WO2007089737A1

WO2007089737A1 - Combination variable geometry compressor, throttle valve, and recirculation valve

Info

Publication number: WO2007089737A1
Application number: PCT/US2007/002463
Authority: WO
Inventors: Volker Joergl; Timm Kiener; Olaf Weber
Original assignee: Borgwarner Inc.
Priority date: 2006-01-27
Filing date: 2007-01-26
Publication date: 2007-08-09

Abstract

A variable air intake mechanism can include diffuser vanes (52) or other suitable structures. If diffuser vanes (52) are used then they are vanes that can be altered in order to control the air flow through the compressor housing (33) or the recirculation channel (44). Thus, depending on whether a high or low flow in the recirculation channel (44) is required, the position of the diffuser vanes can be changed accordingly. This will provide an increase in compressor efficiency. The diffuser vanes (52) can also provide a throttling function that will eliminate the need to have a throttle valve further down stream from the compressor (28). In another aspect the position of the diffuser vanes (52) can be used to control the flow of fluid through the recirculation channel (44). Thus a single mechanism can provide increased compressor efficiency, throttling and recirculation control, or combinations thereof.

Description

COMBINATION VARIABLE GEOMETRY COMPRESSOR, THROTTLE VALVE, AND RECIRCULATION VALVE

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No.

60/762,702, filed January 27, 2006. The disclosure of the above application is incorporated herein by reference.

FIELD OF THE INVENTION The present invention relates to an air system which has a recirculation channel in order to control the pressure ratio of an output side of a compressor and an input side of the compressor.

BACKGROUND OF THE INVENTION Air systems are used in vehicles in order to increase the efficiency of an engine and reduce the emissions of the vehicle by recirculating exhaust gas and compressing the intake air. Air systems use a turbocharger where the exhaust gas passes through a turbine which is connected to a compressor. Thus, the compressor compresses intake air which is directed towards the intake manifold of the engine. However, the pressure ratio between the output of the compressor and the input of the compressor can be at such a high ratio that the air system is working under unstable operating conditions. These unstable operating conditions can lead to low compressor efficiency, material failure, or high emissions among other things. Therefore, it would be desirable to develop an air system in which the pressure ratio of the output side of the compressor and the input side of the compressor can be controlled in order to avoid operation under high pressure ratio conditions. It would also be desirable to design the recirculation system to reduce the pressure ratio in a compact assembly in order to reduce the amount of weight and space occupied by the additional components of the air system.

SUMMARY OF THE INVENTION The present invention relates to an air device having a rotatable compressor contained in a housing having an inlet and an outlet. The housing also has a variable air intake mechanism within the housing for varying the flow of fluid from the inlet to the outlet. A recirculation channel is also contained within the housing for recirculating at least some of the fluid to an area proximate the inlet of the housing when said variable air intake mechanism is at a closed position.

The variable air intake mechanism can include diffuser vanes or other suitable structures. If diffuser vanes are used then they are vanes that can be altered in order to control the air flow through the compressor housing or the recirculation channel. Thus, depending on whether a high or low flow in the recirculation channel is required, the position of the diffuser vanes can be changed accordingly. This will provide an increase in compressor efficiency. The diffuser vanes can also provide a throttling function that will eliminate the need to have a throttle valve further down stream from the compressor. In another aspect the position of the diffuser vanes can be used to control the flow of fluid through the recirculation channel. Thus a single mechanism can provide increased compressor efficiency, throttling and recirculation control, or combinations thereof.

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. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

Figure 1 is a schematic view of an air system containing the air device; Figure 2 is a perspective view of an air device; and

Figure 3 is a plan view of the diffuser vanes in relation to the recirculation channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 Figure 1, a schematic diagram of an exhaust gas recirculation system using an air device is generally shown. The air system 10 includes an engine 12 which has an exhaust manifold 14. Connected to the exhaust manifold 14 is a turbine 16 with variable vanes and an exhaust gas recirculation (EGR) path 18, such that the exhaust gas from the exhaust manifold 14 can enter either the turbine 16 or the EGR path 18. The exhaust gas that enters the EGR path 18 first passes through an EGR cooler 20 in order to reduce the temperature of the exhaust gas, and then pass through an EGR valve 22. The EGR valve 22 is a high pressure EGR valve. Next, the exhaust gas is mixed with an exhaust gas and fresh air combination and enters the engine's 12 intake manifold 24.

