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.

Disclosed is a multiple combustion mode engine with ammonia fuel including an cylinder head, a cylinder sleeve, a piston, a main combustion chamber, an inlet valve and an exhaust valve, and further including a jet ignition device arranged on the cylinder head and used for providing an ignition source for the main combustion chamber, and an ammonia injector used for providing ammonia/air mixture gas for the main combustion chamber. Also disclosed is a control method of the multiple combustion mode engine with ammonia fuel. The time sequence of ammonia injection of the main combustion chamber and jet flame generation of the pre-chamber is controlled, the mixed state of the fuel/air in the main combustion chamber before ignition can be controlled, and finally different combustion modes, i.e. a premixed combustion mode and a diffusion combustion mode, are formed in the main combustion chamber.

To provide a controller for internal combustion engine which can improve the estimation accuracy of the period in the chipped tooth section, even if the period is suddenly varied in the chipped tooth section. A controller for internal combustion engine detects a period when the tooth passes, based on an output signal of the crank angle sensor; determines a period corresponding to the chipped tooth section; determines a crank angle corresponding to the passed tooth; and estimates a period of a virtual unit angle interval when assuming that the tooth is provided at the unit angle interval in the chipped tooth section, based on the period of the chipped tooth section, the period before the chipped tooth section, and the period after the chipped tooth section.

A system and method for self-adjusting engine performance parameters in response to fuel quality variations that includes an exhaust sensor for measuring a level of carbon dioxide present in an exhaust manifold, at least one of a knock sensor and a cylinder pressure transducer for determining a location of peak pressure and a centroid, respectively, a controller in communication with the exhaust sensor and the at least one of the knock sensor and the cylinder pressure transducer, the controller correlating a methane number of the fuel used by the engine to a brake specific carbon dioxide value calculated using the level of carbon dioxide measured by the exhaust sensor and the at least one of the centroid and the location of peak pressure, and an adjusting mechanism, wherein the adjusting mechanism adjusts an engine performance parameter based on the determined methane number.

To accurately estimate a combustion state even in a case where the combustion state in a combustion chamber greatly changes. According to an aspect of the present invention, an internal combustion engine control device 12 includes a rotational speed calculation unit 122a that calculates a crank rotational speed of an internal combustion engine, an extreme value timing calculation unit 122b that calculates an extreme value timing at which the crank rotational speed calculated by the rotational speed calculation unit 122a becomes an extreme value, a combustion-state-calculation-means selection unit 122c that selects combustion state calculation means for calculating a combustion state in a combustion chamber based on an operation state of the internal combustion engine, and a combustion state estimation unit 122d that estimates the combustion state in the combustion chamber from the extreme value timing of the crank rotational speed by using the combustion state calculation means selected by the combustion-state-calculation-means selection unit 122c.

The subject matter of this specification can be embodied in, among other things, a method performed in connection with an internal combustion engine, and the method including receiving a pressure signal from a combustion chamber pressure sensor during a first range of volumes, the first range corresponding to a portion of a compression phase, the received pressure being a first pressure, providing, based on the received pressure signal, a first pulse of fuel at a first position of the body during the compression phase, and providing, based on the received pressure signal a second pulse of fuel at a second position of the body during the compression phase.

Provided is a control device and a control method of a high-efficiency internal combustion engine capable of stabilizing combustion and suppressing NO.sub.x emissions without unnecessarily increasing a mounting load on an ECU. Therefore, the control device of the internal combustion engine for controlling the internal combustion engine includes an ignition plug that ignites an air-fuel mixture of fuel and air in the combustion chamber, a combustion pressure estimation sensor that detects a combustion pressure in the combustion chamber, and a crank angle sensor that detects a crank angle of a crankshaft. An MBT region is set based on an ignition delay period from an ignition timing of the ignition plug calculated from a detection value of the combustion pressure estimation sensor and a detection value of the crank angle sensor to a combustion start timing in the combustion chamber, and a combustion period from the combustion start timing to a set amount combustion end timing when a set amount of combustion ends. An ignition timing of the ignition plug is controlled so as to fall within the set MBT region.

A method of controlling an engine is provided, which includes, during motoring of the engine, injecting, by an injector, fuel for analysis into a cylinder of the engine at a specific timing after an intake valve of the cylinder is closed. The method includes acquiring, by a controller, a crank angle period from a start timing of the fuel injection to a timing of a pressure inside the cylinder reaching a reference pressure, in response to signals of a crank angle sensor and an in-cylinder pressure sensor. The method includes determining, by the controller, a property of the fuel injected by the injector by comparing the acquired crank angle period with a reference crank angle period, the reference crank angle period being from an injection start timing when a standard fuel is injected into the cylinder to a timing of the pressure inside the cylinder reaching the reference pressure.

An engine controlling method is provided, which includes, during motoring of the engine, outputting, by an in-cylinder pressure sensor, to a controller a signal indicative of a reference pressure corresponding to a pressure change after an intake valve of a cylinder of the engine is closed when not performing fuel injection, and then injecting, by an injector, fuel for analysis into the cylinder at a specific timing after the intake valve is closed. The method includes, by the controller, acquiring a crank angle period from the intake valve close timing, through the fuel injection, to a timing of the in-cylinder pressure reaching the reference pressure based on signals from the in-cylinder pressure sensor and a crank angle sensor, and determining a property of the injected fuel by comparing the acquired crank angle period with that of a standard fuel based on stored information on a property of the standard fuel.

A method of controlling an engine is provided, which includes the steps of, during motoring of the engine, injecting, by an injector, fuel for analysis into a cylinder at a specific timing after an intake valve of the cylinder of the engine is closed, outputting to a controller, by an in-cylinder pressure sensor, a signal corresponding to a pressure inside the cylinder at least at a timing when a specific crank angle period has passed from the fuel injection timing, and determining, by the controller, a property of the fuel injected by the injector, by comparing a pressure value measured by the in-cylinder pressure sensor with a reference pressure value inside the cylinder measured at a timing when the specific crank angle period has passed after a standard fuel is injected into the cylinder at the specific timing.