Abstract: A multi-pass catalytic converter can divide a catalyst block into several catalytic volumes and enable the exhaust gas to flow through each volume in two or more passes consecutively. As the exhaust gas in an early pass can emit sensible thermal energy and chemical reaction energy to preheat the remaining catalytic volumes via conductive heat transfer, it can shorten the catalyst light-off time for the later passes and the whole catalyst block. By recouping the previously lost dissipating heat from the early catalytic volume, the present disclosure can significantly reduce the catalyst light-off time and emission concentration. Furthermore, one or more mixing chambers can be utilized to thoroughly mix the exhaust gas.

Abstract: A novel two-stroke opposed piston engine with sleeve valves and T-scavenging breathing is provided. The two-stroke opposed piston engine has a unique uni-flow scavenging breathing that can deliver higher power density than the traditional uniflow-scavenging two-stroke opposed piston engine. Furthermore, a method of operating a two-stroke opposed piston engine is provided. The novel opposed piston engine can be a hybrid engine with one or more electric machines.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A hybrid opposed piston engine is described that can include a cylindrical chamber and first and second pistons slidably disposed in the cylindrical chamber, surfaces of the first and second pistons and walls of the cylindrical chamber defining an internal combustion volume. The hybrid opposed piston engine can also include at least one port in the cylindrical chamber to allow air and fuel into and exhaust gas out of the internal combustion volume. In some embodiments, the hybrid opposed piston engine includes a drive shaft including a first mechanical linkage between the first piston and a crankshaft that is configured to move the first piston within the cylindrical chamber. In some embodiments, the hybrid opposed piston engine includes an electrical component adjacent to the second piston, the electrical component configured to move the second piston within the cylindrical chamber.

Abstract: An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

Abstract: An internal combustion engine can include a piston moving in a cylinder and a junk head disposed opposite the piston head in the cylinder. The junk head can optionally be moveable between a higher compression ratio position closer to a top dead center of the piston and a lower compression ratio position further from the top dead center position of the piston. At least one intake port can deliver a fluid comprising inlet air to a combustion chamber within the cylinder. Combustion gases can be directed out of the combustion volume through at least one exhaust port. One or both of the intake port and the exhaust port can be opened and closed by operation of a sleeve valve that at least partially encircles the piston. Related articles, systems, and methods are described.

Abstract: Energy to speed heating of a catalyst associated with an internal combustion engine can be provided in the form of sensible energy (heat) via hot combustion products. In some variations, timing of opening and/or closing of an exhaust valve can be manipulated to increase sensible heat delivered to the catalyst in the exhaust gases.

Abstract: Diesel opposed piston engines, optionally with variable compression ratio and/or turbocharging, can provide improved fuel efficiency by adapting a compression ratio of the engine in accordance with an engine load such that larger compression ratios are used for smaller loads and smaller compression ratios are used for larger loads. Turbocharging can provide improved efficiency at the smaller compression ratio operating conditions. Optionally, one or more current engine parameters can be modified to maintain a peak combustion chamber temperature below a threshold temperature at which an acceptable level of nitrogen oxide pollutants (NOX) is expected to be formed. One or more swirl inducing features can be included on piston crowns in an opposed piston engine. Methods, systems, articles of manufacture, etc. are described.

Abstract: An internal combustion engine is operable in an efficiency mode providing a first power output range between zero and a transition power output and in a power mode providing a second power output range between the transition power output and a maximum power output. The efficiency mode can include a first ignition timing and a first air/fuel ratio of the mixture to avoid premature auto-ignition, and the power mode can include a second ignition timing and a second air/fuel ratio of the mixture to avoid premature auto-ignition of the mixture. To further enable knock free operation of such an engine, turbulence can be imparted to the mixture to promote a faster burn duration and high temperatures that may lead to premature auto-ignition of the mixture can be avoided.

Abstract: Fuel efficiency of small carbureted engines can be improved through the use of a fuel shut off valve that ceases fuel flow in the carburetor upon determination that the engine throttle has been closed and the engine is not at or near an idle condition.

