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: A turbocharger system comprises a first relatively small turbocharger and a second relatively large turbocharger connected in series and an exhaust gas flow control valve. The exhaust control valve has an inlet port communicating with the exhaust gas flow upstream of the first turbine a first outlet port communicating with the exhaust flow downstream of said first turbine but upstream of said second turbine, and a second outlet port communicating with the exhaust flow downstream of said second turbine. The valve is operable to selectively permit or block flow through the first and second outlet ports.

Abstract: Arrangement of a two stage turbocharger system for an internal combustion engine including an intake manifold and an exhaust manifold, including a low-pressure turbocharger, a high-pressure turbocharger and a bypass duct in flow communication with an outlet of the low-pressure compressor, an inlet of the high-pressure compressor, an outlet of the high-pressure compressor and an inlet of the intake manifold. The bypass duct includes a first bypass valve for opening and closing the bypass duct. The first bypass valve and the high-pressure compressor are accommodated within a common housing.

Abstract: A combustion engine includes a first turbocharger that compresses charge air in a first compressor stage and a second turbocharger that further compresses the air compressed in the first turbocharger and that feeds the further compressed air to the combustion engine. A charge air cooler is disposed between the first and the second turbocharger and is configured to cool the air compressed by the first turbocharger.

Abstract: The present application and the resultant patent provide a waste heat recovery system for recovering heat from a number of turbocharger stages. The waste heat recovery system may include a simple organic rankine cycle system and a number of charge air coolers in communication with the turbocharger stages and the simple organic rankine cycle system. The charge air coolers are positioned in a number of parallel branches of the simple organic rankine cycle system.

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: A system for a sequential turbocharger includes a mode selection module, a feed-forward selection module, and a control loop module. The mode selection module generates a control mode signal based on an engine speed signal, an engine torque signal, and an engine mode signal. The control mode signal indicates one of an open-loop control mode and a closed-loop control mode. The feed-forward selection module determines a feed-forward value based on the control mode signal, the engine speed signal, and the engine torque signal. The control loop module determines a loop control value at least one of based on the feed-forward value, a variable geometry turbine (VGT) control signal, and an error signal; and based on a bypass valve (BPV) control signal and the error signal when the control mode signal transitions from the open-loop control mode to the closed-loop control mode.

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: 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: 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: Disclosed is a pipe arrangement (1) comprising a pipe element (2) that is used to connect, in particular fluidically connect, a turbine outlet of one turbocharger (15) to a turbine inlet of another turbocharger (17). The pipe arrangement is characterized in that a first pipe section (8) of the pipe element (2) includes a first fastening device (14) for attaching a first turbocharger (15) as well as a second fastening device (20) for attaching the pipe element (2) to a first support element (21) of an internal combustion engine. Furthermore, a second pipe section (9) includes a third fastening device (16) for attaching a second turbocharger (17) as well as a fourth fastening device (24) for attaching the pipe element (2) to a second support element (25) of an internal combustion engine.

Abstract: A turbomachine system comprises a first turbocharger comprising an exhaust gas flow first turbine for location in an exhaust path and a first compressor driven by said first turbine; a turbomachine for location in the exhaust path upstream or downstream of said first turbocharger and comprising an exhaust gas flow second turbine and a second compressor driven by said second turbine. The first turbine has an outlet that is in fluid communication with an inlet of the second turbine. One of said first and second turbines is a radial outflow turbine. The arrangement provides for a relatively compact package. The radial outflow turbine may have a particular structure in which there is provided a deflector member at or near its inlet for directing the gas outwards, a stator for introducing swirl and a downstream turbine rotor. A shroud is fixed to blades of the turbine rotor to prevent leakage and to provide additional structural rigidity.

Abstract: A method of controlling a turbocharger for an engine and a control system for the same includes a variable nozzle turbine control module operating a variable nozzle turbine of a high pressure turbocharger closed loop in a first load-engine speed region. The system also includes a high pressure turbine bypass valve control module operating a high pressure turbine bypass valve in a closed position in a first load-engine speed region. The variable nozzle turbine control module operates a variable nozzle turbine closed loop in a second load-engine speed region between the first load-speed region and a third load speed region. The high pressure turbine bypass valve module operates the high pressure turbine bypass valve in a transient region in the second load-engine speed region. The variable nozzle turbine control module operates the variable nozzle turbine open loop.

