Abstract: A turbine shroud for a gas turbine engine includes a metallic support ring and a ceramic blade track. The blade track is formed from a plurality of blade track segments including dovetail posts. The dovetail posts are inserted through apertures in the support ring and are coupled to the support ring by segment retainers coupled to the dovetail posts providing a retention system for the ceramic blade track.

Abstract: A turbine component having a low residual stress ferromagnetic damping coating. The ferromagnetic damping coating may include a ferromagnetic damping material applied in at least partially molten powder form, which may be directed at a surface of the substrate at an application velocity so that it causes partial plastic deformation of the surface while adhering to the surface of the substrate and solidifying in less than 3 seconds to create a ferromagnetic damping coating, resulting in a coated substrate. The ferromagnetic damping coating has a balanced coating residual stress, including a tensile quenching stress component and a compressive peening stress component. The balanced coating residual stress is within a range of ±50 MPa without having to subject the coated substrate to a high temperature annealing process. The resulting coated substrate exhibits a high damping capacity.

Abstract: A method for forming three-dimensional anchoring structures on a surface is provided. This method may result in a thermal barrier coating system exhibiting enhanced adherence for its constituent coatings. The method involves applying a first laser beam (20) through a first portion (7) of a multi-core fiber (4) to a surface (12) of a solid material (14) to form a liquefied bed (16) on the surface (12) of the solid material (14), then applying a pulse of laser energy (24) through a second portion (6) of the multi-core fiber (4) to a portion of the liquefied bed (16) to cause a disturbance, such as a splash (28) of liquefied material outside the liquefied bed (16). A three-dimensional anchoring structure (30) may thus be formed on the surface (12) upon solidification of the splash (28) of the liquefied material.

Abstract: An aircraft engine including: a stator; a main shaft; a first rotor; a second rotor; a transmission mechanism; a first electrical apparatus supported by the first rotor and a second electrical apparatus supported by the second rotor; at least one first field winding supported by the stator; a control unit configured to circulate direct electric current in the first field winding; at least one first armature winding supported by the first rotor and connected to the first electrical apparatus and at least one second armature winding supported by the second rotor and connected to the second electrical apparatus.

Abstract: A propeller rotor has a hub mounting a plurality of blades. A counterweight is movably mounted on the blade. A pitch change mechanism for changing an angle of incidence of an airfoil is associated with each of the blades. The counterweight twists the blades toward an increased pitch direction should the pitch change mechanism fail. A stop member stops rotation of the counterweight as the blade moves to a feather position.

Abstract: The present application provides a turbine shroud cooling system for a gas turbine engine. The turbine shroud cooling system may include a number of variable area cooling shrouds with tuning pins and a number of fixed area cooling shrouds with anti-rotation pins. The variable area cooling shrouds may include modulated cooling shrouds. The fixed area shrouds may include non-modulated shrouds.

Abstract: Transition duct assemblies for turbine systems and turbomachines are provided. In one embodiment, a transition duct assembly includes a plurality of transition ducts disposed in a generally annular array and comprising a first transition duct and a second transition duct. Each of the plurality of transition ducts includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of each transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct assembly further includes an aerodynamic structure defined by the passages of the first transition duct and the second transition duct. The aerodynamic structure includes a pressure side, a suction side, and a trailing edge, the trailing edge having a modified aerodynamic contour.

Abstract: A limit stop device for limiting an adjustment path of a mobile component relative to a stationary component may include a sleeve body configured to be inserted into an opening formed in the stationary component. The sleeve body may include a retaining segment disposed in the interior of the opening. A core body may be disposed in the interior of the sleeve body and be configured to radially brace the retaining segment against an inner wall of the stationary component thereby axially fixing the sleeve body on the stationary component. A stop surface may protrude into the adjustment path of the mobile component and be configured to limit the adjustment path of the mobile component.

Abstract: A system includes a gas turbine system model configured to model a turbine system operational behavior of a gas turbine system, and a shaft contribution model (SCM) including a bottoming cycle performance (BCP) model configured to model a bottoming cycle behavior of a bottoming cycle system. The gas turbine system model is configured to receive a SCM output from the SCM and to use the SCM output to control an actuator. The actuator is operatively coupled to the gas turbine system.

