An internal combustion engine and a method of controlling an internal combustion engine are provided, that are more efficient than existing engines. The internal combustion engine includes a combustion chamber, and the engine is configurable to operate in: a compressionless operating mode where the engine is driven by combustion of fuel and oxidant in the combustion chamber without compression of the fuel and oxidant; and a compression generating operating mode where the engine is used to compress fluid in the combustion chamber.

An internal combustion engine and a method of controlling an internal combustion engine are provided, that are more efficient than existing engines. The internal combustion engine includes a combustion chamber, and the engine is configurable to operate in: a compressionless operating mode where the engine is driven by combustion of fuel and oxidant in the combustion chamber without compression of the fuel and oxidant; and a compression generating operating mode where the engine is used to compress fluid in the combustion chamber.

An internal combustion engine includes a four-stroke combustion cylinder assembly configured for combustion of hydrogen gas within at least one combustion chamber of the combustion cylinder assembly such as to drive a crankshaft of the engine, an intake passage upstream of the cylinder assembly and an exhaust passage downstream of the cylinder assembly; a displacement compressor arranged within the intake passage, the displacement compressor being configured for compression of intake gas, an exhaust gas recirculation system configured for recirculating at least a portion of the exhaust from the exhaust passage to the displacement compressor.

An internal combustion engine includes a four-stroke combustion cylinder assembly configured for combustion of hydrogen gas within at least one combustion chamber of the combustion cylinder assembly such as to drive a crankshaft of the engine, an intake passage upstream of the cylinder assembly and an exhaust passage downstream of the cylinder assembly; a displacement compressor arranged within the intake passage, the displacement compressor being configured for compression of intake gas, an exhaust gas recirculation system configured for recirculating at least a portion of the exhaust from the exhaust passage to the displacement compressor.

Provided is a free piston generator based on a split thermodynamic cycle, which belongs to the technical field of power energy. The present disclosure solves the problem of low power generation efficiency of an existing free piston generator. The free piston generator includes a linear generator set and two internal combustion engine sets arranged at two ends of the linear generator set. Air is first subjected to first-stage compression by the low-pressure cylinder set in the internal combustion engine sets and is then subjected to second-stage compression in the high-pressure cylinders, so that the intake pressure of an internal combustion engine is effectively increased, which is favorable for increasing the average effective pressure in a work process, thereby improving the thermal efficiency and the power generation efficiency of the free piston generator. A combusted working medium is first subjected to first-stage expansion in the high-pressure cylinders and is then subjected to second-stage expansion in the low-pressure cylinders, which effectively increases the utilization rate of energy in exhaust gas, increases the expansion work, and further improves the thermal efficiency and the power generation efficiency of the free piston generator.

Improvements to an engine comprise an air compressor cylinder with a piston, a combustion chamber cylinder with a piston. An engine has added an expansion chamber cylinder with a piston. Pistons each have a connecting rod and connecting rod head and associated parts adapted for reciprocating motion via combustion products, and a transmission associated with the engine. Improvements are to the piston seals, ignition assembly, valve shape and stem/rocker, valve operating mechanism, construction of head, heat management/heat shield, connecting rod/piston rotator, engine balancing, fuel pump placement, and a machining process.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, a combustion chamber fluidly coupled with the first cylinder, and an ignition source at least partially disposed within the combustion chamber. An intake valve may provide selective fluid communication between an intake system and the combustion chamber, an exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. A second piston may be reciprocatingly disposed within a second cylinder, configured to draw a fluid into the second cylinder via a fluid inlet, and expel the fluid via a fluid outlet. A pressure accumulator may receive the fluid from the second cylinder and provide a reservoir of pressurized fluid. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of the first piston and the second piston.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, a combustion chamber fluidly coupled with the first cylinder, and an ignition source at least partially disposed within the combustion chamber. An intake valve may provide selective fluid communication between an intake system and the combustion chamber, and an exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. A second piston may be reciprocatingly disposed within a second cylinder. An inlet associated with the second cylinder may be fluidly coupled with the intake system, and an outlet may be fluidly coupled with one or more of the first cylinder and the combustion chamber. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of the first piston and the second piston.

A split cycle internal combustion engine includes a combustion cylinder accommodating a combustion piston and a compression cylinder accommodating a compression piston. The engine also includes a controller arranged to receive an indication of a parameter associated with the combustion cylinder and/or a fluid associated therewith and to control an exhaust valve of the combustion cylinder in dependence on the indicated parameter to cause the exhaust valve to close during the return stroke of the combustion piston, before the combustion piston has reached its top dead centre position (TDC), when the indicated parameter is less than a target value for the parameter; and close on completion of the return stroke of the combustion piston, as the combustion piston reaches its top dead centre position (TDC), when the indicated parameter is equal to or greater than the target value for the parameter.

The present invention relates to a method for controlling injection of a gaseous fuel, such as hydrogen or a hydrogen based gas, and a water-based fluid medium into a combustion engine. The method comprises the steps of: in a first operational mode injecting the gaseous fuel and optionally a water based fluid medium into a combustion chamber of the engine at a relatively high pressure; in a second operational mode injecting water as liquid into engine to reduce the temperature and pressure inside the combustion chamber, and injecting the gaseous fuel into the combustion chamber at a relatively low pressure.