Additionally, it is easily miscible with diesel and gasoline and can be combusted in conventional, unmodified Otto-cycle
Unlike the typical Otto-cycle
engine, it has less power density and low-rpm torque, but higher efficiency.
The next two key milestones came during the 1880s, with the invention by Benz, Daimler and Maybach of the gasoline-fuelled Otto-cycle
internal combustion engine and the patenting of Charles Parsons' steam turbine.
Otto-cycle engines fueled by natural gas are common in cities as the operators of buses and other vehicle fleets try to keep emissions in check.
The company, however, is concentrating on natural gas Otto-cycle engines, including the conversion of diesels to spark ignition, according to its vice president of engineering, Paul Newman.
There are Otto-cycle
and Stirling engines, and there is the form of carbon called "buckminsterfullerene" (bucky-balls), on the short list of examples.
* Amendments to the 2004 HD highway engine emission regulation, published as a proposed rule in October, introduce new heavy-duty emission standards for Otto-cycle
The engine operates on the Atkinson cycle, which provides thermal efficiency as compared to the conventional Otto-cycle
engine, which generally has a higher exhaust gas temperature, and provides a clean burn, which contributes to the California SULEV emissions certification and Tier 2 Bin 3 in other states.
Today, most engineers try to refine the Otto-cycle design to improve on its thermal efficiency.
In the Otto-cycle engine, each piston makes four strokes of virtually equal length during the intake, compression, expansion, and exhaust cycles.
The small SUV runs an Atkinson-cycle variant of the 2.3-liter Duratec 23 four-cylinder engine, which increases efficiency by nearly 4% compared to the standard Otto-cycle
Duratec 23 in the base 2005 Escape.