The exhaust gas that does not pass through the EGR path 18 passes through a turbine 16, which is operably connected to a compressor 28. Thus, a turbocharger 30 contains the turbine 16 and the compressor 28, and the exhaust gas rotates the turbine 16 which then rotates the compressor 28. After the exhaust gas passes through the turbine 16, the exhaust gas can pass through a diesel particulate filter 32 (DPF) which removes soot from the exhaust gas. After the exhaust gas passes through the DPF 32, a portion of the exhaust gas will exit the air system 10 through the exhaust pipe 34, and a portion of the exhaust gas can pass through a low pressure EGR throttle valve 36 and into an EGR path 38. The EGR throttle valve 36 can have an EGR valve portion and a throttle valve portion that are part of a single unit, or they may be separate units. The amount of gas that passes through each EGR path 38 is controlled by the EGR throttle valve 36, such that when the EGR throttle valve 36 is open more gas will pass through the EGR path 38 and when the EGR throttle valve 36 is closed more gas will exit the air system 10 through the exhaust pipe 34. Furthermore, the EGR throttle valve can work in combination so that the EGR valve portion can be opened and the throttle valve portion can be closed to allow maximum flow through the EGR path 38. Likewise, the EGR valve portion can be closed and the throttle valve portion can be opened to allow maximum flow through the exhaust pipe 34. The exhaust gas that does pass through the EGR path 38 then passes through an EGR cooler 42 in order to reduce the temperature of the exhaust gas. After passing through the EGR cooler 42, the exhaust gas is mixed with fresh air and moves to an air device 33 that contains the compressor 28, where the pressure of the exhaust gas and fresh air is increased. Thus, the pressure of the air on the input side of the corn pressor 28 is lower than the pressure of the air on the output side of the compressor 28.

Referring now to all the Figures, the present invention provides an air device 33 that combines a throttle valve aspect 26, variable outlet vanes aspect 27, compressor 28, a recirculation channel 44 and a recirculation valve aspect 46 into a single housing 29. Within the single housing 29 there is a variable air intake mechanism in the form of diffuser vanes 52 that provide the throttle valve aspect 26, variable outlet vanes aspect 27, and the recirculation valve aspect 46. The scope of this invention is not limited to providing all three aspects in one application. It is possible for the air device to have just single aspect or any combination of the three aspects described herein. The air device 33 controls the flow and pressure of fluid that flows onto a charge air cooler 48 and the intake manifold 24. The air device 33 can also work with the EGR path 18 to increase the uptake of high pressure EGR from the EGR path 18 to the intake manifold 24.

The housing 29 has an inlet 58 for receiving fluid medium such as outside air from an air intake 61, recirculated exhaust gas from the EGR path 38 or a mixture of outside air and exhaust gas. The housing 29 also has an outlet 60 that is connected to a path that leads to the intake manifold 24. The compressor 28 is circumscribed by two or more diffuser vanes 52. The diffuser vanes 52 can rotate between a closed position, an open position and any angular position therebetween. While diffuser vanes 52 are described it is possible for a different type of mechanism to be used. For example a butterfly valve or other valve mechanism that would be sufficient to control the flow of fluid through the air device 33 can be used.

Using only high pressure exhaust gas through the EGR path 18 can require higher flow which can be achieved by throttling the mass flow that flows through the compressor 28 which is typically carried out using a throttle valve located upstream of the EGR portion 18. The throttle valve aspect 26 of the present invention provides this desired result. When the diffuser vanes 52 are closed past a certain angle they will cause throttling of the fluid medium past the vanes 52. The angle that the throttling effect occurs will vary depending on several factors such as the shape of the blades on the compressor, the shape of the diffuser vanes, etc. This throttling action will lower the pressure downstream of the air device 33. This will cause increased flow from the EGR path 18. Thus, when the EGR valve 22 is open and the throttle valve aspect 26 is closed the maximum flow through the EGR path 18 is created. Likewise, when the EGR valve 22 is closed and the throttle valve aspect 26 is opened, the maximum amount of flow from the compressor 28 is entering the intake manifold 24.

When the diffuser vanes 52 move to an angle where they are more open and the throttling effect no longer occurs, the variable outlet vanes aspect 27 will be achieved. This occurs then the diffuser vanes are at or near a fully open position. The angle of the diffuser vanes 52 can be varied to increase the pressure produced by the air device 33. Varying the angle of flow past the vanes using the variable outlet vanes aspect 27 can cause the pressure to buildup by maximizing the flow path of fluid from the compressor wheel 28.

