A piston is used for an engine including: an ignition plug disposed in the vicinity of a central axis of a cylinder; intake and exhaust ports disposed at positions where the ignition plug is interposed therebetween; and an injector disposed at a position offset from the ignition plug toward the intake port to inject fuel sprays toward a crown surface of the piston. The piston includes: a recess formed by recessing the crown surface of the piston with respect to other portions of the crown surface, in which the recess includes a step on an outer peripheral edge over the entire circumference thereof with respect to the other portions, and a pair of lateral sides formed straightly so as to extend substantially in parallel to a straight line connecting the injector and the ignition plug when seen in a direction of the cylinder axis.

A split cycle internal combustion engine comprising: a compression cylinder accommodating a compression piston configured to provide compressed working fluid; a combustion cylinder accommodating a combustion piston, wherein the combustion cylinder is coupled to the compression cylinder to receive compressed working fluid therefrom, and wherein the combustion cylinder comprises: (i) an inlet valve configured to control intake of compressed working fluid into the combustion cylinder, and (ii) an outlet valve configured to control exhausting of fluid from the combustion cylinder, and a controller configured to change the position during the engine cycle at which the inlet and/or outlet valves open to switch operation of the engine between an active mode and an engine braking mode, wherein the controller is configured to control at least one of: the inlet valve to open at a position which is closer to a bottom dead centre, BDC, position when operating in the engine braking mode than when operating in the active mode; and the outlet valve to open at a position which is closer to a top dead centre, TDC, position when operating in the engine braking mode than when operating in the active mode.

A piston for a diesel engine is prepared as a piston for a direct injection engine, a cavity face of the piston is grinded, and a squish face thereof is masked. Next, a high-purity aluminum coating is formed on the cavity face, and the masking of the squish face is removed and the entire area of the piston top face is subjected to an anodizing treatment. Thereafter, the cavity face is masked, and the squish face is subjected to a sealing treatment.

A control system for a spark-ignition internal combustion engine configured to produce tumble flow in a cylinder is provided. The spark-ignition internal combustion engine includes an ignition plug configured to ignite an air-fuel mixture in the cylinder. The control system includes a tumble flow rate controller configured to change a position of a vortex center of the tumble flow as viewed in a direction of a center axis of the cylinder, so as to control a flow rate of the tumble flow around the ignition plug at the ignition timing of the ignition plug.

A combustion chamber is provided within an internal combustion engine, the chamber bounded by a cylinder bore, a primary end, and a secondary end. The secondary end reciprocates between a TDC position nearest the primary end and a BDC position. Induction and exhaust ports are timed to open and close to transfer air into, and gasses from, the chamber. The chamber becomes fuel stratified when the secondary end is positioned within a stratified distance of the primary end. When stratified, the chamber is comprised of a central region, a perimeter region, and a transfer passageway between regions. A fuel injector at the primary end injects fuel only into the central region and only prior to ignition. The perimeter region pumps air into the central region prior to ignition, creating tumble turbulence. Combustion is initiated near TDC in the central region and concluded near TDC in the transfer passageway.

Methods and systems are provided for controlling spark plug fouling in newly manufactured vehicles. In one example, a method may include operating an engine with a first direct injection fueling strategy including single intake direct injection on an engine start when in a pre-delivery state, and transitioning to a second different direct injection fueling strategy including split direct injection on the engine start when in a post-delivery state. In this way, spark plug fouling may be avoided in newly manufactured vehicles.

A technique for fuel system protection for an internal combustion engine includes introducing a directly injected fuel into a combustion chamber through a direct fuel injector, introducing a fumigated fuel upstream of an intake valve, selectively operating the internal combustion engine with at least one of the directly injected fuel and the fumigated fuel, determining a temperature of the direct fuel injector as a first function of engine operating parameters, and performing a temperature mitigation technique when the temperature rises above a first predetermined value such that the temperature is maintained below a second predetermined value.

A fuel injection valve (6) is configured such that the effective opening area of an injection port (61) increases as its lift amount increases. A fuel injection control unit (an engine control unit 100) injects fuel in a lift amount changing mode wherein, when fuel is injected into a combustion chamber (17) in the terminal period of the compression stroke, the lift amount of the fuel injection valve is set to a predetermined large lift amount in the earlier period of the injection period, and in the later period of the injection period following the earlier period of the injection period, the lift amount is set to a small lift amount smaller than the large lift amount and is in a range where the fuel injection speed increases.

An internal combustion engine is described. Controlling the internal combustion engine includes gathering engine operating data during steady-state engine operation, including gathering a first dataset associated with a cylinder air charge during steady-state operation of the engine in the PVO state and gathering a second dataset associated with a cylinder air charge during steady-state operation of the engine in the NVO state. An optimization routine is executed to determine a first subset of parameters associated with a first relationship for a cylinder air charge model based upon the second dataset. The optimization routine is also executed to determine a second subset of parameters associated with a second relationship for the cylinder air charge model based upon the first dataset. A cylinder air charge is determined in real-time during engine operation based upon the cylinder air charge model and the first and second subsets of parameters.

A system for an internal combustion engine can include a separation device and an engine component including first and second valves. The separation device can separate intake air into a volume of nitrogen-rich air and a volume of oxygen-rich air. A first valve element can be movable relative to a first valve body and can have an annular shape disposed about a central axis of the combustion chamber. The first valve body can be fluidly coupled to the separation device and direct the oxygen-rich air into a central area of the combustion chamber. A second valve element can be movable relative to a second valve body and can have an annular shape disposed about the central axis, radially outward of the first valve. The second valve body can be fluidly coupled to the separation device and can direct the nitrogen-rich air to a peripheral area of the combustion chamber.