DE19757986A1 - Intake device for an internal combustion engine - Google Patents

Abstract

The invention relates to a suction device (11) for an internal combustion engine (12) which device is fitted with separate air intake means (14) for each cylinder, whereby in addition to the intake air exhaust gases can be fed to the suction device via exhaust-gas supply means provided separately for each cylinder. Because exhaust gas is supplied to each cylinder separately the quantity of exhaust gas supplied can be measured precisely and in particular be the same for each cylinder. In a preferred version of the invention the exhaust-gas supply means are situated in a connecting flange (15), which together with the air intake means (14) is mounted on the housing (13) of the engine (12) and has continuous air ducts (20). The exhaust-gas supply means are configured inside the connecting flange (15) as openings leading from a distribution chamber (23) collecting exhaust gas to the air ducts (20) or as exhaust-gas ducts (21) existing separately from the air ducts. The intake flange (15) which is heated by the exhaust gases is cooled sufficiently by being connected to the surface of the engine housing (13) and by the fact that intake air circulates through it.

Description

APPLICATION AREA AND PRIOR ART

The invention relates to a suction device for a Internal combustion engine with at least one combustion chamber and with separate air intake means for each combustion chamber, the intake device in addition to the intake air Exhaust gases from the engine can be supplied.

Intake devices have the purpose of being used in burning air that takes place in the combustion chamber, based mostly on an air filter, every combustion space, i.e. cylinder, to be fed individually. The feeder takes place in an inlet and from there via valves directly into the combustion chamber.

Due to environmental regulations, it is common or indispensable Lich, the intake air a certain proportion of Engine exhaust gases to be fed back, the recirculation rates are currently around 20% to 30%, with new direct splashes, however, should be up to 50%. With such large quantities encounter a variety of problems. On the one hand it is very important to evenly mix the gases to achieve the combustion processes in the Zylin  those who, today, use motor electronics down to the smallest detail Details are to be coordinated in the desired optimal Range and run the same for all cylinders. To this For example, DE 44 20 247 A1 or EP 0 369 482 suggest this a central introduction of the exhaust gases into an air intake manifold before that with the air intake and the throttle fold or feed connector is connected. Within this way the gases should mix, the gas flow then onto the individual cylinders is distributed.

WO 94/01673 proposes a similar solution, in which in an air inlet space, an air inlet, an opposite one Exhaust inlet and four air from the room suction pipes for the cylinders are attached. Most off all here however, there is a problem that is likely to be close to the air intake pipes arranged one contain a higher proportion of exhaust gas than that further away lying. The gas mixture is therefore not homogeneous and Combustion processes do not run in the desired optimum Range from which in turn disadvantageously increased exhaust emissions and drop in performance result.

An additional problem that is difficult to master lies in the combination of the air intake device, which consists of cost and production-technical reasons consists of plastic, with the exhaust gas supply and the usually quite high Exhaust gas temperatures and consequently the exhaust gas return guide tubes. The temperature of the exhaust gases is around 400 ° C to 450 ° C, thus occur at an insertion port at return rates from 20% to 30% at 120 ° C on the plastic suction device with target return rates of up to 50% even up to 200 ° C and more. This in turn exceeds Range of commonly used plastics, so that  either more expensive and more complex materials to process are to be used or complex devices, as in EP 0 369 482 and WO 94/01673 mentioned above are necessary become. Here either a tube made of a composite mat rial made of steel and aluminum with cooling fins as an intermediate piece proposed or a complex holder for an inlet socket made of aluminum, which is expected for long-term use is problematic.

TASK AND SOLUTION

It is therefore the object of the invention to provide an intake to create a direction for an internal combustion engine, the one in a desired area, as evenly as possible distributed exhaust gas supply to the intake air, which Temperature problems at high exhaust gas recirculation rates manageable power and is easy to manufacture and assemble.

This object is achieved in that each combustion chamber separate exhaust gas supply means are assigned. In this way it is possible to to achieve an optimal mixture composition. Another advantage is the mastery of high temperatures possible because the introduction of the exhaust gases into the air intake means is done separately and thus the the amount of exhaust gas flowing in at one point and thus the Temperature is reduced.

In a preferred embodiment, the exhaust gas supply means are in a connection device which can be connected to the internal combustion engine device, in particular a connecting flange between air intake means and internal combustion engine. An execution of the Device as a structural unit simplifies assembly, before a connecting flange is particularly suitable for this.  

