Abstract: The present application provides a method of evaluating fatigue damage in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors and based upon the operating parameters, determining: a run time from start-up until the turbine reaches X percent load and a start-up temperature transient from start-up until the turbine reaches X percent load, and calculating: a run time ratio of the determined run time until the turbine reaches X percent load to a predetermined run time, a start-up temperature ratio of the determined start-up temperature transient to a predetermined start-up temperature transient, and a fatigue severity factor by averaging the run time ratio and the start-up temperature ratio. Based upon the determined fatigue severity factor, altering one or more of the operating parameters and/or initiating repair procedures.

Abstract: The present application provides a method of evaluating spindle component wear in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors, wherein the operating parameters may include spindle position from which a number of spindle strokes and an accumulated spindle distance may be determined and temperature, generating a movement history based on the operating parameters, comparing the movement history to predetermined values, and altering one or more of the operating parameters and/or initiating repair procedures if the movement history exceeds predetermined values.

Abstract: The present application provides a method of evaluating valve spindle vibration in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors, wherein the operating parameters may include valve spindle vibration, comparing the valve spindle vibration to a predetermined value, and altering one or more of the operating parameters if the valve spindle vibration exceeds the predetermined value.

Abstract: The present application provides a method of evaluating inspection intervals in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors, wherein the operating parameters may include steam pressure, steam temperature, metal temperature, and valve spindle position, comparing one or more of the operating parameters to predetermined values, and shortening an inspection interval if the one or more of the operating parameters exceed the predetermined values for longer than a predetermined duration.

Abstract: The present application provides a method of evaluating insulation quality in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors, wherein the operating parameters may include casing temperatures and insulation temperatures, comparing the casing temperatures and the insulation temperatures to predetermined casing and insulation values, and altering one or more of the operating parameters and/or initiating repair procedures if the casing temperatures fall below the casing predetermined values and/or the insulation temperatures exceed the insulation predetermined values.

Abstract: The present application provides a method of evaluating valve tightness in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors, opening a first valve and closing a second valve, closing the first valve, determining a pressure decay time between the first valve and the second valve, determining a stable value of pressure between the first valve and the second valve, comparing the pressure decay time and the stable value of pressure to predetermined values, and altering one or more of the operating parameters and/or initiating repair procedures if the pressure decay time and/or the stable value of pressure is increasing and/or exceeds the predetermined values.

Abstract: The present application provides a method of evaluating valve conditions in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors, wherein the operating parameters may include steam temperatures determined over time and steam pressure, determining a steam chemistry, a throttling history, and a piping material, determining a probability of valve erosion based upon the steam temperatures determined over time, the steam chemistry, the throttling history, and the piping material, and altering one or more of the operating parameters and/or initiating repair procedures based upon the determined probability.

Abstract: The present application provides a method of evaluating valve spindle leakage and guide deformation in a turbine by a data acquisition system. The method may include receiving a number of operating parameters from a number of sensors, generating a friction hysteresis curve based on the operating parameters, determining a friction characteristic based on the friction hysteresis curve, comparing the friction characteristic to previous friction characteristics, and altering one or more of the operating parameters and/or initiating repair procedures if the friction characteristic is increasing and/or exceeds a predetermined value.

Abstract: The present application provides a method of evaluating valve creep damage in a turbine by a data acquisition system. The method may include the steps of receiving a number of operating parameters from a number of sensors including steam temperatures and steam pressures about the valve over time, generating a design material model for the valve, determining an indicator for consumed creep lifetime based on the steam temperature and steam pressures about the valve over time as compared to the design material model, and altering one or more of the operating parameters and/or initiating repair procedures based upon the consumed creep lifetime indicator.

Abstract: An engine health monitoring system includes an engine component having a sensor system configured to monitor at least one parameter of the component. An autonomous monitoring system is coupled to the sensor system and is configured to receive and store the at least one monitored parameter while an engine controller is unpowered. The engine controller is communicatively coupled to the autonomous monitoring system.

