FR2954955A1 - Engine e.g. diesel engine, for motor vehicle, has collector and air supply line that comprises recirculation loop for recirculation of exhaust gas, and cooler for cooling part of gas circulating in loop - Google Patents

Abstract

The engine (12) has an exhaust gas collector (20) and an air supply line (14) that comprises a recirculation loop (10) for recirculation of exhaust gas. An inlet (22) of the recirculation loop is connected to the collector. A filter (26) is arranged in the inlet, and stops particles with a catalytic phase. The line comprises a cooler (44) for cooling a part of gas circulating in the loop. The line comprises an air stopper that is connected to air conduits (50) to separate the air conduits from air. The catalytic phase includes an active oxidation phase and oxidation phase that include elements chosen among a group consisting of transition metal oxides and rare earth oxides. The catalytic phase comprises a noble metal that is chosen in a group consisting of platinum and palladium.

Description

ENGINE COMPRISING AN AIR LINE WITH AN EXHAUST GAS CIRCULATION LOOP

The present invention relates to a motor comprising an air line with an exhaust gas recirculation loop. [0002] The combustion of fossil fuel such as oil or coal in a combustion system, in particular diesel fuel in a diesel engine, can lead to the production of a significant quantity of pollutants that can be discharged by the exhaust into the combustion chamber. environment and cause damage. Among these pollutants, the emission of nitrogen oxides called NO, poses a problem since these gases are suspected to be one of the factors contributing to the formation of acid rain and deforestation. An exhaust gas recirculation loop (or "Exhaust gas recirculation" EGR in English) is a system introduced in the 70s in the air lines which consists in redirecting a portion of the exhaust gas internal combustion engines to the intake. A re-circulation loop makes it possible to reduce the formation of nitrogen oxides in the combustion chamber. A recirculation loop generally comprises a valve which makes it possible to determine the amount of re-circulated exhaust gas which is reintroduced at the intake. The loop may also include an exchanger whose role is to cool the re-circulated exhaust gas to improve the efficiency of the recirculation loop. The use of an air line having an exhaust gas recirculation loop in an engine can cause the formation of particle deposits in the air line. Such fouling of the line may then affect all parts downstream of the loop or affected by the flow back ("back flow" in English). The distributor, the cylinder head ducts, the intake valves, the possible sensors including the temperature and pressure sensors used for the regulation of the air line, the air metering units as well as the hoses or the bypass. Pass of the upstream air line of the re-circulated exhaust gases are part of the parts that can be affected by clogging of the loop. In the particular case of a motor powered by supercharged air, the turbocharger for supercharging can also be fouled. The supercharged air can be cooled by a heat exchanger coolant supercharged. The heat transfer fluid may in particular be water. Such use of the exhaust gas recirculation loop through supercharged air cooling can cause the supercharged air cooler to lose its thermal efficiency and permeability if deposits foul it. The deposits at the supercharged air cooler, the valve and the distributor are of different natures because of different physicochemical mechanisms. Thus, the deposits of the supercharged air cooler are formed mainly by thermophoresis that is to say by attraction on a cold wall of particles moving under the action of a thermal gradient. In the valve, diffusionphorsis and condensation are the predominant phenomena. As a result, the species that settle on the wall at the valve are rather hydrocarbons. The major compounds of the deposits in the distributor are hydrocarbons generally comprising between 10 and 36 carbon atoms in the carbon chain. Such hydrocarbons come mainly from the fuel and the thermocaisaillement of the engine oil. In addition, the deposits vary according to different parameters. By way of illustration, the temperature of the gases, the temperature of the walls, the speed of the gases, the nature of the fuel, the type of combustion and the nature of the oil used are parameters which influence the nature of the deposits which can foul the re-circulation loop. The supercharged air lines may further include a bypass (also known by the English name "by-pass") of air that separates the air from the turbocharger. Deposits can cause the loop valve or manifold to squeeze into the closed position increasing the amount of pollutants released by the vehicle into the atmosphere. The valve can also lock in the open position. The engine can in such a case not start and combustion become unstable. The thermal efficiency and the permeability of the exchanger of the loop can be greatly reduced during a clogging of the exchanger. In addition, the deposits can ignite on contact with an incandescent particle. A high gas temperature or a flame front from