Abstract: Embodiments for controlling exhaust flow are provided. Example embodiments include a cylinder head having two integrated exhaust manifolds, wherein each exhaust manifold is coupled to a turbine of a turbocharger. After passing over the turbines, the exhaust gas may exit through a shared balcony-like projection arranged between the exhaust manifolds.

Abstract: Embodiments for a turbocharged engine including two turbochargers are provided. In one example, a turbocharger engine includes two turbochargers arranged in parallel, each coupled to a separate exhaust manifold. Bypass of exhaust around both turbochargers may be provided via a single wastegate.

Abstract: A turbine system for a multistage turbocharger and a method for utilizing the same are disclosed. The turbine system includes a high pressure turbine having an inlet for receiving a flow of fluid, and an outlet for passing the flow on extraction of work from the high pressure turbine. The system further includes a low pressure turbine, having an inlet for receiving a flow of fluid from the high pressure turbine. A diffuser connects the outlet of the high pressure turbine and the inlet of the low pressure turbine. The system also includes a bypass channel for bypassing a portion of the flow around the high pressure turbine, from upstream of the high pressure turbine to downstream of the high pressure turbine. The system includes an injector to input the bypass flow in the diffuser in a manner to reduce flow separation in the diffuser.

Abstract: An internal combustion engine including a two-stage turbocharger configuration is described. Located between the turbines of the two-stage turbocharger may be an oxidation catalyst and a passive NOx adsorber or an oxidation catalyst and an SCR device. An exhaust path extending from an engine body of the internal combustion engine to the second turbine of the two-stage turbocharger configuration may also include one or more hydrocarbon sources or one or more ammonia sources. A bypass valve arrangement may permit decreased flow through the first stage of the two-stage turbocharger arrangement as well as one or more of the elements positioned between the turbines of the two-stage turbocharger.

Abstract: A kit for producing automobiles having different engine variants of auto-ignition internal combustion engines, each engine having two cylinder banks arranged in a V-shape, and components of a turbocharging and/or exhaust gas system is described. All internal combustion engines have mounting elements enabling installation of the components of the turbocharging and/or exhaust gas system in an identical relative position with respect to the internal combustion. Identical or modularized parts can then be used for the turbocharging and/or exhaust gas systems for all engine variants which can be mounted in the same sequential order. Automobiles having different engine variants can thus be manufactured with particularly low inventory and assembly costs.

Abstract: An engine system is disclosed. The engine system includes an engine, an intake system for providing intake air to the engine and an exhaust system receiving exhaust gas from the engine. The engine system also includes a first exhaust turbine arranged downstream of the engine and a second and third exhaust turbines coupled in parallel and arranged downstream of the first exhaust turbine. A first valve is associated with the second and third exhaust turbines, the first valve configured to at least partially restrict exhaust gas to one of the second and third exhaust turbines and increase exhaust gas to the other turbine. The engine system also includes an exhaust gas recirculation system configured to redirect at least a portion of exhaust gas from the exhaust system to the intake system.

Abstract: One embodiment of the invention includes a combustion engine breathing system including a compressor valve for use with a biturbo system and cylinder deactivation.

Abstract: The present invention relates to a turbo-charged reciprocating piston engine having a combustion chamber, and to a method for operating said engine. The combustion chamber has at least one inlet valve (10), one outlet valve (13) and at least one additional charging valve (11), for the additional feed of compressed air to bridge the turbo lag. All the valves (10, 11, 13) are operatively connected to the crankshaft via a camshaft and the operative connection of the charging valves to the crankshaft can be deactivated, with the result that the at least one charging valve (11) remains closed. The correct metering of the air for a stoichiometric or approximately stoichiometric combustion mixture is additionally achieved by a turbocharger (4) and a throttle valve (8). By displacement of the opening instant of the charging valves (11), air can be pumped from the cylindrical combustion chambers into the compressed air tank (14), instead of removing said air from the latter.