Abstract: A vane (54) for a turbomachine, comprises an aerodynamic profile (61) formed from a body (70) made from a first material, and an add-on part (74) fixed to the body (70) by brazing and made from a second material. The add-on part (74) is housed in a recess (72) formed in a median part of an end part (73) of the body (70), between extreme parts (73A, 73B) of the end part, such that the add-on part (74) forms a median portion of the leading edge (62) of the aerodynamic profile (61). The second material has a coefficient of linear thermal expansion along the direction of the leading edge greater than that of the first material, at a normal operating temperature of the vane (54), which reduces risks of cracks appearing in the aerodynamic profile (61).

Abstract: The present disclosure is directed to a rotating component for a turbine engine. The rotating component defines a surface and includes a heat pipe positioned on the surface of the rotating component or within the rotating component. The heat pipe includes a working fluid and an outer perimeter wall.

Abstract: A turbine engine is provided with a longitudinal rotation axis having at least one shaft with a radial axis, in particular a pitch change system for the blades of a propeller, said shaft traversing a radial passage of a substantially cylindrical case around the longitudinal axis. The turbine engine includes an annular oil guiding device around the radial shaft. The device has first and second annular parts nested in one another and secured to one another by hooping. The first part is secured by hooping to the radial shaft, and the second part is configured so as to be separated from the first part under the action of a force oriented along the radial axis and exerted on the second part by a member of the turbine engine forming a stop during a radial movement of the radial shaft.

Abstract: A turbine includes a turbine rotor, a stationary body that covers the turbine rotor, and a diffuser provided on an outlet side of the stationary body. Last-stage moving blades of the turbine rotor include blade sections and covers provided at distal ends of the blade sections. The diffuser is formed such that an outer circumferential surface of an inlet section is small in diameter with respect to an inner circumferential surface of an outlet section of the stationary body and a circumferential wall section of the inlet section at least partially overlaps the covers in a radial direction when viewed from the axial direction. An annular gap space between the stationary body and the covers faces a space on an outer side of an outer circumferential surface of the diffuser when viewed from the axial direction.

Abstract: A gas turbine, including: a combustion chamber; a high-pressure turbine with a first turbine guide vane ring that is arranged downstream of the combustion chamber, wherein the first turbine guide vane ring has a plurality of turbine nozzle guide vane segments that respectively include at least one guide vane, an outer platform, and an inner platform; and an outer housing. Provision is made that the turbine nozzle guide vane segments are fixed in the radial direction at the outer housing, wherein occurring radial loads are transferred into the outer housing. The invention further relates to a method for attaching a turbine nozzle guide vane segment of a gas turbine.

Abstract: The invention relates to a positioning element for a guide vane arrangement of a guide vane stage of a gas turbine, with at least one base section curved in the peripheral direction; a plurality of uptake openings arranged next to each other in the peripheral direction on the base section, whose aperture axis runs substantially in the radial direction and which are designed to take up a respective radially inner guide vane section; a coupling section provided on the base section, which is or can be coupled to a seal carrier of a seal arrangement. According to the invention, it is proposed that at least one recess is provided in the base section, which is arranged between two neighboring uptake openings and runs from inside to outside at least in the radial direction.

Abstract: A gas turbine exhaust assembly includes an exhaust flow path configured to receive an exhaust flow from a gas turbine engine, the exhaust flow path defined by an inner hub and a radially outer wall. The gas turbine exhaust assembly also includes a plurality of vanes circumferentially spaced from each other and operatively coupled to the radially outer wall of the exhaust flow path, each of the plurality of vanes extending only partially toward the inner hub and terminating at an inner end of the vanes, the inner end defining an open portion.

Abstract: Methods and systems for reducing carbon dioxide emissions from a coal-fired power plant by using thermal energy from a non-carbon source to reduce the amount of electrical energy needed to reduce the moisture content of coal and increase the energy density of coal prior to combustion are provided. The system includes at least one non-carbon thermal energy source; a coal processing plant configured to reduce the moisture content of coal and produce an increased energy density beneficiated coal, wherein said at least one non-carbon thermal energy source is used to reduce an electrical need of the coal processing plant; and a coal-fired power plant configured to combust the increased energy density beneficiated coal thereby producing electricity on demand at an increased efficiency with reduced carbon dioxide emissions from the plant. The renewable energy source is selected from microwave, hydroelectric power, solar power, wind power, and/or wave power.