the combustion chamber are other mechanisms that can lead to ignition of the deposits. For example, a deposit in the distributor may ignite if the surrounding temperature is maintained for a few minutes at 180 ° C. Inflammation of deposits can lead to malfunctions of parts affected by deposits. It is therefore desirable to avoid the formation and ignition of deposits in the line comprising the recirculation loop and the distributor. [000s] It is known from US 2008/0041051 an internal combustion engine comprising an exhaust gas path and an air supply system for the combustion of air. A compressor of an exhaust gas turbocharger is arranged in the air supply system for the combustion of air. An exhaust turbocharger turbine, a first particulate filter, and an adjustable exhaust throttle are arranged in series in a downstream direction in the exhaust path. A low pressure re-circulated exhaust line branches off the exhaust path downstream of a first particulate filter and discharges into the air supply system for combustion upstream of the compressor. A re-circulated exhaust gas cooler, a re-circulated exhaust gas valve and a second particulate filter with a mesh filter of at least 50 μm are arranged in the exhaust gas line. circulated at low pressure. It is also known from WO-A-2007/136148 an exhaust gas purification device for a diesel engine comprising a catalytic unit for reducing nitrogen oxides and a diesel particulate filter unit arranged successively. upstream of an exhaust gas flow. The device further comprises a diesel fuel injector disposed at a front end portion of the catalytic unit for reducing nitrogen oxides and an exhaust gas recirculation line for entering a portion of the exhaust gas from a rear end of the diesel particulate filter unit to an intake manifold of an engine. The exhaust gas recirculation line has no additional control valve or controller. Other devices comprising a loop for recirculating gases are also known from EP-B1-1 331 388, US-B1-6 474 319, US-A-6,003,303, US-A-2006. / 0137330, JP-A-2003-106220 and WO-A-2006/100072. However, the aforementioned devices do not provide suitable solutions to obtain good durability of the engine. There is therefore a need for a device to ensure a good durability of an engine with an air line having an exhaust gas recirculation loop without reducing the performance of the engine. For this, the invention provides a motor, comprising an exhaust gas manifold and an air supply line, said line comprising an exhaust gas recirculation loop comprising an inlet, connected to the collector, in which is disposed a particulate stop filter with a catalytic phase, characterized in that the line further comprises a coolant air cooler coolant adapted to cool at least a portion of the gas flowing in the loop. The filter is, for example, a filter for stopping incandescent particles. In a variant, the line further comprises a first and a second air duct, the first duct comprising the cooler, and an air divider connected to the first and second air ducts adapted to separate from the duct. air between the two ducts. In a variant, the line further comprises a gas cooling exchanger of the exhaust gas recirculation loop, the exchanger and the supercharged air cooler being placed in series. In a variant, the line further comprises a gas cooling exchanger of the exhaust gas recirculation loop, a first and a second branch, the first branch conveying the exhaust gas to the cooler and the second branch comprising the exchanger, a metering valve for the amount of exhaust gas re-circulated, the valve being adapted to separate the gases from the recirculation loop of exhaust gas between the two branches. In a variant, the catalytic phase comprises a catalyst for oxidizing hydrocarbons. In a variant, the filter is a metal structure with a mesh size of between 0.5 mm 2 and 4 mm 2, preferably between 0.5 mm 2 and 2 mm 2. In a variant, the catalytic phase comprises an active oxidation phase, whose charge in the catalytic phase is preferably between 100 and 150 g / l and which comprises one or more elements chosen from a group comprising the oxides of transition metals, rare earth oxides and combinations of transition metal oxides and rare earth oxides. In a variant, the catalytic phase comprises at least one precious metal, selected from a group comprising platinum, palladium or a combination of both, the precious metal charge being between 0.03 and 0.7 g / L. In a variant, the catalytic phase comprises a combination of platinum and palladium, the ratio between platinum and palladium being less than 2. [0021] In a variant, the catalytic phase further comprises a zeolite type material. , the zeolite material filler in the catalytic phase being less than 50 g / l. In a variant, the catalytic phase comprises a part with an active oxidation phase, a combination of platinum and palladium, zeolite type materials such as: • the active phase oxidation charge in the catalytic phase is between 100 and 150 g / L, • the precious metal charge in the catalytic phase is between 0.03 and 0.35 g / L, • the ratio of platinum to palladium is less than 1 and • the load in zeolite type materials is 50 g / l.

