Valve assembly and method

Embodiments of the present disclosure present a valve assembly that includes a valve body having a gas passage bore, a valving bore extending along a longitudinal axis and intersecting the gas passage bore, a first bearing surface concentric with the longitudinal axis and a radially spaced apart second bearing surface concentric with the longitudinal axis, wherein an interface of the gas passage bore and the valving bore defines a flow port radially intermediate the first bearing surface and the second bearing surface. The valve assembly further includes a shaft valve extending along the longitudinal axis and rotatably mounted in the valving bore.

BACKGROUND

Field of the Disclosure

The present disclosure relates to valves and particularly to flow control including gas flow control and more particularly to butterfly type valves.

Description of Related Art

A valve is a device that is able to regulate or control the flow of a gas, liquid and/or particulates by opening and closing a channel or passageway. When a valve is in the open position, fluid is typically able to flow in a direction from high pressure to low pressure. When a valve is in the closed position, fluid flow is typically obstructed from flowing.

SUMMARY OF THE DISCLOSURE

In view of the foregoing, it is an object of the present disclosure to provide a method and apparatus.

A first exemplary embodiment of the present disclosure provides a valve assembly. The valve assembly includes a valve body having a gas passage bore, a valving bore extending along a longitudinal axis and intersecting the gas passage bore, a first annular bearing surface concentric with the longitudinal axis and a radially spaced apart second annular bearing surface concentric with the longitudinal axis, wherein an interface of the gas passage bore and the valving bore defines a flow port radially intermediate the first bearing surface and the second bearing surface. The valve assembly further includes a shaft valve extending along the longitudinal axis and rotatably mounted in the valving bore, the shaft valve having a first peripheral contact surface configured to engage the first bearing surface, a second peripheral contact surface configured to engage the second bearing surface and a vane radially intermediate the first peripheral contact surface and the second peripheral contact surface, wherein the first and the second peripheral contact surfaces have a given diameter and the vane encompasses the given diameter and wherein rotation of the shaft valve relative to the valve body selectively permits flow through the gas passage bore.

A second exemplary embodiment of the present disclosure provides an exhaust gas recirculation valve. The exhaust gas recirculation valve includes a valve body having a gas passage bore extending between at least one inlet and an at least one outlet, wherein the at least one inlet is configured to receive an exhaust gas from an exhaust manifold of an internal combustion engine and the at least one outlet is configured to pass exhaust to an inlet manifold of the internal combustion engine, the gas passage bore including a first inlet gas passage extending from the at least one inlet, the valve body having a valving bore intersecting the first inlet gas passage, the valving bore defining a first circular bearing surface and a second annular bearing surface. The exhaust gas recirculation valve further includes a shaft valve slideably received within the valving bore, the shaft valve having a first contact surface for rotatably engaging the first circular bearing surface and a second contact surface for rotatably engaging the second circular bearing surface, and a vane, wherein the first contact surface, the second contact surface and the vane have a common diameter.

A third exemplary embodiment of the present disclosure provides a method. The method includes providing a valve body having a gas passage bore, a valving bore extending along a longitudinal axis and intersecting the gas passage bore, a first annular bearing surface concentric with the longitudinal axis and a radially spaced apart second annular bearing surface concentric with the longitudinal axis, wherein an interface of the gas passage bore and the valving bore defines a flow port radially intermediate the first bearing surface and the second bearing surface. The method further includes providing a shaft valve extending along the longitudinal axis and rotatably mounted in the valving bore, the shaft valve having a first peripheral contact surface configured to engage the first bearing surface, a second peripheral contact surface configured to engage the second bearing surface and a vane radially intermediate the first peripheral contact surface and the second peripheral contact surface, wherein the first and the second peripheral contact surfaces have a given diameter and the vane encompasses the given diameter and wherein rotation of the shaft valve relative to the valve body selectively permits flow through the gas passage bore.

A fourth exemplary embodiment of the present disclosure provides a method. The method includes forming a valve body having a gas passage bore extending between at least one inlet and an at least one outlet, wherein the at least one inlet is configured to receive an exhaust gas from an exhaust manifold of an internal combustion engine and the at least one outlet is configured to pass exhaust to an inlet manifold of the internal combustion engine, the gas passage bore including a first inlet gas passage extending from the at least one inlet, the valve body having a valving bore intersecting the first inlet gas passage, the valving bore defining a first circular bearing surface and a second annular bearing surface. The method further includes forming a shaft valve slideably received within the valving bore, the shaft valve having a first contact surface for rotatably engaging the first circular bearing surface and a second contact surface for rotatably engaging the second circular bearing surface, and a vane, wherein the first contact surface, the second contact surface and the vane have a common diameter.

