A method of starting an integrated starter generator drives a starter generator without using a rotor position sensor to start an engine. The method includes the following steps of: (a) applying a first drive current with a first frequency and a first amplitude to drive the starter generator to reversely rotate in a speed open-loop control mode, and acquiring a first load information according to a drive voltage and the first drive current of the starter generator, (b) confirming whether the first load information meets a heavy load condition, (c) stopping reversely rotating the starter generator when the first load information meets the heavy load condition, and (d) forwardly rotating the starter generator to drive the engine to start.

A method for starting an internal combustion engine of a snowmobile is disclosed. The method comprises 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 a motor-generator; and in response to the sensed temperature being below the predetermined temperature, starting the engine using a recoil starter.

A method for starting an internal combustion engine of a snowmobile is disclosed. The method comprises 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 a motor-generator; and in response to the sensed temperature being below the predetermined temperature, starting the engine using a recoil starter.

A method for starting an internal combustion engine of a motor vehicle includes detecting before a direct starting of the internal combustion engine that a piston which is disposed translationally moveably in a start cylinder of the internal combustion engine is in an upper half of, or in a middle of, a stroke of the piston. In response to the detecting, rotating an output shaft of the internal combustion engine in a direction of rotation of the output shaft such that the piston is in a lower half of the stroke of the piston and in an intermediate position. The method further includes rotating the output shaft in a second direction of rotation before and/or during fuel being first directly injected into the start cylinder such that the piston is moved out of the intermediate position in a direction of an upper dead center of the piston.

Embodiments of the present invention provide a controller for a starter motor operable to receive a first input indicative of an engine shutdown being required, a second input indicative of a change-of-mind event having occurred after initiation of engine shutdown and a third input indicative of the engine position. After receipt of the first input the controller is operable to monitor the third input and to determine an expected engine rotation direction indicative of the expected rotation direction of the engine after a predetermined delay. If the expected engine rotation direction is positive and the second input is received then the controller is configured to control the output means to cause the starter motor of the engine to be actuated upon receipt of the second input. If the expected engine rotation direction is negative and the second input is received then the controller is configured to delay controlling the output means to cause the starter motor of the engine to be actuated until a determination is made that the expected rotation direction is positive. Advantageously, the controller calculates the expected engine rotation direction before receipt of the input indicative of the change-of-mind event having occurred, thereby reducing the time required to determine whether or not the starter motor can be actuated.

A method of starting an integrated starter generator drives a starter generator without using a rotor position sensor to start an engine. The method includes the following steps of: (a) applying a first drive current with a first frequency and a first amplitude to drive the starter generator to reversely rotate in a speed open-loop control mode, and acquiring a first load information according to a drive voltage and the first drive current of the starter generator, (b) confirming whether the first load information meets a heavy load condition, (c) stopping reversely rotating the starter generator when the first load information meets the heavy load condition, and (d) forwardly rotating the starter generator to drive the engine to start.

An engine driving apparatus includes an engine, a starter motor, and a starter motor controller. The engine includes a plurality of cylinders. When any one of the plurality of cylinders enters a compression stroke, another one of the cylinders enters an expansion stroke. The starter motor is coupled to a crankshaft of the engine. The starter motor controller is configured to control the starter motor. Before restarting the engine, the starter motor controller performs pre-restart control for adding torque to the crankshaft by using the starter motor to open an exhaust valve of the cylinder in the expansion stroke.

A method and system for controlling a stop rotation position of an engine is described. In one example, the system includes an integrated starter/generator that may be selectively coupled to the engine. The integrated starter/generator may rotate the engine in a first direction (e.g., reverse direction) or a second direction (e.g., a forward direction) in response to a position at which the engine stops rotating following cessation of combustion in the engine.

A method and system for controlling a stop rotation position of an engine is described. In one example, the system includes an integrated starter/generator that may be selectively coupled to the engine. The integrated starter/generator may rotate the engine in a first direction (e.g., reverse direction) or a second direction (e.g., a forward direction) in response to a position at which the engine stops rotating following cessation of combustion in the engine.

An engine drive system comprises a processor and a control module coupled to the processor. The control module receives a signal from a crank sensor system, the signal being indicative of at least one of a speed and load of a crankshaft. Based on the signal received from the crank sensor system, the control module determines whether a load on the crankshaft is greater than a threshold value. Based on the determination, the control module controls an electrical machine coupled to the crankshaft to rotate the electrical machine in one of a forward direction and a reverse direction.