Abstract: Systems and methods to reduce the emissions of carbon dioxide associated with coal fired power plants by using electricity from a nuclear power plant to power a coal processing plant that reduces the moisture content of coal resulting in an increased energy density beneficiated coal are provided. The system includes a source of electricity from a nuclear power plant; a coal processing plant configured to reduce the moisture content of the coal by a beneficiation process to produce an increased energy density coal; and a coal-fired power plant configured to convert the increased energy density coal to electricity on demand at a higher efficiency with reduced emissions of carbon dioxide.

Abstract: A boiler including one or more evaporators, an economizer, and a low-temperature heat exchanger. The economizer is located on a downstream side of the most downstream evaporator which is an evaporator at the most downstream side among the one or more evaporators. The low-temperature heat exchanger is located on the downstream side of the economizer, has an inlet for receiving water from the outside, and is configured to heat the water introduced from the inlet and sent to the economizer with the combustion gas.

Abstract: A rocker arm includes a pivot portion that is journaled by a rocker arm shaft, a contact portion that projects from the pivot portion to a side of a valve cam, and a pressing portion that projects from the pivot portion to a side of a valve. While including a slipper projecting from the pivot portion in outer side in an axial direction to a side of a camshaft, an overhead valve actuation mechanism for the engine includes a stopper portion with which the slipper comes in contact when the rocker arm swings and reaches a predetermined position at a position opposing the slipper.

Abstract: An overhead valve actuation mechanism for an engine includes a camshaft that is rotatably supported by the cylinder head and includes one or a plurality of valve cams. The camshaft operates opening and closing of an intake valve and an exhaust valve via the valve cam. The only one camshaft is disposed within the one cylinder head. The camshaft has an axis center biased to a side of the exhaust valve with respect to a cylinder axis line as viewed from an axial direction of the camshaft.

Abstract: An overhead valve actuation mechanism for an engine includes a cylinder head, a camshaft that is rotatably supported by the cylinder head, includes one or a plurality of valve cams, and operates opening and closing of an air intake side or air exhaust side valve via the valve cam, a rocker arm that is swung by the valve cam of the camshaft and acts on the valve to open and close the valve, and a rocker arm shaft that is supported by the cylinder head and swingably supports the rocker arm. The rocker arm shaft includes a supporting portion supporting the rocker arm and a fixed shaft portion supported by the cylinder head. The supporting portion is formed such that a rotation axis of the rocker arm parallelly and slightly separates with respect to a center axis line of the fixed shaft portion.

Abstract: A system for actuating engine valves may include a valve bridge having a main event rocker interface portion, a first valve interface portion and a second valve interface portion extending in generally opposite directions from the main event rocker interface portion. The second valve interface portion may include an open end including a slot for receiving a bridge pin. The slot permits the valve bridge to be removed from the actuation system without removal of the main event rocker or other actuating components, such as an auxiliary rocker. The valve bridge can be removed from the valve train without requiring removal of other actuation system components, such as auxiliary rockers or main event rockers. A single valve bridge configuration can be used with different valve spans, which may occur among different cylinder sizes in a given engine family, or across different engine families.

Abstract: A camshaft phaser includes an input member; an output member defining an advance chamber and a retard chamber with the input member; a camshaft phaser attachment bolt which clamps the camshaft phaser to a camshaft, the camshaft phaser attachment bolt having a bolt valve bore extending along an axis. A valve sleeve is located coaxially within the bolt valve bore such that an annular clearance is provided radially therebetween. A valve spool is located coaxially within the valve sleeve such that the valve spool is moved coaxially between an advance position and a retard position. A compliant sealing ring radially between the bolt valve bore and the valve sleeve prevents fluid communication through the annular clearance axially between opposing axial sides of the sealing ring and isolates the valve sleeve from radial expansion of the camshaft phaser attachment bolt.

Abstract: Systems and methods for a cam phasing control system are provided. In particular, systems and methods are provided for a cam phasing control system that can be configured to control a first cam phase actuator and a second cam phase actuator and selectively switch the operation thereof between a regenerative mode and an oil pressure actuation mode.

