Heat shield for a road vehicle equipped with an internal combustion engine and corresponding road vehicle

Abstract

Heat shield (12) for a road vehicle (1) equipped with an internal combustion engine (4); wherein the heat shield (12) is provided with at least one plate (14), comprising: an inner reflective layer (18) which, when in use, is to be oriented towards a heat source and is made of metallic material to reflect the thermal radiation; and an outer structural layer (20) opposite the inner layer (18), which is to be oriented away from the heat source during use and is made of composite material, preferably carbon fibers; The heat shield (12) is characterized in that the plate comprises an insulating intermediate layer (19) which is arranged between the inner reflective layer (18) and the outer structural layer (20) and is made of heat-insulating material, preferably aerogel.

Description

AREA OF INVENTION

[0001] The present invention relates to a heat shield (i.e., a heat protection device) for a road vehicle equipped with an internal combustion engine.

[0002] The present invention further relates to a road vehicle equipped with an internal combustion engine and provided with a heat shield (or a heat protection device).

[0003] The present invention finds advantageous application in a passenger car (PKW), to which the following disclosure expressly refers, without, however, losing any general validity. STATE OF THE ART

[0004] In a passenger car equipped with an internal combustion engine, it is generally known to shield the hottest components (such as the initial section of the exhaust system) with heat shields to prevent the emitted heat from overheating and damaging other nearby and heat-sensitive components.

[0005] Particularly with the constant increase in the installation density of components in modern passenger cars (especially in modern high-performance sports cars), the need is growing for a heat shield that is able to effectively shield the hottest components while being sufficiently rigid to avoid excessive vibrations during operation (too much vibration can affect both the heat shield and the surrounding components over time) and having a low weight so as not to significantly increase the overall weight of the passenger car.

[0006] Patent US4085816A describes a heat shield surrounding an exhaust pipe of an internal combustion engine to provide a certain thickness of insulating air layer between the heat shield and the exhaust pipe.

[0007] Patent application DE2819371A1 describes a heat shield for the exhaust pipe of a passenger car.

[0008] Patents US5080949A, US5280142A, DE19836970C2 and US6663171B2 describe different heat shield types for a component of the exhaust system.

[0009] Patent EP1955886B1 describes a motor vehicle equipped with an internal combustion engine and a heat shield positioned between the exhaust system and a heat-sensitive component located near the exhaust system. A ventilation device is provided that directs cooling air to the component, at least while the vehicle is in motion, to ensure a constant air exchange in the cold space where the component is located.

[0010] Patent application DE102013113213A1 describes a heat shield for a passenger car equipped with an internal combustion engine; the heat shield comprises a load-bearing layer made of composite material (in particular carbon fibers) and a reflective metal layer for reflecting heat radiation.

[0011] Patent application DE10332924A1 describes a heat shield for a passenger car equipped with an internal combustion engine; the heat shield has a box-shaped form and surrounds a section of the exhaust system. DESCRIPTION OF THE INVENTION

[0012] The present invention is therefore based on the objective of providing a heat shield (or a heat protection device) for a road vehicle equipped with an internal combustion engine, which has a high heat protection effect, is sufficiently rigid and has a low weight.

[0013] Another object of the present invention is to provide a road vehicle equipped with an internal combustion engine which is provided with a heat shield (i.e. a heat protection device) wherein the heat shield has a high heat shielding effect, is sufficiently rigid and has a low weight.

[0014] According to the invention, a heat shield for a road vehicle equipped with an internal combustion engine and a road vehicle equipped with an internal combustion engine with a heat shield are provided, according to the attached claims.

[0015] The claims describe preferred embodiments of the present invention and form an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will now be described with reference to the accompanying drawings, which illustrate an exemplary embodiment without limiting effect. The drawings show: • Fig. 1 a schematic view of a passenger car equipped with an internal combustion engine and fitted with a heat shield; • Fig. 2 A schematic cross-sectional view of a central section of a heat shield plate in Fig. 1; and • Fig. 3 A schematic cross-sectional view of an end section of a heat shield plate in Fig. 1. PREFERRED FORMS OF THE INVENTION

[0017] In Fig. Reference numeral 1 designates a passenger car in its entirety, comprising a frame that carries a pair of front wheels (or non-driven wheels) 2 and a pair of rear drive wheels 3. A combustion engine 4 is arranged in a central position within an engine compartment, generating torque that is transmitted to the rear drive wheels 3 via a transmission 5; in another embodiment not shown, the combustion engine 4 could be arranged in a rear or front position.

