Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

A method of controlling a rate of warm-up of an internal combustion engine fluidly connected to an exhaust system is disclosed. The method includes identifying a cold-start of the engine. The method also includes regulating, in response to the identified cold-start of the engine, an exhaust pressure modulation (EPM) valve arranged in a main exhaust passage of the exhaust system. The main exhaust passage channels engine exhaust gas to the ambient. Such regulation of the EPM valve will restrict a flow of the engine exhaust gas to the ambient and increase exhaust gas backpressure in the exhaust system up to a predetermined pressure value. Furthermore, the subject regulation of the EPM valve will increase a load on and the rate of warm-up of the engine. A vehicle having an engine and a controller programmed to control a rate of the engine's warm-up of according to the method is also disclosed.

A method for controlling an engine includes, with a fuel injector, injecting a quantity of fuel into a cylinder of the engine for combustion. The method further includes calculating a torsional power level for the cylinder in response to the combustion of the injected quantity of fuel, mapping the torsional power level to an injected fuel mass, and comparing the injected fuel mass to a reference fuel mass to determine a fuel mass offset. The engine may be controlled based on the determined fuel mass offset.

A method for operating an internal combustion engine includes operating at least one cylinder pre-chamber in a homogeneous charge compression ignition (HCCI) combustion mode by providing an air/fuel mixture in the pre-chamber that is fluidly connected to the at least one engine cylinder, creating H and OH radicals in the pre-chamber to achieve an ignition in the at least one pre-chamber, determining whether an ignition timing is advanced or delayed relative to a desired timing, and delaying the ignition when the ignition is advanced relative to the desired timing by cooling the pre-chamber and the at least one engine cylinder.

Main fuel injected from the fuel injector into the combustion chamber is made to auto-ignite. During the compression stroke after injection of the main fuel and before the auto-ignition of the main fuel, first auxiliary fuel and second auxiliary fuel are successively injected from the fuel injector. By controlling the injection timing of the first auxiliary fuel, the ignition timing of the spark plug, and the injection timing of the second auxiliary fuel, the first auxiliary fuel is made to burn by flame propagation combustion by the ignition action of the spark plug, the second auxiliary fuel is made to be injected inside the flame propagation combustion region, and the second auxiliary fuel is made to burn by diffusive combustion before auto-ignition of the main fuel occurs.

A control device of an engine is provided. The engine is operated at a high compression ratio, a geometric compression ratio of the engine being 14:1 or higher. The control device includes a fuel injection controller for controlling a fuel injector of the engine to start a fuel injection in a latter half of a compression stroke within an engine operating range where an engine speed is below a predetermined value and an engine load is above a predetermined value, and an ignition controller for controlling an ignition plug of the engine to retard an ignition timing when a timing for the fuel injection controller to start the fuel injection is on a retarding side of a predetermined timing, the ignition timing being retarded based on a retarding amount of the fuel injection start timing from the predetermined timing.

An engine control method includes a step of setting combustion mode in which a first combustion mode in which a mixed gas is combusted by propagating flame or a second combustion mode in which the mixed gas is combusted by self-ignition is selected, a step of setting air-fuel ratio mode in which a lean first air-fuel ratio mode or a second air-fuel ratio mode equal to or richer than a theoretical air-fuel ratio is selected, a step of setting torque reduction in which a torque reduction amount by which a torque generated by an engine is reduced based on a steer angle of a steering wheel, and a suppressing step in which reducing the torque generated by the engine based on the torque reduction amount set in the step of setting torque reduction is suppressed.

A control system includes a processor for controlling an internal combustion engine having a temperature region, wherein a change of ignition delay time accompanying a rise in a cylinder temperature when the cylinder temperature is in the temperature region is smaller than when the cylinder temperature is out of the temperature region. When a self ignition timing of secondary fuel is earlier than a self ignition timing of primary fuel due to the secondary fuel being injected at a crank angle at which the cylinder temperature is higher than the temperature region, the processor controls a ratio of the secondary fuel to be lower than when the self ignition timing of the secondary fuel is later than the self ignition timing of the primary fuel due to the secondary fuel being injected at a crank angle at which the cylinder temperature is within the temperature region.

Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

Methods and systems are provided for an auto-ignition internal combustion engine comprising an exhaust gas recirculation arrangement, an intake system, and an exhaust gas discharge system for the discharge of exhaust gases, in which the internal combustion engine is operable, at least in a first, stoichiometric operating mode, by way of a spatial ignition method (HCCI mode). For the aftertreatment of the exhaust gas in the first operating mode, a three-way catalytic converter is provided in the exhaust gas discharge system for reducing nitrogen oxides and oxidizing unburned hydrocarbons and carbon monoxide. In this way, the auto-ignition internal combustion engine has a greater window of operation in the HCCI mode than conventional auto-ignition internal combustion engines.