Such a connection flange can be put together in one step mounted on the internal combustion engine with the air intake means be, for example, by the air intake means outgoing, preferably penetrating and attached to it attached, screws for fastening, which by the An closing device, in particular an edge area or molded eyelets, run and burn into the housing intervention motor.

In one embodiment of the invention, the exhaust gas supply medium in addition to the air intake in the combus tion motor or be guided to the combustion chamber, wherein the internal combustion engine preferably two per combustion chamber Gas flows can be supplied. A merge takes place here of the two gas flows only within the internal combustion engine or possibly shortly before entering the combustion space or so. So one is possibly desired spatially separable introduction possible.

In an alternative embodiment, the exhaust gas supply medium in the connection device with the air intake means be connected, the internal combustion engine or an inlet for the combustion chamber, preferably at least partially uniform mixture of the gas streams can be supplied. To this Not only is the amount of exhaust gas supplied per cylinder always the same, but it becomes a well swirled mixture fed. In this version there is also a rapid cooling extreme temperature of the exhaust gases or heating the possibly cold intake air possible. Furthermore is the Structure simplified.

A distribution chamber is preferred in the connection device for exhaust gases included with the exhaust system of burning voltage motor, in particular via at least one discharge point,  is connected, the connection preferably via a Pipe connection or the like. For an exhaust gas recirculation pipe. From from this distribution chamber, the individual exhaust gas supply go off to every combustion chamber. So continues a simple exhaust gas supply preferably via only exhaust gas recirculation pipe or the like possible, and from it a distribution to the individual exhaust gas supply means. The Distribution chamber can be designed differently, depending on For example, it can be used essentially as some kind of pipe or duct. The introduction of the Exhaust gases in the connection device or the distribution chamber can essentially be done at any point, depending according to the application and the problems that arise different.

The connecting device is advantageously at least partially as made of thermoplastic, in particular glass fiber reinforced polyamide, and can be injection molded be made. Depending on the design of the distribution chamber as well as the exhaust gas supply means can consist of a few parts or be made in one piece to reduce assembly effort ren. The connection device consists of several plastic share, for example by gluing, Ultra sound or vibration welding connected to one unit become. The choice of material mainly depends on the Recycle rate of the exhaust gases or of the temperatures that occur others. At temperatures above about 120 ° is different To use material, for example fiber-reinforced sulfurized polyphenylene, however, is also an embodiment made of aluminum or ceramic (for highest temperatures) Lich. The introduction can preferably be at one point take place on the direct cooling of the connecting flange through the built in the housing of the internal combustion engine Engine cooling is possible.  

In one embodiment of the invention, the exhaust gas supply means as breakthroughs from the distribution chamber into continuous air Channels executed, the breakthroughs preferably such are designed so that every combustion in the operation of the engine room or cylinder together with the intake air te, in particular the same amount of exhaust gas can be supplied. This represents a very simple method of exhaust gas introduction, above all, a variability of the breakthroughs of them Cross sections of an exhaust gas inlet into the distribution chamber Any place allows you to always get an even Distribution of the amount of exhaust gas to reach all cylinders. Due to the suction effect of the intake air flowing past, this becomes Exhaust gas sucked into the engine.

In an alternative embodiment of the invention, the Exhaust gas supply means each as abge from the distribution chamber Exhaust gas channels to be executed, the additional, preferred wisely separated and / or parallel to the continuous air Lead the channel into the internal combustion engine. In this version mixing of the two gas streams takes place only after and outside the connector. The opposite of the previous execution somewhat increased effort for production can be compensated for by the fact that others or improved Suction principles can be used. For example it is possible that one channel at least partially the other encloses, in particular the air channel within the Exhaust duct runs, preferably as a pipe that with the Connection device connected holding or stored therein is. Such a suction ent through a kind of annular gap speaking of the Venturi effect enables the suction of particularly large amounts of exhaust gases. The one another enclosing the channels allows an effective Cooling, especially in a version in which the air duct  has direct contact with the connecting device and the Exhaust duct surrounds.

Due to the preferably flat attachment to the at least partially cooled motor housing also becomes the connector flange from the high exhaust gas temperature to one less critical and approved for the selected material Temperature possible. The outside of the connector can be equipped with an enlarged surface to a release of heat to the ambient air and thus cooling to effect.

