EP2881576A1 - Recirculated exhaust gas distribution device and corresponding intake manifold and intake module - Google Patents

Abstract

The invention relates to a device (11) for distributing recirculated exhaust gas from an intake manifold (3) for an air intake module, configured to supply at least one cylinder of an internal combustion engine, a flow of air comprising intake gases and / or recirculated exhaust gas (EGR), the distribution device (11) comprising a recirculated exhaust gas distribution channel (13), the distribution (13) comprising a first injection means (15) of recirculated exhaust gas in the air stream for supplying at least one cylinder.

According to the invention, the dispensing device (11) further comprises a control member (17) arranged in the distribution channel (13) and configured to modulate the flow of recirculated exhaust gas injected by the first means of injection (15).

Description

The present invention relates to the general field of air supply of motor vehicle engines, and more particularly to engines whose supply air comes from a compressor or a turbocharger. The invention more particularly relates to multicylinder engines and devices used to distribute recirculated exhaust gas streams to the cylinders.

The motors concerned by the invention can be spark ignition or compression ignition (diesel engine). The engines can be supercharged or powered at atmospheric pressure.

A motor vehicle engine has a combustion chamber, generally formed by a plurality of cylinders, in which a mixture of oxidant and fuel is burned to generate the engine work. The gases admitted into the combustion chamber are called intake gases. They include air that is called supercharging air when it comes from a compressor.

In order to increase the density of the charge air, these gases are generally cooled before being introduced into the combustion chamber. This function is fulfilled by a heat exchanger, also called charge air cooler known under the abbreviation "RAS".

In order to reduce the polluting emissions, it is known to introduce into the flow of intake gas, so-called "recirculated" exhaust gases, known to those skilled in the art under the abbreviation "EGR" corresponding to "Exhaust Gas recirculation. This is exhaust gas taken downstream of the combustion chamber to be re-routed (recirculated) to the intake gas stream, upstream of the combustion chamber, where they are mixed with the charge air for admission to the combustion chamber.

With a view to the admission into the cylinder head of a motor vehicle engine of a supercharging air flow comprising a flow of intake gas that is fresh air and / or a flow of recirculated exhaust gas, an intake manifold intended to be mounted on the cylinder head of the engine allows the possible mixing of the fresh air flow and the flow of recirculated exhaust gas, and the distribution of the mixture in the cylinder head.

In this case, recirculated exhaust gas conveying means are provided in the intake manifold for the distributed injection of the recirculated exhaust gas into the supercharging air stream.

According to a known solution, the recirculated exhaust gas, called EGR gas, is introduced into the intake manifold via a distribution channel arranged transversely to the flow of the charge air, opening for example through downstream of the charge air cooler and having a few injection holes which allow the recirculated exhaust gas to flow into the volume of the intake manifold.

The recirculated exhaust gas can mix with the intake gases from, for example, the charge air cooler. The mixture is then directed to outlet channels to feed the cylinder (s) of the engine.

However, the size and position of the injection holes are fixed. Indeed, the size and the arrangement of the holes are predefined for a certain operating range of the engine and can not be modified during engine operation.

By way of example, injection holes having a certain diameter make it possible to obtain an exhaust gas rate in the cylinders that satisfies for an engine speed around 1250 rpm. However, with this same diameter the rate of exhaust gas recirculated in the cylinders is not satisfactory for an engine speed around 2000rpm. The opposite is also valid.

In conclusion, it is necessary to choose a size that fits well for a range of regime, but not for others. This leads to an optimal distribution limited to a narrow operating range of the engine.

For this purpose, the subject of the invention is a recirculated exhaust gas distribution device of an intake manifold for an intake module of air configured to supply at least one cylinder of an internal combustion engine, an air stream comprising intake gases and / or recirculated exhaust gas, the distribution device comprising a gas distribution channel recirculated exhaust, the distribution channel comprising a first exhaust gas injection means recirculated in the air flow for supplying at least one cylinder,
characterized in that the dispensing device further comprises a control member arranged in the distribution channel and configured to modulate the flow of recirculated exhaust gas injected by the first injection means.

