EP1122421A2 - Intake conduit with integrated exhaust gas recirculation - Google Patents

Abstract

The invention relates to an intake manifold with an integrated exhaust gas recirculation system (16, 17a, 17b). This is mainly located in the collecting space (12) of the suction pipe and is at a distance a from the walls (20) of the suction pipe. As a result, heat can be transferred to the housing of the suction pipe only to a small extent, so that this z. B. can be made of plastic. A further relief of the plastic housing, in particular the intake ducts (14), is achieved in that the intake air in the collecting space cools the exhaust gas in the exhaust pipes (17a, b), so that the intake air and exhaust gas mixture in the intake ducts (14) maintains the critical temperature for the exhaust gas recirculation rates does not exceed the plastic walls (20). <IMAGE>

Description

State of the art

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

Suction pipes of the type described in the introduction are known. How WO 97 / 34081 remove an intake pipe, through which the channels for exhaust gas recirculation Grooves are formed in the cylinder head flange, after the assembly of the Intake manifold on the cylinder head the missing wall of the exhaust gas recirculation channels be 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 from a temperature-resistant Material are made. For metal suction pipes, this condition is in the general uncritical. In the case of plastic suction pipes, which are extremely economical The thermal loads occurring can represent a solution exhaust gas recirculation, however, can lead to damage.

If you want to keep the thermal loads in the plastic suction pipe low, you get according to DE 198 19 123 A1 the possibility of exhaust gas recirculation in one To accommodate the intermediate flange, which is temperature-resistant and the cylinder head flange of the intake manifold connects to the cylinder head itself. Has this solution however, this results in a more complex structure of the intake tract. The savings in costs, which can be achieved by designing the suction pipe in plastic, are reduced by the additional effort of the intermediate flange.

The object of the invention is therefore a suction pipe with an integrated exhaust gas recirculation to create, in which the thermal from the exhaust gas recirculation The load on the intake manifold is low. This task is characterized by the characteristics of the Claim 1 solved.

Advantages of the invention

The suction pipe according to the invention has the known structure with inlet, collecting space, from this outgoing suction channels and outlets to the cylinders. The outlets can usefully be designed as a cylinder head flange. The Intake pipe can be used for a row arrangement, V arrangement or any other Arrangement of the cylinders can be provided. It is also possible to have multiple collection rooms to provide, which are assigned to the respective groups of suction channels.

Furthermore, the intake manifold has a connection for the exhaust gas recirculation. about An exhaust pipe leads the exhaust gas to supply openings, each of which is through the suction channels influenced flow area of the intake air are arranged. As a result, exhaust gas can be supplied separately to each cylinder, whereby a desired, ensures, in particular, uniform distribution of the exhaust gas over all cylinders becomes. Valves can be provided in the supply area of the exhaust gas, the one cylinder-selective exhaust gas introduction depending on the timing of the individual Allow cylinders. As the flow area influencing the suction channels understood the area of extensive assignment of the supplied exhaust gas to a suction channel. So below that is not just the volume of the suction channel to understand yourself. The feed openings can also be in the volume of Collecting space and in the vicinity of the suction openings formed by the suction channels, which open into the collecting room, can be arranged. This essentially means a clear assignment of the exhaust gas to the individual suction channels possible. Alternatively, however, is a stoichiometric distribution of openings in of the exhaust pipe possible, which achieve an even distribution of the exhaust gas in the intake air, which is then fed to the suction channels ..

In particular with several collecting rooms, several connections and Exhaust pipes are provided in the intake manifold. The connections and the exhaust pipe create a design advantage in the construction of the intake manifold Scope as there are fewer constraints when laying the cables in the collecting room by other components, such as. B. the injectors, cylinder head cover, generators, Pumps, the fuel rail or screwdriver clearances are observed have to. Another advantage is that the exhaust pipe through the intake air is flowed around in the collecting room. This way, before the exhaust gas is introduced cooling of the same is possible in the suction pipe. The cooling must, however not through a separate duct system or one that is foreign to the combustion air Cooling medium can be reached. An additional design effort for cooling is therefore not incurred. The requirements for the tightness of the exhaust duct are also lower in the intake manifold, since a small leak only leads to an earlier admixture of the exhaust gas leads to the intake air.