Abstract: A method for performing a visual inspection of a gas turbine engine may generally include inserting a plurality of optical probes through a plurality of access ports of the gas turbine engine. The access ports may be spaced apart axially along a longitudinal axis of the gas turbine engine such that the optical probes provide internal views of the gas turbine engine from a plurality of different axial locations along the gas turbine engine. The method may also include coupling the optical probes to a computing device, rotating the gas turbine engine about the longitudinal axis as the optical probes are used to simultaneously obtain images of an interior of the gas turbine engine at the different axial locations and receiving, with the computing device, image data associated with the images obtained by each of the optical probes at the different axial locations.

Abstract: According to the present invention, a wind turbine generator system is provided which can not only remove the influence of salt damage in case the system is established off-shore, but even if the facility becomes larger, which can also cool equipment and the generator provided in the tower and can reduce the possibility of decreasing power generation efficiency.

Abstract: Length adjustable braces (56, 56A-D) attached between a gas turbine exhaust diffuser (40) and an exhaust casing (34) along a horizontal joint (50) between upper and lower halves (40A, 40B) of the outer diffuser shell. Brace lengths are adjusted to align bolt holes (52A, 52B) in respective bolt bosses (43A, 43B) on the upper and lower halves of the shell. The braces may be turnbuckles (56, 67) welded to or releasably attached at one end to the shell and at the other end to the casing. Exemplary fittings on the diffuser shell and casing for the brace ends may be clevis fittings (62) or eye fittings (72). The fittings may be configured to support both tension (58) and compression (59) of each brace. Two opposed fittings (70A, 70B) across the joint may be configured for insertion of a respective clevis bolt (63A, 63C) in both fittings from the same side.

Abstract: Aspects of the disclosure generally provide a heat engine system and a method for regulating a pressure and an amount of a working fluid in a working fluid circuit during a thermodynamic cycle. A mass management system may be employed to regulate the working fluid circulating throughout the working fluid circuit. The mass management systems may have a mass control tank fluidly coupled to the working fluid circuit at one or more strategically-located tie-in points. A heat exchanger coil may be used in conjunction with the mass control tank to regulate the temperature of the fluid within the mass control tank, and thereby determine whether working fluid is either extracted from or injected into the working fluid circuit. Regulating the pressure and amount of working fluid in the working fluid circuit selectively increases or decreases the suction pressure of the pump to increase system efficiency.

Abstract: A steam turbine plant of one embodiment includes a boiler to change water into steam, an upstream turbine including plural stages of rotor vanes and plural stages of stator vanes and to be driven by the steam from the boiler, a downstream turbine including plural stages of rotor vanes and plural stages of stator vanes and to be driven by the steam from the upstream turbine, a condenser to change the steam exhausted from the downstream turbine into water, a collector to collect water from, for example, the steam which exists upstream of an inlet of the final-stage rotor vane in the upstream turbine, and a collected matter path to cause collected matter in the collector to flow into, for example, the steam between an outlet of the final-stage rotor vane of the upstream turbine and an inlet of the final-stage rotor vane of the downstream turbine.

Abstract: Methods of sequestering toxin particulates are described herein. In a primary processing chamber, a carbon source of toxin particulates may be combined with plasma from three plasma torches to form a first fluid mixture and vitrified toxin residue. Each torch may have a working gas including oxygen gas, water vapor, and carbon dioxide gas. The vitrified toxin residue is removed. The first fluid mixture may be cooled in a first heat exchange device to form a second fluid mixture. The second fluid mixture may contact a wet scrubber. The final product from the wet scrubber may be used as a fuel product.

Abstract: A split cycle phase variable reciprocating piston spark ignition engine comprising a compressor unit having a compression chamber adapted to carry out the intake and compression strokes of a four stroke engine cycle, a power unit having an expansion chamber adapted to carry out the expansion and exhaust strokes of a four stroke engine cycle, a crossover gas passage for transferring compressed gas from the compression chamber to the expansion chamber, an expansion chamber volume modifier to provide nearly full load like combustion chamber condition at all the engine load conditions by means of modifying volume and shape of the expansion chamber, a phase altering mechanism for altering phase relation between the compressor unit and the power unit as a function of engine load variation, an electronic control unit for providing control commands for various electrically operated actuators and motors.

