WO2019016220A1

WO2019016220A1 - Cylinder head for a heat engine, equipped with an exhaust pipe

Info

Publication number: WO2019016220A1
Application number: PCT/EP2018/069416
Authority: WO
Inventors: Riowen HEDOUX
Original assignee: Renault S.A.S
Priority date: 2017-07-19
Filing date: 2018-07-17
Publication date: 2019-01-24
Also published as: FR3069285A1; EP3655639B1; EP3655639A1; FR3069285B1

Abstract

The invention relates to a cylinder head (1) of a heat engine, comprising: a cylinder head body (2) to be mounted on a cylinder block of the engine, said cylinder head body (2) having an exhaust side (11); and a cylinder head cover covering the cylinder head body (2). According to the invention, the cylinder head body (2) comprises an exhaust pipe (24) connected to an outlet (22) and located on the exhaust side (11), said exhaust pipe (24) being open opposite the cylinder head cover.

Description

Cylinder head for combustion engine equipped with a conduit

evacuation

The invention relates to a cylinder head for a heat engine. More particularly, the invention relates to a cylinder head having a risk of ignition.

In known manner, a cylinder head for a combustion engine comprises a cylinder head body in which intake ducts, exhaust ducts and injection and / or ignition systems, valve systems and at least one camshaft. The cylinder head has an exhaust side and an intake side. In addition, the cylinder head includes a cylinder head cover which is mounted on the cylinder head body.

However, according to a thermal engine safety study, there is a risk of oil leaking from the interface between the cylinder head cover and the cylinder head. This oil may originate from a condensation of the oil vapor in contact with the cylinder head cover. The oil vapor can come from the oil contained in different parts of the engine where the temperature is high.

The oil flow can reach a mounting flange on the exhaust side of the cylinder head. This fastening flange is part of an exhaust line for bringing the gas produced after combustion to a catalytic converter, or catalyst, to transform it into a gas with fewer toxic constituents. The catalytic converter, in its operating state, can reach a very high temperature, in particular of the order of 800 ° C. to 1000 ° C.

Thus, if the oil reaches the clamp, it can flow to the catalytic converter. The contact between the oil and said catalytic converter, especially when it is in operation at high temperature, may cause ignition, which could cause serious damage to the vehicle. The safety of a driver in this case is threatened.

Thus, an object of the invention is to provide a cylinder head which does not present a risk of ignition and ensures the safety of the driver in the vehicle.

For this purpose, the invention relates to a combustion engine cylinder head comprising

a cylinder head intended to be mounted on a crankcase of the engine; said cylinder body having an exhaust side; and

- a cylinder head cover over the breech body.

According to the invention, the bolt body comprises an exhaust duct located on the exhaust side and connected to an outlet; and said exhaust duct being open opposite the cylinder head cover.

In this document, the term "exhaust side" of the cylinder head body the side where are arranged exhaust ducts. It can also be the side where is disposed an exhaust manifold in the case where it is integrated in the cylinder head.

Thanks to the invention, when there is a seepage of the oil at the interface between the cylinder head body and the cylinder head cover on the exhaust side, the oil is immediately collected by the exhaust pipe and brought to the exit. The exhaust vent is a barrier to prevent oil from falling onto a mounting flange. In this way, the oil can not reach either the fixing flange or the catalytic converter connected to said flange. There is therefore no risk of contact between the oil and the catalytic converter operating at high temperature.

Note that the oozing of oil between the cylinder head and the cylinder head cover is only possible if there is a failure of a seal interposed between these two parts.

According to another characteristic of the invention, the exhaust duct comprises a slope directed towards the outlet. In this way, the oil flows more quickly to the outlet and does not stagnate in the exhaust duct. This structure is particularly effective in case of heavy oil flow.

According to a characteristic of the invention, the output is an orifice. For example, the exhaust duct is an open groove at its upper face. The orifice is made at the bottom of the groove.

