Patent Description:
An exhaust bypass valve is often used to control operation of serial turbocharger systems. Such a valve may be operated to physically divert exhaust or alter pressures in exhaust pathways, for example, to direct exhaust flow partially or fully to one of multiple turbines in a system. During operation, a typical exhaust bypass valve experiences high exhaust pressure on one side and lower pressure on the other side. To effectively seal the high pressure environment from the low pressure environment, considerable force is required to maintain contact between a valve and a valve seat. In a sealed state of a valve and valve seat, pressure differentials may challenge one or more inter-component seals and result in detrimental exhaust leakage. Patent publication <CIT> shows a serial turbocharger system with a seal mechanism for an exhaust bypass valve.

Aspects and preferred embodiments of the invention are defined in the appended claims.

A more complete understanding of the various methods, devices, assemblies, systems, arrangements, etc., described herein, and equivalents thereof, may be had by reference to the following detailed description when taken in conjunction with examples shown in the accompanying drawings where:.

Turbochargers are frequently utilized to increase output of an internal combustion engine. <FIG> shows a system <NUM> in two operational configurations (low engine RPM and high engine RPM) where the system <NUM> includes an internal combustion engine <NUM> and turbochargers <NUM>-<NUM> and <NUM>-<NUM> in a serial sequential arrangement.

The internal combustion engine <NUM> includes an engine block <NUM> housing one or more combustion chambers that operatively drive a shaft <NUM> (e.g., via pistons) where rotation of the shaft <NUM> determines, for example, engine revolutions per minute (RPM). As shown in <FIG>, an intake manifold <NUM> provides a flow path for air to the engine block <NUM> while an exhaust manifold <NUM> provides a flow path for exhaust from the engine block <NUM>.

Each of the turbochargers <NUM>-<NUM> and <NUM>-<NUM> can act to extract energy from the exhaust and to provide energy to intake air, which may be combined with fuel to form combustion gas. As shown in <FIG>, each of the turbochargers <NUM>-<NUM> and <NUM>-<NUM> includes a shaft <NUM>-<NUM> and <NUM>-<NUM>, a compressor <NUM>-<NUM> and <NUM>-<NUM>, and a turbine <NUM>-<NUM> and <NUM>-<NUM>. Each of the turbochargers <NUM>-<NUM> and <NUM>-<NUM> may include a housing, which may be referred to as a center housing (e.g., disposed between a respective compressor and turbine). As an example, a turbocharger shaft may be a shaft assembly that includes a variety of components.

As to fluid flow to and from the serial sequential arrangement of turbochargers <NUM>-<NUM> and <NUM>-<NUM>, an air intake <NUM> receives inlet air, which is directed to the compressor <NUM>-<NUM> and an exhaust outlet <NUM> receives exhaust from the turbine <NUM>-<NUM>, which may include an exhaust wastegate valve <NUM>. The wastegate valve <NUM> can be controlled to allow exhaust to bypass the turbine <NUM>-<NUM>. As an example, the turbine <NUM>-<NUM> may optionally include one or more variable geometry mechanisms such as, for example, vanes that can be adjusted to alter shape and/or size of exhaust throats that direct exhaust from a volute to blades of a turbine wheel (e.g., consider a variable nozzle turbine (VNT) or a variable geometry turbine (VGT)).

In the low engine RPM operational state, the turbochargers <NUM>-<NUM> and <NUM>-<NUM> are operated in series, sequentially. Specifically, exhaust from the exhaust manifold <NUM> is directed first to the turbine <NUM>-<NUM>, which causes rotation of the compressor <NUM>-<NUM>, and then to the turbine <NUM>-<NUM>, which causes rotation of the compressor <NUM>-<NUM>. As the turbine <NUM>-<NUM> extracts energy from the exhaust, the exhaust pressure decreases while the compressor <NUM>-<NUM> increases boost pressure (e.g., pressure differential between its inlet and outlet). In the example system <NUM>, based on compressor inlet pressure, the turbocharger <NUM>-<NUM> is referred to as a high pressure turbocharger while the turbocharger <NUM>-<NUM> is referred to as a low pressure turbocharger for the serial sequential operational state. As indicated in <FIG>, compressed intake air from the compressor <NUM>-<NUM> (e.g., receiving air at atmospheric conditions) is compressed and directed to an inlet of the compressor <NUM>-<NUM> (e.g., receiving the compressed air, which is at a pressure greater than atmospheric). Such an arrangement may be referred to as dual-stage compression.

In the low engine RPM operational state, an air valve <NUM> may be configured in an orientation that directs compressed air from the compressor <NUM>-<NUM> to the inlet of the compressor <NUM>-<NUM> and an exhaust valve <NUM> may be configured in an orientation that directs exhaust from the manifold <NUM> to the turbine <NUM>-<NUM>. During operation, either or both of the valves <NUM> and <NUM> may be regulated. For example, the valve <NUM> may be regulated such that at least some intake air bypasses the compressor <NUM>-<NUM> and the valve <NUM> may be regulated such that at least some exhaust bypasses the turbine <NUM>-<NUM>. Such regulation may occur while the system <NUM> is maintained in a serial sequential operational state. In contrast, when the air valve <NUM> is configured in an orientation that causes full or substantial bypass of the compressor <NUM>-<NUM> and when the exhaust valve is configured in an orientation that causes full or substantial bypass of the turbine <NUM>-<NUM>, the system <NUM> operates fully or essentially as a single turbocharger system. Such an operational state is typically selected for high engine RPM.

As the high engine RPM operational state relies on the turbocharger <NUM>-<NUM> and as high engine RPM logically follows low engine RPM, regulation of the exhaust valve <NUM> can act to pilot the low pressure turbocharger <NUM>-<NUM>. For example, when a preset engine RPM or boost pressure is reached, a controller may actuate the exhaust valve <NUM> to increase flow of exhaust to the turbine <NUM>-<NUM> (e.g., via physical diversion or pressure differential). In such a scenario, the increased flow to the turbine <NUM>-<NUM> increases rotational speed of the shaft <NUM>-<NUM>, which prepares the turbocharger <NUM>-<NUM> for a more rapid response and power output (e.g., with minimum turbo lag) upon configuration of the exhaust valve <NUM> in an orientation that causes full or significant bypass of the turbine <NUM>-<NUM>.

The system <NUM> may also include other features, for example, a heat exchanger (e.g., or heat exchangers) may be positioned to cool compressed intake air prior to delivery of the compressed air to the combustion chambers of the engine <NUM>. As an example, a heat exchanger may include a water-cooled compressor housing. As described herein, the system <NUM> may include one or more exhaust gas recirculation paths that can circulate exhaust to intake air; noting that exhaust valves and intake valves for combustion chambers of the engine <NUM> may be appropriately controlled to achieve some degree of exhaust "recirculation" (e.g., retention in a chamber).

In <FIG>, an example of a controller <NUM> is shown as including one or more processors <NUM>, memory <NUM> and one or more interfaces <NUM>. Such a controller may include circuitry such as circuitry of an engine control unit. Such a controller may include circuitry that provides for reading, writing or reading and writing information (e.g., executable instructions, control instructions, data, etc.) to memory (e.g., a computer-readable storage medium). As described herein, various methods or techniques may optionally be implemented in conjunction with a controller, for example, through control logic. Control logic may depend on one or more engine operating conditions. For example, sensors may transmit information to the controller <NUM> via the one or more interfaces <NUM>. Control logic may rely on such information and, in turn, the controller <NUM> may output control signals to control engine operation. The controller <NUM> may be configured to control an air valve (see, e.g., the air valve <NUM>), an exhaust valve (see, e.g., the exhaust valve <NUM>), a variable geometry assembly, a wastegate (see, e.g., the wastegate <NUM>), an electric motor, or one or more other components associated with an engine, an exhaust turbine (or exhaust turbines), a turbocharger (or turbochargers), etc. With respect to valves, the controller <NUM> may be configured to act as an actuator or to transmit a signal to an actuator configured to actuate, for example, the air valve <NUM>, the exhaust valve <NUM>, the wastegate valve <NUM> (e.g., to close or open a wastegate), etc..

