EP1122421B1 - Intake conduit with integrated exhaust gas recirculation - Google Patents

Abstract

An intake manifold with an integrated exhaust gas recirculation system (16, 17a, 17b) which is located primarily within a plenum (12) of the intake manifold and is spaced at a distance (a) from the walls (20) of the intake manifold. This limits the heat transfer to the housing of the intake manifold, so that the housing may be manufactured, for example, of synthetic resin material. Further relief of the synthetic resin housing, particularly of the intake channels (14), from thermal stress is provided in that the intake air within the plenum cools the exhaust gas in the exhaust lines (17a, b), so that the intake-air/exhaust-gas mixture within the intake channels (14) does not exceed the critical temperature for the. synthetic resin walls (20) of the channels even if the exhaust gas recirculation rates are high.

Description

State of the art

The invention relates to a suction pipe with an integrated exhaust gas recirculation, which has a connection for the exhaust gas and supply openings for the various suction channels, according to the preamble of claim 1.

Suction tubes of the type described above are known, for example. From the JP 409317579 A or the JP 410131813A , That's how it works WO 97/33081 remove a Saurohr in which the channels for exhaust gas recirculation are formed by grooves in Zylinderkopfflansch, wherein after installation of the intake manifold on the cylinder head the missing wall of the exhaust gas recirculation channels are formed by this.

Due to the thermal loads occurring in the exhaust gas recirculation channels at least the cylinder head flange of the intake manifold must be made of a temperature-resistant material. With metal intake pipes, this condition is generally not critical. In plastic suction pipes, which represent a decidedly economical solution, however, the occurring thermal stresses in the exhaust gas recirculation can lead to damage.

If you want to keep the thermal loads in Kunststoffsaugrohr low, it follows according to the DE 198 19 123 A1 the ability to accommodate the exhaust gas recirculation in an intermediate flange, which is temperature resistant and connects the cylinder head flange of the intake manifold with the cylinder head itself. However, this solution has a more complex structure of the intake system result. The cost savings that can be achieved by the execution of the suction tube in plastic are reduced by the additional cost of the intermediate flange.

The object of the invention is therefore to provide a suction pipe with an integrated exhaust gas recirculation, in which the outgoing of the exhaust gas recirculation thermal load of the intake manifold is low. This object is solved by the features of claim 1.

Advantages of the invention

The intake manifold according to the invention has the known structure with inlet, plenum, from this outgoing suction channels and outlets to the cylinders. The outlets can be meaningfully designed as a cylinder head flange. The suction tube may be provided for a series arrangement, V-arrangement or any other arrangement of the cylinder. It is also possible to provide a plurality of collecting chambers, which are assigned to respective groups of suction channels.

Furthermore, the intake manifold has a connection for the exhaust gas recirculation. Via an exhaust pipe, the exhaust gas is guided to supply ports, which are each arranged in the influenced by the suction channels flow region of the intake air. As a result, each cylinder separately exhaust gas can be supplied, whereby a desired, in particular uniform distribution of the exhaust gas is ensured on all cylinders. In the feed region of the exhaust gas, valves can be provided which enable a cylinder-selective exhaust gas introduction depending on the timing of the individual cylinders. The flow region influencing the intake passages is understood to mean the region which largely corresponds to the supplied exhaust gas allows for a suction channel. This not only means the volume of the suction channel itself. The supply openings may also be arranged in the volume of the collecting space and in the vicinity of the suction openings formed by the suction channels, which open into the collecting space. As a result, an unambiguous assignment of the exhaust gas to the individual suction channels is essentially possible. Alternatively, however, a stoichiometric distribution of openings in the exhaust pipe möglich.Diese achieve a uniform distribution of the exhaust gas in the intake air, which is then fed to the suction channels.

