An opposed-piston engine that forms an inviscid layer between pistons and the respective cylinder walls. In an aspect, the opposed-piston engine utilizes a Scotch yoke assembly that includes rigidly connected opposed combustion pistons. In an aspect, the Scotch yoke assembly is configured to transfer power from the combustion pistons to a crankshaft assembly. In an aspect, the crankshaft assembly can be configured to have dual flywheels that are internal to the engine, and can be configured to assist with an exhaust system, a detonation system, and/or a lubrication system.

A dual crank mechanism is introduced for controlling and optimizing asymmetry in the motion profile of at least one piston of an opposed piston internal combustion (OPIC) engine piston pair. The dual crank mechanism produces a substantially asymmetrical non-sinusoidal, but periodic, reciprocating motion profile of the right-hand piston. A single crank mechanism is also introduced for controlling non-sinusoidal, but mostly symmetric, piston motion profile for one or both pistons of an opposed piston pair. The two novel crank mechanisms may be advantageously used exclusively or in combination in order to optimize the piston motion in a novel high efficiency OPIC engine having an externally mounted combustion chamber, an external compressing means for injecting compressed fuel mixtures directly into the external combustion chamber, and reducing cylinder porting to a single exhaust port per cylinder due to improved scavenging resulting from the asymmetric non-sinusoidal piston profiles produced by the novel crank mechanisms.

This invention relates to internal combustion engines and more particularly to internal combustion engines and methods of operating the engines with a new fuel saving cycle. Various embodiments use a passage between adjacent cylinders to enable a mode in which fuel combusted in one cylinder supplies pressure to the other that has not been supplied with fuel, thus enabling driving of both cylinders with less fuel.

An internal combustion engine, including a piston, a cylinder, and an output shaft, wherein the piston is arranged for reciprocating motion within the cylinder, driven by combustion, and the piston is coupled to the output shaft by a coupling such that said reciprocating motion of the piston drives rotation of the output shaft, wherein the engine further includes an oil pump arrangement having a multi-stage regulator.