Device for attaching a heat exchanger to a cylinder head of an internal combustion engine

Abstract

The present invention relates to a device (1) for attaching a heat exchanger (3) to a cylinder head of an internal combustion engine, the attachment device (1) comprising an opening (12) through which air can pass from the heat exchanger (3) in the direction of an air intake disposed in the cylinder head, the attachment device (1) being characterised in that it comprises at least one retention zone (14), and means for maintaining a liquid present in the retention zone (14).

Description

[0001] DESCRIPTION

[0002] Title of the invention: Device for fixing a heat exchanger to a cylinder head of an internal combustion engine

[0003] The present invention relates to the field of the automotive industry and more specifically concerns a device for fixing a heat exchanger to the cylinder head of an internal combustion engine.

[0004] In a vehicle with a thermal or internal combustion engine, the engine has an air intake inlet to inject air into the engine's combustion chambers. This inlet is located on an intake face of the thermal engine, to which fresh air supply devices are attached. On the opposite side of the engine to this intake face, there is an exhaust face, to which exhaust line devices are attached to convey burnt gases to the outside of the engine and to pollution control systems. Both faces extend longitudinally to the engine, i.e. in the direction of its length.

[0005] To reduce pollutant emissions, such a heat engine is generally equipped with a recirculation line for burnt gases and gases from oil vapors, emanating from the engine. The burnt gases are returned, often after compression upstream of an intake manifold, to the engine's intake inlet, to be mixed with fresh air coming from outside the vehicle, before being re-injected into the engine's air intake circuit.

[0006] The recirculated gases comprise high-pressure gases taken directly from the engine exhaust face or from an exhaust manifold attached to the engine, and low-pressure gases taken further downstream, particularly at the level of a pollution control device such as a catalyst or a nitrogen oxide trap.

[0007] To ensure that the recirculated air and gases injected into the engine's air intake system are as cool as possible, a water-to-air heat exchanger is often used upstream of the air intake system. This improves engine efficiency. This heat exchanger is often placed between a throttle body and an engine cylinder head, and as close to it as possible so that the air does not have time to heat up. The heat exchanger, which is made of metal, is often equipped with one or more plastic devices for attaching the heat exchanger to the parts upstream and downstream of the heat exchanger. In particular, a first device is commonly called the heat exchanger inlet box and is connected to the throttle body, while a second device is commonly called the cylinder head mounting box and allows the heat exchanger to communicate with the engine's cylinder head through a cylinder head plenum.

[0008] Depending on the architecture of the powertrain in which the thermal engine is included, and its layout in the vehicle, when the vehicle is parked, particularly on a slope, liquid retention areas may form between the heat exchanger and the plenum of the engine cylinder head. In these retention areas, condensate may accumulate, this condensate being oil, coolant, or water. These last two condensates are problematic because if they go towards the engine pistons, when the cylinder block is located under the cylinder head, a high concentration of water can end up in the combustion chambers and damage the engine.

[0009] To prevent this engine damage, a powertrain architecture must be found that does not allow the formation of such liquid retention zones. However, such an architecture is difficult to find when the cylinder block is located under the cylinder head, since a minimum parking slope for the vehicle cannot be guaranteed.

[0010] The present invention aims to at least partially overcome the drawbacks of the technique by providing a device for fixing a heat exchanger to a cylinder head of an internal combustion engine, an arrangement comprising an internal combustion engine, a heat exchanger and such a fixing device, and an assembly comprising a heat exchanger, an air inlet box and such a fixing device, which retain the condensates and send them to a less problematic area than the combustion chambers of the engine.To this end, the invention proposes a device for fixing a heat exchanger to a cylinder head of an internal combustion engine, the fixing device comprising an opening capable of being passed through by air coming from the heat exchanger and heading towards an air intake inlet arranged in the cylinder head, the fixing device being characterized in that it comprises at least one retention zone, and means for maintaining a liquid present in the retention zone.

[0011] This fixing device according to the invention, also called a fixing box, thus retains the liquids formed by condensation. The holding means allow in particular the condensates to freeze in very cold weather, because the liquids which have condensed in the retention zone are retained there, at least until the liquids retained in this zone reach a certain quantity. In addition, when the vehicle restarts and takes a position in which the retention zone would empty without the holding means of the fixing device, the liquids are retained at least in part in the retention zone, thus preventing damage to an engine of the vehicle, connected to the fixing device.