<FIG> and <FIG> show perspective views of a system <NUM> with two turbochargers <NUM>-<NUM> and <NUM>-<NUM> along with an air outlet <NUM>, an air valve <NUM>, an exhaust manifold <NUM>, an exhaust valve <NUM>, a wastegate <NUM>, an air intake <NUM>, an exhaust outlet <NUM>, an air valve actuator <NUM>, a wastegate actuator <NUM> and an exhaust valve actuator <NUM>. Open headed arrows indicate intended air flow directions while solid headed arrows indicate intended exhaust flow directions. Each of the turbochargers <NUM>-<NUM> and <NUM>-<NUM> includes a compressor <NUM>-<NUM> and <NUM>-<NUM> and a turbine <NUM>-<NUM> and <NUM>-<NUM>.

As described herein, a system capable of serial sequential turbocharger operation and single turbocharger operation may be arranged in any of a variety of manners. For example, an exhaust valve may be located in a variety of positions depending on number, shape and size of exhaust conduits. In general, an exhaust valve acts to cause flow of exhaust predominantly to a larger of the turbochargers, which is often referred to as a low pressure turbocharger in a serial sequential arrangement. As mentioned, an exhaust valve may act to physically bypass a smaller, high pressure turbocharger or it may act to alter pressure in pathways. As to the latter, with reference to the system <NUM>, the exhaust valve <NUM> may be located adjacent the exhaust manifold <NUM> such that upon opening of the valve <NUM>, exhaust flows along a lower pressure pathway to the larger turbine <NUM>-<NUM> of the low pressure turbocharger <NUM>-<NUM>. In such an arrangement, the exhaust valve <NUM> can regulate exhaust flow form a high pressure source (e.g., manifold) to a lower pressure pathway.

As described herein, exhaust valve regulation may occur such that an exhaust valve is closed, open or in any intermediate state. In general, an exhaust valve opens in a direction facilitated by a pressure differential and closes in a direction opposed to the pressure differential. Such a valve arrangement provides for easier opening (e.g., less actuator force to open). An exhaust valve should be capable of effectively closing an exhaust opening (e.g., overcoming pressure differentials) such that, for low engine RPM, exhaust is directed to the smaller turbine.

<FIG> shows an example of an exhaust valve assembly <NUM> that may receive exhaust, for example, from a manifold and from an outlet of a turbine of a high pressure turbocharger (see, e.g., <FIG>, <FIG> and <FIG>). For example, the assembly <NUM> includes a housing <NUM> with an exhaust inlet flange <NUM> configured to be operatively coupled to another component (e.g., or components) for receipt of exhaust. As shown in <FIG>, the housing <NUM> defines a chamber <NUM> configured for receipt of exhaust, in part, responsive to position of a poppet <NUM> (e.g., a valve or valve plug), which is attached to and movable by an arm <NUM>, where the arm <NUM> may be attached to or linked to an actuator (see, e.g., actuator assembly <NUM>). As shown, a poppet can act as a plug, for example, to plug or seal an opening (e.g., to plug or seal an opening to an exhaust manifold coupled to an internal combustion engine).

In the example of <FIG>, the assembly <NUM> includes a valve seat <NUM> disposed between the housing <NUM> and another component <NUM>, which may be a part of a manifold, attached to a manifold, etc. As shown, the valve seat <NUM> includes a base portion <NUM> and a wall portion <NUM> that extends axially away from the base portion <NUM> (e.g., as a pipe, cylindrical wall, etc.). Where the base portion <NUM> and the wall portion <NUM> include substantially circular cross-sections, the base portion <NUM> can include an outer diameter that exceeds an outer diameter of the wall portion <NUM>. An exhaust passage is defined by an inner surface of the valve seat <NUM>, which may be a substantially cylindrical surface.

In the example assembly <NUM> of <FIG>, the housing <NUM> includes a recess <NUM> that extends axially inwardly from a face <NUM> of the housing <NUM> (e.g., optionally including one or more shoulders, etc.) and that can receive the valve seat <NUM>. In the example assembly <NUM> of <FIG>, the valve seat <NUM> includes a surface <NUM> and a surface <NUM>, which is disposed at an angle, for example, defined relative to the surface <NUM>, a planar surface of the component <NUM>, the face <NUM> of the housing <NUM>, etc., upon which the poppet <NUM> may be seated when the poppet <NUM> is in a closed state. Such an angle (e.g., a swing angle) may reduce a rotational angle when moving the poppet <NUM> between an open state and a closed state. As an example, a valve seat may include a surface to seat a poppet where the surface is disposed in an assembly at an angle of about zero degrees. For example, consider the valve seat <NUM> as having the surface <NUM> being parallel to the surface <NUM>, which may result in a greater travel distance (e.g., angle of rotation) for the arm <NUM> to seat the poppet <NUM> against the surface <NUM>. In such an example, a lower surface of the poppet <NUM> may be about parallel to the interface between the housing <NUM> and the component <NUM> (e.g., and about parallel to a plane of a gasket or gaskets disposed between the housing <NUM> and the component <NUM>). As an example, an angle may be considered in a force diagram, for example, to consider force applied to a valve seat by a poppet and balance of that force (e.g., as to one or more components that are in directly or indirectly in contact with the valve seat).

<FIG> shows a perspective view of an assembly <NUM> that includes a housing <NUM>, a valve seat <NUM>, a gasket <NUM> and a gasket <NUM>. In the example of <FIG>, the housing <NUM> includes an exhaust inlet flange <NUM> configured for connection to another component for receipt of exhaust and a housing flange <NUM> for operatively coupling the housing <NUM> to, for example, a center housing of a turbocharger. As shown in the example of <FIG>, the housing flange <NUM> includes an opening for receipt of a turbine (e.g., a turbine wheel) where, for example, exhaust entering via the exhaust inlet flange <NUM> may flow to a volute defined by the housing <NUM> to be directed to the turbine (e.g., and then axially outwardly from the turbine to an exhaust outlet of the housing <NUM>).

In the example of <FIG>, the housing <NUM> includes a recess <NUM>, a face <NUM> and a recess <NUM> as well as an edge <NUM> that defines an opening for flow of exhaust (e.g., from an outlet of a high pressure turbine). In the example assembly <NUM> of <FIG>, the gasket <NUM> is seated on the valve seat <NUM>, which is received by the recess <NUM> of the housing <NUM>, and the gasket <NUM> is seated in the recess <NUM> of the housing <NUM>. As an example, the gasket <NUM> may include a V-shaped cross-section formed by a single piece or multiple pieces where the V-shaped cross-section is open about an inner perimeter and closed about an outer perimeter. As an example, a closed side of a V-shaped cross-section of the gasket <NUM> may be formed by a joint between two pieces such as an upper piece and a lower piece. As an example, the joint may be formed upon application of clamping force (e.g., by joining two components with the two pieces of the gasket therebetween) or, for example, the joint may be formed by welding or other process to join two pieces (e.g., in a manner where a seal is formed therebetween).

