EP2333265B1 - Exhaust manifold with guide plate - Google Patents

Abstract

The manifold (1) has an upper shell (3) and a lower shell (4) that are welded completely with an engine flange (2), where the manifold is manufactured as a thin-walled metal sheet component. A guiding plate (5) is inserted into the manifold at a cylinder head-side and provided for separating an inner area (6) of the manifold from the engine flange. The guiding plate has openings that extend into an area of exhaust duct openings of the engine flange. The guiding plate is connected fixedly with the upper and lower shells by using thermal joints.

Description

The present invention relates to an exhaust manifold for mounting by means of a motor flange on a cylinder head of an internal combustion engine having at least two cylinders in series, wherein the exhaust manifold is made as a thin-walled sheet metal component in shell construction with an upper shell and a lower shell.

In multi-cylinder internal combustion engines, the exhaust of each cylinder is combined in exhaust manifolds.

Exhaust manifolds can be made in a known manner from cast steel or built from individually welded together steel sheets or pipe fittings. The advantage of Stahlgusskrümmern is that complicated geometries are relatively inexpensive to produce. The weight of cast steel elbows, however, is generally higher than that of welded sheet steel constructions. Also, cast steel manifolds have higher thermal inertia than welded exhaust manifolds.

Welded exhaust manifolds can only be produced with increased complexity and thus higher costs in complex geometries. However, they have a lower heat capacity due to their lower weight. That's an advantage.

A further development of the built exhaust manifolds are the air gap insulated exhaust manifold. In air gap insulated exhaust manifolds, the exhaust gas ducts are surrounded by a supporting outer shell while maintaining a defined air gap. The outer shell is usually gas-tight welded with connection flanges. However, air gap insulated exhaust manifolds have the disadvantage that their construction is more expensive.

Due to the desire to increase the efficiency of internal combustion engines, the engines are often charged by a compressor, usually a turbocharger. An increase in the efficiency of the turbocharger has an effect on the increase in efficiency of the internal combustion engine.

It is advantageous if the charging of the engine takes place quickly, which is only possible if the turbocharger starts quickly and the unwanted turbo lag fails. However, this requires certain flow cross sections, so that the gas pulse of the exhausted combustion gases from the engine is not attenuated in the exhaust manifold. It is therefore possible to choose as possible cross sections, which are not too large in cross section; so that the impulse acts as directly as possible on the blades of the turbocharger or even unfolds its desired effect in a pressure wave supercharger. If, therefore, a highly contoured cross-sectional geometry of the exhaust-carrying ducts or the exhaust manifold is desired, this generally leads to a relatively complex design of the exhaust manifold. Exactly this, however, is problematic in built, ie not produced in the original molding process exhaust manifolds, since the sheet metal components are becoming more complex and also create manufacturing problems due to a complicated weld seam management, which may adversely affect product quality and, above all, adversely affect product price.

For example, is from the EP 1 172 534 A2 an exhaust manifold is known in which an upper shell and a lower shell are welded to a motor flange. Such exhaust manifold is inexpensive to produce, but exposed to a direct thermal distortion due to the hot exhaust gas. In addition, the only small shaping possibilities do not result in a direct possibility of influencing the pressure pulses present in the exhaust manifold.

Object of the present invention is therefore to provide an exhaust manifold, which allows a low heat capacity and cost manufacturability and an increase in efficiency of the internal combustion engine.

This object is achieved with an exhaust manifold according to the features of patent claim 1.

Advantageous developments of the present invention are the subject of the dependent claims 2 to 12 ..

It is envisaged that the exhaust manifold has a motor flange by means of which it is attached to a cylinder head of an internal combustion engine having at least two cylinders in series. The exhaust manifold should be made as a thin-walled sheet metal component in shell construction with an upper shell and a lower shell. Such an exhaust manifold is inventively characterized in that in the exhaust manifold on the cylinder side, in particular a one-piece baffle is used, which separates the interior of the exhaust manifold from the engine flange.

