Internal combustion engine equipped with an oil separator and at least one lower housing gas exhaust chimney comprising a blade device promoting oil condensation

Abstract

Powertrain comprising an internal combustion engine (1), an air intake circuit (3), a circuit for recycling gases from a lower housing of the engine (5) comprising a pump (5a) directing gases from at least one lower housing gas exhaust chimney (5d) from the lower housing (1b) to an oil separator (5b) connected at the outlet to a clean oil gas line (5c), tapped into the air intake circuit (3), an oil return circuit (7) from the oil separator (5b) to the internal combustion engine (1), and a ventilation line (8) bringing fresh air into the lower housing (1b), characterized in that it comprises a blade device (5e) at the outlet of the lower housing gas exhaust chimney (5d) and upstream of the pump (5a), comprising at least two louvers arranged so that the oil comprised in the lower housing gases condenses at least partially on their surface and flows into the lower housing gas exhaust chimney (5d).

Description

[0001] DESCRIPTION

[0002] TITLE: Internal combustion engine equipped with an oil separator and at least one lower housing gas exhaust chimney comprising a blade device promoting oil condensation.

[0003] Technical field

[0004] The invention relates generally to an architecture for treating gases in an internal combustion engine, in particular gases coming from the lower housing of said engine, called "blow by" gases. It finds a particularly advantageous application in an internal combustion engine of a motor vehicle of the controlled ignition type operating with hydrogen .

[0005] Prior arts

[0006] An internal combustion engine generates during its operation unburned combustion gas leaks from the combustion chambers into a lower housing of the engine, at the piston rings and located under the cylinders.

[0007] These gases contain both unburnt fuel and oil droplets from contact of combustion chamber gases with engine components coated in lubricating oil. These oily gases accumulate in the lower housing and must be evacuated and recycled to the engine.

[0008] In particular, it is necessary to separate the oil droplets from the gases containing unburned fuel, that is to say de-oil the gases, before reintroduction at the engine intake. Indeed, the reintroduction of gases as such would result in pollution of the combustion chambers, as well as significant oil consumption by the engine. In addition , the oil would tend to make the combustion of the mixture in the combustion chambers incomplete and create more pollutant emissions.

[0009] In addition, it is prohibited to release housing gases containing unburned hydrocarbons into the atmosphere, which requires them to be recycled to the engine intake.

[0010] To achieve this, a large number of devices are known from the state of the art for de-oiling the lower housing gases, called "blow-by" gases, and for reintroducing these fuel-laden gases into the intake of the engine, where they contribute to the richness of the air-fuel mixture. The state of the art consists in particular of settling devices arranged outside the engine to treat the combustion gases by separating the oil from the gases.

[0011] However, more particularly on spark-ignition internal combustion engines running on hydrogen, the blow-by gases recirculating in the lower housing of the engine through the segmentation are charged with hydrogen that has not been burned in the combustion chamber at a hydrogen concentration that may exceed the flammability threshold of 4%.

[0012] Unlike conventional fuels (gasoline, alcohol, etc.) where the concentration of the gases in fuel does not pose a particular risk of ignition , in the case of hydrogen, it becomes necessary to lower the concentration.

[0013] To achieve this, it is known to dilute the gases with fresh air through the use of a pump located on the engine's settling circuit, the pump taking clean air from the engine's air intake circuit downstream of the air filter and sending it into the engine's lower housing to dilute the gases there.

[0014] Figures [Fig . 1 ] and [Fig . 2] representing the state of the art for a hydrogen internal combustion engine show an in-line three-cylinder engine referenced 1 , supercharged by a turbocharger referenced 2. In figure [Fig . 2], the engine 1 comprises cylinders 1 a and a lower housing l b and is associated with an air intake circuit referenced 3 and a burnt gas exhaust circuit referenced 4.

[0015] The intake circuit 3 successively comprises an air filter 3a, a hydrogen concentration sensor 3b, the compressor 2a of a turbocharger 2, an air intake valve (or throttle box) referenced 3c and a distributor (or intake manifold) referenced 3d.

[0016] The exhaust circuit 4 successively comprises an exhaust manifold 4a and the turbine 2b of the turbocharger 2 mounted on a shaft common to the compressor 2a and a vent. Depending on the implementation , the exhaust line may optionally comprise emission control devices not shown .

