Abstract: An object of this invention is to provide a technology wherein a stratification of an EGR gas with an air-fuel mixture or a fresh air is achieved and capable of introducing the EGR gas in a large quantity, even when an engine load is high as an operation state of an internal combustion engine. With this invention, when a stratified combustion is performed by introducing the EGR gas, the fresh air is supercharged by a compressor, a fresh air blocking valve is closed to block inflow of the fresh air into a first intake port, and a variable valve mechanism opens a first intake valve before opening of a second intake valve, and, thereafter, opens the second intake valve.

Abstract: A method for dislodging exhaust gas deposits from an exhaust gas recirculation (EGR) cooler (26) associated with an engine includes the steps of providing at least one on-board gas source (S) for providing a gas (G) at a superatmospheric pressure, and placing the EGR cooler in fluid communication with the gas source through a supply conduit (44, 144). The supply conduit (44, 144) includes at least one valve (V) that is selectively operable to a closed condition closing the supply conduit and to an open position opening the supply conduit. The method also includes the step of operating the at least one valve (V) from the closed condition to the open condition to allow the superatmospheric gas (G) to flow through the supply conduit (44, 144) to the EGR cooler (26).

Abstract: A high flow EGR system for an internal combustion engine having a pair of series connected EGR coolers and a water droplet condensation collector and reservoir connected to the gas flow. The reservoir feeds a pump which is actuated to inject the liquid to the engine adjacent each cylinder for uniform distribution of the water to the engine cylinders. The pump is controlled to inject the water at appropriate conditions during the engine operating cycle.

Abstract: A method of controlling homogenous charge compression ignition (HCCI) combustion timing and pressure rise rate. A constant volume air pump, such as a supercharger, is equipped to provide a variable amount of fresh air to a turbocharger. The also turbocharger drives a high pressure exhaust gas recirculation (EGR) loop. The fresh air intake and the EGR ratio are independently controlled. This combination of hardware allows for good control of combustion timing by providing for EGR variations without undue effect from varying oxygen concentration. Additionally, by adjusting the EGR ratio, the pressure rise rate during combustion can be controlled to reduce combustion noise.

Abstract: A cooling circuit and an independent heat recovery circuit are associated with an internal combustion engine. A coolant is circulated a pump in a first and a second cooling sub-circuit. An increase in pressure in a work medium is achieved within the heat recovery circuit by a pump. This work medium is changed from liquid aggregate state to vaporous aggregate state and back to the liquid aggregate state in heat exchangers. This work medium is divided after the pump into two parallel partial flows and is changed into vaporous state in a first parallel branch in an EGR heat exchanger through which recycle exhaust gas flows and in a second parallel branch in an exhaust gas heat exchanger through flow exhaust gas downstream of the low-pressure turbine flows. This vaporous work medium is then fed to an expander and is then conducted through a cooled condenser and, liquefied again.

Abstract: The invention relates to a method for producing a carbon dioxide-rich gas mixture (44) wherein a hydrocarbon-containing fuel (21) is burned in a combustion chamber of a gas engine (10) in a gas atmosphere, and the exhaust gas (14) of the gas engine (10) is processed into the carbon dioxide-rich gas mixture (44). The gas atmosphere in the combustion chamber has an oxygen content (33) that corresponds to 0.9 to 1.1 times the amount of oxygen required for complete combustion of the hydrocarbon-containing fuel (21), and the gas atmosphere has a volumetric ratio of nitrogen to oxygen (33) in that is less than 3.5 to 1. The invention also relates to an apparatus for producing the carbon dioxide-rich gas mixture (44), and a method and apparatus for enhanced oil recovery using the method and apparatus for producing the carbon dioxide-rich gas mixture (44).

Abstract: A method of operation of an electric turbocompounding system for a reciprocating engine comprises the steps of retrieving from the engine ECU data pertaining to engine condition, retrieving from a set of turbine efficiency data an optimum turbogenerator speed at the engine condition, setting a desired turbogenerator set speed based on the engine condition and on a speed at which turbine efficiency is deemed to be optimum, measuring an output voltage of the turbogenerator, comparing the measured voltage with a pre-determined voltage range and where the measured voltage falls outside of the pre-determined voltage range, adjusting the turbogenerator set speed to reduce or increase the output voltage to within the pre-determined voltage range.

