HOUSING FOR AN INTERNAL COMBUSTION ENGINE

Abstract

In one exemplary embodiment of the invention, a housing for an internal combustion engine includes a manifold section configured to receive an exhaust gas flow from cylinders of the internal combustion engine and a turbine section, wherein the turbine section and manifold section are a single member. Further, the housing includes a volute chamber within the turbine section configured to direct the exhaust gas flow to a turbine wheel disposed about a turbine axis and a circumferential septum positioned inside the volute chamber to separate two chambers that are substantially nested about the turbine wheel.

Description

FEDERAL RESEARCH STATEMENT

This invention was made with Government support under Agreement No. DE-FC26-07NT43271, awarded by the Department of Energy. The U.S. Government has certain rights in the invention.

FIELD OF THE INVENTION

The subject invention relates to internal combustion engines, and, more particularly, to turbocharger housings for internal combustion engines.

BACKGROUND

An engine control module of an internal combustion engine controls the mixture of fuel and air supplied to combustion chambers of the engine. After the spark plug ignites the air/fuel mixture, combustion takes place and, later, the combustion gases exit the combustion chambers through exhaust valves. The combustion gases are directed by an exhaust manifold to a catalytic converter or other exhaust after treatment systems.

A turbocharger can be utilized to receive the exhaust gases from the exhaust manifold to provide enhanced performance and reduced emissions for the engine. In addition, twin scroll technology is often used to further enhance the performance of a turbocharged engine; in particular inline four or six cylinder engines as well as those having “V” or “flat” architectures. In engines featuring twin scroll or twin turbo technology, the exhaust manifold of the engine is designed to group the cylinders so combustion events of the cylinders in each group are separated to minimize cylinder-to-cylinder exhaust flow interference, thereby improving exhaust pulse integrity. For example, cylinders are grouped to provide sequences of high pulse energy to drive the turbine wheel as each cylinder experiences combustion. Thus, a first group of cylinders that is substantially out of phase (substantially not firing) with respect to a second group of cylinders (substantially firing) does not interfere with or degrade an exhaust pulse ignited by the second group of cylinders. Accordingly, twin scroll turbocharger systems have forces imparted on the turbine wheel more frequently to improve turbine performance. In addition, engines utilizing twin scroll technology may have packaging and assembly constraints due to the complexity of separated exhaust passages. Additional components may be used to make factory assembly of the twin scroll turbocharger possible, but these additional components can increase overall complexity, materials and cost of the engine.

SUMMARY OF THE INVENTION

In one exemplary embodiment of the invention, a housing for an internal combustion engine includes a manifold section configured to receive an exhaust gas flow from cylinders of the internal combustion engine and a turbine section, wherein the turbine section and manifold section are a single member. Further, the housing includes a volute chamber within the turbine section configured to direct the exhaust gas flow to a turbine wheel disposed about a turbine axis and a circumferential septum positioned inside the volute chamber to separate two chambers that are substantially nested about the turbine wheel.

In another exemplary embodiment of the invention, an internal combustion engine includes a plurality of cylinders in a cylinder head, a first portion of a turbine housing coupled to the cylinder head and in fluid communication with the plurality of cylinders and a second portion of the turbine housing including a volute chamber housing a turbine wheel disposed about a turbine axis. The engine also includes a septum positioned inside the volute chamber to form a first chamber and second chamber, wherein the first chamber is in fluid communication with the turbine wheel and a first group of cylinders and the second chamber is in fluid communication with the turbine wheel and a second group of cylinders.

The above features and advantages, and other features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, advantages and details appear, by way of example only, in the following detailed description of embodiments, the detailed description referring to the drawings in which:

FIG. 1 is a schematic diagram of an embodiment of an internal combustion engine;

FIG. 2 is a perspective view of an embodiment of a housing for the internal combustion engine; and

FIG. 3 is a perspective view of another embodiment of a housing for the internal combustion engine.

DESCRIPTION OF THE EMBODIMENTS

The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

In accordance with an exemplary embodiment of the invention, FIG. 1 illustrates an exemplary internal combustion engine 100, in this case an in-line four cylinder engine, including an engine block and cylinder head assembly 104, an exhaust system 106, a turbocharger 108 and a controller 110. Coupled to the engine block and cylinder head assembly 104 is a housing 118 which may be external to the engine block and cylinder head assembly 104. In addition, the engine block and cylinder head assembly 104 includes cylinders 114 wherein the cylinders 114 receive a combination of combustion air and fuel. The combustion air/fuel mixture is combusted resulting in reciprocation of pistons (not shown) located in the cylinders 114. The reciprocation of the pistons rotates a crankshaft (not shown) to deliver motive power to a vehicle powertrain (not shown) or to a generator or other stationary recipient of such power (not shown) in the case of a stationary application of the internal combustion engine 100. The combustion of the air/fuel mixture causes a flow of exhaust gas through the housing 118 and turbocharger 108 and into the exhaust system 106. In an embodiment, the turbocharger 108 includes a compressor wheel 123 and a turbine wheel 124 coupled by a shaft 125 rotatably disposed in the turbocharger 108.