Abstract: A variable valve mechanism for an internal combustion engine includes a control shaft and a cam. The control shaft is configured to change a maximum lift amount of an engine valve according to displacement of the control shaft. The cam is configured to displace the control shaft in the axial direction due to rotation of the cam. The cam surface includes change zones and retention zones. Respective lengths of the retention zones in a rotation direction of the cam is set such that respective length of the retention zones in the rotation direction increases as the maximum lift amount retained by the retention zones increases.

Abstract: An iron-based alloy includes, in weight percent, carbon from about 2 to about 3 percent; manganese from about 0.1 to about 0.4 percent; silicon from about 0.3 to about 0.8 percent; chromium from about 11.5 to about 14.5 percent; nickel from about 0.05 to about 0.6 percent; vanadium from about 0.8 to about 2.2 percent; molybdenum from about 4 to about 7 percent; tungsten from about 3 to about 5 percent; niobium from about 1 to about 3 percent; cobalt from about 3 to about 5 percent; boron from zero to about 0.2 percent; and the balance containing iron and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.

Abstract: An engine, such as a variable displacement engine, has a camshaft retainer. The camshaft retainer has a cap adapted to cooperate with a carrier to support first and second overhead camshafts for rotation. The retainer cap forms a housing for a camshaft journal bearing. The retainer cap also forms a retainer land defining an open channel adapted to provide a jet of lubricating fluid from the bearing housing to externally lubricate a cam. The retainer land is adapted to mate with a sealing land of the carrier to enclose the open channel.

Abstract: A method of purifying NOX contained in exhaust gas, the method including a first NOX purification method and a second NOX purification method, wherein the first NOX purification method and the second NOX purification method include injecting hydrocarbons into an exhaust gas passage at predetermined feed intervals, wherein in the first method, the injected hydrocarbons are partially oxidized and an air-fuel ratio flowing into an exhaust purification catalyst is lean, and in the second method, the injection of the hydrocarbons occurs at intervals longer than the predetermined feed intervals in the first method, and an air-fuel ratio is switched from lean to rich.

Abstract: A reductant delivery system is provided for delivery of reductant to an engine exhaust aftertreatment system that is heated during cold temperature conditions. A heat exchange fluid flows through a heat exchange circuit that provides a flow path from the heat source to the doser, from the doser to the reductant storage tank, and from the reductant storage tank to the heat source. A control valve controls the flow of the heat exchange fluid in the heat exchange circuit so that at least one heat exchange cycle includes a circulation period that increases the temperature of the reductant in the doser and storage tank and a termination period where circulation is stopped until reductant temperature in the doser reaches a lower limit.

Abstract: The present invention provides a highly durable, electrically heated catalytic converter having a relatively simple structure while its inner tube is curved toward the central axis, wherein an insulation layer formed on the inner tube is less susceptible to cracking and peeling even when the inner tube is subjected to temperature changes or temperature gradients.

Abstract: A control apparatus is disclosed for a diesel exhaust fluid injector located in an exhaust pipe of a diesel internal combustion engine. The control apparatus includes an electronic control unit configured to: energize a solenoid of the injector to perform a diesel exhaust fluid injection; determine an electric voltage value indicative of the electric voltage applied to the injector solenoid during the diesel exhaust fluid injection; determine an electric current value indicative of the electric current flowing through the injector solenoid during the diesel exhaust fluid injection; calculate an electric resistance value of the injector solenoid as a function of the determined electric voltage value and the electric current value; and estimate an injector temperature value as a function of the calculated electric resistance value.

Abstract: A catalyst unit may include a carrier that channels may be formed from a front surface thereof to a rear surface thereof, and plugs that closes the channels that may be formed along an edge portion of the front surface except a central portion of the front surface, wherein a coating layer may be not formed in the channels that the plugs may be disposed and a coating layer may be formed along the remaining opened channels.

Abstract: An exhaust treatment device is disclosed. The exhaust treatment device has a compact configuration that includes integrated reactant dosing, reactant mixing and contaminant removal/treatment. The mixing can be achieved at least in part by a swirl structure and contaminant removal can include NOx reduction.

Abstract: An exhaust heat recovery control device includes a recovered heat adjusting unit configured to adjust an amount of heat recovered of exhaust gas by an exhaust heat recoverer recovering heat of exhaust gas and a control unit configured to control the recovered heat adjusting unit so as to prevent or suppress freezing in an exhaust pipe based on a traveling history of a vehicle on which the exhaust heat recovery control device is mounted when the freezing in the exhaust pipe is predicted.

