External air ventilation system for an upper engine and a lower engine

Abstract

Ventilation device (1) of an internal combustion engine of a motor vehicle, comprising at least one external air inlet (3), external air filtering means (4), and at least one common duct (5) which communicates with the filtering means (4) and which is able to distribute the filtered external air into distribution members (6a, 6b, 6c) of the external air to the engine. The ventilation device (1) comprises at least two distribution members (6a, 6b) which distribute external air into a crankcase of the engine, preferably at two opposite points, and at least one distribution member (6c) which distributes external air into a cylinder head cover of the engine.

Description

[0001] DESCRIPTION

[0002] TITLE: EXTERNAL AIR VENTILATION SYSTEM FOR AN UPPER ENGINE AND A LOWER ENGINE

[0003] Technical area

[0004] The present invention relates to internal combustion engines for motor vehicles, and in particular to spark-ignition internal combustion engines running on hydrogen .

[0005] Each fuel has a lower explosive limit and an upper explosive limit. Explosive limits define the range of fuel concentration in air within which the fuel will ignite. Below the lower explosive lim it, there is not enough fuel for the mixture to ignite, and above the upper explosive limit, there is not enough air for the mixture to ignite.

[0006] The lower explosive limit of hydrogen is 4%, which means that when there is a concentration of 4% or more of hydrogen in the air, the hydrogen ignites and can cause an explosion . Its upper explosive limit is 75%, which means that when there is a concentration of at least 75% hydrogen in the air, the mixture will not ignite.

[0007] LPG fuel, essentially comprising methane, has an explosive range of between 5% and 1 5%, and diesel fuel, essentially comprising diesel fuel, has an explosive range of between 0.6% and 6.5%.

[0008] Hydrogen is an extremely flammable and reactive fluid, which is more flammable than petrol, diesel, LPG or CNG fuel, for example, because it has a large explosive range. Hydrogen is therefore a particularly dangerous fluid, especially when used in closed volumes. During engine operation, leaks occur and fuel is released into the lower part of the engine (also known as the "lower engine"), delimited by a crankcase and a lower engine casing which closes off the crankcase at the bottom .

[0009] In order to avoid combustion in closed engine spaces, an effective ventilation system is needed to dilute the gases in the crankcase and reduce fuel concentration. A system for diluting crankcase gases with fresh air by means of a pump located in an engine oil decantation circuit is currently known from the unexamined patent application FR 23 00437. Downstream of the air filter, this pump takes clean air from the engine's air intake circuit and sends it into the engine's lower crankcase to dilute the gases.

[0010] However, such a system is technically and financially difficult to implement. What's more, this system is primarily designed to regulate the air flow but not to distribute it as evenly as possible throughout the engine crankcase, and the upper part of the engine (also known as the "upper engine") , delimited by a cylinder head and an engine head cover that covers the cylinder head at the top, is not affected by the ventilation.

[0011] Explanation of the invention

[0012] The aim of the present invention is to overcome the aforementioned problems and, in particular, to effectively dilute the gases in the engine crankcase, taking into account the distribution of air throughout the engine. The object of the invention is therefore a ventilation device of an internal combustion engine of a motor vehicle comprising at least one external air inlet, external air filtering means, at least one common duct which communicates with the filtering means and which is able to distribute the filtered external air into external air distribution members towards the engine.

[0013] This device comprises at least two distribution devices that distribute external air to an engine crankcase, and at least one distribution device that distributes external air to an engine cylinder head cover.

[0014] Advantageously, the said distribution device comprises at least one external air pipe fitted with at least one non-return valve.

[0015] Said distributor includes at least one connection point for connection to a motor connector.

[0016] According to an embodiment, the two connection points of two distribution members distributing external air in an engine crankcase are connected to two connectors of the engine crankcase, these connectors being located at two opposite points of the engine. Advantageously, a crankcase connector is located on , or close to, a distribution face of the engine, and a crankcase connector is located on, or close to, a coupling face of the engine.

[0017] In one embodiment, the connection point of the distribution member distributing external air in an engine cylinder head cover is connected to a connector on the engine cylinder head cover.

[0018] Advantageously, the external air inlet allows fresh air to be injected inside the engine and particularly into its insulated spaces, such as the crankcase and the cylinder head cover.

[0019] The external air inlet and the external air filtering means are separate from those of an engine air intake circuit which fills the engine combustion chambers with air.

[0020] In one embodiment, said engine is a hydrogen-powered motor vehicle internal combustion engine.

[0021] The invention also relates to an engine comprising a ventilation device as defined above.

[0022] The invention also relates to a motor vehicle comprising an engine as defined above, which includes a ventilation device as also defined above.