[0018] The frame is covered with a body enclosing a vehicle interior located between the front wheels 2 and the rear wheels 3, and equipped with (at least) two seats, each suitable for accommodating a corresponding occupant; the vehicle interior always provides space for a driver and possibly (at least) one occupant (who is, of course, optional).

[0019] The internal combustion engine 4 comprises an engine block 6 in which a plurality of cylinders 7 are present; in which in Fig. In the embodiment shown in Figure 1, six cylinders 7 are arranged in a row, but in other embodiments not shown, the number and / or arrangement of the cylinders 7 could be different (for example, four cylinders 7 arranged in a row or six or eight cylinders 7 in a V-arrangement).

[0020] The internal combustion engine 4 includes an exhaust system 8 designed to treat the exhaust gases produced during combustion by reducing acoustic and atmospheric emissions and improving the efficiency and performance of the internal combustion engine 4. Specifically, the exhaust system 8 includes (at least) an exhaust manifold 9 connected to the engine block 6 to collect the exhaust gases from the cylinders 7, and (at least) an exhaust port 10 extending from the exhaust manifold 9 and terminating in a silencer 11 located at the rear. Although for the sake of simplicity they are referred to as Fig. Not shown in Figure 1, treatment devices are arranged along the outlet channel to reduce pollutant emissions (i.e., one or more catalysts and, if necessary, a particulate filter), and the turbine of a turbocharger may also be arranged.

[0021] Part of the exhaust system 8 is partially surrounded by a heat shield 12 (i.e., a heat protection device) that separates the exhaust system 8 (which is the hottest part of the internal combustion engine 4) from other heat-sensitive components 13 of the internal combustion engine 4 or the passenger car 1. These components are sensitive to heat and therefore must not be heated above a certain temperature limit. They are located near the exhaust system 8. For example, the heat-sensitive components 13 may include one or more electronic control units or a lubricating oil reservoir.

[0022] In the Fig. In the embodiment shown in Figure 1, the heat shield 12 at least partially surrounds the exhaust manifold 9 of the exhaust system 8; according to other embodiments not shown, the heat shield 12 could at least partially surround other parts of the exhaust system 8.

[0023] In other words, the heat shield 12 is designed to protect the heat-sensitive components 13, which are sensitive to heat and therefore must not be heated above a certain temperature limit and are located near the combustion engine 4 (and in particular near the exhaust system 8) in order to optimize space utilization, from the heat emitted by the combustion engine 4 (and in particular by the exhaust system 8, which is the hottest part of the combustion engine 4).

[0024] The heat shield 12 separates a warm chamber, containing the exhaust manifold 9 of the exhaust system 8, from a cold chamber (or colder than the warm chamber), containing the heat-sensitive components 13. The air in the cold chamber acts as an insulator, slowing down heat transfer from the warm chamber through the cold chamber to the heat-sensitive components 13. To further reduce heat transfer to the heat-sensitive components 13 (or to cool them), a ventilation system 15 (preferably passive, i.e., without moving parts) is provided to circulate cooling air in the cold chamber. The ventilation device 15 is preferably passive and therefore utilizes the forward motion of the car 1 to generate a flow of cooling air that passes through the cold chamber.In particular, the ventilation device 15 comprises an air inlet 16 formed through the body (for example, a NACA air inlet) through which outside air is directed towards the cold space, and an air outlet 17 formed through the body through which the air that has flowed through the cold space exits to the outside.

[0025] The heat shield 12 comprises a plurality of plates 14 which are assembled together to form a box-shaped structure in the interior of which at least partially the exhaust manifold 9 of the exhaust system 8 is arranged; or the box-shaped structure formed from several plates 14 assembled together contains at least partially the exhaust manifold 9 of the exhaust system 8 within it.