Compliance with a distance from the exhaust pipe to the walls of the intake manifold prevents heat conduction of the warming exhaust pipe into the intake pipe material. This can greatly reduce the thermal load on the intake manifold become. Direct heat conduction is only possible via the holding means, which fix the exhaust pipe inside the intake manifold. At least serves as a holding means a seal that is necessary at the edge of a bushing for the connection. The connection is therefore outside the intake manifold, so that a connection to the Exhaust system of the internal combustion engine is possible. Other holding means for the exhaust pipe can be achieved by all available means of connection technology.

Screw connections and rivets are conceivable, for example Clamping, plug-in and snap connections, in addition, with a multi-layer Structure of the intake manifold a fixation of the exhaust pipe by mounting the Intake pipe shells are made. Bridges as spacers can conduct heat minimize with sufficient fixation. A further minimization is advantageous possible in that the holding means themselves allow low heat conduction. This can be done in particular by a small cross section of the holding means, that create a thermal bridge between the intake manifold wall and the exhaust pipe, or by choosing materials with low thermal conductivity, e.g. B. ceramics.

According to a special embodiment of the invention can also be used as holding means the supply openings of the exhaust pipe serve if this through the walls of the Suction channels must be guided. A connection is therefore inevitable here between exhaust pipe and walls of the intake manifold, in particular the Suction channel, with the help 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 leading into the intake air in the intake ducts can be advantageous Design of the connection point in the bushings of the wall improved become. Here z. B. use a bellows-like pipe section, which for one by increasing the surface area of the bellows or extending the Wämemleitung stretch for thermal insulation of the exhaust pipe to the intake manifold leads there. The bellows-like piece of pipe itself is for passage or introduction of the exhaust gas in the suction channel. Furthermore, the bellows enables through its Elasticity a certain tolerance compensation between exhaust pipe and intake manifold. This becomes necessary on the one hand due to manufacturing tolerances that occur others because of the different thermal expansion of the materials the exhaust pipe and the intake manifold or their different thermal loads. Instead of the pipe section, a ceramic fitting can also be used be at least the thermal insulation between the exhaust pipe and Suction pipe guaranteed. The shaped piece made of ceramic can also be used for any Geometry of the discharge point, e.g. B. as a nozzle. The geometry of the discharge point can then with regard to an optimal distribution of the exhaust gas in the intake air be designed.

As already mentioned, the feed openings become in the area of the suction openings the suction channels arranged, so the heat transfer can be further reduced. In addition, there is a central introduction based on the cross section of the intake ducts possible, which ensures an even distribution of the exhaust gas in the intake air can be done. Large tolerances can also be realized.

A favorable design of the exhaust pipe results if it has multiple layers is trained. The shells can e.g. B. consist of two deep-drawn metal parts, with the help of complicated geometric structures of the exhaust pipe let it be realized. In addition, other functional components can be found in the shells be integrated. In particular flanges or spacers for fixing the exhaust pipe inside the intake manifold can be manufactured inexpensively. The through the The channel structure formed by the shells can be supplemented by other components, the the base part can be assembled. So it is z. B. possible by connecting Pipes to complete the exhaust pipe.

The manufacture of the exhaust pipe from a metallic material ensures good heat conduction from the exhaust gas to the intake air in the intake manifold. Thereby optimal cooling of the exhaust gas can be achieved up to the inlet points, which makes the walls of the intake manifold less thermal in the area of the inlet points be charged. In addition, metallic materials have a high temperature resistance, so that high recirculation rates of exhaust gas into the intake manifold are realized can be. At low thermal loads can be used for the exhaust pipe also a heat-resistant plastic, e.g. B. PPS can be used. Let it go favorable manufacturing and material costs are achieved.

