EP2260188B1 - Improved-efficiency device for recovering the oil contained in the combustion gases - Google Patents

Abstract

A device for recovering the oil contained in the combustion gas leaving the engine, includes at least one orifice (6) for collecting incoming gas, a flow channel (10) for the incoming gas, at least one gas outlet orifice, a wall (12) closing the flow channel (10), a recovery channel (14) for recovering the oil that deposits on the wall (12), and a separator partition separating the recovery channel (14) from the incoming gas flow channel (10), the flow channel (10) being defined by a first cylinder (16), the oil recovery channel (14) being defined by the first cylinder (16) and by a second cylinder (18) surrounding the first cylinder (16), the separator partition being formed by the first cylinder (16), the wall (12) forming an end wall of the second cylinder (18).

Description

TECHNICAL FIELD AND PRIOR ART

The present invention relates to a device for recovering the oil contained in the combustion gases having an improved efficiency, and to an internal combustion engine comprising such a device.

During the operation of the engine, with internal combustion, it occurs in particular at the piston rings, the axis of the turbocharger bearing and the joints of the valve tails, combustion gas leaks, also called Blow-by gas . These gases are recovered, to be reinjected at the intake and ensure their combustion.

However, these gases are loaded with oil used for lubrication, including the air intake and exhaust system composed of one or more camshafts and valves.

In order to reduce the engine oil consumption and to reduce the pollution of the exhaust gases, the oil carried by the Blow-by gases, as well as that projected by the moving parts of the engine, are largely recovered to be returned in the crankcase, the blow-by gases separated from this oil are returned to the engine intake.

The extraction of oil from the Blow-by gases is obtained by means of a separation device, also called settling tank and generally disposed on the cylinder head cover.

This separation device is formed, for example of one or two chambers having baffles in which flow the gas Blow-by, the drops of oil transported by the gas impact the walls component baffles. These drops then flow by gravity along these walls and are harvested and returned to the oil circuit.

This device may comprise a first chamber in which a first oil recovery is performed, then a second larger chamber in which a second recovery is performed. The doubling of the chambers makes it possible to achieve a better separation efficiency.

The drops of oil are entrained in the separation and recovery device by the Blow-by gases or are projected into the device, for example because of the bubbling of the cam shaft in the oil.

Such a device is for example known from the document GB2441404 . This document indeed describes a device for separating and recovering the Blow-by gas oil in which the Blow-by gases are conveyed into a chamber communicating in its upper part, via baffles, with on the one hand, a blow-by gas outlet opening open in the upper wall of this chamber and, on the other hand, with an oil recovery channel contained in these gases extending vertically in the center of this chamber.

Document is also known US 6,626,163 a separator comprising an oil return duct separated from the gas duct.

The known devices give overall satisfaction.

However, due to the reduction of the space dedicated to the engine compartment and the engine itself of motor vehicles, to enlarge the cabin and / or add new systems, including safety, in the engine compartment, these devices occupy also a space more and more reduced. The Blow-by gas collection section, formed by the intersection of the engine and the recovery device, is then reduced with respect to their flow rate.

The velocity of the gases is then very important in the recovery device, in particular in the first chamber, which has the consequence, when the drops recovered in this first chamber fall by gravity, to re-train these drops by the gas Blow-by. These drops are then divided into fine droplets when they hit the walls of the first chamber. However, these fine droplets are difficult to separate from the Blow-by gases. Indeed, their diameter is small enough that the droplets are driven by the gas without impacting the walls of the recovery device, the gas leaving the device and reinjected into the intake are still loaded with oil, which causes an increase of oil consumption by the engine.

It is therefore an object of the present invention to provide an oil separation / recovery device whose efficiency is improved, while respecting a limited space requirement.

STATEMENT OF THE INVENTION

The purpose stated above is achieved by an oil recovery device contained in the Blow-By gases comprising a first and a second recovery chamber, the first chamber comprising means for recovering the oil ensuring a first separation. between oil and gas Blow-by.

The recovered oil is advantageously reinjected into the engine oil circuit upstream of the first chamber.

Thus, the recovered oil is at least mostly returned to the engine oil circuit without being re-driven by the Blow-by gases.

In other words, there is provided an oil flow channel forming on the walls of the first chamber, when the Bow-by gases strike the walls thereof, which is physically separated from a water channel. Blow-by gas flow exiting directly from the engine.

Particularly advantageously, it is planned to pass the Blow-by gases into a volume of oil, this passage causing a retention of the drops of oil entrained by the gases in the volume of oil. Advantageously, this volume of oil is fed by the recovered oil.