The following will describe embodiments of the present disclosure, but it should be appreciated that the present disclosure is not limited to the described embodiments and various modifications of the invention are possible without departing from the basic principles. The scope of the present disclosure is therefore to be determined solely by the appended claims.

DETAILED DESCRIPTION OF THE DISCLOSURE

Embodiments of the present disclosure can be used in exhaust gas recirculating valves (EGR) connected to exhaust manifolds101of a combustion engine103(shown inFIG.1) to divert metered amounts of the exhaust gas to intake manifolds105for re-burn by the engine. The exhaust gases are mixed with fresh air/fuel mixtures resulting in a lowering of combustion temperature and a reduction in the formation of harmful compounds such as nitrous oxide. Embodiments of the present disclosure provide a valve body and a single piece shaft valve having a vane with butterfly plate flow geometry. The diameter of the single piece shaft valve is relatively uniform throughout its longitudinal axis including the vane portion of the shaft valve.

It is contemplated that embodiments of the present disclosure can be used in place of traditional butterfly valves. In this embodiment, the valve will include a body having a relatively large-diameter first bore there through for passage of a gas, and a second relatively small-diameter bore transverse to the first bore for supporting a rotatable shaft on which is mounted a valve plate (known in the art as a “butterfly”) for controllably occluding the first bore in response to rotation of the shaft to control the flow of gas.

Embodiments of the valve of the present disclosure include a valve body and a shaft valve rotatably connected to the valve body.

Valve Body

Referring toFIGS.1and2, shown is a valve body102, which includes a gas passage bore104extending between an inlet and an outlet. It is contemplated in some configurations, the gas passage bore104will include a plurality of inlets or a plurality of outlets. As seen inFIG.2, the valve body102includes two gas inlet passages106,108and a combined gas outlet passage110. The two exhaust gas inlet passages106,108admit exhaust gases from an engine exhaust manifold101. The exhaust gas outlet passage110directs a metered flow of the exhaust gases toward an engine inlet manifold105.

The gas passage bore104can have any of a variety of cross sectional profiles (e.g., circular, oval, rectangular, triangular, etc), wherein the profile is constant or varies along a length of the bore.

The valve body102also includes a cylindrical valving bore112extending along a longitudinal axis and intersecting the gas passage bore104. As seen inFIG.2, the valving bore112extends through both inlet passages106,108of the gas passage bore104.

Each intersection of the valving bore112and the gas passage104defines a corresponding flow path cross sectional area.

Thus, the gas passage bore104can have a circular, obround, oval, rectilinear or faceted periphery, either at the intersection with the valving bore112, as well as upstream or downstream of the valving bore112.

A common or overlapping portion of the gas passage bore104and the valving bore112defines a sealing band114,116on opposite sides of the valving bore112, wherein the sealing bands114,116extend parallel to the longitudinal axis. As the valving bore112has a circular cross section, the sealing bands114,116have a generally arcuate cross section taken perpendicular to the longitudinal axis. Thus, the sealing bands114,116have a circumferential dimension about the longitudinal axis (shown inFIGS.7,10,11and14). The sealing bands114,116extend about the periphery of the valving bore112as well as extending parallel to the longitudinal axis. In the configuration having a plurality of inlet passages (shown inFIG.2), each intersection of the gas inlet passage106,108and the valving bore112includes a pair of opposing sealing bands114,116.

As set forth below, the sealing bands114,116can be defined by parallel edges118,120, each parallel to the longitudinal axis. Alternatively, the sealing bands114,116can include cut outs or a shaped edge122,124(shown inFIG.11) so that flow can be permitted or precluded (depending on the shaping) relative to an adjacent portion of the sealing band114,116. That is, the sealing band114,116can have varying circumferential dimension along the longitudinal axis. For example, one end of the sealing band114,116may have a circumferential dimension of 0.5 cm (or an arc of 3 degrees) and the other end of the sealing band may have a circumferential dimension of 0.25 cm (or an arc of 1.5 degrees). As set forth below, this shaping can provide for increased low flow control of the valve. Additionally, the curvature of sealing bands114,116provide a larger flow area than gas bore passage104allowing for increased flow over sealing bands114,116.