When the diffuser vanes 52 move to a closed position the throttle valve aspect 26 will occur and cause throttling of some of the fluid past the vanes. However, when the diffuser vanes 52 are closed there can be a buildup of back-pressure between the diffuser vanes 52 and the compressor wheel 28. This can cause damage to the compressor wheel 28. In order to stabilize the back-pressure, the recirculation valve aspect 46 is used. The recirculation valve aspect 46 includes using the diffuser vanes 52 to open and close a recirculation channel 44. The recirculation channel 44 is used to recirculate air from the output side of the compressor 28 to the input side of the compressor 28. The recirculation channel 44 can be formed within the housing 29 or it can be external. Recirculating the pressurized air through the recirculation channel 44 increases the internal mass flow through the compressor 28 without increasing the flow past the diffuser vanes 52. The flow through the recirculation channel 44 is controlled by a recirculation valve aspect 46 of the air device 33. Thus, when the recirculation valve aspect 46 is open the amount of air flow through the recirculation channel 44 is increased and when the recirculation valve aspect 46 is closed, the amount of air flow through the recirculation channel 44 is decreased. The recirculation valve 46 aspect and the recirculation channel 44 are inside the compressor housing 29 which compacts the size of the compressor 28, the recirculation channel 44, and the recirculation valve aspect 46. In an alternate embodiment, the recirculation channel 44 and a separate recirculation valve are outside the compressor housing 29 can be used.

The angle of the diffuser vanes 52 are controlled by an actuator which is designed to operate over the entire operating range of the diffuser vanes 52 and the recirculation channel 44, so long as the actuator has the necessary force to close the diffuser vanes 52 against the forces of the air flow. In an alternate embodiment, the diffuser vanes 52 and the recirculation channel 44 are operated by separate actuators (not shown), but this embodiment requires an increase in material and space. In addition the diffuser vanes 52 can be forced balanced so that the diffuser vanes 52 are all calibrated within the same tolerances.

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.

Claims

1. An air device comprising: a rotatable compressor contained in a housing having an inlet and an outlet; a variable air intake mechanism within said housing for varying the flow of fluid from said inlet to said outlet, and a recirculation channel within said housing for recirculating at least some of said fluid to said rotatable compressor when said variable air intake mechanism is at a closed position.

2. The air device of claim 1 wherein said inlet is connected to an external air source.

3. The air device of claim 2 wherein said inlet is connected to an exhaust gas recirculation passage for receiving exhaust gas from exhaust stream of an engine.

4. The air device of claim 1 wherein said outlet is connected to a cooler.

5. The air device of claim 1 wherein said outlet is connected to an engine intake manifold.

6. The air device of claim 1 further comprising a compressor passage formed in an area between said variable air intake mechanism and said rotatable compressor, wherein at least a portion of fluid from said compressor passage can flow to said outlet when said variable air intake mechanism moves toward said open position.

7. The air device of claim 6 wherein variable air intake mechanism is shaped and moves angularly to cause said at least a portion of said fluid to be throttled to said outlet.

8. The air device of claim 1 wherein said variable air intake mechanism has two or more diffuser vanes that circumscribe said rotatable compressor and said vanes rotate between an open and closed position to control the flow of fluid medium flowing from through said outlet of said housing and a compressor passage is formed in an area between said two or more diffuser vanes and said rotatable compressor.

9. The air device of claim 8 wherein the rotation of two or more diffuser vanes to a substantially closed position opens flow to said recirculation passage to control a pressure ratio between a pressure of said fluid medium at said inlet and a pressure of said fluid medium at said compressor passage.

10. The air device of claim 8 wherein said two or more diffuser vanes provide a throttle valve aspect, a recirculation valve aspect and a variable outlet vanes aspect.

11. The air device of claim 1 wherein said variable air intake mechanism has a throttle valve aspect, a recirculation valve aspect and a variable outlet vanes aspect.

12. An air device comprising: a housing having an inlet and an outlet and an intake passage formed by said housing; a rotatable compressor operably connected to said intake passage and said inlet; and two or more diffuser vanes circumscribing said rotatable compressor wherein said two or more diffuser vanes are operable to move between an open and closed position and any position therebetween, wherein said two or more diffuser vanes have a throttle valve aspect, a recirculation valve aspect and a variable vane outlet aspect.

13. The air device of claim 12 wherein said throttle valve aspect is the rotation of the two or more vanes to an angular position capable of causing the throttling of fluid past said two or more vanes.

14. The air device of claim 12 further comprising a recirculation channel within said housing for recirculating said fluid from said two or more diffuser vanes to said inlet of said housing, wherein said recirculation valve aspect is the mechanical opening of said recirculation channel by said two or more diffuser vanes when said two or more diffuser vanes are at a substantially closed position.

