Patent Application
20090014674
The present invention relates to a control valve for a motor vehicle, more specifically, a bypass valve assembly to selectively direct a fluid medium flow.
Two-stage turbochargers are commonly known and are used in all kinds of engines. They consist of a high-pressure (HP) turbine, and a low-pressure (LP) turbine, with each turbine having its own compressor. The HP turbine is typically smaller than the LP turbine, and rotates at faster speeds. During normal operating conditions, when the engine runs at lower speeds, (such as at a stop light), the only turbine in use is the HP turbine. When the engine is running at lower speeds, it creates less exhaust gas energy. This lower amount of exhaust gas energy is not enough to power the larger, LP turbine, but it does provide enough energy to power the smaller, HP turbine. During operation, as the engine begins to increase speed, the HP turbine is operated by the lower energy exhaust gases, but after the engine reaches a certain speed, the HP turbine no longer provides enough boost pressure to have any effect on engine performance. When this occurs, the LP turbine begins to operate and generate the higher level of boost pressure that the HP turbine cannot generate. Increasing engine speed also increases the exhaust gas energy, which is necessary to operate the LP turbine.
One common problem with this type of method of turbocharging is a phenomenon called “turbo lag.” Turbo lag refers to the moment in operation where the HP turbine stops having an effect on engine performance, and the LP turbine begins to have an effect on engine performance. Typically, the method for directing the exhaust gas from one turbine to the next is controlled by a valve. When the HP turbine is operating at maximum boost pressure, and no longer increases engine power, the valve will open. At this moment in operation, there is still not enough exhaust gas energy to operate the LP turbine. As the engine speed keeps increasing with acceleration, the exhaust gas energy increases to begin to cause the LP turbine to have an effect on engine performance. The time frame from which the valve opens, to the point where the LP turbine beings to have an effect on engine power is the period where turbo lag occurs. During this period, the driver of the vehicle will experience a reduction in engine power, while the LP turbine begins to operate. This condition is considered undesirable, and several forms of prior art have been developed to provide a smooth transition from the HP turbine to the LP turbine, thereby providing a smoother power increase to the engine.
Another common problem with two-stage turbochargers occurs at higher engine speed, when the HP turbine is not cut off from the air flow of the exhaust gas. During this condition, sometimes called “overspeed,” the increased exhaust gas energy can cause the HP turbine to spin at speeds which may cause damage. Control valves of two-stage series turbocharger systems have been applied to modulate the amount of exhaust gas pressure flowing into the LP turbine. These valves typically have been used for closing off exhaust gas flow to the LP turbine thereby only allowing the exhaust gas to flow only to the HP turbine until the HP turbine is no longer effective, at which point the valve opens a pathway to allow air to flow to the LP turbine. This is beneficial in providing boost pressure at low engine speeds, but does not aid preventing overspeed of the HP turbine.
Accordingly, there exists a need for an improvement in transitioning from the HP turbine to the LP turbine in a two-stage turbocharger system, as well as an improvement in the prevention in overspeed in a HP turbine.
Due to both federal and state regulations, the emissions allowed to be released during operation of motorized vehicles today are limited. One way to control the emissions released by the vehicle is to include an air management arrangement including a bypass valve and an exhaust gas recirculation unit (EGR). Generally, EGR bypass valves are used to recirculate exhaust gas back to the intake manifold of the engine. During periods when the exhaust gas temperature and pressure is high, such as when the engine speed increases with acceleration, the bypass valve can direct the exhaust gas through one outlet port to the EGR cooler chamber. During periods of low exhaust temperature and pressure, the bypass valve can direct the exhaust gas through the bypass port bypassing the EGR cooler chamber and entering the remaining components of the exhaust system.
A common problem with bypass valves is that they do not provide a tight seal or barrier with the two outlet ports since the bypass valves do not articulate in response to all seal surface geometries which can change due to thermal expansion as well as build-up of oil, dirt, grim, and the like.