Abstract: An engine having one of a plurality of exhaust valves in each cylinder that may be deactivated is disclosed. In one example, one exhaust valve of each cylinder is deactivated in response to engine speed. The engine may have improved engine torque at low engine speeds and reduced time to torque (e.g., turbo lag).

Abstract: Methods and systems are provided for an engine including a first turbocharger having a first compressor and a second turbocharger having a second compressor. An EGR differential between the first compressor and the second compressor may be increased under a condensation condition, and decreased under a surge condition. The EGR differential may also be decreased when a compressor outlet temperature exceeds an outlet temperature threshold.

Abstract: A method for providing intake air to an engine in a vehicle includes forming a mixture of fresh air and treated exhaust, and compressing the mixture upstream of a first throttle valve coupled to an intake manifold of the engine. The method further includes, during a higher engine-load condition, admitting the mixture to the intake manifold via the first throttle valve, and, during a lower engine-load condition, admitting fresh air to the intake manifold via a second throttle valve.

Abstract: A turbocharger including a turbine wheel having a hub-to-tip ratio of no more than 60% and blades with a high turning angle, a turbine housing forming an inwardly spiraling primary-scroll passageway that significantly converges to produce highly accelerated airflow into the turbine at high circumferential angles, and a two-sided parallel compressor. The compressor and turbine each produce substantially no axial force, allowing the use of minimal axial thrust bearings.

Abstract: An internal combustion engine includes an exhaust restriction valve and an exhaust gas recirculation control valve. Upon determining that a malfunction or fault condition exists relative to one of the valves, the controller may command the other valve to move towards a predetermined position. A malfunction or fault condition may result in derating of the engine.

Abstract: Methods and systems are provided for operating an engine including an SCR catalyst downstream of an exhaust turbine and a particulate filter upstream of the turbine. In one example, the method comprises, adjusting a turbine wastegate to adjust a catalyst temperature to a desired catalyst temperature.

Abstract: Methods and systems are provided for operating an engine including an emission control system, the emission control system comprising a catalyst downstream of a turbine of a boosting device and a reductant injector upstream of the turbine. In one example, the method comprises injecting reductant into exhaust upstream of the turbine, mixing the injected reductant with exhaust gas via the turbine, and delivering the mixed reductant to the catalyst.

Abstract: In a method for operating an actuator for a wastegate actuating device of an exhaust gas turbocharger, a wastegate situated in an exhaust branch of an internal combustion engine is electrically adjustable with the aid of the actuator, and an exhaust gas quantity flowing through the exhaust gas turbocharger is adjustable as a function of an opening position of the wastegate. The actuator is controlled using an applied electrical power in a closed position of the wastegate to provide a varying closing pressure of the wastegate as a function of a characteristic curve of an exhaust gas counterpressure applied via the wastegate.

Abstract: An exhaust gas recirculation valve is configured as a butterfly valve and includes a body with a generally uniform diameter bore therethrough. A generally circular plate is mounted within the bore and is rotatable between a first open position and a second closed position. The generally circular plate is dimensioned to provide a enlarged gap between an outer edge of the generally circular plate and the bore when at the second closed position.

Abstract: A turbocharger for an internal combustion engine includes a center housing, a shaft rotatably supported in the center housing, and a turbine wheel connected at one end of the shaft. A turbine housing is connected to the center housing and disposed around the turbine wheel. A bore formed in the turbine housing extends from a gas outlet end of the turbine housing to an annular stop surface of the turbine housing disposed adjacent the turbine wheel. A nozzle ring disposed in the bore surrounds a portion of the turbine wheel. An outlet cone is disposed at least partially in the bore and surrounds a remaining portion of the turbine wheel. The outlet cone is connected to the gas outlet end of the turbine housing.

Abstract: A determination is made more simply as to a malfunction of a low pressure EGR device that supplies an EGR gas from a low pressure EGR passage connecting between an exhaust passage at a location downstream of a turbine and an intake passage.

Abstract: An EGR device includes a first cooling passage that introduces a flowing medium discharged from an engine into a main radiator so that the flowing medium is cooled therein, and then returns the flowing medium to the engine, and a second cooling passage that introduces a part of the flowing medium cooled in the first cooling passage to a sub-radiator so that the flowing medium is further cooled therein. The second cooling passage introduces the flowing medium to an EGR cooler to return the flowing medium, which is discharged from the EGR cooler, to the engine.

