WO2014089035A1

WO2014089035A1 - Integrated supercharger and charge-air cooler system

Info

Publication number: WO2014089035A1
Application number: PCT/US2013/072803
Authority: WO
Inventors: Jon Paul TRUDEAU
Original assignee: Eaton Corporation
Priority date: 2012-12-03
Filing date: 2013-12-03
Publication date: 2014-06-12

Abstract

A supercharging system includes a positive displacement pump. The pump defines a rotor cavity configured to receive low-pressure inlet air and discharge high-pressure outlet air. Additionally, the pump includes first and second meshed rotors rotatably disposed in the cavity and configured to transform the low-pressure inlet air into the high-pressure outlet air. The supercharging system also includes a charge-air cooler configured to receive the outlet air from the pump and reduce temperature of the outlet air. The supercharging system additionally includes a housing configured to accommodate the pump and the charge-air cooler. The housing includes a backflow cavity configured to transfer the outlet air from the pump to the charge-air cooler. The backflow cavity includes a first curved surface leading in a first direction from the pump to the charge-air cooler and configured to streamline flow and minimize turbulence of the outlet air in the first direction.

Description

INTEGRATED SUPERCHARGER AND CHARGE- AIR COOLER SYSTEM

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is being filed on 03 December 2013, as a PCT

International Patent application and claims priority to U.S. Patent Application Serial No. 61/732,679 filed on 03 December 2012, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to an integrated positive displacement supercharger and charge-air cooler system.

BACKGROUND

[0003] It is known in the art to use positive displacement air pumps for supercharging internal combustion engines and for providing air for other purposes. Such a pump, when used as an automotive supercharger, can include a housing having a rotor cavity, an air inlet and an air outlet passage. In the cavity of the supercharger, a pair of meshed or interleaved rotors spin to pump air drawn through the inlet passage, and to subsequently discharge the air through the outlet passage.

[0004] Primarily due to the work imparted on the air by the supercharger, temperature of the discharged air is typically increased and its density drops. In order to reduce temperature and increase density of the air charge prior to introducing the discharged air into the engine, the air charge can be pumped through an air-to-air or air-to-liquid heat exchanger. Without the discharged air being passing through the heat exchanger prior to being introduced into the engine for combustion, the gain in engine's volumetric efficiency from supercharging can be significantly reduced.

SUMMARY

[0005] One aspect of the disclosure is directed to a supercharging system. The supercharging system includes a positive displacement pump. The pump defines a cavity configured to receive relatively low-pressure inlet air and discharge relatively high-pressure outlet air. Additionally, the pump includes first and second meshed rotors rotatably disposed in the cavity and configured to transform the relatively low-pressure inlet air into the relatively high-pressure outlet air. The supercharging system also includes a charge-air cooler configured to receive the outlet air from the pump and reduce temperature of the outlet air. Furthermore, the supercharging system includes a housing configured to accommodate the pump and the charge-air cooler. The housing defines a backflow cavity configured to receive the outlet air from the pump and convey the outlet air to the charge-air cooler. The backflow cavity includes a first curved surface leading in a first direction from the pump to the charge-air cooler and configured to streamline and manage flow and minimize turbulence of the outlet air in the first direction.

[0006] Another aspect of the disclosure is directed to an internal combustion engine having the supercharging system that includes the positive displacement pump and the charge-air cooler described above.

[0007] The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the many aspects of the present disclosure when taken in connection with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIGURE 1 is a side view of a supercharging system including a supercharger and charge-air cooler attached to an internal combustion engine.

[0009] FIGURE 2 is a sectional top view of the supercharging system depicted in Figure 1 , illustrating meshed rotors of the supercharger and the charge-air cooler banks.

[0010] FIGURE 3 is a perspective top view of the supercharging system depicted in Figure 1 with a housing cover removed to show a pressurized cavity.