Due to the separation of the motor flange from the interior of the exhaust manifold, the heat input into the solid motor flange is reduced. The engine flange is usually designed as a cast steel product, which gives the exhaust manifold a high thermal inertia. The mass of the Motor flange is not readily reducible because it has a supporting function for the exhaust assembly and also subject to high thermal stresses. Therefore, the invention is the way to separate the flange area by area of the interior of the exhaust manifold. However, this does not take place in that the sheet metal shells of the exhaust manifold only partially, namely only in the region of the exhaust port openings, are connected to the motor flange, but rather that a baffle inside the exhaust manifold takes over the task of shielding. This has the advantage that the exhaust manifold or the upper and lower shells of the exhaust manifold can be completely welded to the engine flange with a much simpler weld seam guide. The upper and lower shell of the exhaust manifold are less complex. The simplified geometry enables simpler tools and thus a more cost-effective production of sheet metal components. In particular, however, the welding of the upper and lower shells with the motor flange is easier, since the exhaust manifold is designed as a hood and must take no account of the shield of the exhaust manifold from the engine flange, as this function belongs to the baffle. Depending on the design of the baffle is influenced by the course of the flow path of the exhaust gas within the exhaust manifold, which in turn has a positive effect on the light-off behavior of a downstream turbocharger, which increases the overall efficiency of the internal combustion engine. The construction of thin-walled sheet metal components leads to a low heat capacity and thus to a low heat dissipation, so that a downstream catalyst faster the necessary. Operating temperature reached and thus emission limits can be better met.

In a first development, only the surfaces of the motor flange facing the interior of the exhaust manifold are covered by a baffle. As a result, the heat energy contained in the exhaust gas is only partially possible, a heat input in the. To perform motor flange. It is within the scope of the invention quite possible to provide a plurality of individual baffles, each between the individual outlet duct openings of the Motor flange are arranged and are tuned individually to the prevailing in the region of these outlet channel openings flow conditions.

Particularly preferably, the guide plate has openings in the region of outlet channel openings of the motor flange. The exhaust gas thus enters the exhaust manifold through the exhaust ports of the cylinder head and through the exhaust port openings of the engine flange. The outlet channel openings in the baffle make it clear that the baffle extends around the openings. In an exhaust manifold with, for example, four exhaust duct openings, the baffle may accordingly also have four openings, so that in total only one single baffle has to be produced, which is position-oriented or fixed on the sheet metal shells of the exhaust manifold or on the motor flange. Of course, it is within the scope of the invention, however, also possible to provide a plurality of Einzelelleitbleche with corresponding openings for the Auslasskanalöffnungen the motor flange. Several of these baffles can be joined to form an assembly prior to installation in the exhaust manifold. However, it is considered most convenient if the number of components for making an exhaust manifold is minimal and thus only a single appropriately configured baffle is used.

In a further embodiment variant, the guide plate has a collar in the region of its openings, which extend into the outlet channel openings. A resulting advantage is that the exhaust gas flow is already separated from the engine flange in the exhaust port opening. The outflowing exhaust gas is thus already thermally isolated from the engine flange when exiting the exhaust duct of the cylinder head. Thus, the thermal inertia decreases in the entire exhaust manifold, which is advantageous with increasing emission requirements for internal combustion engines noticeable. Especially in the cold start behavior, the response of Abgasperipheriegeräten, such. B. a NOx-Kat or a diesel particulate filter shortened by a rapid heating.

Preferably, sliding seats are formed between the collar and the outlet channel openings of the motor flange. The baffle consists of a thin-walled sheet metal component, whereas the motor flange of a thick-walled cast material. consists. The baffle is exposed directly to the hot exhaust gas flow, whereas the engine flange is exposed to ambient temperature. Especially in cold start behavior or even at full load operation, the different thermal expansion of the materials and types is noticeable. Any distortions that arise through different thermal expansions are compensated by a sliding seat, so that a better durability of the baffle is given.

In a particularly preferred embodiment, the guide plate is at least partially spaced from the motor flange in a region between the openings. This offers on the one hand the advantage that in the space spaced a cavity is formed, which thermally isolates the motor flange from the baffle. The cavity may also be filled with exhaust gas, which, however, due to the gas inertia has a lower temperature and possibly a lower pressure ratio than the exhaust gas in the interior of the exhaust manifold. Even if the cavity is filled with exhaust gas, this does not mean that the engine flange is not separated from the interior of the baffle. Separated according to the invention does not necessarily mean a hermetic, in particular gas-tight shielding, which can only be realized with a particularly careful connection of the baffle with the upper shell and the lower shell. Rather, a shield is sought in the sense that the vast majority of the exhaust gas does not come into contact with the engine flange solely by the flow velocity and flow direction, which by pressure equalization between the interior of the exhaust manifold and the cavities separated therefrom, which also within the exhaust manifold There is a slight gas exchange, but essentially does not go beyond the said pressure equalization. The advantages of the invention are thus achieved even if the guide plate is not gas-tight with the upper shell and the lower shell of the Exhaust manifold is connected, although a substantial gas tightness is sought.

Another advantage resulting from the cavities is that the interior of the exhaust manifold is reduced in volume. Particularly with regard to the response of the turbine wheel of a turbocharger, a small volume of the interior of the exhaust manifold is advantageous. An escaping gas shock from a cylinder in the form of an exhaust stroke is thus forwarded as directly as possible to the turbine blades. A reduction of the flow velocity due to an increasing volume of the exhaust manifold is thereby counteracted.