15. The air device of claim 12 wherein said inlet of said housing is connected to an exhaust gas recirculation passage.

16. The air device of claim 12 wherein said outlet of said housing is connected to a cooler, wherein fluid exiting said housing is cooled prior to moving further downstream.

17. The air device of claim 12 wherein said outlet of said housing is connected to an engine intake manifold.

18. The air device of claim 12 wherein the variable vane outlet aspect includes varying the angle of the two or more diffuser vanes to increase the pressure of the fluid produced by air device.

19. A method of operating an air device having a single housing with an inlet and outlet and a compressor positioned between said inlet and outlet, a throttle valve aspect in said housing, said method comprising the steps of: rotating said compressor in said housing to draw fluid medium through said inlet of said housing; and operating said throttle valve aspect to throttle said fluid medium and increase the flow through said outlet of said housing.

20. The method of claim 19 wherein said throttle valve aspect is provided by two or more diffuser vanes circumscribing said compressor rotating to an angle wherein the flow of fluid past said two or more vanes becomes throttled.

21. The method of claim 19 further comprising a variable outlet vanes aspect wherein when said two or more diffuser vanes rotate toward said open position, said variable outlet vanes aspect will be provided to increase the compressor efficiency.

22. The method of claim 19 further comprising the steps of providing a recirculation channel in said housing and a recirculation valve aspect operably connected to said recirculation channel in said housing; operating said recirculation valve aspect to direct fluid medium to said recirculation channel; and recirculating said fluid medium from said recirculation valve aspect to said inlet of said housing through said recirculation channel.

23. The method of claim 22 wherein said recirculation valve aspect and said recirculation channel allow said compressor to rotate freely and equalize the pressure within said housing.

24. A method of operating an air device having a single housing with an inlet and outlet and a compressor positioned between said inlet and outlet, a throttle valve aspect in said housing, a variable outlet vanes aspect in said housing, a recirculation valve aspect in said housing and a recirculation channel in said housing, said method comprising the steps of: rotating said compressor in said housing to draw fluid medium through said inlet of said housing; operating said throttle valve aspect to throttle a portion of said fluid medium and increase the flow through said outlet of said housing; operating said recirculation valve aspect to direct a portion of said fluid medium to said recirculation channel; recirculating said fluid medium from said recirculation valve aspect to said inlet of said housing through said recirculation channel; stopping said throttling aspect and operating said variable outlet vanes aspect increase the compressor efficiency.

25. The method of claim 24 wherein said throttle valve aspect is provided by two or more diffuser vanes circumscribing said compressor rotating to an angle wherein the flow of fluid past said two or more vanes become throttled.

26. The method of claim 24 wherein said recirculation valve aspect and said recirculation channel allow said compressor to rotate freely and equalize the pressure within said housing.

27. The method of claim 24 wherein said throttle valve aspect, said recirculation valve aspect, and said variable outlet vanes aspect are provided by two or more diffuser vanes circumscribing said compressor wheel, wherein said two or more diffuser vanes rotate between a closed position, an open position and any position there between.

28. The method of claim 24 further comprising an opening of said recirculation channel adjacent said two or more diffuser vanes wherein when said two or more diffuser vanes are in said open position, said opening of said recirculation channel is closed and when said two or more diffuser vanes are in a substantially closed position, said opening of said recirculation channel is open and receives the flow of said fluid medium.

29. A method of operating an air device having a single housing with an inlet and outlet and a compressor positioned between said inlet and outlet, a variable outlet vanes aspect in said housing, a recirculation valve aspect in said housing and a recirculation channel in said housing, said method comprising the steps of: rotating said compressor in said housing to draw fluid medium through said inlet of said housing; operating said recirculation valve aspect to direct a portion of said fluid medium to said recirculation channel; recirculating said fluid medium from said recirculation valve aspect to said inlet of said housing through said recirculation channel; and operating said variable outlet vanes aspect increase the compressor efficiency.

30. The method of claim 29 wherein said recirculation valve aspect and said recirculation channel allow said compressor to rotate freely and equalize the pressure within said housing.

31. The method of claim 29 wherein said recirculation valve aspect, and said variable outlet vanes aspect are provided by two or more diffuser vanes circumscribing said compressor wheel, wherein said two or more diffuser vanes rotate between a closed position, an open position and any position there between.

32. The method of claim 29 further comprising an opening of said recirculation channel adjacent said two or more diffuser vanes wherein when said two or more diffuser vanes are in said open position, said opening of said recirculation channel is closed and when said two or more diffuser vanes are in a substantially closed position, said opening of said recirculation channel is open and receives the flow of said fluid medium.