Accordingly, there exists a need for an improved exhaust bypass unit having a valve unit used to fully restrict exhaust gas flow from passing through the selected cooler port or the selected bypass port.
The present invention is directed to a bypass valve assembly having a valve housing with an inlet port, outlet port, and bypass port all formed within the valve housing. A valve member is operably connected to the valve housing and includes a first valve plate and second valve plate that face in substantially opposite directions from each other. The first valve plate articulates to form a tight barrier with the outlet port when the valve member is in a first position, and the second valve plate articulates to form a tight barrier with the bypass port when the valve member is in a second position.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
a) is a perspective view of the valve member portion, according to the alternative embodiment of the present invention;
b) is a perspective view of the valve member portion, according to an alternative embodiment of the present invention;
a) is a perspective view of the valve member illustrating a second valve plate contacting a first plane associated with a second seating surface, according to the present invention;
b) is a perspective view of the valve member illustrating the second valve plate articulating in response to a second plane associated with a second seating surface, according to the present invention.
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring to
The HP turbine 16 and the LP turbine 22 are connected by a valve assembly 34 having a valve 36, shown in
The operation of the present invention configured for a single-bank exhaust system as shown in
During the process where all of the exhaust gas is being directed toward the HP turbine, the LP compressor 24 is not activated because it is controlled by the LP turbine 22, which is also not activated. The LP turbine 22 is larger in size compared to the HP turbine 16, and the LP compressor 24 is larger than the HP compressor 18. Neither are activated during this process because at lower engine speeds the volume of exhaust gas flow is not high enough to activate the LP turbine 22, and the volume of fresh air flowing into the system is not high enough for LP compressor 24 to effectively compress it. Directing all of the exhaust gas flow into the smaller HP turbine 16 allows the HP compressor 18 to provide the necessary amount of compressed air to flow into the intake manifold of the engine, increasing engine power at low engine speeds.
As the engine speed increases and the vehicle accelerates, the smaller HP turbine 16 and HP compressor 18 become less and less effective. When the engine speed increases to a certain predetermined value, the vehicle's electronic control unit commands the actuator to open the valve 36, lifting the second valve plate 50 away from the second contact surface 52, allowing exhaust gas from the exhaust manifold 28 to flow through the second exhaust manifold outlet 40, through the exhaust gas inlet port 60, and then through the valve assembly 34. The exhaust gas then exits through the LP turbine outlet port 64 of the valve assembly 34 and flows into the LP turbine 22, the exhaust gas then flows into the remaining exhaust system components. As the LP turbine 22 is activated from the increased exhaust gas pressure, the LP compressor 24 will begin to compress air coming in from the intake line 30. The compressed air is then forced through the outlet port 26 and into the intake conduit 32, where it then flows through the HP compressor 18, through the outlet port 20, and into the intake manifold of the engine. During this portion of operation, the air coming into the HP compressor 18 has already been pressurized by the LP compressor 24.
As the engine speed continues to increase, the valve 36 continues to rotate further away from the exhaust gas inlet port 60, and moves closer to the HP turbine inlet port 62. When it becomes necessary to direct all of the exhaust gas to flow directly into the LP turbine 22, the valve 36 moves into a position where the first valve plate 46 comes in contact with the first contact surface 48. When the valve 36 is in this position, exhaust gas cannot flow from the HP turbine 16 into the valve assembly 34. All of the exhaust gas flows from the exhaust manifold 28, through the second exhaust manifold outlet 40, and into the valve assembly 34. The valve 36 can be controlled by an actuator, or some other device, connected to the rotatable connector 66, which rotates the lever 44, thereby rotating the valve 36.
When closing off the second exhaust manifold outlet 40 or the HP turbine outlet 42, the valve 36 provides a smooth transition from the exhaust gas flowing through the HP turbine 16 to the LP turbine 22, and can be moved to any position therebetween to direct the flow of exhaust gas as driving conditions mandate.