These and other features go beyond the claims also from the description and the drawings, wherein the individual features individually or separately several in the form of sub-combinations in one execution tion form of the invention and realized in other fields his and advantageous as well as protectable execution can represent conditions for which protection is claimed here. The division of the application into individual sections as well Subheadings limit those made under them Statements are not generally applicable.

BRIEF DESCRIPTION OF THE DRAWINGS

Two embodiments of the invention are in the drawings are shown schematically and are described in more detail below explained. The drawings show:

Fig. 1 is a side view of a suction device according to the invention, which is connected as a connecting flange between the air intake pipes and the motor housing with the motor,

Fig. 2 shows a longitudinal section through the suction device of Fig. 1 in the central plane, with breakthroughs connecting a distribution chamber with air channels and

Fig. 3 shows a section in a central plane in a variant of a Ansaugvor direction according to the invention, in which air ducts and exhaust ducts enclose each other.

DESCRIPTION OF TWO PREFERRED EXAMPLES

Fig. 1 shows a suction device 11 for a combus- tion engine 12 , which has certain air intake means 14 for connection to the motor housing 13 and a connecting flange 15 as a connecting device.

The air intake means 14 have at the end of the curved out air intake pipes 16 on a molded flange 17 , by means of which they are placed against the flat flange 15 , being screwed to the engine 12 by means of penetrating through both parts and reaching into the motor housing 13 screws 19 will. Dashed lines run through both the flange 17 and the connection flange 15, an air channel 20 which merges into an inlet 22 shown in dash-dotted lines in the motor housing 13 , which in turn leads to a combustion chamber or cylinder, not shown. Perpendicular to the image plane extends in the right area of the connecting flange 15 a distribution chamber 23, each of which has apertures 24 as Abgaszuführmittel for each air channel 20 of a cylinder. The through these breakthroughs 24 in the air channels 20 from the distribution chamber 23 exhaust gas is the connecting flange 15 and the distribution chamber 23 through a pipe connection 25 which is connected to an inlet point 26 with the intake flange 15 , respectively. At this designed as a short pipe socket pipe connection 25 , an exhaust gas recirculation pipe, not shown, which goes from the exhaust system of the engine 12 , can be connected in any practical way.

Between the flange 17 of the air intake pipes 16 , the connecting flange 15 and the housing 13 of the motor 12 , seals can be provided, for example from temperature-resistant or the like, for sealing the connections to one another. At its other end, the air intake pipes 16 are connected to a central air intake 18 , preferably an air filter (not shown).

The connecting flange 15 is carried out in Fig. 1 so that the distribution chamber 23 runs near a motor cooling line 28 ver, sometimes even (as shown) in parallel. In this way, an effective cooling of the connecting flange 15 in the region of its greatest temperature load is possible.

The section through a central plane of the connecting flange 15 in FIG. 2 illustrates the schematic configuration of a connecting flange according to FIG. 1. The connecting flange has an essentially rectangular, elongated shape, with air channels passing through it and perpendicular to the image plane 4 20 run with a circular cross section. Via openings 24 , which can be designed as a kind of bore perpendicular to the air channels 20 , they are connected to the distribution chamber 23 which extends in the longitudinal direction of the intake flange 15 . Approximately in the middle between the air channels 20 is provided on a longitudinal side of the pipe connection 25 , in Fig. 2 a piece is formed, to which an exhaust gas recirculation pipe, not shown, is ruled out. It forms the inlet point 26 for exhaust gases into the distribution chamber 23 . The pipe connection 25 preferably has a circular cylindrical shape, with a flange at the end for fastening the exhaust gas recirculation pipe. Through the connection flange 15 each have holes 29 in the corner area through which the screws 19 are guided.

The cross-section of the openings 24 , as shown in a greatly exaggerated manner in FIG. 2, differs, the two openings arranged closer to the pipe connection each having a smaller cross-section than the two outer or more distant ones. Here, the exhaust gas pressure is different due to the proximity to the inlet point, the closer the cross-section is.

Fig. 3 shows an alternative embodiment of a connection flange according to the invention, wherein both the pipe connection 25 arranged differently and the exhaust gas supply means are no longer designed as simple openings 24 . The introduction of the exhaust gases into the distribution chamber 23 takes place via a pipe connection 25 arranged on one end face, which runs from the introduction point 26 in the opposite direction to the elongated distribution chamber 23 . In contrast to the arrangement in FIG. 2, a strongly uneven supply of the exhaust gases to the individual exhaust gas supply means, which, as shown, is compensated for by the different shape of the cross sections of the openings 24 to exhaust gas channels 21 . Similar to FIG. 2, the different design of the cross section of the openings 24 is shown here in a greatly exaggerated manner.

