Patent Application
20220381205
This disclosure relates generally to the field of vehicle exhaust systems, and more particularly to a valve assembly used in such exhaust systems.
A vehicle exhaust system includes various components to reduce emissions and control noise. In certain exhaust system applications, an Exhaust Gas Recirculation (EGR) system and/or an Exhaust Heat Recovery System (EHRS) are also utilized. The EGR is a system that allows the exhaust gases to be recirculated back into an engine intake manifold to reduce nitrogen oxides (NOx) emissions. In one example system, the exhaust gases are recirculated back into the engine intake manifold by using an external duct and an EGR valve. The EHRS captures thermal energy from the exhaust gas and transfers the thermal energy to another fluid such as engine coolant, for example. Providing a valve assembly to work with both systems presents challenges.
A vehicle exhaust component assembly, according to an exemplary aspect of the present disclosure includes, among other things, a valve housing having a first opening associated with a heat exchanger and a second opening associated with a bypass, and a valve body mounted for pivoting movement within the valve housing between at least a first position and a second position. The valve body has a first side and a second side opposite the first side. A first flap is mounted on the first side and is to be associated with the first opening. A second flap is mounted on the second side and is to be associated with the second opening.
In a further non-limiting embodiment of the foregoing vehicle exhaust component assembly, the first flap comprises a first spherical flap and the second flap comprises a second spherical flap.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the second spherical flap is connected to the first spherical flap via a shaft portion that extends through a body opening in the valve body, and the assembly includes a compliant member surrounding the shaft portion within the body opening and extending between the first spherical flap and the first side of the valve body and extending between the second spherical flap and the second side of the valve body.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the first flap comprises a conical flap and has an increasing outer dimension in a direction extending away from the first opening.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the second flap comprises a flat flap.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the flat flap has a ring shape that directly seals against a pipe planar end of the bypass when in the second position.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, a pivot shaft is mounted within the valve housing, and wherein the valve body comprises a vane that is fixed for pivoting movement with the pivot shaft, and including a second shaft that extends between the first flap and the vane.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the second shaft has a first end associated with the first flap and a second end associated with the vane, wherein the second end comprises a spherical ball portion that fits within a spherical recess in the vane to allow the second shaft to pivot relative to the vane.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, a compliant member is mounted around the second shaft adjacent to the spherical ball portion.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, a compliance housing encloses the compliant member between an inner surface of the compliance housing and the first side of the vane.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the compliant member comprises a wire mesh ring.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, an EGR system has an EGR pipe connected to an outlet from the heat exchanger and an EGR valve that is moveable between an open position to allow exhaust gas flow into the EGR pipe and a closed position to prevent exhaust gas flow in the EGR pipe.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, when the first flap seals the first opening and when the EGR valve is in the open position, exhaust gas flows through the heat exchanger to be cooled before entering the EGR pipe, and exhaust gas also flows through the bypass and into a downstream component; and when the first flap seals the first opening and when the EGR valve is in the closed position, exhaust gas only flows through the bypass.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, when the second flap seals the second opening and when the EGR valve is in the open position, exhaust gas flows through the heat exchanger to be cooled before entering the EGR pipe, exhaust gas is prevented from flowing through the bypass, and exhaust gas flows through the heat exchanger and is subsequently directed into the downstream component; and when the second flap seals the second opening and when the EGR valve is in the closed position, exhaust gas only flows through the heat exchanger and then into the downstream component, and exhaust gas is prevented from flowing through the bypass.
A vehicle exhaust component assembly, according to yet another exemplary aspect of the present disclosure includes, among other things, an EHRS including a heat exchanger having an exchanger inlet and an exchanger outlet, and an EGR system having an EGR pipe in communication with the heat exchanger outlet and an EGR valve moveable between an open position to allow exhaust gas flow into the EGR pipe and a closed position to prevent exhaust gas flow in the EGR pipe. A bypass tube is in parallel with the heat exchanger and has a bypass inlet that receives engine exhaust gases and which is in communication with the exchanger inlet, and a bypass outlet that directs the engine exhaust gases into a downstream component. A valve housing includes a first opening associated with the exchanger outlet, a second opening associated with the bypass outlet, and a third opening associated with an inlet to the downstream component. A valve body is mounted for pivoting movement within the valve housing, wherein the valve body has a first side and a second side opposite the first side, and wherein the valve body is moveable between at least a first position to close the first opening and a second position to close the second opening. A first flap is mounted on the first side to close the first opening and a second flap is mounted on the second side and is associated with the second opening.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the first flap comprises a conical flap and the second flap comprises a flat flap.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, a pivot shaft is mounted within the valve housing, and wherein the valve body comprises a vane that is fixed for pivoting movement with the pivot shaft, and including a second shaft that extends between the first flap and the vane, wherein the second shaft has a first end associated with the first flap and a second end associated with the vane, wherein the second end comprises a spherical ball portion that fits within a spherical recess in the vane to allow the second shaft to pivot relative to the vane.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, a compliant member is mounted around the second shaft adjacent to the spherical ball portion and a compliance housing encloses the compliant member between an inner surface of the compliance housing and the first side of the vane.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, the first flap comprises a first spherical flap and the second flap comprises a second spherical flap, wherein the second spherical flap is connected to the first spherical flap via a shaft portion that extends through a body opening in the valve body, and including a compliant member surrounding the shaft portion within the body opening and extending between the first spherical flap and the first side of the valve body and extending between the second spherical flap and the second side of the valve body.
