Cranking procedure for a four-stroke internal combustion engine with a crankshaft mounted electric turning machine

A method for starting an internal combustion engine, the engine having:

• one or more cylinders, each of the one or more cylinders having at least one intake valve and at least one exhaust valve,
• at least one cylinder head connected to the one or more cylinders,
• one or more pistons, each piston being disposed in a corresponding one of each of the one or more cylinders,
• one or more variable volume combustion chambers, each combustion chamber being defined between a corresponding one of the one more cylinders, the corresponding piston and the at least one cylinder head, and
• a crankshaft operatively connected to each of the one or more pistons,
• the method comprising:
• a) selectively rotating the crankshaft, using an electric turning machine operatively connected to the crankshaft, in a first direction toward a reversal point close to a local maximum of a drag torque of the internal combustion engine without rotating the crankshaft beyond the reversal point, the drag torque of the internal combustion engine varying according to opening and closing of the intake and exhaust valves, a predetermined level of current delivered to the electric turning machine being based at least in part on the drag torque of the internal combustion engine;
• b) following operation a), selectively rotating the crankshaft, using the electric turning machine, in a second direction opposite from the first direction;
• and
• c) following operation b), selectively injecting fuel in one of the one or more combustion chambers in which the corresponding piston first reaches a top dead center (TDC) position and selectively igniting the fuel in the one of the one or more combustion chambers.