In a variant, the catalytic phase comprises a part with an active oxidation phase, a combination of platinum and palladium, zeolite type materials such that: the catalytic phase comprises a part with an active phase of oxidation, a combination of platinum and palladium, zeolite type materials such as • the active phase oxidation charge in the catalytic phase is between 100 and 150 g / L, • the precious metal charge in the catalytic phase is between 0.35 and 0.7 g / L, • the ratio between platinum and palladium is between 1 and 2 and • the load of zeolite type materials is less than 30 g / L.

In a variant, the filter comprises four oval opening cylinders. Other features and advantages of the invention will appear on reading the following detailed description of the embodiments of the invention, given by way of example only and with reference to the drawings which show: FIG. 1 a schematic view of a vehicle engine; • Figure 2, a schematic view of an example of a vehicle engine equipped with a turbocharger; • Figure 3, a schematic view of another example of a vehicle engine equipped with a turbocharger; • Figure 4, a schematic view of another example of a vehicle engine equipped with a turbocharger; and FIG. 5, a schematic view of another example of a vehicle engine equipped with a turbocharger; Figure 6, an air line for the air supply of the engine; • Figure 7, a thermogravimetric analysis. There is provided an air line for supplying air to an engine, in particular an engine of a motor vehicle, comprising an exhaust gas recirculation loop comprising an inlet adapted to be connected to an engine collector. The loop further comprises a filter for stopping large particles (greater than 1 mm 2) with a catalytic phase, the filter being at the entrance of the loop. The line further comprises a supercooled coolant cooler adapted to cool at least a portion of the loop gases. The loop of the line makes it possible to stop particles capable of igniting the deposited particles, to limit the fronts flames and oxidize the hydrocarbons passing through the filter. The use of a particulate filter prevents ignition of deposits present in the air line (ducts, metering devices, distributors, bypass ...) and especially at the supercharged air cooler. The phenomenon of fouling is limited by ensuring a conversion of hydrocarbons by the presence of the catalytic phase. This further allows the use of an unconventional configuration in which the supercharged air cooler is more exposed to particle deposition because gases in the exhaust gas recirculation loop are cooled by the cooler. The proper functioning of the cooler is thus preserved while improving the cooling of the re-circulated exhaust gas. The line comprising the proposed loop and the use of the cooler to cool the re-circulated exhaust gas thus make it possible to improve the durability of the engine without affecting the performance of the engine. Such a line 14 comprising a re-circulation loop 10 can be implemented in a vehicle engine 12 as shown in FIG. 1. The air line 14 is partially shown in FIG. More complete representations can be found in Figures 2 to 5. The engine 12 can be any type of engine. The engine 12 can in particular use any fuel such as gasoline, diesel, biofuels or LPG. The engine 12 includes one or more combustion chambers 16 located between an intake manifold 18 and an exhaust manifold. The inlet distributor 18 receives air to be introduced into the combustion chamber 16 via the air line 14. Fuel is also injected into the combustion chamber 16 generally via an injection nozzle which is not The exhaust manifold receives the emissions of gases produced by the combustion and directs them to an exhaust line 21 which comprises an unillustrated exhaust catalyst. The catalyst processes the emissions produced by the combustion prior to expulsion to the outside atmosphere. In the particular case of the diesel vehicle, the exhaust line 21 may be further equipped with a particulate filter (FAP) placed after the catalyst. Such a particle filter makes it possible to eliminate the fine particles contained in the exhaust gases of diesel engines. The motor 12 comprises a loop 10 of recirculation of the exhaust gas (or "Exhaust gas recirculation" EGR in English). The loop 10 redirects a portion of the exhaust gas of the internal combustion engines to the intake. The emissions of pollutants are reduced in the presence of the loop 10. The loop 10 comprises an inlet 22 adapted to be connected to the collector 20.

According to the example of Figure 1, the manifold 20 comprises four parallel branches 32 leading to the chambers 16, the inlet 22 being a fifth branch parallel to the four branches 32. The loop 10 further comprises a filter 26 for stopping particles with a catalytic phase. The filter 26 makes it possible to intercept particles of metallic or organic origin. Filter 26 also serves as flame arrestor.

