A combustion system is applied to an engine. The combustion system includes an injection device that injects a fuel into a combustion chamber, a spark plug that ignites fuel in the combustion chamber, and a control device that controls the injection device and the spark plug. The control device includes a first control unit that executes predetermined first control. In the first control, control is performed such that, a total injection amount corresponding to all the fuel injected by the injection device in one combustion cycle of the engine is injected within a first period corresponding to a period from valve close timing which brings an intake valve into a closed state until a first half of a compression stroke of the engine ends.

An air-assisted jet flame ignition device includes a housing, a fuel-air premixing unit, and a prechamber. The fuel-air premixing unit includes a fuel injector, an air injection valve, a premixing sleeve, a premixing sleeve inner core placed in the premixing sleeve, and a fuel injector fastening bolt. An inner wall surface of the premixing sleeve and an outer wall surface of the premixing sleeve inner core form a premixing sleeve inner cavity. An inner wall surface of the premixing sleeve inner core, a lower end surface of a nozzle of the fuel injector, and an upper end surface of an air inlet of the air injection valve form a premixing cavity. The premixing cavity coupled to the premixing sleeve inner cavity via a through hole on the sidewall of the premixing sleeve inner core. A prechamber nozzle is fixedly coupled to the lower part of the housing.

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.

An internal combustion engine for driving a working assembly with a clutch, including a combustion chamber into which a mixture of fuel and air is supplied, a spark plug to ignite the mixture, ignition of the mixture driving a piston operably coupled to a crank portion of the engine, a fuel supply system including a fuel valve and a throttle valve, a throttle position sensor configured to determine a position of the throttle valve, a speed sensor configured to determine engine speed, and an electronic control unit configured to control operation of the fuel valve and the spark plug, the electronic control unit being configured to initiate a speed limitation operation in response to a first position of the throttle valve at engine start-up, wherein the speed limitation operation continues until the throttle valve is moved from its first position.

A method for starting an internal combustion engine comprises the steps of: providing an internal combustion engine having at least one cylinder and a piston supported at a crankshaft for repeated reciprocal movement in the cylinder so as to define a main combustion chamber, the internal combustion engine further having an ignition device arranged in said cylinder with an igniter portion and a fuel injector which are both arranged at a pre-chamber, wherein the pre-chamber has a plurality of orifices for providing fluid communication between said pre-chamber and the main combustion chamber, injecting fuel in the pre-chamber, and igniting the injected fuel in the pre-chamber for pre-heating of the pre-chamber prior to injecting fuel in the main combustion chamber for combusting the injected fuel in the main combustion chamber.

Methods and systems are provided for restarting an engine following an engine idle-stop. In one example, a method may include, prior to an engine restart following an idle-stop, adjusting a spark ignition timing based on an estimation of a fuel-air equivalence ratio (phi) and an estimation of a cylinder turbulence. Optimal spark ignition timing based on estimated phi and cylinder turbulence during engine restart may result in stabilized combustion and a torque output sufficient to at least partially relieve demand on the starting device.

A fuel injector is configured so that, when seen from a top view of a combustion chamber, a first fuel spray flux and a second fuel spray flux sandwich an electrode part of a spark plug, and the electrode part is located outside of contour surfaces of the two fuel spray fluxes. A first injection angle between a center line of the first fuel spray flux and a vertical line and a second injection angle between a center line of the second fuel spray flux and the vertical line are larger than an angle between a center line of any other fuel spray flux and the vertical line. The second injection angle is made smaller than the first injection angle so that a distance from the electrode part to the contour surface of the second fuel spray flux is larger than a distance from the electrode part to the contour surface of the first fuel spray flux.

An upper part of FIG. 7 represents a catalyst warming-up control when a normal fuel is used, and a lower part of FIG. 7 represents the catalyst warming-up control when a heavy fuel is used. As understood from a comparison between the upper part and the lower part of FIG. 7, the start timing of the ignition period and the total injection amount of the injector in each cycle when the heavy fuel is used are the same as those when the normal fuel is used, though the ratio of the intake stroke injection and the expansion stroke injection to the total injection amount of the injector is changed to increase the fuel amount of the expansion stroke injection as compared with the case where the normal fuel is used.

A control device for an internal combustion engine is programmed, during a catalyst warm-up control, to perform first fuel injection by an injector in an intake stroke, control an ignition device so as to generate a discharge spark in a predetermined period in an expansion stroke, and perform second fuel injection, at a timing retarded from a compression top dead center, such that its injection period overlaps with at least a part of the predetermined period and an end timing of the injection period is advanced from an end timing of the predetermined period. Further, the control device is programmed, during the catalyst warm-up control, to control an actual tumble ratio depending on a result of determination using a first index value representing a speed of initial combustion accompanying an ignition by the ignition device and a second index value representing a speed of main combustion accompanying the ignition.

Systems and methods for generating auxiliary torque are provided. In one example, a method for controlling a supercharger comprises, responsive to requested torque exceeding spark authority of an engine, varying a current applied to a motor of the supercharger to provide an amount of torque to a crankshaft of the engine. In this way, a supercharger can be controlled to compensate for an engine torque shortfall.