The exhaust system 106 may include “close-coupled” catalysts 126 and 128 as well as an under floor exhaust treatment system 130. The exhaust gas 132 flows through the exhaust system 106 for the removal or reduction of pollutants and is then released into the atmosphere. In an exemplary internal combustion engine 100, the controller 110 is in signal communication with the turbocharger 108, a charge cooler 144 and the exhaust system 106, wherein the controller 110 is configured to use various signal inputs to control various processes, such as the amount of boost supplied to the engine by the turbocharger 108. As used herein the term controller refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.

Still referring to FIG. 1, the exhaust gas flow 122 drives the turbine wheel 124 of turbocharger 108, thereby providing energy to rotate the compressor wheel 123 to create a compressed air charge 142. In an exemplary embodiment, the compressed air charge 142 is cooled by the charge cooler 144 and is routed through the conduit 146 to an intake manifold 148. The compressed air charge 142 provides additional combustion air (when compared to a non-turbocharged, normally aspirated engine) for combustion with fuel in the cylinders 114, thereby improving the power output and efficiency of the internal combustion engine 100. In addition, exemplary embodiments of turbocharger 108 utilize twin scroll or twin turbo technology. The exemplary turbocharger 108 includes a twin scroll turbine housing 118 using two substantially separate chambers to direct exhaust gas into the turbocharger 108. The housing 118 is coupled to the cylinder head 104 and is configured to receive the exhaust gas flow 122 and direct it to the turbine wheel 124. The housing 118 is a single member or component with a manifold section 120 and a turbine section 119 wherein the turbine wheel 124 is disposed in the turbine section 119. In an embodiment, the housing 118 may be referred to as a member with a manifold section 120 integrated with a turbine section 119. By forming the manifold section 120 and turbine section 119 from a single member, assembly and packaging of the turbocharger 108 and cylinder block 104 are simplified. Further, embodiments of the housing 118 also improve performance of the twin scroll turbocharger 108 by reducing interference or “cross-talk” between exhaust pulses from exhaust chambers or passages within the housing 118. In embodiments, the housing 118 may be coupled to additional housings containing the compressor wheel 123 and shaft 125.

The turbocharger 108 includes twin scroll technology that separates exhaust pulses from the cylinders 114 by as many degrees as possible in relation to a firing order of the cylinders to maintain exhaust pulse energy received by the turbine wheel 124. The twin scroll turbocharger 108 reduces lag, decreases exhaust backpressure on the top end of the combustion cycle and increases fuel economy. The twin scroll design restricts fluid communication of combustion exhaust gases 122 from an out of phase cylinder (e.g., at a different combustion cycle position) from reducing the energy of an exhaust pulse provided by a recently fired cylinder. Accordingly, the housing 118 is designed to provide substantially separate fluid communication from two groups of cylinders 114. In one exemplary embodiment, “in phase” describes cylinders 114 with substantially similar positions in the combustion cycle at a point in time such that, for example, the first firing cylinder is out of phase with reference to the third firing cylinder. Thus, an exemplary in-line four cylinder engine has cylinders 114 in the following order 134-136-138-140. The firing order is then as follows, with the cylinder number shown in brackets: 1[134]-3[138]-4[140]-2[136]. Fluid communication and cross-talk between the passages of the adjacent and substantially out of phase cylinders can degrade exhaust pulse energy. Thus, in an embodiment, the housing 118 has a first group of cylinders 134, 140 and a second group of cylinders 136, 138, wherein separate chambers for the two cylinder groups reduce cross-talk to improve turbocharger 108 performance.

