An engine control device includes an electronic control unit. The electronic control unit is configured to perform a spark discharge with an ignition plug for each cylinder by cutting off energization after elapse of a predetermined period from start of energization to an ignition coil for each cylinder of the engine, to stop the spark discharge caused by the ignition plug for each cylinder after supply of fuel to the engine is stopped when operation of the engine is stopped, and to control an ignition plug so as to stop the spark discharge caused by the ignition plug from a cylinder after a rotation speed of a crankshaft decreases gradually and the rotation speed of the crankshaft reaches a preset threshold value or less, after the stop of the supply of fuel to the engine.

An engine control device includes an electronic control unit. The electronic control unit is configured to perform a spark discharge with an ignition plug for each cylinder by cutting off energization after elapse of a predetermined period from start of energization to an ignition coil for each cylinder of the engine, to stop the spark discharge caused by the ignition plug for each cylinder after supply of fuel to the engine is stopped when operation of the engine is stopped, and to control an ignition plug so as to stop the spark discharge caused by the ignition plug from a cylinder after a rotation speed of a crankshaft decreases gradually and the rotation speed of the crankshaft reaches a preset threshold value or less, after the stop of the supply of fuel to the engine.

A method for updating a crank position tooth number in a crank position sensor signal obtained from a crankshaft position sensor of an engine of a vehicle includes: calculating, in platform software of an engine control unit (ECU), a pulse width of a crank position sensor signal, determining, in the platform software of the ECU, a forward rotation and a reverse rotation of an engine, and updating, in the platform software of the ECU, the crank position tooth number.

A vehicle has a frame, a front suspension assembly, a pair of skis, an endless drive track, and an internal combustion engine. The engine has: a motor-generator having a rotor and a stator, the motor-generator being operable in motor mode and in generator mode; a recoil starter operable to rotate a crankshaft of the engine via the rotor in a same direction as does the motor-generator in generator mode; at least one sensor adapted for sensing at least one engine parameter; and an engine control unit (ECU) receiving a signal from the at least one sensor, the ECU controlling a rotation of the crankshaft by one of the motor-generator and the recoil starter based on the signal. The vehicle also has a display for displaying a message when the crankshaft is to be rotated by the recoil starter.

An engine control apparatus predicts the speed of an engine in a normal rotation range as a function of a loss energy in an engine rotation pulsating period and also predicts the speed of the engine in a reverse rotation range as a function of a pumping loss component and a loss energy which is derived by reversing the sign of a value of a friction component that is a portion of the loss energy in the normal rotation range and arises from mechanical friction to which the piston is subjected during stroke thereof. The pumping loss component is an energy loss occurring in the intake stroke of the engine. This calculation enhances the accuracy in predicting a future engine speed between start of a drop in speed of the engine resulting from stop of combustion of fuel and stop of rotation of the engine.

A control device sets reverse rotation period as a cranking prohibition period, and when a start request of an engine is generated during reverse rotation period, cranking is started by driving either or both of the first starter and the second starter when it is detected that a crankshaft is shifted from reverse rotation to forward rotation based on an information of a rotation angle sensor. As a result, the delay from generation of the start request of the engine until cranking is started can be reduced, so that the starting time of the engine can be shortened.

A system for starting an engine of a vehicle has a fuel injector injecting fuel into a closed intake port to form an air fuel mixture. The system also includes an actuator rotating a crankshaft in a first direction to open the intake port by moving a piston within a cylinder coupled to the crankshaft. A combustion chamber defines between the cylinder and the port receiving the air fuel mixture through the intake port. The actuator rotates the crankshaft in a second direction to close the intake port. A spark plug ignites the air fuel mixture to start the engine. The engine also includes many other disclosed features.

Methods and systems for operating an engine with different fuels having different cetane levels are described. In one example, start of fuel injection timing for engine cylinders may be adjusted responsive to engine deceleration or combustion phase during engine cranking. The start of fuel injection timing may be retarded for higher cetane fuels and advanced for lower cetane fuels.

In response to a restarting request generated during a stopping period, in which fuel injection is stopped to automatically stop engine operation, either starter starting or combustion starting is selected. In the starter starting, the engine is restarted using a starter motor. In the combustion starting, the engine is restarted through fuel injection and ignition without using the starter motor. If the rotational resistance acting on the crankshaft is determined to be of such a magnitude that the combustion starting is impossible, the starter starting is carried out in response to the restarting request generated during the stopping period.

A device for operatively connecting an engine starter to an engine where the engine includes an engine crankshaft and the engine starter has a starter shaft with a length and a worm, or worm screw, of a worm drive spaced radially from the starter adapter shaft and within the length of the shaft is described herein. The device compromises a worm gear assembly as operatively attached to the starter adapter shaft. The a worm gear assembly includes a worm gear, or worm wheel, positioned to engage the worm and an overrunning clutch positioned radially between the worm gear and the starter adapter shaft and operatively engaging the starter adapter shaft.