The suction pipe itself is advantageously made of plastic. This is economical production possible. Especially with multi-shell technology the exhaust pipe without problems before final assembly of the intake manifold integrate. However, integration is also conceivable with plastic suction pipes, which are manufactured in melt core technology. In this case either Installation opening for the exhaust pipe are provided or the exhaust pipe in the Melting core are poured in, so that their position in the interior of the intake manifold is defined. Of course, the invention can also be used in suction pipes made of metal, e.g. B. aluminum.

The geometry of the exhaust pipe in the intake manifold can advantageously be made in this way design that the path covered by the exhaust gas from the respective connection to the respective feed opening to the suction channels is always the same length. This synchronizes the dead times between opening the exhaust gas recirculation valve and introduction of the exhaust gas into the suction channels. Besides, will In this way, the exhaust gas is cooled to the same extent as the individual inlet points reached. The equalization of these effects leads to an optimal one Pollutant reduction through exhaust gas recirculation. Furthermore, a possible Reduction of engine torque counteracted by a short circuit, caused by the exhaust gas recirculation lines, could arise. The length of the Lines counteracts this as a choke.

These and other features of preferred developments of the invention go not only from the claims but also from the description and the drawings, the individual features each individually or in groups in the form of sub-combinations in the embodiment of the invention and on others Areas to be realized and advantageous as well as protectable designs can represent, 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 using schematic exemplary embodiments. Show here

Figure 1

the partially sectioned view of an intake manifold for an internal combustion engine with a V-shaped cylinder arrangement in multi-shell technology, the cover shell being removed,

Figure 2

the section A - A according to Figure 1,

Figure 3

the section B - B according to Figure 1, two variants for the exhaust pipe are shown according to Figure 2 and

Figure 4 u. 5

Variants of the detail X according to FIG. 2,

Figure 6

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

Description of the embodiments

FIG. 1 provides an insight into a lower shell 10 of an intake pipe. It is to recognize how the intake air according to the arrows from an inlet 11 on two collecting spaces 12 reaches suction openings 13 of suction channels 14, which lead to Outlets of a cylinder head flange 15, not shown.

An exhaust pipe 17a, b leads from a connection 16, which is shown in FIG. 1 in two variants is shown, to supply openings 18a, b, which the introduction of the exhaust gas in Area of the suction channels allowed. The exhaust pipe 17a is by means of a snap connection 19 attached to walls 20 of the intake manifold. This creates a minimum distance a observed between wall 20 and exhaust pipe 17a, which leads to a thermal protection of the wall 20 contributes. The exhaust pipe 17b is by means of Screws 21 fastened via tabs 22 in the intake manifold.

The structure of the exhaust pipe 17b can also be seen in FIG. 2. This is composed of two shells 23, which creates the cavity for conduction the exhaust gases are created. The tab 22 for attaching the exhaust pipe is also integral part of one of the shells. The feed opening 18b is in a feedthrough 24b inserted in the wall 20b of the corresponding suction channel 14. On at this point there is an admixture to the intake air, which leads to one of the outlets 25 flows in the cylinder head flange 15.

The intake manifold is manufactured and welded using multi-shell technology. The suction channels 14 are welded into the lower shell 10. You also need a resonance flap 26 as a connection between the two collecting spaces 12 and the exhaust pipe 17b can be installed in the lower shell. Finally, an upper shell 27 with the lower shell 10 welded.

In Figure 3, the connection 16 is shown as a detail in section. The connection exists from a pipe socket 28 which with the aid of a mounting flange 29 in a Implementation 24 is fixed. A seal 30 in the form of an O-ring is in the Implementation housed. The tube ends in a screw socket on one side 31, which allows the attachment of an exhaust pipe 32 and on the other Side in the exhaust pipe 17a, b (both versions are shown). To conduct heat To keep the lower shell 10 as low as possible, the pipe socket is in the area the implementation 24 designed as a bell-shaped hollow profile 33.