Abstract: A butterfly valve includes a body with a bore through which exhaust gas may flow and a valve member rotatably mounted within the bore for restricting flow through the bore. A stop extends into the bore to limit movement of the valve member and prevent the valve member from rotating to a closed position. The stop defines a restricted flow position at which the valve member is positioned between an open position and the closed position. An internal combustion engine utilizing the butterfly valve is also provided.

Abstract: A method and system to control an engine to maintain turbine inlet temperature utilizes two temperature thresholds: a control initiation temperature and a maximum hardware temperature. An engine parameter is adjusted in a closed-loop manner based on an error, which is a difference between a setpoint temperature and the turbine inlet temperature. The setpoint temperature is initially the control initiation temperature. However, after control over turbine inlet temperature is established, the setpoint temperature ramps gradually to maximum hardware temperature. In one embodiment, the engine parameter is engine torque. Other engine parameters affecting turbine inlet temperature include timing and duration of fuel injection pulses, EGR rate, gear selection, and intake throttle position, any of which can be used in place of, or in combination with, torque for controlling turbine inlet temperature.

Abstract: In one aspect, the present disclosure is directed to a system for reacting with sulfuric acid. The system may include a housing having an inlet and an outlet and may also include a component disposed downstream of the inlet and upstream of the outlet. The component may be configured to restrict a flow of fluid through the housing as a function of sulfuric acid present within the fluid.

Abstract: A method of heating an engine exhaust gas of an engine, including flowing a first exhaust gas at a first temperature within and along internal flow channels of a catalyst brick, and flowing a second exhaust gas at a second, different, temperature around an exterior of the catalyst brick. Heat may be transferred between the gases and the catalyst brick to achieve various operations.

Abstract: In a multi-stage charging group for receiving an operating fluid of an internal combustion engine which includes a first and a second turbocharger with a first and, respectively, a second turbine arranged in a common support housing, a bypass guide structure is provided in the support housing for guiding the operating fluid around the first turbine, which guide structure is formed at least partially by the support housing and a housing section of the first turbine.

Abstract: An internal combustion engine exhaust gas system includes a filter arranged in an exhaust passage of the internal combustion engine, a fuel adding valve which is arranged upstream of the filter and supplies fuel into the exhaust passage, and a low-pressure exhaust gas recirculation apparatus that removes some of the exhaust gas from downstream of the filter as EGR gas. An EGR rate is controlled taking into account the amount of fuel supplied by the fuel adding valve such that an oxygen concentration of intake gas, which is drawn into a cylinder of the internal combustion engine in a state in which the EGR gas that is introduced by the low-pressure exhaust gas recirculation apparatus is mixed with air introduced into an intake passage, is constant before and after fuel is supplied by the fuel adding valve.

Abstract: An exhaust gas recirculation device for an internal combustion engine having a supercharger has an intake air passage that intakes intake air for the internal combustion engine, an exhaust passage that carries away exhaust air from the internal combustion engine, an exhaust gas recirculation passage connected to the intake air passage, and an exhaust gas recirculation valve interposed within the exhaust gas recirculation passage. The exhaust gas recirculation passage recirculates a part of the exhaust gas based on an openness of the exhaust gas recirculation valve to control an amount of exhaust recirculation introduced into the intake air passage. A first end of the exhaust gas recirculation passage is connected to the intake air passage upstream of a compressor of the supercharger. A second end of the exhaust gas recirculation passage is connected to the exhaust passage downstream of a turbine of the supercharger.

Abstract: A control apparatus for an internal combustion engine includes a turbocharger; an exhaust gas purifying catalyst which is arranged at a section downstream of a turbine in the exhaust passage; and a low pressure EGR passage which connects a section downstream of the exhaust gas purifying device in the exhaust passage and a section upstream of a compressor in the intake passage. The compressor is provided with a movable vane mechanism capable of varying throttled quantity of a flow passage of intake gas by moving diffuser vanes. The movable vane mechanism is controlled so that the throttled quantity of the flow passage is decreased when the exhaust gas is led to the compressor via the low pressure EGR passage as compared with a case when the exhaust gas is not led to the compressor.