The filter 26 is at the inlet 22. The loop 10 makes it possible to limit the fouling of the parts placed downstream of the filter 26. Thus, according to the example of FIG. 1, the loop 10 limits the fouling of the filter. a valve 28 which allows to dose the amount of re-circulated exhaust gas introduced to the intake. This avoids positioning the valve 28 in a hot environment unfavorable to the formation of deposits. The use of the loop 10 thus allows the repositioning of the valve 28 in a position in which the environment is colder. The life of the valve 28 is thus increased. The loop 10 also limits the fouling of an exchanger 30 for cooling the recirculated exhaust gas. The fouling of the distributor 18 also placed downstream of the filter 26 is also reduced. The loop 10 also reduces the risk of self-ignition deposits that can form on the parts downstream of the loop 10. The risk of damage and melting downstream parts such as the distributor 18 for example are also reduced. The presence of the catalytic phase also makes it possible to limit the creation of deposits. The performance of the loop 10 is furthermore not degraded, which makes it possible to better comply with the regulations on the emission of pollution, particularly with regard to nitrogen oxides (NOx). The loop 10 thus makes it possible to increase the durability of the engine 12 without reducing the performance of the engine 12. The loop 10 also makes it possible to use an unusual configuration in which a supercharged air cooler with heat transfer fluid, not shown. Figure 1 cools a portion of the re-circulated gases. Examples of configuration of the air line 14 for such cooling are described below with reference to FIGS. 2 to 5. This is because the greater exposure of the supercharged air cooler to the deposition of particles in such a configuration. leads to an increased risk of fouling. But, the decrease in fouling due to the loop 10 compensates for such a larger exposure. The supercharged air cooler can therefore function properly while cooling the exhaust gases better. Due to this decrease in temperature, the motor 12 produces fewer particles, which further improves the reduction in the fouling of the parts placed downstream of the filter 26. The line 14 comprising the loop 10 coupled to the use of a supercharged air cooler to cool the re-circulated exhaust gas thus makes it possible to increase the durability of the engine 12 without reducing the performance of the engine 12. [0033] FIGS. 2 to 5 each represent a view schematic of an example of a vehicle engine 12 equipped with a turbocharger. In each of Figures 2 to 5, there is shown a motor 12 supplied with supercharged air from a turbocharger 42 air. The turbocharger 42 makes it possible to increase the density of the air taken outside. The air taken outside is filtered by an air filter and passes through a flow meter to control the flow of air injected into the turbocharger 42. To operate, the turbocharger 42 recovers energy from the exhaust gas before their passage through the catalyst 58 and the particulate filter 60 of the exhaust line 21. According to the example of FIGS. 2 to 5, the exhaust line 21 thus passes through the turbocharger 42. [0035] In addition, the temperature of the compressed air is generally reduced to increase the efficiency of the supercharging which allows the combustion of more fuel in the engine 12. This is why the air from the turbocharger 42 is at least partially cooled by a cooler 44 supercharged air coolant. The heat transfer fluid may in particular be water or water containing glycol. The quantity of air actually injected into the distributor 18 of the motor 12 is controlled by means of a metering valve 46. According to the example of Figure 2, the re-circulated exhaust gas is mixed with the air from the turbocharger 42 before being cooled by the supercharged air cooler. The supercharged air cooler therefore cools both the re-circulated exhaust gas and the air from the turbocharger 42. Such a configuration makes it possible to eliminate both a possible heat exchanger dedicated to the cooling of the exhaust gases. -circulated and a possible differentiator. The risks associated with the fouling of such an exchanger or such a diverter are therefore eliminated. In addition, the size is reduced. The implantation of the engine 12 in the under-hood environment of the vehicle is thus facilitated. According to the example of Figure 3, the air line 14 further comprises a first duct 50 of air and a second duct 52 of air. The two ducts 50 and 52 connect an air divider 48 to the metering valve 46. The first duct 50 comprises the cooler 44. The air diverter 48 or "by-pass" valve is adapted to separate air between the two ducts 50, 52. Therefore, in the case of FIG. , the supercharged air can be separated between a cooled part by the supercharged air cooler 44 and a non-cooled part by the supercharged air cooler 44. This allows in particular to control the temperature of the gas at the level of the metering valve 46. In addition, such a configuration eliminates a possible heat exchanger dedicated to cooling the re-circulated exhaust gas. The risks associated with the fouling of such an exchanger are therefore eliminated. In addition, the size is reduced. The implantation of the engine 12 in the under-hood environment of the vehicle is thus facilitated. According to the example of Figures 4 and 5, the air line 14 comprises the first duct 50 of air and the second duct 52 of air. The two ducts 50 and 52 connect the air divider 48 to the metering valve 46. The first duct 50 comprises the cooler 44. The air diverter 48 or "by-pass" valve is adapted to separate air between the two ducts 50, 52. Therefore, in the case of FIGS. 5, the supercharged air from the turbocharger 42 can be separated between a cooled portion by the supercharged air cooler 44 and a non-cooled portion by the supercharged air cooler 44. This allows in particular to control the temperature of the gas at the level of the metering valve 46. In addition, for the case of Figure 4, there is provided a line 14 comprising a gas cooling exchanger 30 of the exhaust gas recirculation loop. The exchanger 30 and the cooler 44 of supercharged air are placed in series. The term "series" means that the recirculated exhaust gas is successively cooled by the exchanger 30 and then by the cooler 44. Thus, the exchanger 30 is placed in a branch 54 between the diverter 48 and the valve 28, the branch 54 conveying the exhaust gas to the cooler 44.