Abstract: A heat exchange device having a first media channel for a first medium and a second media channel for a second medium is further refined in that, in at least one section of the heat exchange device, a third media channel for a transfer medium is arranged between the first media channel and the second media channel, so that the heat transfer from the first medium to the second medium takes place via the transfer medium.

Abstract: The present invention provides a diesel engine capable of preventing a PM accumulation amount from increasing excessively. If DOC inlet exhaust gas temperature (“IEGT”) does not reach a predetermined value T0, a control unit carries out air intake amount feedback control (“AIAFC”), and a target value of intake throttling is set to a predetermined air intake amount. If the DPF regenerating processing is not started even if elapsed time reaches a predetermined value t after AIAFC is started in a state where the DOC IEGT does not reach the predetermined value T0, the control unit changes AIAFC to exhaust gas temperature feedback control (“EGTFC”). In EGTFC, the control unit changes a target value of intake throttling to a predetermined DOC IEGT T0. If application of a load exceeding a predetermined amount is detected before the DOC IEGT reaches the predetermined value T0, the control unit returns EGTFC to AIAFC.

Abstract: An exhaust gas treatment system for an internal combustion engine may have a reductant delivery system with a controller that performs period diagnostics to determine whether there is a blockage in the reductant delivery system. The diagnostic procedure may include sampling first and second pressures at first and second operating conditions, respectively, and then comparing the first pressure differential between the first and second pressures with one or more threshold pressure differentials to determine whether system components such as a dosing line and an injector are at least partially blocked. If such a test is not conclusive, it may be repeated at a third and fourth operating conditions to provide a second pressure differential. The offset between the first and second pressure differentials may also be used to help diagnose where a blockage in the system resides.

Abstract: A radiant heat discharge arrangement for use with a internal combustion engine is disclosed. The internal combustion engine may have an outlet manifold. The radiant heat discharge arrangement may have a cover configured to over the outlet manifold with a clearance between the cover and the outlet manifold. The cover may have at least one outlet opening. The radiant heat discharge arrangement may also have an air duct having at least one air inlet fluidly connected to the at least one outlet opening of the cover. The air duct may also have an air outlet. Further, the radiant heat discharge arrangement may have a fan fluidly connected to the air outlet.

Abstract: A cooling device for electric equipment includes a cooling unit for cooling an inverter element as a heat source. The cooling unit has a surface on which the inverter element is provided and a back surface disposed on a back side of surface, and includes a heat mass for transferring heat generated by the inverter element, an air-cooling fin provided on the back surface and radiating heat transferred through the heat mass, and an air-conditioner coolant pipeline provided on the surface and forming a coolant passage through which the coolant for vehicle cabin air-conditioning flows. With such configuration, a cooling device for electric equipment excellent in the cooling efficiency is achieved.

Abstract: A motor vehicle coolant pump for supplying coolant to an engine includes a two-part pump housing comprising a pump rotor housing part and a body housing part. The pump rotor housing part comprises a first mounting flange, and the body housing part comprises a second mounting flange which together fix the housing parts with respect to each other and allow a mounting of the housing parts on each other in every rotary position. A pump rotor is arranged in the pump rotor housing part. An axial coolant inlet and a tangential coolant outlet are provided on the pump rotor housing part. A rotary fixation comprises a recess at the pump rotor housing part and a nose which engages in the recess. The rotary fixation allows the pump rotor housing part and the body housing part to be mounted with respect to each other in only one single rotational angle.

Abstract: A cooling fan control unit, in response to an operation performed at the rotation direction selector switch to select a reverse rotation setting while the cooling fan is rotating forward, lowers a relief pressure setting at the variable relief valve to a predetermined lower limit value over a predetermined length of time, and once the discharge pressure at the hydraulic pump detected by the pressure sensor is lowered to a predetermined switch-over pressure, executes control so as to switch the direction of flow of pressure oil to the hydraulic motor to the reverse direction by switching the direction switching valve and raises the relief pressure setting at the variable relief valve to a reverse rotation pressure setting, at which the hydraulic motor rotates in the reverse direction, over a predetermined length of time.