As an example, a two-stage turbine bypass valve (TBV) can include a valve plug that, in a closed state, is to be held with force sufficient to overcome exhaust gas manifold pressure at low power/low engine rpm operating points. The relatively high pressure differential across the valve equates to a relatively large, continuous actuator force to be applied to via a TBV control mechanism (e.g., TBV control actuator).

As an example, an electric actuator can be utilized; however, an electrical actuator may be less desirable as to high, continuous load operating conditions due to the resistive heating of actuator motor coils, which can limit available peak, continuous force. As to relatively large vacuum pneumatic actuators, these require a vacuum source (e.g., engine mounted vacuum pump) and tend to be more suitable for on-off type operation rather than fine-control actuation, which can be desirable during the <NUM>-stage system transition from a high pressure turbo to a low pressure turbo.

As an example, a rotary actuator can be utilized to transition a TBV plug between closed and open states using a four bar linkage where a rod assembly includes a spring feature, which may be integral and/or a spring assembly fit to a rod, rod ends, etc. As an example, once a valve plug is in a closed state against a valve seat, an actuator continues to rotate a shaft (e.g., a peg, pin, etc.), applying an increased sealing force to the valve plug and stretching the spring feature. In such an example, the actuator can rotate to a degree that is past a linkage dead-point until contact is made with an external hard-stop while the valve plug remains relatively stationary with respect to the valve seat. Such contact can correspond to a closed and locked state where, for example, the actuator does not require electrical power to maintain the valve plug in the closed and locked state. For example, in a closed and locked state, the valve plug can be held closed (forming a seal with respect to the valve seat) via a spring load.

As an example, a linkage assembly can include a compliant (e.g., spring-based) member that enables the linkage assembly to pass over a mechanism dead-point to a self-locking state (e.g., akin to a vice-grip wrench mechanism). In such an example, the mechanism may be held with the valve plug in a closed state without requiring an external actuator load. In such an example, an electric actuator may be utilized that, for example, includes a shaft that can be rotated and operatively coupled to the linkage assembly.

As an example, an electric actuator can be utilized as part of a kinematic mechanism with force multiplication near a dead-point where self-locking effects to reduce requirements as to a continuous actuator force.

As an example, a mechanism can include one or more rigid linkages, one or more pivots, and one or more spring elements. As an example, various tolerances may be specified, surface treatments applied, etc..

As an example, a linkage assembly can include one or more coil springs and/or one or more spring washers (e.g., Belleville washers, etc.).

<FIG> shows an example of a two-stage turbocharger system <NUM> that includes turbochargers <NUM> and <NUM> that can receive exhaust via a manifold <NUM> where an actuator <NUM> can control a bypass valve <NUM> where a linkage assembly <NUM> is utilized as part of a control mechanism that connects the actuator <NUM> and the bypass valve <NUM>.

As shown in the example of <FIG>, the linkage assembly <NUM> includes a valve end <NUM> and an actuator end <NUM> where a linkage <NUM> includes a peg <NUM> operatively coupled to or part of the linkage assembly <NUM> and where the linkage <NUM> includes an opening or peg <NUM> operatively coupled to the bypass valve <NUM>.

In the example of <FIG>, the linkage assembly <NUM> includes an extension <NUM> with a relatively straight, axial portion <NUM> and a connector <NUM>. As shown, the linkage assembly <NUM> includes a spring-biased linkage <NUM> that has an axial span from the connector <NUM> to the actuator end <NUM> of the linkage assembly <NUM>.

<FIG> also shows the actuator <NUM> as including a rotatable shaft <NUM> operatively coupled to a linkage <NUM> that is operatively coupled to the actuator end <NUM> of the linkage assembly <NUM>.

As mentioned, a four bar linkage approach can be utilized as part of a valve control mechanism. In such an example, a spring-biased linkage can be included such as, for example, the spring-biased linkage <NUM> of <FIG>.

<FIG> shows example states for an assembly that includes a valve plug <NUM>, a valve seat <NUM>, a rotatable shaft <NUM>, a linkage <NUM>, a linkage assembly <NUM> with an actuator end <NUM> and a valve end <NUM>, a spring-biased linkage <NUM>, and a linkage <NUM> that includes a linkage end <NUM> and a plug shaft end <NUM>. As shown in <FIG>, the example states include an open state, a closed state and a locked state, which is shown as a closed and locked state. In the closed and locked state, a hard-stop <NUM> is shown as a surface against which the linkage <NUM> may be biased against (e.g., a hard-stop surface). In the closed and locked state, an electric actuator may consume little energy (e.g., parasitic consumption or vampire consumption) as the assembly can be maintained in the closed and locked state via mechanics including spring-biasing.

As an example, a linkage assembly can include a spring-biased linkage where the linkage assembly includes a first link and a second link that are connected via the spring-biased linkage. For example, two rigid links (e.g., link assemblies) can be connected by a spring pack (e.g., or spring package). In such an example, a linkage assembly can include rigid links (e.g., link assemblies) where one or both of the rigid links can be a piston or pistons that can slide in a cylindrical housing (e.g., bore) where one or more spring elements bias the piston or pistons. In such an example, one of the rigid links can be fixed (e.g., to a spring pack housing or portion of a spring pack housing) and the other rigid link can be movable, such as being translatable along an axis of a linkage assembly, and spring-biased.

<FIG> show a spring-biased linkage <NUM> in a side view (<FIG>) and in a cross-sectional cutaway view along a line A-A (<FIG>). As shown, the spring-biased linkage <NUM> includes coupling <NUM> and <NUM> that are operatively coupled to a spring package <NUM> that includes one or more spring elements <NUM>.

In <FIG>, an equation F = kz is shown as being an approximate spring equation for the spring package <NUM> where the spring package <NUM> can provide for an amount of axial displacement □z along a z-axis. The axial displacement □z along the z-axis corresponds to an amount of displacement as to the coupling <NUM> with respect to the coupling <NUM>. As shown, the coupling <NUM> is fixed to the spring package <NUM>, as explained below, and the coupling <NUM> is axially translatable with respect to the spring package <NUM> and biased by the spring package <NUM> (e.g., one or more spring elements, etc. of the spring package <NUM>).

As shown, the spring package <NUM> includes a housing <NUM> with opposing end <NUM> and <NUM> and a chamber <NUM> as defined at least in part via the housing <NUM>. As an example, the chamber <NUM> can be substantially cylindrical in shape where the one or more spring elements <NUM> are substantially cylindrical in shape. As an example, the chamber <NUM> can be defined at least in part via a bore surface of the housing <NUM>, which may be a cylindrical bore surface.

As shown in <FIG>, a rod assembly <NUM> includes, between opposing end <NUM> and <NUM>, rod portions <NUM>, <NUM> and <NUM> as well as piston portion <NUM> that moves with the rod portion <NUM> while the rod portions <NUM> and <NUM> are fixed to the housing <NUM> (e.g., immovably fixed to the housing <NUM>).

As shown, the rod portion <NUM> is fixed to the housing <NUM> (e.g., via matching exterior threads of the rod portion <NUM> and interior threads of the housing <NUM> while the piston portion <NUM> can be in contact with the one or more spring elements <NUM> to apply force thereto or to receive force therefrom where the one or more spring elements <NUM> are set within the chamber <NUM> of the housing <NUM> and where the one or more spring elements <NUM> define an opening through which the piston portion <NUM> of the rod assembly <NUM> passes.