Such a distribution device optimizes the distribution of recirculated exhaust gas for several operating points of the engine, for example for a range of engine speed of the order of 1250 to 2500 rpm.

Indeed, the control member allows an active modulation of the recirculated exhaust gas flow injected into the supercharging air flow, by modifying the passage section of the recirculated exhaust gas flow injected by the first d injection into the supercharging air flow in particular depending on the engine conditions.

According to one embodiment, the control member is rotatable and is configured to modulate the flow of recirculated exhaust gas as a function of the angular position of the rotary control member. It may be for example a rotary plug, or a rotary flap, such as a butterfly-type flap.

According to an alternative embodiment, the control member is movable in translation. It may be for example a mobile flap in translation of the guillotine type.

According to one aspect of the invention, the first injection means comprises at least one first injection hole and the control member is shaped so as to adjust the dimensions of the first injection hole.

The control member makes it possible to vary the size or size of the first injection holes as a function of the engine speed, and consequently allows a precise exhaust gas distribution according to different engine conditions.

With such a control member it is also possible to completely close the first injection holes, and thus to avoid any flow of recirculated exhaust gas in the path of fresh air.

It is then possible to eliminate the exhaust gas distribution valve provided in the solutions of the prior art for the metering of exhaust gas introduced into the distribution channel. It is therefore no longer necessary to provide at the intake manifold a connection interface of the distribution channel to such a valve. This results in a reduction of costs.

• l'organe de contrôle comporte un deuxième moyen d'injection de gaz d'échappement recirculés comprenant au moins un deuxième trou d'injection, et l'organe de contrôle est apte à être agencé dans une position permettant la mise en communication fluidique entre un premier trou d'injection et un deuxième trou d'injection associés, l'organe de contrôle étant par exemple un boisseau rotatif,
• le nombre de deuxièmes trous d'injection de l'organe de contrôle est le même que le nombre de premiers trous d'injection,
• le canal de distribution est apte à être agencé sensiblement transversalement par rapport à l'écoulement du flux d'air dans le module d'admission,
• l'organe de contrôle est apte à être agencé sensiblement transversalement par rapport à l'écoulement du flux d'air dans le module d'admission,
• l'organe de contrôle est réalisé sous forme d'un tube sensiblement cylindrique, tel qu'un boisseau,
• ledit dispositif comprend au moins un moyen de rappel agencé de manière à solliciter l'organe de contrôle vers une position prédéfinie de sécurité. Il peut s'agir par exemple d'un ressort de rappel.

The dispensing device may further comprise one or more of the following features, taken separately or in combination:

• the control member comprises a second recirculated exhaust gas injection means comprising at least one second injection hole, and the control member is adapted to be arranged in a position allowing the fluidic communication to be put into place between a first injection hole and a second injection hole associated, the control member being for example a rotary plug,
• the number of second injection holes of the control member is the same as the number of first injection holes,
• the distribution channel is adapted to be arranged substantially transversely with respect to the flow of the air flow in the intake module,
• the control member is adapted to be arranged substantially transversely with respect to the flow of the air flow in the intake module,
• the control member is in the form of a substantially cylindrical tube, such as a bushel,
• said device comprises at least one return means arranged to bias the control member towards a predefined safety position. It may be for example a return spring.

The invention also relates to an intake manifold for an air intake module configured for supplying at least one cylinder of an internal combustion engine, by an air stream comprising intake gases and / or combustion gases. recirculated exhaust (EGR), characterized in that it comprises at least one recirculated exhaust gas distribution device as defined above.

The invention also relates to an air intake module, such as supercharging air, configured to supply at least one cylinder of an internal combustion engine, by an air flow comprising intake gases and / or or recirculated exhaust gas (EGR), characterized in that it comprises at least one recirculated exhaust gas distribution device as defined above.

According to one embodiment, the air intake module comprises a heat exchanger configured to condition the flow of air, and an intake manifold configured to supply at least one cylinder of the engine arranged downstream of the heat exchanger. according to the flow direction of the air flow in the intake module. The recirculated exhaust gas distribution device is arranged downstream of the heat exchanger, on a portion upstream of the intake manifold, with respect to the direction of flow of the air flow in the intake module.

