two-cycle spark ignition engine is the older, four-stroke engine, commonly called the Otto Cycle engine.
Major snowmobile manufacturers have begun to introduce new machines powered by four-stroke engines. This appears to be the primary approach to retaining snowmobile access to Yellowstone National Park. The technology for meeting any imaginable requirements for emissions or noise appears easily in hand with conventional, four-stroke engines. Such machines have already been placed in park settings, with plans to expand their use before further restrictions are imposed.
Competing engine technologies include the conventional, piston-type four-stroke Otto engine, and a rotor engine, the Wankel.
The Wankel rotary engine has been employed in vehicles that typically have been powered by two-stroke engines, including about 15,000 engines produced by the Outboard Marine Corporation (OMC).
But the technology has presented several difficulties, including wear and sealing issues. It has also shown lower fuel economy and higher emissions in automotive engines. OMC, which had licensed Wankel patents in the United States and spent considerable effort developing the technology, has filed for bankruptcy. Freedom Motors acquired all of the intellectual property assets for the Wankel, which has developed additional technology for improving emission characteristics of the engine.
Selected Links
Learn More About Four-Stroke Engines
By spring 2002, all four major snowmobile manufacturers, and smaller companies such as Three R Industries (Trail Roamer) and Redline, began touting "environmentally friendly" snow machines powered by four-stroke engines. By July 2002, DEQ teamed up with the National Park Service, and others to evaluate Acrtic Cat and Polaris 4-stoke snowmobiles reported in Laboratory Testing of Snowmobile Engines. Some of the smaller companies are no longer in business. Check the links below for news articles and company announcements about these four-stroke snowmobiles:
- Arctic Cat
- Tahoe.com reports that tests on a four-stroke engine manufactured by Arctic Cat have produced promising results in an article by Emily Aughinbaugh of World News Service titled Industry touts cleaner engines.
- Snowmobile World.com writes about the same snowmobile in an undated article titled Arctic Cat Enters New Era of Cleaner, Quieter Snowmobiles – Fifty Environmentally Friendly Snowmobiles Going to Yellowstone National Park.
- Polaris
- The world's largest snowmobile manufacturer claims it has designed a more environmentally friendly snowmobile. Snowmobile World.com reports about the snowmobile in an article titled Polaris Industries Unveils Cleaner, Quieter Four-Stroke Snowmobile.
