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.

An engine output control device controls engine output at a time of a downshift speed change of a transmission. The engine output control device includes: engine speed detecting means for detecting an actual engine speed NeJ of a crankshaft; and engine output adjusting means capable of adjusting the engine output according to an operation of a rider. The smaller of a requested engine output PA calculated on a basis of the actual engine speed NeJ and a rider requested engine output PB adjusted by the engine output adjusting means is output as the engine output.

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.

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.

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.

A control device is configured to perform, when it is estimated that a combustion fluctuation increases, estimation related to an ignition delay for initial flame generated from a discharge spark and an air-fuel mixture containing fuel spray injected by intake stroke injection. When it is estimated that the ignition delay for the initial flame is increased from that before the increase in the combustion fluctuation, an injection amount in expansion stroke injection is reduced in a next time cycle. When it is estimated that the ignition delay for the initial flame is reduced from that before the increase in the combustion fluctuation, the injection amount in expansion stroke injection is increased in a next time cycle.

The present invention describes a fuel-management system for minimizing particulate emissions in turbocharged direct injection gasoline engines. The system optimizes the use of port fuel injection (PFI) in combination with direct injection (DI), particularly in cold start and other transient conditions. In the present invention, the use of these control systems together with other control systems for increasing the effectiveness of port fuel injector use and for reducing particulate emissions from turbocharged direct injection engines is described. Particular attention is given to reducing particulate emissions that occur during cold start and transient conditions since a substantial fraction of the particulate emissions during a drive cycle occur at these times. Further optimization of the fuel management system for these conditions is important for reducing drive cycle emissions.

The present invention describes a fuel-management system for minimizing particulate emissions in turbocharged direct injection gasoline engines. The system optimizes the use of port fuel injection (PFI) in combination with direct injection (DI), particularly in cold start and other transient conditions. In the present invention, the use of these control systems together with other control systems for increasing the effectiveness of port fuel injector use and for reducing particulate emissions from turbocharged direct injection engines is described. Particular attention is given to reducing particulate emissions that occur during cold start and transient conditions since a substantial fraction of the particulate emissions during a drive cycle occur at these times. Further optimization of the fuel management system for these conditions is important for reducing drive cycle emissions.