BLOW-BY GAS INTAKE DEVICE AT THE INLET OF A CYLINDER HEAD WITH DEFLECTORS

Description

Technical field of the invention

[0001] The present invention relates to a thermal or internal combustion engine for a motor vehicle.

[0002] The present invention also relates to an intake line of the heat engine.

[0003] The present invention relates more particularly to an intake gas circulation line comprising gases originating from oil vapors or de-oiled. State of the art

[0004] A thermal or internal combustion engine of a motor vehicle has an intake face to which fresh air supply devices are fixed to be injected into the engine and an exhaust face arranged on an opposite side to which other exhaust devices of an exhaust line are fixed to convey burnt gases to pollution control systems and to the outside of the engine. The two faces are longitudinal and symmetrically opposed to each other with respect to a vertical median plane of the engine extending longitudinally.

[0005] As is well known, to reduce pollutant emissions, internal combustion engines are equipped with a recirculation line for burnt gases and gases from oil vapors or de-oiled gases. These gases are returned to the engine intake to be mixed with fresh air before being injected into the engine's air intake circuit. De-oiled gases are also called blow-by gases in English.

[0006] Recirculated gases are of two types: The so-called high-pressure recirculated gases are taken directly from the engine exhaust outlet, for example from a chamber dug into the cylinder head or from an exhaust manifold attached to said cylinder head. The so-called low-pressure recirculated gases are taken further downstream depending on the direction of gas flow and in particular at or downstream of a burnt gas pollution control device such as a catalyst or a NOx or nitrogen oxide trap.

[0007] De-oiled gases refer to gases from oil vapors that pass through an oil decanter attached to the engine, generally at a high point in the engine, at the cylinder head

[0008] The recirculated burnt gases are generally mixed with fresh air which can be compressed following passage through a compression stage, in a known manner upstream of an intake manifold.

[0009] The deoiled gases can be injected into the fresh air flow, generally in a plenum of the intake manifold or directly into the intake ducts of the cylinder head through channels dug into the said cylinder head.

[0010] Publications EP1447533A1 or JP2001140713A thus propose an injection of gases from oil vapors through channels dug into the cylinder head from a gas decanter located in the upper part of the engine on the cylinder head.

[0011] The invention relates to an injection of gases from oil vapors into the intake of a heat engine. The invention relates to a particular implementation of the inlet duct for the deoiled gases downstream of the decanter in the direction of flow of said gases, said duct is dug into the cylinder head to open from the intake face of the cylinder head near the intake distributor.

[0012] Drilling a channel in the cylinder head capable of directing gases from oil vapors into the intake ducts of the cylinder head involves having material around said channel, which results in a larger footprint of the cylinder head and an increase in the mass of said cylinder head.

[0013] There is also known an intake rail for de-oiled gases connected to the distributor and which extends along an axis parallel to the axis of the crankshaft or the engine, said rail is extended by injection channels substantially transverse to the rail to open into the plenum of the intake distributor.

[0014] A disadvantage is the formation of the injection channels which requires material, particularly at the level of a fixing flange or the distributor and which complicates the production of the de-oiled gas intake rail.

[0015] The aim of the invention is to remedy these problems and one of the objects of the invention is an intake device for a motor vehicle thermal engine comprising a cylinder head and an intake distributor fixed against a fixing wall of the cylinder head, said distributor and said cylinder head being shaped to delimit an intake plenum covered by the distributor. Presentation of the invention

[0016] The present invention relates more particularly to an intake device for a motor vehicle thermal engine comprising a cylinder head and an intake distributor fixed by a fixing system comprising a distributor fixing bracket, against a fixing wall of the cylinder head, said distributor and said cylinder head being shaped to delimit an intake plenum covered by the distributor, characterized in that the fixing system comprises a channel for distributing gases from oil vapors, comprising a notch hollowed out at the edge of the distributor between the distributor and the cylinder head in the lower part of the plenum and opening into the plenum, extending over the width of the plenum, transversely to the air flow axis.

