FR3049981A1 - INTERNAL COMBUSTION ENGINE COMPRISING AN INTEGRATED EXHAUST GAS REDIRECTION DRIVE AT THE CYLINDER HEAD - Google Patents

Abstract

The invention relates primarily to an internal combustion engine comprising: - a cylinder head (41), - an exhaust gas redirection pipe (40) able to redirect a part of the exhaust gases coming from a collector of exhaust (20) to an inlet (51) of said internal combustion engine, characterized in that said redirection pipe (40) is integrated with said cylinder head (41) and connected to said exhaust manifold (20) via a quill (43). ) made in a wall of said exhaust manifold (20).

Description

INTERNAL COMBUSTION ENGINE COMPRISING AN INTEGRATED EXHAUST GAS REDIRECTION DRIVE AT THE CYLINDER HEAD

The present invention relates to an internal combustion engine having an exhaust pipe redirection integrated in the cylinder head. The invention finds a particularly advantageous, but not exclusive, application in the field of motor vehicles.

In an internal combustion engine, the four stages of the thermodynamic cycle - admission of fuel gas and air, compression of the gas mixture, expansion due to the explosion of the mixture, exhaust - take place successively in the enclosures of the cylinders engine, said combustion chambers. The gases introduced into these combustion chambers consist on the one hand of air and on the other hand of gasoline or gas oil, in proportions proportionally dosed according to the engines and ignition systems used. The gas mixture is then ignited in the combustion chamber.

[0003] The exhaust gases of internal combustion engines fitted to most motor vehicles contain a certain number of pollutants which it is desirable to reduce the discharges into the atmosphere (in particular nitrogen oxides, carbon monoxide, unburned hydrocarbons, particulates and carbon dioxide). The regulations applicable to pollution by motor vehicles regularly lower the limits of acceptable discharges.

A large part of the pollutants generated by an internal combustion engine is due to incomplete combustion of the fuel. To reduce the discharge of pollutants entering the exhaust line, it is known to use an EGR system (acronym for "Exhaust Gas Recirculation") for recirculating a portion of the exhaust gas to the exhaust pipe. admission of the internal combustion engine.

For this purpose, the EGR system comprises an exhaust gas redirection pipe adapted to redirect a portion of the exhaust gas from the exhaust manifold to the engine inlet after passing through a heat exchanger.

An EGR valve is used to manage the amount of exhaust gas re-injected at the intake.

Such an architecture is however cumbersome because of the presence of the redirection duct bypassing the cylinder head. In addition, since the temperature of the combustion gases at the outlet of the exhaust manifold is high (between 850 and 1050 degrees), it is necessary to use auxiliary devices to cool the exhaust gases before entering the EGR valve. which is limited in thermal resistance.

The invention aims to overcome these disadvantages by providing an internal combustion engine comprising: - a cylinder head, - an exhaust gas redirection pipe adapted to redirect a portion of the exhaust gas from a collector exhaust system to an intake of the internal combustion engine, characterized in that the redirection pipe is integrated with the cylinder head and connected to the exhaust manifold via a nozzle in a wall of the exhaust manifold.

The invention thus allows, thanks to the integration of the redirection pipe in the cylinder head, to increase the compactness of the engine. This facilitates the implementation of other features including to minimize the emission of polluting particles from the engine.

In one embodiment, the redirection pipe extends between two water cores. The invention thus allows a thermal gain since the gases from the exhaust manifold are cooled by the water cores. The EGR valve can then operate at temperatures less thermally constraining.

In one embodiment, the water cores respectively correspond to an upper water core and a lower water core of the cylinder head.

In one embodiment, the exhaust manifold is integrated with the cylinder head.

According to one embodiment, an output of the redirection pipe is in communication with a valve, called the EGR valve, adapted to manage a quantity of exhaust gas passing through a heat exchanger which is in communication with a distributor of heat. admission of the internal combustion engine.

According to one embodiment, the internal combustion engine comprises an attached support attached to the cylinder head and for receiving the EGR valve.

