To meet recently proposed exhaust emission standards, the Environmental Protection Agency (EPA) says manufacturers for the first time will use catalytic converters in many types of lawn equipment, garden equipment and small watercraft.
While using catalytic converters is one way to meet exhaust emission standards for nonroad spark-ignition (SI) engines rated below 25 horsepower, it is not the only way. Instead of using exhaust catalysts, Kohler will use another form of after-treatment, its own unique Exhaust Induction System for an interim solution. Subaru Robin's solution includes an efficient combustion chamber and redesigned piston rings to reduce oil consumption. Kohler's final solution also will include an efficient combustion chamber and redesigned piston rings.
Current EPA regulations for small engines focus on reducing hydrocarbons, which can be done by controlling engine oil consumption through tight engine manufacturing standards, says Richard Koehl, Kohler director of marketing and quality.
"The proposed EPA guidelines are much more stringent than the old ones," Koehl says. "You must have some form of after treatment or better manufacturing technology to achieve the levels they're looking for."
Specifically, the proposed standards include hydrocarbon and nitrogen oxides exhaust emission standards of 10 g/kW-hr for Class I engines starting in the 2012 model year and 8 g/kW-hr for Class II engines starting in the 2011 model year. EPA is not proposing new exhaust emission standards for hand-held equipment. For spark-ignition engines used in marine generators, EPA is proposing a more stringent Phase 3 CO emission standard of 5 g/kW-hr, and this would apply equally to all engine sizes subject to the Small SI (spark-ignition) standards.
When the proposed standards are fully implemented, EPA says the new engines' exhaust will have 35 percent less hydrocarbon and nitrogen oxides emissions.
"Regulations that have applied to automobiles are being applied to small, general-purpose industrial engines," says Brad Murphy, Subaru Robin vice president of sales and marketing. "If you add regulations to a $30,000 car, you can maybe raise the price $200 or $300, a percent of the overall vehicle value that's not that much. But you add new technology to small engines and you have to be careful, you could increase the value of the product sold to an OEM significantly. The challenge engine manufacturers face is how to meet the regulations and lower emissions while keeping the cost reasonable so people can afford the product."
Newly proposed EPA requirements will affect most of the million-plus engines Kohler produces annually for consumer lawn and garden, commercial turf, industrial/construction and rental applications. Other engines produced by the company are over 25 horsepower and subject to different EPA requirements.
Kohler's strategy to exceed recently proposed exhaust emissions regulations for small engines involves various technologies.
Essential to these is Kohler's patent-pending Exhaust Induction System, which will be added to Kohler's Courage family of engines first for the California market. The system introduces a precise measure of oxygen into the exhaust and creates chemical reactions similar to those that take place in a catalytic converter to reduce harmful pollutants.
"Basically a new air stream is introduced into the exhaust section," Koehl explains. "You then have an equivalent chemical reaction - but without the heat portion required of the catalyst. Instead, air is burned downstream of the exhaust poured on the engine."
Continuous oxidization of carbon monoxide and hydrocarbons, the main contributors to smog, achieves the same exhaust emission reduction levels as using an after-treatment catalyst, Koehl says.
But Kohler's technological improvements will not stop there. Koehl says the company will continue developing its technology and processes to manufacture an engine that requires no after-treatment for exhaust. By 2011, when the EPA ruling that impacts most Kohler engines goes into effect, he says Kohler will have a solution with "exhaust-out emissions," with no additional parts required.