[0017] Advantageously, the distribution channel for the de-oiled gases comprises a notch which extends over the width of the plenum for good distribution of said gases and to facilitate obtaining said channel. Said notch is hollowed out at the edge of the distributor in contact with the cylinder head to be close to the intake ducts of the cylinder head. The notch opens into the plenum to facilitate the admission of the de-oiled gases into the plenum.

[0018] According to other characteristics of the invention: the notch has a cross section decreasing from the upstream part to the downstream part according to the direction of circulation of the de-oiled gases.

[0019] Advantageously, the notch has a cross section decreasing from the upstream part to the downstream part according to the direction of flow of the gases in order to control the distribution of de-oiled gases in the intake ducts of the cylinder head and accelerate the flow of the gases. the notch includes a ramp arranged at the bottom of the notch.

[0020] Advantageously, the notch includes a ramp at the bottom of the notch which allows the speed of the de-oiled gases to be accelerated and directed towards the plenum. the ramp has an increasing slope from upstream to downstream to bring the bottom of the downstream end of the plenum notch closer.

[0021] Advantageously, the slope of the ramp is substantially continuous to allow the flow of de-oiled gases and runoff of condensates to be directed. the distribution channel includes deflectors arranged at the edge of the notch to direct the gases along the notch.

[0022] Advantageously, the distribution channel includes a set of deflectors to direct the de-oiled gases along the notch and thus control diffusions in the plenum. the distribution channel has an upstream deflector capable of directing the gases along the notch.

[0023] Advantageously, the distribution channel comprises an upstream deflector capable of directing the gases along the notch in the axis of said notch. The purpose of this first deflector is to direct the gas flow from the outlet of the gases in the distribution channel towards the notch and in particular along the axis of the notch. the notch comprises at least one retaining deflector arranged at the edge of the plenum.

[0024] Advantageously, the notch comprises at least one retaining deflector arranged at the edge of the plenum and capable on the one hand of directing a portion of the gases towards dedicated intake ducts of the cylinder head and on the other hand of retaining a portion of said gases in the notch. The deflectors are preferably arranged at the level of the lower surface of the plenum. the at least one retaining deflector has the shape of an inclined plate which converges towards the bottom of the notch according to the direction of gas flow.

[0025] Advantageously, the plate forming the at least one holding deflector is inclined and converges towards the bottom of the notch in the direction of flow of the gases and in particular towards the ramp in order on the one hand to reduce the pressure losses when the gases pass through said at least one holding deflector and on the other hand to create a convergent to significantly increase the flow speed of said gases. the notch comprises a downstream deflector at the downstream end of the notch arranged at the bottom of the notch.

[0026] Advantageously, the notch comprises a downstream deflector arranged at the downstream end of the notch in the direction of gas flow and at the bottom of the notch in order to direct the remaining gas towards the plenum. the device comprises an outlet of a gas supply conduit emerging from the fixing wall of the cylinder head.

[0027] Advantageously, the intake device may comprise an outlet for de-oiled gases emerging from the cylinder head mounting wall to optimize the size of the engine and to facilitate the intake device. the distributor includes a gas supply duct whose axis is parallel to the fixing sidewalk.

[0028] Advantageously, the distributor may comprise a gas supply duct whose axis is parallel to the fixing sidewalk and which opens substantially directly into the notch, which reduces pressure losses. the fixing sidewalk includes a gas receiving depression.

[0029] Advantageously, the fixing sidewalk comprises a gas receiving depression. Said depression is connected with the distribution channel.