[0026] According to a preferred embodiment, the plates 14 of the heat shield 12 are not connected to each other, but merely abutted; or the plates 14 of the heat shield 12 are attached to the engine block 6 or to other parts of the passenger car 1 in such a way that they abut each other to form the box-shaped structure in the interior of which at least part of the exhaust manifold 9 of the exhaust system 8 is arranged. However, the plates 14 of the heat shield 12 are not directly connected to each other, since the heat shield 12 is intended to provide thermal protection but does not need to ensure a tight seal.

[0027] As in the Fig. 2 and Fig. As shown in Figure 3, each plate 14 of the heat shield 12 comprises an inner reflective layer 18 (oriented towards the warm space and thus towards the exhaust system 8), which is made of a metallic material and serves primarily to reflect the thermal radiation emanating from the exhaust system 8; or, the inner reflective layer 18 reflects (sends) a portion of the incident (infrared) thermal radiation back instead of absorbing it (this phenomenon occurs when a material possesses properties that allow it to reflect thermal energy instead of converting it into internal heat). Preferably, the inner reflective layer 18 of each plate 14 is made of aluminum or stainless steel (optionally coated externally with a glossy aluminum foil exhibiting high reflectivity).Preferably, the inner reflective layer 18 of each plate 14 has a thickness of 0.2 to 0.5 mm (generally it is thinner when stainless steel is used, while it is thicker when aluminium is used).

[0028] Furthermore, each plate 14 of the heat shield 12 comprises an insulating intermediate layer 19 made of a heat-insulating material, preferably one with high insulating capacity. Preferably, the insulating intermediate layer 19 of each plate 14 is made of aerogel. Preferably, the insulating intermediate layer 19 of each plate 14 has a thickness of 3 to 4 mm.

[0029] Finally, each panel 14 of the heat shield 12 comprises an outer structural layer 20 (oriented towards the cold space and thus towards the heat-sensitive components 13 and on the opposite side of the exhaust system 8) made of a composite material containing a resin capable of withstanding high temperatures (at least up to 350 °C). The function of the outer structural layer 20 is to provide mechanical strength and stiffness to the panel 14, as it supports the weight of the panel 14 and ensures its stability. Preferably, the outer structural layer 20 of each panel 14 is made of carbon fibers. Preferably, the outer structural layer 20 of each panel 14 has a thickness of 1 to 1.5 mm.

[0030] From the above description it is clear that in each plate 14 of the heat shield 12 the insulating intermediate layer 19 is arranged between the inner reflective layer 18 and the outer structural layer 20.

[0031] According to a preferred embodiment, in each plate 14 of the heat shield 12, the insulating intermediate layer 19 is only laid (connected) on one side and not attached to the inner reflective layer 18, and on the other side is only laid and not attached (connected) to the outer structural layer 20.

[0032] Overall, each plate 14 of the heat shield 12 has a thickness of 4.2 to 5.7 mm.

[0033] According to a preferred embodiment, the outer structural layer 20 has a thickness that corresponds to 2.5 to 6 times the thickness of the inner reflective layer 18.

[0034] According to a preferred embodiment, the insulating intermediate layer 19 has a thickness that corresponds to 2 to 4 times the thickness of the outer structural layer 20.

[0035] According to a preferred embodiment, the insulating intermediate layer 19 has a thickness that corresponds to 6 to 20 times the thickness of the inner reflective layer 18.

[0036] According to a preferred embodiment, which is in Fig. As shown in Figure 3, the inner reflective layer 18 is bent in a U-shape along an outer edge of each plate 14 of the heat shield 12 to encompass a strip of the outer structural layer 20 and to receive (enclose) the insulating intermediate layer 19. Preferably, the end of the inner reflective layer 18 that is bent towards the outer structural layer 20 is attached to the outer structural layer 20, preferably by bonding (using a heat-resistant adhesive). According to an alternative embodiment, the end of the inner reflective layer 18 that is bent towards the outer structural layer 20 is merely placed on the outer structural layer 20 (neither bonded nor otherwise attached).In this way, the inner reflective layer 18 fulfills two functions: it holds the three layers 18, 19, and 20 pressed together and seals the insulating intermediate layer 19 between the inner reflective layer 18 and the outer structural layer 20, thus preventing the insulating intermediate layer 19 from releasing dust (or similar substances) from the plate 14 to the outside. In other words, to manufacture each plate 14 of the heat shield 12 in a "clean" manner, the intermediate layer 19 between the inner reflective layer 18 and the outer structural layer 20 is encapsulated, with the inner reflective layer 18 being successively bent (and, if necessary, glued or otherwise attached) onto the outer structural layer 20.

