FR3062684A1 - CYLINDER HEAD COMPRISING AN EXHAUST GAS INJECTION ASSEMBLY - Google Patents

Abstract

The invention relates to a cylinder head (31) for an internal combustion engine having at least one cylinder, comprising a compressed fresh air filling chamber (19) and an exhaust gas injection assembly (1) comprising a chamber recirculated gas filling device (16). According to the invention, the recirculated gas filling chamber (16) is arranged in the cylinder head (31) and connected to gas intake ducts (5) in the at least one cylinder by at least one injection channel (11).

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,062,684 (to be used only for reproduction orders)

©) National registration number: 17 51007

COURBEVOIE © Int Cl ⁸ : F 02 F1 / 24 (2017.01), F 02 F 1/42, F 02 M 26/17

A1 PATENT APPLICATION

©) Date of filing: 07.02.17. (© Applicant (s): RENAULT S.A.S. Joint-stock company (© Priority: simplified - FR. @ Inventor (s): CHALMETTE BRUNO and JALADE MATTHEW. (43) Date of public availability of the request: 10.08.18 Bulletin 18/32. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ©) Holder (s): RENAULT S.A.S. Joint-stock company related: simplified. ©) Extension request (s): © Agent (s): RENAULT SAS.

CYLINDER HEAD COMPRISING AN EXHAUST GAS INJECTION ASSEMBLY.

FR 3 062 684 - A1 (5 /? The invention relates to a cylinder head (31) for an internal combustion engine having at least one cylinder, comprising a chamber for filling with compressed fresh air (19) and an injection assembly ( 1) of exhaust gas comprising a recirculated gas filling chamber (16).

According to the invention, the recirculated gas filling chamber (16) is arranged in the cylinder head (31) and connected to gas inlet conduits (5) in the at least one cylinder by at least one injection channel (11).

CYLINDER HEAD COMPRISING A GAS INJECTION KIT

EXHAUST

The present invention stands î report has a engine at combustion internal with a system of recirculation of gas exhaust. This system, often called by her

English name "Exhaust Gas Recirculation" (EGR), allows to reduce polluting emissions, in particular of nitrogen oxides (NOx). More particularly, the invention relates to a cylinder head and an exhaust gas injection assembly forming part of the recirculation system.

Conventionally, on combustion engines, and in particular diesel engines, the exhaust gas recirculation system (EGR) is installed to take a part of the burnt gases from the engine exhaust and introduce them into the ducts d intake of the engine by mixing them with fresh compressed air from the outlet of a compressor which may be the compressor of a turbocharger. Said compressed fresh air can then pass via a cooler to be brought to the intake ducts by an intake manifold fixed against the cylinder head.

Depending on where the exhaust gases are taken from, there are different EGR gas diffusion systems, one of which recovers part of the exhaust gas just after the exhaust manifold. These gases are still very hot and therefore under high pressure, hence the name EGR High Pressure system (EGR HP).

The HP EGR system typically includes a delivery conduit and an exhaust gas injection assembly. The routing conduit allows exhaust gases from the exhaust manifold to the intake side of the engine. Then, the exhaust gases are injected at the intake distributor, placed upstream of the intake ducts, by means of the injection system.

Thus, the recirculated exhaust gas is mixed with fresh air in a mixing zone of the intake manifold. This mixing zone is otherwise called “plenum” according to the vocabulary of a person skilled in the art.

There are known structures of different EGR-HP diffusion systems but integrated into the intake manifold. A first structure, in the form of a nozzle, introduces recirculated exhaust gases into the intake distributor, via the injection assembly comprising an intrusive connection (or nozzle) in the air intake stream. However, the injection assembly of such a structure is not very efficient and presents a problem of homogeneous distribution of the recirculated gases injected from one cylinder to another and significant pressure losses at the intake circuit. air.

A second EGR-HP structure includes an injection assembly which consists of a distribution rail integrated into the intake manifold. However, this structure has a drawback in that the injection assembly, being integrated into the distributor, increases the weight of the latter and the size of said distributor thereby impacting the space available in the engine compartment which is the space of the vehicle where the engine is housed with its accessories.

Thus, an objective of the invention is to provide an internal combustion engine comprising an exhaust gas injection assembly having a compact structure. Another object of the invention is to propose an exhaust gas injection assembly which does not burden the intake distributor and which simplifies this distributor.

To this end, the invention provides a cylinder head for an internal combustion engine having at least one cylinder and comprising a chamber for filling with compressed fresh air. The cylinder head further includes an exhaust gas injection assembly having a recirculated gas filling chamber.

According to the invention, the recirculated gas filling chamber is arranged in the cylinder head and connected to gas admission conduits in the at least one cylinder by at least one injection channel.