[0023] Brief description of the figures

[0024] Other purposes, features and advantages of the invention will become apparent from the following description , which is g iven solely by way of non-limiting example and is made with reference to the appended drawings in which :

[0025] - [Fig . 1 ] is a schematic view of an engine ventilation system comprising three external air distribution components ;

[0026] - Figure [Fig. 2A] is a schematic view of the connectors on the engine crankcase;

[0027] - Figure [Fig. 2B] is a schematic view of the connector on the engine cylinder head cover;

[0028] - Figure [Fig. 3A] is a schematic view of the ventilation device integrated on the motor, its connection points being linked to the motor connectors; - Figure [Fig. 3B] is a schematic view of the ventilation device integrated on the motor, its connection points being linked to the motor connectors; and

[0029] - Fig . 4] is a simplified schematic view of an engine ventilation system comprising five external air distribution components.

[0030] Detailed description

[0031] Figure 1 shows a ventilation device for a motor vehicle internal combustion engine, designated by the numerical reference 1 . This device 1 is designed to ventilate a spark-ignition internal combustion engine 2, and in particular a hydrogen-powered spark-ignition internal combustion engine 2.

[0032] Hydrogen is a particularly flammable and reactive fuel with a high explosive range. During engine 2 operation , fuel leaks into the engine 2 crankcase. To prevent abnormal combustion in an engine 2 running on hydrogen, an effective ventilation device 1 is required to dilute the gases in the engine 2 crankcase and reduce the concentration of fuel in the closed volumes of the lower part of the engine 2 and the upper part of the engine 2.

[0033] The ventilation device 1 comprises at least one air inlet 3, external air filtering means 4, at least one common duct 5 which communicates with the filtering means 4, and at least three distribution members 6a, 6b, 6c which distribute external air in the engine 2.

[0034] The air inlet 3 allows external air to be collected and injected inside the engine 2, more specifically into a crankcase 7 at the bottom of the engine, and into a cylinder head cover 8 at the top of the engine. The engine crankcase and cylinder head cover are illustrated in Figures 2A and 2B. Filtering means 4 recover the external air captured by air inlet 3 and the filter. In particular, they prevent particles of dirt and dust harmful to engine operation from infiltrating the engine 2.

[0035] The common duct 5 communicates with the filtration means 4 and enables the filtered external air to be distributed to the distribution members 6a, 6b and 6c via a distribution means 9.

[0036] Advantageously, the air inlet 3 and the filtration means 4 of the ventilation device 1 are independent, i.e. distinct, from the air inlet and the filtration means of the air intake circuit which enables the combustion chambers of the engine 2 to be filled with air. In fact, when the ventilation device 1 shares the same air inlet 3 and the same filtration means 4 as the air intake circuit, the common duct 5, which is mounted downstream of the common filtration means 4, is subjected to a greater negative pressure due to the pressure drop in the filtration means and the suction of air by the engine 2. As a result, the circulation of ventilation air towards the lower engine and towards the upper engine is more difficult.

[0037] The ventilation device 1 illustrated in Figure 1 comprises two distribution members 6a, 6b which distribute external air in the crankcase 7 of the engine 2, and a distribution device 6c which distributes external air in the cylinder head cover 8 of the engine 2. The said distribution members 6a, 6b, 6c enable filtered external air to be distributed in the engine 2, on the one hand in the lower engine, and on the other hand in the upper engine. It is possible that the ventilation device 1 comprises more than three distribution members 6a, 6b, 6c.

[0038] Each distribution member 6a, 6b, 6c comprises at least one external air pipe 1 0 fitted with at least one non-return valve 1 1 , enabling the direction of the external air to be controlled. Advantageously, the pipes 1 0 are flexible pipes.

[0039] Each distribution member 6a, 6b, 6c also comprises at least one connection point 1 2a, 12b, 1 2c intended to be connected to a connector of the engine 2. A connection point 12a, 1 2b, 1 2c is a fitting wh ich may comprise beaded ends, fir-tree type ends or corrugated ends.

[0040] The motor comprises a number of connectors 13a, 13b, 13c for connection to the connection points 1 2a, 1 2b, 12c of the external air distribution members 6a, 6b, 6c. These connectors 13a, 13b, 13c are shown in Figures 2A and 2B, in one embodiment.

[0041] In Figure 2A, two engine connectors 13a, 13b are illustrated in relation to the ventilation of the lower engine. These connectors 13a, 13b are located in the crankcase 7 of the engine 2, at two opposite points. Their distance enables the ventilation device 1 to ventilate the engine 2 more efficiently. In fact, by injecting external air into the engine 2 at two distant locations, the fuel is diluted more quickly, throughout the crankcase 7 of the engine 2.

[0042] Preferably, a first connector 13a is located on a distribution face of the crankcase (as illustrated in Figure 2A) or alternatively on a point on a side face of the crankcase which is located close to the distribution face, and a second connector 13b is located on a mating face of the engine or alternatively on a point on a side face of the crankcase which is located close to the mating face (as illustrated in Figure 2A). Such an arrangement of connectors 13a, 13b enables the central cylinders of the engine to be ventilated more efficiently.