[0037] According to one possible embodiment, which is in Fig.As shown in Figure 2, a plate 14 of the heat shield 12 could include one or more mechanical fasteners 21 in the center, which serve to hold the three layers 18, 19 and 20 pressed together. For example, the mechanical fasteners 21 could be rivets or bolts (each consisting of a male element, or screw, and a female element, or nut).

[0038] In the embodiment shown in the accompanying figures, the heat shield 12 is used to shield the heat emanating from the exhaust system 8 (and in particular from the exhaust manifold 9 of the exhaust system 8); according to other embodiments not shown, the heat shield 12 is used to shield the heat emanating from other components of the internal combustion engine 4 that differ from the exhaust system 8.

[0039] In the embodiment shown in the accompanying figures, the heat shield 12 is used in a passenger car 1; according to other embodiments not shown, the heat shield 12 is used in a road vehicle 1 that is not a passenger car (for example, a truck, a bus, a motorcycle, or a work vehicle). According to further embodiments not shown, the heat shield 12 is used in a non-road vehicle (such as an aircraft or a watercraft).

[0040] The embodiments described here can be combined with each other.

[0041] The heat shield 12 described above offers numerous advantages.

[0042] Primarily, the heat shield 12 described above is particularly effective at shielding heat, or rather, it has a very low thermal conductivity.

[0043] Furthermore, the heat shield 12 described above is particularly light, since in each plate 14 only the inner reflective layer 18 has a high density (specific gravity) (especially if it is made of stainless steel), but it also has a very low thickness; instead, both the insulating intermediate layer 19 and the outer structural layer 20 have a very low density (specific gravity).

[0044] Finally, the heat shield 12 described above has a high mechanical stiffness, since in each plate 14 the outer structural layer 20 made of composite material makes it possible to achieve high mechanical stiffness values.

[0045] It is important to emphasize that the plates 14 of the heat shield 12, due to their low weight, tend to vibrate in a controlled manner, which is why it is sufficient to ensure a high, though not very high, mechanical stiffness to avoid any problems arising from the vibrations.

[0046] In summary, the plates 14 of the heat shield 12, being formed in the outer structural layer 20 from carbon fiber composite material, have a reduced weight and exhibit high and excellent vibration resistance.

[0047] The present innovation relates in particular to a heat shield 12 for a road vehicle 1 equipped with an internal combustion engine 4, which is provided with at least one plate 14, comprising: an inner reflective layer 18, which is to be oriented towards a heat source during use and is made of metallic material in order to reflect the heat radiation; an outer structural layer 20 opposite the inner layer 18, which is to be oriented away from the heat source during use and is made of composite material; and an insulating intermediate layer 19, which is arranged between the inner reflective layer 18 and the outer structural layer 20 and is made of heat-insulating material. LIST OF FIGURE REFERENCE MARKS 1 passenger car (car) 2 front wheels 3 rear wheels 4 Internal combustion engine 5 gearboxes 6 Engine block 7 cylinders 8 Exhaust system 9 exhaust manifolds 10 Outlet channel 11 silencers 12 Heat shield 13 heat-sensitive components 14 plates 15 Ventilation system 16 Air intake 17 Outlet 18 inner layer 19 Intermediate shift 20 outer layer 21 rivets QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 4085816A

[0006] DE 2819371A1

[0007] US 5080949A

[0008] US 5280142A

[0008] DE 19836970C2

[0008] US 6663171B2

[0008] EP 1955886B1

[0009] DE 102013113213A1

[0010] DE 10332924A1

[0011]