In the example of <FIG>, the one or more spring elements <NUM> are substantially aligned as an axial stack that form opposing end surfaces and an opening or bore that extends between the opposing end surfaces where one of the end surfaces is supported by a wall of the housing <NUM> that defines in part the chamber <NUM> and where the other of the end surfaces can be in contact with (e.g., directly or indirectly) the piston portion <NUM> of the rod or rod assembly <NUM>. For example, the piston portion <NUM> can include a cap portion (e.g., of a "T" shape) that may be a component that can be threaded into a threaded bore of the piston portion <NUM>. In such an example, the cap portion can include an annular surface that can be of a diameter approximately the same as a diameter of an upper element of the one or more spring elements <NUM> (e.g., noting that flat washers may be included in a stack of one or more spring elements). The spring package <NUM> may operate as a spring-biased piston assembly where a portion of the rod assembly <NUM> acts as a piston that is biased by the one or more spring elements <NUM> as seated in the housing <NUM> of the spring package <NUM>. In the example of <FIG>, the spring-biased linkage <NUM> may act as the linkage <NUM>, or a portion thereof, of the assembly <NUM> of <FIG>. As an example, spring package <NUM> of <FIG> may function as part of the spring-biased linkage <NUM> of the assembly <NUM> of <FIG>.

In <FIG>, various adjustment features are shown, including adjustment nuts <NUM>, <NUM> and <NUM>. These nuts can include threads and may be utilized in combination with matching threads on one or more portions of the rod or rod assembly <NUM>. As shown, the coupling <NUM> includes a bore <NUM> that receives the rod portion <NUM> where the nut <NUM> may be utilized to determine an appropriate length as to a coupling feature <NUM> (e.g., an opening, etc.) of the coupling <NUM>. As shown, the coupling <NUM> includes a bore <NUM> that receives the rod portion <NUM> where the nut <NUM> may be utilized to determine an appropriate length as to a coupling feature <NUM> (e.g., an opening, etc.) of the coupling <NUM>.

As an example, the nut <NUM> may be utilized as part of an adjustment mechanism to adjust a load applied by the one or more spring elements <NUM>. For example, the nut <NUM> may adjust an axial limit as to the piston portion <NUM> of the rod assembly <NUM> with respect to the axial displacement □z (e.g., an axial throw limit, etc.). In such an example, the load can be a preload that is set such that a load greater than the preload will cause the one or more spring element <NUM> to compress and shorten in axial length while opposing couplings <NUM> and <NUM> move in opposite directions along the z-axis to length the distance between the coupling feature <NUM> and the coupling feature <NUM>.

<FIG> show the spring package <NUM> in two states where one state (right) is a compressed state compared to another state that is limited in axial position by the nut <NUM>, which may be a loaded state. In the example of <FIG>, the one or more spring elements <NUM> include a plurality of stacked spring washers (e.g., cone washers or coned washers). For example, about <NUM> to about <NUM> spring washers may be utilized, optionally with one or more flat washers. As an example, a number of spring washers and arrangement of spring washers may be utilized to achieve a desired load and/or spring constant.

<FIG> shows a top view of the spring package <NUM> and <FIG> shows an example of the rod portion <NUM> that includes multiple pieces <NUM>' and <NUM>" that may be coupled together to form the rod portion <NUM>. For example, the piece <NUM>' can be a rod piece and the piece <NUM>" can be a cap piece where the pieces <NUM>' and <NUM>" are connectable via threads, bayonet, or another type of attachment mechanism.

In <FIG>, various dimensions are shown such as an outer diameter (OD) D0 of the housing <NUM> and a threaded inner diameter (ID) D1 of the housing <NUM> (e.g., a threaded bore) for coupling of the rod portion <NUM> via matching threads on an outer diameter of the rod portion <NUM>. As an example, the housing <NUM> may include threads at the outer diameter D0 where inner diameter threads of a coupling of a rod portion may be threaded thereto to connect a rod portion to the housing <NUM>. As shown in <FIG>, the rod portion <NUM> may be attached such that a threaded portion threads into the housing <NUM> and a cap portion (e.g., of a "T" shape) contacts the end <NUM> of the housing <NUM>. For example, the rod portion <NUM> can include an axial portion with a first diameter and an axial portion with a second larger diameter that can define a surface that can abut a surface of the housing <NUM> at the end <NUM>. Where a housing includes OD threads, a coupling that includes ID threads may include a surface that can abut a surface of the housing. As an example, a washer (e.g., a locking washer) may be utilized to help assure that a threaded coupling mechanism remains immovable during operation.

In <FIG>, the dimensions illustrated also include an ID D2 of the housing <NUM>, an OD D3 of the rod portion <NUM>, an ID D4 of the housing <NUM>, a threaded OD D5 of the rod portion <NUM> that mates with ID threads of the nut <NUM>, and an OD D6 of the rod portion <NUM>. As shown, the nut <NUM> can be adjusted with respect to the rod portion <NUM> to determine a load applied by the one or more spring elements <NUM> to the rod portion <NUM> (e.g., at its cap; see, e.g., top view of <FIG> and example of <FIG>). As shown in the compressed state (right), the nut <NUM> can translate axially away from the end <NUM> of the housing <NUM> during operation where an amount of force may be approximated by a spring equation such as F = kz (e.g., F = k□z) where k is a spring parameter (e.g., a spring constant) of the one or more spring elements <NUM>, which may be substantially linear for a relatively small range of axial translation during operation (e.g., less than about <NUM>).

As mentioned the loaded state (left) can have a load adjusted via the number and/or arrangement of spring elements <NUM> and the nut <NUM>. In such an example, the load may be a base load where loading greater than the base load causes compression of the one or more spring elements <NUM>.

As shown in <FIG>, the one or more spring elements <NUM> can include an opening or openings that allow the rod portion <NUM>, at the OD D3, to pass therethrough and the housing <NUM> can include a bore portion, at the ID D4, that allows the rod portion <NUM>, at the OD D3, to pass therethrough. As mentioned, a cap or cap portion of the rod portion <NUM> may optionally be an attachable portion, for example, as shown in <FIG>. In such an example, the cap or cap portion may be attached during assembly or, for example, prior to assembly of the rod portion <NUM> with respect to the housing <NUM>.

<FIG> show an example of a spring-biased linkage <NUM> in a side view (<FIG>) and in a cross-sectional cutaway view along a line A-A (<FIG>). As shown, the spring-biased linkage <NUM> includes coupling <NUM> and <NUM> that are operatively coupled to a spring package <NUM> that includes one or more spring elements <NUM>.

In <FIG>, an equation F = kz is shown as being an approximate spring equation for the spring package <NUM> where the spring package <NUM> can provide for a set amount of axial displacement □z along a z-axis. The axial displacement □z along the z-axis corresponds to an amount of displacement as to the coupling <NUM> with respect to the coupling <NUM>. As shown, the coupling <NUM> is fixed to a portion of the spring package <NUM>, as explained below, and the coupling <NUM> is axially translatable with respect to a portion of the spring package <NUM> and biased by the spring package <NUM>.

As shown, the spring package <NUM> includes housings <NUM>-<NUM> and <NUM>-<NUM> with opposing end <NUM> and <NUM> and chambers <NUM>-<NUM> and <NUM>-<NUM> as defined at least in part via the housings <NUM>-<NUM> and <NUM>-<NUM>. As shown, the housing <NUM>-<NUM> is nested with respect to the housing <NUM>-<NUM> such that a portion of the housing <NUM>-<NUM> can move into and out of the chamber <NUM>-<NUM> as defined by the housing <NUM>-<NUM>. As an example, the chambers <NUM>-<NUM> and <NUM>-<NUM> can be substantially cylindrical in shape where the one or more spring elements <NUM> are substantially cylindrical in shape.

