MXPA00002701A - System for recirculating exhaust gas in an internal combustion engine - Google Patents

Abstract

The invention relates to a system for recirculating exhaust gas in an internal combustion engine. A connecting line (4;10, 13;26) for the recirculated exhaust gas is connected to an intake pipe (2;15;22), cooling elements being arranged in between. The cooling element may be e.g., a cooling channel (5;18;19;25) for liquid coolant, integrated into the flange-type connection joining the connecting line (4;10, 13;26) to the intake pipe (2;15;22), or may be another heat conductive element.

Description

SYSTEM TO RECIRCULATE EXHAUST GAS IN AN ENGINE OF INTERNAL COMBUSTION The present invention relates to an arrangement for recirculating exhaust gas in an internal combustion engine, in which an interconnection conduit for the exhaust gas to be recirculated is connected with interconnection of cooling elements to a suction pipe. In an arrangement of this type known from DE 30 34 971 C3, exhaust gases are supplied from the internal combustion engine, which come from the exhaust gas pipe, to the suction channel for the internal combustion engine. The interconnection tube is incorporated to a considerable extent in a heat exchanger in order to cool the exhaust gas to be fed back. It is also known that the exhaust gas pipe to be refilled is fixed by means of a flange through two screws in the suction pipe made of plastic. In order to achieve a thermal decoupling of the exhaust gas pipe from the suction pipe, a mixing air is supplied in the flange region by means of a diffuser tube for the purpose of cooling. With this arrangement it is possible to reduce the temperature of the exhaust gas in the flange area from about 450 ° C to about 125 ° C with a feedback ratio of about 20%. The temperature peaks are present in such arrangements, especially in the areas of the sealing gaskets which are generally made of plastic, in the connection of the interconnection duct for the exhaust gas to be recirculated and in the areas opposite to each other. with respect to the exhaust gas inlet opening. In this case it is often difficult to remove sufficient heat due to the relatively small cross sections and the relatively long paths. In many cases of application in connection with direct injection engines, selective feeding of the exhaust gas per cylinder is also frequently required, which causes additional thermal problems due to the possible feedback ratios of the exhaust gases (up to 50%). The present invention has the purpose of developing an arrangement of the initially mentioned type, which allows an optimum decrease in temperature. The inventive arrangement is particularly advantageously suited to satisfy the purpose proposed by the fact that the cooling element is constituted by a cooling channel for cooling fluid, said cooling channel being integrated in a connection arrangement in the form of a flange of the conduit of interconnection in the suction tube. Due to the fact that a cooling element in the form of a refrigerant pipeline for cooling fluid, which is integrated in the flange-type connection arrangement of the interconnecting conduit, is applied in the interconnection conduit for the exhaust gas to be recirculated. Suction tube, it is possible to reduce the thermal stresses of the suction tube constituted of plastic with simple means, also in the case of higher recirculation ratios of exhaust gas. This measure can also positively influence the temperature of the air drawn in through the suction tube. Overall, the thermal stresses of the internal combustion engine, the exhaust gas temperature, the NOx emission and the fuel consumption are reduced with the inventive arrangement. If the cooling liquid intended for cooling the motor is used as a cooling liquid, a simple and inexpensive construction is also obtained. The cooling channel can be integrated in a particularly advantageous manner in the suction pipe, which is generally constituted by plastic, the passage of the cooling channel being to the internal combustion engine disposed in the cylinder cover flange of the engine., the interface being sealed with an additional sealing gasket. Alternatively, it is also possible to arrange an independent cooling duct in the flange between the exhaust gas pipe and the suction pipe, or alternatively that the cooling duct is arranged in a predetermined length in or on the exhaust pipe. , if necessary, that the cooling duct is integrated into the exhaust gas pipe. According to another embodiment of the present invention, the cooling element is constituted by a thermally conductive massive piece, which is a component part of the interconnecting conduit and is applied in the area of the flange-type connection of the suction pipe. in the cylinder cover. By means of the massive connection, by way of example, of a distributor tube for exhaust gas to be recirculated, in the cylinder cover, it is possible to simply cool the gases through the flange of the cylinder Limpet, which presents all Cooling channels modes. In a particularly advantageous manner, it is also possible to make use at least partially of the fastening elements of the suction tube in the cylinder cover as fastening elements for the bulk part. It is also possible in a particularly advantageous manner to provide a cooling duct, through which the cooling fluid circulates, in the area of the application of the massive part on the cylinder cover or at least partially in the massive part, with which can be further optimized the cooling performance. In another embodiment, the thermally conductive bulk piece is constituted by a tubular insert, which is internally integrated in the suction pipe. Said insert is seated with a front face under thermal contact against the cylinder cover. With this arrangement, a good heat transmission between the insert, which preferably consists of metal, and the cylinder cover can be ensured in a simple manner by mounting the suction tube on the cylinder cover. By means of this heat transfer, the thermal energy supplied by the exhaust gas can be diverted to the cooled cylinder cover. This heat transfer can be increased if necessary also by the fact that the front face of the insert, which is seated against the cylinder cover, has an increased diameter. A tubular interconnecting passage for the recirculated exhaust gas is coupled outwardly by the side wall of the insert, so that the interconnecting passage passes through the wall of the suction tube. The interconnecting duct and the insert are mutually connected in a sealed manner, and it is not necessary to provide additional seals between the interconnecting conduit and the suction pipe. The incoming exhaust gas consequently strikes against the inner wall of the cooled insert and therefore does not cause increased thermal stress on the plastic of the suction pipe. Particularly advantageous results when a recess in the suction tube is provided in the transfer zone of the interconnection tube, so as to form a free radial separation with respect to the interconnection tube and consequently avoid in this zone an eventual thermal stressing of the tube. of aspiration. These and other features of preferred developments of the present invention arise, in addition to the claims, also from the specification and the drawings, the different characteristics being able to be realized in each case by themselves or several in the form of subordinate combinations in the form of carrying out the present invention and in other fields, representing advantageous embodiments that are protectable by themselves for which protection is claimed. Drawings Exemplary embodiments of an inventive arrangement for the cooling of recirculated exhaust gas in an internal combustion engine in connection with the accompanying drawings will now be described., in which: Figure 1 illustrates a view in principle of a cylinder cover of the combustion engine with a connection arrangement, cooled by means of a cooling fluid, for the exhaust gas to be recirculated towards the suction pipe. Figure 2 illustrates a cut through the connection flange for the recirculated exhaust gas, with a cooling duct. Figure 3 illustrates a view in principle of a distributor tube for the exhaust gas to be recirculated, with a massive connection in the cylinder cover. Figure 4 illustrates a cut through the arrangement through Figure 3.