The main subject of the present invention is therefore a device for recovering the oil contained in the combustion gases leaving the engine and going to the engine air inlet comprising at least one inlet gas collection orifice, flow of said incoming gases, an outlet of said combustion gases at least partly discharged from the oil, a wall closing said inlet gas flow channel, an oil recovery channel settling on said wall, a separating partition of said recovery channel and of the inlet gas flow channel, wherein the inlet gas flow channel is defined by a first cylinder, the oil recovery channel being delimited by the first cylinder and a second cylinder surrounding the first cylinder, the partition wall being formed by the first cylinder, the wall forming a bottom of the second cylinder, and a passage being defined between led it melts and an end of the first cylinder facing said bottom.

The wall is advantageously concave and connects continuously to at least a portion of the second cylinder, which ensures a good flow of oil drops.

The recovery device according to the invention may comprise a gutter bordering the gas collection orifice, extending radially outwardly of the first cylinder, a passage being provided between one end of the second cylinder opposite the bottom.

The gutter may, in an alternative embodiment, include drain holes for harvested oil, the drain holes allowing the oil to return to the engine upstream of the gas collection port.

This channel is advantageously capable of containing a volume of oil sufficient to force the combustion gases to pass through this volume, this passage ensuring additional recovery of the oil.

The first and second cylinders may be surrounded by a third cylinder forming an outer wall of a first chamber, said third cylinder being connected to the first cylinder to form the gutter, said device also comprising a second chamber connected to the flow channel of the gas entering through the oil collection channel and the gutter, said main chamber having baffles for the combustion gases and is connected to an engine inlet.

In an exemplary embodiment, the device comprises three first chambers connected in parallel to a single main chamber.

The device advantageously comprises two parts made of plastic material by molding, the first part comprising the first and the third cylinder, a lower bottom of a connecting pipe between the first tank and the main tank, and a lower bottom of the main tank, and a second part comprising the second cylinder, an upper bottom of the connecting pipe, an upper bottom and the baffles of the main reservoir, sealing means being interposed between the two parts.

The present invention also relates to an internal combustion engine comprising a device for recovering the oil contained in the combustion gases leaving the engine and going to the engine air intake according to the present invention, fixed on a cover a cylinder head in leaktight manner, said device being connected to the engine so as to collect the combustion gases leaving the engine and returning the collected oil to said gases, and in such a way as to reinject said gases at the outlet of said device at the inlet of said engine .

BRIEF DESCRIPTION OF THE DRAWINGS

• les figures 1A et 1B sont des vues de dessus en perspective et en plan respectivement, d'un exemple de réalisation d'un dispositif de récupération selon la présente invention dans son ensemble,
• les figures 2A et 2B sont des vues de dessous en perspective et en plan respectivement, du dispositif de récupération des figures 1A et 1B,
• la figure 3 est une vue de dessous identique à celle de la figure 2B, la partie inférieure de la deuxième chambre ayant été retirée,
• la figure 4 est une vue en coupe selon un plan AA du dispositif de la figure 3 selon la présente invention partiellement représenté,
• la figure 5 est une vue agrandie de la figure 4, le dispositif étant en fonctionnement.

The present invention will be better understood with the aid of the description which follows and the attached drawings in which:

• the Figures 1A and 1B are views from above in perspective and in plan respectively, of an exemplary embodiment of a recovery device according to the present invention as a whole,
• the Figures 2A and 2B are bottom views in perspective and in plan respectively, of the device for recovering Figures 1A and 1B ,
• the figure 3 is a bottom view identical to that of the Figure 2B the lower part of the second chamber having been removed,
• the figure 4 is a sectional view along a plane AA of the device of the figure 3 according to the present invention partially shown,
• the figure 5 is an enlarged view of the figure 4 , the device being in operation.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

On the Figures 4 and 5 a sectional view of an exemplary embodiment of a recovery device according to the present invention comprising a first separation / recovery chamber 2 of the oil and a second separation / recovery chamber 4 of the oil can be seen. also designated master bedroom.

In the remainder of the description, we will designate the separation / recovery device by recovery device only.

The recovery device according to the present invention is disposed on a cylinder head cover 8 and comprises at least one opening 6 for capturing the Blow-by gases leaking at the segments. This orifice 6 forms the inlet of the device according to the present invention.

In the example shown on the Figures 1A to 3 , the device comprises three gas collection openings 6, 106, 206 arranged in parallel and ensuring the collection of gases all along the cylinder head cover 8.

Each orifice 6, 106, 206 is connected to a first chamber 2, 102, 202 separate from those of the other orifices, the first three chambers 2, 102, 202 being of similar embodiment, we will describe only one in detail.