The cooler 44 is placed between the diverter 48 and the metering valve 46, in the conduit 50. This ensures a cooling of the recirculated exhaust gas which is still better. Due to this reduction in temperature, the motor produces fewer particles, which further improves the reduction in the fouling of the parts placed downstream of the filter 26. According to the example of FIG. 5, the line 14 further comprises a gas cooling exchanger 30 of the exhaust gas recirculation loop. The line 14 also comprises a first branch 54 and a second branch 56. According to FIG. 5, the first branch 54 is connected from the valve 28 to the first duct 50. The duct 50 comprises the cooler 44. The first branch thus carries the gases The second branch 56 conveys the exhaust gases from the valve 28 to the distributor 18. The second branch 56 comprises the exchanger 30. The line also comprises a valve 28 for dosing the amount of gas. exhaust gas re-circulated. The valve 28 is adapted to separate the gases from the loop 10 for recirculating exhaust gas between the two branches 54, 56. This makes it possible to control the temperature of the re-circulated exhaust gases admitted into the engine 12. in particular because the gases are better cooled by the cooler 44. More specifically, when it is desired that the temperature of the re-circulated exhaust gas be decreased, the proportion of re-circulated exhaust gas circulating in the first branch 54 is increased which increases the proportion of re-circulated exhaust gas cooled by the cooler 44. Conversely, when it is desired that the temperature of the re-circulated exhaust gas be increased, the proportion of gas re-circulated exhaust circulating in the second branch 56 is increased which increases the proportion of re-circulated exhaust gas cooled by the exchanger 30. The different implantations data are given by way of example and other configurations are possible. In all the implantations described, the filter 26 may in particular be a filter 26 for stopping incandescent particles. An incandescent particle is a particle that emits light under the effect of a high temperature. By extension, a particle which is adapted to cause the ignition of a deposit of a wall is considered as an incandescent particle. The presence of a filter 26 for stopping incandescent particles makes it possible to further limit the risks of ignition of the deposits on the walls of the re-circulated exhaust gas loop. The filter 26 may be a metal structure. The metal structure may in particular be a wire mesh or a metal foam. The use of a metal structure avoids the pollution of parts placed downstream of the loop 10. The risk of galling of the valve 28 are particularly particularly reduced. The permeability of the loop 10 is thus optimized. In addition, a metal structure is resistant to thermal constraints imposed. The metal structure may have between 100 and 600 cells per square inch, or between 15 cells per square centimeter and 100 cells per square centimeter.