In a further non-limiting embodiment of any of the foregoing vehicle exhaust component assemblies, when the first flap seals the first opening and when the EGR valve is in the open position, exhaust gas flows through the heat exchanger to be cooled before entering the EGR pipe, and exhaust gas also flows through the bypass tube and into the downstream component; when the first flap seals the first opening and when the EGR valve is in the closed position, exhaust gas only flows through the bypass; when the second flap seals the second opening and when the EGR valve is in the open position, exhaust gas flows through the heat exchanger to be cooled before entering the EGR pipe, exhaust gas is prevented from flowing through the bypass tube, and exhaust gas flows through the heat exchanger and is subsequently directed into the downstream component; and when the second flap seals the second opening and when the EGR valve is in the closed position, exhaust gas only flows through the heat exchanger and then into the downstream component, and exhaust gas is prevented from flowing through the bypass tube.
The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows:
This disclosure details an exemplary valve assembly for a vehicle exhaust system that includes an EHRS and an EGR system.
In one example, the EHRS 18 includes a heat exchanger 30 that allows the exchange of heat between the exhaust gases, passing through the heat exchanger 30, and a heat transfer fluid, such as a coolant for example. The heat exchanger 30 is arranged in parallel with the bypass tube 20. An inlet tube 32 connects an inlet 34 to the heat exchanger 30 to an inlet opening 36 to the bypass tube 20 and to an opening in the upstream pipe 14. A valve housing 38 connects an outlet opening 40 from the bypass tube 20 to the downstream pipe 22. The valve housing 38 is also connected to an outlet tube 42 that is connected to an outlet 44 from the heat exchanger 30. As such, the valve housing 38 includes a first opening 46 associated with the outlet opening 40 from the bypass tube 20, a second opening 48 associated with an inlet 50 to the downstream pipe 22, and a third opening 52 associated with the outlet tube 42.
In one example, an EGR system 54 is connected to the outlet tube 42. Thus, the outlet tube 42 has a first opening 56 associated with the outlet 44 from the heat exchanger 30, a second opening 58 associated within an inlet 60 to the EGR system 54, and a third opening 62 associated with the third opening 52 of the valve housing 38. The EGR system 54 includes at least one duct, tube, or pipe 64 that connects the inlet 60 to the EGR system 54 to an inlet 66 to an intake manifold 68 for the engine 12.
A valve assembly 70 is installed within the valve housing 38 to control flow between the EHRS 18 and the bypass tube 20. An EGR valve 72 is installed within the EGR pipe 64 to control when the exhaust gases are to be recirculated back into the engine intake manifold 68. The EGR valve 72 is a separate valve from the valve assembly 70. When the EGR valve 72 is closed, exhaust gases are prevented from entering the EGR pipe 64 and when the EGR valve 72 is open, exhaust gases are allowed to enter the EGR pipe 64 to be recirculated back to the intake manifold 68.
The valve assembly 70 is mounted on a pivot shaft 74 that is installed within the valve housing 38. The valve assembly 70 pivots between at least a first position shown in
When in the valve assembly 70 is in the first position, and if the EGR valve 72 is open, exhaust gas can flow through the heat exchanger 30 to be cooled before entering the EGR pipe 64 to be recirculated to the intake manifold 68. The exhaust gas also continues to flow through the bypass tube 20 and into the downstream pipe 22. When in the valve assembly 70 is in the first position, and if the EGR valve 72 is closed, exhaust gas only flows through the bypass tube 20.
When in the valve assembly 70 is in the second position, and if the EGR valve 72 is open, exhaust gas can flow through the heat exchanger 30 to be cooled before entering the EGR pipe 64 to be recirculated to the intake manifold 68. Exhaust gas is prevented from flowing through the bypass tube 20. Exhaust gas can also flow through the heat exchanger 30 and enter the outlet tube 42 where it can then be redirected into the downstream pipe 22. When in the valve assembly 70 is in the second position, and if the EGR valve 72 is closed, exhaust gas only flows through the heat exchanger 30 and then the outlet tube 42 where it is then directed into the downstream pipe 22. Exhaust gas is prevented from flowing through the bypass tube 20.
A control system includes a controller 76 that controls the valve assembly 70 and the EGR valve 72. The controller 76 can be a dedicated common electronic control unit or can be an electronic control unit associated with a vehicle system control unit or sub-system control unit. Each valve may also have its own dedicated controller 76. The controller 76 can include a processor, memory, and one or more input and/or output (I/O) device interface(s) that are communicatively coupled via a local interface. The controller 76 may be a hardware device for executing software, particularly software stored in memory that opens and closes the valves 70, 72 to achieve desired operational conditions.