[0011] FIGURE 4 is a perspective top view of supercharging system shown in Figure 3 with the housing cover installed.

[0012] FIGURE 5 is a bottom view of the housing cover showing a cover rib.

[0013] FIGURE 6 is a sectional perspective top view of supercharging system shown in Figure 4 illustrating a cavity rib in connection with the cover rib on the housing cover. DETAILED DESCRIPTION

[0014] Referring to the drawings wherein like reference numbers correspond to like or similar components throughout the several figures, Figure 1 illustrates an internal combustion (IC) engine 10 having a plurality of combustion chambers 12, and a crankshaft pulley 14. The crankshaft pulley 14 is driven by a crankshaft 15 of the engine 10. A supercharging system, generally indicated at 16, is shown attached to the engine 10. The supercharging system 16 is driven directly by the engine 10 via a belt 18. Accordingly, the supercharging system 16 can be used with the IC engine 10, and is operable to increase the volumetric efficiency thereof, as understood by those skilled in the art.

[0015] As shown in Figure 2, the supercharging system 16 includes a positive displacement pump or supercharger 20 and a charge-air cooler 22 integrated as a unit for convenient assembly onto the engine 10. Although the belt 18 is shown as the means of driving the supercharger 20, nothing precludes an auxiliary device, such as an electric motor (not shown), from being employed to drive the

supercharger. Additionally, while the subject supercharger 20 can be a roots-type supercharger having intermeshed lobed rotors, as shown in Figure 2, the

supercharger can also be a screw-type device having intermeshed lobed rotors or a centrifugal boosting device that makes use of centrifugal force in order to push additional air into an engine.

[0016] The supercharging system 16 is shown in detail in Figures 2 and 3. The supercharging system 16 includes an input drive 24 that can be rotatably driven by a positive torque from the belt 18, about an axis of rotation X at speeds proportional to speeds of the engine 10. The input drive 24 includes an input-shaft case 26. The input-shaft case 26 is typically formed from a light cast metal such as, for example, aluminum, magnesium, etc. The input-shaft case 26 includes a first end 28 and an opposed second end 30. The first end 28 can include an attachment provision for a housing 32 that is configured to enclose the supercharger 20 and the charge-air cooler 22. Similar to the input-shaft case 26, the housing 32 is typically formed from a cast metal, such as aluminum or magnesium. An input-shaft 34 having a first end 36 and a second end 38 can be arranged internal to the housing 32. The input- shaft 34 can be rotatably supported in the input-shaft case 26 by bearings 40 and 42. The housing 32, as well as many other aspects of the supercharging system 16, contains many ornamental aspects independent of functional aspects disclosed herein.

[0017] The first end 36 of the input-shaft 34 fixedly receives a pulley 44 that is connected to crankshaft pulley 14 via the belt 18, such that the supercharger 20 can be driven by the engine 10 (as shown in Figure 1). As shown in Figure 2, the second end 38 of the input-shaft 34 can include a flange 46 for engaging a coupler 48 that can in turn engage a first or driving timing gear 52 via studs 50. As additionally shown in Figure 2, the driving timing gear 52 can be continuously meshed with a second or driven timing gear 54. Hence, the input drive 24 directly can drive the first and second timing gears 52 and 54. The first timing gear 52 and the second timing gear 54 can be fixed relative to a first rotor shaft 56 and a second rotor shaft 58, respectively. As can be seen in Figure 2, each of the first and second rotor shafts 56, 58 can be rotatably mounted on bearings 59.

