Method and system for starting an internal combustion engine

1. A method for starting an internal combustion engine of a snowmobile, 5 the engine comprising:

first and second cylinders;

at least one cylinder head connected to the first and second cylinders;

a first piston disposed in the first cylinder,

the first cylinder, the at least one cylinder head and the first piston defining a first variable volume combustion chamber therebetween;

a first fuel injector for injecting fuel in the first variable volume combustion chamber;

a second piston disposed in the second cylinder,

the second cylinder, the at least one cylinder head and the second piston defining a second variable volume combustion chamber therebetween;

a second fuel injector for injecting fuel in the second variable volume combustion chamber;

a crankshaft operatively connected to the first and second pistons;

a crankcase housing at least a portion of the crankshaft;

a motor-generator operatively connected to a first end of the crankshaft, the motor-generator being operable in motor mode to rotate the crankshaft and in generator mode to generate electricity; and

a recoil starter selectively operatively connected to the first end of the crankshaft;

the snowmobile comprising:

a frame;

the engine connected to the frame;

a drive track operatively connected to the frame;

at least one ski operatively connected to the frame;

a continuously variable transmission (CVT) operatively connecting the engine to the drive track, the CVT having a drive pulley and a driven pulley, the drive pulley being operatively connected to a second end of the crankshaft, the second end of the crankshaft being opposite the first end of the crankshaft; and

a power source electrically connected to the motor-generator, the first injector and the second injector;

the method comprising:

actuating a start switch of the snowmobile;

in response to the start switch being actuated, sensing a temperature;

in response to the sensed temperature being above a predetermined temperature, starting the engine using the motor-generator; and

in response to the sensed temperature being below the predetermined temperature, starting the engine using the recoil starter.

2. The method of claim 1 , further comprising:

sensing a position of the crankshaft using a crankshaft position sensor; and

in response to the sensed temperature being above the predetermined temperature, supplying power from the power source to first and second spark plugs based at least in part on the position of the crankshaft, the first and second spark plugs selectively igniting fuel in the first and second variable volume chambers respectively.

3. The method of claim 2 , wherein the crankshaft position sensor is an absolute position sensor.

4. The method of claim 1 , further comprising, in response to starting the engine using one of the motor-generator and the recoil starter, injecting fuel directly in the first and second variable volume chambers using the first and second fuel injectors.

5. The method of claim 1 , wherein sensing the temperature comprises sensing an engine temperature.

6. The method of claim 5 , wherein sensing the engine temperature comprises sensing a temperature of at least one of:

the crankcase;

a cylinder block of the engine;

the cylinder head; and

an engine coolant.

7. The method of claim 6 , wherein the temperature is the temperature of the engine coolant.

8. The method of claim 1 , further comprising, in response to the sensed temperature being below the predetermined temperature, displaying on a display of the snowmobile an indication that the engine is to be started using the recoil starter.