• la figure 1 montre un module d'admission d'air équipé d'un dispositif de distribution de gaz d'échappement selon l'invention,
• la figure 2 est une vue schématique représentant un collecteur d'admission du module d'admission de la figure 1, comprenant un dispositif de distribution de gaz d'échappement, et
• la figure 3 est une vue en coupe du module d'admission,
• la figure 4 est une vue éclatée du collecteur d'admission et d'un organe rotatif de contrôle des flux de gaz d'échappement, et
• la figure 5 est une vue du module d'admission représentant de façon schématique la connexion fluidique entre l'organe rotatif de contrôle et une canalisation d'acheminement de gaz d'échappement recirculés.

Other advantages and characteristics will appear on reading the description of an illustrative but non-limiting example of the present invention, as well as the appended drawings in which:

• the figure 1 shows an air intake module equipped with an exhaust gas distribution device according to the invention,
• the figure 2 is a schematic view showing an intake manifold of the intake module of the figure 1 , comprising an exhaust gas distribution device, and
• the figure 3 is a sectional view of the intake module,
• the figure 4 is an exploded view of the intake manifold and a rotary member for controlling the flow of exhaust gas, and
• the figure 5 is a view of the intake module schematically showing the fluid connection between the rotary control member and a recirculated exhaust gas channel.

In these figures, the substantially identical elements bear the same references.

We have shown on the figure 1 an intake module 1 intended to be placed on the cylinder head of a multicylinder engine (not shown in the figures) and which comprises for each cylinder of the engine at least one duct intended to extend in the cylinder head to supply the cylinder with gas intake.

The intake module 1 comprises an intake manifold 3, also called distribution manifold, in which opens (s) the (s) supply duct (s) of the engine cylinders.

Since the engine is multi-cylinder, the intake manifold 3 is configured to distribute the flow of intake gas between the ducts respectively associated with a cylinder of the engine according to the illustrated example.

The intake module 1 further comprises an inlet manifold 5 for supplying the intake manifold 3 with inlet gas.

The intake module 1 may comprise a heat exchanger 7 through which the inlet gas from the inlet manifold 5 passes before being distributed in the supply ducts of the different cylinders. The heat exchanger 7 is configured to cool the charge air. Such a heat exchanger 7 is generally called a charge air cooler, known by the abbreviation "RAS". Such a heat exchanger 7 may comprise a bundle of tubes or plates (not shown) delimiting fluid flow channels, such as the coolant, and has at least one inlet and outlet manifold 9 for the coolant.

Subsequently, the terms "upstream" and "downstream" are defined with respect to the direction of circulation of the charge air in the intake module 1. According to the embodiment illustrated in FIG. figure 1 , the charge air is introduced into the heat exchanger 7 through the inlet manifold 5, mounted upstream of the heat exchanger 7, and discharged through the intake manifold 3, also called distribution manifold, mounted in downstream of the heat exchanger 7 and intended to be connected to the cylinder head of the engine (not shown).

Intake manifold

With regard to the intake manifold 3, it allows a distributed admission into the engine cylinders of the intake gases and / or recirculated exhaust gases.

The intake manifold 3 is for example metal and can be mounted on the cylinder head of the engine (not shown).

In order to allow the intake of charge air, possibly cooled, into each of the cylinders of the engine (not shown), the intake manifold 3 comprises at least one outlet channel 10 forming a passage section for the charge air. Here is meant by air fresh air fresh air possibly mixed exhaust gas recovered at the engine output.

According to the illustrated example, the intake manifold 3, mounted downstream of the heat exchanger 7, comprises an open upstream portion on which opens the exit face of the beam of the heat exchanger 7, and a downstream portion intended to be fixed on the cylinder head of the engine. The downstream portion of the intake manifold 3 here comprises the outlet channel (s) 10 arranged to open respectively into the intake cylinders of the engine.

The intake manifold 3 further comprises a distribution device 11 of the recirculated exhaust gas.

According to the illustrated example, the dispensing device 11 is at the level of the upstream portion of the intake manifold 3.