[0012] The holding means comprise, for example, a rib projecting from a lower wall of the opening. The fixing device is preferably made of molded plastic, the rib is, for example, molded at the same time as the fixing device according to the invention.

[0013] The fixing device according to the invention has the overall shape of a frame comprising four walls delimiting the opening of the fixing device, the air arriving in the opening via a first face of the fixing device, and leaving the opening via a second face of the fixing device, opposite the first face, the first and second faces being substantially orthogonal to the four walls. By "substantially orthogonal" is meant orthogonal to within 30 degrees.

[0014] These first and second faces are for example intended to be arranged parallel to the main extension direction of a camshaft of the internal combustion engine. The first face comprises means for fixing to the heat exchanger, for example a rim allowing tabs of the heat exchanger to close on this rim, and the second face comprises means for fixing to the cylinder head, for example screw holes.

[0015] The bottom wall of the opening is the one of the four walls of the opening which is intended to be substantially parallel to the road when the vehicle is parked or driving on that road. By "substantially parallel" is meant that the bottom wall has an angle of zero or non-zero but less than 30 degrees with the road.

[0016] In a preferred embodiment, the fixing device according to the invention comprises a passage for gas from oil vapors coming from an oil vapor gas distribution channel arranged in the cylinder head, the passage comprising at least one gas outlet orifice provided in the lower wall and a connection with the distribution channel, the outlet orifice being arranged outside the retention zone.

[0017] This distribution channel for gas from oil vapors arranged in the cylinder head is also called a "blowby" passage. The passage arranged in the fixing device according to the invention therefore allows the gas from oil vapors arranged in the cylinder head to exit through the outlet orifice to arrive in the opening of the fixing device, and to be reinjected into the intake inlet of the engine. By being arranged outside the retention zone, the liquids contained in the retention zone cannot empty directly into the passage for the gas from oil vapors and therefore into the distribution channel arranged in the cylinder head. Otherwise, the engine oil would risk becoming loaded with water or pollutants, which would be harmful to the engine.

[0018] The rib extends for example from the first face of the fixing device to the second face of the fixing device, and the outlet orifice is arranged between the rib and the cylinder head. The passage is for example formed on the second face under the lower wall, the cylinder head closing the passage without closing the outlet orifice and the distribution channel opening into the passage, when the cylinder head is secured to the fixing device according to the invention.

[0019] According to a preferred feature of the fixing device according to the invention, the rib comprises at least one evacuation zone for liquid overflowing from the retention zone. This makes it possible to control the evacuation of the excess liquid present in the retention zone, in particular by promoting its gradual evaporation. This evacuation zone also makes it possible to guide this excess liquid towards areas of the fixing device or the cylinder head which are less problematic than the engine air intake inlet.

[0020] In particular, the fixing device according to the invention preferably comprises guide means capable of directing liquid leaving the discharge zone towards the outlet orifice. Thus the excess liquid is directed towards the passage for the gas from oil vapors, and therefore towards the distribution channel which leads to a decanter. This makes it possible not to bring the condensates into the combustion chambers of the engine.

[0021] In one embodiment of the invention, the outlet orifice adjoins the rib at the discharge area, and the guide means form edges of the outlet orifice.

[0022] According to an alternative embodiment, the guide means form a channel extending from the discharge zone to the outlet orifice.

[0023] The evacuation zone is formed, for example, by a lower zone in the rib. For example, the rib has a first height at the evacuation zone, and a second height on the rest of its periphery, higher than the first height. These heights are of course not infinite. The first height and the second height are, for example, optimized to allow maximum retention of the liquid when parked and evaporation of the latter when rolling. Alternatively, the evacuation zone is formed by an orifice in the rib.

[0024] Preferably, the fixing device comprises several outlet orifices, distributed along the rib, the rib comprising as many evacuation zones as outlet orifices, each outlet orifice adjoining one of the evacuation zones and being bordered by guide means capable of channeling the liquid leaving the evacuation zone to the outlet orifice. This distribution is regular in order to create a uniform distribution of the oil coming from the “blow-by” cavity at the level of the air intake plenum of the engine.