Abstract: A camshaft phaser includes a stator having a plurality of lobes; a rotor coaxially disposed within the stator, the rotor having a plurality of vanes interspersed with the plurality of lobes defining a plurality of advance chambers and a plurality of retard chambers such that the plurality of advance chambers and the plurality of retard chambers are arranged in an alternating pattern and such that the rotor rotates within the stator from a full advance position to a full retard position; and a supply passage in continuous fluid communication with one of the plurality of advance chambers, the supply passage being in continuous fluid communication with an oil source.

Abstract: A system includes a rocker arm assembly for operative engagement with a first and second cam. The assembly includes a first arm for operatively engaging the first cam for a first desired lift profile, a second arm for operatively engaging the second cam for a second desired lift profile, where the second arm includes a latch to engage the second arm with the first arm. The latch is responsive to supplied oil pressure and release oil pressure to switch between lift profiles. The system includes the latch coupled to the supplied or released oil pressure to engage the arms before the first and second arms are engaged with the base circle portion of each of the respective first and second cams.

Abstract: A switching rocker arm for engaging a cam includes a first arm having a first end and a second end, and a first and a second side arm; a second arm disposed between the first and second side arms, having a first end and a second end, where the second arm is an inner arm. The second arm is pivotably secured adjacent its first end to the first arm adjacent the first end of the first arm. The rocker arm includes an over-travel limiter that limits pivoting motion of the first arm relative to the second arm, where the over-travel limiter is pivotally coupled to the outer arm and interacts with the inner arm.

Abstract: A method of regulating oil pressure within an engine assembly is provided. The engine assembly includes an oil pump configured to provide oil to an oil system of the engine assembly; a piston cooling jet configured to direct a jet of oil from the oil system towards a piston of an engine; and an electronic control valve configured to control the flow of oil to the piston cooling jet. The method includes operating the electronic control valve to provide a flow rate of oil above a threshold flow rate to the piston cooling jet when the engine assembly is operating above a threshold power output or engine running speed; and regulating the pressure of oil within the oil system when the engine assembly is operating below the threshold power output or engine running speed, by operating the electronic control valve.

Abstract: An invention refers to a lubricant injector, a lubrication system and a method for providing lubricant for a piston machine. The lubricant injector is provided with a lubricant inlet conduit and an outlet opening, through which a lubricant is supplied to an inner space to be lubricated of a piston machine. The outlet opening may be selectively opened and closed by means of a needle valve, which is actuated by a magnet coil. The lubricant injector has a flow sensor suitable for determining the quantity of lubricant delivered through the outlet opening.

Abstract: Disclosed is a lubricating apparatus including an oil supply pipe connected to a gearbox of a gearing device for transmitting turning force of a blowdown turbine in the turbo compound system to a crankshaft to supply oil into the gearbox, a first oil supply opening formed to be transpierced at the bearing housing of a first bearing rotatably supporting a shaft of an output gear for outputting turning force in the turbo compound system to supply oil supplied from the gearbox to the first bearing, a sub-supply pipe connected to a gear case in which the output gear is embedded to supply oil to the gear case, and a second oil supply opening formed to be transpierced at the bearing housing of a second bearing rotatably supporting the shaft of the output gear to supply oil supplied through the sub-supply pipe to the second bearing.

Abstract: Various systems and methods are provided for a lubricant filter. In one example, a method for a lubricant filter comprises indicating a condition of the filter based on a difference between a measured pressure differential and an expected pressure differential during select conditions in which all lubricant pumped by a pump upstream of the filter flows into the filter.

Abstract: An oil-gas separator assembly is provided, which includes a rotating separating section and a stationary filtering section. The rotating separating section includes: a rotating member provided with a through hole for an oil-gas mixture passing through; a rotating skeleton fixedly arranged at an outer side of the rotating member, wherein a rotating filter element is provided in the rotating skeleton for being rotated along with the rotating skeleton; a connecting pipe fixedly connected to an inner side of the rotating member; and a rotating impeller fixedly connected to the rotating member and located in the connecting pipe, wherein the rotating impeller is used for suctioning the oil-gas mixture into the oil-gas separator assembly. The stationary filtering section includes: a housing fitted with the connecting pipe; a stationary skeleton; and a vent hole provided on the housing, and an oil discharging hole provided at the bottom of the housing.