Abstract: Thermal management systems and methods related to controlling temperature of internal combustion engines are provided. In one embodiment, a thermal management system includes an air intake structure defining an air intake passage therethrough coupled to a plurality of cylinders in an engine, a first turbocharger including a first compressor positioned in the air intake passage, a second turbocharger including a second compressor positioned in the air intake passage between the first compressor and the plurality of cylinders, a multi-stage cooling assembly, positioned in the air intake passage between the first compressor and the second compressor, including an air-to-coolant intercooler for cooling intake air and an air-to-air heat exchanger for cooling intake air, and an air-to-coolant radiator fluidly coupled with the air-to-coolant intercooler of the multi-stage cooling assembly.

Abstract: Method of operating an internal combustion engine, including, at least, compressing and cooling air outside an engine chamber, supplying cooled, pressurized air to an intake port associated with the chamber, and, during each engine cycle: opening the intake port, allowing cooled, pressurized air to flow through the intake port and into the chamber during at least a portion of the intake stroke; maintaining open the intake port during the portion of the intake stroke and beyond the end of the intake stroke and into the compression stroke and during a majority portion of the compression stroke; closing the intake port at a point during travel of the piston to capture in the chamber a cooled compressed charge of the cooled, pressurized air; controllably delivering fuel into the chamber after the cooled compressed charge is captured within the chamber; and igniting a fuel and air mixture within the chamber.

Abstract: In an internal combustion engine having two exhaust gas turbochargers which are connected in series and a bypass line which bypasses the exhaust gas turbine close to the engine and extends to a collecting space of the turbine remote from the engine, and a blow-off valve is integrated into the turbine housing of the remote exhaust gas turbine for controlling a communication path between the collecting space and the turbine wheel, and includes a control sleeve supported axially movably between a closed position in which the communication path is blocked and a fully open position in which a flow path by-passing the turbine wheel of the turbine remote from the engine is provided.

Abstract: Exemplary embodiments of the present invention are directed towards a turbocharger for an internal combustion engine and more particularly an apparatus and method for fluidly coupling a turbocharger with an internal combustion engine. In one embodiment a turbocharger housing is provided. Turbocharger housing includes a turbine housing defining a volute chamber. The turbocharger housing also includes a first housing support extending from the turbine housing. The first housing support is integrally formed with the turbine housing and the first housing support defines an inlet opening and an outlet opening each of which are in fluid communication with the volute chamber.

Abstract: An internal combustion engine control apparatus that prevents an abrupt change in the air amount at the time of supercharger switching. The control apparatus enters a small turbo operating state in which a small turbocharger is mainly operative, during relatively low-rotation-speed and low-load side, and enters a large turbo operating state in which a large turbocharger is mainly operative, in a relatively high-rotation-speed and high-load. In the small turbo operating state, the control apparatus can exercise charging efficiency enhancement control by using a scavenging effect. Before switching from the small turbo operating state to the large turbo operating state, the control apparatus predicts whether the large turbocharger will build up its boost pressure quickly or slowly. When slow boost pressure is predicted, the control apparatus exercises charging efficiency enhancement control to provide a low degree of charging efficiency enhancement.

Abstract: In a method for controlling the operation of an internal combustion engine, a target torque to be produced is determined in several steps: In a first step a torque requested by a user is determined and modified in subsequent steps by different functions, which reproduce the influences of at least one continuously determined working and/or operating parameter of the engine on the torque that is actually produced, in such a way that at the end of the steps the target torque required during the engine operation is defined and the engine operation and the determination of the working and/or operating parameter are monitored for errors. If errors occur, diagnostic values that describe or indicate the errors are generated and used to modify, in particular limit the target torque. The diagnostic values are individually assigned to the individual steps to modify the determination or modification of the torque performed in each step.

