The last major bastion of the two-stroke engine appears to be in snowmobiles. Thanks to liquid cooling, electronic controls, fuel injection, sophisticated combustion techniques, and variable-exhaust-port technology, the latest avalanche of two-stroke “sled” powerplants aims to comply with the new U.S. EPA Phase 3 emissions regulations slated for the 2012 model year.
Can the two-strokes, with their impressive specific output, high power-to-mass ratio, and package benefits, hold their own against the four-stroke assault?
Electromagnetic injectors mount vertically on the liquid-cooled 800R twin’s cylinder head. In this cutaway view, note the internal coolant passages; the engine circulates fuel to help cool the injector.
Bombardier Recreational Products (BRP) engineers believe they can. BRP’s evidence is the recently unveiled Rotax E-TEC 800R, newly equipped with direct fuel injection (DI) and slated for 2011 Ski-Doo sleds. (BRP owns Rotax, Ski-Doo, as well as Evinrude marine engines and Sea-Doo watercraft.)
To read the rest of this article please go to – http://www.sae.org/mags/AEI/POWER/8157
