Motor vehicle with underbody paneling provided in the rear area

Abstract

Motor vehicle (1) with an underbody panel (14) provided in the rear area, which is arranged below at least one rear silencer (20) of an exhaust system (2), wherein the at least one rear silencer (20) is provided with at least one exhaust outlet (24, 26) which has at least one exhaust tailpipe (23, 23', 25, 25') leading from the rear silencer (20) to the rear of the vehicle (11), and wherein the underbody panel (14) is provided with at least one air inlet (15, 16) through which air (L1, L2) flowing under the motor vehicle is directed into an area (13) above the underbody panel (14), characterized in that the at least one exhaust outlet (24, 26) is provided with at least one exhaust tailpipe baffle (27, 28) which at least partially surrounds the at least one exhaust tailpipe (23, 23', 25, 25') in its respective end section. and an airflow channel (29, 29') between the exhaust tailpipe (23, 23', 25, 25') and the exhaust tailpipe trim (27,28) forms a channel which is open to the area (13) above the underbody panel (14) and to the rear of the vehicle (11), wherein the airflow channel (29, 29') forms the air outlet from the area (13) above the underbody panel (14).

Description

TECHNICAL AREA

[0001] The invention relates to a motor vehicle with an underbody panel provided in the rear area according to the preamble of claim 1. BACKGROUND OF THE INVENTION

[0002] To optimize air resistance (represented by the parameter c) x ) as well as to reduce vehicle lift (represented by the indicator c) z In many cases, the use of a diffuser as underbody paneling in the rear of motor vehicles has proven advantageous. In most cases, the diffuser, as a paneling component, covers as large an area as possible in the underbody of the vehicle's rear.

[0003] A well-designed diffuser has a positive effect on reducing the drag coefficient c. x of the vehicle and can simultaneously contribute to reducing the lift coefficient c z2to significantly reduce lift at the rear axle. This is particularly important when, due to the design or body shape, no further potential for improvement in achieving lift targets can be gained through the design of the outer skin.

[0004] In the rear of a vehicle equipped with an internal combustion engine are parts of the exhaust system, such as the muffler and the exhaust tailpipes. These parts become very hot during operation and therefore require sufficient cooling, which is usually provided by the airflow. However, a diffuser, as an underbody panel in the rear of the vehicle, shields the muffler from the airflow flowing under the vehicle. Cooling air can reach the muffler, for example, through a large opening in the diffuser in the area of ​​the muffler. However, such an opening for cooling the muffler also... x- and c z -Potential lost. The effectiveness of such cooling measures is usually low, so that the resulting temperatures in the exhaust system area, taking all optimization measures into account, are often just below the acceptable limits.

[0005] During driving, the airflow around the vehicle creates a low pressure level around the rear silencer and in the area of ​​the rear axle components. Under unfavorable conditions, this can lead to a backflow of hot exhaust gas exiting the tailpipes into this low-pressure area, for example, the area between the rear silencer and the underbody paneling. This occurs particularly with exhaust systems that have visible tailpipes. Such exhaust backflow results in further undesirable heat input into the rear of the vehicle. STATE OF THE ART

[0006] From DE 297 21 562 U1, an air deflection device in the rear area of ​​a motor vehicle for influencing the rear vortices is known. This air deflection device, designed as a channel, directs part of the air into the wake area behind the rear of the vehicle, while another part of the air is intended to flow rearward over a rear section shaped as a diffuser. The c x The advantage arises from the reduction of the rear base area, since the rear opening of the channel eliminates part of the rear base area.

[0007] From DE 199 61 316 A1, an air deflection device in the rear area of ​​a motor vehicle is known, which directs air flowing under the vehicle's underbody into an air collection housing. This air collection housing opens into an exhaust pipe baffle through which the exhaust pipes pass. The airflow directed through the airflow collection housing into the exhaust pipe baffle pushes the exhaust gases to the rear and is intended to prevent exhaust backflow.

[0008] EP 2 834 138 B1 describes a diffuser with an air inlet for the rear silencer. The diffuser is designed to completely cover the rear silencer and have an air inlet for cooling air behind it. For rear silencers with a large mounting height, a large recess is provided in the diffuser surface. However, this large opening causes the diffuser to lose [c]. x - and c z -Potential. The cooling air is primarily driven by a pressure differential into the space around the rear silencer, which is covered by the diffuser. After absorbing heat at the rear silencer, the heated cooling air should flow forward under the diffuser cover.

[0009] A plate-shaped air guide element proposed in EP 1 609 706 A2 is attached to the underside of a rear silencer for aerodynamic reasons and is intended to generate downforce at the rear of the vehicle.

[0010] In DE 10 2015 108 509 A1, an air guide is provided in the rear area of ​​a motor vehicle, which is intended to cool the rear silencer via an air intake opening in the vehicle underbody. The air introduced there flows around the rear silencer for cooling purposes and is discharged upwards or directly at the rear of the vehicle into an ambient area where negative pressure prevails.