Claims

[1] Heat shield (12) for a road vehicle (1) equipped with an internal combustion engine (4); wherein the heat shield (12) is provided with at least one plate (14), comprising: an inner reflective layer (18) which, when in use, is to be oriented towards a heat source and is made of metallic material to reflect the thermal radiation; and an outer structural layer (20) opposite the inner layer (18), which is to be oriented away from the heat source during use and is made of composite material, preferably carbon fibers; the heat shield (12) is characterized by , that the plate comprises an insulating intermediate layer (19) arranged between the inner reflective layer (18) and the outer structural layer (20) and is made of heat-insulating material, preferably aerogel. [2] Heat shield (12) according to claim 1, wherein the insulating intermediate layer (19) is only applied and not attached to the inner reflective layer (18) on one side and is only applied and not attached to the outer structural layer (20) on the opposite side. [3] Heat shield (12) according to claim 1 or 2, wherein: the inner reflective layer (18) has a thickness of 0.2 to 0.5 mm; the insulating intermediate layer (19) has a thickness of 3 to 4 mm; and the outer structural layer (20) has a thickness of 1 to 1.5 mm. [4] Heat shield (12) according to claim 1, 2 or 3, wherein along an outer edge of the plate (14) the inner reflective layer (18) is bent in a U-shape to enclose a strip of the structural outer layer (20) and to accommodate the insulating intermediate layer (19). [5] Heat shield (12) according to claim 4, wherein an end of the inner reflective layer (18) is bent towards the structural outer layer (20) and attached to the structural outer layer (20), preferably bonded. [6] Heat shield (12) according to any one of claims 1 to 5, wherein the plate (14) comprises at least one mechanical connecting element (21) in the center, in particular a rivet or a bolt, which has the function of holding the three layers (18, 19, 20) pressed together. [7] Heat shield (12) according to any one of claims 1 to 6, wherein the outer structural layer (20) has a thickness corresponding to 2.5 to 6 times the thickness of the inner reflective layer (18). [8] Heat shield (12) according to any one of claims 1 to 7, wherein the insulating intermediate layer (19) has a thickness corresponding to 2 to 4 times the thickness of the structural outer layer (20). [9] Heat shield (12) according to any one of claims 1 to 8, wherein the insulating intermediate layer (19) has a thickness corresponding to 6 to 20 times the thickness of the inner reflective layer (18). [10] Road vehicle (1) comprising: an internal combustion engine (4) which is equipped with an exhaust system (8); at least one heat-sensitive component (13); and a heat shield (12) which is arranged between a hot part of the internal combustion engine (4) and the heat-sensitive component (13) and is designed according to one of claims 1 to 9. [11] Road vehicle (1) according to claim 10, wherein the heat shield (12) surrounds part of the exhaust system (8). [12] Road vehicle (1) according to claim 11, wherein: the internal combustion engine (4) comprises an engine block (6) having a plurality of cylinders (7); the exhaust system (8) includes an exhaust manifold (9) which is connected to the engine block (6) to collect the exhaust gases from the cylinders (7); and the heat shield (12) at least partially surrounds the exhaust manifold (9). [13] Road vehicle (1) according to claim 11 or 12, wherein: the heat shield (12) separates a warm space, in which at least part of the exhaust system (8) is located, from a cold space, in which the heat-sensitive component 13 is located; and a ventilation system (15) is provided which circulates cooling air in the cold room. [14] Road vehicle (1) according to claim 13, wherein the ventilation system (15) comprises an air inlet (16) formed through the body of the road vehicle (1) through which outside air is directed into the cold space, and an outlet (17) formed through the body of the road vehicle (1) through which the air that has flowed through the cold space exits to the outside. [15] Road vehicle (1) according to one of claims 11 to 14, wherein the heat shield (12) comprises a plurality of plates (14) which are assembled together to form a box-shaped structure, inside of which at least a part of the exhaust system (8) is arranged. [16] Road vehicle (1) according to claim 15, wherein: the plates (14) of the heat shield (12) are attached to an engine block (6) of the internal combustion engine (4) or to other parts of the road vehicle (1) in such a way that they abut each other to form the box-shaped structure; and the plates (14) of the heat shield (12) are not connected to each other, but only rest against each other.

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