[0025] For example, the rib forming a generally rectangular shape, the fixing device according to the invention comprises two outlet orifices symmetrical with respect to a plane of symmetry of the generally rectangular shape, orthogonal to the lower wall, and are distant from each other by at least half of the largest dimension of this generally rectangular shape.

[0026] The invention also relates to an arrangement comprising an internal combustion engine, a heat exchanger and a fixing device according to the invention, connected in a sealed manner on the one hand to a cylinder head of the internal combustion engine and on the other hand to the heat exchanger.

[0027] The invention finally relates to an assembly comprising a heat exchanger, an air inlet box capable of being connected to an air inlet of the heat exchanger, and a fixing device according to the invention capable of being connected to an air outlet of the heat exchanger.

[0028] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0029] [fig 1] represents in perspective an arrangement according to the invention comprising an internal combustion engine, a heat exchanger and a fixing device according to the invention, in one embodiment of the invention,

[0030] [fig 2] is a perspective side view of an assembly according to the invention comprising a heat exchanger, an air inlet box connected to one face of the heat exchanger, and a fixing device according to the invention connected to another face of the heat exchanger, in this embodiment of the invention,

[0031] [fig 3] is a perspective top view of the assembly of figure 2, [fig 4] is a sectional view of the fixing device of figure 2, the sectional plane being parallel to one of the side walls of the fixing device,

[0032] [fig 5] is a view of one side of the fixing device of figure 2, adapted to be connected to a cylinder head of the internal combustion engine of the arrangement shown in figure 1,

[0033] [fig 6] is a perspective view of one face of the fixing device of figure 2, opposite the face shown in figure 5, and

[0034] [fig 7] is an enlargement of an area of ​​the face of the fixing device shown in figure 5.

[0035] According to an embodiment of the invention shown in Figure 1, an arrangement according to the invention comprises an internal combustion engine of which only the cylinder head 2 is shown in Figure 1, a heat exchanger 3 and a fixing device 1 according to the invention, connected in a sealed manner on the one hand to an air outlet of the heat exchanger 3 and on the other hand to an air intake face arranged in the cylinder head 2 of the internal combustion engine. The air intake face opens onto an air intake inlet in the cylinder head 2, making it possible to bring air to combustion chambers of the engine. This face extends substantially parallel to a longitudinal direction Y itself parallel to the axis of rotation of a camshaft of the engine, and substantially parallel to a vertical direction Z orthogonal to the longitudinal direction Y and to a transverse direction X.The transverse direction X extends orthogonally to the vertical Z and longitudinal Y directions, being substantially parallel to the direction of air flow through the air intake face of the cylinder head 2.

[0036] The air sent through the heat exchanger 3 and then the fixing device 1 to arrive at the air intake inlet in the cylinder head 2, comes from an intake pipe 7 connected by a connection 6 to a throttle body 5 comprising a butterfly valve controlled by a control unit. The butterfly valve makes it possible to modulate the air pressure at the inlet of an air inlet box 4 to which the valve is connected, this air inlet box 4 allowing the air to be sent from the outlet of the butterfly valve to an air inlet of the heat exchanger 3. The air inlet box 4 therefore comprises an air outlet face connected to the air inlet of the heat exchanger 3, which comprises an air outlet connected to a first air inlet face 30 (referenced in particular as figure 4) of the fixing device 1, a second air outlet face 32 (referenced in particular as figure 4) of the fixing device 1 being connected to the air intake face of the cylinder head 2.All these faces are substantially parallel to each other and therefore to the longitudinal Y and vertical Z directions.

[0037] As shown in Figure 2, the fixing device 1 has the overall shape of a frame comprising four walls delimiting an opening 12 of the fixing device 1, the air arriving in the opening 12 via the first face 30 of the fixing device 1, and leaving the opening 12 via the second face 32 of the fixing device 1, opposite the first face 30, the first and second faces 30, 32 being substantially orthogonal to the four walls.

[0038] In this embodiment of the invention, the heat exchanger 3 is metallic, for example made of aluminum, and comprises metal tabs folded over a rim of the fixing device 1 to connect to the latter, the rim delimiting the first air inlet face 30 of the fixing device 1. The heat exchanger 3 also comprises metal tabs folded over a rim of the air inlet box 4 to connect to the latter.

