WO2007098133A1

WO2007098133A1 - Turbocharger compressor housing with integrated throttle valve and recirculation-bypass system

Info

Publication number: WO2007098133A1
Application number: PCT/US2007/004322
Authority: WO
Inventors: Volker Joergl; Timm Kiener; Olaf Weber; Steven R. Mckinley
Original assignee: Borgwarner Inc.
Priority date: 2006-02-21
Filing date: 2007-02-21
Publication date: 2007-08-30

Abstract

A novel one or two stage turbocharged engine breather system achieves low nitrous oxide NOx emissions while having a high integration of components yet maintains cost competitiveness . A unique compressor breathing system for an engine integrates a throttle valve (26) , and a recirculation- bypass valve (46) having a recirculation feature that allows fluid to recirculate from an area proximate the compressor wheel (28) to an area near the system inlet. Additionally a bypass feature allows the passage to be used for bypassing high pressure fluid through the system without flowing past the compressor wheel.

Description

TURBOCHARGER COMPRESSOR HOUSING WITH INTEGRATED THROTTLE VALVE AND RECIRCULATION-BYPASS SYSTEM

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

60/775,050, filed February 21, 2006.

FIELD OF THE INVENTION

The present invention pertains to a turbocharger system for a single stage engine, more specifically, an engine breathing system having a compressor housing with an integrated throttle valve, and recirculation-bypass valve that can also be used as a bypass if used with a two stage turbocharged engine.

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-bypass 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

One aspect of the present invention includes a single stage turbocharged engine breathing system comprising an engine having an intake and exhaust manifold, an EGR valve and an EGR cooler that is positioned within an EGR path. This system further includes a turbocharger located at a position down stream of the EGR path with a filter adjacent the turbocharger for cleaning particulates. An exhaust throttle and EGR valve is located downstream of the filter along with an EGR cooler that is disposed between an exhaust pipe and an inlet pipe. A compressor is positioned inline with an air intake pipe and a recirculation-bypass channel bypasses gasses around the compressor and is controlled by a valve. A charge air cooler is positioned between the compressor and the intake manifold.

The system further includes a throttle valve that can be integral with the compressor housing, or a separate component. If the throttle valve is integral with the compressor housing, it may be linked to a separate recirculation- bypass mechanism for controlling air flow inside the housing.

Another aspect of the present invention includes a compressor for a turbocharged engine having a housing, a compressor wheel disposed within the housing and a throttle, and an internal bypass system consisting of an air recirculation-bypass channel, and a regulation mechanism. Through the use of a recirculation-bypass mechanism the pressure level of the high pressure area can be reduced during throttling.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

Fig. 1 is a schematic diagram of a one stage turbocharged diesel engine;

Fig. 2 is a schematic diagram of a two stage turbocharged diesel engine;

Fig. 3 is a side view of a compressor, schematically illustrating the integrated throttle valve in a partly closed position with the recirculation- bypass channel in an open position; and Fig. 4 is a side view, schematically illustrating a compressor showing an integrated throttle valve in its open position, while the recirculation-bypass channel is also in its open position.

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 Fig. 1, a schematic diagram of an exhaust gas recirculation-bypass system using an air device used in conjunction with a single stage turbocharger 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-bypass (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 - A -

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 compressor 28 is lower than the pressure of the air on the output side of the compressor 28. Referring now to Figs. 1 , 3 and 4, the present invention provides an air device 33 that combines a throttle valve aspect 26, a rotatable wheel or compressor 28, a recirculation-bypass channel 44 and a recirculation-bypass valve aspect 46 into a single housing 29.

Within the single housing 29 there is a variable air intake mechanism in the form of air device valve 52 that provides the throttle valve aspect 26, and the recirculation-bypass valve aspect 46. The scope of this invention is not limited to providing both aspects in one application but can include one or both of these aspects. 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 constituting a low pressure area for receiving fluid medium such as outside air from an air intake, 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 constituting a high pressure area that is connected to a path that leads to the intake manifold 24. The compressor 28 is circumscribed by the air device valve 52. The air device valve 52 can be a butterfly plate, drum, sliding collar or other type of valve. Figs. 3 and 4 depict the air device valve as a sliding collar connected to an actuator 62 or actuators. The actuator 62 can be any type of controlling mechanism, for example it can be a solenoid, pneumatic, hydraulic actuator or other type of system. The actuator 62 acts on the air device valve 52 to slide between a closed position, an open position and any position there between.