The first chamber 2 comprises a first duct 10 for channeling the incoming Blow-by gases, a wall 12 opposite to the collection orifice 6 in the direction of flow of the gases on which the gases are impacted, in particular the drips. oil which is deposited, at least in part, on this wall, and a second conduit 14 for channeling the oil settling on the wall 12 while isolating it from the inflow of gases.

For this, the first conduit is delimited by an inner face of a first cylinder 16 disposed the most inside the device, this first cylinder extending from the capture orifice 6 towards the impact wall 12 The second duct 14 is delimited by an outer face of the first cylinder 16 and an inner face of a second cylinder 18 surrounding the first cylinder, the second cylinder extending from the impact wall 12 forming with it a surface substantially continuous towards the capture port. A third cylinder 19 is provided outside the second cylinder, surrounding it, forming the outer wall of the first chamber 2.

The arrows 20 indicate the path of the gases in the device.

The drops of oil entrained by the gases impact the wall 12 and adhere to them, then, because of gravity, they flow along the second cylinder in the second conduit. These drops are isolated from the incoming gases because of the first cylinder 16.

The gases discharged at least partially from the oil join the main chamber 4 by a connecting pipe 22, previously borrowing a baffle 24 defined by the first 16, the second 18 and the third 19 cylinder.

The impact wall advantageously forms a half-vault thus ensuring a gravity flow outwardly the inner face of the second cylinder 18 and advantageously prevents drop drop vertically in the flow of the incoming gas. Of course, a horizontal wall, or a complete arch-shaped wall, is not outside the scope of the present invention, the vertical drop of oil drops directly in the incoming flow being reduced compared to the devices of the state of the invention. the technique.

In general, the impact wall advantageously has a concave shape connecting with at least a portion of the second cylinder 18 so as to form a continuous surface promoting the flow of drops along this surface.

The cylinders can have any section. In the example shown, the cylinders have a substantially rectangular section.

On the other hand, the three cylinders are advantageously chosen so as to have homothetic sections in order to ensure a uniform collection of oil and gases in the direction of the main chamber 4.

In the example shown, there are physically two rooms connected in series, however it is understood that one could predict not to only one chamber, the means according to the present invention being disposed at the entrance of the chamber and the conventional labyrinth partitions being disposed downstream of the separation means in the direction of gas flow.

The first and third cylinders meet at their lower ends to form a gutter 26, in which the harvested oil is stored.

In the example shown, the channel 26 has holes 28 to allow the evacuation of the oil towards the engine. These holes 28 line the passage of Blow-by gas flow, thus avoiding the harvested oil to be directly re-entrained by the Blow-by gases.

Depending on the size of the holes 28 and the operating speed of the engine, a volume of oil can be stored in the trough 26, while the Blow-by gases during their evacuation towards the main chamber pass through this volume of oil. oil. During this passage, oil still contained in the gas is captured.

It may be provided not to pierce the bottom of the channel 26, thus permanently ensuring the presence of a volume of oil V.

The oil thus decanted in this first chamber will pass into the main body of the decanter in the form of streams or oil packets. The oil in this form is now properly treated by a conventional baffled decanter.

In the example shown, the right side of the inner cylinder is lower than that of the left side. The Blow-by gases then tend to start from the side of the lowest cylinder, since it is the one that has the least pressure loss. The oil recovered, because of the inclination of the vault, will tend to flow to the side where the side of the cylinder is the highest. Thanks to this construction, the risk of bringing the oil into contact with the Blow-by gases is reduced, and therefore also the risk of driving the already separated oil.

We will now explain the operation of the separation device on the present invention.

The Blow-by gases symbolized by the arrows escaping from the engine at the segments are loaded with oil used for lubricating the moving parts of the engine, which pass through the cylinder head cover through the orifice 6 and penetrate into the engine. the first chamber 2, more particularly they flow in the first cylinder 16.

Blow-by gases then strike the half-vault 12, the oil is then deposited on this half-vault in the form of drops.

The drops then flow by gravity along the half-vault 12, then on the inner face of the second cylinder 18 and join the gutter 26.

This oil is then returned to the engine through the drain holes 28.

The Blow-by gases thus partially discharged from the oil also pass between the first 16 and the second 18 cylinder, borrowing the chicane formed by the gutter 26.

If it contains oil, the gases pass through this volume and still discharge some of the oil they carry.

The gases then borrow the passage delimited between the second 18 and the third 19 cylinder, then the connecting conduit 22 and join the main chamber 4. In the main chamber 4, the gases take a series of baffles 23, allowing to unload even more the gases of the remaining oil they carry.

It should be noted that the collection of oil and the flow of gases takes place on the entire periphery of the first chamber 2.

As can be seen in the example shown on the Figures 1A to 3 , the oil recovery device comprises three first chambers 2, 102, 202 in parallel disposed on the cylinder head cover all along thereof. This number is in no way limiting and can be modified according to the characteristics of the engine.

