Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.

A split cycle internal combustion engine comprising a compression cylinder accommodating a compression piston; a combustion cylinder accommodating a combustion piston; a crossover passage between the compression cylinder and the combustion cylinder arranged to provide working fluid to the combustion cylinder; a controller arranged to determine a peak temperature of combustion in the combustion cylinder based on a received indication of a peak temperature of combustion in the combustion cylinder; and a coolant system arranged to regulate a temperature of the working fluid supplied to the combustion cylinder; wherein, in response to determining that the peak temperature of combustion exceeds a selected threshold, the controller is configured to control the coolant system to regulate the temperature of the working fluid supplied to the combustion cylinder so that a peak temperature of combustion in the combustion cylinder is less than the selected threshold.

A control method for an internal combustion engine configured to implement fuel cut in response to becoming zero of an accelerator opening degree during travel of a vehicle, and generate an antiphase torque after the fuel cut by supplying fuel to a cylinder, in order to cancel out vibration of the vehicle caused due to the fuel cut includes setting a timing of generating the antiphase torque to be later than that for normal operation, in response to implementation of the fuel cut under high torque idle operation in which a torque of the internal combustion engine immediately before the fuel cut where the accelerator opening degree is zero is higher than that in the normal operation.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector and the main spark plug and the subspark plug. In a low-load range where an engine load is below a given reference load, the controller controls the main spark plug and the subspark plug so that the subignition is performed after performing the main ignition, and the controller retards the timing of the subignition in a high-speed range where an engine speed is above a given reference engine speed, compared with a low-speed range below the reference engine speed.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a controller electrically connected to the injector, the main spark plug and the subspark plug. When an engine speed is above a given reference engine speed, the controller controls, in a low-load range below a given reference load, the ignition devices so that the subignition is performed after the main ignition, and the controller controls, in a high-load range exceeding the reference load, the ignition devices so that only the subignition is performed, or so that the main ignition is performed at the same timing as or after the subignition.

An engine system is provided, which includes a cylinder block, a cylinder head, a piston, a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, and a control device. In a low-speed high-load range, a fuel injection timing is set in compression stroke and the main ignition and the subignition are performed after the fuel injection timing, and the fuel injection timing under a low-speed condition becomes later than that under a high-speed condition, and the ignition devices are controlled so that the subignition timing is retarded from the main ignition timing and an ignition phase difference that is the retard amount of the subignition timing becomes larger under the low-speed condition than under the high-speed condition.

An engine system is provided, which includes a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, a subspark plug that ignites the mixture gas inside the subchamber, an exhaust gas recirculation (EGR) device and a control device. In a specific range where EGR is performed, the ignition devices are controlled so that a subignition timing is retarded from a main ignition timing, and an ignition phase difference that is a retard amount of the subignition timing from the main ignition timing becomes larger under a high EGR condition than a low EGR condition, the EGR conditions being conditions in the specific range where engine speeds are the same and EGR rates are different, and the high EGR condition being larger in the EGR rate than the low EGR condition.

A method of manufacturing an internal combustion engine is provided. The engine includes a cylinder forming member, a piston reciprocatably accommodated in a cylinder, an injector which supplies fuel into a combustion chamber, and a heat insulating layer covering at least a part of a combustion-chamber wall surface and having a lower heat conductivity than the combustion-chamber wall surface. The method includes applying a coating material that is a material of the heat insulating layer to the combustion-chamber wall surface, assembling the piston to the cylinder forming member while the coating material is uncured, and heating the coating material to be cured by combusting the fuel injected from the injector and reciprocating the piston. The heating the coating material includes injecting the fuel from the injector at least in an early stage of the heating so that the injected fuel adhering to the surface of the coating material is suppressed.

Methods and systems are provided for re-combustion of exhaust in a cylinder of a multi-cylinder engine in order to increase the temperature of the exhaust for enhancing catalytic conversion within the multi-cylinder engine. In one example, a method may include expelling combusted gases from the cylinder into an intake manifold via an intake valve during an exhaust stroke, in order to rebreathe in the combusted gases from the intake manifold via the intake valve in a subsequent intake stroke.

An injection control device includes: an instruction output unit outputting an instruction energization time that is an instruction value of an energization time of a fuel injection valve corresponding to a target injection amount; an energization controller controlling energization of the fuel injection valve based on the instruction energization time; an area corrector correcting an area of an electric current flowing through the fuel injection valve when the fuel injection valve is driven by the electric current, calculating a correction time of the energization time, and correcting the instruction energization time; an abnormality determiner determining that an abnormality related to the area correction has occurred when the correction time reaches a predetermined upper limit value; and a normal-return determiner executing, after the abnormality determiner determines that the abnormality related to the area correction has occurred, a normal-return determination at an execution timing of when a degree of influence of the abnormality on an emission becomes equal to or less than a predetermined value, for determining whether or not an abnormal state in which the abnormality related to the area correction has been caused has returned to a normal state.