[0030] It is designed opposite the outlet of the gas supply duct, the cylinder head mounting wall to optimally bring the gases to the distribution channel. Brief description of the figures

[0031] Other characteristics and advantages of the invention will appear on reading the following description of particular embodiments of the invention given as non-limiting examples and represented in the appended drawings, in which: [ Fig. 1 ] is a schematic view of an intake face of a cylinder head of a thermal engine according to the state of the art. [ Fig. 2 ] is a schematic view of a cylinder head mounting wall for an intake manifold according to the invention. Fig.3 ] is a schematic view of an intake manifold according to the invention. [ Fig4 ] is a front view of the fixing wall of the distributor with a deoiled gas distribution channel according to the invention. Fig5 ] is a front view of the fixing wall of the distributor with a deoiled gas distribution channel according to the invention. Fig.6 ] is a schematic cross-sectional view of the intake device according to the invention. [ Fig.7 ] is a schematic view of the deoiled gas flows circulating in the distribution channel according to the invention. [ Fig.8 ] is a face of the fixing wall of the distributor with a deoiled gas distribution channel according to another embodiment of the invention.

[0032] In the following description, identical reference numerals designate identical parts or parts having similar functions.

[0033] As is known, thermal or combustion engines comprise a cylinder head 30 fixed to a cylinder block comprising cylinders in which pistons are mounted which move in a sliding manner along the axis of the cylinder.

[0034] The terms up / down refer to a vertical axis which can be the axis perpendicular to the horizontal plane of the engine. Said horizontal plane can be defined parallel to the joint plane between the cylinder block and the cylinder head.

[0035] The longitudinal axis of the engine is defined as the axis joining the centers of the cylinders on the horizontal plane of the engine.

[0036] The terms upstream / downstream refer to the direction of flow of the intake gases or air.

[0037] The heat engine may include a circuit for re-injecting gases from oil vapors into the intake face of the cylinder head. As shown in the figure 1 , the cylinder head 30 comprises an intake face 31. In said intake face, the cylinder head comprises a fixing wall 32 which can border a depression 33 forming a downstream part 37i of an intake plenum 37. Intake ducts 34 are hollowed out in the cylinder head to connect cylinders of the engine to the plenum 37. Said intake ducts 34 open into the plenum, in particular in the lower part of the depression 33 hollowed out in the cylinder head as shown in the figures 1 et 2 . The axes of the outlets of the intake ducts are substantially on a straight line which is parallel to the longitudinal axis of the engine. The longitudinal axis of the engine can be defined by the axis

[0038] It is known in the state of the art to have a decanter (not shown) to separate from gas vapors resulting from the operation of the engine, still hot gases and oil; said decanter can be arranged at the top of the engine, against the cylinder head for example. The oil obtained can then fall by gravity towards an oil sump by different paths. The gases resulting from oil vapors are called blow-by gases in English or de-oiled gases. They are reintroduced to the engine intake. De-oiled gas conduits can be drilled through the cylinder head from the decanter to the intake plenum. Said de-oiled gas conduits open in the upper part of the plenum by outlets 36. The drilling of the de-oiled gas conduits requires having material in order to maintain a minimum rigidity of the cylinder head.Drilling oil-free gas ducts can lead to a minimum cylinder head mass constraint, which goes against the objectives of reducing the mass of the vehicle and in particular the engine to improve engine consumption and reduce pollutant emissions outside the vehicle.

[0039] There figure 2 represents a cylinder head 30 with the face 31 according to an embodiment of the invention. The cylinder head 30 comprises the depression 33 forming the downstream part 37i composing the plenum 37 for the intake of air and gas into the engine. The cylinder head comprises a fixing wall 38 on which the intake distributor 10 is fixed in support by a fixing ledge 11.

[0040] According to the figure 3 , the intake distributor 10 is according to the invention formed by a fixing flange of a casing 41 surrounding a water-air heat exchanger 40. Said casing comprises an air inlet which has been compressed during passage of a compressor and which can be mixed with recirculated gases from an exhaust circuit of the engine. The compressed air and recirculated gas mixture can be brought to a high temperature and needs to be cooled. The mixture therefore passes through the heat exchanger 40, before entering the engine. Hereinafter, the terms distributor or flange will designate the same part which carries out the two functions.