Abstract: The present invention relates to a turbocharger (1) for an internal combustion engine (2), having at least one low-pressure exhaust-gas recirculation line (3) which opens out via an exhaust-gas mixing-in opening (12) into an intake line (10) of the internal combustion engine (2); having a turbine (4) and having a compressor (5) which is drive-connected to the turbine (4) and which has a compressor wheel (6) which is arranged in a compressor housing (7) into which the intake line (10) opens out via a compressor inlet (11), and having a mixing device (18) for mixing recirculated exhaust gas (AG) and fresh air (FL), characterized in that the mixing device (18) has an inflow distributor (21) in which the exhaust-gas recirculation line (3), which extends at least substantially along the longitudinal axis (L) thereof, and the intake line (10), which extends at least substantially at right angles to the longitudinal axis (L), open out, and in that, as viewed in the flow direction (R) of the exhaust gases (AG), an im

Abstract: By providing an electrically-controlled turbocharger (ECT) on a compression-ignition (CI) engine, the engine can be provided a desired lambda and a desired EGR fraction over the range of operating conditions. When lambda in the exhaust is leaner than the desired lambda, electrical energy to the electric motor of the ECT is reduced to bring actual lambda to desired lambda. Analogously, when lambda in the exhaust is richer than the desired lambda, electrical energy to the ECT is increased.

Abstract: A gear subassembly is for an exhaust gas recirculation (EGR) system including an EGR valve and a rotatable shaft provided for the EGR valve. The gear subassembly includes a gear and a cam. The gear is a part of reduction gears and is fastened to the rotatable shaft to rotate therearound. The cam is fastened to the gear and is a part of a link mechanism. The gear includes a metal shaft-fastening part used for fastening the gear to the rotatable shaft, and a metal cam-fastening part used for fastening the gear to the cam. The gear is formed by resin-molding with the shaft-fastening part and the cam-fastening part serving as insert parts.

Abstract: A circuit for feeding at least one fluid to an internal-combustion engine, notably of Diesel type, includes a circuit (20) for supercharging air to the engine intake, including a supercharging pipe (36), a supercharging device (28) with a compression stage (26) and a compressed air cooling radiator (38), as well as a circuit (22) for recirculating the exhaust gas to the engine intake, including an exhaust gas recirculation pipe (40) and an exhaust gas cooler (46). The feed circuit includes a connecting pipe (50) allowing to connect, upstream from cooler (46), air supercharging circuit (20) and exhaust gas recirculation circuit (22).

Abstract: An apparatus, system, and method are disclosed for efficiently operating an engine utilizing exhaust gas recirculation (EGR). The apparatus includes an exhaust manifold receiving exhaust gas from a first cylinder set, an EGR manifold receiving exhaust gas from a second cylinder set, and a passage comprising a variable restriction. The passage fluidly couples the exhaust manifold to the EGR manifold. The apparatus further includes a controller with modules for interpreting engine operating conditions and controlling actuators in response to the engine operating conditions.

Abstract: In an internal combustion engine comprising an exhaust gas turbocharger, which includes a compressor with a compressor wheel arranged in an inlet tract of the internal combustion engine and a turbine with a turbine wheel coupled rotationally to the compressor wheel and arranged in an at least two-path exhaust gas tract of which is connected to an exhaust gas guide section of the turbine including at least a first spiral channel coupled to the first exhaust path and a second spiral channel coupled to a second exhaust gas path, two guide vane elements are arranged upstream of the turbine wheel and downstream of respective spiral channels which are formed corresponding to a first degree of asymmetry A1 determined as a quotient ? of a first mass flow parameter and a second mass flow parameter which is between 0.4 and 0.8.

Abstract: A closely-coupled exhaust aftertreatment system includes a first exhaust conduit comprising a first valve operable between a first position promoting an exhaust flow within the first exhaust conduit to an inlet of a first oxidation catalyst and a second position promoting the exhaust gas flow within a second exhaust conduit. It also includes a third exhaust conduit fluidly coupled to an outlet of the OC and comprising a second valve operable between a first position promoting an exhaust flow within the third exhaust conduit to an inlet of a particulate filter (PF) and a second position promoting the exhaust gas flow through a fourth exhaust conduit to an inlet in the second exhaust conduit. It further includes a turbocharger fluidly coupled to the second exhaust conduit downstream of the inlet and a selective catalyst reduction (SCR) catalyst that is located downstream of the turbocharger and upstream of the PF.

