A compression ignition internal combustion engine includes: a cylinder block and a cylinder head; a piston including a cavity that defines a combustion chamber in cooperation with the cylinder block and the cylinder head; and a nozzle for injecting fuel into the combustion chamber.

An internal combustion engine for a motor vehicle has at least one cylinder, a cylinder head, and a piston which is movably mounted in the cylinder and has a combustion chamber side which delimits a combustion chamber with the cylinder head and the cylinder. The cylinder head has a combustion chamber roof, in which at least two valve seats for at least one inlet valve and at least one outlet valve are provided. The combustion chamber roof has at least one arched cylinder head section which is arranged between the at least two valve seats and points away from the combustion chamber.

An internal combustion engine for a motor vehicle has at least one cylinder, a cylinder head, and a piston which is movably mounted in the cylinder and has a combustion chamber side which delimits a combustion chamber with the cylinder head and the cylinder. The cylinder head has a combustion chamber roof, in which at least two valve seats for at least one inlet valve and at least one outlet valve are provided. The combustion chamber roof has at least one arched cylinder head section which is arranged between the at least two valve seats and points away from the combustion chamber.

A compression-ignited, opposed-piston engine equipped for multi-fuel operation includes at least one cylinder, a pair of pistons slidably disposed in the cylinder for opposing movement between respective bottom and fop center locations, and spaced-apart intake and exhaust ports near respective ends of the cylinder. The pistons include end surfaces constructed to form a shaped combustion chamber when the pistons are near top center locations during a compression stroke of the engine. At least one gaseous fuel injector communicates with the bore of the cylinder through an injector site in the cylinder between the intake port and the exhaust port. At least one liquid fuel injector communicates with the bore through an injector site in the cylinder. A fuel injection system coupled to the at least one gaseous fuel injector and to the at least one liquid fuel injector is operable to cause the at least one gaseous fuel injector to inject a main charge of gaseous fuel when the pistons are between the bottom and top center locations and to cause the at least one liquid fuel injector to inject a pilot charge of liquid fuel.

A combustion chamber for an opposed-piston engine has a rotationally skewed shape in a longitudinal section that is orthogonal to a chamber centerline, between diametrically-opposed openings of the combustion chamber through which fuel is injected. The rotationally skewed shape interacts with swirl to generate a tumble bulk charge air motion structure that increases turbulence.

An opposed piston engine includes approximately spherical combustion chamber formed by the two opposed pistons in a single cylinder and an intake manifold including gas hooks. The combustion chamber has a small cone shaped extension on each side leading to each of two opposed injectors located in the cylinder wall where the two pistons meet at the top of their stroke. The combustion chamber configuration reduces the surface area of the chamber and increases the burn length by a significant amount compared to known designs. The gas hooks in the intake manifold restrict the flow of exhaust gases into the intake manifold long enough for the pressure in the cylinder to blow down and the exhaust gasses to attain high velocity passing out through the exhaust manifold, allowing the intake ports to be uncovered before the exhaust ports.

In certain embodiments, a two-stage precombustion chamber may be used to reduce engine NOx levels, with fueled precombustion chambers, while maintaining comparable engine power output and thermal efficiency. One or more fuel admission points may be located in either the first prechamber stage or the second prechamber stage. A more efficient overall combustion characterized by low levels of NOx formation may be achieved by a two-stage precombustion chamber system while generating very high energy flame jets emerging from the second prechamber stage into the main combustion chamber. A first prechamber stage may be substantially smaller than a second prechamber stage. The volumes and aspect ratios of the two prechamber stages, along with the location of the electrodes within the first stage prechamber, the holes patterns, angles and the separate fueling, may be selected to create a distribution of fuel concentration that is substantially higher in the first stage prechamber compared to the second prechamber stage.

An opposed piston engine includes approximately spherical combustion chamber formed by the two opposed pistons in a single cylinder and an intake manifold including gas hooks. The combustion chamber has a small cone shaped extension on each side leading to each of two opposed injectors located in the cylinder wall where the two pistons meet at the top of their stroke. The combustion chamber configuration reduces the surface area of the chamber and increases the burn length by a significant amount compared to known designs. The gas hooks in the intake manifold restrict the flow of exhaust gases into the intake manifold long enough for the pressure in the cylinder to blow down and the exhaust gasses to attain high velocity passing out through the exhaust manifold, allowing the intake ports to be uncovered before the exhaust ports.

A diesel engine includes a cylinder block having a cylinder cavity defined therein. A cylinder head is coupled to the cylinder block and includes a lower semi-hemispherical surface defined thereon that defines an upper boundary of a combustion chamber. The engine includes a piston slideably disposed within the cylinder cavity that includes a piston crown having an upper surface configured to define a first portion of a lower boundary of the combustion chamber. The upper surface of the piston crown includes an axi-symmetric semi-hemispherical shape configured to correspond to the lower semi-hemispherical surface of the cylinder head.

The disclosure describes multipoint ignition systems for an engine and methods of operation of the same. The systems and methods can include an engine, including an engine block having at least one cylinder bore, a piston having a piston crown facing a flame deck surface such that a combustion main chamber is defined within a cylinder bore and located between the piston crown and the flame deck surface, the piston crown further including a piston bowl having a generally concave shape, and a combustion pre-chamber having a nozzle tip disposed in fluid communication with the combustion main chamber, the nozzle tip having at least one nozzle opening configured to inject a fuel jet into the combustion main chamber, wherein the piston includes a piston wall located around a circumference of the piston bowl, the piston wall including at least one cavity.