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.

Methods and apparatus are disclosed for vehicle charge control for protection against cold crank failure. An example vehicle includes a battery and a body control module. The body control module is to obtain state of charge information of the battery, obtain temperature information, and estimate a next crank time based on the state of charge information and the temperature information.

A vehicle includes an engine, an electric machine, and a controller. The electric machine is configured to start the engine. The controller is programmed to pre-flux the electric machine with current that has a magnitude that changes as temperature of the engine changes within a predefined range.

A hybrid electric powertrain includes an electric machine delivering torque to an engine in an engine start event having initial cranking and transition phases. In response to a request for an engine start event, a controller commands delivery of the motor torque to the crankshaft. In the initial cranking phase the controller regulates crankshaft acceleration from zero speed up to a target cranking speed in a closed-loop manner via a predetermined fixed profile. In the transition phase, the crankshaft accelerates from the target cranking speed to a target idle speed using a feed-forward torque value blended, using a calibration table, from a predetermined engine drag torque to a reported engine torque. In the transition phase the controller periodically adjusts a speed trajectory of the crankshaft, with the magnitude and frequency of adjustment based on combustion of the engine and calibration of the feed-forward torque.

A vehicle includes an engine, an electric machine, and a controller. The electric machine is configured to start the engine. The controller is programmed to pre-flux the electric machine with current that has a magnitude that changes as temperature of the engine changes within a predefined range.

A vehicle includes an engine and a controller. The controller may be configured to, responsive to indication of a temperature of a starter-generator exceeding a de-rated threshold, command the engine to start and disable engine automatic shut-off. And the controller may be configured to, responsive to indication of the temperature exceeding a disabled threshold, or the temperature exceeding the de-rated threshold and a traction battery discharge power being less than a threshold, command the engine to start and shed a load.

An electric starter system is usable with a powertrain having an engine with a flywheel. The starter system includes a brushless starter motor having a machine temperature, and a solenoid operable for translating a pinion gear into meshed engagement with the flywheel and the starter motor in response to a requested engine start event. A controller has temperature regulation logic that includes a proportional-integral torque control loop. Execution of a method embodied by the logic, in response to the requested engine start event when the machine temperature exceeds a first temperature, causes the controller to determine a required starting torque of the starter motor using the control loop. The controller causes the starter motor to transmit the required starting torque to the engine at a level that reduces the machine temperature below the first temperature.

An electric starter system is usable with a powertrain having an engine with a flywheel. The starter system includes a brushless starter motor having a machine temperature, and a solenoid operable for translating a pinion gear into meshed engagement with the flywheel and the starter motor in response to a requested engine start event. A controller has temperature regulation logic that includes a proportional-integral torque control loop. Execution of a method embodied by the logic, in response to the requested engine start event when the machine temperature exceeds a first temperature, causes the controller to determine a required starting torque of the starter motor using the control loop. The controller causes the starter motor to transmit the required starting torque to the engine at a level that reduces the machine temperature below the first temperature.

Methods and apparatus are disclosed for vehicle charge control for protection against cold crank failure. An example vehicle includes a battery and a body control module. The body control module is to obtain state of charge information of the battery, obtain temperature information, and estimate a next crank time based on the state of charge information and the temperature information.

A hybrid electric powertrain includes an electric machine delivering torque to an engine in an engine start event having initial cranking and transition phases. In response to a request for an engine start event, a controller commands delivery of the motor torque to the crankshaft. In the initial cranking phase the controller regulates crankshaft acceleration from zero speed up to a target cranking speed in a closed-loop manner via a predetermined fixed profile. In the transition phase, the crankshaft accelerates from the target cranking speed to a target idle speed using a feed-forward torque value blended, using a calibration table, from a predetermined engine drag torque to a reported engine torque. In the transition phase the controller periodically adjusts a speed trajectory of the crankshaft, with the magnitude and frequency of adjustment based on combustion of the engine and calibration of the feed-forward torque.