It should also be noted that another advantage of the present invention is the orientation of the valve assembly 34 in relation to the HP turbine 16 and the LP turbine 22. The valve 36 is located in a position where the flow of exhaust gas pushes on the valve 36 when the first valve plate 46 is pressed against the first contact surface 48 and when the second valve plate 50 is pressed against the second contact surface 52. This also occurs when the valve 36 is located in any position therebetween. Also, the hinge assembly 58 is located in a position between the HP turbine outlet 42, and the second exhaust manifold outlet 40. Locating the hinge assembly 58 in this position allows for a single valve to be used for directing exhaust gas flow to either the HP turbine 16 or the LP turbine 22. Also, the valve assembly 34 is not only used for directing exhaust gas flow to each of the turbines, but the valve assembly 34 can also stop the flow of exhaust gas into the HP turbine 16, preventing overspeed and damage. Additionally, locating the valve 36 in the aforementioned position allows for greater control of the exhaust gas flow than compared to, for example, if the valve 36 were positioned in front of the second exhaust manifold outlet 40 or in front of the HP turbine outlet 42.
The present invention can also be used with engines having two exhaust banks, such as with a “V-6” or “V-8” engine. This embodiment is shown in
Referring generally to
Referring generally to
In further regard to
The pin 112 can have one wider end that prevents the first or second valve plate 108, 110 from sliding off of the pin 112. To prevent the opposing first or second valve plate 108, 110 from sliding off of the pin 112, an optional washer 120 is followed by an end cap 122 disposed at the opposite end of the pin 112. It is understood that alternatively the first and second valve plates 108, 110 can be secured by eliminating the optional washer 120 and forming or machining an end cap 122 on at least one of the ends of the pin 112. It is further understood that the raised bosses 109, 111 can alternatively be a single piece formed on either the first or second valve plate 108, 110 and also integrally formed with the pin 112. See
It is understood that alternatively, as shown in
The slidable connection of the first and second valve plates 108, 110 allows the valve plates 108, 110 to slide relative to the pivot arm 116 so that a space or gap is selectively formed between the pivot arm 116 and the first valve plate 108, or space is created between the pivot arm 116 and the second valve plate 110. The space accommodates radial movement and articulation of the first and second valve plates 108, 110 such that the first valve plate 108 can move relative to any geometry of the first seating surface 98 of the outlet port 84, and the second valve plate 110 can move relative to any geometry of the second seating surface 100 of the bypass port 88, thereby allowing the first and second valve plate 108, 110 to selectively close off the fluid medium from passing through either the outlet port 84 or the bypass port 88 respectively. It is understood that the slidable connection also forms a radial gap or clearance between flange 113 and the pivot arm 116 and aperture 118. The slidable connection and rotatability of the first and second valve plates 108, 110 about the circumference of the pin 112 accommodates radial movement, axial movement, and multi-axis-angular movement to compensate for any radial, axial, and multi-axis-angular misalignment, relative to any seating geometry to selectively create a tight seal or barrier for restricting the flow of the fluid medium. Since a change in the geometry of the first or second seating surface 98, 100 can occur due to ware, thermal expansion, or build up of foreign matter, including oil, dirt, grim, and dust this articulation feature allows the first and second valve plate 108, 110 to move in response to any geometry. It is understood that the valve member 106 can also be pivoted to an intermediate position such that the fluid medium can be variably directed through the outlet port 84 and bypass port 88 simultaneously, with the percentage of fluid medium passing through each port being dependent on the position of the valve member 106. It is further understood that when the bosses 109, 111 are formed on the first and second valve plates 108, 110, the bosses 109, 111 slide with respect to the pivot arm 116.