As shown in the example of <FIG>, a rod assembly <NUM> includes opposing end <NUM> and <NUM> with rod portion <NUM> and piston portion <NUM>. As shown, a pin <NUM> is received in a cross-bore <NUM> of the rod portion <NUM> of the rod assembly <NUM>, which can provide for contact with the end <NUM> of the spring package <NUM> (e.g., for transfer of force to or from the housing <NUM>-<NUM> as biased by the one or more spring elements <NUM>.

As shown, the coupling <NUM> extends into the housing <NUM>-<NUM> and <NUM>-<NUM> where an interference fit (e.g., a press-fit, etc.) may be made with respect to the housing <NUM>-<NUM> such that the coupling <NUM> is axially fixed (e.g., immovably) with respect to the housing <NUM>-<NUM>. The piston portion <NUM> passes through a bore <NUM> of the coupling <NUM> and the coupling <NUM> includes axially elongated openings <NUM> through which the pin <NUM> extends. In such an example, the rod assembly <NUM> can axially translate with the pin <NUM> to compress the one or more spring elements <NUM> or to receive a biasing force from the one or more spring elements <NUM>. As an example, the aforementioned axial displacement □z may be determined, for example, by an axial length of the elongated openings <NUM>.

As shown, the piston portion <NUM> can be operatively coupled to the housing <NUM>-<NUM> (e.g., a first housing) via the pin <NUM> in the cross-bore <NUM> and the one or more spring elements <NUM> can be supported by the housing <NUM>-<NUM> (e.g., a second housing) such that force can be transmitted from the piston portion <NUM> to the one or more spring elements <NUM> and such that force can be transmitted from the one or more spring elements <NUM> to the piston portion <NUM>. In such an example, the housing <NUM>-<NUM> can move with respect to the housing <NUM>-<NUM> where spacing (e.g., clearance) between the housings <NUM>-<NUM> and <NUM>-<NUM> about the outer surface of the housing <NUM>-<NUM> and the inner surface of the housing <NUM>-<NUM> can be dimensioned to help to prevent debris from entering the spring package <NUM>.

As shown in <FIG>, the one or more spring elements <NUM> can apply force to or receive force from the rod or rod assembly <NUM> via the piston portion <NUM> where the one or more spring elements <NUM> are set within the chambers <NUM>-<NUM> and <NUM>-<NUM> of the housings <NUM>-<NUM> and <NUM>-<NUM> and where the one or more spring elements <NUM> define an opening through which the piston portion <NUM> of the rod assembly <NUM> passes (e.g., within the bore <NUM> of the coupling <NUM>).

In the example of <FIG>, the one or more spring elements <NUM> are substantially aligned as an axial stack that form opposing end surfaces and an opening or bore that extends between the opposing end surfaces where one of the end surfaces is supported by a wall of the housing <NUM>-<NUM> that defines in part the chamber <NUM>-<NUM> and where the other of the end surfaces can be in contact with (e.g., indirectly via a portion of the housing <NUM>-<NUM>) the piston portion <NUM> of the rod assembly <NUM> via the pin <NUM> being received in the cross-bore <NUM> (e.g., which may define the portion <NUM> from the portion <NUM>). The spring package <NUM> may operate as a spring-biased piston assembly where the rod assembly <NUM> acts as a piston that is biased by the one or more spring elements <NUM> as seated in the housings <NUM>-<NUM> and <NUM>-<NUM> (e.g., housing caps, etc.) of the spring package <NUM>. In the example of <FIG>, the spring-biased linkage <NUM> may act as the linkage <NUM>, or a portion thereof, of the assembly <NUM> of <FIG>.

In the example of <FIG>, various adjustment features are shown, including an adjustment nut <NUM>. The adjustment nut <NUM> can include threads and may be utilized in combination with matching threads on one or more portions of the rod assembly <NUM>. As shown, the coupling <NUM> includes a bore <NUM> that receives the piston portion <NUM> where the nut <NUM> may be utilized to determine an appropriate length as to a coupling feature <NUM> (e.g., an opening, etc.) of the coupling <NUM>. As shown, the coupling <NUM> includes the bore <NUM> that receives the rod portion <NUM> where the coupling <NUM> is set at an appropriate length as to the housing <NUM>-<NUM> (e.g., via interference fit, welding, threads, crimping, a locking pin, a locking washer, etc.).

<FIG> show the spring package <NUM> in two states where one state (right) is a compressed state compared to another state that is limited in axial position by the opening <NUM> in the coupling <NUM>, which may be a loaded state. In the example of <FIG>, the one or more spring elements <NUM> include a plurality of stacked spring washers (e.g., cone washers or coned washers). For example, about <NUM> to about <NUM> spring washers may be utilized, optionally with one or more flat washers. As an example, a number of spring washers and arrangement of spring washers may be utilized to achieve a desired load and/or spring constant.

In the example states of <FIG>, various dimensions may be described, for example, with respect to a cylindrical coordinate system r, □ and z. For example, diameters and axial lengths may be defined for the various pieces as well as, for example, azimuthal positions such as the pin <NUM> being in the cross-bore <NUM> of the rod <NUM> where the coupling <NUM> includes the opening <NUM> as an elongated opening (e.g., oval, oblong, etc.) that can allow for positioning of the pin <NUM> as well as for determining an amount of load where a lower portion of the coupling <NUM> is coupled to the housing <NUM>-<NUM> in an axially immovable manner (e.g., interference fit, welding, threaded engagement, etc.). As an example, one or more features of the housing <NUM>-<NUM> and the coupling <NUM> can be one or more adjustment mechanism features that allow for adjustment of a preload (e.g., setting of a preload).

As shown in the example states of <FIG>, the rod <NUM> and the pin <NUM> translate axially downwardly such that the housing <NUM>-<NUM> moves deeper into the housing <NUM>-<NUM> and such that the one or more spring elements <NUM> compress in a manner that may be described via a spring equation such as, for example, F = kz (e.g., or F = k□z). As shown, the rod portion <NUM> translates in a bore <NUM> of the coupling <NUM> where the coupling <NUM> is fixed to the housing <NUM>-<NUM> and where the rod portion <NUM> is fixed via the pin <NUM> being received in the cross-bore <NUM> where the rod <NUM> includes the portion <NUM> axially above the pin <NUM> (e.g., the cross-bore <NUM>) and the portion <NUM> below the pin <NUM> (e.g., the cross-bore <NUM>).

<FIG> shows a perspective view of the spring-biased linkage <NUM> including the spring package <NUM> where the pin <NUM> is received via the elongated openings <NUM> in the coupling <NUM> and received via the cross-bore <NUM> in the rod <NUM>.

As shown in <FIG>, <FIG>, the spring-biased linkage <NUM> can be loaded, for example, with a preload. Such a preload may be set via a positional relationship between the coupling <NUM> and the rod <NUM>. For example, the housing <NUM>-<NUM> can be fixed to the coupling <NUM> in a manner that positions the pin <NUM> with respect to respective top portions of the two elongated openings <NUM> (e.g., parallel to each other and axially extensive) where the one or more spring elements <NUM> can be in a compressed state.

In <FIG>, the portion of the spring-biased linkage <NUM> is shown where the pin <NUM> is in contact with top portions of the elongated openings <NUM> as well as in contact with the end <NUM> of the spring package <NUM>. As shown in the compressed state of <FIG>, the pin <NUM> is moved downwardly away from the top portions of the elongated openings <NUM>. Where a preload is set, a force greater than the preload may further compress the one or more spring elements <NUM>. For example, where a preload pushes the pin upward in <FIG>, a downward force that overcomes that preload can further compress the one or more spring elements <NUM> and move the pin <NUM> downward, which can lengthen the spring-biased linkage <NUM>.