In one example, the valve assembly 70 also includes a valve shaft 88 that connects the first flap 84 to the vane body 78, a compliant member 90, and a compliance housing 92 for the compliant member 90. The valve shaft 88 has a first end 94 coupled to the first flap 84 and a second end 96 coupled to the vane body 78. In one example, the second end 96 comprises a spherical ball portion 98 that fits within a spherical recess 100 in the vane body 78 to allow the valve shaft 88 to pivot relative to the vane body 78 (
In one example shown in
In one example, the compliant member 90 is mounted around the valve shaft 88 adjacent to the spherical ball portion 98. In one example, the compliant member 90 comprises a ring-shaped member having a first side 105 and a second side 106 (
In one example, the compliance housing 92 encloses the compliant member 90 between an inner surface of the compliance housing 92 and the first side 80 of the vane body 78. This mounting arrangement holds the compliant member 90 in place and seats the compliant member 90 against the ledge 104 of the valve shaft 88. This allows the compliant member 90 to absorb and dampen vibrations as well as allowing the spherical ball portion 98 to pivot within a defined range of motion within the compliance housing 92.
In one example shown in
As shown in
In one example, a flat plate 122 is mounted to an inner surface 124 of the valve housing 78 as shown in
In one example shown in
In one example, the second flap 86 comprises a flat flap that is mounted to the second side 82 of the vane body 78 at the rounded portion. In one example, the flat flap 86 has a ring shape (
In another example shown in
In one example, the first flap 202 comprises a first spherical flap and the second flap 204 comprises a second spherical flap. The first and second spherical flaps 202, 204 comprise half spheres or hemispheres that face their respective openings 52, 40 such that when engaged with the openings 52, 40 there is line contact as indicated at 206. By using a half sphere to contact a round opening in a valve body, a single line of contact is created to provide a tight seal. Movement of the valve assembly 200 between the first and second positions to cover the associated openings is the same as that described above with regard to valve assembly 70.
In this example, the second spherical flap 204 is connected to the first spherical flap 202 by a shaft portion 208. The shaft portion 208 has a significantly smaller cross-section relative to the cross-sections of the spherical flaps 202, 204, which forms a narrow neck between the flaps and comprises a double-mushroom shape. The vane body 78 includes a body opening 210 through which the shaft portion 208 extends such that the first spherical flap 202 is on one side 80 of the vane body 78 and the second spherical flap 204 is on an opposite side 82 of the vane body 78.
In one example, a compliant member 212 is inserted between the vane body 78 and the flaps 202, 204. The compliant member 212 also extends through the opening 210 in the vane body 78 and surrounds the shaft portion 208 within the opening 210. In one example shown in
The subject disclosure provides for an EHRS 18 combined with an EGR system 54, where the valve assembly 70, 200 is configured to reduce any leakage back toward the heat exchanger 30 as much as possible. Low leakage is required in order to keep the exhaust gas temperature for the EGR recirculation below at least 160° C., which is an example temperature limit for the EGR valve 72 at the intake manifold 68. As such, in one example, the target for temperature of exhaust gases after the heat exchanger 30 of the EHRS 18 should be around 130° C. The valve assembly 70, 200 provides good sealing such that the leakage is as low as possible in order to keep the exhaust gas as cool as possible after the heat exchanger 30. In one example there is a target of 2.2 kg/h at 860° C., for 55 kg/h going through the heat exchanger 30.
In one example, the subject disclosure accomplishes this by providing the valve assembly 70, 200 with two separate flaps, with one flap on each side of the valve body. One flap is configured to close the bypass tube 20, while the other flap is configured for interaction with the EGR path and consequently provides the low leakage interface. The subject valve assembly 70, 200 is also easy to assemble and provides flexibility to adjust with tolerances.
Additionally, the subject disclosure provides for a valve housing 38, which in one example, is associated with two round openings: a first opening 40 embodied by a pipe planar end of the bypass tube 20 and a second opening 126 embodied by a cut out in a plate 122 or an opening in the housing itself. The vane body 78 is configured to close the two openings by being articulated between two different positions via the pivot lever shaft 74. The subject vane body provides two different closure elements and includes a compliant insert 90, 212 that allows for multi-rotational movement. The compliant insert 90, 212 accommodates possible misalignment between the lever shaft 74 and the two openings to be closed, as well as reducing the noise associated vibrations generated by operation of the valve assembly 70.
In one example, the flaps are made from metallic material, which can introduce an undesirable noise effect during closing of the associated flap against a pipe or housing opening. This metal to metal contact noise can be offset by employing an actuator strategy via the controller 76 that slows the movement of the vane down significantly just prior to contact to minimize the impact.
Although a specific component relationship is illustrated in the figures of this disclosure, the illustrations are not intended to limit this disclosure. In other words, the placement and orientation of the various components shown could vary within the scope of this disclosure. In addition, the various figures accompanying this disclosure are not necessarily to scale, and some features may be exaggerated or minimized to show certain details of a particular component.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.