Such a choice makes it possible to avoid the formation of a backpressure and takes into account the temperatures at the filter 26. Preferably, the structure comprises between 300 and 600 cells per square inch, or between 40 cells per square centimeter and 100 cells per square centimeter. square centimeter, which results in an increase in the catalytic efficiency of the filter 26. The filter 26 has a mesh size of between 0.5 mm 2 and 4 mm 2. Such values make it possible not to let the incandescent particles pass. The filter 26 thus allows a filtration efficiency of the incandescent particles which may be greater than 85%. In addition, the pressure difference generated is low because the filter 26 allows radial diffusion of the flow of re-circulated exhaust gas passing therethrough. Preferably, in order to limit the risk of clogging created by the environmental temperatures and the flow rate of the gases passing through the collector 20, the mesh size is between 0.5 mm 2 and 2 mm 2. The catalytic phase may comprise a hydrocarbon oxidation catalyst. The use of such a catalyst makes it possible to prevent the formation of deposits, in particular in the distributor 18 or the valve 28. The catalytic phase of the filter 26 may also comprise an active oxidation phase also called "coating". or "wash-coat" in English. The active oxidation phase promotes the oxidation of hydrocarbons. This prevents clogging of the loop 10. The elements of the active oxidation phase may be transition metal oxides or rare earth oxides. By way of example, alumina (Al2O3), silica (SiO2), titanium oxide (TiO2), ceria (CeO2), zirconia (ZrO2) or lanthanum oxide (La2O3) may be used. Any other oxide which exhibits properties in oxidation catalysis is also likely to be employed in the composition of the active oxidation phase. In addition, the oxides can be used in combination, for example a combination of silica with alumina SiO 2 / Al 2 O 3 or a mixture of cerine (CeO 2) and zirconia (ZrO 2). The active phase oxidation charge in the catalytic phase may be between 50 and 200 g / l. This corresponds to a compromise between the desired hydrocarbon oxidation efficiency and the counter-pressure generated by the catalytic phase which prevents the passage of part of the exhaust gas. Preferably, the active phase oxidation charge in the catalytic phase is between 100 and 150 g / l. This makes it possible to obtain a compromise between the oxidation of the hydrocarbons and the back pressure generated even better. [ooso] The catalytic phase may comprise at least one precious metal. The presence of precious metals makes it possible to increase the oxidation efficiency of the catalytic phase. The fouling of the loop 10 of recirculation of exhaust gas is thus reduced. The precious metal charge in the catalytic phase can vary from 1 to 200 g / ft3, ie from 0.03 g / l to 7 g / l. This makes it possible to obtain a good oxidation efficiency of the hydrocarbons taking into account the temperature of the collector 20. Preferably, the charge of precious metal in the catalytic phase is between 1 and 20 g / ft 3, ie between 0.degree. 03 g / L and 0.7 g / L. This makes it possible to further improve the oxidation efficiency of the hydrocarbons. By way of illustration, the precious metal may be a member selected from a group comprising platinum, palladium or a combination of both. The addition of such precious metals increases the oxidation efficiency of the filter 26. The combination of platinum and palladium is particularly advantageous because such a mixture ensures that a precious metal is active for all ranges of temperature. Platinum is indeed active at low temperature but not very resistant to high temperature. Palladium is less active at low temperatures but more resistant to high temperature. In the case where the catalytic phase comprises a combination of platinum and palladium, a ratio of platinum to palladium less than 2 further improves the oxidation efficiency of the hydrocarbons. Such a compromise results from the fact that the filter 26 is implanted in a relatively hot space. The catalytic phase may further comprise a zeolite type material.