Abstract: Systems and methods for reducing NOx emissions using a branched exhaust system with a first and second turbine including an emission-control device containing a zeolite, are described. In one example approach, a method comprises: during a first duration when exhaust temperature is below a first temperature threshold, directing exhaust gas through the second turbine and the emission-control device, and adjusting the second turbine to control intake boost; and during a second duration following the first, directing exhaust gas through the first turbine, and adjusting the first turbine to control intake boost. In this way, the first and second turbines may provide a greater degree of boost control in order to reduce boost fluctuations while enabling storing cold start NOx emissions for later reduction.

Abstract: The intake air cooler of the invention comprises a first cooling stage (24) and a second cooling stage (26) grouped in a single heat exchanger housing (30) and sharing a common heat exchanger bundle (28) accommodated in the housing and traversed by a cooling liquid. Application to turbocharged internal combustion engines for motor vehicles.

Abstract: A single-shaft exhaust gas-driven turbocharger includes two parallel-flow first-stage centrifugal compressors in series with a single second-stage centrifugal compressor, and a one-stage turbine arranged to drive both the first- and second-stage centrifugal compressors via a single shaft on which the compressors and turbine are fixedly mounted. The compressor housing defines from one to a plurality of circumferentially spaced inlet ducts for the second wheel of the first stage, and from one to a plurality of circumferentially spaced interstage ducts leading from a vaneless diffuser of the first stage into the inlet of the second stage.

Abstract: One embodiment is a unique system which is operable to provide a mixture of charge air and exhaust to an internal combustion intake at a sub-ambient temperature. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Abstract: An exhaust system for a use with a combustion engine is provided. The exhaust system may have a first exhaust manifold, a second exhaust manifold, and an exhaust gas recirculation circuit. The exhaust system may also have a fixed geometry turbocharger with a first volute configured to receive exhaust from the first exhaust manifold, and a second volute configured to receive exhaust from the second exhaust manifold. The exhaust system may also have a recirculation control valve in fluid communication with the first exhaust manifold, the second exhaust manifold and the exhaust gas recirculation circuit. The recirculation control valve may have a valve element movable to selectively adjust a flow of exhaust in the exhaust gas recirculation circuit, the first volute, and the second volute.

Abstract: An internal combustion engine has at least one cylinder group including a plurality of cylinders and at least one exhaust turbocharger, each cylinder including a plurality of outlet valves for exhaust gas, each outlet valve being assigned an outlet duct which opens into an exhaust manifold and via which the respective exhaust gas, after flowing through the respective outlet valve and outlet duct, can be guided in the direction of an exhaust turbocharger, and first outlet ducts of the cylinders being contoured in the manner of nozzles, and second outlet ducts of the cylinders being contoured in the manner of diffusers.

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, a second exhaust manifold configured to receive exhaust from the engine in parallel with the first exhaust manifold, and an exhaust gas recirculation circuit in fluid communication with only the first exhaust manifold. The exhaust system may also have a first turbocharger having dual volutes configured to simultaneously receive exhaust from the first exhaust manifold and the second exhaust manifold, and a second turbocharger configured to receive exhaust from the first turbocharger and compress air directed into the engine.

Abstract: A dual-inlet turbocharger system for internal combustion engine includes a single-shaft turbocharger with a dual-inlet compressor section. An air router provides a bifurcated air supply for the dual-inlet compressor section, and also provides a bifurcated source of charge air for the engine's cylinders in the case in which the present turbocharger system is applied to a V-block engine.

Abstract: In a gas fueled internal combustion engine, in particular a natural gas fueled internal combustion engine, as well as in a method for fuelling an internal combustion engine with gas, in particular with natural gas, with a charged “downsizing” Otto engine and an injection of the gas, a homogenous stoichiometric gas-air mixture is set and the charging takes place by an exhaust turbo charger as well as a compressor, which can be turned off and is located above the exhaust turbo charger in the air suction route.

Abstract: An air-to-fluid intercooler is disclosed. The air-to-fluid intercooler may include a core assembly including an outer circumference and an inner circumference, at least one annular tube body configured to direct flow of a cooling fluid within the core assembly, and at least one curved fin coupled to an exterior surface of the at least one annular tube body and configured to direct a flow of charge air through the core assembly.