[0041] The intake device 20 therefore comprises the cylinder head with the depression 33 and the intake distributor 10 fixed to each other by a fixing system comprising the fixing ledge 11 of the distributor 10.

[0042] The fixing sidewalk 11 is fixed in abutment against the fixing wall 32 of the cylinder head 30. Said sidewalk advantageously covers the surface of said fixing wall 32.

[0043] In this example of realization according to the figure 6 , the decanter is not fixed in the upper part of the engine but against a wall of a cylinder block, the cylinder block is in a known manner arranged below the cylinder head.

[0044] The gas supply duct 42 may, for example, extend vertically from the cylinder block to the cylinder head. Said supply duct is preferably hollowed out in the wall of the cylinder block and the cylinder head to obtain a compact engine.

[0045] However, the invention is not limited to engines comprising a decanter arranged in a low position fixed to the cylinder block.

[0046] According to one embodiment, the cylinder head comprises an outlet 39 of the gas supply duct from oil vapors, arranged next to the depression 33 forming the plenum. The axis of the outlet is substantially orthogonal to the fixing wall 38 of the cylinder head. Said outlet 39 is according to the figures 1 et 2 , arranged in the fixing wall 38 which is covered by the flange 10. The outlet 39 is notably surrounded by the sidewalk 11 for fixing the distributor.

[0047] The distributor 10 may comprise an intake cone 13 whose gas passage section at the downstream end in the direction of gas circulation is substantially equal to the passage section of the depression 33 of the cylinder head 30. The internal volume 37t of the diffusion cone and the volume of the depression 33 of the cylinder head form the plenum 37 of the intake device 20. The internal volume 37t of the diffusion cone therefore forms the upstream part of said plenum 37. The diffusion cone is in the shape of a parallelepiped because it is in the extension of the heat exchanger 40.

[0048] According to a preferred embodiment of the invention represented by the figures 3 à 5 , the intake device 20 comprises a distribution channel 14 comprising a notch 15 hollowed out at the edge of the distributor, adjoining the cylinder head. It extends over the width of the plenum, transversely to the air flow axis, that is to say in a substantially horizontal direction, substantially parallel to the longitudinal axis of the engine passing through the centers of the engine cylinders on a horizontal plane, when the distributor is mounted fixed against the fixing wall 32 of the cylinder head 30 of said engine. The notch 15 has an opening mouth 16 transverse to the air flow giving into the intake plenum 37. The notch 15 is here arranged in the lower part of the distributor 10.

[0049] Preferably, the length of the notch is equal to or slightly greater than the distance between the outlets in the plenum of the end intake ducts 34 of the cylinder head, i.e. the distance between two end intake duct outlets along the longitudinal axis of the engine. The distance between the axes of said outlets or preferably the distance between the end points of the edges of the outlets of the end intake ducts along the longitudinal axis of the engine may be taken.

[0050] The width of the notch is of the order of a few mm, for example between 3 and 15 mm.

[0051] According to the embodiment, said depression is intended to come opposite the outlet 39 of the cylinder head when the distributor is fixed in abutment against the cylinder head.

[0052] The notch 15 comprises a ramp 17 which may be flat at the bottom of the notch, the slope of which may be substantially continuous to allow the flow of de-oiled gases and runoff of condensates to be directed. The slope may also have flat levels substantially parallel to the lower wall of the plenum according to another embodiment.

[0053] The slope of the ramp is upward in the direction of flow of the deoiled gases, that is to say that the depth of the notch 15 gradually decreases in the direction of flow of the gases to bring the bottom of the downstream end of the notch 15 closer to the plenum 37.

[0054] At the lower level of the ramp 17, that is to say in the upstream part of the ramp, a small condensate recovery groove 43 can be dug in the fixing sidewalk 11, said condensates can then be treated by another device not described here.