[0043] With reference to Figure 2B, the motor connector 13c is located in the cylinder head cover 8 of the engine 2, allowing the upper volumes of the engine 2 to be ventilated.

[0044] Figures 3A and 3B show the integration of the ventilation device 1 on the engine 2. When the connection points 1 2a, 12b, 1 2c of the ventilation device 1 are connected to the connectors 13a, 13b, 13c of the engine 2, the lower part of the engine 2 is ventilated by means of the connection points 1 2a, 1 2b connected to the cylinder crankcase 7, and the upper part of the engine 2 is ventilated by means of the connection point 1 2c connected to the cylinder head cover 8.

[0045] Figure 3A illustrates the ventilation device 1 integrated on the engine 2 by means of a connection point 1 2b connected to a connector 13b on the crankcase 7 of the engine 2.

[0046] Figure 3B illustrates the ventilation device 1 integrated on the engine 2 by means of a connection point 1 2a connected to a connector 13a on the cylinder crankcase 7 of the engine 2, and by means of a connection point 12c connected to a connector 13c on the cylinder head cover 8 of the engine 2.

[0047] Figure 4 illustrates another embodiment, in which the ventilation device 1 comprises five distribution members 6a, 6b, 6c, 6d, 6e, enabling the engine 2 to be ventilated more quickly in particular. The connection points 1 2 of the distribution members 6a, 6b, 6c, 6d, 6e are, for example, connected to connectors 13 located in high-risk areas of the engine 2.

[0048] The ventilation device 1 shown in Figure 4 also includes a duct 14 located between the external air inlet 3 and the external air filtering means 4. This configuration enables the ventilation device 1 , for example, to be adapted to the layout of the engine 2 in the vehicle.

[0049] It is not impossible for the ventilation device 1 to comprise several pipes and / or ducts and / or non-return valves, positioned in different configurations to facilitate integration of the ventilation device 1 on the engine 2.

[0050] It should be noted that the ventilation device 1 just described can advantageously be used to ventilate all types of internal combustion engine 2 in a motor vehicle.

Claims

CLAIMS1 . Ventilation device (1 ) of an internal combustion engine (2) of a motor vehicle comprising at least one external air inlet (3), external air filtering means (4) , at least one common duct (5) which communicates with the filtering means (4) and which is able to distribute the filtered external air into distribution members (6a, 6b, 6c) of the external air to the engine, characterised in that it comprises at least two distribution members (6a, 6b) which distribute external air in a crankcase (7) of the engine (2), and at least one distribution member (6c) which distributes external air in a cylinder head cover (8) of the engine (2).

2. Ventilation device (1 ) of an engine (2) according to claim 1 , in which said distribution member (6a, 6b, 6c) comprises at least one external air pipe ( 10) equipped with at least one non-return valve (1 1 ) .

3. Ventilation device (1 ) of a engine (2) according to one of claims 1 and 2, in which said distribution member (6a, 6b, 6c) comprises at least one connection point ( 12) intended to be connected to a connector ( 13) of the engine (2) .

4. Ventilation device (1 ) of an engine (2) according to claim 3, in which the two connection points ( 12a, 1 2b) of two distribution members (6a, 6b) are connected to two connectors ( 13a, 13b) of the cylinder crankcase (7) of the engine (2), these connectors ( 13a, 13b) being located at two opposite points of the engine (2).

5. Ventilation device (1 ) of an engine (2) according to claim 4, in which a connector (13a) of the crankcase (7) is located on , or close to, a distribution face of the engine, and a connector (13b) of the crankcase (7) is located on, or close to, a coupling face of the engine.

6. Ventilation device ( 1 ) of an engine (2) according to any one of claims 1 to 3, in which the connection point ( 12c) of the distribution member (6c) is connected to a connector (13c) of the cylinder head cover (8) of the engine (2) .

7. Ventilation device ( 1 ) of an engine (2) according to any one of claims 1 to 6, in which the external air inlet (3) makes it possible to inject freshair into the interior of the engine (2) , and particularly into its insulated volumes, such as the crankcase (7) and the cylinder head cover (8) .

8. Ventilation device (1 ) according to claim 7, in which the external air inlet (3) and the external air filtering means (4) are separate from those of an engine (2) air intake circuit which enables the combustion chambers of the engine (2) to be filled with air.

9. Ventilation device ( 1 ) of an engine (2) according to any one of claims 1 to 8, said engine (2) being a hydrogen-powered motor vehicle internal combustion engine (2).

10. Engine (2) comprising a ventilation device ( 1 ) according to any one of claims 1 to 9.1 1 . Motor vehicle comprising an engine (2) according to claim 1 0 which includes a ventilation device ( 1 ) according to any one of claims 1 to 7.

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