Systems and methods for detecting and mitigating belt slip of an engine front end accessory drive are described. In one example, three different signals are input to a weighted average filter to determine the presence or absence of belt slip so that quality of an indication of belt slip may be improved.

A method for slow starting a reciprocating engine having a crankshaft, piston, and piston chamber is disclosed. The method includes applying a force to the crankshaft, sensing an engine characteristic, and determining if an error or fault is present in the engine.

An engine starter system includes a starter including a multi-phase brushless electric motor and an electronic commutator assembly. A controller includes an instruction set that is executable in response to a command to execute an engine starting event. Operation includes determining a desired starting profile, controlling the starter to engage a rotatable member of the engine, and monitoring the rotational speed of the electric motor via a rotor position sensing circuit. The starter inverter is dynamically controlled to control the electric motor to spin the rotatable member of the internal combustion engine responsive to the desired starting profile, including dynamically controlling the starter inverter to control the electric motor to control the spin of the engine responsive to the desired starting profile to prevent occurrence of an engine speed flare event during the engine starting event.

Upon a request for switching from a first travel mode of traveling with a clutch disengaged and operation of an engine stopped to a second travel mode of traveling with the clutch engaged and the engine operating, a controller for a hybrid vehicle restarts the engine in the following manner. That is, the controller restarts the engine in a first start mode of starting combustion in the engine with the clutch non-fully engaged when a rotation speed of a motor is greater than a determination value and restarts the engine in a second start mode of starting combustion in the engine with the clutch fully engaged when the rotation speed of the motor is less than or equal to the determination value.

An internal-combustion engine includes a belt-driven starter generator and makes an idling stop while a vehicle is at a stop. In the process of the engine revolution speed decreasing with cutting of fuel to stop the vehicle, to suppress the reduction in restart responsiveness caused by slack in a belt, preliminary powering of the starter generator is performed. The belt tension during deceleration microscopically changes periodically between a relatively high-tension period and a relatively low-tension period due to pulsation of the engine revolution speed. Slack in the belt does not occur in the high tension period, and thus preliminary powering torque is applied only in the low-tension period.

A control unit is provided for a vehicle having an internal combustion engine with a shaft, which can be coupled to an electric machine or decoupled from the electric machine. The control unit is designed to couple the electric machine to the internal combustion engine during an engine stop of the internal combustion engine. The control unit causes the electric machine to guide the shaft of the internal combustion engine. The control unit determines that a speed of the guided shaft is equal to or less than a speed threshold value and, in response thereto, decouples the electric machine from the internal combustion engine, such that the internal combustion engine stops without being guided by the electric machine.

Systems and methods for detecting and mitigating belt slip of an engine front end accessory drive are described. In one example, three different signals are input to a weighted average filter to determine the presence or absence of belt slip so that quality of an indication of belt slip may be improved.

There is provided an engine starting device, including: a motor generator coupled to a crankshaft of an engine; and a starter including a pinion provided in a detachable manner from a ring gear provided on the crankshaft, and configured to mesh with the ring gear when the engine is started, wherein the engine is cranked through simultaneous cranking by both of the motor generator and the starter when a condition set in advance is satisfied, and wherein, in the simultaneous cranking, the starter starts rotating after the motor generator starts rotating.

A hybrid electric vehicle control apparatus increases a speed of an engine in view of a speed of a drive motor when starting the engine, and turns on an engine clutch after identifying a self-operation of the engine, based on a disturbance torque, thereby rapidly synchronizing the engine speed and the drive motor speed and preventing waste of fuel, which in turn improves fuel efficiency.

A restart control system includes a rotational angle estimation unit that estimates a rotating electrical machine's rotational angle in a state wherein an internal-combustion engine's rotational speed detected by a rotational speed detection unit is higher than an estimation threshold and configured not to estimate rotating electrical machine's rotational angle in a state wherein internal-combustion engine's rotational speed is lower than estimation threshold; a rotating electrical machine control unit increases internal-combustion engine's rotational speed by rotating electrical machine under condition where predetermined restart conditions are satisfied and rotating electrical machine's rotational angle is estimated by rotational angle estimation unit, thereby restarting the internal-combustion engine; and a starter motor control unit starts driving of a starter motor under a condition where predetermined restart conditions are satisfied and internal-combustion engine's rotational speed falls below a predetermined rotational speed set lower than estimation threshold, thereby increasing internal-combustion engine's rotational speed to estimation threshold.