<FIG> shows an example of a spring washer <NUM> (e.g., a cone washer or a coned washer or a spring element), an example of a flat washer <NUM> and examples of spring washer stacks <NUM>, <NUM> and <NUM> (e.g., spring element stacks). As an example, the spring washer <NUM> may be made of metal or an alloy (e.g., a metallic material). As an example, consider a carbon steel, a stainless steel or another type of material that can withstand operational temperatures and that can provide suitable material properties. As an example, the spring washer <NUM> can be a Belleville washer (e.g., a Belleville spring).

As shown, the spring washer <NUM> can be defined by an outer diameter (OD) and an inner diameter (ID) as well as by a thickness (t), a height (h) along an axis z (e.g., a central cone axis), which may be measured from a bottom surface to a bottom edge of the inner diameter (e.g., opening), and an overall height (Ho), as measured from a bottom to a top. As shown, the overall height (Ho) can be an uncompressed height where, upon loading, the height of the spring washer <NUM> can decrease to a height less than the overall height (Ho). As shown, a plurality of the spring washers <NUM> may be stacked to form one or more types of stacks, optionally including one or more flat washers such as the flat washer <NUM>. In such examples, a stack height, a throw (e.g., □z), and a spring parameter for the throw may be determined. For example, a throw may be an axial dimension less than about <NUM> where the spring parameter may be substantially constant over the throw (e.g., F = k□z).

As an example, a throw may be a maximum expected throw that can allow for transitioning from one state to another state. For example, <FIG> shows the open state, the closed state and the closed and locked state for an assembly. As an example, consider transitioning from the closed state to the closed and locked state where the spring-biased linkage <NUM> can allow the linkage assembly <NUM> to increase in its axial length between ends <NUM> and <NUM> (e.g., stretch) such that a maximum axial length is achieved during the transition from the closed state to the closed and locked state. In such an example, in the closed and locked state, the spring-biased linkage <NUM> can decrease in its axial length between ends <NUM> and <NUM> (e.g., contract) and apply a load that may help to maintain the linkage assembly <NUM> in the closed and locked state.

In the closed and locked state, the load applied by the spring-biased linkage <NUM> may be sufficient to allow for an actuator to be in a low power state (e.g., vampire power state) or, for example, an off power state. For example, the spring-biased linkage <NUM> can pull the end <NUM> against the surface <NUM> to maintain the valve plug <NUM> in a closed and locked state with respect to the valve seat <NUM>.

To transition from the closed and locked state to the closed state and, for example, to the open state, an actuator may apply an actuation force that causes the linkage assembly <NUM> to lengthen axially via the spring-biased linkage <NUM>. As an example, during transitions from the closed state to one or more open states, the spring-biased linkage <NUM> may be at a substantially fixed axial length. For example, axial length changes can be for transitions into and out of the closed and locked state (e.g., with respect to the closed state).

As an example, a spring-biased linkage may be referred to as a spring-biased locking linkage that allow an assembly to be placed into a locked state. As an example, the spring-biased linkage <NUM>, the spring-biased linkage <NUM> and/or the spring-biased linkage <NUM> may be spring-biased locking linkages.

As an example, where a change in demand occurs, an actuator may be actuated (e.g., via electrical power) to transition from a closed and locked state to another state, which may be, for example, a closed and unlocked state or an open state. For example, one or more types of changes in demand may be associated with driving conditions, traffic signals, grade, etc. As an example, an actuator may optionally open a valve according to a control scheme that may be based on one or more factors (e.g., demand, pressure, etc.).

As mentioned with respect to <FIG>, regulation of the exhaust valve <NUM> can act to pilot the low pressure turbocharger <NUM>-<NUM>. For example, when a preset engine RPM or boost pressure is reached, a controller may actuate the exhaust valve <NUM> (e.g., transition to an open state or more open state) to increase flow of exhaust to the turbine <NUM>-<NUM> (e.g., via physical diversion or pressure differential). In such a scenario, the increased flow to the turbine <NUM>-<NUM> increases rotational speed of the shaft <NUM>-<NUM>, which prepares the turbocharger <NUM>-<NUM> for a more rapid response and power output (e.g., with minimum turbo lag) upon configuration of the exhaust valve <NUM> in an orientation that causes full or significant bypass of the turbine <NUM>-<NUM>.

As an example, a biasing mechanism can include a plurality of stacked coned washers that may be referred to as spring washers. For example, a biasing mechanism can include a plurality of Belleville washers, which can be coned washers (e.g., annular pieces of material that are angled as may be a portion of a cone). As an example, a coned washer can provide spring characteristics and may provide a relatively high fatigue life and a relatively high load capacity with a relatively small amount of deflection (e.g., of the order of millimeters, which may be less than about <NUM> or less than about <NUM> or less than about <NUM>).

As an example, coned washers may be stacked to modify an effective spring constant and/or an amount of deflection. As an example, stacking in the same conical direction can add to an effective spring constant in parallel, for example, to create a stiffer joint (e.g., with the same deflection); whereas, stacking in alternating conical directions can effectively be akin to adding springs in series, resulting in a lower spring constant and greater deflection. As an example, a biasing element can include stacking in one direction or stacking in two directions, for example, to tailor spring behavior and deflection.

As an example, where n washers are stacked in parallel (facing the same direction), the deflection is equal to that of one washer, while the load is n times that of one washer. On the other hand, if n washers are stacked in series (facing in alternating directions), the deflection is equal to n times that of one washer, while the load is equal to that of one washer. As an example, consider the following equation: <MAT> where ni is the number of washers in the ith group, g is the number of groups and k is the spring constant of one washer and K is the total.

As an example, a <NUM>-Stage TBV (Turbine Bypass Valve) mechanism can act to have a valve held closed against exhaust gas manifold pressure, for example, at low power/low engine RPM operating points. Relatively high pressure differentials across such a valve can require a relatively large, continuous actuator force to be applied to the mechanism. Various electric actuators may not necessarily be suited to high, continuous load operating conditions (e.g., due to the resistive heating of the actuator motor coils which can limit available peak, continuous force. Large vacuum pneumatic actuators may be used for these applications but they require a vacuum source (e.g., an engine mounted vacuum pump) and are more suited to on-off type operation rather than fine-control actuation which is desirable during the <NUM>-stage system transition from the high pressure turbo to the low pressure turbo.

<FIG> shows example states that include an open state <NUM>, a closed state <NUM> and a dead-point state <NUM>, an example plot <NUM> as to behavior of a spring-biased linkage and also shows an example plot <NUM> that includes operational paths (e.g., path segments) and states that are illustrated with respect to crank angle and actuator torque.

The example dead-point state <NUM> is illustrated with a dimension □z, which indicates an amount by which the linkage is extended in length compared to, for example, the example open state <NUM> and the example closed state <NUM>; noting that an example hard-stop state can include a length that is less than for the example dead-point state <NUM>. As shown in <FIG>, the axial length of the linkage can increase in the closed state <NUM> where a valve plug is in contact with a valve seat of the exhaust bypass valve. In such a state, contact force between the valve plug and the valve seat can increase, which can increase sealing of the exhaust bypass valve, for example, with respect to an exhaust gas pressure differential where exhaust pressure is greater on a valve seat side than a valve plug side of the exhaust bypass valve.