The openings 24 lead to exhaust gas channels 21 , which are formed either inside the air channels 20 or outside, at least partially surrounding them. The far left of the air duct is formed as a cylindrical continuous tube, is spaced by means of thin holding webs 31 of the inner wall of the connecting flange 15 and the exhaust duct 21 is supported on the connecting flange. These holding webs 31 do not run continuously between the air duct and the exhaust duct, so that a distribution of the exhaust gases in the exhaust duct 21 around the air duct is possible.

The exhaust gas supply means to the right are formed as a central exhaust duct 21 , at least partially circularly, which is surrounded by an air duct 20 with an annular cross-section which is not completely continuous in the circumferential direction. The exhaust duct 21 is guided here within the air duct 20 .

To the right of this again, an embodiment is shown in which the exhaust gas duct 21 with an approximately circular cross section largely encloses the approximately tubular air duct 20 , the tube of the air duct 20 being connected to the connecting flange 15 by means of a holding web 31 is. Here, the exhaust gas supply means largely surround the air duct 20 , which makes it possible, for example, to preheat the intake air.

In the three previously described exemplary embodiments of the exhaust gas supply means, both the air and exhaust gas channels, in particular as pipe sections, are formed by the connecting flange 15 . The design of the exhaust gas supply means on the far right, on the other hand, represents an exhaust gas channel 21 , which is designed similarly to the air channels 20 in FIG . Within this runs an air duct 20 , the outer diameter of which is at a certain distance from the wall of the exhaust duct 21 , and as an extension of an air intake pipe 16 of the air intake means 14 is formed. As a result, it does not require a holder within the connecting flange 15 .

All of the exhaust gas supply means described in FIG. 3 are designed according to the annular gap principle, as a result of which particularly effective suction of the exhaust gases by the intake air into the engine 12 takes place. The openings 24 are formed from left to right on the pipe connection 25 with a decreasing cross section, since there is the greatest exhaust gas pressure. The attachment is also in Fig. 3 via screws 19 , not shown, either through flange 15 in the corner area of the connecting screw holes 29 or, as shown at the lower right corner, for example, by means of fastening eyes 32 formed.

In the drawings, only one-piece pipe connections 25 are shown with the connecting flanges 15 . However, composite variants are also possible, in particular made of different materials, in order to meet the respective requirements for the components.

FUNCTION

Depending on the design of the connecting flange 15 , it can be produced in one piece, for example by injection molding from a thermoplastic material, for which purpose, however, a relatively complex injection mold is required (a variant according to FIG. 3 is better suited for this). Preferably, the connecting flange 15 is composed of two half shells but with an approximately the sectional plane in Fig. 2 and Fig. 3 corresponding to the plane of separation. These two shells can either be connected to each other before installing the connecting flange, for example by releasable connection such as screwing or riveting, or an inseparable connection such as gluing or welding (e.g. ultrasonic or vibration welding). Likewise, assembly of the two individual sections similar to that in FIG. 1 is possible, since the screwing by means of the screws 19 with the combustion engine 12 both parts are pressed together in a durable and sealing manner on their joining surface. Furthermore, it is possible to integrate (inject) a shell into the suction pipe in a two-part solution made of plastic and only to mount, preferably weld, the second shell.

The pipe connection 25 can either be integrally formed as shown in FIGS . 2 and 3, or can be used subsequently in the connecting flange 15 . If retrofitted, there is the possibility of manufacturing the pipe connection 25 from a different material, for example aluminum or other metal that tolerates high exhaust gas temperatures, or alternatively industrial ceramics.

Depending on the version, the connection flange 15 is placed above the inlets 22 for the cylinders to mount the suction device 11 on the motor 12 , and then the air suction medium 14 is screwed to the motor housing 13 with its flange 17 and the screws 19 . In a manner not shown, an exhaust gas recirculation pipe is connected to the pipe connection 25 .