Using increased high pressure EGR flow through the EGR path 18 can be achieved through throttling while keeping the high pressure valve 22 fully open. The throttle valve aspect 26 of the present invention provides this desired result. As illustrated in Fig. 3, when the air device valve 52 is closed past a certain position throttling of the fluid medium past the air device valve 52 occurs. The throttling movement of the air past the air device valve 52 varies depending on several factors such as the shape air device valve, the degree of opening between the air device valve and the housing 29. 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.

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.

Fig. 4 illustrates the bypass aspect of the recirculation-bypass channel 44. When the air device valve 52 is in a more open position and the pressure at the inlet 58 of the air device 33 is greater than what the compressor 28 can move then the fluid moving through the air device 33 can bypass the compressor wheel 28 through the recirculation-bypass channel 44 and exit through the outlet 60. This type of situation would more likely occur in a system where there is another compressor or turbine passage located upstream of the air device 33 that would increase the pressure to the point where bypass would be beneficial. The flow of fluid through the recirculatioπ- bypass passage 44 is controlled by a regulation mechanism 53 that is operably connected to the air device valve 52. The regulation mechanism 53 can be a flange that slide in the recirculation-bypass passage 44 or it can be some type of valve member or mechanical device suitable for regulating flow. The regulation mechanism 53 must be designed to allow compressor bypass to occur when the air device valve 52 is at or near an open position, but cause recirculation to occur when the air device valve 52 is at or near a closed position. When the air device valve 52 slides to a closed position or a point near a closed position the throttle valve aspect 26 occurs, but there can be a buildup of back-pressure between the air device valve 52 and the compressor wheel 28. This is depicted in Fig. 3 of this application. This can cause damage to the compressor wheel 28. In order to stabilize the back-pressure, the recirculation-bypass valve aspect 46 is used. The recirculation-bypass valve aspect 46 includes using the air device valve 52 and regulating mechanism 53 to allow the fluid between the compressor 28 and the air device valve 52 to flow through the recirculation-bypass channel 44. This will recirculate air from the output side of the compressor 28 to the input side of the compressor 28. The recirculation-bypass channel 44 recirculates fluid back to the inlet 58 or an area proximate the inlet 58. The recirculation- bypass channel 44 can be formed within the housing 29 or it can be external. Recirculating the pressurized air through the recirculation-bypass channel 44 increases the internal mass flow through the compressor 28 without increasing the flow past the air device valve 52. The flow through the recirculation-bypass channel 44 is controlled by a recirculation-bypass valve aspect 46 of the air device 33. Thus, when the recirculation-bypass valve aspect 46 is open the amount of air flow through the recirculation-bypass channel 44 is increased and when the recirculation-bypass valve aspect 46 is closed, the amount of air flow through the recirculation-bypass channel 44 is decreased. The recirculation-bypass valve 46 aspect and the recirculation- bypass channel 44 are inside the compressor housing 29 which compacts the size of the compressor 28, the recirculation-bypass channel 44, and the recirculation-bypass valve aspect 46. In an alternate embodiment, the recirculation-bypass channel 44 and a separate recirculation-bypass valve are outside the compressor housing 29 can be used.

The position of the air device valve 52 is controlled by an actuator 62 which is designed to operate over the entire operating range of the air device valve 52 and the recirculation-bypass channel 44, so long as the actuator 62 has the necessary force to close the air device valve 52 against the forces of the air flow. In an alternate embodiment, the air device valve 52 and the recirculation-bypass channel 44 are operated by separate actuators (not shown), but this embodiment requires an increase in material and space. In addition the air device valve 52 can be forced balanced.

With reference now to Fig. 2, a two stage turbocharged diesel engine is illustrated depicting an alternate embodiment 110 of the present invention. The system 110 includes an engine 112 and exhaust gas manifold 116, and an intake manifold 114. A high pressure EGR path 146 delivers exhaust gas from exhaust manifold 116 to an intake path 140 that leads to an intake manifold 114 of the engine. A path 18 from the exhaust manifold 116 leads to a high pressure turbine 120 or a turbine bypass channel 160 or first channel with a bypass valve 162 for controlling the flow of fluid through the bypass channel 160. The bypass channel can be formed in part of the housing of the turbine 120 or it can be a separate channel. The bypass valve 162 and the bypass channel 160 function to selectively divert the flow of at least some and if necessary, all of the fluid around the turbine 120.