As shown in the plot <NUM>, a spring-biased linkage can include a preload of value FP where application of force (e.g., load) F in excess of the preload value FP causes the spring-biased linkage to increase in its axial length. A particular length of the spring-biased linkage can be for a dead-point force (e.g., dead-point load), indicated by FDP, which is shown to correspond to an axial increase in length of □z, which, in the example of <FIG>, occurs after the closed state <NUM>. As an example, a relationship such as F = kz may be utilized to determine one or more parameters that can be associated with control of an exhaust bypass valve. As an example, a spring parameter, which may be substantially constant over a relatively small displacement, may be determined via an arrangement of one or more cone washers in a spring-biased linkage. As an example, a method can include sizing a spring-biased linkage with respect to an exhaust bypass valve and an actuator, which may be an electric actuator. In such an example, these components can be operatively coupled such that a dead-point exists for a closed state of the exhaust bypass valve with respect to a valve seat such that power consumption of the electric actuator can be reduced (e.g., optionally to zero) while the closed state is maintained via force applied, at least in part, by the spring-biased linkage.

As an example, a method can include setting a preload value for a spring-biased linkage. For example, consider setting the value FP as shown in the plot <NUM> by adjusting one or more components of a spring-biased linkage such as the nut <NUM> as shown in <FIG> or, for example, setting an axial relationship between the housing <NUM>-<NUM> and the coupling <NUM> as shown in <FIG>. Or, for example, sizing a pin such as the pin <NUM> (e.g., and its associated opening <NUM>) as shown in <FIG>. As an example, a spring-biased linkage can be adjustable to set a preload value where lengthening of the spring-biased linkage occurs for load values greater than that preload value.

As shown in the plot <NUM>, the actuator torque increases to a peak at the dead-point that corresponds to the example dead-point state <NUM> and can then decrease to approximately zero (e.g., or zero) at a hard-stop that corresponds to hard-stop state. In the example of <FIG>, the difference in opening and closing paths can be due at least in part to, for example, exhaust pressure as exhaust pressure may facilitate opening a bypass valve.

As shown in the plot <NUM>, once the bypass valve is closed against a valve seat, the actuator can continue to rotate its shaft (e.g., or peg) to apply an increased sealing force to the bypass valve where the force stretches the spring-biased linkage (see, e.g., □z in the dead-point state <NUM>). As the actuator shaft rotates to a degree sufficient to move past the dead-point state of the linkage, the linkage may transition to a hard-stop state. In the hard-stop state, the actuator may be powered down (e.g., placed in a reduced power state), which may be a no power state. In the hard-stop state, the bypass valve can be held closed and sealed by the load provided by the spring-biased linkage.

As shown in the example of <FIG>, as a shaft or peg of the actuator rotates counter-clockwise, the bypass valve transitions from the open state <NUM> to the closed state <NUM> where the bypass valve is in contact with the valve seat; thus, further movement does not occur for the bypass valve with respect to the valve seat. However, when the shaft or peg of the actuator rotates further counter-clockwise, the force exerted by the actuator causes the spring-biased linkage to lengthen by compression of one or more spring elements. As an example, a dead-point can be a center point. As an example, a dead-point can be reached via a rotational mechanism such as rotation of a shaft of an electric actuator where a linkage is attached to the shaft, which may rotate in a clockwise and may rotate in a counter-clockwise direction.

As an example, a shaft of an electric actuator can rotate while a valve plug remains substantially stationary and in contact with a valve seat (i.e., a closed state). In such an example, while the valve plug is in the closed state with respect to the valve seat, a spring-biased linkage operatively coupled to the electric actuator and operatively coupled to the valve plug can increase in its axial length as force is applied by the electric actuator through rotation of its shaft where the applied force exceeds a preload of the spring-biased linkage.

While various examples refer to an electric actuator that can include a rotary shaft (e.g., rotary drive), as an example, an electric actuator can provide for linear actuation movement where the electric actuator is operatively coupled to a linkage mechanism that includes an arrangement of components with some amount of rotary movement and where the linkage mechanism includes a dead-point associated with a closed state of a valve plug with respect to a valve seat and where, at the dead-point, power may be reduced to the linear electric actuator.

<FIG> shows an example of an assembly <NUM> as in the dead-point state <NUM> of <FIG>. In the example of <FIG>, an actuator <NUM> can control a bypass valve <NUM> where a linkage assembly <NUM> is utilized as part of a control mechanism that connects the actuator <NUM> and the bypass valve <NUM>. <FIG> also shows a plot <NUM> (see, e.g., the plot <NUM> of <FIG>).

As shown in the example of <FIG>, the linkage assembly <NUM> includes a valve end <NUM> and an actuator end <NUM> where a linkage <NUM> (e.g., a bar) includes a peg <NUM> operatively coupled to or part of the linkage assembly <NUM> and where the linkage <NUM> includes an opening or peg <NUM> operatively coupled to the bypass valve <NUM> (e.g., as a rotatable shaft of the bypass valve <NUM> or operatively coupled to a rotatable shaft of the bypass valve <NUM>).

<FIG> also shows the actuator <NUM> as including a rotatable shaft operatively coupled to a linkage <NUM> that is operatively coupled to the actuator end <NUM> of the linkage assembly <NUM>. For example, the actuator <NUM> can be an electric actuator that includes a stator and a rotor driven by electrical power to rotate the rotor, which may be a rotatable shaft.

In the example of <FIG>, the linkage <NUM> can rotate clockwise and counter-clockwise via rotation of a rotatable shaft of the actuator <NUM> and the actuator end <NUM> can include, for example, an opening or a peg that is operatively coupled to the linkage <NUM>. Such a coupling can allow for a peg to rotate in an opening and/or an opening to rotate about a peg while the actuator end <NUM> can sweep an arc over a radius of the linkage <NUM>. As an example, a clip (e.g., a C-clip), a pin or other component may be included to secure the actuator end <NUM> with respect to the linkage <NUM>.

<FIG> shows the assembly <NUM> as including a valve plug <NUM>, a valve seat <NUM>, the peg <NUM> as a rotatable shaft that can rotate in a bore of a housing to cause the valve plug <NUM> to move toward the valve seat <NUM> and contact the valve seat <NUM> and to move away from the valve seat <NUM>. Example states of the bypass valve <NUM> can include an open state, a closed state and a locked state that is a closed and locked state. In the closed and locked state, the electric actuator <NUM> may consume little energy (e.g., parasitic consumption or vampire consumption) as the assembly can be maintained in the closed and locked state via mechanics including spring-biasing.

As an example, various components of the assembly <NUM> can be made of metal and/or an alloy (e.g., a metallic material). As an example, consider a carbon steel, a stainless steel or another type of material that can withstand operational temperatures and that can provide suitable material properties.

As an example, a load may be applied by a spring-biased linkage of a multibar linkage that maintains a bypass valve in a closed position which may correspond to a hard-stop state. As an example, an actuator may transition such a multibar linkage from the hard-stop state to a dead-point state (e.g., a center point state) via actuator torque applied via rotation of a shaft in a direction such that the bypass valve is in a closed position, which may be then transitioned to an open position via further rotation of the shaft in the same direction.

As an example, an assembly for an exhaust bypass valve of a two-stage turbocharger can include a first turbocharger stage; a second turbocharger stage; an exhaust bypass valve that includes an open state and a closed state; an actuator; and a linkage mechanism that links the exhaust bypass valve to the actuator where the linkage mechanism includes a spring-biased linkage with a preset load where, in the closed state of the exhaust bypass valve, an axial length of the spring-biased linkage increases responsive to application of a load by the actuator that exceeds the preset load. In such an example, the exhaust bypass valve can include a closed and locked state. In such an example, in an orientation between the closed state and the closed and locked state, the spring-biased linkage can be at a maximum axial length. As an example, in the closed and locked state the spring-biased linkage can apply a locking force.

