Methods and systems are provided for starting an engine via an electric turbocharger. In one example, a method for starting the engine via the electric turbocharger may include flowing compressed air from the electric turbocharger to cylinders of the engine to crank a crankshaft of the engine without a starter motor. The method may include adjusting an opening amount of electrically or pneumatically actuated intake valves and exhaust valves to reduce a force to crank the crankshaft.

A control apparatus is applied to an internal combustion engine that is capable of implementing reduced-cylinder operation and all-cylinder operation. When the internal combustion engine is stopped during implementation of reduced-cylinder operation, and then the internal combustion engine is restarted in reduced-cylinder operation with the same cylinders as idling cylinders, the initial crank angle when cranking starts is controlled so that the position of the piston of at least one among the idling cylinders is in the vicinity of its top dead center.

A disclosed method of automatically stopping and restarting a vehicle engine determines if one or more stop/start enablement condition has been met. If the stop/start enablement condition or conditions have been met, the method initiates an engine shutdown. If a restart request is made before the engine reaches a predetermined threshold speed, then a first restart sequence is initiated. If a restart request is made when the engine speed is less than the predetermined threshold speed but still greater than 0, then a second restart sequence is initiated.

A control device for an internal combustion engine is configured to: execute a first decompression operating processing such that a decompression operating state is selected in a first engine speed region that passes in the course of engine stop; execute a decompression stop processing such that a switching from the decompression operating state to a decompression stop state is performed in the course of the engine stop after passage of the first engine speed region; when a temperature correlation value is greater than or equal to a threshold value upon an engine start-up request, execute a second decompression operating processing such that the decompression operating state is selected in a second engine speed region that passes in the course of engine start-up before the start of fuel injection. When the temperature correlation value is smaller than the threshold value, the second decompression operating processing is not executed.

Methods and systems are provided for compression heating of air. In one example, a method may include, during an engine start and prior to a first combustion event, deactivating cylinder exhaust valves while spinning the engine electrically and unfueled until a threshold intake air temperature is reached, and alternately activating and deactivating the exhaust valves of one or more cylinders to maintain the intake air temperature above the threshold temperature after the first combustion event. In this way, a temperature of an air charge may be increased, resulting in increased fuel economy and decreased vehicle emissions.

Systems, apparatuses and methods are disclosed that include an internal combustion engine including a plurality of cylinders operable by a valve actuation mechanism including a lifting mechanism having a compression brake valve profile configured to selectively lift the exhaust valves on a downstroke of the cylinders in response to a cranking condition of the internal combustion engine, wherein the compression braking valve profile is phased to the upstroke of the pistons.

Provided is a control device for controlling an internal combustion engine including a fuel injection valve, an ignition device, and a variable valve operating device configured to switch between a base opening/closing mode of an intake valve and a continuous valve opening mode. The control device is configured to execute a cold start control at a cold start. The cold start control includes: a startability improvement processing executed in a predetermined number of cycles after the start of cranking; and a combustion start processing executed after this predetermined number of cycles. In the startability improvement processing, the continuous valve opening mode is selected in at least an expansion stroke and an exhaust stroke, and fuel injection is executed without ignition. In the combustion start processing, the base opening/closing mode is selected continuously during one cycle, and ignition is executed.

Provided is a hybrid vehicle that includes a power train including an internal combustion engine equipped with a plurality of cylinders and a drive motor unit. The drive motor unit includes an electric motor coupled to the internal combustion engine without a clutch. The internal combustion engine includes one or more decompression devices that are each installed for a subset of one or more cylinders and that operate to release compression pressure in the subset of one or more cylinders in at least one of the course of an engine stop and course of an engine start-up in which combustion is not performed. The subset of one or more cylinders are selected such that, when the one or more decompression devices are operating, compression is not produced sequentially in cylinders that are adjacent to each other in terms of the firing order.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, the engine system may be installed in a hybrid vehicle, and, in response to a request to restart the engine while the vehicle is being propelled via motor torque only, the engine may be rotated unfueled via the motor torque at less than cranking speed while at least partially opening a valve disposed in a passage coupled between the first exhaust manifold and the intake passage. In another example, in response to the request to restart the engine, all exhaust valves of a second set of exhaust valves coupled to the second exhaust manifold may be deactivated.

A number of variations may include a method comprising controlling the combustion phase timing in the first firing cycle of a start/stop combustion engine comprising: providing a camshaft operatively connected to an extended range intake cam phaser; fully or partially retarding the extended range intake cam phaser during an engine restart to control a position of the camshaft and prevent pre-ignition; and retarding a spark timing in the first cylinder to delay the combustion phase timing to improve NVH.