[0055] The distribution channel 14 comprises, according to the invention, a notch having an opening 16 in the plenum 37. In order to control the flow of deoiled gases along the notch, the distribution channel comprises a set of deflectors capable of directing at least a portion of the gases along the axis of the notch. Said deflectors are arranged at the edge of the notch and have an inclination adapted to direct the gases towards the axis of the notch 15 according to the direction of flow of the gases from upstream to downstream indicated by an arrow in figures 4 et 5 .

[0056] The distribution channel 14 comprises an upstream deflector 21 capable of directing the flow of gases along the notch. The purpose of said upstream deflector 21 is to direct the flow of deoiled gases towards the notch 15 from the receiving depression 12. Preferably, said first deflector 15 is an inclined plate substantially parallel to the axis of the ramp 17 of the notch 15, and arranged close to the depression 12.

[0057] The distribution channel 14 comprises at least one deflector 22 called a holding deflector for directing a portion of the gases along the axis of the notch. Said at least one holding deflector 22 are formed by inclined plates substantially at an angle towards the bottom of the notch to form with the ramp 17 a gas passage section with a convergent in the notch 15. Preferably, the at least one holding deflector 22 are arranged at the edge of the opening mouth 16 of the notch 15 opening into the plenum. According to the figures 3 à 5 , each of said at least one holding baffle 22 is arranged slightly downstream of the outlet of an intake duct in a cylinder. If two intake ducts 34 are connected to the same cylinder as shown, the associated at least one holding baffle 22 is arranged slightly downstream of the most downstream intake duct outlet of the two ducts, the term downstream relates to the flow of deoiled gases.

[0058] The distribution channel comprises a downstream deflector 23 arranged on the ramp 17 of the notch 15, said downstream deflector 23 has a curvature facing the plenum 37. The downstream deflector is arranged at the level of the intake duct outlet furthest downstream along the longitudinal axis of the engine and the direction of flow of the deoiled gases. According to the figures 3 et 4 , the downstream deflector 23 is arranged at the downstream end of the ramp 17. The purpose of this downstream deflector is to direct the remaining flow of deoiled gas towards the opening mouth 16 leading into the plenum 37 and then towards the intake duct outlet of the cylinder head.

[0059] Said distributor may comprise a receiving depression 12 in the fixing sidewalk 11, said depression forming a receiving chamber for collecting the gases. Said receiving depression 12 is connected to the distribution channel 14.

[0060] The fixing sidewalk 11 comprises a peripheral groove 19 which surrounds the passage section of the intake cone as well as the distribution channel comprising the notch. The peripheral groove is capable of receiving a sealing gasket 19'.

[0061] The distributor is fixed against the cylinder head, the fixing sidewall 11 of the distributor then rests against the fixing wall 32 of the cylinder head. The notch 15 then forms a groove or a slot dug between the distributor 10 and the cylinder head 30 in the lower part of the plenum 37. Said slot has the opening mouth 16.

[0062] The deoiled gases are directed towards the distribution channel 14. They are directed by the upstream deflector towards the notch 15. The at least one holding deflector then makes it possible to effectively distribute the flow of deoiled gases towards the various intake ducts of the engine. The at least one holding deflector 22 makes it possible to keep a portion of the gas flow flowing in the notch. Indeed, a first portion of the gases tends to penetrate into the plenum 37 and the at least one second deflector makes it possible to keep a second portion of the gas flow continuing to flow along the axis of the notch.

[0063] According to the figure 7 , we see that said deoiled gases can enter the plenum but they are pushed back towards the intake ducts by the intake air flow and also attracted by a depression created by the opening of the intake valves controlling the admission of air into a combustion chamber of the engine.

[0064] At the downstream end of the notch 15, the downstream deflector 23 makes it possible to direct the remaining gas flow towards the plenum with a reduced pressure loss.