These first three chambers 2, 102, 202 are connected to a single main chamber 4 by a connecting conduit 22, 122, 222 respectively, which can be seen inside on the figure 3 , in particular the multitude of baffles 23 for harvesting the remaining oil.

This main tank 4 comprises an outlet port 30 of Blow-by gases discharged from all or part of the oil provided in an upper part of the tank. main reservoir 4, this orifice 30 comprises a nozzle 32 intended to be connected to the engine inlet, the gases being burned therein, and oil outlet orifices 34 collected at the end of cannulas 36 passing through the cylinder head cover and the bolt, to send it back into the engine.

The oil recovery device is for example made of plastic material, preferably by molding. For this, it is planned to make the device in two parts, a lower part 38 comprising the first 16 and the third 19 cylinder, the bottom bottom of the connecting pipe 22, and the bottom bottom of the main tank 4, and a second part comprising the second cylinder, the upper bottom of the connecting pipe, the upper bottom and the baffles 23 of the main tank 4.

One or more seals 42 are interposed between the first 38 and the second part 40. Seals 44 are also provided between the recovery device and the cylinder head cover, in particular between the bottom of the channel 26 and the cylinder head cover. For example, a groove 46 surrounding the inlet of the gas Blow-by in the first tank 1 is provided in the bottom of the channel 26 outside thereof.

The first and second parts are secured, for example by melting the plastic material or by snapping.

The embodiment by molding reduces the production costs of the device. The device can be made for example of polyamide, polypropylene with or without glass fibers.

We have made a device for recovering the oil contained in the Blow-by gases to avoid a direct retraining of the oil collected by the gases entering the device, avoiding the formation of fine droplets difficult to separate from the flow gas.

Claims (9)

1. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine including at least one collector orifice (6, 106, 206) for incoming gas, a flow channel (10) for said incoming gas, an outlet orifice (30) for said combustion gas that has been at least partially de-oiled, a wall (12) closing said flow channel (10) for the incoming gas, a recovery channel (14) for recovering the oil that becomes deposited on said wall, and a partition separating said recovery channel (14) from the incoming gas flow channel (10), characterized in that the incoming gas flow channel (10) is defined by a first cylinder (16), the oil recovery channel (14) is defined by the first cylinder (16) and by a second cylinder (18) surrounding the first cylinder (16), the separation partition being formed by the first cylinder (16), the wall (12) forming an end wall of the second cylinder (18), and a passage being defined between said end wall and one end of the first cylinder (16) facing said end wall.
2. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to claim 1, wherein the wall (12) is concave and connects continuously with at least a portion of the second cylinder (18).
3. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to claim 1 or claim 2, the device including a gutter (26) surrounding the collector orifice (6), extending radially outwards from the first cylinder (16), a passage being provided relative to an end of the second cylinder (18) that is remote from the end wall.
4. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to the preceding claim, wherein the gutter (26) includes drain holes (28) for the collected oil, the drain holes (28) enabling the oil to return to the engine upstream from the gas collector orifice (6).
5. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to claim 3 or claim 4, wherein the gutter (26) is suitable for containing a volume of oil (V) that is sufficient to constrain the combustion gas to pass through said volume (V).
6. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to any one of claims 3 to 5, wherein the first and second cylinders (16, 18) are surrounded by a third cylinder (19) forming an outer wall of a first chamber (2), said third cylinder (19) being connected to the first cylinder (16) to form the gutter (26), said device also including a second chamber (4) connected to the incoming gas flow channel (10) by the oil collector channel (14) and the gutter, said main chamber (4) including baffles (23) for the combustion gas and being connected to an admission of the engine.
7. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to claim 6, the device including three first chambers (2, 102, 202) connected in parallel to a single main chamber (4).
8. A device for recovering the oil contained in the combustion gas leaving an engine and traveling to the air admission of the engine according to claim 6 or claim 7, the device comprising two parts (38, 40) made by molding a plastics material, the first part (38) including the first and third cylinders (16, 19), a bottom of a link duct (22) between the first tank (2) and the main tank (4), and a bottom of the main tank (4), and a second part (40) comprising the second cylinder (18), a top of the link duct (22), a top and the baffles (23) of the main tank (4), sealing means (42) being interposed between the two parts (38, 40).
9. An internal combustion engine including a device according to any preceding claim for recovering the oil contained in the combustion gas leaving the engine and traveling to the air admission of the engine, the device being fastened on a cylinder-head cover (8) in sealed manner, said device being connected to the engine in such a manner as to collect the combustion gas leaving the engine and return the oil collected from said gas, and in such a manner as to reinject said gas at the outlet from said device to the admission of said engine.

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