According to one embodiment, the support comprises a first fixing interface to allow attachment of the support on the cylinder head so that an inlet opening of the valve is positioned in front of an outlet end of the pipe. redirection.

According to one embodiment, the support comprises a second fixing interface to allow attachment of the heat exchanger on the support so that an outlet opening of the valve is positioned in front of an inlet of the heat exchanger.

The invention also relates to a motor vehicle comprising an internal combustion engine as previously defined.

The invention will be better understood from reading the following description and examining the figures that accompany it. These figures are given for illustrative but not limiting of the invention.

[0018] Figure 1 is a schematic representation of an internal combustion engine architecture equipped with an exhaust gas recirculation system according to the present invention; Figure 2 is a perspective view of the exhaust gas recirculation system provided with its EGR valve and an exchanger in communication with the intake distributor; Figures 3 and 4 are respectively top views and a detailed perspective of a cylinder head according to the invention incorporating the exhaust gas redirection pipe; Figure 5 is a sectional view of the cylinder head according to the invention illustrating the positioning of the redirect pipe between an upper water core and a lower water core of the cylinder head; Figure 6 is a perspective view illustrating the attachment of the support of the EGR valve which is connected to the exchanger of the EGR system according to the invention.

Identical elements, similar, or the like retain the same reference from one figure to another.

[0024] Figure 1 shows an architecture 1 comprising an internal combustion engine 5 supercharged by a turbocharger 2 comprising a compressor 3 and a turbine 4. The compressor 3 compresses the intake air to optimize the filling of engine cylinders 5. For this purpose, the compressor 3 is disposed on an intake pipe 8 upstream of the engine 5. The flow of the exhaust gas drives in rotation the turbine 4 disposed on an exhaust pipe 9, which then rotates the compressor 3 via a coupling shaft. A turbocharger control valve 2 located upstream of the turbine 4 makes it possible to manage the quantity of exhaust gas flowing through the turbine 4 and the quantity of gas passing through a discharge pipe 16.

In order to maintain the density of the air acquired at the outlet of the compressor 3, a heat exchanger 10 called RAS (for cooling air cooler) is used to cool the air flowing in the duct. intake 8. The exchanger 10 is mounted downstream of the compressor 3 and upstream of an air metering device 18.

The internal combustion engine 5 comprises a cylinder head 41 covering a cylinder block and a cylinder head gasket mounted between these two elements (not shown). The cylinder block and the cylinder head 41 are typically made of an aluminum alloy. As shown in Figures 2 and 3, the yoke 41 has housing 26 for mounting sets candle / injector. For each cylinder, the cylinder head 41 has two passages 27 of intake valves and two other passages 28 of exhaust valves. In addition, the yoke 41 also comprises a cooling circuit traversed by a cooling liquid, for example water containing antifreeze.

Furthermore, a system 23 for recirculating exhaust gas (called "EGR" for "Exhaust Gas Recirculation" in English) comprises a redirection pipe 40 of the exhaust gas adapted to redirect a portion of the exhaust gases. exhaust from an exhaust manifold 20 to the inlet 51 of the engine 5 after passing through an exchanger 14.

Thus, a portion of the exhaust gas of the engine 5 is rejected to the outside of the motor vehicle through the exhaust pipe 9 and another part of the gas is recycled. The quantity of gas to be recirculated is controlled by the EGR valve 25 mounted between the outlet of the redirection pipe 40 and the heat exchanger 14 which is in communication with the inlet manifold 45 clearly visible in FIG.

The redirection pipe 40 is integrated with the yoke 41 and connected to the exhaust manifold 20 via a stitching 43 clearly visible in Figure 4 formed in a wall of the exhaust manifold 20. By "integrated" is meant the The redirection duct 40 is in this case molded with the cylinder head 41 but could alternatively be machined in the cylinder head 41. The exhaust manifold 20 is also integrated. at the breech 41 being preferably molded with the breech 41. In a variant, the exhaust manifold 20 may, however, be brought relative to the breech 41.