Abstract: An exhaust gas assembly includes an exhaust gas manifold which is connected with an exhaust gas inlet of a manifold and an adjusting member arranged in the manifold. The adjusting member is configured to supply exhaust gas to a low pressure connection and/or a high-pressure connection of the manifold, wherein on the high-pressure side a high-pressure turbine housing is connected to the manifold and on the low pressure side a low pressure turbine housing is connected to the manifold. A connecting channel extends through the manifold and connects a high-pressure exhaust gas outlet) of the high-pressure turbine housing with a low pressure exhaust inlet) of the low pressure turbine housing.

Abstract: An engine system may include an electric or mechanical supercharger and an LP-EGR, basically with a turbocharger, an EGR valve, a channel control valve, and a bypass valve, which control the flow rate of external air and exhaust gas, may be integrally operated, and a operation section may be divided into a turbo-lag and low torque section, a mid-load section, and mid/high-load section such that the open amount of EGR valve, channel control valve, and bypass valve may be optimally controlled, such that it may be possible to improve availability for a low-speed/high-load section with turbo-lag reduced, using supercharger and considerably increase the ratio of fuel efficiency improvement in the low-speed/high-load section, using LP-EGR operating with supercharger.

Abstract: A system for driving an EGR stream for an engine includes an exhaust gas turbine, a main compressor and a supplemental EGR compressor. The turbine drives the main compressor to pressurize intake air and drives the supplemental EGR compressor to pressurize an EGR exhaust gas stream to be introduced into the intake air system. A supplemental EGR compressor takes suction of exhaust gas downstream from the turbine. A three-way valve proportions exhaust gas between the engine exhaust gas discharge conduit and the suction of the supplemental EGR compressor. The turbine drives a shaft and the main compressor and the supplemental EGR compressor are driven by having corresponding compressor wheels fixed onto the common shaft.

Abstract: An internal combustion engine arrangement includes an EGR circuit connecting a exhaust circuit to an intake circuit to incorporate a portion of exhaust gases in the intake gases, at least one turbine located, and a dedicated drain conduit which connects the EGR circuit to the exhaust circuit. The EGR circuit includes at least one low position point and the dedicated drain conduit permanently connects the low position point of the EGR circuit to the exhaust circuit upstream of the turbine.

Abstract: One illustrative embodiment includes a turbocharger (16, 18) with a turbine (94) and a compressor (96). The turbine (94) has an inlet passage (114) which may directly communicate with a blowdown exhaust port (34, 36, 38) of a cylinder head (12) of an internal combustion engine (14). The inlet passage (114) may directly receive exhaust gas from the blowdown exhaust port (34, 36, 38).

Abstract: An internal combustion engine includes a plurality of cylinders, an air intake line and an exhaust line collecting exhaust gas. The engine also includes an EGR line for rerouting a part of the exhaust gas from the exhaust line towards the air intake line and at least a first turbocharger comprising a first turbine driven by the exhaust gas flowing towards the atmosphere, linked to a first compressor located on the air intake line. The engine further includes a variable geometry EGR turbine located on the EGR line, driven by the EGR gas flowing in the EGR line. Thus, thanks to the pressure reduction occurring in the turbine, the EGR gas temperature is lowered, and less cooling power from the engine cooling system is required to cool down the EGR.

Abstract: When a failure occurs in synchronizing mechanism, an intake air throttle valve is rotated in a direction that is opposite from a normal operational time valve closing direction, so that an arm of a driven plate contacts a throttle valve side stopper to stop rotation of the intake air throttle valve. Thereafter, when a low pressure EGR valve is rotated from a full close position to a full open position, an EGR valve side stopper contacts the arm of the driven plate to stop the low pressure EGR valve. A rotational angle of the EGR valve is sensed with a sensor and is outputted to an ECU. The ECU determines that a failure mode is set when a valve angle sensed with the sensor coincides with a rotation stop position of the EGR valve.

Abstract: An exhaust system for a use with an engine is provided. The exhaust system may have an exhaust manifold configured to direct exhaust from the engine, and a main turbocharger connected to receive exhaust from the exhaust manifold. The exhaust system may also have a recirculation turbocharger having a compressor connected to receive exhaust from the exhaust manifold in parallel with the main turbocharger, and a turbine connected to receive exhaust from the main turbocharger to drive the compressor. The exhaust system may further have a control valve located downstream of the recirculation turbocharger to regulate exhaust flow through the compressor.