In the present description, the yoke body has a width extending in a first direction and a height extending in a second direction. The bolt body comprises at least one connecting zone intended to receive an attachment flange of an exhaust line and which has a first dimension defined in the first direction. According to one characteristic of the invention, the evacuation duct has a first dimension, defined in the first direction, greater than the first dimension of the connecting zone.

In other words, the exhaust duct has a length, defined in the first direction, greater than the width of the connecting zone, measured in the same direction. Now, it is known that the connection zone has dimensions approximately identical to those of the fastening flange. Therefore, the exhaust duct has a length exceeding the width of the fastening flange once it is mounted on the bolt body.

According to the preceding paragraph, the outlet is disposed at one end of the exhaust duct which is furthest from the connection zone. In this way, the oil is evacuated far from the area where the fastening flange is located. he there is therefore no risk of contact between the oil and this flange.

According to one characteristic of the invention, an area in relief relative to the upper face of the exhaust duct is disposed between said exhaust duct and an outer edge of the bolt body. By "outer edge" is meant here the edge that faces outwardly from the cylinder head body on the exhaust side. The raised area prevents oil from spilling out of the exhaust duct in the event of engine vibration or other events that may cause the oil to pass out of the exhaust duct laterally.

In addition, the engine can be inclined relative to the horizontal when the car is on a slope or straddling a sidewalk. In another example, the motor can be installed inclined in the engine compartment, in particular between 8 ° and 35 ° relative to the horizontal. In both cases, the oil collected by the evacuation side exhaust pipe tends to flow laterally out of said duct. Thanks to the relief zone, the oil is kept in the exhaust duct. The raised area may be a rib that extends along the exhaust duct.

According to one embodiment of the invention, the exhaust duct and the outlet are integral with the bolt body. The exhaust duct and the outlet integrated into the cylinder head can be obtained by different methods, for example by a sand molding process.

Alternatively, the exhaust duct and the outlet are made by machining. For example, the exhaust duct is obtained by removing the material of the bolt body while the outlet is made by drilling. We therefore does not need to redo a new cylinder head to integrate the exhaust duct and outlet.

The invention also relates to a heat engine comprising a cylinder head made according to one of the preceding characteristics.

The invention also relates to a vehicle comprising such a heat engine.

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

- Figure 1 shows, schematically, a front view of the exhaust side of a cylinder head according to the invention; a catalytic converter covered by a heat shield being connected to said cylinder head;

FIG. 2 represents the same view as FIG. 1 and without heat shield;

FIG. 3 represents a sectional view of the cylinder head along the plane III-III illustrated in FIG. 2;

- Figure 4 shows a perspective view and a top view of the cylinder head of Figure 1 in the absence of a cylinder head cover;

FIG. 5 represents a plan view from above of the breech of FIG. 1 without the breech cover;

FIG. 6 represents a perspective view according to section VI-VI illustrated in FIG. 5.

Referring to Figures 1 and 2, there is an exhaust side 11 of a cylinder head 1 comprising a cylinder head body 2 and a cover 3 attached to one another, for example by screwing. The cylinder body 2 incorporates intake ducts and exhaust ducts (not visible in the figures).

In this description, unless otherwise indicated, the terms "high", "low", "superior", "Lower" respectively correspond to the top and bottom of Figures 1 and 2 as shown. A first direction X extends from left to right of Figures 1 and 2. Furthermore, a second direction Z, perpendicular to the first direction X, extends from top to bottom of Figures 1 and 2. The exhaust side 11 of the bolt body 2 has a width extending in the first direction X and a height extending in the second direction Z.

According to the invention and in this example, an exhaust manifold (not visible in the figures) is integrated in the cylinder head body 2. By exhaust manifold is meant the element which groups together all the gases coming out of the different ducts. exhaust to a single outlet. Thus, on the exhaust side 11, there is a single exhaust outlet which is the outlet of the exhaust manifold. It communicates with a catalytic converter 4 connected to the cylinder head body 2.