The dispensing device 11 allows injection of the recirculated exhaust gas into the supercharging air stream.

For this purpose, with reference to figure 2 , the distribution device 11 comprises an exhaust gas distribution channel 13 and a first exhaust gas injection means 15, such as at least one first injection hole 15, for putting into fluid communication the distribution channel 13 and the outlet channel (s) 10 for feeding the cylinders.

The distribution channel 13 is arranged on the upstream portion of the intake manifold 3. The distribution channel 13 extends in the example illustrated on the figures 2 and 3 facing the outlet of the heat exchanger 7, substantially transversely to the direction of flow of the charge air.

The distribution channel 13 extends here over the entire width of the intake manifold 3.

It may be a distribution channel 13 of substantially cylindrical shape.

The first or the first injection holes 15 are, for example, made on a wall of the distribution channel 13 downstream with respect to the direction of circulation of the charge air.

According to the illustrated example, the distribution channel 13 comprises a series of first injection holes 15, here four first injection holes 15.

The first injection holes 15 are, for example, substantially circular. They could also be oval or any other suitable forms.

Of course, the intake manifold 3 may have a number of different first injection holes 15. Furthermore, as an alternative embodiment, another shape or dimensions of the first different injection holes 15 may be provided.

The dispensing device 11 further comprises a control member 17 configured to modulate the recirculated exhaust gas stream which is injected by the first injection means 15.

To do this, the control member 17 is here shaped so as to vary the dimensions of the first injection holes 15. In particular, in the case of first injection holes 15 of substantially circular shape, the control 17 is shaped to adjust the diameter of the first injection holes 15.

The dimensions, in particular the diameter, of the first injection holes 15 are related to the engine speed. In other words, the control member makes it possible to adjust the dimensions of the first injection holes 15 as a function of the engine speed.

The control member 17 may be driven by an actuator 18 which may be electrical or alternatively pneumatic. With the aid of an electric actuator 18, it is possible to provide a continuous fine adjustment of the position, for example angular, of the control member 17 with a very small amplitude of movement. With the aid of a pneumatic actuator 18, it is possible, for example, to provide a predefined number of angular positions of the control member 17.

Alternatively, the control member 17 may be driven by the motor shaft.

Moreover, in order to avoid fouling of the distribution device 11, it is possible to rapidly and repeatedly actuate the control member 17 so as to remove the pollutants.

This is for example a rotary control member 17. It is therefore according to the angular position of the rotary control member 17 that the dimensions of the first injection holes 15 can be adjusted.

According to an alternative not shown, the control member 17 is movable in translation. By way of example, it is possible to provide a movable control flap in translation such as a guillotine type flap.

According to the embodiment illustrated on the figures 2 and 3 , the control member 17 is made in the form of a substantially cylindrical rotary tube called plug. We could alternatively provide a rotary control member such as a rotary flap, for example a butterfly-type flap.

The plug 17 is configured to rotate about its longitudinal axis.

The plug 17 is adapted to be arranged so that its longitudinal axis is arranged substantially transversely to the direction of flow of the charge air.

The plug 17 is arranged in the distribution channel 13 so as to extend facing the outlet of the heat exchanger 7, substantially transversely to the direction of flow of the charge air. The plug 17 may extend over the entire length of the distribution channel 13 and thus here over the entire width of the intake manifold 3.

Referring again to the figure 2 , the plug 17 here comprises a port 19 for entering the exhaust gas recirculated into the plug 17. The introduction of the exhaust gas into the plug 17 is shown schematically by the arrow EGR on the figure 2 .

The plug 17 is shaped so as to allow or block the circulation of the recirculated exhaust gas, but also to modulate the flow of exhaust gas, in particular by adjusting the passage section of the first injection holes 15, depending on the angular position of the bushel 17.

For this purpose, the plug 17 comprises a second injection means 21, such as at least one second injection hole 21.

The second injection means 21 is shaped so as to make it possible to vary / adjust the flow section of the flow of exhaust gas recirculated by the first injection means 15.

According to the illustrated embodiment, the plug 17 comprises a series of second injection holes 21, more precisely of the same number as the first injection holes 15, here four.