Abstract: An exhaust system for a use with a combustion engine is provided. The exhaust system may have a first exhaust manifold configured to receive exhaust from the engine, and a first turbocharger driven by exhaust from the first exhaust manifold. The exhaust system may also have a second exhaust manifold configured to receive exhaust from the engine in parallel with the first exhaust manifold, and a second turbocharger driven by exhaust from the second exhaust manifold and having a different flow capacity than the first turbocharger. The exhaust system may further have an exhaust gas recirculation circuit in fluid communication with the second exhaust manifold.

Abstract: The present invention relates to an internal combustion engine (1), having an intake section (2) which has an intake line (3) in which a compressor (4) of an exhaust-gas turbocharger (5) is arranged; having an exhaust section (6) which has an exhaust line (7) in which a turbine (8) of the exhaust-gas turbocharger (5) is arranged; and having a low-pressure exhaust-gas recirculation device (9) which has an exhaust-gas recirculation line (10) which branches off from the exhaust line (7) downstream of the turbine (8) and which opens into the intake line (3) upstream of the compressor (4) and in which an exhaust-gas recirculation valve (11) is arranged. Here, a throttle device (12) is arranged in the intake line (3) upstream of the compressor (4).

Abstract: An internal combustion engine includes a plurality of combustion cylinders, at least one turbocharger, an exhaust gas line and an exhaust gas recirculation system. A compressor bypass may fluidly connect a compressed air line to the exhaust gas line. If the internal combustion engine has dual cylinder banks, an exhaust gas balance tube may extend between exhaust gas lines of the cylinder banks. A wastegate may fluidly connect the exhaust gas balance tube to an exhaust gas outlet. A compressor bypass may fluidly connect the compressed air line to the exhaust gas balance tube.

Abstract: An internal combustion engine includes a plurality of combustion cylinders, at least one turbocharger, an air supply line, an exhaust gas line and an exhaust gas recirculation system. An exhaust manifold of the exhaust gas line may have both non-direction specific and modular pulse exhaust manifold elements. If the internal combustion engine has dual cylinder banks, an exhaust gas balance tube may extend between exhaust gas lines of the cylinder banks and be fluidly connected to an exhaust manifold between the ends thereof.

Abstract: The invention relates to a V engine (1), especially a diesel engine, comprising a first cylinder bank (2) and a second cylinder bank (3), said V engine being designed for two-stage charging by means of a low-pressure exhaust gas turbocharger (4, 5) and a high-pressure exhaust gas turbocharger (6, 7). The invention is characterised in that the low-pressure exhaust gas turbocharger (4, 5) and the high-pressure exhaust gas turbocharger (6, 7) are respectively arranged on the front of a cylinder bank (2, 3) above a main output element (23) of the V engine (1).

Abstract: An internal combustion engine includes a plurality of cylinders, an air intake line and an exhaust line collecting exhaust gas. The engine also includes an EGR line for rerouting a part of the exhaust gas from the exhaust line towards the air intake line and at least a first turbocharger comprising a first turbine driven by the exhaust gas flowing towards the atmosphere, linked to a first compressor located on the air intake line. The engine further includes a variable geometry EGR turbine located on the EGR line, driven by the EGR gas flowing in the EGR line. Thus, thanks to the pressure reduction occurring in the turbine, the EGR gas temperature is lowered, and less cooling power from the engine cooling system is required to cool down the EGR.

Abstract: Systems and methods for supplying air to an engine are disclosed. In one example, an air inlet throttle is at least partially closed in response to a change in engine torque request. In another example, the air inlet throttle is adjusted in conjunction with adjusting an engine throttle. The approach can reduce compressor noise and may reduce the possibility of compressor surge.

Abstract: A closely-coupled exhaust aftertreatment system for an engine having twin turbochargers includes a first exhaust conduit comprising a first valve operable between first and second positions, the first promoting flow within the first conduit to an oxidation catalyst (OC), the second promoting flow within a second conduit; a third conduit is fluidly coupled to the OC outlet and includes a second valve operable between first and second positions, the first promoting flow within the third exhaust conduit to a particulate filter (PF), the second promoting flow through a fourth conduit to an inlet in the second conduit. A first turbocharger is coupled to the second exhaust conduit downstream of the inlet; an SCR catalyst is downstream of the first turbocharger to receive the flow therefrom and upstream of the PF to provide the flow thereto. A second turbocharger is coupled to the third exhaust conduit downstream of the second valve.