[0017] The circuit for recycling the lower housing gases, known as the "blowby” circuit, comprises an active pump referenced 5a directing gases from at least one chimney for evacuating the lower housing gases, known as the "blow-by” chimney coming from the lower housing 1 b to an oil separator 5b. In figure [Fig. 2] illustrating a cross-sectional view of the internal combustion engine 1 , a chimney 5d connects the lower housing 1 b of the engine with an intermediate housing 3e upstream of the pump 5a. The internal combustion engine 1 is equipped with an oil return circuit 7 allowing the oil decanted in the oil separator 5b to return to the oil layer. Such a circuit is illustrated in figure [Fig . 1 ] and figure [Fig . 2] ,

[0018] The oil separator 5b is connected at the outlet by a clean gas pipe 5c, composed of burnt gases and hydrogen , without oil, tapped into the air intake circuit 3 downstream of the air filter 3a.

[0019] A ventilation line 8 of the lower housing 1 b ("scavenging line") brings fresh air into the lower housing 1 b, sucked in by the pump 5a. The ventilation line 8 is tapped downstream of the air filter 3a and upstream of the clean gas pipe 5c.

[0020] However, with this system , tests have led to the observation of too much hydrogen-laden oil in the combustion gases ("blow-by" gases) rising H2from the lower housing 1 b of the engine through the "blow-by" chimneys to be treated in the settler by means of an air pump.

[0021] The technical problem of decanting oil-laden blow-by gases in a hydrogen-powered internal combustion engine thus remains unresolved.

[0022] Another technical problem is to minimize hydrogen concentration H2for safety reasons.

[0023] Explanation of the invention

[0024] The invention relates to a powertrain comprising an internal combustion engine, an air intake circuit, a circuit for recycling gases from a lower housing of the engine comprising a pump directing gases from at least one chimney for evacuating gases from the lower housing to an oil separator connected at the outlet to a clean oil gas pipe, tapped from the air intake circuit, an oil return circuit allowing the oil decanted in the oil separator to return to the oil layer present in the lower housing of the internal combustion engine located below the cylinders, and a ventilation line tapped upstream of the clean gas line and bringing fresh air into the lower housing , sucked in by the pump. The powertrain comprises a blade device at the outlet of the lower housing gas exhaust chimney and upstream of the pump, the blade device comprising at least two louvers arranged so that the oil comprised in the lower housing gases condenses at least partially on their surface, and flows in the lower housing gas exhaust chimney to the internal combustion engine.

[0025] The blade device may comprise a base to which at least two louvers are attached by a first proximal end.

[0026] The base may be provided with domed buttons, an upper domed button being attached to a second distal end of the louvers, the domed buttons and the upper domed button allowing the blade device to be positioned in the lower housing gas exhaust chimney.

[0027] At least part of the louvers may be extended by a blade forming an inclination with respect to the base different from the inclination of the louvers with respect to the base.

[0028] The base may be provided with domed buttons, all the blades being connected in pairs by means of a pin , the blade furthest from the base then supporting an upper domed button , the domed buttons and the upper domed button allowing the blade device to be positioned in the lower gas exhaust chimney.

[0029] The internal combustion engine can run at least partially on dihydrogen.

[0030] The exhaust line may comprise at least one emission control device.

[0031] The blade device has the advantage of a particularly low cost, especially in view of the advantage generated, and is applicable to all internal combustion engines.

[0032] Brief description of the drawings

[0033] Other aims, characteristics and advantages of the invention will become apparent on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which :

[0034] - Figure [Fig. 1 ] illustrates the main elements of a hydrogen-powered spark-ignition internal combustion engine equipped with a ''blow-by'' circuit comprising an oil settler,

[0035] - Figure [Fig . 2] is a cross-sectional view of a hydrogen-powered internal combustion engine and equipped with a circuit for recycling the gases from a lower housing of the engine comprising an oil settler,

[0036] - Figure [Fig . 3] is a cross-sectional view of a hydrogen-powered internal combustion engine and equipped with a circuit for recycling the lower housing gases comprising an oil settler and a blade device according to the invention,

[0037] - Figure [Fig. 4] illustrates the lower housing gas exhaust chimney and the placement of a blade device according to the invention ,

[0038] - Figure [Fig. 5] illustrates the main elements of a blade device according to a first embodiment, and

[0039] - Figure [Fig. 6] illustrates the main elements of a blade device according to a second embodiment.

[0040] Detailed description

[0041] The internal combustion engine according to the invention comprises a blade device on which the oil-laden combustion gases impact in order to reduce the speed and promote the condensation of the oil, returning to the lower housing 1 b in the form of droplets trickling down the chimneys. A first separation of the oil from the combustion gases is thus carried out.

[0042] The gases then continue their journey to be treated by settling in a conventional manner.

[0043] The internal combustion engine according to the invention comprises a blade device 5e arranged between the lower housing gas exhaust chimney, known as "blow-by" chimney 5d, and the pump 5a. Figure [Fig . 4] illustrates the placement of this blade device 5e.