In order to obtain a thermal gain during the passage of the exhaust gas through the redirection pipe 40, the pipe 40 advantageously extends between two water cores, preferably an upper water core 49 and a lower water core 50 of the cylinder head 41, as can be seen in FIGS. 4 and 5. The "upper" and "lower" space indications refer to the engine in the mounting or operating position in a motor vehicle disposed on a horizontal plane.

Thus, the exhaust gas from the exhaust manifold 20 are cooled by the two water cores 49, 50 to the valve EGR 25. This architecture allows to cool the recirculated gases of the order of 200 ° C, which allows a better thermal resistance of the EGR valve 25.

As can be seen clearly in Figure 6, an attached support 46, for example made of aluminum, is fixed to the cylinder head 41 and is intended to receive the valve 25. For this purpose, the support 46 comprises a first fixing interface 47 to allow attachment of the support 46 on the yoke 41, so that an inlet opening of the valve 25 is positioned opposite an outlet end of the redirection pipe 40. For this purpose, the first attachment interface 47 has openings for the passage of fasteners, such as screws, in three or four attachment areas.

In addition, the support 46 includes a second attachment interface 48 to allow attachment of the heat exchanger 14 on the support 46, so that an outlet opening of the valve 25 is positioned opposite the an input of the heat exchanger 14. For this purpose, the second attachment interface 48 comprises openings for the passage of fasteners, such as screws in three or four attachment areas.

In an alternative embodiment, the interface support 46 is integrated with the cylinder head 41.

The invention thus allows, thanks to the positioning of the redirection pipe 40 through the yoke 41, to increase the compactness of the engine, which allows the integration for example of other functionalities minimizing the emission of pollutant from a motor vehicle. Furthermore, the invention also allows a thermal gain since the gases from the exhaust manifold 20 are cooled by the upper water cores 49 and lower 50 of the cylinder head 41.

In certain configurations, the EGR exchanger 14 may optionally comprise an exhaust gas bypass line allowing the gas to bypass the cooling ducts of the exchanger 14 and an inner flap (not visible in the figures ) for managing the amount of recirculated gas that will be cooled by the exchanger 14 and the amount of recirculated gas that will not be.

Claims (9)

1. Internal combustion engine (5) comprising: - a cylinder head (41), - an exhaust gas redirection pipe (40) capable of redirecting a portion of the exhaust gases from an exhaust manifold ( 20) to an inlet (51) of said internal combustion engine (5), characterized in that said redirection duct (40) is integrated with said cylinder head (41) and connected to said exhaust manifold (20) via a quill ( 43) formed in a wall of said exhaust manifold (20). 2. Internal combustion engine according to claim 1, characterized in that said redirection pipe (40) extends between two water cores (49, 50). 3. Internal combustion engine according to claim 2, characterized in that said water cores (49, 50) respectively correspond to an upper water core (49) and a lower water core (50) of said cylinder head (41). 4. Internal combustion engine according to any one of claims 1 to 3, characterized in that said exhaust manifold (20) is integrated with said cylinder head (41). 5. Internal combustion engine according to any one of claims 1 to 4, characterized in that an output of said redirection pipe (40) is in communication with a valve (25) adapted to manage a quantity of gas of exhaust passing through a heat exchanger (14) which is in communication with an intake manifold (45) of said internal combustion engine (5). 6. Internal combustion engine according to claim 5, characterized in that it comprises an attached support (46) fixed on said cylinder head (41) and intended to receive said valve (25). 7. Internal combustion engine according to claim 6, characterized in that said support (46) comprises a first attachment interface (47) to allow attachment of said support (46) on said cylinder head (41) so that an opening the inlet of said valve (25) is positioned opposite an exit end of said redirection pipe (40). 8. Internal combustion engine according to claim 7, characterized in that said support (46) comprises a second attachment interface (48) to allow attachment of said heat exchanger (14) on said support (46) so that an outlet opening of said valve (25) is positioned opposite an inlet of said heat exchanger (14). 9. Motor vehicle comprising an internal combustion engine (5) as defined in any one of the preceding claims.