Abstract: A supercharger compressor includes a plurality of rotors rotatably mounted in a housing, a first inlet for air, a second inlet for recirculated exhaust gas, and a flow separator. The flow separator is arranged interior the housing and configured to form a slideable seal with at least one rotor of the plurality of rotors, the slideable seal fluidically isolating the first inlet from the second inlet, at least in part, and retarding pressure equalization therebetween.

Abstract: The invention is based on an arrangement of supercharging units (1, 5, 6, 7), which arrangement is to be attached in the construction space of a motor vehicle, for supercharging an internal combustion engine with a fluid (23) comprising charge air and/or exhaust gas, wherein the supercharging units (1, 5, 6, 7) comprise at least one heat exchanger (5, 6, 7) and at least one compressor (1). According to the concept of the invention, the supercharging units (1, 5, 6, 7) are arranged combined in a module (10A, 10B) and, in order for the same to be kept together in the module (10A, 10B), the supercharging units (1, 5, 6, 7) are connected at any rate partially to one another in a fluid-conducting manner, and at least one of the supercharging units (1, 5, 6, 7) is held on a holding structure. This enables the supercharging units to be handled flexibly, simply and nevertheless in a manner saving on construction space and outlay on connection. The invention also leads to a production method.

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 at least one 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 at least two turbochargers driven by exhaust from the second exhaust manifold. The exhaust manifold may further have an exhaust gas recirculation circuit in fluid communication with only the first exhaust manifold. A number of turbochargers that receives exhaust from the first exhaust manifold may be less than a number of turbochargers that receives exhaust from the second exhaust manifold.

Abstract: A system for recovering engine exhaust energy is provided. The system includes an exhaust system including a first exhaust branch and a second exhaust branch. The system includes a first and a second group of exhaust valves associated with a plurality of engine cylinders. The system also includes an energy recovering assembly. The system further includes a control mechanism configured to control at least one of the first and second groups of exhaust valves according to a determined timing strategy based on at least one engine operating parameter.

Abstract: In order to operate an internal combustion engine with a turbocharger, a boost pressure prevailing downstream of a compressor (42) of the exhaust gas turbocharger and upstream of a cylinder intake port of the internal combustion engine is regulated to a predefined desired boost pressure value (PUT_SP). An actuation signal portion (DELTA_PWM_WG) of a controller for regulating the boost pressure to a desired boost pressure value (PUT_SP) is determined. A change in the turbocharger speed (DELTA_N_TCHA) associated with the actuation signal portion (DELTA_PWM_WG) of the controller is determined in accordance with the actuation signal portion (DELTA_PWM_WG) of the controller and an operating point of the internal combustion engine. A turbocharger speed limit (N_TCHA_MAX) is determined in accordance with the determined change in the turbocharger speed (DELTA_PWM_WG).

Abstract: The invention is intended to optimize the recovery of the residual energy contained in the exhaust gases of an internal combustion piston engine by means of a turbocharger group, in which each cylinder (1) from which the combustion gases escape through the exhaust pipe (5) is equipped with a turbine (7), and the volume (5) between the exhaust valve (3) and the inlet of the turbine (7), detrimental to the efficiency thereof, is minimized by the attachment of the turbine directly on the cylinder head of the engine without the intermediary of a collector and, the counter-pressure acting on the piston of the cylinder (1) during its exhaust upstroke is minimized owing to an adjustment of the turbine pressure by means of an additional exhaust valve (4), called a “dynamic discharge valve”, optionally equipped with a downstream throttle valve (8) in order to continuously adjust the corresponding flow rate and, consequently, the pressure of the turbine unless the control of the dynamic discharge valve (4) is not varia

Abstract: The subject is to efficiently detect the sticking of changeover valves for realizing a plurality of supercharging modes in a vehicle provided with a plurality of superchargers, and also to realize preferable fail-safe in cases where the sticking is detected. In a vehicle, which is provided with: a primary turbo and a secondary turbo, each of which is of an exhaust driven type; an exhaust changeover valve and an intake changeover valve, which are placed in a secondary exhaust passage and a secondary intake passage corresponding to the secondary turbo, respectively; and an intake bypass valve placed in an intake bypass passage, an ECU sets the opening/closing state of each changeover valve to an opening/closing state corresponding to a twin turbo mode at the time of engine stop, and it uses the drive control of each changeover valve which is necessitated in the transition to a single turbo mode at the engine start, thereby performing the sticking detection of the changeover valve at the same time.