[0039] The fixing device 1 comprises a lower wall 16 substantially parallel to the longitudinal Y and transverse X directions. Depending on the inclination of the vehicle when it is parked on a slope in particular, this lower wall 16 is likely to comprise a retention zone 14 for oil or water condensates.

[0040] In order to prevent these liquids from pouring directly into the engine air intake when the vehicle restarts and returns to a less inclined position than when it was parked, the fixing device 1 according to the invention comprises means for holding these liquids in the retention zone 14, these holding means being, in this embodiment of the invention, a rib 18 shown in Figure 3. The fixing device i being, in this embodiment, made of molded synthetic material, the rib 18 is formed by molding.

[0041] This rib 18 circumscribes the retention zone 14 which extends below the heat exchanger 3, so as to maintain the humidity of the air leaving the heat exchanger 3 when this humidity condenses and flows over the lower wall 16. The rib 18 therefore comprises two arms 181, 182 substantially parallel to the transverse direction X and therefore to the direction of air flow, these arms 181, 182 each being connected at one of their ends by a branch 183 substantially parallel to the longitudinal direction Y, this branch 183 being proximal to the second face 32 of the device relative to the other ends of these arms 181, 182. These other ends are each located at a separate end of an intersection between the lower wall 16 and an air outlet face of the heat exchanger 3, and / or between the lower wall 16 and a modification of the slope of the lower wall 16.

[0042] Indeed, as shown in Figure 4, the lower wall 16 has a receiving surface 162 of the heat exchanger 3, proximal to the first face 30 and inclined relative to the remainder 164 of the lower wall 16. The arms 181, 182 of the rib 18 therefore begin outside this receiving surface 162, the remainder 164 of the lower wall 16 between the two arms 181, 182 and the branch 183 of the rib 18 forming the retention zone 14 at the outlet of the heat exchanger 3.

[0043] As can be seen in particular in Figure 5, the fixing device 1 comprises, molded in hollow on its second face 32, a passage 20 for gas resulting from oil vapors coming from a distribution channel for gas resulting from oil vapors arranged in the cylinder head 2 and emerging from the latter through a dedicated opening 8. This passage 20 is delimited by an edge 31 of the lower wall 16 extending over the second face 32, by rims also extending over the second face 32 and intended to receive a seal 26, and by outlet orifices 22, 24 also arranged on the second face 32. These outlet orifices 22, 24 allow the gas resulting from oil vapors coming from the cylinder head 2 of the engine to exit into the opening 12 of the fixing device 1.

[0044] Thus, when the air intake face of the cylinder head 2 is fixed to the second face 32 of the fixing device 1, in particular by means of screws passing through screw passages 28 arranged on a periphery of the second face 32, the cylinder head 2 closes the passage 20 while nevertheless allowing the gas resulting from oil vapors leaving the cylinder head 2 through the dedicated opening 8 to circulate through the passage 20. The gas resulting from oil vapors then arrives in the opening 12 of the fixing device 1 through the outlet orifices 22, 24 and can enter a plenum of the engine. The seal 26 makes it possible to prevent any escape of air or gas resulting from oil vapors outside the fixing device 1 or the cylinder head 2.

[0045] The outlet orifices 22, 24 are arranged in the lower wall 16 but outside the retention zone 14. Thus, the condensates retained in the retention zone 14 by the rib 18 cannot flow directly into the so-called “blow by” cavity of the cylinder head.

[0046] The rib 18 nevertheless comprises evacuation zones 34 (referenced in particular figures 4 and 6) for the liquid overflowing from the retention zone 14. These evacuation zones 34 allow the excess liquid to be evacuated gradually and without entering the intake ducts of the cylinder head 12. In particular, they are located close to the outlet orifices 22, 24 to allow the excess liquid to fall into the passage 20 and thus prevent it from entering the combustion chambers of the engine.

[0047] As shown in Figure 6, these evacuation zones 34 are produced by a height hi of the rib 18, lower at the level of each evacuation zone 34 than the height h2 of the rib outside these evacuation zones 34.

