A linear piston engine includes a housing having a combustion chamber located between opposing first and second piston chambers. A first piston assembly is located within the first piston chamber, and a second piston assembly is located within the second piston chamber. Each piston assembly includes a piston for reciprocating within the piston chamber. The piston is located adjacent to the combustion chamber. Each piston assembly also includes a crankshaft coupled to the piston for guiding the piston through a power stroke and a return stroke, and a linear output member coupled to the piston for providing a linear output motion based on reciprocating motion of the piston.

A hybrid drive system has two sources of driving power: a non-combustion drive system to provide mechanical torque and rotation to a driveshaft, and an opposed-piston, internal combustion engine configured to provide energy for the non-combustion drive system.

A hybrid drive system has two sources of driving power: a non-combustion drive system to provide mechanical torque and rotation to a driveshaft, and an opposed-piston, internal combustion engine configured to provide energy for the non-combustion drive system.

An engine placement configuration for a heavy-duty truck includes a chassis having two spaced-apart frame rails running in a longitudinal direction of the chassis, between front and rear ends, and a front wheel assembly with an axle attached to the frame rails. An opposed-piston engine is supported on the frame rails and positioned between the front end and the axle. The opposed-piston engine includes a cylinder assembly with a longitudinal axis disposed between the frame rails and oriented vertically with respect to the longitudinal direction. Alternatively, the opposed-piston engine includes a row of cylinders disposed between the rails and running in the longitudinal direction.

An engine placement configuration for a heavy-duty truck includes a chassis having two spaced-apart frame rails running in a longitudinal direction of the chassis, between front and rear ends, and a front wheel assembly with an axle attached to the frame rails. An opposed-piston engine is supported on the frame rails and positioned between the front end and the axle. The opposed-piston engine includes a cylinder assembly with a longitudinal axis disposed between the frame rails and oriented vertically with respect to the longitudinal direction. Alternatively, the opposed-piston engine includes a row of cylinders disposed between the rails and running in the longitudinal direction.

An opposed-piston engine includes a backlash reducing gear with at least a first and second gear that move relative to each other because of a hydraulic pressure applied within the gear. A backlash control system that includes the backlash reducing gear can dynamically adjust backlash between at least two gears in the gear train of the engine during operation of the engine instead of setting backlash prior to operation of the engine. A method for adjusting backlash in a two-stroke-cycle, opposed-piston engine with a backlash reducing gear includes providing hydraulic fluid, such as oil, to the gear, and allowing the backlash reducing gear to adapt to changes in the engine that include temperature changes, torque reversals, changes in load and the like. The backlash reducing gear adapts to changes in the engine by controlled leaking and intake of oil.

A transmission for an opposed-piston engine with two crankshafts includes a crankshaft gear train that combines the torque inputs from the two crankshafts and a gear arrangement coupled to the gear train that is operable to obtain various speed ratios for an output torque drive.

With reference to FIG. 2, the invention relates to an opposed stepped piston two-stroke engine comprising at least a first and a second cylinder, wherein the air piston is a stepped piston providing a first air transfer piston that expands and compresses a first air transfer volume to deliver air from the first air transfer volume to an air transfer system, and the exhaust piston is a stepped piston providing a second air transfer piston that expands and compresses a second air transfer volume to deliver air from the second air transfer volume to the air transfer system, each of the first and second air transfer volumes having an air inlet for receiving air; and wherein the air transfer system provides fluid connection between the respective first air transfer volume of each cylinder and the air port of another respective cylinder, via respective first air transfer conduits, and fluid connection between the respective second air transfer volume of each cylinder and the air port of the other respective cylinder, via respective second air transfer conduits, wherein the drive system is configured, for each cylinder, to have a predetermined phase angle such that one of the exhaust piston and air piston is driven before the other piston, causing delivery of air from its respective air transfer volume to the air transfer system before delivery of air occurs from the other of the air transfer volumes.

With reference to FIG. 2, the invention relates to an opposed stepped piston two-stroke engine comprising at least a first and a second cylinder, wherein the air piston is a stepped piston providing a first air transfer piston that expands and compresses a first air transfer volume to deliver air from the first air transfer volume to an air transfer system, and the exhaust piston is a stepped piston providing a second air transfer piston that expands and compresses a second air transfer volume to deliver air from the second air transfer volume to the air transfer system, each of the first and second air transfer volumes having an air inlet for receiving air; and wherein the air transfer system provides fluid connection between the respective first air transfer volume of each cylinder and the air port of another respective cylinder, via respective first air transfer conduits, and fluid connection between the respective second air transfer volume of each cylinder and the air port of the other respective cylinder, via respective second air transfer conduits, wherein the drive system is configured, for each cylinder, to have a predetermined phase angle such that one of the exhaust piston and air piston is driven before the other piston, causing delivery of air from its respective air transfer volume to the air transfer system before delivery of air occurs from the other of the air transfer volumes.

A piston crown for a piston of a pair of pistons in a two-stroke, opposed-piston, compression ignition combustion engine has a barrier layer and a conductive layer. The barrier layer at least partially surrounds a combustion chamber formed by the piston crown and an end surface of an opposing piston. The conductive layer connects the crown to the rest of the piston body. The barrier layer and the conductive layer are joined either through welding or through the fabrication process. Optionally, the piston crown includes an insulating layer between the barrier and conductive layers.