The zeolite type materials belong to the family of aluminosilicates and are also called "HC traps". Such materials do indeed have cold hydrocarbon trapping properties. The presence of zeolite type material in the catalytic phase makes it possible to improve the efficiency of the filter 26 for cold temperatures. The load of zeolite type material in the catalytic phase is less than 50 g / l. This makes it possible to obtain good oxidation efficiency of the hydrocarbons at low temperature. The catalytic phase can comprise several parts. This makes it possible to further improve the efficiency of the filter 26. [0058] A part may comprise an active oxidation phase, a combination of platinum and palladium and zeolite type materials. The active phase oxidation charge in the catalytic phase is between 100 and 150 g / l. The charge of precious metals in the catalytic phase is between 1 and 10 g / ft 3, ie between 0.03 and 0.35 g / l. The ratio of platinum to palladium is less than 1 and the load of zeolite materials is 50 g / L. Such a part is particularly effective for the oxidation of the hydrocarbons coming out of the chamber 16. It is thus advantageous to place this first part upstream in the filter 26 in the direction of flow of the re-circulated exhaust gases, manifold 20 to manifold 18. [0059] Another part may comprise an active oxidation phase, a combination of platinum and palladium and zeolite type materials. The active phase oxidation charge in the catalytic phase is between 100 and 150 g / l. The charge of precious metals in the catalytic phase is between 10 and 20 g / ft 3, ie between 0.35 and 0.7 g / l. The ratio of platinum to palladium is between 1 and 2 and the load of zeolite materials is less than 30 g / l. Such a part is particularly effective for the oxidation of the hydrocarbons which have passed through most of the filter 26. It is thus advantageous to place this second part downstream in the filter 26 in the direction of flow of the exhaust gases. circulated, manifold 20 to the distributor 18. The implantation of the filter 26 is at the input 22 adapted to be connected to the collector 20. The filter 26 is thus placed at the beginning of the loop 10 of exhaust gas recirculation. This makes it possible to guarantee protection for a large part of the loop 10. At the inlet 22, the mean incoming temperatures are 350 ° C. and range from a minimum of 200 ° C. to 800 ° C. . The maximum temperature of the wall is between 500 ° C and 800 ° C. The maximum gas temperature is 600 ° C during operation of the exhaust gas recirculation loop 10. The temperature of the gases is 850 ° C when the valve 28 is closed. The minimum gas flow rate is 4 g / s and the maximum flow rate is 33 g / s, the average flow rate being 9 g / s. In addition, the maximum radial exotherm temperature is 30 ° C and the maximum longitudinal exotherm temperature of 20 ° C per 1000 ppm of hydrocarbon passing through the filter 26. [0062] To integrate the filter 26 at the level of At the inlet 22, the filter 26 may comprise one or more oval-shaped cylinders. Such a configuration has the advantage of being easy to implement. The opening can also be of another form and in particular parallelepiped. The volume of the filter 26 may be 20 to 40 cm3. The ratio between the diameter over the length of the filter 26 can be between 0.15 and 2. The filter 26 can thus be integrated at the input 22, the input 22 being adapted to be connected to any type of collector 20. The manifold 20 may in particular be cast iron, cooled aluminum, steel or welded mechanical sheet.

Claims (10)

REVENDICATIONS1. Motor (12) comprising an exhaust gas manifold (20) and an air supply line (14), said line comprising an exhaust gas recirculation loop (10) having an inlet (22) connected to it at the collector (20), in which is arranged a filter (26) for stopping particles with a catalytic phase, characterized in that the line (14) further comprises a cooler (44) of supercharged air with fluid coolant adapted to cool at least a portion of the gas flowing in the loop (10). 2. The engine according to claim 1, characterized in that the line (14) further comprises a first and a second duct (50, 52) of air, the first duct (50) comprising the cooler, and a diverter ( 48) connected to the first and second air ducts (50, 52) adapted to separate air between the two ducts (50, 52). 3. The engine according to claim 1 or claim 2, characterized in that the line (14) further comprises a heat exchanger (30) for cooling the gases of the exhaust gas recirculation loop, the exchanger (30) and the supercharged air cooler (44) being in series. 4. The engine according to claim 1 or claim 2, characterized in that the line (14) further comprises a heat exchanger (30) for cooling the gases of the exhaust gas recirculation loop, a first and a second branch (54, 56), the first branch (54) conveying the exhaust gases to the cooler (44) and the second branch (56) comprising the exchanger (30), a valve (28) for dosing the the amount of exhaust gas re-circulated, the valve (28) being adapted to separate the gases from the exhaust gas recirculation loop between the two branches (54, 56). 5. The engine according to any one of the preceding claims, characterized in that the catalytic phase comprises a hydrocarbon oxidation catalyst. 6. The engine according to any one of the preceding claims, characterized in that the filter (26) is a metal structure with a mesh size between 0.5 mm 2 and 4 mm 2, preferably between 0.5 mm 2 and 2 mm2. 7. The engine according to any one of the preceding claims, characterized in that the catalytic phase comprises an active oxidation phase, whose charge in the catalytic phase is preferably between 100 and 150 g / L and which comprises one or several elements selected from a group comprising transition metal oxides, rare earth oxides and combinations of transition metal oxides and rare earth oxides. 8. The engine according to any one of claims 1 to 7, characterized in that the catalytic phase comprises at least one precious metal, selected from a group comprising platinum, palladium or a combination of both, the precious metal charge being between 0.03 and 0.7 g / L. 9. The engine according to any one of the preceding claims, wherein the catalytic phase further comprises a zeolite type material, the zeolite material filler in the catalytic phase being less than 50 g / L. 10. The engine according to any one of the preceding claims, characterized in that the filter (26) comprises four cylinders with oval opening.