As an example, a spring-biased linkage can include a housing and a rod fixed to the housing and a spring-biased rod translatable with respect to the housing. In such an example, the housing can define a chamber where at least one cone washer is disposed in the chamber.

As an example, a spring-biased linkage can include a first housing axially translatable with respect to a second housing, a rod fixed to the first housing and a rod fixed to the second housing. In such an example, the first housing and the second housing can define a chamber where at least one cone washer is disposed in the chamber.

As an example, an assembly for an exhaust bypass valve of a two-stage turbocharger can include a first turbocharger stage; a second turbocharger stage; an exhaust bypass valve that includes an open state and a closed state; an actuator; and a linkage mechanism that links the exhaust bypass valve to the actuator where the linkage mechanism includes a spring-biased linkage with a preset load where, in the closed state of the exhaust bypass valve, an axial length of the spring-biased linkage increases responsive to application of a load by the actuator that exceeds the preset load and where the assembly can include at least one cone washer, which may determine, at least in part, the preset load. For example, a cone washer can be loaded by applying force to the cone washer that compresses the cone washer in an axial direction to diminish a cone height. In such an example, the cone washer may be characterized at least in part by a spring constant (e.g., k) where an amount of force (e.g., load) can be defined via an equation that depends on the spring constant. As an example, for a relatively small distance of axial compression of a cone washer, behavior of the cone washer may be substantially linear where force may be represented as, for example, F = kz, where z is in an axial direction of the cone shape of the cone washer. For a single cone washer, a relatively small distance associated with axial compression may be of the order of millimeters (e.g., less than about <NUM>, less than about <NUM>, of the order of several millimeters, etc.).

As an example, an assembly can include a plurality of cone washers. In such an example, the assembly may include at least one flat washer disposed axially between two of a plurality of cone washers. As an example, an assembly can include a plurality of cone washers that include at least two cone washers in series.

As an example, an assembly can include a spring-biased linkage that includes a load adjustment mechanism for setting the spring-biased linkage to a preset load, for example, where the load adjustment mechanism sets an axial distance between opposing rods of the spring-biased linkage. Such an axial distance can be associated with a compression state of one or more spring elements of a spring package of the spring-biased linkage. In such a state, the one or more spring elements can exert a force axially outwardly such that, where a force greater than the preload force is applied, further compression of the one or more spring elements can occur along with axial lengthening of the spring-biased linkage.

As an example, a spring-biased linkage can include a rod and at least one cone washer that includes an opening where the rod is disposed in the opening.

As an example, a spring-biased linkage can include a spring-biased rod that is translatable with respect to an axially fixed rod.

As an example, an assembly can include an electric actuator. For example, consider an electric actuator that includes an electric motor that includes a shaft that is operatively coupled to a linkage mechanism that includes a spring-biased linkage, which may include one or more cone washers.

As an example, an assembly can include an exhaust bypass valve that, in an open state, allows at least a portion of exhaust gas of an internal combustion engine to bypass one of a plurality of turbocharger stages. As an example, consider a first turbocharger stage that is a low exhaust gas flow stage and a second turbocharger stage that is a high exhaust gas flow stage.

As an example, an assembly, in an open state of an exhaust bypass valve, can include a path that exists for at least a portion of exhaust gas of an internal combustion engine to bypass a first turbocharger stage.

As an example, a method can include actuating an electric motor operatively coupled to a linkage mechanism of an exhaust bypass valve of a two-stage turbocharger where the linkage mechanism includes a spring-biased linkage with a preset load where an axial length of the spring-biased linkage increases responsive to application of a load that exceeds the preset load; and transitioning the bypass valve from a closed to a closed and locked state by applying a load that exceeds the preset load to increase the axial length of the spring-biased linkage and then decreasing the load to decrease the axial length of the spring-biased linkage. In such a method, an axial length of the spring-biased linkage increases responsive to application of a load that exceeds the preset load where exhaust bypass valve is in the closed state where a valve plug contacts a valve seat. Such a method may be implemented in controlling an exhaust bypass valve of a multi-stage turbocharger system. As an example, such a method can include reducing power consumption of the electric motor, for example, by positioning the linkage mechanism in a particular state, which may be maintained at least in part via the spring-biased linkage (e.g., a dead-point state, which may be associated with a closed and locked state of the exhaust bypass valve).

As an example, an assembly for an exhaust bypass valve of a two-stage turbocharger can include a first turbocharger stage; a second turbocharger stage; an exhaust bypass valve that includes an open state and a closed state; and a linkage mechanism that links the exhaust bypass valve to an actuator where the linkage mechanism includes a locked state for the closed state of the exhaust bypass valve. In such an example, the linkage mechanism can include at least one spring.

As an example, a linkage mechanism can include a zero point that corresponds to a closed state of an exhaust bypass valve (e.g., exhaust gas bypass valve) where in transitioning to a locked state, the linkage mechanism increases in length and then decreases in length. In such an example, transitioning to an unlocked state can include increasing length followed by decreasing length.

As an example, an exhaust bypass valve, in an open state, can allow at least a portion of exhaust gas of an internal combustion engine to bypass one of multiple turbocharger stages. As an example, a first turbocharger stage can be a low exhaust gas flow stage and a second turbocharger stage can be a high exhaust gas flow stage. As an example, in the open state of an exhaust bypass valve, a path can be opened for at least a portion of exhaust gas of an internal combustion engine to bypass a first turbocharger stage.

As an example, a method can include transitioning a linkage mechanism via an actuator to a closed and locked state with respect to a valve and, while in the locked state, reducing power supplied to the actuator. For example, the actuator can be an electrically powered actuator where a reduction in power supplied thereto can allow the actuator to cool or, for example, not generate heat energy due to supply of electrical power. As an example, a duty cycle for a linkage mechanism and actuator system of a vehicle may be predominantly in a closed and locked state such that power supplied to the actuator can be for portions of the duty cycle where, for example, opening of a valve is desired (e.g., an exhaust bypass valve of a turbocharger system).

Claim 1:
An assembly for an exhaust bypass valve of a two-stage turbocharger (<NUM>), the assembly comprising:
a first turbocharger stage (<NUM>);
a second turbocharger stage (<NUM>);
an exhaust bypass valve (<NUM>) that comprises an open state, a closed state, and a closed and locked state;
an actuator (<NUM>); and
a linkage mechanism (<NUM>) that links the exhaust bypass valve to the actuator, wherein the linkage mechanism comprises a spring-biased linkage (<NUM>) with a preset load, the spring-biased linkage comprising a housing, a rod (<NUM>, <NUM>) fixed to the housing and an opposing spring-biased rod (<NUM>, <NUM>) translatable with respect to the housing, and a load adjustment mechanism for setting the spring-biased linkage to the preset load, wherein the load adjustment mechanism sets an axial distance between the rod and the opposing rod of the spring-biased linkage, and wherein:
(<NUM>) in the closed state of the exhaust bypass valve, an axial length of the spring-biased linkage increases responsive to application of a load by the actuator that exceeds the preset load;
(<NUM>) in an orientation between the closed state and the closed and locked state, the spring-biased linkage is at a maximum axial length; and
(<NUM>) in the closed and locked state, the spring-biased linkage applies a locking force.