A gas engine 1 which operates in stoichiometric mode under high-load conditions and which operates in lean burn mode under medium- and low-load conditions includes a valve 2 which supplies the gas engine 1 with an air-fuel mixture composed of air and fuel gas. In the valve 2, a valve unit 21 for stoichiometric operation is connected in series to a valve unit 22 for lean burn operation and is also connected to a mixer 24. An opening area of the valve 2 is controlled in such a manner as to ensure a predetermined opening area for effecting stoichiometric operation, to uniformly decrease the opening area over time until a switching operation from stoichiometric operation to lean burn operation ends, to ensure a predetermined opening area for effecting lean burn operation, and to uniformly increase the opening area over time until a switching operation from lean burn operation to stoichiometric operation ends.

A motor response control method in a variable charge motion system in which a VCM motor is differentially controlled by a PWM duty regardless of back pressure of intake air in an intake manifold when a current engine rotation speed in revolutions per minute is less than a specific engine rotation speed in revolutions per minute in a VCM position learning state by a controller whereas the VCM motor is differentially controlled by the PWM duty based on the back pressure of intake air in the intake manifold when the current engine rotation speed in revolutions per minute is greater than the specific engine rotation speed in revolutions per minute.

An internal combustion engine for an automotive vehicle has an intake manifold receiving fresh air via an inlet duct. The engine includes a crankcase. A turbocharger is provided having a compressor with an inlet coupled to the inlet duct and an outlet coupled to the intake manifold. A first vent line couples the crankcase with the compressor inlet. A second vent line couples the crankcase with the compressor outlet and intake manifold. The second vent line has a valve blocking air flow into the crankcase and allowing air flow out from the crankcase. The first vent line comprises a dual-acting valve having a first flow capacity into the crankcase and a second flow capacity out from the crankcase which is greater than the first flow capacity. Thus, crankcase ventilation is optimized for both engine idle and high engine load conditions.

An engine control apparatus includes an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be lower when an in-cylinder temperature specified by an in-cylinder temperature specification section is high than when the in-cylinder temperature is low.

Methods and systems are provided for operating a high pressure injection pump to provide each of high fixed fuel pressure at a port injection fuel rail and high variable fuel pressure at a direct injection fuel rail. Port injection fuel rail pressure can be raised above a pressure provided with a lift pump via a fuel system configuration that includes various check valves, pressure relief valves, and a spill valve positioned between an inlet of the high pressure injection pump and the port injection fuel rail. High pressure port injection may be advantageously used to provide fuel at high pressure during conditions when fuel delivery via high pressure direct injection is limited.

Methods and systems for operating an engine and determining relative compression ratio differences from a reference cylinder are disclosed. In one example, an engine is rotated via a starter or another type of electric machine and engine deceleration rates related to each engine cylinder are determined. The engine deceleration rates form a basis for compression ratio factors for each engine cylinder.

To optimize fuel supply of an engine with a carburetor during engine operation, a throttle opening degree detection sensor detecting a throttle opening degree and a control unit controlling a valve body variably controlling an opening degree of a fuel discharge part or a fuel supply passage based on a map are included. The map includes a plurality of sections divided based on the throttle opening degree and an opening degree of the valve body set for each section. The opening degree of the valve body set for each section is the opening degree of the valve body at which the engine rotation speed is highest in each section. The control unit controls an electric actuator driving the valve body to achieve the opening degree of the valve body set in a section to which the throttle opening degree detected by the throttle opening degree detection sensor belongs out of the plurality of sections.

The ECM calculates a peak value of an in-cylinder pressure before ignition based on the operating state of the hydrogen engine. When the peak value of the in-cylinder pressure before ignition exceeds a threshold value, the ECM performs an advancement correction of the ignition timing such that the peak value becomes less than or equal to the threshold value.

An ignition system for an internal combustion engine includes a prechamber ignition device, a fuel admission valve for the prechamber ignition device, and a combustion consistency control mechanism configured to receive data indicative of at least one of a magnitude of a peak pressure in a combustion prechamber of the prechamber ignition device or a timing of the peak pressure in the combustion prechamber. The combustion consistency control mechanism calculates an error based on the data, and outputs a valve opening command to a fuel valve to produce a shot of combustion-initiating gases from the prechamber device, the valve opening command being based on the error.

To optimize fuel supply of an engine with a carburetor during engine operation, a throttle opening degree detection sensor detecting a throttle opening degree and a control unit controlling a valve body variably controlling an opening degree of a fuel discharge part or a fuel supply passage based on a map are included. The map includes a plurality of sections divided based on the throttle opening degree and an opening degree of the valve body set for each section. The opening degree of the valve body set for each section is the opening degree of the valve body at which the engine rotation speed is highest in each section. The control unit controls an electric actuator driving the valve body to achieve the opening degree of the valve body set in a section to which the throttle opening degree detected by the throttle opening degree detection sensor belongs out of the plurality of sections.