The control device (50) operates to: calculate the ignition timing of each cylinder (101) of an engine (100) based on whether or not knocking is occurring; set, as a reference ignition timing, the ignition timing of any of the cylinders (101) for which the ignition timing is on the advanced angle side relative to the most retarded angle ignition timing on the most retarded angle side and on the retarded angle side relative to the most advanced angle ignition timing on the most advanced angle side; set an allowable timing difference range that is a range of an allowable timing difference with reference to the reference ignition timing; and when determining that the ignition timing of a cylinder (101) falls outside the allowable timing difference range, correct the ignition timing so that the timing difference with respect to the reference ignition timing falls within the allowable timing difference range.

Methods and systems are provided for actively heating pistons in combustion chambers to decrease a torque imbalance in an engine. In one example, a method for operation of an engine includes determining a variation between compression ratios in a first combustion chamber and a second combustion chamber and operating a piston heating system to apply a targeted amount of heat to a first piston assembly based on the variation between the compression ratios, the first piston assembly including a first piston positioned within the first combustion chamber.

A method of operating a dedicated-EGR engine includes providing a rich air-fuel mixture to a dedicated cylinder; combusting the rich air-fuel mixture in the dedicated cylinder; modeling the combustion of the rich air-fuel mixture in the dedicated cylinder; estimating the composition of the combustion products in the dedicated cylinder based on interpolation of chemical reaction models of stoichiometric and rich combustion. The method further includes mixing the combustion products from the dedicated cylinder with air to produce an intake mixture; estimating a mass fraction of reformate and a mass fraction of burned gas in the intake mixture; providing the intake mixture to the intake ports of all of the cylinders of the dedicated-EGR engine; combusting an air-fuel mixture in a non-dedicated cylinder of the engine; and controlling an engine control parameter based on the estimated mass fractions of reformate and burned gas in the intake mixture.

A method for knock control of an internal combustion engine capable of being operated using a water injection system, in which at least one parameter of the knock control is determined as a function of a variable connected to the water injection system, in particular the water content.

An internal combustion engine includes an anisotropic thermal conductivity member (37, 51) provided on a wall surface defining a cylinder or a wall surface of a cooling water passage on a side of the cylinder, a thermal conductivity of the anisotropic thermal conductivity member in an axial direction of the cylinder being higher than a thermal conductivity of the anisotropic thermal conductivity member in a radial direction of the cylinder, and a thermally insulating member (38. 52) provided on an outer surface of the anisotropic thermal conductivity member with respect to the radial direction of the cylinder.

A method of operating a dedicated-EGR engine includes providing a rich air-fuel mixture to a dedicated cylinder; combusting the rich air-fuel mixture in the dedicated cylinder; modeling the combustion of the rich air-fuel mixture in the dedicated cylinder; estimating the composition of the combustion products in the dedicated cylinder based on interpolation of chemical reaction models of stoichiometric and rich combustion. The method further includes mixing the combustion products from the dedicated cylinder with air to produce an intake mixture; estimating a mass fraction of reformate and a mass fraction of burned gas in the intake mixture; providing the intake mixture to the intake ports of all of the cylinders of the dedicated-EGR engine; combusting an air-fuel mixture in a non-dedicated cylinder of the engine; and controlling an engine control parameter based on the estimated mass fractions of reformate and burned gas in the intake mixture.

An auxiliary chamber (51) having a spark plug (54) and an auxiliary fuel injector is formed at the central part of the top surface of the main combustion chamber (2). When making an air-fuel mixture in the auxiliary chamber (51) burn by the spark plug (54), an air-fuel mixture in the main combustion chamber (2) is made to burn by jet flames ejected from the communicating holes (52). The injection ports of the auxiliary fuel injector (53) are oriented toward a tumble flow inflow peripheral region (R) which is located on the peripheral part of the end portion of the auxiliary chamber (51) at a place located on a side where the tumble flow W flows in from the communicating holes (52). When the tumble flow (W) is made to be generated in the main combustion chamber (2) by the tumble flow control valve (48), auxiliary fuel (QF) is injected from the auxiliary fuel injector (53) toward the tumble flow inflow peripheral region (R) of the auxiliary chamber (51).

Methods and systems are provided for addressing spark plug soot fouling. In one example, a method may include alternating one or more combustion events with spark timing advanced with one or more combustion events with nominal spark timing. The approach allows spark plug over-heating, and related issues such as knock, to be reduced.

A controller for an internal combustion engine includes processing circuitry. The processing circuitry performs a dither control process. The dither control process includes a first mode in which a cylinder serving as a rich combustion cylinder is sequentially changed and a second mode in which a specified cylinder is fixed as one of a rich combustion cylinder and a lean combustion cylinder. The processing circuitry selects the first mode or the second mode based on an operating point of the internal combustion engine.

Methods and systems are provided for actively heating pistons in combustion chambers to decrease a torque imbalance in an engine. In one example, a method for operation of an engine includes determining a variation between compression ratios in a first combustion chamber and a second combustion chamber and operating a piston heating system to apply a targeted amount of heat to a first piston assembly based on the variation between the compression ratios, the first piston assembly including a first piston positioned within the first combustion chamber.