Fluid leaving the outlet of the first turbine 120 or bypass channel 160 is then introduced to a second turbine 164 or a second turbine bypass channel 166 with a bypass valve 168 that can divert some or all of the fluid around the second turbine 164. The second bypass channel 160 and bypass valve 168 can be formed in a housing that contains the second turbine 164 or it can be a separate component. Additionally it is possible for both the turbines 120, 164, bypass channels 160, 166 and bypass valves 162, 168 to be arranged in a single cast housing.

After fluid passes through the outlet of the second turbine 164 or second bypass channel 160, a filter 122 cleans soot from the existing fluid which is then delivered to an exhaust throttle and EGR valve system 124. The exhaust gas can go one of two ways, the first being to exit and be delivered to the exhaust pipe 126. Alternatively, the exhaust gas can be directed to an EGR path 142 which includes an EGR cooler 144. Gas to be recompressed can then be mixed with fresh air from inlet 128. Upstream from the inlet pipe 128 includes a low pressure compressor 170 and a high pressure compressor 28. A third air device 33 similar to the one depicted in Figs. 1, 3 and 4 is used and like reference numbers are used to designate similar or identical components. The recirculation-bypass channel 44 includes the air device valve 52 which is operable to bypass mixed gas around a rotatable wheel or compressor 28. A charge air cooler 136 cools the compressed gas prior to entry to an inlet 140 to the intake manifold 114.

It will be appreciated that the turbines 120 and 164 can be of a fixed geometry turbine or the variable geometry turbine configuration. It will also be appreciated that turbine bypass valves 162 and 168 can be eliminated, if so desired. It will also be appreciated that compressor 28 can be of smaller dimensions than compressor 170, if so desired. A brief description of the " operation of the two stage system 110 will now be presented. Thus the high mass flow from the compressor 170 can cause over speeding of the compressor 28. This can occur for various reasons, however, in a preferred embodiment the compressor 170 is larger than the compressor 28 which can cause over speeding. The bypass-recirculation channel 44 addresses this problem. In the event of a high mass flow through the compressor 170, the air device valve 52 is open, so that ail or a large amount of the decompressed air by the compressor 170 can bypass the compressor 28 through the bypass-recirculation channel 44 in order to avoid creating a high pressure drop through the compressor (i.e. running the compressor to the right of the choke line). Further, by opening air device valve 52 at very high mass flows can avoid over speeding of the compressor 28.

The flow of gas through the two stage system 110 is essentially the same as that discussed above concerning system 10, and will therefore, not be repeated herein. It will be appreciated that the low pressure compressor 170 can have an alternative compressor 200 which has an internal throttle valve and recirculation-bypass system. 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

CLAIMSWhat is claimed is:

1. An air device comprising: a housing having an inlet and an outlet formed by said housing; a compressor in said housing operably connected to said inlet; a channel formed in said housing; and a slid able collar in said housing circumscribing said compressor wherein said slidable collar is operable to move between an open and closed position and any position there between.

2. The air device of claim 1 wherein said slidable collar provides a throttle valve aspect and a recirculation-bypass valve aspect.

3. The air device of claim 2 wherein said throttle valve aspect is the movement of said slidable collar to a position capable of causing the throttling of fluid past said slidable collar.

4. The air device of claim 2 wherein said recirculation-bypass valve aspect is where the channel recirculates fluid from an area between said compressor and said sliding collar to an area proximate said inlet of said housing when said sliding collar is at a substantially closed position.

5. The air device of claim 1 wherein said channel is used to bypass the flow of fluid medium entering said inlet through said housing without coming into contact with said compressor when said sliding collar is in a substantially open position.

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

7. The air device of claim 1 , wherein fluid entering said inlet moves to a first path for directing air to the channel, or a second path for directing air to said compressor.

8. A two stage turbocharger system comprising: an engine having an intake and an exhaust manifold; a first turbine positioned downstream of said exhaust manifold, said first turbine having an inlet for receiving fluid from said exhaust manifold and outlet for moving said fluid downstream; a first channel that bypasses said first turbine, a second turbine positioned downstream of said first turbine, said second turbine having an inlet for receiving fluid from said first turbine and said first channel, said second turbine directs at least a portion of said fluid from said inlet to said outlet and into an exhaust path, a second channel that bypasses said second turbine; and an air device upstream of said intake of said engine, having a housing with an inlet and outlet, said outlet being operably connected to said intake, a high pressure compressor is operably contained within said housing and a recirculation-bypass channel and a recirculation-bypass valve bypassing the high pressure compressor.