According to the embodiment illustrated on the figures 2 and 4 , the plug 17 has on the same side the series of second injection holes 21, four holes according to the illustrated example.

The second injection holes 21 allow, when they are at least partially vis-à-vis the first injection holes 15, the injection of the exhaust gas into the supercharging air stream.

Indeed, the plug 17 is adapted to be arranged in a position allowing fluid communication between a first injection hole 15 and a second injection hole 21 associated.

More specifically, each second injection hole 21 is arranged on the plug 17 so as to be aligned with a first associated injection hole 15 as a function of the position of the plug 17, as illustrated in FIG. figures 2 and 3 , that is to say, so that the first and second holes 15, 21 associated injection are vis-à-vis allowing the passage of an exhaust gas flow. When a second injection hole 21 is aligned with a first associated injection hole 15 the passage is maximum for the recirculated exhaust gas stream.

According to the example shown on the figure 4 the second injection holes 21 have a substantially circular shape.

Of course, the number of second injection holes 21 may vary. It is also possible to provide a shape or dimensions of the second different injection holes. It is also possible to provide a different distribution of the second injection holes 21 on the plug 17. In particular, the second injection holes 21 may not be aligned with respect to each other.

The injection of the exhaust gas is distributed thanks to the distribution of the first injection holes 15 along the distribution channel 13 and the distribution of the second injection holes 21 along the plug 17.

Thus, in the volume of the intake manifold 3 downstream of the plug 17 in the direction of flow of the supercharging air, the intake gases admitted by the upstream face of the intake manifold 3 mix with the gases recirculated exhaust pipe admitted by the dispensing device 11.

The charge air comprising fresh air possibly mixed with recirculated exhaust gas is then distributed in the outlet channels 10 in order to supply the engine cylinders with gas for combustion.

Moreover, referring again to the figure 2 , the dispensing device 11 may furthermore comprise at least one sealing means 23 arranged in such a way as to prevent a flow of recirculated exhaust gas injected via a second injection hole 21 from circulating again to another second injection hole 21 of the plug 17 instead of circulating in the volume of the intake manifold 3 to be directed to the outlet channels 10.

Moreover, according to a non-illustrated embodiment, it is possible to provide at least one return means, such as a return spring, arranged in such a way as to urge the plug 17 towards a predefined safety position, for example in the event of a malfunction. of the actuator 18. By way of non-limiting example, this predefined position may be such that the second injection holes 21 of the plug 17 coincide with the first injection holes 15 of the distribution channel 13 or, on the contrary, such that the second injection holes 21 of the plug 17 are not aligned with the first injection holes 15 of the distribution channel 13.

Thus, the distribution device 11 allows an active distribution of the recirculated exhaust gas, in other words allows active adaptation of the exhaust gas streams recirculated by the first injection means 15, according to the flow rate of the recirculated exhaust gas. arriving at the gas inlet 9.

Indeed, with such a dispensing device 11, the passage section of the recirculated exhaust gas flow can be adjusted according to the speed or flow rate of the recirculated exhaust gas.

By way of illustrative and non-limiting example, in the case of a low flow rate of the recirculated exhaust gas, the passage section for the gas defined by the first injection hole 15 closest to the gas inlet orifice 19 may be decreased so as to force the exhaust gas towards the other first injection holes 15 farther from the gas inlet port 19. In other words, in the case of low flow of the recirculated exhaust gas, the first injection hole 15 must have a smaller diameter relative to the other first injection holes 15. To do this, in the case of a rotary plug 17, the plug 17 is rotated to a corresponding angular position.

On the contrary, in the case of a high flow rate of the recirculated exhaust gas, the first injection hole 15 closest to the gas inlet port 19 may be bypassed, the exhaust gas flowing towards the injection holes 15 farther from the gas inlet port 19. In this case, the passage section for the gas defined by the first injection hole 15 closest to the gas inlet port 19 can be increased so as to force the passage of the exhaust gas through this first injection hole 15 closest to the gas inlet port 19. In other words, in case of high exhaust gas flow rate recirculated, the first injection hole 15 must have a larger diameter relative to the other first injection holes 15. To do this, in the case of a rotary plug 17, the plug 17 is rotated to a corresponding angular position .