[0048] Figure 7 shows an enlargement of the second face 32 at the outlet orifice 22, in order to clarify the respective arrangement of the discharge zones 34 and the outlet orifices 22, 24. The outlet orifice 22 adjoins the rib 18 at the discharge zone 34. Guide means, constituted in this embodiment by flanges 36 on each side of the outlet orifice 22, guide the excess liquid passing over the rib 18 in the discharge zone, towards the outlet orifice 22.

[0049] The evacuation zone 34 being delimited by a portion of the rib 18 having a height hi lower than the height h2, the edges 36 therefore each extend in the transverse direction X from a separate end of the portion of rib delimiting the evacuation zone 34, up to the second face 32 therefore up to a surface intended to be in contact with the cylinder head 12.

[0050] The outlet orifices 22, 24 as well as the associated discharge zones 34 are symmetrical with respect to a plane of symmetry of the rib 18 extending in the transverse X and vertical Z directions, and are distributed regularly along the rib 18. The outlet orifices 22, 24 are in particular spaced apart from each other so as to uniformly distribute the gas from the oil vapors entering the plenum of the engine.

[0051] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, more than two outlet orifices, or only one, are for example arranged on the lower wall 16. In addition, the outlet orifices 22, 24 are, in an alternative embodiment of the invention, offset relative to the evacuation zones 34, the guide means then being ribs forming real conduits between the evacuation zones 34 and the outlet orifices 22, 24. The term “offset” is understood to mean a positioning of the evacuation zones 34 substantially in line with the outlet orifices 22, 24, in particular above the outlet orifices 22, 24, such that an evacuation zone is connected to an outlet orifice via a conduit produced by said guide means 36.

Claims

CLAIMS 1- Device for fixing (i) a heat exchanger (3) to a cylinder head (2) of an internal combustion engine, the fixing device (1) comprising an opening (12) capable of being passed through by air coming from the heat exchanger (3) and heading towards an air intake inlet arranged in the cylinder head (2), the fixing device (1) being characterized in that it comprises at least one retention zone (14), and means for maintaining a liquid present in the retention zone (14). 2- Fixing device (1) according to claim 1, in which the holding means comprise a rib (18) projecting from a lower wall (16) of the opening (12). 3- Fixing device (1) according to claim 1 or 2, wherein the fixing device (1) comprises a passage (20) for gas from oil vapors coming from an oil vapor gas distribution channel arranged in the cylinder head (2), the passage (20) comprising at least one outlet orifice (22, 24) for the gas formed in the lower wall (16) and a connection with the distribution channel, the outlet orifice (22, 24) being arranged outside the retention zone (14). 4- Fixing device (1) according to claim 3, in which the rib (18) comprises at least one evacuation zone (34) for liquid overflowing from the retention zone (14). 5- Fixing device (1) according to claim 4, in which the rib (18) has a first height (hi) at the level of the evacuation zone (34), and a second height (I12) on the rest of its periphery, higher than the first height (hi). 6- Fixing device (1) according to claim 4 or 5, comprising guide means (36) capable of directing liquid leaving the evacuation zone (34) towards the outlet orifice (22, 24). 7- Fixing device (i) according to claim 6, in which the guide means (36) form a channel extending from the discharge zone (34) to the outlet orifice (22, 24). 8- Fixing device (1) according to claim 6, in which the outlet orifice (22, 24) adjoins the rib (18) at the level of the evacuation zone (34), and in which the guide means (63) form edges of the outlet orifice (22, 24). 9- Fixing device (1) according to any one of claims 6 to 8, in which the fixing device (1) comprises several outlet orifices (22, 24), distributed along the rib (18), the rib (18) comprising as many evacuation zones (34) as outlet orifices (22, 24), each outlet orifice (22, 24) adjoining one of the evacuation zones (34) and being bordered by guide means (36) capable of channeling the liquid leaving the evacuation zone (34) to the outlet orifice (22, 24). 10- Arrangement comprising an internal combustion engine, a heat exchanger (3) and a fixing device (1) according to any one of claims 1 to 9, connected in a sealed manner on the one hand to a cylinder head (2) of the internal combustion engine and on the other hand to the heat exchanger (3). 11- Assembly comprising a heat exchanger (3), an air inlet box (4) capable of being connected to an air inlet of the heat exchanger (3), and a fixing device (1) according to any one of claims 1 to 9 capable of being connected to an air outlet of the heat exchanger (3).

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