FIG. 2 is a perspective view of an embodiment of a housing 118 wherein a portion is removed to show details thereof The housing 118 includes a manifold section 120 and a turbine section 119, wherein the sections are integrated into a single member. The manifold section 120 is configured to couple to the cylinder head 104 (FIG. 1) along couplings 206 which lead to separate conduits or passages 222, 224, 226 and 228 within the housing 118 for receiving exhaust gas flow from cylinders 134, 136, 138, 140 of the engine 100 (FIG. 1), as described below. The turbine section 119 has a volute chamber 208 configured to house the turbine wheel 124 (FIG. 1) in a cavity 209. The volute chamber 208 is divided by a septum 210 into an outer chamber 212 and an inner chamber 214. The inner chamber 214 may be described as nested within the outer chamber 212. In an embodiment, the outer chamber 212 and inner chamber 214 are substantially concentrically disposed about a turbine axis 216. The septum 210 is configured to substantially separate groups of exhaust pulses directed to the turbine wheel 124 to reduce cross-talk and interference. Accordingly, the exemplary twin scroll turbocharger 108 (FIG. 1) has an improved performance due to the housing 200 maintaining integrity of exhaust pulses generated by the cylinders 114 (FIG. 1).

As depicted, the cylinders 114 direct exhaust gas flow 122 (FIG. 1) through an outer passage 218 and an inner passage 220 to the outer chamber 212 and inner chamber 214, respectively. In an embodiment, the outer chamber 212 is a portion of the outer passage 218 that directs the exhaust gas to the turbine wheel 124. Similarly, the inner chamber 214 is a portion of the inner passage 220 that directs the exhaust gas to the turbine wheel 124. As depicted, passages 222, 224, 226, 228 are configured to receive the exhaust gas flow 122 from respective cylinders 134, 136, 138, 140 of the engine 100 (FIG. 1) and are arranged in groups to preserve the integrity of exhaust pulses. Thus, exhaust passages 222 and 228 direct exhaust gas flow 122 to the inner passage 220. Further, exhaust passages 224 and 226 direct exhaust gas flow 122 to the outer passage 218. In embodiments, the cylinders and corresponding passages may be grouped differently based on engine configuration, firing order, packaging constraints and other factors.

The exemplary single member or piece housing 118 provides simplified packaging, production and assembly for the turbocharger 108 and the engine 100. Further, the single member design reduces materials used for the twin scroll turbocharger 108 to reduce weight and improve thermal communication along the exhaust flow path (e.g. through the turbocharger 108 to exhaust treatment apparatus). Less volume and mass of material reduces the amount of thermal energy absorbed by the housing 118 prior to the exhaust gas flow 122 into the exhaust system 106 (FIG. 1). Improved thermal communication improves performance of the exhaust system 106 during startup by preserving thermal energy to heat the close coupled catalysts 126, 128, thereby improving catalyst performance. The integrated housing 118 including the manifold and turbine sections 120, 119 may be made by any suitable process, such as investment casting, sand casting, machining and/or any other method. The housing 118 comprises any suitable durable and substantially lightweight material, such as a steel alloy. In an embodiment, a part of the outer chamber 212 is defined by the septum 210 and the outer wall of the volute chamber 208. Further, the septum 210 defines the outer portion of a part of the inner chamber 214. Accordingly, the septum 210 is configured to prevent radial (i.e., in a radial direction) fluid communication between the inner and outer chambers 214, 212 for at least a portion of the circumference of the volute chamber 208. In embodiments, the inner chamber 214 may be described as radially within the outer chamber 212. Further, the septum 210 may be described as a circumferentially extending septum.

FIG. 3 is a perspective view of another embodiment of a housing 300 wherein a portion is cut away to show details thereof The housing 300 includes a manifold section 302 and a turbine section 304, wherein the sections are integrated into a single member. The manifold section 302 is configured to couple to the cylinder head 104 (FIG. 1) along couplings or mounts 306 which include passages for exhaust gas flow from the engine 100 (FIG. 1). The turbine section 304 forms a volute chamber 308 configured to house the turbine wheel 124 (FIG. 1) in a cavity 309. The volute chamber 308 is divided by a septum 310 into a first chamber 312 and a second chamber 314. The second chamber 314 may be described as axially adjacent to the first chamber 312. The septum 310 is configured to substantially separate or isolate exhaust pulses directed to the turbine wheel 124 to reduce cross-talk and interference. As depicted, the septum 310 may be described as a radial septum dividing the adjacent first chamber 312 and second chamber 314. The exemplary twin scroll turbocharger 108 (FIG. 1) has an improved performance due to the arrangement of the septum 310 and housing 300 that maintains exhaust pulse integrity within chambers 312 and 314.