Abstract: An exhaust pipe structure has: an exhaust pipe through which exhaust from an engine flows; a communicating portion that is formed in a lower surface side of the exhaust pipe further toward a downstream side, in a direction of flow of the exhaust, than a catalyst device provided at the exhaust pipe, and that communicates an interior and an exterior of the exhaust pipe; and a porous body that is disposed at the communicating portion and that leads moisture, which is at the interior of the exhaust pipe, to the exterior of the exhaust pipe by capillary action.

Abstract: An improved system and method for treating exhaust emissions from a combustion engine is provided. The system provides improved arrangements for oxidizing particulate matter away from a particulate filter by utilizing elevated temperature exhaust manifold gases.

Abstract: Methods for evaluating a soot quantity accumulated in a selective catalytic reduction wash-coated particulate filter (SCRF) of an exhaust gas treatment system are provided, and include injecting reductant proximate the SCRF, determining one or more mapping values, computing a correction value of a soot quantity using a map correlating the one or more mapping values, detecting an apparent soot burning operating temperature, and correcting an estimated value of the soot quantity using the correction value in order to obtain an evaluated value of the soot quantity. The one or more mapping values can include a reductant injection quantity value, a NOx quantity value, a temperature value, and a mass flow value of an exhaust gas. The apparent soot burning operating temperature can comprise a temperature at which a ?P across the SCRF improperly implies an actual soot burning. Further provided are apparatuses for performing the disclosed methods.

Abstract: An internal combustion engine system includes a cylinder block with a plurality of cylinders, a gas intake manifold for providing at least air to the cylinder block and an exhaust gas manifold for exiting the exhaust gas from the cylinder block, wherein the exhaust gas manifold includes at least a main exhaust gas outlet and a waste gate exhaust gas outlet, wherein the main exhaust gas outlet is connected to a main exhaust gas pipe for guiding the exhaust gas to a main exhaust gas after treatment system and the waste gate exhaust gas outlet is connected to a waste gate exhaust gas pipe, and wherein the waste gate exhaust gas pipe is reconnected to the main exhaust gas pipe upstream of the main exhaust gas after treatment system and includes at least one waste gate exhaust gas after treatment unit, such as an oxidation catalyst such as a diesel oxidation catalyst, for catalytically treating the exhaust gas streaming through the waste gate exhaust gas pipe, and to a method for increasing the temperature in an i

Abstract: An exhaust aftertreatment system for purifying an exhaust gas feedstream from an internal combustion engine disposed to operate at a lean air/fuel ratio is described, and includes an oxidation catalyst disposed upstream of a low-temperature NOx adsorber. The oxidation catalyst includes a zeolite catalyst including a base metal, a noble metal, and a zeolite disposed on a substrate, and the low-temperature NOx adsorber includes a zeolite catalyst and a supported platinum group metal catalyst.

Abstract: Methods and systems are provided for expediting catalyst warm-up. In one example, a method may include flowing exhaust gas from an engine first through an emission control device and then through a turbine to rotate the turbine in a reverse direction, the rotation of the turbine in the reverse direction generating intake manifold vacuum for a vacuum consumer via a compressor coupled to the turbine. In this way, heat loss through a turbine may be avoided.

Abstract: Methods and systems are provided for expediting light-off of a catalyst during engine cold-start conditions by inhibiting rotation of the turbocharger shaft. In one example, a method may include inhibiting rotation of the turbocharger shaft during engine cold-start conditions until the catalyst is operating at a desired efficiency. The rotation of the shaft may be inhibited via either a passive or an active shaft locking mechanism.

Abstract: An engine system may include an engine, an intake line, a cylinder deactivation (CDA) device mounted at a portion of combustion chambers, a first exhaust manifold connected to combustion chambers mounted with the CDA device, a second exhaust manifold connected to combustion chambers without the CDA device, a first exhaust line flowing exhaust gas exhausted from the first exhaust manifold, a second exhaust line flowing exhaust gas exhausted from the second exhaust manifold, a main exhaust line to which the first exhaust line and the second exhaust line are joined, an exhaust gas processing device at which the main exhaust line is installed, a turbocharger mounted at the first exhaust line, an electric supercharger installed at the intake line to supply supercharged air to the combustion chamber and an electric compressor, and an air injection device supplying the fresh air to the second exhaust manifold or the second exhaust line.