Figure 5 illustrates a detailed drawing of a modified embodiment of the arrangement according to figures 3 and 4. Figure 6 illustrates a section through an embodiment with an insert in contact with the hot gases. Figure 7 illustrates a detailed view of a modified embodiment of the arrangement according to figure 6. Description of the embodiment examples Figure 1 shows a cylinder cover 1 of an internal combustion engine with the essential parts for the understanding of the present case. On a suction pipe 2, through which the air is fed to the respective combustion chambers of the internal combustion engine, a connection arrangement 3 is provided for an interconnection conduit 4 through which exhaust gas is recirculated. of the exhaust gas duct towards the suction pipe 2. The exhaust gas flowing through the interconnection duct 4 has a correspondingly high temperature due to the combustion in the engine, which may eventually deteriorate the suction pipe and the exhaust pipes. Adjacent accessories, since they are designed for normal air temperatures and built largely of plastic. A cooling duct 5 is connected to the connection flange 2 for the recirculated exhaust gas, through which flows according to the arrows 6a (inlet) and 6b (outlet) the cooling fluid that is nevertheless required for the engine . In figure 2, according to another view, the configuration of this cooling duct 5 extending around the connection flange 2 and consequently around the interconnection pipe 4 for the recirculated exhaust gas is illustrated. The outline of the flange according to FIG. 2 is fixed by means of two screws 7 in the suction pipe 2 made of plastic material. In the center of this flange contour, the interconnecting conduit 4 is inserted. An exemplary embodiment is shown in FIG. 3, in which a distributor tube 10 provided for the exhaust gas to be recirculated is provided, which is arranged on a block of cylinders 11. In figure 4 this arrangement is illustrated in section. The recirculated exhaust gas flows through the free cross section 12 of the distributor tube 10 and is in each case diverted through respective pipes 13 and corresponding connection flanges 14 towards a suction pipe 15. For fixing this distributor pipe In the cylinder cover 11, it is possible to use preferentially available screws 16, possibly via a metal sleeve 17 provided for fixing the respective suction tube 15. In the cylinder block 11 there is provided according to FIG. cooling 18, through which the cooling liquid flows. According to an exemplary embodiment according to FIG. 5, a cooling channel 19 can also be integrated at least partially into the distributor pipe 10, in this case additional sealing gaskets 20 being necessary. An exemplary embodiment is shown in FIG. , which has a metallic insert 21, which is mounted on the suction tube 22 made of plastic so that a front end 23 of said insert is seated on the cylinder cover 24 in order to ensure its thermal conductivity. A cooling duct 25 is also provided in the cylinder cover 24. In the insert 21 a connecting pipe 26 for the gas to be recirculated is rigidly mounted laterally and tightly. With respect to the plastic material of the suction tube 22 surrounding the connecting tube 26, a light or gap 27 is provided in this case to prevent the relatively high temperatures of the connecting tube 26 from damaging the plastic of the suction tube 22. The recirculated exhaust gas flows according to the arrows 28 inside the insert 21, which is relatively cold and bounces off its internal jacket, so that the thermal stresses of the plastic of the suction pipe are not so high. To further improve the cooling of the insert 21, the contact area of the front end 23 of the insert has been increased according to FIG. 7, thereby achieving an improved thermal contact between the insert 21 and the cylinder cover 24.

