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 system includes a reciprocating compressor for pressurizing a fluid medium and having a compressor cylinder for accommodating a compressor piston. The compressor cylinder has a main cylinder volume and a secondary adjustable volume in fluid communication with the main cylinder volume so as to provide a variable geometrical compression ratio.

An internal combustion engine system includes a reciprocating compressor for pressurizing a fluid medium and having a compressor cylinder for accommodating a compressor piston. The compressor cylinder has a main cylinder volume and a secondary adjustable volume in fluid communication with the main cylinder volume so as to provide a variable geometrical compression ratio.

An auto-ignition engine system is provided. The auto-ignition engine system includes a cylinder having an intake valve and an exhaust valve coupled thereto, an opening in a cylinder head defining a portion of the boundary of the cylinder, a glow plug heating element extending through the opening into the cylinder, an insert at least partially surrounding a glow plug heating element and coupled thereto, and an adjustment mechanism configured to alter the position of the glow plug heating element and the insert in the cylinder.

An auto-ignition engine system is provided. The auto-ignition engine system includes a cylinder having an intake valve and an exhaust valve coupled thereto, an opening in a cylinder head defining a portion of the boundary of the cylinder, a glow plug heating element extending through the opening into the cylinder, an insert at least partially surrounding a glow plug heating element and coupled thereto, and an adjustment mechanism configured to alter the position of the glow plug heating element and the insert in the cylinder.

An internal combustion engine system includes a reciprocating compressor for pressurizing a fluid medium and having a compressor cylinder for accommodating a compressor piston. The compressor cylinder has a main cylinder volume and a secondary adjustable volume in fluid communication with the main cylinder volume so as to provide a variable geometrical compression ratio.

A method and system for a hybrid opposed piston engine with dynamic controlling of the combustion volume and power output is provided. The method includes using a control system to control a phasing of opposed pistons for achieving a desired combustion volume during a combustion cycle. The control system can control an activation of an ignition of the hybrid opposed piston engine, such as to activate the ignition when a desired condition is present in the combustion chamber. Various embodiments of the hybrid opposed piston engine are further provided.

A variable compression device includes a piston rod, a first fluid chamber configured to move the piston rod in a direction in which a compression ratio is increased by supplying a pressurized working fluid thereto, a regulation member configured to regulate movement of the piston rod in a direction in which a compression ratio is increased, a second fluid chamber provided between the piston rod and the regulation member and configured to store the working fluid, a supply flow path configured to guide the working fluid supplied to the second fluid chamber, a discharge flow path configured to guide the working fluid discharged from the second fluid chamber, and a flow rate regulation unit provided in the discharge flow path and configured to regulate a flow of the working fluid when the piston rod approaches the regulation member.

The invention relates to a method for diagnosing and/or controlling a reciprocating engine having a variable compression ratio, wherein the method comprises the working steps: determining (S30) a first value (U.sub.1,1, U.sub.1,2; Δ.sub.1) of a rotational irregularity parameter of a crankshaft (1) of the reciprocating engine; and determining (S60) a value of a compression ratio parameter for the reciprocating engine based on said first rotational irregularity parameter value.

A length-adjustable connecting rod for a reciprocating piston machine, which may be a reciprocating piston internal combustion engine, is disclosed as well as a reciprocating piston machine and a vehicle. The connecting rod comprises a hydraulic length-adjusting device for adjusting an effective connecting rod length and a control device that can switch between two switching states, for controlling the length-adjusting device. The length-adjusting device comprises a hydraulic cylinder with a piston and a first hydraulic working chamber and a second hydraulic working chamber, the control device comprising a first valve and a second valve, the first valve of the control device being connected to the first hydraulic working chamber of the length-adjusting device in a fluid-communicating manner, and the second valve to the second hydraulic working chamber, the first valve and the second valve each being actuatable by means of a hydraulically actuatable adjusting piston that can axially move along an adjusting axis, the adjusting axis of the first valve being different from the adjusting axis of the second valve.