Manifold

Abstract

A manifold system for an internal combustion engine, having a housing, which is designed as a collecting manifold and which has two inlet openings and an outlet opening for the flow connection of two outlets of an internal combustion engine to an exhaust system and at most two connection openings provided on the housing for connecting a double-shell inner air-gap-insulated manifold. An exhaust system is developed in such a way that, at the same time, the tone of the exhaust gas noise and thus of the exhaust system is optimized over a plurality of important rotational speed ranges of the internal combustion engine by a modular assembly. For this purpose, at least one separate inner air-gap-insulated manifold having a connection opening, an inlet opening, and an outlet opening is provided, which is connected to the housing by the outlet opening, and at least one separate outer air-gap-insulated manifold having an inlet opening and an outlet opening is connected to the connection opening of the inner air-gap-insulated manifold. All air-gap-insulated manifolds are completely formed of sheet metal, and each air-gap-insulated manifold has a separate one- or multi-part inner shell and a one- or multi-part separate outer shell. All inner air-gap-insulated manifolds are structurally or geometrically identical and all outer air-gap-insulated manifolds are structurally or geometrically identical, wherein the inner air-gap-insulated manifolds are not structurally identical and not geometrically identical to the outer air-gap-insulated manifolds.

Claims

1. A manifold system for an internal combustion engine, comprising: a) a housing configured as a collecting manifold, which housing has two inlet openings and an outlet opening for fluidically connecting two outlets of an internal combustion engine to an exhaust gas system, and b) a maximum of two connection openings provided on the housing for connecting a double-shell inner air gap insulated manifold, wherein c) at least one separate inner air gap insulated manifold is provided with a connection opening, an inlet opening and an outlet opening, said separate inner air gap insulated manifold being connected with the outlet opening to the housing, and d) at least one separate outer air gap insulated manifold is provided with an inlet opening and an outlet opening, said separate outer air gap insulated manifold being connected with the outlet opening to the connection opening of the inner air gap insulated manifold, and e) all air gap insulated manifolds are completely formed from sheet metal and have a separate single-piece or multiple-piece inner shell and a separate single-piece or multiple-piece outer shell, and f) all inner air gap insulated manifolds are geometrically identical and all outer air gap insulated manifolds are geometrically identical, and g) wherein the inner air gap insulated manifolds are not structurally or geometrically identical to the outer air gap insulated manifolds.

2. The manifold system according to claim 1, wherein 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.

3. The manifold system according to claim 2, wherein the size of a distance (A2) on the housing between one of the two inlet openings and the outlet opening is between 50 mm and 120 mm.

4. 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.

5. The manifold system according to claim 4, wherein the housing is configured as a single-piece casting.

6. The manifold system according to claim 5, 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 a leakage in the form of an opening or perforation provided upstream of the outlet opening in the duct wall.

7. The manifold system according to claim 6, wherein the opening or the perforation has an overall cross section between 4 mm.sup.2 and 500 mm.sup.2.

8. The manifold system according to claim 4, wherein the housing is formed entirely of sheet metal, as a double-walled part, and also air gap insulated with a single-piece or multiple-piece outer housing and a single-piece or multiple-piece inner housing.

9. The manifold system according to claim 8, wherein the inner housing at the connection openings is mated with the inner shell of the inner air gap insulated manifold at the outlet opening of the inner air gap insulated manifold and a leakage in the form of a joining gap having an average width between 0.4 mm and 1.2 mm is thereby formed between the inner housing and the inner shell, and wherein the outer air gap insulated 1) do not have a connection opening for connecting a further double shell air gap insulated manifold and 2) are configured in the form of an arc.

10. A system consisting of the manifold system according to claim 9, and an internal combustion engine.

11. 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.

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

13. The manifold system according to claim 12, 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 a leakage in the form of an opening or perforation provided upstream of the outlet opening in the duct wall.

14. The manifold system according to claim 13, wherein the opening or the perforation has an overall cross section between 4 mm.sup.2 and 500 mm.sup.2.

15. The manifold system according to claim 1, wherein the housing is formed entirely of sheet metal, as a double-walled part, and also air gap insulated with a single-piece or multiple-piece outer housing and a single-piece or multiple-piece inner housing.

16. The manifold system according to claim 15, wherein the inner housing at the connection openings is mated with the inner shell of the inner air gap insulated manifold at the outlet opening of the inner air gap insulated manifold and a leakage in the form of a joining gap having an average width between 0.4 mm and 1.2 mm is thereby formed between the inner housing and the inner shell.

17. The manifold system according to claim 1, wherein the outer air gap insulated manifolds 1) do not have a connection opening for connecting a further double shell air c.sub.lap insulated manifold and 2) are configured in the form of an arc.

18. The manifold system according to claim 1, wherein the housing has only one connection opening.

19. 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 the engine block and the turbocharger.