As depicted, the cylinders 114 direct exhaust gas flow 122 (FIG. 1) through a first passage 318 and a second passage 320 to the first chamber 312 and second chamber 314, respectively. In an embodiment, the first chamber 312 is a portion of the first passage 318 that directs the exhaust gas to the turbine wheel 124. Similarly, the second chamber 314 is a portion of the second passage 320 that directs the exhaust gas to the turbine wheel 124. As depicted, exhaust passages 322, 324, 326 and 328 are configured to receive the exhaust gas flow 122 from respective cylinders 134, 136, 138, 140 of the engine 100 (FIG. 1). The exhaust passages 322 and 328 are in fluid communication with the first passage 318 while the exhaust passages 324 and 326 are in fluid communication with the second passage 320. Exhaust pulse integrity is maintained by grouping the cylinders in the passages 318, 320 and by the septum 310 providing a radial barrier to reduce fluid communication and cross-talk between the flow from the cylinder groups. As depicted, fluid communication from the first and second chambers 312, 314 to the turbine wheel 124 (FIG. 1) via adjacent circumferential passages is provided on each side of the radial septum 310. In addition, the first and second chambers 312, 314 decrease in size from a first radial position 330 (about 3 o'clock when viewed from the left side) as compared to a second radial position 332 (about 9 o'clock).

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the present application.

Claims

1. A housing for an internal combustion engine, the housing comprising:

a manifold section configured to receive an exhaust gas flow from cylinders of the internal combustion engine;

a turbine section, wherein the turbine section and manifold section comprise a single member;

a volute chamber within the turbine section configured to direct the exhaust gas flow to a turbine wheel disposed about a turbine axis; and

a circumferential septum positioned inside the volute chamber to separate two chambers that are substantially nested about the turbine wheel.

2. The housing of claim 1, wherein the manifold section is coupled to a cylinder head housing the cylinders.

3. The housing of claim 1, wherein the circumferential septum separates a first chamber from a second chamber in the volute chamber, wherein the first chamber is radially inside the second chamber.

4. The housing of claim 3, wherein the first chamber is in fluid communication with a first group of cylinders and the second chamber is in fluid communication with a second group of cylinders.

5. The housing of claim 3, wherein the circumferential septum is configured to prevent radial fluid communication between the first and second chambers for at least a portion of the volute chamber.

6. The housing of claim 3, wherein at least a portion of the second chamber is defined by an outer wall of the volute chamber and the circumferential septum.

7. The housing of claim 1, wherein the housing is configured for use with a twin scroll turbocharger.

8. The housing of claim 1, wherein the two chambers are substantially concentric about the turbine axis.

9. A housing for an internal combustion engine, the housing comprising:

a manifold section configured to receive an exhaust gas flow from cylinders of the internal combustion engine;

a turbine section, wherein the turbine section and the manifold section comprise a single member;

a volute chamber within the turbine section configured to direct the exhaust gas flow to a turbine wheel disposed about a turbine axis; and

a septum positioned inside the volute chamber to form a first chamber in fluid communication with the turbine wheel and a first group of cylinders and a second chamber in fluid communication with the turbine wheel and a second group of cylinders.

10. The housing of claim 9, wherein the manifold section is coupled to a cylinder head housing the cylinders.

11. The housing of claim 9, wherein the septum comprises a substantially radial septum with respect to the turbine axis.

12. The housing of claim 9, wherein the first and second chambers are nested about the turbine wheel and the septum comprises a substantially circumferential septum with respect to the turbine axis.

13. The housing of claim 12, wherein the circumferential septum is configured to prevent fluid communication between the first and second chambers for at least a portion of the volute chamber.

14. The housing of claim 9, wherein the housing is configured for use with a twin scroll turbocharger.

15. An internal combustion engine, comprising:

a plurality of cylinders in a cylinder head;

a first portion of a turbine housing coupled to the cylinder head and in fluid communication with the plurality of cylinders;

a second portion of the turbine housing comprising a volute chamber housing a turbine wheel disposed about a turbine axis; and

a septum positioned inside the volute chamber to form a first chamber and second chamber, wherein the first chamber is in fluid communication with the turbine wheel and a first group of cylinders and the second chamber is in fluid communication with the turbine wheel and a second group of cylinders.

16. The internal combustion engine of claim 15, wherein the septum comprises a substantially radial septum with respect to the turbine axis.

17. The internal combustion engine of claim 16, wherein the first and second chambers are in fluid communication with the turbine wheel via axially adjacent circumferential passages on each side of the radial septum.

18. The internal combustion engine of claim 15, wherein the first and second chambers are nested about the turbine wheel and the septum comprises a substantially circumferential septum with respect to the turbine axis.

19. The internal combustion engine of claim 18, wherein the circumferential septum is configured to prevent radial fluid communication between the first and second chambers for at least a portion of the volute chamber.

20. The internal combustion engine of claim 15, wherein the turbine housing is configured for use with a twin scroll turbocharger.