The control apparatus operates an engine water temperature adjustment apparatus so that the temperature of cooling water that passes through an engine head enters a first temperature region in a lean mode, and operates the engine water temperature adjustment apparatus so that the temperature of the cooling water enters a second temperature region that is lower than the first temperature region in a stoichiometric mode. When knocking is detected after switching is started from the stoichiometric mode to the lean mode, the control apparatus performs any one of a first operation to operate a variable valve apparatus so as to retard the closing timing of an intake valve, a second operation to operate an oil jet apparatus so as to increase an oil jet amount, and a third operation to operate an EGR apparatus so as to increase an EGR amount.

A system and method to selectively control intake air temperature of a dual fuel engine are provided. The dual fuel engine intake air temperature is automatically modified based on a determined fuel mode at which the dual fuel engine is operating or instructed to operate.

In order to prevent an abnormal combustion due to oil, a restriction region (B) is designated on a low-speed and high-load side of an internal combustion engine (1), and an opening of throttle valve (12) is restricted so that an engine operating condition is not observed within the restriction region (B). A predetermined designated inspection region (A) is set so as to include the restriction region (B), and it is judged whether or not the abnormal combustion actually occurred when the internal combustion engine (1) is running within the designated inspection region (A). If the abnormal combustion was detected, the restriction region (B) is expanded, meanwhile, if the abnormal combustion was not detected, the expanded restriction region (B) is gradually decreased. If the abnormal combustion occurred at a shorter interval than a threshold value, the restriction region (B) is expanded at once to a predetermined size.

An engine system for a vessel propulsion device includes an engine including an intake amount adjusting unit and an ignition plug, and configured to generate a drive force for the vessel propulsion device. The engine system includes an ignition timing control unit, a knocking detecting unit, a knocking retard control unit that retards the ignition timing of the ignition plug by a unit retard amount when the knocking detecting unit detects knocking, an abnormality judging unit that, when a state where the knocking detecting unit detects knocking at intervals within a predetermined time continues, judges that an abnormality has occurred based on a continued state of knocking detection, and an intake amount limiting unit that limits the intake amount of the engine based on judgment of an abnormality made by the abnormality judging unit.

A method for avoiding pre-ignitions during the operation of an internal combustion engine includes measuring a noise level of a combustion process using an acceleration sensor. An amplitude an amplitude of the measured noise level is measured to detect pre-ignitions. If, in the analysis, the measured noise level of a combustion cycle exceeds a limiting value n times, a safety operating mode of the internal combustion engine for reducing an effecting compression in the combustion chamber is activated. The safety operating mode is maintained if exceeding of the amplitude limiting value is also detected in subsequent combustion cycles of the internal combustion engine.

A control device for an internal-combustion engine to utilize low octane fuel and high octane fuel having a high octane value higher than a low octane value of the low octane fuel, the control device includes an inclination state sensor and a computer processor. The inclination state sensor detects an inclination state of a high octane fuel tank to store the high octane fuel. The computer processor acquires a remaining quantity of the high octane fuel in the high octane fuel tank. The computer processor restricts a power generated by the internal-combustion engine in accordance with the inclination state and the remaining quantity.

A control apparatus for an internal combustion engine, includes circuitry. The circuitry is configured to control a ratio of an amount of low octane number fuel to be supplied to a cylinder to a total amount of the low octane number fuel and a high octane number fuel to be supplied to the cylinder in order to control an overall octane number of fuel to be supplied to the cylinder. The high octane number fuel has a second octane number higher than a first octane number of the low octane number fuel. The circuitry is configured to calculate a maximum octane number of the fuel to be supplied into the cylinder. The circuitry is configured to restrict a power generated by the internal combustion engine based on the maximum octane number.

Methods and systems are provided for a boosted engine having a split exhaust system. In one example, a method comprises directing exhaust from a first cylinder group to one or more of a pre-compressor location, a post-compressor location, and an exhaust turbine, and directing exhaust from a second cylinder group to one or more of the pre-compressor location, and the exhaust turbine. Engine efficiency and knock control may be enhanced by directing exhaust gases to different locations based on engine operating conditions.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

Systems, methods and apparatus for controlling operation of dual fuel engines are disclosed that regulate the fuelling amounts provided by a first fuel and a second fuel during operation of the engine. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The fuelling amounts are controlled to improve operational outcomes of the duel fuel engine.