However, the feed openings 18b in the bushings 24b can also be designed in this way be that the heat conduction from the exhaust pipe to the wall 20b of the Suction channels 14 is prevented. In Figure 4, the feed is designed as a piece of pipe 34, which contains a bellows 35. The exhaust pipe is on this piece of pipe 17b attached. The pipe section in turn is inserted into the bushing 24b. Instead of the pipe section, a shaped piece 36 made of ceramic can also be used. This is free in its design. A nozzle 37 is formed at the end thereof, which leads to a targeted introduction of the exhaust gas. This nozzle is corresponding the curvature of the suction channel 14 aligned in the flow direction of the intake air. As a result, the exhaust gas is immediately entrained and optimally in after the introduction of the intake air.

FIG. 6 shows another example of a suction pipe, a part of the Collection space 12 is cut open, so that 2 variants of an exhaust pipe 17c and 17d become visible. This is through connection 16 and the snap connection 19 fixed. The feed openings 18c of one variant open into the one described In the suction openings 13 of the suction channels 14. 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 it reaches the suction channels 14.

Claims (9)

Intake pipe with an integrated exhaust gas recirculation, containing at least one inlet (11) leading into a collecting space (12),
exhaust ducts (14) leading from the collecting space to cylinder-side outlets (25), one exhaust gas duct leading from a connection (16) to feed openings (18a, b, c), each of which is provided in the flow area of the intake air influenced by the suction ducts (14) ( 17a, b, c)
characterized in that the exhaust pipe (17a, b) is arranged in the cavities formed by the same and is fixed by holding means (19, 21, 28, 34, 36) while maintaining a distance to walls (20a, b) of the intake pipe, wherein as Holding means comprises at least one seal (30) of a passage (24) of the connection (16) through the walls (20a, b). Intake pipe according to claim 1, characterized in that the holding means (19, 21, 28, 34, 36) allow only a low heat conduction. Suction pipe according to claim 1 or 2, characterized in that holding means are provided which serve as a feed opening (18a, b, c) and are accommodated in passages (24b) in the walls (20b) forming the suction channels (14). Intake pipe according to claim 3, characterized in that the holding means consist of bellows-like pipe pieces (34) which allow the exhaust gas to be passed through and are inserted into the passages (24b) in the walls (20b) forming the suction channels (14). Intake pipe according to claim 3, characterized in that the holding means consist of ceramic shaped pieces (36) which allow the exhaust gas to pass through and are inserted into the passages (24b) in the walls (20b) forming the suction channels (14). Suction pipe according to one of claims 1 or 2, characterized in that the feed openings (18a, b) are arranged in the region of suction openings (13) of the suction channels (14) opening into the collecting space. Intake pipe according to one of the preceding claims, characterized in that the exhaust pipe (17a, b) is at least partially multi-shell, the cross section of the exhaust pipe being formed by the shells (23). Intake pipe according to one of the preceding claims, characterized in that the exhaust gas line (17a, b) is branched in such a way that the path to be covered by the exhaust gas from the at least one connection (16) to the feed openings (18a, b) is essentially of the same length . Intake pipe with an integrated exhaust gas recirculation, containing at least one inlet (11) leading into a collecting space (12),
Suction ducts (14) leading from the collecting space to cylinder-side outlets (25), one exhaust gas line (17d) leading from a connection (16) to feed openings (18d), each of which opens into the collecting space.
characterized in that the exhaust pipe (17d) is fixed in the collecting space of the suction pipe while maintaining a distance from the walls (20a, b) of the suction pipe and by means of holding means (19, 21, 28, 34, 36), at least one seal (30) being used as the holding means of a passage (24) of the connection (16) through the walls (20a, b) and that the feed openings (18d) are arranged in such a way that in the flow area of the intake air influenced by the suction channels (14) a homogeneous mixture with the exhaust gas with a essentially uniform concentration of the exhaust gas in the intake air is guaranteed.

Images