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ガソリンエンジン新技術資料 NMMA
* New Marine Technologies
* Sound
New Marine Technologies
Marine engine manufacturers are continuing to pursue development of new technologies that will enable them to maintain their competitive edge in global markets. They work to refine technologies and designs that deliver comparable or improved engine performance over current products.
The recent development of low-emission technologies did not occur by accident. In fact, marine engine manufacturers have been evaluating low-emission designs and technologies for decades. Until the 1990s, however, the advanced engineering and electronic technology required to facilitate bringing these new and innovative engine technologies to the market was unavailable.
After the Clean Air Act Amendments of 1990, Congress, realizing that emissions reductions for on-road engines had nearly reached the point of diminishing returns, required the Environmental Protection Agency (EPA) to inventory non-road engines and determine if new regulations were both technologically and economically feasible.
Non-road sources include lawn and garden equipment, snowmobiles, marine engines and potentially every other engine that is not an automobile. The EPA determined that all averaged non-road sources in the United States equate to 10 percent of the total HC emissions. When the EPA inventoried all the recreational marine engines in the United States, including diesel, two-stroke and four-stroke engines, it found that all the recreational marine engines put together contributed 30 percent of the average total non-road HC emissions. This amounts to three percent of total HC emissions in the United States, or less than one-tenth of the HC emissions attributed to automobiles. (Automobiles are still responsible for 33 percent of HC emissions.)
In cooperation with the marine industry, the EPA developed a new regulation that was established in August 1996. This regulation covers outboard engines and gasoline marine engines used in personal watercraft and jet boat applications. The regulation required a reduction in HC emissions beginning in 1998 to be phased in over the next eight years, ultimately achieving a 75 percent reduction by 2006. This timeline allows for the spreading out of development costs for technologies that did not yet exist.
Since that time, marine engine manufacturers have pursued a variety of technologies designed to enhance their engine's performance, improve fuel economy, reduce smoke and noise, as well as meet regulatory mandates, yet keep their products competitively priced in the market. Many of these technological breakthroughs have become benchmark standards in the marine industry. In fact, there are low-emission engines on the market today that already meet the emission reduction requirements for 2006, a significant achievement considering it took the automobile industry over 25 years to achieve approximately a 90 percent reduction in emissions.
Manufacturers are relying on three basic technologies to achieve compliance with the regulatory standards direct-injection for two-stroke engine designs, catalytic converters and high-performance four-stroke technology. Even though the EPA emission standards have been in effect for less than two years, marine engine manufacturers have already introduced a range of low-emission technology engines to the market.