In particular, in the case of several collecting chambers, it is also possible to provide a plurality of connections and exhaust gas pipes in the intake manifold. The connections and the exhaust pipe create in the construction of the suction advantageously a creative scope, as when laying the lines in the plenum less boundary conditions by other components such. As the injectors, Zyinderkopfhaube, generators, pumps, the fuel rail or screwdriver release must be observed. Another advantage is that the exhaust pipe is flowed around by the intake air in the plenum. In this way, before the introduction of the exhaust gas into the suction pipe, a cooling of the same possible. However, the cooling does not have to be achieved by means of a separate duct system or a cooling medium which is alien to the combustion air. An additional design effort for the cooling is therefore not applicable. Also, the requirements for the tightness of the exhaust passage in the intake manifold are lower, since a low leakage only leads to an earlier admixing of the exhaust gas to the intake air.

The maintenance of a distance of the exhaust pipe to the walls of the intake manifold prevents heat conduction of the heating exhaust pipe in the Saugrohrmaterial. As a result, a thermal load on the intake manifold can be greatly reduced. A direct heat conduction is possible only via the holding means which fix the exhaust pipe in the intake manifold inside. As a holding means is at least one seal, which is necessary at the edge of a passage for the connection. The connection is thus outside the intake manifold, so that a connection to the exhaust system of the internal combustion engine is possible. Further holding means for the exhaust pipe can be achieved by all available means of connection technology.

There are, for example, fittings and rivets conceivable, continue clamping, plug and snap connections, also can be done in a multi-shell construction of the suction pipe fixation of the exhaust pipe by mounting the intake manifolds. Bars as spacers can minimize the heat conduction at a sufficient fixation. A further minimization is advantageously possible because the holding means themselves allow a low heat conduction. This can be achieved in particular by a small cross section of the holding means, which produce a thermal bridge between Saugrohrwandung and exhaust pipe, in addition to the choice of ceramic as a material with low thermal conductivity, as claimed in claim 1.

According to a particular embodiment of the invention may serve as holding means and the supply openings of the exhaust pipe, if they must be passed through the walls of the suction channels. This inevitably results in a connection between the exhaust pipe and the walls of the intake manifold, in particular of the suction channel, by means of which the exhaust pipe can be fixed.

Such an arrangement of the feed opening, which leads to a defined introduction of the exhaust gas into the intake air in the suction channels, can be improved by an advantageous embodiment of the connection point in the passages of the wall. Here can be z. B. use a bellows pipe section, which leads to a by the enlargement of the surface on the bellows or an extension of the Wämemleitungsstrecke to a thermal insulation of the exhaust pipe to the intake manifold. The bellows-like pipe section itself is suitable for the passage or introduction of the exhaust gas into the suction channel. Furthermore, the bellows allows by its elasticity a certain tolerance compensation between exhaust pipe and intake manifold. This is necessary on the one hand due to manufacturing tolerances, on the other hand, but also due to the different thermal expansion of the materials of the exhaust pipe and the intake manifold or their different thermal load. Instead of the pipe section and a ceramic fitting can be used, which ensures at least the thermal insulation between the exhaust pipe and intake manifold. With the ceramic fitting can also be any geometry of the discharge, z. B. as a nozzle reach. The geometry of the discharge point can then be designed in terms of an optimal distribution of the exhaust gas in the intake air.

If, as already mentioned, the feed openings are arranged in the region of the suction openings of the suction channels, the heat transfer can be further reduced. In addition, a central introduction based on the cross section of the intake ports is possible, whereby a uniform distribution of the exhaust gas can be carried out in the intake air. In addition, large tolerances can be realized.

A favorable embodiment of the exhaust pipe results when this is formed mehrschalig. The shells can z. B. consist of two deep-drawn metal parts, can be realized with the help of complicated geometric structures of the exhaust pipe. In addition, further functional components can be integrated in the shells. In particular, flanges or spacers for fixing the exhaust pipe in the intake manifold inside can be produced inexpensively. The channel structure formed by the shells can be supplemented by other components that can be mounted to the base. So it is z. B. possible to complete the connection of pipes exhaust pipe.