During operation of the engine 12 , air is sucked in, namely through the central air intake 18 , the air flow being distributed from there to a number of air intake pipes 16 , which corresponds to the number of cylinders, and from there through the air channels 20 of the connecting flange 15 is sucked into the inlets 22 . As it passes through the connecting flange 15, the intake air draws exhaust gases from the distribution chamber 23 into the inlet 22 either through the openings 24 or the exhaust gas channels 21 . Depending on the position of the inlet point 26 and the geometry of the distribution chamber 23, the cross section of the openings 24 or the exhaust gas channels 21 is designed (differently) in such a way that the same amount of air is present in each air channel, which is essentially the same Exhaust gas is supplied to the cylinder.

An inlet cross-section is preferred which is the same for all openings 24 , in which case the distributor chamber can be made approximately conical so that the same amount of exhaust gas can be supplied to each cylinder. The distributor chamber expands advantageously from the introduction point 26 to the most distant breakthrough.

Due to the relatively large cross section of the distribution chamber 23 in relation to the sum of the cross sections of the openings 24 , the exhaust gas flow is the hottest in the region of the openings 24 , the material of the connecting flange 15 being cooled at the same time by the intake air flowing through the air channels 20 . This cooling effect through the air channels 20 can be used in a similarly positive manner in an embodiment according to FIG. 3. A cross-sectional geometry of the air channels 20 is also conceivable, which has a very large contact area with the housing of the connecting flange 15 compared to the cross-sectional area. In this way, an improved cooling of the connection flange can take place with a constant flow of air.

The design of the connecting flange 15 or the connecting device is variable within wide limits, especially to save material can be deviated from the outer cuboid shape shown in FIGS . 1 to 3 Darge in that, for example, between the air channels 20 or the screw holes 29th Recesses or incisions in the material are provided. The weight can also be reduced in this way. A device according to the invention can be used for any internal combustion engine, regardless of the number of cylinders.

Claims (10)

1. Intake device for an internal combustion engine ( 12 ) with at least one combustion chamber and with separate air intake means ( 14 ) for each combustion chamber, the intake device ( 11 ) in addition to the intake air exhaust gases from the engine can be supplied, characterized in that each combustion chamber separate exhaust gas supply means assigned. 2. Intake device according to claim 1, characterized in that the exhaust gas supply means in a combustible engine ( 12 ) connectable connecting device, in particular a special connecting flange ( 15 ) between air intake means ( 14 ) and internal combustion engine are included. 3. Intake device according to claim 1 or 2, characterized in that the exhaust gas supply means in addition to the air intake means ( 14 ) in the internal combustion engine ( 12 ) are guided, the combustion engine per combus tion space preferably two gas flows can be supplied. 4. Intake device according to claim 2, characterized in that the exhaust gas supply means are connected to the air intake means ( 14 ) in the connecting device, the internal combustion engine ( 12 ) preferably being able to be supplied with an at least partially uniform mixture of the gas streams. 5. Intake device according to one of the preceding claims, characterized in that in the connecting device a distribution chamber ( 23 ) for exhaust gases is contained, which is connected to the exhaust system of the internal combustion engine ( 12 ), in particular via at least one inlet point ( 26 ) , preferably via a Rohran circuit ( 25 ) for an exhaust gas recirculation pipe, the exhaust gas supply means coming from the distribution chamber. 6. Suction device according to one of claims 2 to 5, characterized in that preferably in the spray Casting device manufactured at least consists partly of plastic, in particular glass fiber reinforced polyamide, being preferred is in one piece. 7. Suction device according to claim 5 or 6, characterized in that the exhaust gas supply means are designed as openings ( 24 ) from the distribution chamber ( 23 ) in continuous air channels ( 20 ), the openings being preferably designed such that the operation of the Motor ( 12 ) a certain, in particular the same, amount of exhaust gas can be supplied to each combustion chamber together with the intake air. 8. Suction device according to claim 5 or 6, characterized in that the exhaust gas supply means are each designed as from the distribution chamber ( 23 ) outgoing exhaust gas channels ( 21 ) which are additionally, preferably separately and / or parallel, to the continuous air channel ( 20 ) into the internal combustion engine ( 12 ). 9. Intake device according to claim 8, characterized in that one channel at least partially surrounds the other, in particular the air channel ( 20 ) within the exhaust channel ( 21 ), preferably as a tube which is connected to the connection device holding . 10. Suction device according to claim 2, characterized in that from the air suction means ( 14 ) outgoing, preferably abutting, screws ( 19 ) for attachment through the connecting device, in particular through screw holes ( 29 ) in a Randbe rich or molded attachment eyes ( 32nd ), and engage in the housing ( 13 ) of the internal combustion engine ( 12 ).