MANIFOLD

Abstract

A manifold system for an internal combustion engine, comprising a housing designed as a collecting manifold, which housing has two inlet openings and an outlet opening for connecting two outlets of an internal combustion engine to an exhaust gas system in regard to flow and at least one connection opening provided on the housing for connecting to an outer shell of a double-shell air-gap-insulated manifold, and comprising at least one air-gap-insulated manifold connected to the connection opening, which air-gap-insulated manifold has an inner shell having an inlet opening for connecting to an outlet of the internal combustion engine in regard to flow and having an outer shell, wherein all air-gap-insulated manifolds are completely formed from sheet metal and are structurally or geometrically identical and, on the housing, the size of a distance A2 between one of the two inlet openings and the outlet opening is between 30 mm and 300 mm or between 50 mm and 120 mm.

Claims

1. A manifold system for an internal combustion engine with a) a housing designed as a collecting manifold, with two inlet openings and an outlet opening for fluidically connecting two outlets of an internal combustion engine to an exhaust gas system, b) and at least one connection opening provided on the housing for connecting to an outer shell of a double shell air gap insulated manifold, as well as c) at least one air gap insulated manifold connected to the connection opening, having an inner shell with an inlet opening for the fluidic connection to one outlet of the internal combustion engine and with an outer shell, wherein d) all air gap insulated manifolds are completely formed from sheet metal and are structurally or geometrically identical and e) a size of a distance (A2) on the housing between one of the two inlet openings and the outlet opening is between 30 mm and 300 mm.

2. The manifold system according to claim 1, wherein the distance (A2) is dimensioned as a function of sound waves of the exhaust gas whose wavelength (L) of sound is calculated by n*A2 or 1/n*A2, n being an element of natural numbers, but not zero.

3. The manifold system according to claim 1, wherein the two inlet openings within the housing stand in a fluidic and acoustic exchange with each other.

4. The manifold system according to claim 1, wherein the two inlet openings are separated in the housing by a duct wall and two flow ducts are formed by the duct wall, wherein both flow ducts empty into the outlet opening at the end of the duct wall and the two flow ducts stand in fluidic and acoustic exchange via an opening or perforation provided upstream from the outlet opening in the duct wall.

5. The manifold system according to claim 4, wherein the opening or the perforation has an overall cross section between 25 mm.sup.2 and 50 mm.sup.2.

6. The manifold system according to claim 1, wherein the housing is fashioned as a single-piece casting.

7. The manifold system according to claim 6, wherein the housing is formed from a low-alloy gray cast iron with a carbon content of at least 1.00 wt. % and further alloy additions each with a mean content of not more than 50.00 wt. %.

8. The manifold system according to claim 1, wherein the housing is formed entirely of sheet metal, as a multiple piece and double-walled part, and also air gap insulated with an outer housing and at least one inner housing, the connection opening being provided on the outer housing.

9. The manifold system according to claim 8, wherein the air gap insulated manifold has a connection opening and an outlet opening, wherein the air gap insulated manifold is directly connected to the housing by its connection opening and is connected across its outlet opening to the connection opening of another air gap insulated manifold.

10. The manifold system according to claim 9, wherein the outlet opening of the outermost air gap insulated manifold is closed by a lid.

11. The manifold system according to claim 1, wherein the air gap insulated manifold is joined to the housing by a bonding technique.

12. The manifold system according to claim 1, wherein the housing has only one connection opening by which two air gap insulated manifolds are connected directly or indirectly.

13. The manifold system according to claim 1, wherein the housing connects the outlet openings to a housing of a turbocharger and for this purpose forms a load-bearing structural part arranged between an engine block and the turbocharger.

14. A system consisting of a manifold system according to claim 1 and an internal combustion engine.

15. The manifold system according to claim 2, wherein the two inlet openings within the housing stand in a fluidic and acoustic exchange with each other.

16. The manifold system according to claim 1, wherein the size of the distance (A2) on the housing between one of the two inlet openings and the outlet opening is between 50 mm and 120 mm.

17. The manifold system according to claim 11, wherein the bonding technique is welding, soldering, or gluing.

18. The manifold system according to claim 2, wherein the two inlet openings within the housing stand in a fluidic and acoustic exchange with each other; wherein the two inlet openings are separated in the housing by a duct wall and two flow ducts are formed by the duct wall, wherein both flow ducts empty into the outlet opening at the end of the duct wall and the two flow ducts stand in fluidic and acoustic exchange via an opening or perforation provided upstream from the outlet opening in the duct wall; and wherein the opening or the perforation has an overall cross section between 25 mm.sup.2 and 50 mm.sup.2.

19. The manifold system according to claim 18, wherein the housing is fashioned as a single-piece casting; wherein the housing is formed from a low-alloy gray cast iron with a carbon content of at least 1.00 wt. % and further alloy additions each with a mean content of not more than 50.00 wt. %.