The production of the exhaust pipe made of a metallic material ensures good heat conduction from the exhaust gas to the intake air in the intake manifold. As a result, an optimal cooling of the exhaust gas can be achieved up to the discharge points, whereby the walls of the suction pipe in the region of the discharge points are less thermally stressed. In addition, metallic materials have a high temperature resistance, so that high return rates of exhaust gas can be realized in the intake manifold. At low thermal load can also be a heat-resistant plastic, eg. As PPS used. In this case, favorable manufacturing and material costs can be achieved.

The suction pipe itself is advantageously made of plastic. As a result, an economical production is possible. Especially in multi-shell technology, the exhaust pipe before the final assembly of the intake manifold can be easily integrated into this. However, integration is also conceivable for plastic suction pipes, which are manufactured in melt core technology. In this case, either an installation opening for the exhaust pipe would have to be provided or the exhaust pipe to be poured into the melting core, thereby defining their position in the intake manifold inside. Of course, the invention can also in suction pipes made of metal, for. As aluminum, apply.

Advantageously, the geometry of the exhaust pipe in the intake manifold can be designed such that the distance traveled by the exhaust gas path from the respective port to the respective supply port to the suction channels is always the same length. As a result, the dead times are synchronized, which arise between the opening of the exhaust gas recirculation valve and the introduction of the exhaust gas into the suction channels. In addition, an equally strong cooling of the exhaust gas is achieved up to the individual discharge points in this way. The homogenization of these effects leads to an optimal emission reduction by exhaust gas recirculation. Furthermore, a possible reduction of the engine torque is counteracted, which could be caused by a short circuit caused by the exhaust gas recirculation lines. The length of the lines counteracts the throttle.

These and other features of preferred embodiments of the invention will become apparent from the claims and from the description and drawings, wherein the individual features are each realized alone or in the form of sub-combinations in the embodiment of the invention and in other fields and can represent advantageous and protectable versions for which protection is claimed here.

drawing

Figur 1

die teilweise geschnitten dargestellte Aufsicht auf ein Saugrohr für eine Brennkraftmaschine mit V-förmiger Zylinderanordnung in Mehrschalentechnik, wobei die Deckelschale abgenommen ist,

Figur 2

den Schnitt A - A gemäß Figur 1,

Figur 3

den Schnitt B - B gemäß Figur 1, wobei entsprechend Figur 2 zwei Varianten für die Abgasleitung dargestellt sind und

Figur 4 u. 5

Varianten des Details X gemäß Figur 2,

Figur 6

zwei Varianten für eine im Sammelraum eines aufgeschnitten dargestellten Saugrohres eingebaute Abgasrückführleitung.

Further details of the invention are described in the drawings with reference to schematic embodiments. Show here

FIG. 1

the partially cut plan view of a suction pipe for an internal combustion engine with a V-shaped cylinder arrangement in multi-shell technology, wherein the cover shell is removed,

FIG. 2

the section A - A according to FIG. 1 .

FIG. 3

the section B - B according to FIG. 1 , where appropriate FIG. 2 two variants for the exhaust pipe are shown and

Figure 4 u. 5

Variants of the detail X according to FIG. 2 .

FIG. 6

two variants for an exhaust gas recirculation pipe installed in the collecting chamber of a suction pipe cut open.

Description of the embodiments

The FIG. 1 provides an insight into a lower shell 10 of an intake manifold. It can be seen how the intake air ensprechend the arrows from an inlet 11 via two plenums 12 to suction 13 of suction channels 14 passes, leading to not shown outlets of a Zylinderkopfflansches 15.

From a connection 16 leads an exhaust pipe 17 a, b, in FIG. 1 is shown in two variants, to supply ports 18a, b, which allows the introduction of the exhaust gas in the region of the suction channels. The exhaust pipe 17a is attached by means of a snap connection 19 to walls 20 of the suction pipe. As a result, a minimum distance a between the wall 20 and the exhaust pipe 17 a is maintained, which leads to a thermal protection of the wall 20 contributes. The exhaust pipe 17b is fastened by means of screws 21 via tabs 22 in the intake manifold.