In conjunction with the shaping of the sealing band114,116, the valve body102can include fluting or channels126,128(shown inFIG.11) that extend from the sealing band114along the gas passage104. The valve body102can also include triangular or V-shaped channels1402,1404(shown inFIG.14). In these embodiments, the terminal edge of channels126,128or the terminal edge1406,1408of V-shaped channels1402,1404are adjacent to the sealing bands114,116and do not terminate at the same rotational location of the valve shaft140. Rather, the terminal edge1406,1408is also V-shaped such that it sealing bands114,116terminate at different rotational locations of the valve shaft140. A cross sectional top view of the valve body104atFIG.15illustrates the V-shaped channels1402,1404.

In another embodiment, the valve body102can have a substantially flat surface1502,1504adjacent the sealing bands114,116, and does not include channels126,128. This embodiment is shown inFIG.16, which depicts another cross sectional top view of valve body104.

The valving bore112also defines at least two or more bearing surfaces130,132(shown inFIG.2). As part of the valving bore112, the bearing surfaces130,132have the same diameter as the valving bore112. The bearing surfaces130,132are interfacing surfaces for supporting rotation of the shaft valve134relative to the valve body102. The bearing surfaces130,132are cylindrical in shape and have a diameter to provide for operable rotation of the shaft valve134relative to the valve body102.

Shaft Valve

The shaft valve134(shown inFIG.3andFIG.4) is a cylindrical member having a given diameter sized to be slideably received within the valving bore112and rotatably retained within the valving bore112.

The shaft valve134includes at least a first peripheral contact surface136configured to engage the first bearing surface130, a second peripheral contact surface138configured to engage the second bearing surface132. As seen in the figures, the shaft valve134can include a third, or additional, peripheral contact surfaces for rotatably engaging corresponding surfaces of the valve body102.

The peripheral contact surfaces136,138define a maximum diameter of the shaft valve134. Except for the vanes140,142, it is contemplated that other peripheral sections of the shaft valve134can have a slightly reduced diameter to facilitate operably locating the shaft valve134within the valving bore112and reduce rotating friction between the shaft valve134and the valve body102. However, excluding vanes140,142, it should be appreciated that embodiments of the shaft valve134include shaft valve134having a relatively uniform diameter throughout its longitudinal axis.

The sizing of the diameter of the shaft valve134to the valving bore112(and hence bearing surfaces130,132) is selected in accordance with standard engineering practices to permit the shaft valve134to be slid into the valving bore112and permit rotation of the shaft valve134relative to the valve body102. The diameter of the shaft valve134relative to the valving bore112is selected to permit rotation and accommodate tolerances of normal manufacturing processes. It should be appreciated that the shaft valve134is sized to valving bore112such that except for gas allowed to flow over the sealing surfaces and peripheral contact surfaces136,138when the shaft valve134is in the open position allowing gas to flow through gas passage bore104, gas is substantially obstructed from flowing between the shaft valve134and valving bore112.

As seen in the figures, the shaft valve134can include a length of reduced diameter to form a shank144for engaging a drive or control mechanism for selectively imparting rotation of the shaft valve134relative to the valve body102. The shank144can include a faceted portion or a flat or flats, keyways or splines, or any other shape to cooperatively engage with the drive or control mechanism. The drive or control mechanism can be any of a variety of configurations including an engine control module (ECM) and an electric, electromechanical or hydraulic motor.

The shaft valve134also includes a vane142longitudinally intermediate the first peripheral contact surface136and the second peripheral contact surface138. As seen in the figures, the shaft valve134can include a number of vanes140,142corresponding to the number of gas passage bores104.

The vanes140,142are configured to selectively engage the sealing bands114,116to preclude (maximally inhibit) flow through the respective gas passage114,116. That is, each edge of the vane140,142includes a seal face146,148, wherein the distance between the seal faces146, is the diameter of the shaft valve134.

The vanes140,142are generally defined by a pair of opposite recesses150,152in the shaft valve134. Thus, by rotation of the shaft valve134relative to the valve body102, the vane140moves from a sealed orientation with each seal faces146,148engaging a corresponding sealing band114,115of the valve body102to a fully open position parallel to the flow.

The sealing bands114,116can have any of a variety of configurations and dimensions. For example, by forming the sealing bands114,116to have a circumferential dimension that is greater, such as by 1.1, 1.4, 1.6 or more times a dimension of the seal face146,148of the vane140,142.

The recesses150,152forming the vane140can be configured to provide the vane140with a constant thickness across the diameter of the shaft valve134or a varying thickness across the shaft valve134. As seen inFIGS.7,10, and14, the vane140has a first thickness encompassing the longitudinal axis and a reduced or lesser thickness at the seal face146,148.