[0018] The rotor shafts 56 and 58 can be fixed to first and second interleaved and continuously meshed rotors 60 and 62, respectively, for unitary rotation therewith. The meshed timing gears 52 and 54 can therefore be fixed relative to the first and second rotors 60, 62, respectively, particularly in order to prevent contact between the rotors during operation of the supercharger 20. The first and second rotors 60, 62 can be mounted for synchronous rotation in a rotor cavity 64 formed in the housing 32. The housing 32 can include a low-pressure air inlet port 65 arranged to admit the typically ambient relatively low-pressure inlet air 66 to the first and second rotors 60, 62. The relatively low-pressure inlet air 66 can generally enter inlet port 65 via a throttle body assembly (not shown) which controls the amount of incoming air based on engine speed and load. As is known by those skilled in the art, the relatively low-pressure inlet air 66 is compressed by the first and second rotors 60, 62. Thus, the relatively low-pressure inlet air 66 is transformed by the first and second rotors 60, 62 into relatively high-pressure outlet air 68 (shown in Figure 3) as the air is accumulated in the inlet port 65 or other plenum areas.

[0019] As shown in Figure 3, the relatively high-pressure outlet air 68 is discharged from the rotor cavity 64 and delivered via an air outlet port 70 to the charge-air cooler 22. In the process of being compressed between the first and second rotors 60, 62 and being transformed into the relatively high-pressure outlet air 68, the temperature of the relatively low-pressure inlet air 66 is increased. The charge-air cooler 22 is configured to receive the outlet air 68 from the supercharger 20. As shown, the charge-air cooler 22 can include a first core or bank 22-1 and a second core or bank 22-2. Each bank 22-1, 22-2 can be configured to receive the outlet air 68 from the supercharger 20 and reduce temperature of the outlet air 68. From the charge-air cooler 22, the reduced temperature outlet air 68 can be conveyed to the IC engine 10, where the outlet air can be combined with fuel for subsequent combustion inside the combustion chambers 12 (shown in Figure 1).

[0020] The housing 32 can define a pressurized backflow cavity 72 configured to receive the outlet air 68 from the supercharger 20 and convey the outlet air to the charge-air cooler 22. The backflow cavity 72 can include a first curved, i.e., contoured with a predetermined radius, surface 74 leading in a first direction represented by an arrow 76 directly from the supercharger 20 to the charge-air cooler 22. The contour of the first curved surface 74 can be selected specifically to streamline and manage flow and minimize turbulence of the outlet air 68 in the first direction represented by the arrow 76 such that the outlet air flows in an efficient manner thereby increasing the throughput of the supercharging system 16.

[0021] The first curved surface 74 can include a short-side radius 78 (shown in Figure 6) shaped such that the flow of the outlet air 68 in the first direction represented by the arrow 76 can maintain attachment to the curved surface on the way to the charge-air cooler 22, and thus minimize turbulence. As can be seen from Figure 2, the term "short-side radius" refers to the side of the first curved surface 74 that generates the shortest airflow path between the supercharger 20 and the charge- air cooler 22. The contour of the first curved surface 74 can be selected empirically by testing the supercharging system 16 on an appropriately adapted airflow measurement bench. It will be appreciated in light of the disclosure that efficient flow of the outlet air 68 through the supercharging system 16 can effectively maximize the volume of air delivered to each combustion chamber 12 for each combustion cycle and, therefore, can increase operating efficiency of the engine 10.

[0022] The backflow cavity 72 can additionally include a cavity rib 80 disposed along a second curved surface 75 leading in a second direction represented by an arrow 77. The second curved surface 75 can be contoured with a predetermined radius that is different from the radius of the first curved surface 74. The second curved surface 75 can be located in a plane that is substantially orthogonal to the first curved surface 74. The cavity rib 80 can be configured to stiffen the housing 32, as well as can be configured to split the outlet air 68 along the second curved surface 75 into a first airflow portion or airstream 68-1 and a second airstream 68-2 and direct airstream 68-1 to the first bank 22-1 and the second airstream to the second bank 22-2 of the charge-air cooler 22. As shown in Figures 3 and 4, the cavity rib 80 can be defined by a shape 82 that has an external contour, wherein the shape can be seen expanding toward the first and second banks 22-1, 22-2 in the second direction represented by the arrow 77. The shape 82 can be specifically configured or formed to divide the outlet air 68 into the first airstream 68-1 and the second airstream 68-2 while limiting flow inefficiency, such as turbulence, and encouraging laminar flow in the first and second airstreams.

