Abstract: Pressurized lubricating oil is accumulated in the bearings of opposed pistons and accumulated oil is dispensed therefrom for bearing lubrication and also for cooling the undercrowns of the pistons by jets of oil emitted from the bearings.

Abstract: The timing or phasing of port openings and closings during operation of an opposed-piston engine is varied in response to changing engine speeds and loads by changing crankshaft phasing.

Abstract: A combustion chamber for an opposed-piston engine is defined between a pair of pistons disposed for opposing reciprocal movement in a cylinder. The combustion chamber is formed between crowns of the pistons and has a radius that decreases from the longitudinal axis of the cylinder. Each crown includes a periphery, a bowl within the periphery defining a concave surface with a first portion curving inwardly toward the interior of the piston and a second portion curving outwardly from the interior, and a convex surface within the periphery curving outwardly and meeting the second portion of the concave surface to form a ridge. Each ridge has a height that decreases with the distance from a longitudinal axis.

Abstract: An opposed-piston engine includes pistons, each piston having an annular cavity in the piston's sidewall and positioned between its crown and ring grooves to block transfer of heat from the crown to the piston body.

Abstract: An air handling arrangement in a two-stroke cycle, opposed-piston engine with uniflow scavenging and constructed for heavy-duty operation includes sequentially arranged turbochargers in series with a supercharger, in some aspects, the air handling system is equipped with an EGR channel.

Abstract: In an opposed-piston engine, two or more fuel injectors are mounted to a cylinder for direct side injection into the cylinder. The injectors are controlled so as to inject either a single fuel pulse or a plurality of fuel pulses per cycle of engine operation in order to initiate combustion during varying engine speeds and operating conditions.

Abstract: Control of airflow in a uniflow-scavenged, two-stroke cycle, opposed-piston engine during transient operation includes monitoring at least one operating parameter of the engine to recognize a transition to a transient state of engine operation. If a transient state of operation is detected, fuel injection and airflow into to the cylinders of the engine are controlled to optimize combustion and limit emissions. Airflow into cylinders of the engine may be controlled by increasing a scavenging ratio of the engine or by increasing a trapping efficiency of the engine.

Abstract: A barrier ring for a cylinder assembly for an opposed-piston engine fits into a groove fashioned into a portion of the cylinder liner that is adjacent to the top dead center location of the end surfaces of the pistons, in a volume of the cylinder liner that defines the combustion chamber. The barrier ring and groove are part of a barrier assembly that prevents heat generated during combustion from reaching the outer wall of the cylinder assembly, reducing the need for conventional cooling systems and increasing the amount of heat retained in the combustion chamber. The barrier assembly allows for increased engine efficiency because of the combustion heat retained in the combustion chamber, as well as a reduction in the overall size of the engine because of the reduction in engine cooling needed.

Abstract: In ported engine constructions, cooling of piston crowns and cylinder liners results in reduction or elimination of bore/liner distortions, thus ensuring circularity of the bore/piston interface throughout engine operation. Consequently, the need for heavily-tensioned piston rings is eliminated. Such engine constructions incorporate annular low-tension compression seals on the pistons, which substantially reduce port bridge wear during all phases of engine operation while also limiting blow-by during combustion.

Abstract: 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.

Abstract: Exhaust temperature management strategies for an opposed-piston, two-stroke engine with EGR are based on control of a ratio of the mass of fresh air and external EGR delivered to a cylinder to the mass of the trapped charge (density of the delivered charge multiplied by the trapped volume at port closing).

Abstract: The air handling system of an opposed-piston engine is equipped with an externally-assisted pumping element such as an electrically-assisted compressor, an electrically-assisted supercharger, or an electrically-assisted turbocharger.

Abstract: On-board diagnostic monitoring of a two-stroke cycle, opposed-piston engine includes diagnostic monitoring of an air handling system equipped with a supercharger to determine whether the supercharger is functioning properly.

Abstract: A port opening edge shape for a port in a cylinder of an opposed-piston combustion engine is optimized for flow area, as well as for minimization of piston ring clipping. The port opening edge shape includes a top edge, a bottom edge, a first and second side edge connecting the top and bottom edge, and an apex in the top edge. The apex has the minimum radius of curvature of the port opening edge shape. A spline that defines the port opening edge shape can be calculated based upon a maximum height, a full width, an amount or degree of skew, and a minimum radius of curvature. A model can measure values for engine performance and determine which spline defines a port opening edge shape yields a desired engine performance.

Abstract: In an opposed-piston engine, two or more fuel injectors are mounted to a cylinder for direct side injection into the cylinder. The injectors are controlled so as to inject either a single fuel pulse or a plurality of fuel pulses per cycle of engine operation in order to initiate combustion during varying engine speeds and operating conditions.

Abstract: Control of fuel flow in a uniflow-scavenged, two-stroke cycle, opposed-piston engine includes limiting an amount of torque or fuel in response to a torque demand, based upon a comparison and a selection of fuel delivery options derived from a global airflow parameter and/or a trapped airflow parameter.

Abstract: A dual-crankshaft, opposed-piston, internal combustion engine includes one or more ported cylinders. Each cylinder has exhaust and intake ports, and the cylinders are juxtaposed and oriented with exhaust and intake ports mutually aligned. The crankshafts are rotatably mounted at respective exhaust and intake ends of the cylinders and are coupled by a multi-gear train. A pair of pistons is disposed for opposed sliding movement in the bore of each cylinder. All of the pistons controlling the exhaust ports are coupled by connecting rods to the crankshaft mounted near at the exhaust ends of the cylinders, and all of the pistons controlling the intake ports are coupled by connecting rods to the crankshaft mounted near at the intake ends of the cylinders. The crankshafts are connected by a timing belt operative to change the rotational timing between the crankshafts. The gear train support structure is stiffened to suppress gear train vibration.

Abstract: In an air handling system of an opposed-piston engine, mass airflow sensor operation is monitored by comparing mass airflow measured by the sensor with mass airflow through a supercharger.

Abstract: In ported engine constructions, cooling of piston crowns and cylinder liners results in reduction or elimination of bore/liner distortions, thus ensuring circularity of the bore/piston interface throughout engine operation. Consequently, the need for heavily-tensioned piston rings is eliminated. Such engine constructions incorporate annular low-tension compression seals on the pistons, which substantially reduce port bridge wear during all phases of engine operation while also limiting blow-by during combustion.

Abstract: A piston for an opposed-piston, internal combustion engine includes a crown with an end surface shaped to form a combustion chamber with an end surface of an opposing piston in the opposed-piston engine, a skirt part including a piston sidewall extending from the crown to an open end of the skirt part, a wristpin bore with first and second openings through the sidewall, a wristpin disposed in the wristpin bore, and at least two caps received in the first and second openings of the wristpin bore for sealing the wristpin bore and retaining the wristpin against axial movement.