Referring toFIGS.7and10, the seal face146,148is defined by generally parallel edges extending parallel to the longitudinal axis. That is, the seal face146,148has a generally rectangular shape (though having a curvature corresponding to the cylindrical periphery of the shaft valve134) (shown inFIGS.8and9). However, as shown in the figures, it is possible to shape the seal face146,148so that the seal face146,148has a varied circumferential dimension wherein flow would be permitted along some of the vane140while remaining precluded from a different portion of the vane140as the vane140rotates relative to the valve body102.

Similarly, the sealing band114,115and corresponding seal face146,148can be differently sized for a given vane140. This further allows for customized flow control as for a predestined rotation of the shaft valve134, gas can flow about one edge of the vane140, while the remaining edge of the vane140precludes flow. Embodiments include the valve shaft134having a substantially flat sealing face146,148as shown inFIG.14. In the embodiment depicted inFIG.14, vane140includes steps1410, which allow for vane140to be formed through less costly manufacturing means. In this embodiment the shaft width (i.e., distance between sealing face146and sealing face148is slightly larger than the distance between sealing bands114,116in order to create a sealed interface between the sealing faces146,148and the sealing bands114,115to prevent a flow of gas through the passage when the shaft valve134is in the closed position.

By selecting the relative sizing of the sealing bands114,115of the valve body102and the seal face146,148of the vane140, the shaft valve134can permit slight rotation of the vane140relative the valve body102without permitting flow. That is, the sensitivity of the shaft valve134to a zero or null position relative to the valve body102can be reduced. Similarly, the sensitivity of the shaft valve134through low angle rotations relative to the valve body102can be reduced. As seen inFIG.11, approximately 5% of the flow can be controlled through approximately 50° of rotation. This is illustrated in the graph shown inFIG.12, which depicts the overall percentage flow rate on the y-axis versus rotational degree of the shaft valve134on the x-axis.

The sizing of the sealing band114,115and seal face146,148provide an overlapping interface that allows for the elimination of a conventional end stop point, as well as the elimination of valve shut off point shift due to thermal expansion dimensional changes at operating temperatures up to 720° C. Indeed, embodiments include the absence of a mechanical or physical stop or obstruction within or adjacent to the sealing bands114,115that prevent rotation of valve shaft134. In other words, embodiments include valve shaft134being operable to rotate in multiple directions and to multiple degrees greater than 360 degrees in either direction (e.g., clockwise or counterclockwise).

Referring to the figures, the shaft valve134can be used to set a maximum flow rate of the system. That is, by sizing the vane140to have a longitudinal dimension that is, for example 90%, 80% or 50% of the dimension of the gas passage bore104along the longitudinal axis, the shaft valve134can define a maximum flow path for the system. This allows the valve body102, and corresponding gas passage bore104to be sized to accommodate a relatively large system requiring a relatively high flow rate, wherein the longitudinal dimension of the vane140matches the longitudinal dimension of the associated gas passage bore104. However, since the shaft valve134can be readily replaced by merely sliding out a first shaft valve135having a vane141(shown inFIG.6) and sliding in a second shaft valve134, the second shaft valve134can have a vane140defined by a smaller longitudinal dimension, thereby restricting the maximum available flow rate of the valve. As shown inFIG.6, the longitudinal dimension of vane141is coextensive with the longitudinal dimension of gas passage bore104. Conversely, as shown inFIG.5, the longitudinal dimension of vane140is smaller than the longitudinal dimension of gas passage bore104. This allows a single size valve body102to be used in multiple operating environments.

As the shaft valve134can be used to limit the effective cross sectional area of the gas passage bore104, customization of the system is achieved by merely exchanging shaft valves134of different vane140configurations. As seen in the figures the longitudinal dimension of the vane140can be less than the longitudinal dimension of the gas passage bore104at the interface with the valving bore112. Thus, the shaft valve134effectively determines the available cross sectional flow area and hence flow rate.

It should be appreciated that while embodiments of the present valve assembly include a valve body102having two gas inlet passages106,108and a single gas outlet passage110(shown inFIG.2), embodiments of valve body102include a single gas inlet passage106and a single gas outlet passage110(shown inFIG.13). In this embodiment, shaft valve134includes a single vane140configured to selectively engage the sealing bands114,115to preclude flow through the gas passage104.

