Engine manufacturers sign statement of principles covering small engines

Diesel Progress North American Edition, Feb, 1997 by Mike Brezonick

"The statement is a truly win/win situation for society and for engine manufacturers, who welcome this cooperative approach," said EMA Executive Director Glenn Keller. "Since the SOP establishes in advance the emission-reduction targets we have to meet, the small engine industry can feel confident in investing the millions of dollars in research and development programs and tooling needed to produce these low emitting engines."

The agreement, which was signed by several of the giants of the small engine industry in North America, as well as several transplants, continues a record of cooperation between EPA and engine manufacturers. In 1995, for the first time, industry and regulatory agencies cooperated on a similar agreement for truck and bus engines. And last September, another agreement was signed covering nonroad diesel engines (see November 1996, Diesel Progress Engines & Drives).

The latest SOP calls for engine manufacturers to reduce smog-forming hydrocarbons (HC) and oxides of nitrogen (N[O.sub.x]) emissions in-use up to 75 percent from unregulated levels (see chart).

To achieve these lower emissions, the SOP requires larger Class II engines used in products such as consumer ride-on equipment to feature a more advanced overhead valve (OHV) design or its equivalent by the year 2005. In the interim, the SOP calls for comparably clean and durable technology to be adopted for 50 percent of Class II engines by 2001. Currently, it is estimated that approximately one-third of Class II engines manufactured in the U.S. utilize OHV technology.

Engines for the largest-selling equipment, such as the typical walk-behind lawnmower that consumers purchase by the millions, will still be able to employ traditional side-valve engine designs, but with enhanced emissions control [TABULAR DATA OMITTED] technology. These improved engines will also benefit consumers through better fuel economy, less maintenance, and more durability, EMA said.

Other important points of the SOP include:

* A provision agreeing on the importance of an OHV demonstration program for Class I to investigate the potential for increasing penetration of OHV technology in Class I. The program is an experiment to explore the consumer acceptance and feasibility of applying OHV technology to mass production Class 1 engines and would include a series of reports to EPA on the level of success, impediments encountered, market response, costs, emission rates, etc.

* The establishment, by each manufacturer, of a deterioration factor for the 500 and 1000 hour Class 2 useful life categories, based on "good engineering judgment." EPA will also propose, based on available data, optional assigned DFs for the 500 and 1000 hour useful life categories.

* Establishing a method of in-use testing. While not specifically determining test protocols, the SOP calls for the formulation of test procedures, including bench and field testing methods.

Signatories of the SOP are: Briggs and Stratton; Kawasaki Motors; Kohler Co.; Kubota Corp.; Mitsubishi Engine North America; Onan Corp.; Suzuki Motor Corp.; Tecumseh Products Co.; The Toro Co.; and Wis-Con Total Power.

This SOP is significant simply because of the numbers involved. According to figures from Power Systems Research, the Minneapolis, Minn., market research firm, fully 58 percent of the nearly 32.5 million gasoline engines produced in North America in 1996 were 20 hp or smaller. The largest segment, more than 14.5 million, are 5 hp or less and are used in literally hundreds of applications, from lawn & garden equipment to light commercial and industrial machines, including smaller gen-sets, pressure washers, pump sets, etc.

While the SOP sets the agreed-upon targets, it also raises some interesting questions. Making smaller engines more emissions-sensitive has always been complicated in economic terms. In much of the small equipment such engines are used in, the engine is nearly a commodity item - and is priced as such. It is much simpler to add emissions driven technology and components to a larger engine, where a price increase can be more easily accommodated. On a small engine, the addition of emissions equipment can have a dramatic impact on the cost of the engine. The SOP addresses this issue obliquely, calling for a shift to cleaner technology "as quickly as feasible, considering cost and lead time factors."

While OHV technology provides a big step forward for emissions performance, it seems unlikely that all engines, particularly Class I engines, will be able to utilize that technology. And the jury is still out on other emissions control methods.

There is also the human factor to be considered. According to EPA information, evaporative emissions from fuel spillage accounts for almost a third of all HC emissions from small engine powered equipment. EMA and its member companies have conducted public education programs to encourage consumers to fill, operate, and maintain their equipment properly. Under the SOP, additional education programs for spillage reduction will be developed collaboratively with EPA, but there is no telling how effective such programs can be.