Abstract: Various embodiments of methods and systems for varying the compression ratio in opposed-piston engines are disclosed herein. In one embodiment, an opposed-piston engine can include a first phaser operably coupled to a first crankshaft and a second phaser operably coupled to a corresponding second crankshaft. The phase angle between the crankshafts can be changed to reduce or increase the compression ratio in the corresponding combustion chamber to optimize or at least improve engine performance under a given set of operating conditions.

Abstract: An internal combustion engine can include a combustion volume within a cylinder of an internal combustion engine. The combustion volume can be defined at least by a cylinder wall and a first piston in the cylinder. A swirl port can deliver a fluid into the combustion volume via a swirl port outlet such that the delivered fluid is directed around a periphery of the cylinder with a fluid velocity disposed at a predetermined angle away from tangential to a curve of the cylinder wall to generate a swirling motion in the combustion volume.

Abstract: An internal combustion engine can be operated in response to a received first throttle control input in a first operating regime that includes delivering a first air-fuel mixture having a first air/fuel ratio to a combustion volume to deliver a first output power in a first output power range between zero and a transition output power level. The engine can be operated in response to a received second throttle control input in a second operating regime that includes delivering a second air/fuel ratio richer than the first air/fuel ratio to the combustion volume to deliver a second output power in a second output power range between the transition output power level and a maximum output power level.

Abstract: A sleeve valve with a valve body that at least partially encircles at least one piston that moves in a reciprocating manner can, at least partially define with the at least one piston a combustion chamber of an internal combustion engine. A valve actuation mechanism can move the sleeve valve between an open position and a closed position to control flow through a port of the internal combustion engine. The sealing edge of the sleeve valve can be urged against a valve seat by an urging force generated by the valve actuation mechanism when the sleeve valve is moved to the closed position. At least one of the sleeve valve and the valve seat can include a valve assistance feature that assists the valve actuation mechanism in resisting forces generated by the internal combustion engine in opposition to the urging force. Related articles, systems, and methods are described.

Abstract: Various types of valve systems are disclosed herein. In one embodiment, a positive control reciprocating sleeve valve system for use with an internal combustion engine includes opening and closing rockers controlled by corresponding opening and closing cam lobes. In one aspect of this embodiment, interference can be designed into the valve control system to provide additional “hold-closed” force to hold the valve against its seat during a portion of the engine cycle. In another aspect of this embodiment, positive control valve systems can include compliant components and systems, hydraulic systems, pneumatic systems, and/or mechanical spring systems to control valve lash, facilitate sealing, etc.

Abstract: A sleeve valve assembly. The assembly includes a valve seat, a sleeve valve and an oil path-defining piece. The sleeve valve includes a distal end with a cavity. The distal end contacts the valve seat when the sleeve valve is located in a closed position. The oil path-defining piece includes an inlet port, an outlet port and a plurality of cooling passages. The flange of the sleeve valve is slidably in contact with the oil path-defining piece such that cooling fluid travelling into the inlet port and through the cooling passages enters into the cavity before exiting out the exit port.

Abstract: A catalyst associated with an internal combustion engine can be heated to improve emissions performance of the engine. Hydrogen can be generated within the internal combustion engine by combusting a first combustion mixture having a first air-fuel ratio including excess fuel relative to a stoichiometric air-fuel ratio, such that a reforming reaction occurs during the combusting of the first combustion mixture. A second combustion mixture having a second air-fuel ratio including excess oxygen can be combusted within the internal combustion engine such that oxygen remains in second exhaust gases after the combusting of the second combustion mixture. The first exhaust gases and the second exhaust gases can be delivered to the catalyst and the catalyst is heated by reacting at least some of the hydrogen and at least some of the oxygen at the catalyst. Internal combustion engines, systems, vehicles engine management systems, and method are disclosed.

Abstract: An internal combustion engine can be operated in response to a received first throttle control input in a first operating regime that includes delivering a first air-fuel mixture having a first air/fuel ratio to a combustion volume to deliver a first output power in a first output power range between zero and a transition output power level. The engine can be operated in response to a received second throttle control input in a second operating regime that includes delivering a second air/fuel ratio richer than the first air/fuel ratio to the combustion volume to deliver a second output power in a second output power range between the transition output power level and a maximum output power level. Related methods, systems, and article of manufacture are described.