[0044] The blade device 5e has the effect of condensing the oil contained in the lower housing gases, called "blow-by" gases, charged with hydrogen rising from the lower housing 1 b of the engine before their arrival in the pump 5a and the oil settler 5b. The oil thus condensed flows back into the lower housing 1 b of the engine along the "blow-by" chimney 5d.

[0045] The gases thus pre-decanted have their quantity of oil reduced before they are admitted into the pump 5a and the oil settler 5b. Since the H2molecule is very small, it also inserts into the oil. Thus, separating a certain quantity of oil makes it possible to minimize the quantity of oil to be treated upstream of the pump by the main settling .

[0046] A first embodiment of the blade device 5e is illustrated in Figure [Fig. 5]-

[0047] The blade device 5e comprises a base 10 provided with domed buttons 1 1 so as to be arranged in the ''blow-by'' chimney 5d. At least two louvers 1 2 are attached to the base by a first proximal end. The other distal end of the louvers 1 2 is attached to an upper domed button 1 1 a allowing positioning in the ''blow-by'' chimney.

[0048] A second embodiment of the blade device 5e is illustrated in Figure [Fig 6]. As in the first embodiment, the blade device 5e comprises a base 10 provided with domed buttons 1 1 so as to be arranged in the ''blow-by'' chimney 5d. At least two louvers 12 are attached to the base 10 by a first proximal end.

[0049] However, in this second embodiment, at least one of the louvers 1 2 is extended by a blade 1 2a. The blades 1 2a have the particularity of forming an inclination with respect to the base 10 different from the inclination of the louvers 12 with respect to the base 10. This difference in inclination makes it possible to further slow down the gases and possibly create turbulence, thus promoting the condensation of the oil by increasing the duration of contact of the gases with the louvers and the blades.

[0050] In this embodiment, all the blades 1 2a are connected in pairs by means of a pin 1 2b, the blade 12a furthest from the base then supporting an upper domed button 1 1 a allowing positioning in the "blow-by" chimney.

[0051] The blade device 5e makes it possible to reduce the amount of oil in the gases admitted into the pump 5a so as to reduce the damage thereof as well as the risk of fire. By reducing the quantity of oil to be treated, the H2concentration is minimized, which must be contained below the 4% limit. Indeed, this limit is a flammability limit, beyond this value there is a risk of detonation .

Claims

CLAIMS1. Powertrain comprising an internal combustion engine (1), an air intake circuit (3), a circuit for recycling gases from a lower housing of the engine (5) comprising a pump (5a) directing gases from at least one lower housing (1b) gas exhaust chimney (5d) to an oil separator (5b) connected at the outlet to a clean oil gas line (5c), tapped into the air intake circuit (3), an oil return circuit (7) allowing the oil decanted in the oil separator (5b) to return to the oil layer present in the lower housing (1b) of the internal combustion engine (1) located under the cylinders (1a), and a ventilation line (8) tapped upstream of the clean gas line (5c) and bringing fresh air into the lower housing (1b), sucked in by the pump (5a), the powertrain being characterized in that it comprises a blade device (5e) at the outlet of the lower housing gas exhaust chimney (5d) and upstream of the pump (5a), the blade device (5e) comprising at least two louvers (12) arranged so that the oil comprised in the lower housing gases condenses at least partially on their surface and flows into the lower housing gas exhaust chimney (5d) to the internal combustion engine (1).

2. Powertrain according to claim 1, wherein the blade device (5e) comprises a base (10) to which at least two louvers (12) are attached by a first proximal end.

3. Powertrain according to claim 2, wherein the base is provided with domed buttons (11), an upper domed button (11a) being attached to a second distal end of the louvers (12), the domed buttons (11) and the upper domed button (11a) allowing the blade device (5e) to be positioned in the lower housing gas exhaust chimney (5d).

4. Powertrain according to claim 2, wherein at least a part of the louvers (11) is extended by a blade (12a) forming an inclination with respect to the base (10) different from the inclination of the louvers (12) with respect to the base (10).

5. Powertrain according to claim 4, wherein the base is provided with domed buttons (11), all the blades (12a) being connected in pairs by means of a pin (12b), the blade (12a) furthest from the base then supporting an upper domed button (11a), the domed buttons (11) and the upper domed button (11a) allowing the blade device (5e) to be positioned in the lower housing gas exhaust chimney (5d).

6. Powertrain according to any one of claims 1 to 5, wherein the internal combustion engine operates at least partially on hydrogen.

7. Powertrain according to any one of claims 1 to 6, wherein the exhaust line comprises at least one emission control device.

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