An engine assembly includes: a two-stroke internal combustion engine; a turbocharger operatively connected to the engine, the turbocharger having a compressor and an exhaust turbine; an intake pipe fluidly connected to the engine and to the compressor of the turbocharger; an exhaust tuned pipe fluidly connected to the engine and to the exhaust turbine of the turbocharger; a temperature sensor configured to generate a signal representative of a temperature of exhaust gas flowing within the exhaust tuned pipe; and a controller. The controller is configured to: determine a boost target pressure of the turbocharger based in part on the signal generated by the temperature sensor; and control the turbocharger to provide the boost target pressure to the engine. Methods for controlling an engine are also provided.

Disclosed herein is a method and an insert device for an internal combustion engine including: a central exhaust passage; a first expansion chamber in an upstream portion of the exhaust system and in fluidic communication with the central exhaust passage; a second expansion chamber in a downstream portion of the exhaust system and in fluidic communication with the central exhaust passage and the first expansion chamber, forming a continuous expansion chamber throughout a length of the insert device.

Disclosed herein is a method and an insert device for an internal combustion engine including: a central exhaust passage; a first expansion chamber in an upstream portion of the exhaust system and in fluidic communication with the central exhaust passage; a second expansion chamber in a downstream portion of the exhaust system and in fluidic communication with the central exhaust passage and the first expansion chamber, forming a continuous expansion chamber throughout a length of the insert device.

A configuration for a uniflow-scavenged, opposed-piston engine reduces exhaust cross-talk caused by mass flow between cylinders resulting from one cylinder having an open exhaust port during scavenging and/or charging while an adjacent cylinder is undergoing blowdown. Some configurations include a wall or other barrier feature between cylinders that are adjacent to each other and fire one after the other. Additionally, or alternatively, some engine configurations include cylinders with intake and exhaust ports sized so that there is an overlap in crank angle of two or more cylinders having open exhaust ports of about 65 crank angle degrees or less.

An exhaust system includes a housing comprising a first housing portion and a second housing portion separated by a common wall. The first housing portion has a first exhaust passage therethrough. The first exhaust passage has a first inlet receiving exhaust gasses from a turbocharger. The second housing portion has a second exhaust passage therethrough. The second exhaust passage has a second inlet receiving gasses from an exhaust bypass valve. The first passage and the second passage are non-intersecting within the housing.

An exhaust gas diverter valve coupled within a pipe comprises a housing having a passage therethrough, a valve member rotatably coupled within the housing the valve member rotates about a valve axis. A first valve seat mat be disposed partially circumferentially within said passage and extending radially inwardly.

A system and method for a variable displacement internal combustion engine using different types of pneumatic cylinder springs on skipped working cycles to control engine and aftertreatment system temperatures are described. The system and method may be used to rapidly heat up the aftertreatment system(s) and/or an engine block of the engine following a cold start by using one or more different types of pneumatic cylinder springs during skipped firing opportunities. By rapidly heating the aftertreatment system(s) and/or engine block, noxious emissions such as hydrocarbons, carbon monoxide, NO.sub.x and/or particulates, following cold starts are significantly reduced.

An exhaust after-treatment system includes a first set of exhaust after-treatment components, a second set of exhaust after-treatment components, an inlet to the exhaust after-treatment system, an outlet from the exhaust after-treatment system, and a valve and conduit arrangement configurable in a plurality of modes, in a first mode, exhaust gas entering the inlet flows through the second set of exhaust after-treatment components, then through the first set of exhaust after-treatment components, and then through the outlet. In a second mode, exhaust gas entering the inlet flows through the second set of exhaust after-treatment components without flowing through the first set of exhaust after-treatment components, and then through the outlet in a third mode, exhaust gas entering the inlet flows through the first set of exhaust after-treatment components, then through the second set of exhaust after-treatment components, and then through the outlet.

A four stroke internal combustion engine is disclosed comprising at least one cylinder arrangement, an exhaust conduit, and at least one turbine. The cylinder arrangement comprises an exhaust port arrangement configured to open and close an exhaust flow area, A.sub.CYL. The cylinder arrangement has a maximum volume, V.sub.MAX. The exhaust conduit extends between the exhaust flow area, A.sub.CYL, and a turbine wheel inlet area, A.sub.TIN, of the turbine and has an exhaust conduit volume, V.sub.EXH that is ≤0.5 times the maximum volume, V.sub.MAX. The exhaust port arrangement is configured to expose the exhaust flow area, A.sub.CYL, at a size of at least 0.22 times the maximum volume, V.sub.MAX, when a piston of the cylinder arrangement is at the bottom dead centre, BDC.

A four stroke internal combustion engine is disclosed comprising at least one cylinder arrangement, an exhaust conduit, and at least one turbine. The cylinder arrangement comprises an exhaust port arrangement configured to open and close an exhaust flow area, A.sub.CYL. The cylinder arrangement has a maximum volume, V.sub.MAX. The exhaust conduit extends between the exhaust flow area, A.sub.CYL, and a turbine wheel inlet area, A.sub.TIN, of the turbine and has an exhaust conduit volume, V.sub.EXH that is ≤0.5 times the maximum volume, V.sub.MAX. The exhaust port arrangement is configured to expose the exhaust flow area, A.sub.CYL, at a size of at least 0.22 times the maximum volume, V.sub.MAX, when a piston of the cylinder arrangement is at the bottom dead centre, BDC.