Method and system for starting an internal combustion engine

1. A snowmobile comprising:

a frame;

an engine connected to the frame, the engine comprising;

a crankshaft;

a motor-generator operatively connected to 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 crankshaft;

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 the crankshaft;

a power source electrically connected to the motor-generator;

a control unit electrically connected to the power source;

a temperature sensor communicating with the control unit; and

a start switch communicating with the control unit,

in response to the engine being stopped and the start switch being actuated, the control unit being configured to:

obtain a temperature sensed by the temperature sensor;

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

in response to the temperature being below the predetermined temperature, prohibit starting of the engine using the motor-generator.

2. The snowmobile of claim 1 , wherein, in response to the engine being stopped, the start switch being actuated, and the temperature sensed by the temperature sensor being below the predetermined temperature, the control unit is configured to:

in response to the recoil starter being operated, initiate an engine control procedure associated with a use of the recoil starter in order to start the engine using the recoil starter.

3. The snowmobile of claim 1 , wherein, in response to the engine being stopped, the start switch being actuated, and the temperature sensed by the temperature sensor being above the predetermined temperature, the control unit is configured to:

determine how much time has elapsed since the engine was last stopped;

in response to the time being less than a predetermined time, start the engine using the motor-generator; and

in response to the time being more than the predetermined time, prohibit starting of the engine using the motor-generator.

4. The snowmobile of claim 1 , wherein the temperature sensor is an engine temperature sensor configured for sensing a temperature of the engine.

5. The snowmobile of claim 4 , wherein the temperature sensor is configured to sense at least one of:

a temperature of a crankcase of the engine;

a temperature of a cylinder block of the engine;

a temperature of a cylinder head of the engine; and

a temperature of a coolant of the engine.

6. The snowmobile of claim 1 , further comprising a display communicating with the control unit; and

wherein, in response to the engine being stopped, the start switch being actuated, and the temperature sensed by the temperature sensor being below the predetermined temperature, the control unit is configured to:

cause the display to display an indication that the engine is to be started using the recoil starter.

7. The snowmobile of claim 1 , wherein:

the motor-generator is operatively connected to a first end of the crankshaft; and

the recoil starter is selectively operatively connected to the first end of the crankshaft.

8. The snowmobile of claim 7 , wherein the drive pulley of the CVT is operatively connected to a second end of the crankshaft, the second end of the crankshaft being opposite the first end of the crankshaft.

9. The snowmobile of claim 1 , wherein the engine further comprises:

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,

the crankshaft being operatively connected to the first and second pistons; and

a crankcase housing at least a portion of the crankshaft.

10. The snowmobile of claim 9 , further comprising:

a crankshaft position sensor configured for sensing a position of the crankshaft, the crankshaft position sensor communicating with the control unit; and

first and second spark plugs selectively igniting fuel in the first and second variable volume chambers respectively;

wherein, in response to the engine being stopped, the start switch being actuated, and the temperature sensed by the temperature sensor being above the predetermined temperature, the control unit is configured to:

supply power from the power source to the first and second spark plugs based at least in part on the position of the crankshaft.