The at least one injection channel is part of the exhaust gas injection assembly. Thus, all or part of the exhaust gas injection assembly is in the cylinder head. Therefore, the integrated injection assembly is therefore less conventional devices.

bulky compared to In addition, the injection assembly is not integrated in the intake manifold, which makes it possible to lighten and simplify the structure of the latter.

According to a particular characteristic of the invention, the filling chamber for recirculated gases is covered by a removable cover.

By way of example, the exhaust gas injection assembly comprises a routing duct connected to the exhaust manifold and to a chamber for filling the recirculated gases arranged in the cylinder head. Said recirculated gas filling chamber has a wall hollowed out in the cylinder head.

Thus, each or the injection channel is connected upstream to said filling chamber for recirculated gases and downstream to a mixing zone between fresh compressed air and recirculated gases. Thanks to the removable cover, the interior of the or each injection channel is easily accessible to an operator to allow cleaning of the injection assembly in the event of fouling and limit the labor cost for the maintenance of the injection assembly. In fact, during the operation of the engine, there may be a more or less significant deposit of soot and hydrocarbon particles, carried by the exhaust gases, in the recirculation system, and in particular in the assembly d 'injection. This phenomenon, called fouling, reduces the performance of the recirculation system and cleaning of the system may be necessary. Unlike the or each injection channel of the invention, in the case of an injection assembly integrated into the distributor, it is necessary to dismantle the distributor from the cylinder head and clean the distribution rail which is sometimes not easy to achieve, even unreachable. In this case, in the event of a malfunction, we are forced to replace the entire distributor, which is expensive in terms of labor and warranty cost.

According to another characteristic of the invention, the filling chamber for the recirculated gases is separated from the compressed air filling chamber. The term “separate” means that the filling chambers for recirculated gases and compressed air are delimited by at least one wall of material arranged between the two chambers.

The separation of the recirculated gas filling chamber from the compressed air filling chamber makes it possible to restrict pollution of the recirculated gases to the recirculated gas filling zone without touching the compressed air filling chamber.

According to one embodiment of the invention, the cylinder head comprising intake ducts which are distributed in a first direction, the exhaust gas injection assembly comprises the injection channel or several injection channels distributed (s) following said first direction. Thus, the exhaust gases introduced into the or each of these injection channels are distributed homogeneously in a mixing zone located upstream of each intake duct. Consequently, the intake ducts receive exhaust gases in equal parts, which ensures an identical quality of combustion for each of the engine cylinders, into which the intake ducts open.

According to one embodiment of the invention, a cylinder is connected to the filling chamber for the recirculated gases by a single injection channel.

According to a characteristic of the invention, the number of injection channels corresponds to the number of cylinders of the engine. Said injection channels are connected to the intake conduits. Thus, the intake ducts are supplied with exhaust gas to optimize pollution control.

According to a characteristic of the invention, the recirculated gases and the fresh air are mixed in a mixing zone arranged upstream of the intake ducts.

In this way, the compressed air coming from a compression system which can be the compressor part of a turbocharger is mixed with the recirculated gases only in a mixing zone arranged near the upstream of the intake ducts of the cylinder head. , said recirculated gases are led from the filling chamber of the recirculated gases to said mixing zone by the injection channels which make it possible to preserve the cooler from pollution caused by the recirculated gases in the event of said gases flowing back from the cylinder head.

For example, the mixing zone is placed immediately in front of the inlet of the intake ducts. Alternatively, the mixing zone can be a part of the intake duct: the injection channel for the recirculated gases can indeed open into said intake duct. Thus, the time required to move the exhaust gases to the interior of the intake ducts is reduced.

According to one embodiment of the invention, the exhaust gas injection assembly comprises the at least one injection channel opening into the mixing zone on the one hand and communicating with the gas filling chamber d on the other hand.

According to a characteristic of the invention, the removable cover covers an opening opening into the recirculated gas filling chamber.

According to one embodiment of the invention, the opening opening into the recirculated gas filling chamber is made on a part of the or each injection channel which is located inside the cylinder head. Thus, access to the injection channel is further facilitated.

According to one embodiment of the invention, the removable cover has a curved profile defining a volume V for filling the exhaust gas. In other words, the removable cover has a domed shape which delimits a volume V into which the exhaust gases are supplied. Thus, one can modify the shape of the hood so that it can contain a desired volume of exhaust gas. This conditions the quantity of gas sent to each of the intake ducts and therefore the depollution efficiency in each of these ducts.

Alternatively, the removable cover includes a flat plate for guiding the recirculated gases.

The invention also relates to an internal combustion engine comprising a cylinder head having one of the characteristics presented above. The invention further relates to a motor vehicle comprising said internal combustion engine.

