Methods and systems are provided for providing compression release during a stop/start event in an engine. In one example, a method includes: responsive to a request for a stop/start event in an engine with a continuously variable valve lift (CVVL) system including a compression release hydraulic valve actuator coupled to a valve of a first cylinder, determining a desired stop position of the engine; and prior to restarting the engine during the stop/start event, adjusting the compression release hydraulic valve actuator to open the valve during a compression stroke of the first cylinder. In this way, an amount of torque used to restart the engine may be reduced.

The disclosure relates to a method for controlling an internal combustion engine configured with a belt starter generator or an electric machine of a hybrid powertrain. The internal combustion engine includes a cylinder and a piston, which together delimit a working chamber. The internal combustion engine includes a variable valve actuation system for actuation of inlet valves of the working chambers, controlling the opening time and/or the closing time and/or the lift. A strategy for operating the internal combustion engine with a negative drive torque or when shutting down or when starting up the internal combustion includes controlling the inlet valves of individual or all working chambers in such a way that the transfer of fresh air from an intake section to an exhaust manifold is controlled and that the drag torque of the internal combustion is reduced.

A prime mover for a lightweight vehicle comprising an internal combustion engine, a starter motor integrally integrated with the internal combustion engine, and a housing for the prime mover. The prime mover additionally comprises a Hall Effect sensor and an prime mover control module structured and operable to communicate with the Hall Effect sensor, determine when operation of the internal combustion engine should cease, and upon the determination that operation of the internal combustion engine should cease, utilize the communication from the Hall Effect sensor to stop the internal combustion engine such that a piston of the internal combustion engine is positioned at between 15° and 25° after bottom-dead-center.

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.

Methods and systems are provided for performing expansion combustion in an engine of a start-stop vehicle. In one example, a method may include, responsive to receiving an auto-start request to restart an engine from an auto-stop, determining a fuel mass to inject into a cylinder for an expansion combustion event based on a duration of the auto-stop, and actuating a spark plug of the cylinder after injecting the determined fuel mass to perform the expansion combustion event. In this way, an air-fuel ratio of the expansion combustion event may be more accurately controlled, resulting in more robust expansion combustion engine restarts.

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.

A method for operating a vehicle that includes a DC/DC converter is described. In one example, the method includes adjusting an output voltage of the DC/DC converter to increase torque of a belt integrated starter/generator. The output voltage of the DC/DC converter may be adjusted before and during engine cranking.

A method for stopping an engine within a desired crankshaft angular range is disclosed. In one example, the method may take no control actions if it is determined that the engine will stop within the desired crankshaft angular range. However, if it is determined that the engine may stop outside of the desired crankshaft angular range, expansion combustion may be initiated in a cylinder so that the engine stops in a desired crankshaft angular range.