An engine start control device includes an pass determination section that performs a pass determination process of determining, based on a rotation state of the engine output shaft, whether a piston in a cylinder of the engine can pass over a compression top dead center for a rotation drop period in response to an occurrence of the start request. The engine start control device also includes a start control section that when it is determined that the piston cannot pass over the compression top dead center, starts driving of the motor in a low reaction force period to start the engine, the low reaction force period being a period in which a reaction force applied to the piston by a cylinder internal pressure in the cylinder is a predetermined value or less.

A start control system for an engine is provided. The engine is a direct injection engine, and the engine is provided with a starter motor. The start control system includes an electronic control unit. The electronic control unit is configured to execute fuel injection and ignition in a cylinder in an expansion stroke so as to start the engine without using the starter motor, when the electronic control unit determines that a restart condition of the engine is satisfied immediately before the engine is stopped. The electronic control unit is configured to control an ignition delay time based on at least one of a rotational direction and a rotational speed of a crankshaft, during execution of the fuel injection. The ignition delay time is a period of time from fuel injection into the cylinder in the expansion stroke to ignition.

Disclosed is a method for estimating a physical stoppage of an engine of a motor vehicle, subject to bounce-back, a target equipped with teeth being borne by the crankshaft and successive passes of the teeth past a sensor being detected, a first time count incrementing since a last detection of the passing of a tooth and being associated with a first time threshold with the first count being reset to zero when the time between passes of two successive teeth is below the first threshold. A second count associated with a second time threshold is performed, with this count being suspended when and for as long as a time between the passes of two successive teeth is below the second threshold, the engine being estimated to have stopped as soon as the counts have respectively reached the first and second thresholds.

A system and method of an electric tool (100) for facilitating starting of an engine, comprising a tool bit (102) having a bit portion (102A) arranged to engage with a rotatable component of a starter module of the engine, and a transmission mechanism (112) arranged to transfer a rotational movement provided by a motor (104) housed within a casing (110) of the electric tool to the bit portion, wherein the motor is arranged to be powered by a power source connected thereto, and wherein the rotational movement provided by the motor is transferred to the rotatable component of the starter module via the transmission mechanism only if the bit portion is engaged with the rotatable component.

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.

An ECU is applied to an engine system including an engine and an MG. The ECU determines whether or not a piston is located at a position, at which compression reactive force is received, at a time point at which engine speed reaches zero after combustion of the engine is stopped. Further, in a case where the ECU determines that the piston is located at the position at which compression reactive force is received, the ECU stops the piston by applying positive torque on a positive rotation side to a crank shaft by the MG.

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.

When an engine is stopped, a rotational position at a time when a crankshaft starts rotating in a reverse direction is predicted based on a rotational position detected by a crank angle sensor. A target rotational position is set within a range of the crankshaft rotational position between a time when the exhaust valve of one of four cylinders in the expansion stroke when the crankshaft starts rotating in the reverse direction is opened and a time when the expansion stroke of the cylinder ends. When the predicted rotational position is behind the target rotational position, a torque applying device applies a positive rotational torque to the crankshaft. At the time when the exhaust valve of the cylinder in the expansion stroke when the crankshaft starts rotating in the reverse direction is opened, application of the positive rotational torque from the torque applying device to the crankshaft is stopped.

An engine automatic stop/restart device includes an ignition-prohibition-decision unit that prohibits an ignition for an engine, which is controlled by the ignition-control unit, when a reverse rotation of the engine is detected based on a crank-angle signal; and an ignition-prohibition-release-decision unit that releases an ignition prohibition, after the ignition is prohibited by the ignition-prohibition-decision unit; in which the ignition-prohibition-release-decision unit releases the ignition prohibition when regular rotational signals of the engine, of which count is greater than or equal to a predetermined count, is detected and an engine revolution number is greater than or equal to a predetermined revolution number, after the reverse rotation of the engine is detected, and before a crank is positioned at a compression top dead center of the engine.

In the cases where a reverse operation of a crankshaft is performed after fuel injection and ignition in a cylinder in a power stroke and it is determined that an engine start is failed, a starter motor is operated, and fuel injection and ignition are executed in the cylinder in the compression stroke to start an engine.