20. The manifold system according to claim 19, wherein the air gap insulated manifold is joined to the housing by a bonding technique; wherein the housing has only one connection opening by which two air gap insulated manifolds are connected directly or indirectly; and wherein the housing connects the outlet openings to a housing of a turbocharger and for this purpose forms a load-bearing structural part arranged between an engine block and the turbocharger.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Further advantages and details of the invention are explained in the patent claims and in the specification and represented in the figures. There are shown:

[0023] FIG. 1a, a sectional view of a housing fashioned as a collecting manifold with flow ducts standing in interaction;

[0024] FIG. 1b, a side view of the collecting manifold of FIG. 1a;

[0025] FIG. 2, a sectional view of a manifold system with a collecting manifold with flow ducts standing in interaction and four air gap insulated manifolds;

[0026] FIG. 3, a sectional view of a manifold system with a collecting manifold with flow ducts standing in interaction and two air gap insulated manifolds;

[0027] FIG. 4, a double-wall collecting manifold made of sheet metal;

[0028] FIG. 5, a sectional view of a flange connection between collecting manifold and air gap insulated manifold;

[0029] FIG. 6, a sectional view of a connection between collecting manifold and air gap insulated manifold via an inlay in the collecting manifold;

[0030] FIG. 7a, a view of a collecting manifold with V-bank clamp arranged at both sides;

[0031] FIG. 7b, a sectional view of a V-bank clamp connection between collecting manifold and air gap insulated manifold;

[0032] FIG. 8a, a schematic representation of the distance between an inlet opening and the outlet opening in a collecting manifold as seen from above;

[0033] FIG. 8b, a schematic representation of the distance between an inlet opening and the outlet opening in a collecting manifold in side view.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1a shows a sectional view of a housing 2 fashioned as a collecting manifold with flow ducts 25, 26 standing in interaction. The housing 2 is formed from a gray cast iron and in addition to two inlet openings 20, 21 for connecting the housing 2 to outlets (not represented) of an internal combustion engine it also has two connection openings 22, 23, each for an air gap insulated manifold 31, 32. From the two inlet openings 20, 21, two flow ducts 25, 26 arranged alongside each other and partly separated by a duct wall 27 extend inside the housing 2 up to an outlet opening 24 of the housing, represented in FIG. 1b. To improve the acoustic properties of the collecting manifold 2, the two flow ducts 25, 26 stand in interaction with each other across an opening 271 in the duct wall 27.

[0035] In the sample embodiment of a manifold system 1 shown in FIG. 2, the housing 2 is not symmetrical in design, but as in the sample embodiment of FIGS. 1a and 1b it has two connection openings 23 for one air gap insulated manifold 31, 32 apiece as well as the two inlet openings 20, 21. From the two inlet openings 20, 21, two flow ducts 25, 26 extend inside the housing 2 up to the outlet opening 24 of the housing 2. Here as well, the two flow ducts 25, 26 are partly separated in their interaction by a duct wall 27. The average length of the two flow ducts 25, 26 represented by arrows corresponds to a distance A2, more closely described in FIGS. 8a and 8b, between the respective inlet opening 20, 21 and the outlet opening 24. In this sample embodiment, the distances A2 differ by a factor of 1.6.

[0036] FIG. 3 shows a housing 2 for a manifold system 1 for an internal combustion engine with four cylinder arranged in line. The housing 2 has only one connection opening 22 for an air gap insulated manifold 30. In this housing 2, no reduction in the interaction between the two flow ducts 25, 26 by a duct wall 27 is provided.

[0037] FIG. 4 shows an air gap insulated housing 2, which is fashioned as a collecting manifold. The housing 2 has an outer housing 28 and two inner housings 29 integrated in the outer housing 28.

[0038] The housing 2 is fashioned as a load-bearing part and connects the outlets of the engine block (not represented) to a housing of a turbocharger (not represented). On one or both sides, air gap insulated manifolds 30-33 are connected to the housing 2, not having any load-bearing or statically relevant function.

[0039] The air gap insulated manifolds 30-33 represented in the two sample embodiments of FIGS. 2 and 3 are formed from sheet metal and are geometrically and structurally identical. Thanks to the identical shape of all air gap insulated manifolds 30-33, the acoustic properties at the most important operating points of the internal combustion engine are improved, because the vibration and resonance behavior is identical in all air gap insulated manifolds 30-33. A different configuration would have resulted in different vibration and resonance behavior.

[0040] Furthermore, the identical shape has the benefit that, in combination with a housing 2 formed as a collecting manifold 2 for two outlets, a manifold system 1 for a 4-cylinder internal combustion engine supplemented with two air gap insulated manifolds 30, 33 can be used for a 6-cylinder internal combustion engine. The last air gap insulated manifold 30, 33 in the series is closed by a lid 4. The connection between the air gap insulated manifolds 30-33 and between the lid 4 and the respective air gap insulated manifold 30, 33 is formed as a welded connection.

[0041] The identical air gap insulated manifolds 30 have an inner shell 34 and an outer shell 35 surrounding the inner shell 34. The two shells 34, 35 extend from a respective inlet opening 36 in the flow direction to a respective outlet opening 37 and contrary to the flow direction to a respective connection opening 38. At the respective openings 36-38, the inner shell 34 and the outer shell 35 are joined together flush in one of the flow directions.

[0042] When the respective air gap insulated manifold 30-33 is connected to the housing 2, the outer shell 35 is critical for the particular joining technique. As a rule, the inner shell 34 is only inserted into the housing 2.

[0043] The connection between the housing 2 and the outer shell 35 of the respective air gap insulated manifold 31, 32 is preferably formed as a welded connection. Alternatively to this, a connection as a flange 7 or inlay 8 or V-band clamp 6 is provided according to FIG. 5-7b.

[0044] The distance A2 represented in FIGS. 8a and 8b between the respective inlet opening 20, 21 and the outlet opening 24 is also dependent on the size ratios of the respective diameter De of the inlet openings 20, 21 to the diameters Da of the outlet opening 24. For an optimal acoustic adaptation to the most important operating points of the internal combustion engine, especially in regard to the critical rpm for the most important load regions, the distances A2, the diameter ratios De, Da and the identical shape of the air gap insulated manifolds 30-33 are thus critical.