A method for controlling an internal combustion engine system, the engine system including a combustor arranged to receive air and fuel, and combust the received air and fuel, an expander arranged to expand exhaust gases from the combustion in the combustor and to extract energy from the expanded exhaust gases, and a communication valve arranged to control a communication between the combustor and the expander, including determining during operation of the engine system whether there is a pressure difference across said communication valve.

The present invention relates to an internal combustion engine arrangement for a vehicle, said internal combustion engine arrangement comprising a combustion cylinder housing a reciprocating combustion piston, and an expansion cylinder housing a reciprocating expansion piston, said expansion cylinder being arranged in downstream fluid communication with the combustion cylinder for receiving combustion gases exhausted from the combustion cylinder, wherein the internal combustion engine arrangement further comprises a pressure tank arranged in fluid communication with the expansion cylinder, wherein the internal combustion engine arrangement is further arranged to be operated in a first operating mode in which compressed gas generated in the expansion cylinder is delivered to the pressure tank, and a second operating mode in which compressed gas contained in the pressure tank is delivered from the pressure tank to the expansion cylinder.

An internal combustion engine includes first and second power cylinders and an expander cylinder, and is configured to operate in an expander mode and a bypass mode by selectively fluidly coupling exhaust flow from the first and second power cylinders to the expander cylinder. Operation includes commanding a transition from the bypass mode to the expander mode, including retarding openings of intake valves of the first and second power cylinders to a LIVC position. Exhaust valves of the power cylinders are controlled to effect fluid flow to the expander cylinder, and opening of an outlet valve of the expander cylinder is controlled to a maximum advanced state. The openings of the intake valves of the first and second power cylinders are controlled to desired positions associated with engine operation in the expander mode.

An internal combustion engine includes first and second power cylinders and an expander cylinder, and is configured to operate in an expander mode and a bypass mode by selectively fluidly coupling exhaust flow from the first and second power cylinders to the expander cylinder. Operation includes commanding a transition from the bypass mode to the expander mode, including retarding openings of intake valves of the first and second power cylinders to a LIVC position. Exhaust valves of the power cylinders are controlled to effect fluid flow to the expander cylinder, and opening of an outlet valve of the expander cylinder is controlled to a maximum advanced state. The openings of the intake valves of the first and second power cylinders are controlled to desired positions associated with engine operation in the expander mode.

A split-cycle engine includes a compression cylinder having a first volume for a first working fluid and a second volume for a second working fluid, the first volume and second volume being separated by the compression piston, an expansion cylinder having a first volume for the first working fluid and a second volume for the second working fluid, the first volume and second volume being separated by the expansion piston, and a fluid coupling between the second volume of the compression cylinder and the second volume of the expansion cylinder, wherein the two second volumes and the fluid coupling provide a closed volume for the second working fluid, wherein the fluid coupling includes a regenerator arranged such that the two second volumes are thermally decoupled.

A split-cycle engine includes a compression cylinder having a first volume for a first working fluid and a second volume for a second working fluid, the first volume and second volume being separated by the compression piston, an expansion cylinder having a first volume for the first working fluid and a second volume for the second working fluid, the first volume and second volume being separated by the expansion piston, and a fluid coupling between the second volume of the compression cylinder and the second volume of the expansion cylinder, wherein the two second volumes and the fluid coupling provide a closed volume for the second working fluid, wherein the fluid coupling includes a regenerator arranged such that the two second volumes are thermally decoupled.

An engine includes an engine housing defining a pair of cylinders, a pair of ignitor cylinders and a crankcase, a pair of cylinder heads connected to the engine housing and enclosing the pair of cylinders, a pair of spark plugs connected to the pair of cylinder heads and in communication with the pair of cylinders, a piston assembly in communication with the pair of cylinders, a rocker arm connected to the piston assembly, a connecting rod connected to the rocker arm, and a drive shaft disposed within the crankcase and connected to the connecting rod, a pair of ignitor cylinder plugs fit within the pair of ignitor cylinders, ignitor piston rod apertures formed though the engine housing, and rod aperture plugs fit within the piston rod apertures.

A highly-efficient, yet simply constructed internal combustion engine includes an intake cylinder to accommodate intake and pre-compression of an oxidizing agent, a combustion cylinder to accommodate a further compression of the oxidizing agent, an injection and ignition of fuel, and a partial expansion of combustion gases produced by the ignition of fuel; and an exhaust cylinder to accommodate a further expansion of the combustion gases and subsequent exhausting of the further expanded combustion gases. A reciprocating piston is inside each of the intake, combustion and exhaust cylinders and a crankshaft is coupled to the reciprocating pistons. A first transfer passage facilitates flow of the pre-compressed oxidizing agent from the intake cylinder to the combustion cylinder and a second transfer passage facilitates flow of the partially-expanded combustion gases from the combustion cylinder to the exhaust cylinder.

A highly-efficient, yet simply constructed internal combustion engine includes an intake cylinder to accommodate intake and pre-compression of an oxidizing agent, a combustion cylinder to accommodate a further compression of the oxidizing agent, an injection and ignition of fuel, and a partial expansion of combustion gases produced by the ignition of fuel; and an exhaust cylinder to accommodate a further expansion of the combustion gases and subsequent exhausting of the further expanded combustion gases. A reciprocating piston is inside each of the intake, combustion and exhaust cylinders and a crankshaft is coupled to the reciprocating pistons. A first transfer passage facilitates flow of the pre-compressed oxidizing agent from the intake cylinder to the combustion cylinder and a second transfer passage facilitates flow of the partially-expanded combustion gases from the combustion cylinder to the exhaust cylinder.

A piston compound internal combustion engine is disclosed with an expander piston deactivation feature. A piston internal combustion engine is compounded with a secondary expander piston, where the expander piston extracts energy from the exhaust gases being expelled from the primary power pistons. The secondary expander piston can be deactivated and immobilized, or its stroke can be reduced, under low load conditions in order to reduce parasitic losses and over-expansion. Two mechanizations are disclosed for the secondary expander piston's coupling with the power pistons and crankshaft. Control strategies for activation and deactivation of the secondary expander piston are also disclosed. In addition, six-cylinder engine configurations are defined by replicating groups of two power pistons and one expander piston.