This method of gas exchange for four-stroke piston internal combustion engine comprising gas exchange through an intake and an exhaust valves and includes gas exchange through a piston-controlled port in a cylinder sleeve: exhausting combustion products through the port at the end of the power stroke and at the beginning of the exhaust stroke, removal of exhaust gases from the port (from the space outside the port, outside the cylinder) and air supply to the port (supply into afore-mentioned space). As a result, the combustion products do not return to the cylinder through the port at the end of the intake stroke and at the beginning of the compression stroke. This effect is combined with air intaking into the cylinder through the port at the end of the intake stroke and at the beginning of the compression stroke.

A uniflow engine includes a cylinder having a cylinder wall, an inlet channel, an extension of a central axis of the inlet channel first intersecting the cylinder wail in a first portion of the cylinder and next intersecting the cylinder wail in a second portion of the cylinder opposite the first portion of the cylinder, an intake air gallery, the intake air gallery having a gallery wall and being in flow communication with the inlet channel, and a plurality of intake ports extending between the cylinder wail and the gallery wall, at least some of the intake ports having different areas at the cylinder wall measured perpendicular to longitudinal axes of the intake ports, and wherein an area of at least one in take port in the first portion of the cylinder is larger than an area of at least one intake port in the second portion of the cylinder.

A uniflow engine includes a cylinder having a cylinder wall, an inlet channel, an extension of a central axis of the inlet channel first intersecting the cylinder wail in a first portion of the cylinder and next intersecting the cylinder wail in a second portion of the cylinder opposite the first portion of the cylinder, an intake air gallery, the intake air gallery having a gallery wall and being in flow communication with the inlet channel, and a plurality of intake ports extending between the cylinder wail and the gallery wall, at least some of the intake ports having different areas at the cylinder wall measured perpendicular to longitudinal axes of the intake ports, and wherein an area of at least one in take port in the first portion of the cylinder is larger than an area of at least one intake port in the second portion of the cylinder.

A fuel valve includes a housing, a nozzle with nozzle holes opening to a volume inside the nozzle at the front end of the housing, a gaseous fuel inlet port in the housing connected to high pressure gaseous fuel, an axially displaceable valve needle received in a longitudinal bore in the housing, and rests on a valve seat in a closed position and has lift from the valve seat in an open position, the valve seat placed between a fuel chamber and an outlet port, the fuel chamber connected to the fuel inlet port, the outlet port connected to the volume in the nozzle, an actuator system for moving the needle between the closed and open positions, an ignition liquid inlet port connected to high pressure ignition liquid, and conduit connecting the ignition liquid inlet port to the fuel chamber, the conduit including a fixed flow restriction.

A uniflow scavenging 2-cycle engine includes a cylinder inside which a combustion chamber is formed; a piston which slides within the cylinder; a scavenge port which is provided on one end side in a stroke direction of the piston in the cylinder to suck an active gas into the combustion chamber in accordance with the sliding movement of the piston; and a fuel injection unit which has an injection port located on the outside of the cylinder, and injects the fuel gas into the active gas sucked into the scavenge port.

A uniflow scavenging 2-cycle engine includes a cylinder inside which a combustion chamber is formed; a piston which slides within the cylinder; a scavenge port which is provided on one end side in a stroke direction of the piston in the cylinder to suck an active gas into the combustion chamber in accordance with the sliding movement of the piston; and a fuel injection unit which has an injection port located on the outside of the cylinder, and injects the fuel gas into the active gas sucked into the scavenge port.

A method which develops a supercritical combustion chamber environment and combines fumigation and water conversion to superheated steam to effect greater fuel efficiency and reduce exhaust gas pollutants from a compression ignition engine. The invention utilizes the fumigant method by combining two gases (DME and heptane) which autoignite prior to the injection of the liquid water. This pre-combustion of the fumigant gases combined with the engine's compression of the combustion chamber gases is managed to attain a supercritical combustion chamber environment into which the liquid water is injected. This targeted supercritical combustion chamber environment causes the water to become a superheated steam, resulting in significantly greater efficiency and negligible exhaust gas pollutants resulting from the steam engine.

A fuel system for an engine has a cylinder with an inlet air port, an air box surrounding the inlet air port, and a gaseous fuel injector positioned in the air box and having a nozzle located at the inlet air port. The fuel system also has a gaseous fuel control valve, a fuel supply line fluidly extending from the gaseous fuel control valve to the gaseous fuel injector, a purge valve, and a purge fluid supply line fluidly extending from the purge valve to at least one of the fuel supply line and the gaseous fuel injector. The fuel system also has a return valve and a return line fluidly extending from at least one of the fuel supply line and the gaseous fuel injector.

A uniflow-scavenging-type two-cycle engine includes: a cylinder; a piston that slides in the cylinder; an exhaust port that is provided at a first end of the cylinder; an exhaust valve that opens and closes the exhaust port; a scavenging port that is provided in an inner circumferential surface of a second end of the cylinder in the stroke direction of the piston and inhales an active gas into a combustion chamber in accordance with a sliding movement of the piston; a plurality of fuel injection valves that inject a fuel gas to the active gas, which has been drawn in from the scavenging port to the combustion chamber, to thereby generate a premixed gas; and a fuel injection control unit that varies injection directions of fuel gas injected from a part or all of the fuel injection valves.

A uniflow-scavenging-type two-cycle engine includes: a cylinder; a piston that slides in the cylinder; an exhaust port that is provided at a first end of the cylinder; an exhaust valve that opens and closes the exhaust port; a scavenging port that is provided in an inner circumferential surface of a second end of the cylinder in the stroke direction of the piston and inhales an active gas into a combustion chamber in accordance with a sliding movement of the piston; a plurality of fuel injection valves that inject a fuel gas to the active gas, which has been drawn in from the scavenging port to the combustion chamber, to thereby generate a premixed gas; and a fuel injection control unit that varies injection directions of fuel gas injected from a part or all of the fuel injection valves.