[0023] The backflow cavity 72 additionally includes a fillet 84 disposed around the base of the cavity rib 80 between the second curved surface 75 and the cavity rib. The fillet 84 can be configured to increase the stiffness of the cavity rib 80, while also smoothly directing the flow of each airstream 68-1 and 68-2 to the respective first and second banks 22-1, 22-2. As shown in Figures 4 and 5, the housing 32 can also include a cover 86 configured to enclose the backflow cavity 72 by being attached thereto and sealing to the housing 32. The cover 86 can also include a seal 88 and a cover rib 90 (shown in Figures 5 and 6). The cavity rib 80 can extend from the second curved surface 75 substantially to the cover rib 90. Additionally, the seal 88 can be disposed between the backflow cavity 72 and the cover 86, such that the cover is hermetically sealed to the backflow cavity via the seal. Accordingly, the cover 86 can be configured to cooperate with the housing 32 to streamline flow and minimize turbulence of the outlet air 68 in the first direction represented by the arrow 76. The cover 86 can contain many ornamental aspects independent of functional aspects disclosed herein.

[0024] The cover rib 90 is defined by a shape 92 that has an external contour. The shape 92 can be seen expanding in the second direction represented by the arrow 77 that is substantially orthogonal to the first direction represented by the arrow 76. The contour of the cover rib 90 is substantially complementary to the contour of the cavity rib 80, such that the contours of the two ribs substantially coincide when the cover 86 is assembled onto the backflow cavity 72. Furthermore, when the cover rib 90 is sealed to the cavity rib 80 via the seal 88, a substantially continuous airflow diverter structure is generated thereby. The airflow diverter thus configured from the cavity and cover ribs 80, 90 is configured to split the outlet air 68 into the first airstream 68-1 and the second airstream 68-2. The airflow diverter also directs the first airstream 68-1 to the first bank 22-1 of the charge-air cooler 22, and to direct the second airstream 68-2 to the second bank 22-2 of the charge-air cooler.

[0025] The cover 86 additionally includes a third curved surface 92 and a fillet 94 disposed between the third curved surface and the cover rib 90. The seal 88 can be an O-ring gasket that is inset in the cover 86 and configured to follow contour of the cover rib 90 to more closely generate the airflow diverter structure. As shown in Figures 4 and 5, the airflow diverter composed of the cavity rib 80 and the cover rib 90 extends from the curved second surface 75 to the cover 86 such that the airstreams 68-1 and 68-2 are fully separated on their way to the first and second banks 22-1, 22-2, respectively, of the charge-air cooler 22.

[0026] The detailed description and the drawings or figures are supportive and descriptive of the many aspects of the present disclosure. While certain aspects have been described in detail, various alternative aspects exist for practicing the invention as defined in the appended claims.

Claims

1. A supercharging system comprising:

a positive displacement pump defining a cavity configured to receive relatively low-pressure inlet air and discharge relatively high-pressure outlet air, and having first and second meshed rotors rotatably disposed in the cavity and configured to transform the relatively low-pressure inlet air into the relatively high- pressure outlet air;

a charge-air cooler configured to receive the outlet air from the pump and reduce temperature of the outlet air; and

a housing configured to accommodate the pump and the charge-air cooler; wherein:

the housing defines a backflow cavity configured to receive the outlet air from the pump and convey the outlet air to the charge-air cooler; and

the backflow cavity includes a first curved surface leading in a first direction from the pump to the charge-air cooler and configured to streamline flow and minimize turbulence of the outlet air in the first direction.

2. The supercharging system of claim 1, wherein the first curved surface includes a short-side radius shaped such that the flow of the outlet air in the first direction maintains attachment to the first curved surface on the way to the charge- air cooler.

