This invention has two main embodiments. An opposed piston 2-stroke axial engine and a 4-stroke axial engine. The opposed piston two stroke also offers an option of a novel cylinder deactivation design. Both, two stroke and four stroke engines share novel systems for coupling piston reciprocation to shaft rotation, piston and piston ring lubricant distribution, and provision for reacting out piston side load with minimum mechanical friction

An opposed piston engine has a driveshaft with at least one combustion cylinder positioned between opposing, curvilinear shaped cams mounted on the driveshaft, where the center axis of the combustion cylinder is parallel with but spaced apart from the driveshaft axis. A piston assembly is disposed in each end of the cylinder, with one piston assembly engaging one cam and the other piston assembly engaging the other cam. Each piston assembly includes a cam follower that can move along a curvilinear shaped cam to reciprocate the piston assembly within the cylinder. The combustion cylinder includes an intake port in fluid communication with an annular intake channel formed in the engine block in which the cylinder is mounted, and an exhaust port in fluid communication with an annular exhaust channel formed in the engine block.

An engine unit controller (EUC) in connection with a hybrid opposed piston engine can receive real-time movement data of a crankshaft via a crank position sensor. It can simultaneously receive current data of an electric motor that partially controls the crankshaft. With the known engine constants, the EUC can determine instantaneous combustion pressure data based on the movement data and the current data. Such combustion pressure data can be used to optimize the engine's performance in real-time.

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.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, and a second piston reciprocatingly disposed in a second cylinder. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of at least one of the first piston and the second piston. A combustion chamber may be fluidly coupled with the first cylinder and the second cylinder. An ignition source may be 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.

In an opposed-piston engine, a piston has a top land. The piston top land has a non-cylindrical shape which affords more clearance with a piston bore to thrust and anti-thrust sides than to front-facing and rear facing sides.

Various examples are provided related to opposing piston synchronized linear machines. In one example, among others, an opposed piston synchronized linear machine includes a linear engine having opposed piston assemblies including two pistons that move linearly in opposite directions along a longitudinal axis of a central cylinder; first and second linear electromagnetic machines coupled at a proximal end to the piston assemblies; and a resonant driver assembly that provides compression during a compression stroke of the linear engine. The first and second linear electromagnetic machines can convert linear motion provided by the two pistons to electrical energy in a generating mode. The opposed piston assemblies can be synchronously controlled to generate a compression ratio sufficient to combust fuel in a combustion chamber of the central cylinder.

An opposed-piston engine according to an embodiment is a first fuel injection device configured to inject fuel from a circumferential wall surface of at least one cylinder into the cylinder, and a second fuel injection device disposed to be displaced in a circumferential direction so as to be opposite to the first fuel injection device across an axial center of the cylinder. Each of the first fuel injection device and the second fuel injection device includes a plurality of injection holes having different injection directions, in a cross-section orthogonal to the axial direction. A direction directed by a first downstream injection hole is configured to pass through a second injection region, and a direction directed by a second downstream injection hole is configured to pass through a first injection region.

In an opposed-piston engine which includes a catalytic aftertreatment device in its exhaust system an exhaust gas condition indicating a catalyst temperature of the aftertreatment device is monitored. When the catalyst temperature is near or below a light-off temperature, a catalyst light-off procedure is executed to elevate the temperature of the catalyst.

Engines operating using multiple, different types of fuel are described. The engines may include components that control the introduction of fuels and/or reduce premature pre-ignition of fuels, such as a fuel comprising a percentage of hydrogen. The described hydrogen-fueled engines have a reduced carbon footprint.