The structure of the exhaust pipe 17b may continue the FIG. 2 be removed. This is composed of two shells 23, whereby the cavity for the passage of the exhaust gases is formed. The tab 22 for securing the exhaust pipe is also an integral part of one of the shells. The feed opening 18b is inserted into a passage 24b in the wall 20b of the corresponding suction channel 14. At this point, an addition to the intake air, which flows to one of the outlets 25 in the cylinder head flange 15.

The suction tube is manufactured in multi-shell technology and welded. The suction channels 14 are welded into the lower shell 10. Furthermore, a resonance flap 26 must be installed as a connection between the two collecting chambers 12 and the exhaust pipe 17b in the lower shell. Finally, an upper shell 27 is welded to the lower shell 10.

In FIG. 3 the connection 16 is shown as a detail in section. The connection consists of a pipe socket 28 which is fixed by means of a mounting flange 29 in a bushing 24. A seal 30 in the form of an O-ring is housed in the bushing. The tube opens on one side into a screw socket 31, which allows the attachment of an exhaust gas supply line 32 and on the other side in the exhaust pipe 17a, b (both versions are shown). In order to keep a heat conduction in the lower shell 10 as low as possible, the pipe socket in the region of the bushing 24 is designed as a bell-shaped hollow profile 33.

But also the feed openings 18b in the passages 24b may be configured such that the heat conduction from the exhaust pipe to the wall 20b of the suction channels 14 is prevented. In FIG. 4 the supply is designed as a pipe section 34 which contains a metal bellows 35. On this pipe section, the exhaust pipe 17b is attached. The pipe piece in turn is inserted into the passage 24b. According to claim 1, a molding 36 made of ceramic will be used. This is free in its design. At the end of which a nozzle 37 is formed, which leads to a targeted introduction of the exhaust gas. This nozzle is aligned according to the curvature of the suction channel 14 in the flow direction of the intake air. As a result, the exhaust gas is entrained immediately after the introduction and optimally distributed in the intake air.

In FIG. 6 shows another example of a suction pipe, wherein a part of the collecting space 12 is cut open, so that 2 variants of an exhaust pipe 17c and 17d are visible. This is fixed by the connection 16 and the snap connection 19. The feed openings 18c of the one variants open into the suction openings 13 of the suction channels 14 in the manner described. The feed openings 18d are distributed stoichiometrically or regularly on the surface of the exhaust pipe 17d and thus lead to a uniform mixing of the intake air with recirculated exhaust gas, before this the suction channels 14th reached.

Claims (5)

1. Intake pipe with an integrated exhaust gas recirculation, comprising at least one intake (11) leading into a collecting chamber (12), with intake ports (14) leading from the collecting chamber to cylinder-sided outlets (25), with an exhaust gas pipe (17a, b, c) leading from a connection (16) to supply openings (18a, b, c) which are provided each in the flow area of the intake air affected by the intake ports (14), characterized in that the exhaust gas pipe (17a, b), by observing a certain distance to the walls (20a, b) of the intake pipe, is disposed in the hollow space formed by the intake pipe and fixed by means of fasteners (19, 21, 28, 34, 36), the fasteners comprising at least one sealing (30) of a passage (24) of the connection (16) through the walls (20a, b) and the fasteners comprising ceramic fittings (36) which allow the exhaust gas to be conveyed and which are inserted into the passages (24b) realized in the walls (20b) forming the intake ports (14).
2. Intake pipe according to claim 3, characterized in that the fasteners comprise bellows type tube sections (34) which allow the exhaust gas to be conveyed and which are inserted into the passages (24b) realized in the walls (20b) forming the intake ports (14).
3. Intake pipe according to one of the claims 1 or 2, characterized in that the supply openings (18a, b) are disposed in the area of the intake openings (13) of the intake ports (14) leading into the collecting chamber.
4. Intake pipe according to one of the above claims, characterized in that the exhaust gas pipe (17a, b) is at least partially made in a multiple shell design, the cross section of the exhaust gas pipe being shaped by the shells (23).
5. Intake pipe according to one of the above claims, characterized in that the exhaust gas pipe (17a, b) is branched in such a way that the distance to be covered by the exhaust gas from the at least one connection (16) to the supply openings (18a, b) is substantially of the same length.

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