[0065] The notch forms a slot or crevice in the wall of the plenum 37 when the distributor 10 is fixed against the cylinder head 30. Condensates and oil can be deposited in the bottom of the notch and flow along the ramp 17 during operation of the engine. By separating the distributor 10 from the cylinder head 30, direct access is then obtained to the de-oiled gas intake ducts. The notch 15 therefore allows easy access to the de-oiled gas intake ducts and therefore simplifies the cleaning of said ducts.

[0066] Preferably, the distributor 10 is obtained from plastic or metal alloy, which makes it easier to obtain the distribution channel and in general the hollows or grooves in the wall of the fixing sidewalk 11 of the distributor.

[0067] The objective is achieved: The intake device 20 according to the invention allows an intake of gases from oil vapors that is easy to implement and inexpensive. The notch 15 can be easily obtained by molding or machining. The deflectors 21, 22, 23 can be attached to the distributor by gluing or welding.

[0068] It goes without saying that the invention is not limited to the embodiments of this socket described above as examples; on the contrary, it encompasses all variants thereof.

[0069] For example, as represented in figure 8, the distribution channel 14 may comprise an inlet conduit 44 for the deoiled gases whose axis is parallel to the plane of the fixing sidewalk 11, said inlet conduit opening directly into the notch 15.

Claims

1. Intake device (20) for a heat engine of a motor vehicle, the device comprising a cylinder head (30) and an intake distributor (10) attached by an attachment system comprising an attachment ledge (11) for attaching the distributor against an attachment wall of the cylinder head, the distributor and the cylinder head being shaped to define an intake plenum (37) covered by the distributor, the device comprising a distribution channel (14) for gas originating from oil vapors, characterized in that the distribution channel comprises a notch (15) hollowed out at the edge of the distributor between the distributor (10) and the cylinder head (30) in the lower part of the plenum (37) and opening into the plenum (37), extending over the width of the plenum, transversely to the air flow axis.

2. Intake device (20) for a heat engine according to claim 1, characterized in that the notch (15) has a cross-sectional passage decreasing from the upstream portion to the downstream portion in the direction of flow of the deoiled gases.

3. Intake device (20) for a heat engine according to claim 1 or 2, characterized in that the notch (15) comprises a ramp (17) arranged at the bottom of the notch.

4. Intake device (20) for a heat engine according to claim 3, characterized in that the ramp (17) slopes upward from upstream to downstream to bring the bottom of the downstream end of the notch (15) closer to the plenum (37).

5. Intake device (20) for a heat engine according to any of claims 1 to 4, characterized in that the distribution channel (14) comprises baffles arranged at the edge of the notch to direct the gases along the notch.

6. Intake device (20) for a heat engine according to any of claims 1 to 5, characterized in that the distribution channel (14) comprises an upstream baffle (21) capable of directing the gases from an inlet for said gases along the axis of the notch (15).

7. Intake device (20) for a heat engine according to any of claims 1 to 6, characterized in that the notch (15) comprises at least one retaining baffle (22) arranged at the edge of the plenum (37).

8. Intake device (20) for a heat engine according to claim 7, characterized in that the at least one retaining baffle (22) has the shape of an inclined plate which converges toward the bottom of the notch in the direction of flow of the gases.

9. Intake device (20) for a heat engine according to any of claims 1 to 8, characterized in that the notch (15) comprises a downstream baffle (23) at the downstream end of the notch, arranged at the bottom of the notch.

10. Intake device (20) for a heat engine according to any of claims 1 to 9, characterized in that the device (20) comprises an opening for a gas supply duct projecting out of the attachment wall of the cylinder head (30).

11. Intake device (20) for a heat engine according to any of claims 1 to 9, characterized in that the distributor (10) comprises a gas inlet duct (44) of which the axis is parallel to the attachment ledge (11).

12. Intake device (20) for a heat engine according to any of claims 1 to 11, characterized in that the attachment ledge (11) of the distributor (10) comprises a gas-receiving recess.

13. Internal combustion engine comprising an intake device according to any of claims 1 to 12.

14. Motor vehicle comprising a heat engine according to claim 13.