In this case, areas of the guide plate between the openings are preferably formed arcuate. The volume of the interior of the exhaust manifold is purposefully reduced by the arc shape with respect to the exhaust passage. An arcuate geometry in the context of the invention is to be understood as a geometry shape in which the greatest distance to the motor flange is located centrally between the two outlet channel openings and the distance to the outlet channel openings is reduced so that there is contact with the outlet openings at the end. For example, a triangular, trapezoidal or other shape is conceivable under an arcuate design. However, for fluidic reasons, gentle transitions are preferred, so that the arc is actually a circular arc or an elliptical section or has another shape composed of curved sections.

Depending on the application, the shape must be optimally adapted to the internal combustion engine. In this case, for example, the exhaust back pressure in the exhaust system is to be observed. Another influencing factor in the choice of the shape of the spacing of the guide plate from the engine flange between the outlet channel openings is, for example, the arrangement of a further flange for connecting an exhaust pipe or two flanges or an exhaust gas recirculation. The arcuate area must therefore be identical in any case between all adjacent outlet openings. The arcuate areas can be completely different from each other in their concrete embodiment. Decisive is their function to shield the engine flange and keep the exhaust or the heat input to form a cavity away from the motor flange while adjusting the flow cross sections.

In a further preferred embodiment, the baffle is located on the upper shell and the lower shell circumferentially in a contact area. Due to the circumferential concern of the engine flange of the interior of the exhaust manifold, which is formed by upper, lower shell and baffle separated. The contact area can be formed both non-gas-tight and gas-tight.

Particularly preferably, the contact area is formed parallel to a respectively corresponding surface of the upper and lower shell. In particular, a substantially peripheral flanged edge is formed in the contact region, wherein the direction of the flare facing the engine flange or pointing away from the engine flange is formed. The crimping edge increases the rigidity of the baffle against the high pressures occurring in the exhaust manifold interior. Furthermore, the bead gives the entire exhaust manifold a higher rigidity against pressure and vibration, which affects the durability of the exhaust manifold. It is also possible in the course of the invention to attach a sealing compound to the peripheral flanged edge, so that the guide plate in the contact area is circumferentially sealed gas-tight.

Preferably, the baffle in the contact area is at least partially fixedly connected to the upper shell and the lower shell, wherein the compound is particularly preferably made by means of material connection. In order to produce a good durability, for example, a connection by thermal joining is feasible. Thermal joining offers the advantage that the exhaust manifold can be produced cost-effectively, but it also guarantees a particularly high durability. The durability is important because different temperature dependent Extensions of the individual structural components occur. The thermal strains cause stresses, especially in the area of welds. Due to the vibration loads occurring in the exhaust area, it must absolutely be ensured that no components come loose, which, in addition to a functional impairment, could also lead to disturbing rattling noises.

Further advantages, features, characteristics and aspects of the present invention will become apparent from the following description, preferred embodiments with reference to the schematic drawings. These are for easy understanding of the invention.

Figur 1

eine perspektivische Schnittdarstellung eines erfindungsgemäßen Abgaskrümmers;

Figur 2

einen Längsschnitt in einer Draufsicht eines Abgaskrümmers und

Figur 3

eine perspektivische Ansicht eines erfindungsgemäßen Leitblechs.

Show it:

FIG. 1

a perspective sectional view of an exhaust manifold according to the invention;

FIG. 2

a longitudinal section in a plan view of an exhaust manifold and

FIG. 3

a perspective view of a baffle according to the invention.

In the figures, the same reference numerals are used for the same or similar parts, with corresponding or comparable advantages being achieved, even if a repeated description is omitted for reasons of simplicity.

FIG. 1 1 shows a perspective sectional view of an exhaust manifold 1 comprising a motor flange 2, an upper shell 3 and a lower shell 4.
A baffle 5 is inserted into the interior 6 of the exhaust manifold 1 thus formed. The guide plate 5 separates the interior 6 of the exhaust manifold 1 from surfaces 7 of the motor flange 2.

FIG. 2 shows a longitudinal section in a plan view of an exhaust manifold 1 according to the invention. The baffle 5 in this case has openings 8, which extend into outlet channel openings 9 of the motor flange 2. The openings 8 of the baffle 5 have to collar 10.

The baffle 5 separates in areas between the openings 8, the surfaces 7 of the motor flange 2 from the interior 6 of the exhaust manifold 1. The areas 11 between the openings 8 are preferably formed arcuate. In an embodiment variant shown here, the central arcuate region on the image plane has a greater extent into the interior 6 than the arcuate regions lying on the edge. The respective outer arcuate region can also be made flatter because the housing of the exhaust manifold 1 has a smaller cross section in its end regions than in its central region where the outlet flange 14 is located, to which the collected exhaust gas is supplied.