The presented embodiments offer significant advantages. These advantages include a reduced number of parts which lowers manufacturing costs as well as reduces the necessary steps for assembly. Further, as set forth above, as the shaft valve134can be replaced by merely sliding the old shaft valve134out of the valve body102and sliding the new shaft valve134into the valve body102, both component cost and assembly cost are reduced. Also, as the number of parts is reduced, the necessary accounting for accumulated tolerances is reduced, thereby increasing manufacturing pass rates.

The ability of the present system to confront an area of the sealing band114,115with an area of the seal face146,148, rather than line contacts of the prior designs, the present system can reduce leakage from approximately 30 Kg-40 Kg/hr to less than 10 Kg/hr and in select configurations less than 1 Kg/hr. This reduced leakage is believed to be necessary to meet more stringent emissions standards being adopted globally.

Because the contact surfaces of the shaft valve134have the same diameter as the vane140, the load on the bearing surfaces is less than in a traditional butterfly valve. In certain configurations, the bearing load is decreased by a factor of 4. As there is reduced bearing load, alternative (and cheaper) materials can be used for the valve body102as well as the shaft valve134. Thus, less exotic materials for the valve body102and shaft valve134are required.

The shaped sealing band114,115in conjunction with the channels126,128in the valve body102provides for the configuration of the port, such as the “V” shape shown inFIG.11, which improves a shearing action of accumulated combustion materials, such as soot and carbon. The improved shearing results from the seal face146,148of the vane140progressively coming into engagement with the sealing band114,115, rather than the entire seal face146,148engaging the entire sealing band114,115at one time. By progressively engaging, a lower torque control motor or drive can be used. The lower torque motor is less costly and typically adds less weight to the vehicle in which the present valve is installed. It should be appreciate that whileFIGS.11,14, and15depict “V” shaped channels126,128, embodiments of channels126,128can be shaped to include rectangular (shown inFIG.16), circular, oval (shown inFIG.9as sealing face146) or multiple “V” shaped channels in order to allow for different types of flow rate control through gas bore passage104.

As set forth above, the shaped sealing band and/or seal face which provide for the port configuration options such as “V” or other shapes change flow output versus angular rotation of the shaft valve134. This allows customization of the valve output flow for improved sensitivity at lower opening angles of the valve improving valve response. Additionally, the “V” shaped channels126,128not only allows for finer adjustments in the amount of flow through gas bore passage104, but channels126,128allow for finer adjustments in the velocity of flow through gas bore passage104. That is, rotation of valve shaft134allowing flow through only channels126,128will have a higher flow velocity when compared to the flow velocity when the sealing face146,148is no longer in contact with any portion of the sealing band114,115.

Also, the use of the shaft valve134provides flexibility to adjust maximum flow output by adjusting the machine depth or width of the recesses or cut outs in the shaft valve134as well as the number of cut outs without changing the package size or port configuration in the valve body102.

Reference is now made toFIG.17, which presents an exemplary method or process for providing embodiments of the present disclosure. The process begins at block1702, which states (a) providing valve body having a gas passage bore, a valving bore extending along a longitudinal axis and intersecting the gas passage bore, a first bearing surface concentric with the longitudinal axis and a radially spaced apart second bearing surface concentric with the longitudinal axis, wherein an interface of the gas passage bore and the valving bore defines a flow port radially intermediate the first bearing surface and the second bearing surface; and (b) providing a shaft valve extending along the longitudinal axis and rotatably mounted in the valving bore, the shaft valve having a first peripheral contact surface configured to engage the first bearing surface, a second peripheral contact surface configured to engage the second bearing surface and a vane radially intermediate the first peripheral contact surface and the second peripheral contact surface, wherein the first and the second peripheral contact surfaces have a given diameter and the vane encompasses the given diameter and wherein rotation of the shaft valve relative to the valve body selectively permits flow through the gas passage bore. Following block1702, block1704indicates wherein the valve body defines a pair of opposing sealing bands extending parallel to the longitudinal axis, each sealing band configured to engage a corresponding longitudinal edge of the vane.

Some of the other non-limiting embodiments include block1706, which specifies wherein the sealing bands have one of (i) a V-shaped edge adjacent a channel defined in the valve body operable to allow a flow to pass therethrough, (ii) a rectangular shaped edge, and (iii) an oval shaped edge. Next, block1708states wherein the first peripheral contact surface configured to engage the first bearing surface and the second peripheral contact surface configured to engage the second bearing surface are operable to contact accumulated combustion products disposed on an edge of the sealing bands. Block1710indicates wherein the first peripheral contact surface configured to engage the first bearing surface and wherein the shaft valve is operable to rotate unobstructed 360 degrees within the valving bore.