The catalytic converter 4 is connected to the bolt body 2 via a fastening flange 5. This catalytic converter 4 is part of an exhaust line whose function is to recover post-combustion gas, otherwise called exhaust, make it less toxic and then toss it out. A heat shield 41 wraps around the catalytic converter 4 to protect it against heat and also limit its thermal radiation to other components less resistant to heat.

The fastening flange 5 is fixed on the bolt body 2 to an area called the connecting zone 23. The connecting zone 23 has dimensions approximately identical to those of the fastening flange 5. Of course, in the case where the exhaust manifold is not integrated in the bolt body, it may have several connecting zones, each being intended to receive a fastening flange. Alternatively, there may be a single bonding area for a single fastening flange that covers all the exhaust outlets.

In Figure 3, there is clearly an interface 6, or contact surface, between the cylinder head cover and the cylinder head. In this example, the outer edge 21 of the bolt body protrudes from the outer edge 31 of the cylinder head cover in a third direction Y. This third direction Y is perpendicular to the first and second directions X and Z.

In FIG. 4, the cylinder head cover 3 is masked to show an exhaust duct 24 made in the cylinder head body 2. According to the invention and in this example, the exhaust duct 24 is a groove 240 made at a upper face 25 of the cylinder head body 2. This upper face 25 is opposite the valve cover 3. Thus, it can be said that the upper opening 245 of the exhaust pipe 24 is flush with the upper face 25 of the cylinder head body 2.

Specifically, the evacuation duct 24 is made in a sidewalk zone 27 of the bolt body 2. The sidewalk zone 27, of width d3, is opposite the bolt cover 3.

The exhaust duct 24 has a length Li in the first direction X and extending parallel to the outer edge 21 of the bolt body 2. The exhaust duct 24 is located above the connection zone 23 of the barrel body. The connecting zone 23 has a width Pi measured in the first direction X. The length Li of the exhaust pipe 24 is greater than the width Pi of the connecting zone 23.

Since the connecting zone 23 has dimensions approximately identical to those of the fastening flange 5, it can be considered that the width of the connecting zone 23 is equivalent to that of the fastening flange 5 measured in the first direction X Thus, the exhaust duct 24 exceeds the mounting flange 5 in the first direction. By way of example, the length L1 of the exhaust duct is 135.5 mm and the width of the fastening flange 5 is 83.5 mm. The difference between the length Li of the exhaust duct 24 and the width of the fixing flange 5 is about 52 mm.

As previously described, the outer edge 21 of the bolt body 2 is shifted outwardly relative to the outer edge 31 of the valve cover 3 so that the exhaust duct 24 is half covered by the valve cover 3 and half clear, as shown in Figure 3. With such a configuration, one can imagine that the liquid flowing along the walls of the valve cover 3 falls into the exhaust pipe 24 and that it is thus evacuated the area at risk.

In FIGS. 5 and 6, an outlet 22 is connected to the discharge duct 24. According to the invention and in this example, the outlet 22 is an orifice 220 pierced in a bottom 244 of the evacuation duct 24. Here, "Bottom" means the face opposite to the upper opening 245 of the exhaust duct 24.

The outlet 22 remains remote from the connection zone 23 and the fixing flange 5 by a distance d 1 measured in the first direction X. This distance di is, for example, 42.4 mm. In this example, the outlet 22 is located near a first end 241 of the exhaust duct 24 because this end is further from the connecting zone 23 than a second end 242.

According to the invention and in this example, the bottom 244 of the exhaust duct is inclined with respect to the first direction X with a slope directed towards the outlet 22, for example 1.5 °. In this way, when the oil is recovered in the exhaust pipe 24, it is quickly brought to the orifice 220 and discharged to the outside of the connection zone 23 and therefore far from the fixing flange 5. The direction of flow of the oil is illustrated by arrows F i in FIG.

In another embodiment, depending on the width d3 of the curb zone 27, the slope may be inclined more than 1.5 °.