In FIG. 1 In addition, a flange 15 of an exhaust gas recirculation can be seen. The exhaust flange 14 and the flange 15 for exhaust gas recirculation are in this embodiment at an angle to each other, wherein the flange 15 is disposed in the transition region of the upper shell 3 to the lower shell 4. The outlet flange 14 is located in the region of the lower shell 4 in this exemplary embodiment.

To represent the FIG. 1 It should also be noted that there are two recesses 16 in the area of the upper shell 3. These recesses serve to fix the baffle 5, namely by welding in the region of the recesses 16. The welding takes place with flanged edges 13 of the baffle 5. The flanged edges 13 belong to a contact area 12 which runs parallel to the corresponding surfaces of the upper and lower shell 3, 4. Out FIG. 1 It can be seen that the upper and lower shell 3, 4 are not flat at their opposite outer sides, but have beads 17, which are necessary for mounting technical reasons for screwing the engine flange 2 to an internal combustion engine, not shown. When looking into the interior of the exhaust manifold 1 it can be seen that the flanged edge 13 is adapted in its course to the beads as well as to the remaining inner contour of the upper and lower shell 3, 4 in order to produce the highest possible gas tightness. The recesses 16 are located between the beads. These welds effectively form the fixed bearing of the baffle 5, which thereby under Training a sliding seat in the individual outlet channel openings 9 of the motor flange 2 protrudes.

Out FIG. 3 It is clear that the flanged edge 13 is not only present in the arcuately curved region, but also surrounds the collar 10. As a result, the guide plate 5 also in the region of its openings 8 increased rigidity.

Reference numerals:

1 -

exhaust manifold

2 -

motor flange

3 -

Upper shell

4 -

subshell

5 -

baffle

6 -

inner space

7 -

Areas to 2.

8th -

openings

9 -

Outlet channel openings to 2.

10 -

collar

11 -

Area to 5.

12 -

plant area

13 -

flanging

14 -

outlet flange

15 -

flange

16 -

recess

17 -

Beading

Claims (12)

1. An exhaust manifold (1) for fitting by means of an engine flange (2) to a cylinder head of an internal combustion engine having at least two in-line cylinders, wherein the exhaust manifold (1) is manufactured as a thin-walled sheet-metal component in a shell design having an upper shell (3) and a lower shell (4), with the upper shell (3) and the lower shell (4) being fully welded to the engine flange, characterised in that a baffle plate (5) which separates an interior space (6) of the exhaust manifold (1) from the engine flange (2) is set into the exhaust manifold (1) on the cylinder head side.
2. An exhaust manifold according to Claim 1, characterised in that the faces (7) of the engine flange (2) which face the interior space (6) are covered by the baffle plate (5).
3. An exhaust manifold according to Claim 1 or 2, characterised in that the baffle plate (5) exhibits openings (8) in the region of exhaust channel openings (9) of the engine flange (2).
4. An exhaust manifold according to any one of Claims 1 to 3, characterised in that the baffle plate (5) exhibits in the region of its openings (8) collars (10) which extend into the exhaust channel openings (9).
5. An exhaust manifold according to Claim 4, characterised in that sliding seats are configured between the collars (10) and the exhaust channel openings (9) of the engine flange (2).
6. An exhaust manifold according to any one of Claims 3 to 5, characterised in that, in a region (11) between the openings (8), the baffle plate (5) is at least in part at a distance from the engine flange (2).
7. An exhaust manifold according to Claim 6, characterised in that the region (11) between the openings (8) is arched in configuration.
8. An exhaust manifold according to any one of Claims 1 to 7, characterised in that the baffle plate (5) lies peripherally in a contact region (12) against the upper shell (3) and the lower shell (4).
9. An exhaust manifold according to Claim 8, characterised in that the contact region (12) is configured in parallel with a respectively matching face of the upper shell (3) and of the lower shell (4).
10. An exhaust manifold according to Claim 8 or 9, characterised in that the contact region (12) is configured as an essentially peripheral flanged edge (13) wherein the direction of the flanging is configured pointing towards the engine flange (2) or pointing away from the engine flange (2).
11. An exhaust manifold according to any one of Claims 8 to 10, characterised in that in the contact region (12) the baffle plate (5) is firmly connected at least in sections with the upper shell (3) and the lower shell (4).
12. An exhaust manifold according to Claim 11, characterised in that the connection is effected by way of material bonding, preferably thermal joining.

Images