Other characteristics and innovative advantages will emerge from the description below, provided for information and in no way limitative, with reference to the appended drawings, in which:

- Figure 1 shows a perspective view of a cylinder head according to a first embodiment of the invention comprising an exhaust gas injection assembly and an intake manifold;

- Figure 2 shows the same view as Figure 1 but in the absence of the intake manifold;

- Figure 3 shows a sectional view along the plane III-III illustrated in Figure 1;

- Figure 4 shows a perspective view of a cylinder head according to a second embodiment of the invention comprising an exhaust gas injection assembly and an intake manifold;

- Figure 5 shows the same view as Figure 4 but in the absence of the intake manifold;

- Figure 6 shows a rear view of the cylinder head of Figure 4;

- Figure 7 shows a sectional view along the plane VII-VII illustrated in Figure 6.

Referring to Figure 1 and Figure 2, an intake manifold 41 is connected to a cylinder head 31 on the intake side thereof. A removable cover 13 is located above the intake distributor 31. This removable cover 13 delimits a recirculated gas filling chamber 16 hollowed out in the cylinder head 31 and connected with an inlet 12 for exhaust gas. These elements belong to an exhaust gas injection assembly 1 according to the invention, called in shorthand below the injection assembly.

The exhaust gas inlet 12 is connected to a routing conduit (not illustrated in the figures) which makes it possible to bring exhaust gases from an exhaust manifold (not shown) to the injection set 1.

In order to facilitate understanding of the example, an orthogonal coordinate system R is defined associated with all of the elements illustrated in FIG. 1. This coordinate system R consists of three axes X, Y and Z perpendicular to one another : the first and second horizontal axes X and Y and the vertical axis Z pointing upwards in FIG. 1. The terms “above”, “below”, “lower”, “upper” are defined relative to the axis vertical Z, the terms "behind", "front" or "front", "rear" are defined relative to the second horizontal axis Y.

With reference to FIG. 2 and to FIG. 3, in a lower compartment 33, the inlets 51 of the intake conduits 5 of the cylinder head 31 are seen. In this example, the engine comprises four cylinders, each of which has two inlets d intake and two exhaust inlets. The intake conduits 5 are distributed along the first horizontal axis X. Here, the lower compartment 33 further comprises a chamber for filling with compressed fresh air 19 which communicates with the enclosure 43 of the intake distributor 41. The chamber for filling with compressed fresh air 19 is also shown in FIG. 3.

In an upper compartment 34, a distribution channel 14 is produced in the cylinder head 31 with its axis L parallel to the first horizontal axis X. The distribution channel 14 is part of the filling chamber for recirculated gases 16 and has an opening 15.

The distribution channel 14 intersects the inlet orifices 110 of the injection gas injection channels 11. The injection channels 11 are distributed along the distribution channel 14. In this example, the injection channels 11 are four in number, the same number as the cylinders.

The removable cover 13, covering the distribution channel 14 and the injection channels 11, defines with the distribution channel 14, the filling chamber for recirculated gases

16. Thus, the volume of this recirculated gas filling chamber 16 is filled with exhaust gases which are then injected into the injection channels 11 shown in FIG. 3.

Here, the recirculated gas filling chamber 16, being located at the level of the upper compartment 34, is separated from the compressed fresh air filling chamber 19.

In FIG. 3, the exhaust gases, along the injection channels 11, arrive in a zone 17 for mixing the exhaust gas and the intake gas. In addition, since the distribution channel 14 extends in the same distribution direction as the intake ducts 5, the exhaust gases are distributed homogeneously in this same direction and are therefore sent upstream of each duct d 'intake 11. The term "upstream of each of these intake ducts" means the location located near the inlets 51 of the intake ducts 5 according to the direction of gas flow.

In this example, the injection channels 11 are inclined relative to the vertical axis Z, in the same direction Y ', so as to have their outlet orifice 18 as close as possible to the inlet 51 of the conduits admission. Here, the mixing zone 17 is located very close, in the immediate vicinity of the inlet 51 of the intake conduits 5.

In the event of fouling of the injection channels 11 illustrated in FIGS. 1 to 3, it suffices to remove the removable cover 13. Thus, an operator, with the appropriate cleaning tools, can reach the interior of the injection 11 through their inlet port 110 to clean them. There is therefore no need to dismantle the intake distributor 41 from the cylinder head and therefore less complex operations to clean the injection assembly according to the first embodiment of the invention.

Figures 4 to 7 show an injection assembly 2 according to a second embodiment of the invention.

An intake distributor 42 is mounted on a cylinder head 32. The distributor 42 may for example include a cooler. As shown in Figures 5 and 7, the cylinder head 32 further comprises an air filling chamber

According to the invention, a single distribution channel conduit for compressed costs 29 which communicates with the intake distributor 42.