The exhaust duct 24 is disposed very close to the interface 6 between the cylinder head cover and the cylinder head body in order to immediately collect oil coming from this interface. In this way, the oil can not reach the fixing flange 5. Indeed, despite the fact that the fixing flange 5 and the catalytic converter 4 are covered by the heat shield 41, there is a space between the heat shield 64 and the cylinder head 2 due to the manufacturing tolerance of these two parts. Therefore, in the absence of the exhaust pipe 24, the oil can reach the fastening flange 5 passing through this gap.

Optionally, as illustrated in FIG. 6, a raised area 26 with respect to the upper opening 245 of the evacuation duct 24 is disposed between the discharge duct 24 and the outer edge 21 of the bolt body. In this example, the relief zone 26 is a protruding band 260 which extends parallel to the evacuation conduit 24. This relief zone 26 prevents the lateral overflow of the oil from the evacuation duct 24, which can happen when the cylinder head 1 is in an inclined position. In other words, the relief zone 26 with the exhaust duct 24 make it possible to avoid any contact between the discharged liquid and the exhaust flange.

The distance d2 measured in the third direction

Y, between the exhaust duct 24 of the outer edge 21 of the cylinder head body may be about 4.7 mm. Of course, it is possible to make modifications to the invention without departing from the scope thereof.

For example, the exhaust duct may extend all along the exhaust side of the cylinder head. In this case, the exhaust duct may have one of the open ends through which the oil is discharged to the outside.

In another example, the exhaust duct is connected to two evacuations. In this case, it comprises a first slope directed towards the first evacuation and a second slope towards the second evacuation.

The cylinder head according to the invention comprises an exhaust duct and an outlet for draining any oil seeps along the exhaust side out of the risk zone, namely the connection zone with the fastening flange. In this way, it avoids any contact between the oil and the catalytic converter, so any risk of ignition resulting from this contact.

Claims

1. Cylinder head (1) comprising

- a cylinder head body (2) intended to be mounted on a crankcase of the engine; said yoke body (2) having an exhaust side (11); and

- a cylinder head cover (3) covering the cylinder head body (2);

said yoke (1) being characterized in that the yoke body (2) comprises an exhaust duct (24) located on the exhaust side (11) and connected to an outlet (22), said exhaust duct ( 24) being open next to the cylinder head cover (3).

2. Cylinder head (1) according to claim 1, characterized in that the discharge duct (24) comprises a slope directed towards the outlet (22).

3. Cylinder head (1) according to claim 2 or according to claim 1, characterized in that the outlet (22) is an orifice (220).

4. Cylinder head (1) according to one of claims 1 to 3, the yoke body (2) having a width extending in a first direction (X) and a height extending in a second direction (Z), the yoke body (11) comprising at least one connecting zone (23) for receiving an attachment flange (5) of an exhaust line and having a first dimension (Pi) defined in the first direction (X) , said yoke (1) being characterized in that the discharge duct (24) has a first dimension (Li), defined in the first direction (X), greater than the first dimension (Pi) of the connecting zone ( 23).

Cylinder head (1) according to claim 4, characterized in that the outlet (22) is arranged at a end (241) of the exhaust duct (21) which is furthest from the connection zone (23).

6. Cylinder head (1) according to one of claims 1 to 5, characterized in that a raised area (26) relative to the upper face (245) of the discharge duct (24) is disposed between said duct discharge (24) and an outer edge (21) of the bolt body (2).

7. Cylinder head (1) according to one of claims 1 to 6, characterized in that the exhaust duct (24) and the outlet (22) are integral with the cylinder head body (2).

8. Cylinder head (1) according to one of claims 1 to 6, characterized in that the discharge duct (24) and the outlet (22) are made by machining.

9. A combustion engine characterized in that it comprises a yoke (1) according to one of the preceding claims.

10. Motor vehicle characterized in that it comprises a combustion engine according to claim 9.