9. The system of claim 8 further comprising a high pressure EGR path operably connected to said exhaust manifold and said intake.

10. The system of claim 8 further comprising a low pressure EGR path for moving fluid from said exhaust path to an area upstream of said air device.

11. The system of claim 10 further comprising a low pressure compressor operably connected to said low pressure EGR path and moving said fluid downstream to said air device.

12. The system of claim 8 further comprising a turbine bypass valve located in said first channel for controlling the flow of fluid through said first channel and a turbine bypass valve located in said second channel for controlling the flow of fluid through said second channel.

13. The system of claim 8 wherein said recirculation-bypass valve is a slidable collar in said housing circumscribing said high pressure compressor wherein said slidable collar is operable to move between an open and closed position and any position therebetween to control the flow of fluid through the outlet of said air device.

14. The system of claim 13 wherein said slidable collar further controls the flow of fluid through said channel when fluid bypasses the compressor through said recirculation-bypass channel.

15. The system of claim 13 wherein said recirculation-bypass channel is used to bypass the flow of fluid medium entering said inlet through said housing without coming into contact with said high pressure compressor when said sliding collar is in a substantially fully open position.

16. The system of claim 13 wherein said slidable collar provides a throttle valve aspect and a recirculation-bypass valve aspect.

17. The system of claim 16 wherein said throttle valve aspect is the movement of said slidable collar to a position capable of causing the throttling of fluid past said slidable collar.

18. The system of claim 16 wherein said recirculation-bypass valve aspect is where the recirculation-bypass channel recirculates fluid from an area between said high pressure compressor and said sliding collar to an area proximate said inlet of said housing when said sliding collar is at a substantially closed position.

19. A two stage turbocharger system comprising: an engine having an intake and an exhaust manifold, wherein said exhaust manifold emits fluid from said engine; a high pressure turbine downstream of said high pressure EGR exhaust manifold for receiving at least some of the fluid from said intake manifold; a low pressure turbine downstream of high pressure turbine, wherein said low pressure turbine directs fluid toward an exhaust path; a low pressure compressor operably connected to said low pressure EGR path and moving said fluid downstream toward said intake; and an air device downstream of said low pressure compressor and having a housing with an inlet and outlet, said outlet being operably connected to said intake, a high pressure compressor is operably contained within said housing and a recirculation-bypass channel and a recirculation-bypass valve bypassing the high pressure compressor.

20. The system of claim 19 wherein said recirculation-bypass valve is a slidable collar in said housing circumscribing said high pressure compressor wherein said slidable collar is operable to move between an open and closed position and any position therebetween to control the flow of fluid through the outlet of said air device.

21. The system of claim 20 wherein said slidable collar further controls the flow of fluid through said channel when fluid bypasses the compressor through said recirculation-bypass channel.

22. The system of claim 20 wherein said slidable collar provides a throttle valve aspect and a recirculation-bypass valve aspect.

23. The system of claim 20 wherein said recirculation-bypass aspect is used to bypass the flow of fluid medium entering said inlet through said housing without coming into contact with said high pressure compressor when said sliding collar is in a substantially fully open position.

24. The system of claim 20 wherein said throttle valve aspect is the movement of said slidable collar to a position capable of causing the throttling of fluid past said slidable collar.

25. The system of claim 20 wherein said recirculatiσn-bypass valve aspect is where the recirculation-bypass channel recirculates fluid from an area between said high pressure compressor and said sliding collar to an area proximate said intet of said housing when said sliding collar is at a substantially closed position.

26. The system of claim 19 further comprising a high pressure EGR path operably connected to said exhaust manifold and said intake.

27. The system of claim 19 further comprising a low pressure EGR path for moving fluid from said exhaust path to an area upstream of said air device.

28. The system of claim 19 further comprising a low pressure compressor operably connected to said low pressure EGR path and moving said fluid downstream to said air device.

29. The system of claim 19 further comprising a turbine bypass valve located in a first channel for controlling the flow of fluid through said first channel and a turbine bypass valve located in said second channel for controlling the flow of fluid through said second channel.