The injection assembly 2 comprises a single exhaust gas inlet 22, located above the intake distributor 42. Of course, the location of the exhaust gas inlet 22 may be different in d other embodiments of the invention. The inlet 22 communicates with a distribution channel 14 extending substantially in the horizontal direction X. Said distribution channel 14 is hollowed out in the wall of the cylinder head and has orifices opening out into injection channels 21.

The injection channels extend substantially in the directions Y1, Y2 and Y3, inclined relative to the vertical, towards the intake ducts.

an engine cylinder may have an inlet connected with an allow uniform diffusion of EGR gases in the intake ducts.

Once the exhaust gases are introduced inside the injection assembly 2, they go towards the injection channels 21 integrated in the cylinder head 32. The latter each open near the inlets 51 of the conduits d admission 5.

According to this second embodiment, as illustrated in FIG. 7, each injection channel 21 opens into a mixing zone 27 which is located near the inlet 51 of the intake ducts. They can also lead directly into the intake duct.

Furthermore, each injection channel 21 comprises an opening 25 which is situated inside the cylinder head 32. In the example illustrated, the distribution channel 14 communicates with the injection channels 21 which are each closed by a removable cover 23. The assembly of the distribution channel 14 and the injection channels 21 thus forms a filling chamber for recirculated gases 26. Thus said chamber 26 is separated from the filling chamber for fresh compressed air 29 by said cover removable 23.

The removable cover 23 is for example a flat sheet metal plate which can be screwed to the cylinder head. In this embodiment, the air coming from the intake distributor 42 is guided by the wall of the cover 23. Consequently, it is preferred here to have a flat guide surface to promote the internal air performance of the cylinder head and avoid pressure drops.

In the event of fouling, the operator simply removes the intake distributor 42 and the removable cover 23, in order to be able to access and clean the injection channels 21.

Another advantage of the removable cover 23 according to the second embodiment is to prevent the escape of exhaust gases towards the intake manifold 42, in particular when the latter comprises a cooler. In fact, since the exhaust gases contain harmful and corrosive components, they can damage the cooler by passing through it. For this reason, the removable cover 23 is an effective means for protecting the cooler from the exhaust gases.

According to another exemplary embodiment of the invention, the injection channels 21 can be arranged so as to have their opening 25 located outside the cylinder head 32. In this way, the removable cover 23 will be outside of the cylinder head 32. Thus, it is no longer necessary to dismantle the intake manifold 42 to gain access to the removable cover 23.

Claims (10)

1. Cylinder head (31; 32) for an internal combustion engine having at least one cylinder, comprising a chamber for filling with compressed fresh air (19; 29) and an injection gas injection assembly (1, 2) having a recirculated gas filling chamber (16; 26); said cylinder head (31; 32) being characterized in that the recirculated gas filling chamber (16; 26) is arranged in the cylinder head (31; 32) and connected to gas inlet conduits (5) in the au at least one cylinder by at least one injection channel (11; 21). 2. Cylinder head (31; 32) according to claim 1, characterized in that the recirculated gas filling chamber (16, 26) is covered by a removable cover (13; 23). 3. Cylinder head (31; 32) according to the claim 1 or 2, characterized in this than bedroom of filling gases recirculated (16; 26) East separate from the filling chamber fresh air (19; 29) 4. Cylinder head (31; 32) according to any one of claims 1 to 3 with the intake ducts being distributed in a first direction (X), characterized in that the at least one injection channel (11; 21 ) is distributed to the intake ducts (5) in said first direction (X). 5. Cylinder head (31) according to any one of claims 1 to 4, characterized in that a cylinder is connected to the filling chamber for the recirculated gases (16) by a single injection channel (11). 6. Cylinder head (31; 32) according to one of claims 1 to 5 characterized in that the recirculated gases and the fresh air are mixed in a mixing zone (17; 27) arranged upstream of the intake ducts ( 5). 5 7. Cylinder head (31; 32) according to any one of claims 2 to 6 when claims 3 to 6 depend on claim 2, characterized in that the removable cover (13; 23) covers an opening (15; 25) opening into the recirculated gas filling chamber 10 (16; 26). 8. Cylinder head (31) according to claim 7, characterized in that the removable cover (13) has a curved profile defining a volume V for filling the exhaust gas. 9. Cylinder head (32) according to claim 7, characterized in that the removable cover (23) comprises a flat plate for guiding the recirculated gases. 10. Internal combustion engine characterized in that it comprises a cylinder head (31; 32) according to one of the preceding claims. 11. Motor vehicle characterized in that it comprises an engine according to claim 10. 1/2 Z