3. The supercharging system of claim 1, wherein the backflow cavity additionally includes a cavity rib disposed along a second curved surface, and wherein the cavity rib is configured to stiffen the housing.

4. The supercharging system of claim 3, wherein the cavity rib is defined by a shape that expands in a second direction, and wherein the cavity rib is substantially orthogonal to the first direction.

5. The supercharging system of claim 3, wherein the backflow cavity additionally includes a fillet disposed between the second curved surface and the cavity rib.

6. The supercharging system of claim 3, wherein:

the housing includes a cover configured to enclose the backflow cavity; the cover includes a seal and a cover rib; and

the cavity rib extends from the second curved surface substantially to the cover rib, and wherein the cover is sealed to the backflow cavity via the seal.

7. The supercharging system of claim 6, wherein the seal is an O-ring gasket inset in the cover and configured to follow contour of the cover rib.

8. The supercharging system of claim 6, wherein:

the cover rib is defined by a shape having a contour;

the shape expands in the second direction and is substantially orthogonal to the first direction;

the cover rib is substantially complementary to the cavity rib; and the cover rib is sealed to the cavity rib via the seal, thereby generating a substantially continuous airflow diverter.

9. The supercharging system of claim 8, wherein:

the charge-air cooler includes a first bank and a second bank, each configured to receive the outlet air from the pump and reduce temperature of the outlet air; and

the airflow diverter is configured to split the outlet air into a first portion and a second portion, to direct the first portion of the outlet air to the first bank of the charge-air cooler, and to direct the second portion of the outlet air to the second bank of the charge-air cooler.

10. The supercharging system of claim 8, wherein the cover additionally includes a third curved surface and a fillet disposed between the third curved surface and the cover rib.

11. An internal combustion engine comprising:

a combustion chamber; and

a supercharging system including:

a positive displacement pump defining a cavity configured to receive relatively low-pressure inlet air and discharge relatively high-pressure outlet air; and having first and second meshed rotors rotatably disposed in the cavity and configured to transform the relatively low-pressure inlet air into the relatively high- pressure outlet air;

a charge-air cooler configured to receive the outlet air from the pump, reduce temperature of the outlet air, and supply the reduced temperature pressurized air to the combustion chamber;

a housing configured to accommodate the pump and the charge-air cooler; and

a cover configured to seal to the housing;

wherein:

the backflow cavity includes a first curved surface leading in a first direction from the pump to the charge-air cooler and configured to streamline flow and minimize turbulence of the outlet air in the first direction;

the cover is configured to enclose the backflow cavity and cooperate with the housing to streamline flow and minimize turbulence of the outlet air in the first direction.

12. The engine of claim 11, wherein the first curved surface includes a short-side radius shaped such that the flow of the outlet air in the first direction maintains attachment to the first curved surface on the way to the charge-air cooler.

13. The engine of claim 1 1, wherein the backflow cavity additionally includes a cavity rib disposed along a second curved surface, and wherein the cavity rib is configured to stiffen the housing.

14. The engine of claim 13, wherein the cavity rib is defined by a shape that expands in a second direction, and wherein the cavity rib is substantially orthogonal to the first direction.

15. The engine of claim 13, wherein the backflow cavity additionally includes a fillet disposed between the second curved surface and the cavity rib.

16. The engine of claim 13, wherein:

the cover includes a seal and a cover rib;

the cavity rib extends from the second curved surface substantially to the cover rib; and

the cover is sealed to the backflow cavity via the seal.

17. The engine of claim 16, wherein the seal is an O-ring gasket inset in the cover and configured to follow contour of the cover rib.

18. The engine of claim 16, wherein:

the cover rib is defined by a shape having a contour;

19. The engine of claim 18, wherein:

20. The engine of claim 18, wherein the cover additionally includes a third curved surface and a fillet disposed between the third curved surface and the cover rib.