Abstract: An internal combustion engine having a reciprocating multi cylinder internal combustion engine with multiple valves. At least a pair of exhaust valves are provided and each supply a separate power extraction device. The first exhaust valves connect to a power turbine used to provide additional power to the engine either mechanically or electrically. The flow path from these exhaust valves is smaller in area and volume than a second flow path which is used to deliver products of combustion to a turbocharger turbine. The timing of the exhaust valve events is controlled to produce a higher grade of energy to the power turbine and enhance the ability to extract power from the combustion process.

Abstract: A method is provided for operating a turbocharger. The method includes sensing a parameter indicative of a speed of a turbocharger and a parameter indicative of an engine speed. The method also includes determining a first desired engine speed based on the speed of the turbocharger, the engine speed, and a maximum desired speed of the turbocharger. The method further includes regulating a flow of fuel to an engine based on the first desired engine speed.

Abstract: The purpose of the present invention is providing a supercharging system which uses both of a mechanism such as VN or the like and an electric motor generating an assist force while making the supercharger operate smoothly when the assist by the electric motor is stopped. The system controls the electric motor in a feedback manner so that enough assist force is generated (FIG. 2A and FIG. 2B) while controlling the VN in an open manner (FIG. 2D) until status of the supercharger reaches target status (time t1) when an accelerator requirement arises in a low revolution region. The control of the electric motor is changed to an open control, and the control of the VN is changed to a feedback control, respectively, at time t1. The open control of the electric motor is continued so that necessary complement torque occurs until time t2. After time t2, the system maintains the target status only by the feedback control of the VN.

Abstract: A sequential-type, two-stage supercharging system (1) having a high-pressure-stage turbocharger (6) and a low-pressure-stage turbocharger (5), in which high-pressure-stage exhaust gas bypass passages (6d, 6e) for bypassing a high-pressure-stage turbine (6t) is formed by both the first bypass passage (6d) having a small-diameter valve (6f) and the second bypass passage (6e) having a large-diameter valve (6g) with a diameter greater than that of the small-diameter valve (6f). The effective valve area of the small-diameter valve (6f) is set to 9.5%-26.5% of the passage cross-sectional area required when exhaust gas is at its maximum total flow rate. This allows, in medium speed/medium load operation, fine EGR rate control and air-fuel ratio control.

Abstract: A multistage exhaust turbocharger is easily mountable in a narrow engine compartment of a vehicle by simplifying its construction and reducing its bulk. The multistage exhaust turbocharger has a high-pressure stage turbocharger and a low-pressure stage turbocharger. A cover of the high-pressure stage turbocharger has a compressor inlet passage, a bypass inlet passage, a switching aperture between the passages to be opened and closed by a valve body of the compressor bypass valve device, and a bypass outlet pipe part connecting to the bypass inlet passage to introduce bypass air passed through the aperture opened by the bypass valve to the compressor bypass channel which is to be connected to the bypass outlet pipe part.

Abstract: An internal combustion engine (100) includes an intake manifold (106) and at least one exhaust manifold (108). A first compressor (120) that is operably associated with a first turbine (128) has a first air inlet (126) and a first air outlet (118). The first air inlet (126) is adapted to admit air into the first compressor (120), and the first air outlet (118) is fluidly connected to the intake manifold (106). The first turbine (128) fluidly communicates with a tailpipe (138). A second compressor (124) is operably associated with a second turbine (160) and has a first tributary fluid inlet (152), a second tributary fluid inlet (154), and a second fluid outlet (122). The first tributary fluid inlet (152) is fluidly connected to the tailpipe (138) at a junction (147), the second tributary fluid inlet (154) is adapted to admit air into the second compressor (124), and the second fluid outlet (122) is fluidly connected to the intake manifold (106).