20. A system consisting of the manifold system according to claim 1, and an internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIG. 1a, a sectional view of a housing configured as a collecting manifold with flow ducts being in interaction;

(3) FIG. 1b, a side view of the collecting manifold of FIG. 1a;

(4) FIG. 2, a sectional view of a manifold system with a collecting manifold with flow ducts being in interaction and two inner and two outer air gap insulated manifolds;

(5) FIG. 3, a sectional view of a manifold system with a collecting manifold with flow ducts being in interaction and an inner air gap insulated manifold and an outer air gap insulated manifold;

(6) FIG. 4, a double-wall collecting manifold made of sheet metal;

(7) FIG. 5, a sectional view of a flange connection between collecting manifold and air gap insulated manifold;

(8) FIG. 6, a sectional view of a connection between collecting manifold and air gap insulated manifold via an inlay in the collecting manifold;

(9) FIG. 7a, a view of a collecting manifold with V-bank clamp arranged at both sides;

(10) FIG. 7b, a sectional view of a V-bank clamp connection between collecting manifold and air gap insulated manifold;

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

(12) 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

(13) According to all of the embodiment examples a housing 2 is provided, having two inlet openings 20, 21 for connecting the housing 2 to outlets (not represented) of an internal combustion engine as well as one to two connection openings 22, 23 for connecting one air gap insulated manifold 30-31 each. Within the context of the cylinder sequence of an internal combustion engine having inner and outer cylinders, the inner air gap insulated manifolds 31, 32 in each case are arranged between the housing 2 and an outer air gap insulated manifold 30, 33, and the outer air gap insulated manifolds 30, 33 are arranged opposite the housing 2 on the respective inner air gap insulated manifold 31, 32.

(14) FIG. 1a shows a sectional view of a housing 2 configured as a collecting manifold with flow ducts 25, 26 being in interaction. The housing 2 is formed from a gray cast iron and as well as the 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 inner 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 2, represented in FIG. 1b. To improve the acoustic properties of the collecting manifold 2, the two flow ducts 25, 26 interact with each other across a leakage formed as an opening 51 in the duct wall 27, which allows so-called crosstalk.

(15) In the embodiment example of a manifold system 1 shown in FIG. 2, the housing 2 is not symmetrical in design, but as in the embodiment example of FIGS. 1 a and 1 b it has two connection openings 23 for one inner air gap insulated manifold 31, 32 each as well as the two inlet openings 20, 21. An outer air gap insulated manifold 30, 33 is connected with its outlet opening 37a to the respective inner air gap insulated manifold 31, 32 to the connection opening 38i thereof. The inner air gap insulated manifolds 31, 32 are all configured geometrically identically in a T shape with three openings 36i, 37i, 38i. The outer air gap insulated manifolds 30, 33 are configured geometrically identically to one another in the form of an arc having just two openings 36a, 37a.

(16) From the two inlet openings 20, 21 of the housing 2, 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 embodiment example, the distances A2 differ by a factor of 1.6.

(17) FIG. 3 shows a housing 2 for a manifold system 1 for an internal combustion engine with four cylinders arranged in line. The housing 2 has only one connection opening 22 for an inner air gap insulated manifold 31 with a T-shaped geometry. An outer air gap insulated manifold 30 in the form of an arc is connected to this inner air gap insulated manifold 31. In this housing 2, no reduction in the interaction between the two flow ducts 25, 26 by a duct wall 27 is provided.

(18) FIG. 4 shows an air gap insulated housing 2, which is configured as a collecting manifold. The housing 2 has an outer housing 28 and two inner housings 29 integrated in the outer housing 28.

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

(20) All air gap insulated manifolds 30 have an inner shell 34i, 34a and an outer shell 35i, 35a surrounding the inner shell 34i, 34a. At least at the respective inlet openings 36i, 36a, the respective inner shell 34i, 34a and the respective outer shell 35i, 35a are joined together flush in one of the flow directions.

(21) The plug-in connection between the inner shells 34i of the connected inner air gap insulated manifolds 31, 32 and the inner housing 29 forms a joining gap 52, which also produces a leakage. The width 53 of the joining gap 52 varies, for example, with the diameter of the inner housing 29 and is between 0.4 mm and 1.2 mm. As a result of this leakage, the crosstalk between the two inner housings 29 is made possible in this embodiment example as well. The respective inner air gap insulated manifold 31-32 is sealed with respect to the housing 2 by means of the connection of the outer shell 35i with the housing 2. The connection between the housing 2 and the outer shell of the respective air gap insulated manifold 31, 32 is preferably formed as a welded connection. Alternatively, a connection as a flange 7 or inlay 8 or V-band clamp 6 is provided according to FIGS. 5-7b.

(22) The inner and outer air gap insulated manifolds 30-33 shown in the embodiment examples are formed from sheet metal. Air gap insulated sheet metal manifolds demonstrate an advantageous resonance behavior. Due to the different shaping of the inner and the outer air gap insulated manifolds 30-33, the acoustic features are additionally improved at particular operating points of the internal combustion engine, because the vibration behavior and resonance behavior harmonize.

(23) 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 diameters 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 relevant rpm for the most important load regions, the distances A2, the diameter ratios De, Da and the identical shape of the corresponding openings of the air gap insulated manifolds 30-33 are thus relevant.