Abstract: Methods and systems are providing for improving engine coolant level estimation to reduce engine overheating. The level of fluid in a coolant overflow reservoir is inferred based on the fluid level in a hollow vertical standpipe fluidically coupled to the reservoir at top and bottom locations, while the fluid level in the standpipe is estimated based on output from an ultrasonic signal transmitted by a sensor positioned in a recess at the bottom of the vertical standpipe. Sensor power usage is optimized based on the ratio of first order and higher order harmonic echo times in the raw data set generated by the sensor.

Abstract: Methods and systems are provided for adjusting a compressor recirculation valve in response to condensate forming conditions in a charge air cooler (CAC). In one example, a compressor recirculation valve may be opened in response to an induction pressure greater than a threshold pressure when the induction pressure is greater than required to produce a manifold pressure required for a torque demand. Further, a wastegate may be opened to further reduce the induction pressure during certain driving conditions.

Abstract: A method of introducing additives to an air intake system of an engine in order to overcome one or more of the various problems created by formulation of additives in fuels. The method controls at least one of the amount, aerosol particle size and timing of introduction of additives based on information relevant to operation of the engine. The introduced additives form an air-additive mixture and are carried by the airflow in the air-intake system to the combustion chamber of the engine. Another aspect of the invention is an additive introduction system that includes one or more containers for additives, a control system for determining at least one of the amount, aerosol particle size and timing of introduction of the additives, and a device to introduce the additives into the air intake system under the control of the control system.

Abstract: The method and the apparatus described are used for generating electrical energy in a combined system comprising a power plant and a low-temperature air separation unit. A feed air stream is compressed in a main air compressor, cooled, and introduced into a distillation column system having a high-pressure column and a low-pressure column. A first oxygen-enriched stream from the distillation column system is introduced into the power plant. In a first operating mode, cryogenic liquid from the distillation column system is introduced into a liquid tank and is stored there at least in part. In a second operating mode, stored cryogenic liquid is removed from the liquid tank and introduced into the distillation column system. A second process fluid from the distillation column system is heated and then actively depressurized in a hot expansion turbine.

Abstract: A component, especially contrived and designed for being used in a turbomachine, includes a high-temperature coating being arranged above a base of the component. The base has at least one structural element for connecting it to the high-temperature coating, with the cross-section of the at least one structural element having at least three different widths, i.e. a base width at the lower end of the at least one structural element, a center width above it, and a tip width above that, where on average the center width is greater than or equal to the base width, but less than four times the base width, in particular less than or equal to three times the base width.

Abstract: An air-to-air cooler has a heat exchanger integrated to a housing. A first passage extends through the housing for directing a flow of cooling air through the heat exchanger. A second passage extends through the housing for directing a flow of hot air to be cooled through the heat exchanger. The first passage has a cooling air outlet tube disposed downstream of the heat exchanger. The cooling air outlet tube extends across the second passage between the heat exchanger and a hot air inlet of the second passage. The hot air inlet is disposed to cause incoming hot air to flow over the cooling air outlet tube upstream of the heat exchanger. An ejector drives the flow of cooling air through the first passage of the air-to-air cooler. A portion of the hot air flow may be used to drive the ejector.

Abstract: An intake air cooling system 100 for a gas turbine 18 is provided with: an intake duct 12 for leading intake air from an intake-air inlet 22 to a compressor 14 of the gas turbine, the intake duct having a vertical duct 12c and a manifold part 12d disposed on a downstream side of the vertical duct; a cooling part 26 provided in the intake duct to cool the intake air by heat exchange with a cooling medium which is introduced from an outside; a filter part 42 provided on an inlet side of the manifold part to remove impurities contained in the intake air introduced through the vertical duct; and a drain catcher 110 constituted by a gutter member provided immediately above the filter part along inner wall surfaces 12c1, 12c2 of the vertical duct, the drain catcher being configured to collect drain water flowing along the inner wall surfaces of the vertical duct.

Abstract: A blind installation pin assembly for a gas turbine engine includes a pin that defines a bore. A paddle mounted to an end of the pin to pivot about a paddle axis between an install position and a lock position. A T-bolt that passes through the bore, a crosspiece of the T-bolt selectively engageable with the paddle.