By thus modulating the passage section of the exhaust gas flow, it is possible to obtain an exhaust gas rate in the cylinders which is satisfactory for several operating points of the engine.

A computer in the vehicle can for example detect the flow rate of the recirculated exhaust gas and send a corresponding instruction to the actuator 18 to drive the control member 17 in the appropriate position to vary the diameter of the first injection holes 15.

This gives a recirculated exhaust gas distribution suitable for a range of engine speed, for example of the order of 1250 to 2500 rpm, which is wider than for the solutions of the prior art for passive distribution exhaust gas, that is to say without adaptation of the passage section of the flow of recirculated exhaust gas.

Finally, it is not necessary to provide an interface for connecting the plug 17 to a valve (not shown) for distributing the recirculated exhaust gas in the bushel 17, as is required in the prior art solutions for determining the amount of recirculated exhaust gas to be introduced into the distribution channel 13.

Indeed, such a valve is not mandatory because the metering of the recirculated exhaust gas stream to be injected into the supercharging air stream can be done directly by the distribution device 11.

Thus, as shown schematically and simplified on the figure 5 , the distribution device 11 can be connected directly to an exhaust gas routing pipe 25 recovered at the motor output.

Claims (12)

Apparatus (11) for distributing recirculated exhaust gas from an intake manifold (3) for an air intake module (1) configured to supply at least one cylinder of an internal combustion engine with a flow of air comprising inlet gases and / or recirculated exhaust gas (EGR), the distribution device (11) comprising a recirculated exhaust gas distribution channel (13), the distribution channel (13) ) comprising a first injection means (15) of recirculated exhaust gas in the air stream for supplying at least one cylinder, characterized in that the dispensing device (11) further comprises a control member (17) ) arranged in the distribution channel (13) and configured to modulate the flow of recirculated exhaust gas injected by the first injection means (15). Device according to claim 1, wherein the control member (17) is rotatable and is configured to modulate the flow of recirculated exhaust gas according to the angular position of the rotary control member (17). Device according to claim 1, wherein the control member (17) is movable in translation. Apparatus according to any one of the preceding claims, wherein the first injection means (15) comprises at least a first injection hole (15) and wherein the control member (17) is shaped to adjust the dimensions of the first injection hole (15). Device according to the preceding claim, wherein: the control member (17) comprises a second recirculated exhaust gas injection means comprising at least a second injection hole (21), and - The control member (17) is adapted to be arranged in a position for the setting in fluid communication between a first injection hole (15) and a second injection hole (21) associated. Device according to the preceding claim, wherein the number of second injection holes (21) of the control member (17) is the same as the number of first injection holes (15). Device according to any one of the preceding claims, in which the distribution channel (13) and / or the control member (17) is capable of being arranged substantially transversely with respect to the flow of the air flow in the intake module (1). Device according to any one of the preceding claims, wherein the control member (17) is in the form of a substantially cylindrical tube. Device according to any one of the preceding claims, comprising at least one return means arranged to bias the control member towards a predefined safety position. Intake manifold (3) of an air intake module configured to supply at least one cylinder of an internal combustion engine, by a flow of air comprising intake gases and / or exhaust gases recirculated (EGR), characterized in that it comprises at least one recirculated exhaust gas distribution device (11) according to any one of claims 1 to 9. An intake module (1) of air, configured to supply at least one cylinder of an internal combustion engine, with a flow of air, such as charge air, comprising intake gases and / or recirculated exhaust gas (EGR), characterized in that it comprises at least one recirculated exhaust gas distribution device (11) according to any one of claims 1 to 9. Air intake module (1) according to the preceding claim, - including: A heat exchanger (7) configured to condition the flow of air, and An intake manifold (3) configured to supply at least one cylinder of the engine, arranged downstream of the heat exchanger (7) in the direction of flow of the air flow in the intake module (1) , and - in which the recirculated exhaust gas distribution device (11) is arranged downstream of the heat exchanger (7), on a part upstream of the intake manifold (3), with respect to the direction of flow of the air flow in the intake module (1).

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