a) and 13(b) show an example of the articulation of the second valve plate 110 in response to any geometry of the second seating surface 100. Referring to
Referring to
The first housing 80 can be operably connected to the second housing 82 by aligning a first flange 144 of the first housing 80 with a second flange 146 (shown in
In operation, when the engine operation is at a predetermined condition, the vehicle's electronic control unit can command the actuator 140, or some other device, to rotate the valve member 106 to a first position relative to the outlet port 84 or a second position relative to the bypass port 88. The actuator 140 controls the valve member 106 by commanding rotation of the lever assembly 134 and the shaft 128, which pivots the pivot arm 116. When it becomes necessary to direct all of the fluid medium through the bypass port 88, the valve member 106 is rotated into a position where the first valve plate 108 articulates in response to the first seating surface 98 of the outlet port 84, thereby restricting substantially all of the fluid medium from entering the outlet port 84 and allowing the fluid medium to flow through the bypass port 88. When it becomes necessary to direct all of the fluid medium through the outlet port 84, the valve member 106 rotates into a position where the second valve plate 110 articulates in response with the second seating surface 100 of the bypass port 88, thereby restricting substantially all of the fluid medium from entering the bypass port 88 and allowing the fluid medium to flow through the outlet port 84. It is further understood that the actuator 140 can control the valve member 106 to move to any position between the outlet port 84 and bypass port 88 to distribute the fluid medium therebetween. As illustrated in
In another embodiment, the method of assembling the bypass valve assembly 76 includes providing the first housing 80, the second housing 82, the valve member 106, the lever assembly 134, and the actuator 140. The first housing 80 comprises the outlet port 84 and a first flange 144 at least partly surrounding an opening that is not an opening associated with the outlet port 84. The second housing 82 has the inlet port 86, the bypass port 88, the passage 130, and the second flange 146 that at least partly surrounds an opening that is not an opening associated with the inlet port 86, bypass port 88, or passage 30. Assembling the valve member 106 includes at least partly inserting the raised bosses 109, 111 of the respective first and second valve plate 108, 110 into the pivot arm aperture portion 118. The pin 112 is then inserted through the second valve plate 110 aperture 114, the raised bosses 109, 111, and the first valve plate 108 aperture 114. The end cap 122 is then either operably connecting or formed on both ends of the pin 112. If the optional washer is used 120, the pin 112 is inserted through the washer 120 before operably connecting or forming the end cap 122 on the pin 112.
The valve member 106 is then inserted through the opening defined by the second flange 146 and placed inside the second housing 82 at a location that allows the valve member 106 to pivot between a first position and a second position such that the second valve plate 110 can align with the bypass port 88 and the first valve plate 108 can align with the outlet port 84. The shaft 128 is then inserted through the passage 130 disposed within the second housing 82 and into the cylindrical tube 132 of the pivot arm 116, and the other end of the shaft 128 is left outside of the second housing 82 for connecting to the lever assembly 134. If the optional bushing 142 is used, the bushing 142 is inserted in the passage 130 prior to inserting the shaft 128. One end of the lever 136 of the lever assembly 134 is operably connected to the shaft 128, and the other end of the lever 136 is operably connected to the lever pivot 138 and washer 137.
The first flange 144 of the first housing 80 is operably connected to the second flange 146 of the second housing 82 by a plurality of bolts 148 and the like such that the first flange 144 is aligned with the second flange 146. Alternatively, a gasket 150, which can be adapted to receive the plurality of bolts 148, can be placed between the first flange 144 and the second flange 146 before connecting the first housing 80 to the second housing 82. It is understood that the first housing 80 and second housing 82 can alternatively be welded together, glued together, and the like.
The actuator 140 is operably connected to the lever pivot 138 by a plurality of locking nuts 152, bolts, and the like. For added stability of the actuator 140, an attachment bracket 154 can be disposed on the actuator 140 and connected to the valve housing 78 by a plurality of actuator bolts 156.
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
This application is a continuation-in-part of U.S. Non-Provisional patent application Ser. No. 11/125,959 filed on May 10, 2005.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11125959 | May 2005 | US |
| Child | 12217596 | US |