Abstract: One embodiment of the present invention is a turbine nozzle segment for a turbine section of a gas turbine. The turbine nozzle segment includes an inner platform, an outer platform and an airfoil that extends therebetween. The airfoil includes a forward portion and an aft portion that is disposed downstream from the forward portion. The turbine nozzle segment further includes a fuel injection insert that extends between the inner platform and the outer platform downstream from the aft portion of the airfoil. The fuel injection insert includes a fuel circuit that extends within the fuel injection insert, and a plurality of fuel injection ports disposed within the fuel injection insert. The plurality of fuel injection ports provide for fluid communication with the fuel circuit.

Abstract: A method including providing a wet algae material having been subjected to a refinement process without a water separation phase; supplying the wet algae material including a water fraction and an algae-grown biofuel to a turbine engine; and operating the turbine engine with the wet algae material where a retained portion of the water fraction is retained in the wet biofuel during a manufacturing process not including a dehydration step and includes an amount sufficient to reduce generation of a quantity of nitrogen oxides, and where the turbine engine can further include a combustor capable of combusting the wet biofuel.

Abstract: Apparatus for controlling a turbine aircraft engine may include apparatus to determine an amount of secondary power extraction from the engine, a secondary load processor configured to receive and condition secondary power extraction data. An electronic engine controller (EEC) may be configured to receive secondary load data from the secondary load processor and produce commands to open bleed-air valves of the engine, said commands being based on the secondary load data.

Abstract: A system and method of adaptively synchronizing the performance margin of a multi-engine system includes continuously, and in real-time, determining the performance margin of a first engine and the performance margin of the second engine. A difference between the performance margins of the first and second engines is calculated, and the first and second engines are controlled to attain a predetermined difference between the performance margins of the first and second engines.

Abstract: A fuel control system and method for providing fuel to an internal combustion engine are provided. The fuel control system generally includes at least one valve device structured to deliver a fuel supply to the engine, a first fuel source structured to provide a primary fuel to the valve device, a second fuel source structured to provide an alternate fuel to the valve device, and an electronic controller structured to control the valve device. The electronic controller controls the valve device as a function of various data to selectively deliver the primary fuel and the alternate fuel to generate a fuel supply, e.g. as a mixture of the two fuels. The data used to control the fuel supply may include GPS data, engine data, environmental data, and/or other operational data.

Abstract: Methods and systems are provided for improving spark robustness. Spark ignition dwell commands are adjusted based on the fuel fraction delivered via direct injection relative to port injection. The approach allows ignition output to better match the ignition requirement of the given fuel combination.

Abstract: Provided is a control apparatus for an internal combustion engine which can favorably achieve a good balance between the prevention of an excessive increase in the piston temperature and the prevention of deterioration of various performances of the internal combustion engine as a result of execution of abnormal combustion suppression control, even when abnormal combustion occurs continuously or substantially continuously over a plurality of cycles. An in-cylinder pressure sensor (34) is provided to obtain the in-cylinder pressure P of an internal combustion engine (10). When continuous pre-ignition is detected using the in-cylinder pressure sensor (34), the control apparatus makes it more difficult for continuous pre-ignition suppression control to be executed when the Pmax at the time of pre-ignition is low than when the Pmax at the time of pre-ignition is high.

Abstract: The control apparatus includes a transient-state ignition-timing correction unit in which, in order to set a change in ignition timing made coincident with a change in an internal EGR temperature and also made coincident with the strength of the transient when the transient operating state occurs, an ignition-timing correction-coefficient during the transient operating state and after the transient operating state is calculated in accordance with an internal EGR temperature discrepancy-degree derived from the internal EGR temperature and a steady-state exhaust-gas temperature, and with transient strength derived from a magnitude of change in the operating state and an elapse time since the transient operating state has started, and the ignition timing is corrected by a transient-state ignition-timing correction-coefficient.

Abstract: Abnormality diagnosis device for a variable valve mechanism configured to open an exhaust valve even during an intake stroke and capable of selecting a first mode wherein the exhaust valve only opens during an exhaust stroke, or a second mode wherein the exhaust valve opens during both an exhaust stroke and an intake stroke. The abnormality diagnosis by the device determines the mechanism is abnormal when a difference between an exhaust gas returning amount calculated to recirculate from an exhaust passage into a cylinder in the second mode based on intake air amounts in the first and second modes, and an exhaust gas returning amount estimated to recirculate from an exhaust passage in the second mode based on an exhaust gas pressure, exceeds a diagnosis threshold value. The higher an exhaust gas pressure is, the larger an exhaust gas returning amount is estimated to be.