Claims (13)

1. Claims 1) Arrangement for recirculating exhaust gas in an internal combustion engine, in which an interconnection conduit for the exhaust gas to be recirculated is connected with interconnection of cooling elements to a suction pipe, characterized in that the element of Cooling is constituted by a cooling channel for cooling fluid, said cooling channel being integrated in a connection arrangement in the form of a flange of the interconnecting passage in the suction tube.
2. 2) Arrangement according to claim 1, characterized in that the cooling fluid provided for the cooling of the motor is used as cooling fluid.
3. 3) Arrangement according to claim 1 or 2, characterized in that the cooling duct is integrated in the suction pipe made of plastic, the passage of the cooling duct being to the internal combustion engine located in the cylinder cover flange of the cylinder. motor and said step being sealed at the interface with an additional seal.
4. 4) Arrangement according to claim 3, characterized in that an independent refrigerant pipe is arranged between the exhaust gas pipe and the suction pipe.
5. 5) Arrangement according to at least one of claims 1 to 4, characterized in that the cooling duct is arranged in a predetermined length also in or on the exhaust gas pipe.
6. 6) Arrangement according to claim 5, characterized in that the cooling duct is integrated in the exhaust gas pipe.
7. 7) Arrangement for recirculating exhaust gas in an internal combustion engine, in which an interconnection conduit for the exhaust gas to be recirculated is connected with interconnection of cooling elements to a suction pipe, characterized in that the cooling element is constituted by a thermally conductive massive piece, which at least partly constitutes a component part of the interconnection conduit and which is applied in the cylinder cover in the area of the connection in the form of a flange of the suction pipe.
8. 8) Arrangement according to claim 7, characterized in that as fixing element for said massive part, use is made at least partially of those fixing elements used for fixing the suction tube in the cylinder cover.
9. 9) Arrangement according to claims 7 or 8, characterized in that the distributor tube provided for the distribution of the recirculated exhaust gas to multiple cylinders is integrated in said massive piece.
10. 10) Arrangement according to at least one of claims 7 to 9, characterized in that a cooling duct, through which the cooling fluid circulates, extends in the region of the fixing of said massive part inside the cylinder cover or also partially in said cylinder cover and in said massive piece.
11. 11) Arrangement according to claim 7, characterized in that the thermally conductive bulk piece is constituted by a tubular insert mounted on the suction pipe, said insert having a front face under thermal contact against the cylinder cover, and having been laterally coupled in the I insert the interconnection duct in the form of a tube through the wall of the suction tube.
12. 12) Arrangement according to claim 11, characterized in that a recess in the suction tube is provided in the area of passage of the tube-shaped interconnection duct so as to form a free radial separation with respect to said interconnecting duct in the form of a tube. of tube.
13. 13) Arrangement according to claim 11 or 12, characterized in that the front face of the insert, which sits against the cylinder cover, has an increased area by increasing the outer diameter of said insert.