The invention includes methods and devices for preventing excessive NOx formation during the combustion event of a compression-ignition engine with any combustible fuel (diesel, Jet-A, JP8, bio fuel, etc).

A method to control the combustion of an internal combustion engine, which comprises determining a combustion model, which provides a spark advance depending on an objective value of the rate of water to be injected, on the rotation speed, on the intake efficiency and on an open-loop contribution of a combustion index; calculating a first closed-loop contribution of the spark advance depending on the combustion index; calculating a second closed-loop contribution of the spark advance depending on a quantity indicating the knocking energy; and calculating the objective value of the spark advance angle to be operated through the sum of the spark advance value provided by the combustion model and of the first closed-loop contribution or, alternatively, of the second closed-loop contribution.

Operating an internal combustion engine system includes feeding a stream of pressurized intake air to a plurality of cylinders in an engine for combustion with a methanol fuel. An engine parameter indicative of at least one of an exhaust NOx level or a change to the exhaust NOx level of the engine is monitored, and water injected into an intake conduit for the engine based on the monitored engine parameter to limit the exhaust NOx level of the engine. Related apparatus and control logic is disclosed.

A method of controlling water injection in an internal combustion engine for a motor vehicle in case of freezing cold weather. The method includes: controlling the quality of the water, having a first sub-step of disapproving the quality of the water if the electrical conductivity σ of the water is not zero nor close to zero when the temperature T of the water is 0° C. or less and a second sub-step of approving the quality of the water if the electrical conductivity σ of the water is zero or close to zero when the temperature T of the water is higher than −4° C., preferably higher than −2° C. The method further includes a second sub-step of preventing water injection if the quality of the water is disapproved and a third step of allowing water injection if the quality of the water is approved.

A method for determining an air mass in an air separator of a water direct injection system for injecting a water/fuel mixture into a combustion chamber of an engine of a motor vehicle. The air separator is disposed between a water pump for delivering water of the water/fuel mixture and a high-pressure pump for feeding the water/fuel mixture to a high-pressure injector for injecting the water/fuel mixture into the combustion chamber. The method includes increasing a pressure of the water from a first pressure value to a second pressure value by the water pump, determining a water volume delivered by the water pump during the increasing of the pressure of the water by the water pump, and determining the air mass in the air separator on a basis of the determined water volume delivered by the water pump.

The present invention relates to a method and a control unit for avoiding condensation of humidity in an intake system of an internal combustion engine after engine switch off. Condensed liquid in the intake system of the stopped engine can lead to icing, corrosion and a hydrostatic lock at the next engine start. To prevent such an engine damage, it is necessary to determine if and in which amount condensed liquid occurs in the cooled intake system and to initiate appropriate actions to eliminate the liquid therefrom. The present invention predicts the occurrence of condensation in the intake system of the cooled engine and initiates corrective measures at engine switch off and during the cooling down period.

An internal combustion engine having an exhaust duct through which pass exhaust gases; and a water-based operating liquid system which includes a tank, and a heating device, which is coupled to the tank and is designed to heat water-based operating liquid. The heating device includes a heating chamber having an inlet opening designed to receive ambient air and that allows heat to be transferred from the walls of the exhaust duct to the air received from the environment and comprises an outlet opening for the heated air; and a heat exchanger, which receives the heated air and is thermally coupled to the tank so as to release part of the heat of the heated air to the water-based operating liquid contained in the tank.

An engine system includes a combustion chamber including a cylinder formed in an engine and a piston configured to reciprocate inside the cylinder, a spark plug disposed in a ceiling part of the combustion chamber, and a water injection device configured to inject water into the combustion chamber through a plurality of nozzle holes facing the inside of the combustion chamber. The piston has a cavity in an upper surface thereof. The water injection device injects water into the cavity in a compression stroke at a timing when an extension of axes of at least some of the nozzle holes intersects the cavity. The cavity has a bottom part where the water injected by the water injection device collides, and a raising part configured to raise the water spreading along the bottom part toward the water injection device.

An engine system is provided, which includes an engine configured to generate a motive force for a vehicle by combusting a mixture gas of fuel and intake air, a water injector configured to inject heated water into a combustion chamber of the engine, and a controller configured to control the water injector to inject the water into the combustion chamber during an expansion stroke of the engine. The controller acquires a demanded engine load of the engine, and controls the water injector to increase an amount of water injection when the demanded engine load is within a first-load range, compared to when the demanded engine load is within a second-load range where the engine load is higher than in the first-load range.

An engine system is provided, which includes an engine configured to generate a motive force for a vehicle by combusting a mixture gas of fuel and intake air, a water injector configured to inject heated water into a combustion chamber of the engine, and a controller configured to control the water injector to inject the water into the combustion chamber during an expansion stroke of the engine. The controller acquires a demanded engine load of the engine, and controls the water injector to retard a start timing of the water injection when the demanded engine load is within a first-load range, compared to when the demanded engine load is within a second-load range where the engine load is lower than in the first-load range.