Abstract: Provided is an exhaust purification system including: an NOx occlusion reduction type catalyst that is provided in an exhaust system of an internal combustion engine, and occludes NOx when an exhaust gas is in a lean state, and reduces the NOx when the exhaust gas is in a rich state; a regeneration control unit that executes a regeneration process of bringing the exhaust gas into a rich state to reduce the NOx occluded in the NOx occlusion reduction type catalyst; a storing unit that stores an exhaust lambda prediction value in advance when the regeneration process is executed; a reduction amount estimating unit that estimates an NOx reduction amount when the regeneration process is executed; and a prohibition unit that prohibits the execution of the regeneration process by the regeneration control unit when the estimated NOx reduction amount is less than a predetermined lower limit threshold.

Abstract: An injector having at least one heat dissipation element used for providing a highly conductive path for transferring heat away from a valve portion of an injector. In one embodiment, the heat dissipation element is a cylindrical element, or conductive plug, in contact with the injector valve body and the injector housing. In one embodiment, the heat dissipation element is a plurality of cooling fins, each being in direct contact with the injector housing. The fins may be used in combination with the cylindrical element to serve as an additional heat evacuation conduction path, allowing the heat to be dissipated by convection through the large surface area provided by the fins. The cylindrical element may be made of copper, but it is also within the scope of the invention that any suitable thermally conductive material may be used.

Abstract: The present application provides a mobile selective catalyst reduction system for use at a remote location. The mobile selective catalyst reduction system may include a first trailer with an ammonia delivery system and a tempering air system mounted thereon in whole or in part and a second trailer with a selective catalyst reduction section mounted thereon in whole or in part.

Abstract: Systems and methods related to an exhaust gas purification system comprising: an injector for injecting ammonia or a compound decomposable to ammonia into the exhaust gas, positioned downstream of an engine; a Cu-SCR catalyst positioned downstream of the injector, wherein no oxidation catalysts exist between the Cu-SCR catalyst and the engine; wherein the exhaust gas entering the Cu-SCR catalyst comprises an NH3/NOx ratio of less than 1.2.

Abstract: Methods and systems are provided for an exhaust gas mixer. In one example, a system may include a mixer configured to alter exhaust gas flow.

Abstract: This embodiment is a Stirling-Electric Hybrid automotive exhaust module generator device for converting waste heat energy into electrical energy by employing the Seebeck Effect. The disclosure herein describes how the invention converts heat energy, from hot exhaust gases, from the operation of an automotive external combustion engine (e. g. Stirling Cycle engine), into electrical energy which is fed back into the electrical system of the Stirling-Electric Hybrid Automobile (U.S. Pat. No. 7,726,130 B2) minimizing losses due to the second law of thermodynamics. The improvements on the art in this disclosure focuses on employing a plurality of thermopiles and materials with improved coefficients of thermal conductivity and increasing residence time of the hot exhaust gases by inducing turbulent flow through the module generator device in conjunction with external cooling plate(s), heat sink(s); in the form of a plurality of pin(s), on the interior and exterior surface(s) of the module generator device.

Abstract: A system includes one or more processors configured to be operably coupled to a vehicle system configured to travel along a route during a trip. The vehicle system has a vehicle particulate filter (VPF) disposed within an exhaust passage of the vehicle system. The one or more processors are configured to determine, based on trip information about the trip of the vehicle system, one or more regeneration-incompatible (RI) portions of the trip. The RI portions are associated with operating conditions of the vehicle system that are unsuitable for contemporaneous active regeneration of the VPF. The one or more processors are further configured to schedule an active regeneration (AR) event for the vehicle system based on the one or more RI portions of the trip. The AR event occurs during a regeneration portion of the trip.

Abstract: In accordance with at least one embodiment of an exhaust treatment system whereby parallel sections of exhaust filters such as Diesel particulate filters (DPF's) and a catalyst such as a selective catalytic reduction (SCR) system are integrated together while efficiently maintaining the temperature requirements of both. The parallel exhaust filter sections that may be heated and/or regenerated individually thereby facilitating catalyst temperature control and modulation of pressure drop across the exhaust filters.