Customers are demanding propulsion systems giving as much as possible riding pleasure while still considering strict environmental regulations. BRP-Powertrain developed an engine for their snowmobile brand Ski-Doo fulfilling both needs. The Inline two cylinder four stroke engine using a multi port fuel injection system significantly contributes to an impressive and up to now second-to-none cruising range of 29 miles per gallon.
With 42 kW at 7250 1/min the performance target was achieved. Excellent combustion stability allows Lambda values of 1.1 and higher in part load. This also contributes to the good fuel efficiency.
The geometrical layout of the engine was driven by vehicle boundaries. All the power pack components had to be installed using a minimum of space. A low center of gravity was an absolute need for stable riding properties of the snowmobile. Therefore the crankshaft was put as low as possible which left no room for an oil pan underneath the engine. This led to a dry sump oil circuit evacuating the crank chamber by a pump to an integrated oil tank. The rear engine contour is forming one wall of the tank, which is a unique feature. This detail shows the high grade of integration of components. The perfect cooperation of both frame designers and engine developers was supported by using a digital mock up at each stage of the development process.
Additional customer value is given by the possibility to start the engine down to minus 40 degree Celsius, maintenance free valve tappets and a nearly negligible oil consumption which was achieved by an optimized cylinder honing process.