The prestigious Southwest Research Institute (SwRI) recently published a technical brochure titled "Two-Stroke Engine Technology." Explained within is SwRI's research aimed at solving the problems of exhaust emissions, noise, vibration and harshness, all of which have deterred the automotive use of the "two-stroke" engine.
On the construction side, small-displacement, two-stroke engines are used extensively to power construction tools such as cut-off saws, compactors and breakers. Critics of the engine, though, are hinting at its demise. The two-stroke will have difficulty complying with emissions standards, they say, and advancements in four-stroke-cycle engines will allow the "four-cycle" to take over two-stroke jobs.
CE had occasion recently to visit with two-stroke-engine manufacturers, however, and found them working diligently toward emissions compliance. Potential technology encompasses refinement of the combustion chamber and exhaust-gas scavenging systems, refinement of oiling systems to reduce the quantity of lubrication required in the two-stroke's fuel, and perhaps on the horizon, direct-injection fuel systems (maybe even electronic versions) and catalytic mufflers.