[0011] US Patent 6,435,298 B1 shows and describes an underbody structure of a motor vehicle that is spaced apart from the underside of a longitudinally mounted muffler, allowing airflow to flow rearward through the resulting gap beneath the muffler. This airflow exits at the rear of the vehicle, thus cooling the underside of the muffler.

[0012] EP 3 300 938 A1 describes an air intake in the underbody, which is primarily intended for cooling components in the engine compartment.

[0013] DE 43 19 281 A1 deals primarily with the design of air intakes in the underbody and shows, for example, a NACA air intake. It describes a largely smooth underbody in which aerodynamically optimized air intakes are incorporated to draw cooling air for engine components. One specific design of the bodywork component relates to the rear of the vehicle and describes a diffuser with cooling air intakes. The potential cooling of a rear silencer is also mentioned.

[0014] German patent DE 102016 118 692 A1 describes and illustrates a vehicle with an underbody design that increases downforce. The vehicle is equipped with a diffuser in the lower rear section, which has two openings in the center, each for an exhaust tailpipe. Two air inlets are provided in the underbody paneling in the direction of travel, forward of these openings. Ambient air flowing beneath the vehicle can enter the space above the underbody paneling through these openings. This airflow exits through the openings in the diffuser, thereby increasing the downforce of the vehicle's rear against the road surface.

[0015] DE 10 2016 219 906 A1 shows and describes a motor vehicle with an underbody panel that has an air intake in the area of ​​the vehicle's center. Air flowing under the underbody panel can enter the space between the underbody panel and the vehicle underbody through this intake and flow rearward against the direction of travel. This air flows past the exhaust system, in particular past a rear silencer, cools it, and exits through a large opening at the rear of the vehicle.

[0016] German patent DE 102 32 807 A1 relates to an air guidance device for the underbody area of ​​a vehicle, in which a heating duct and a cooling duct are provided, separated from each other by a partition plate. The heating duct surrounds pipes of an exhaust system, allowing the air flowing through the heating duct to be warmed. The air guidance device makes it possible to selectively direct warm air from the heating duct or cold air from the cooling duct to selected vehicle components, such as a transmission. This is intended to bring the cold transmission up to operating temperature more quickly or to cool it as needed.

[0017] Cooling a rear silencer, especially a transversely mounted one, through a large cutout in the diffuser proves ineffective, as only a small amount of air flows in to cool the silencer under the prevailing airflow conditions at the rear of the vehicle. At the same time, the diffuser loses some of its cooling capacity.x - and c z -Advantage. Another disadvantage of the cutout in the diffuser is the negative pressure area created in the vicinity of the rear silencer. This negative pressure area can draw exhaust gas exiting the tailpipes back forward. This backflow of exhaust gas can lead to heating of the thermally stressed rear area.

[0018] The state-of-the-art solutions presented above each aim to solve individual problems of the airflow around the vehicle; that is, they relate either to a solution for component cooling or to a solution for preventing exhaust backflow.

[0019] Exhaust backflow is usually only discovered quite late, for example when the vehicle, still in the prototype stage, is driven on the road during the assembly validation phase. At this relatively late stage, there are usually very few solutions available. PRESENTATION OF THE INVENTION

[0020] The object of the present invention is to design a motor vehicle of the generic type in such a way that, despite improved lift and drag coefficients in the rear area, sufficient cooling of an exhaust system provided there is ensured.

[0021] This problem is solved by the features of claim 1.

[0022] A motor vehicle with an underbody panel provided in the rear area, which is arranged below at least one rear silencer of an exhaust system, wherein the at least one rear silencer is provided with at least one exhaust outlet which has at least one exhaust tailpipe leading from the rear silencer to the rear of the vehicle, and wherein the underbody panel is provided with at least one air inlet through which air flowing under the motor vehicle is directed into an area above the underbody panel, is characterized according to the invention in that the exhaust outlet is provided with at least one exhaust tailpipe baffle which at least partially surrounds the at least one exhaust tailpipe in its respective end section and which forms an airflow channel between the exhaust tailpipe and the exhaust tailpipe baffle, which is open to the area above the underbody panel and to the rear of the vehicle.the airflow duct forms the air outlet from the area above the underbody paneling. ADVANTAGES

[0023] Since the underbody panel according to the invention is largely closed below the rear silencer, no negative pressure zone is created in the area of ​​the rear silencer through which exhaust gases could be drawn back. The underbody panel is provided only with at least one air inlet through which air flowing rearward under the vehicle can enter, then strikes hot surface areas of the rear silencer and the exhaust tailpipe, and dissipates heat from there. The air outlet is formed by the airflow channel between the respective end section of the exhaust tailpipe and the exhaust tailpipe baffle. The air guided through the airflow channel formed between the exhaust tailpipe and the exhaust tailpipe baffle creates a bypass flow surrounding the exiting exhaust gas.In this way, a continuous, counter-directional airflow is generated in the space between the rear silencer and the underbody paneling while the vehicle is in motion, dissipating heat from this area. The dedicated inflow and outflow create a clearly directed flow that prevents hot exhaust gases exiting the tailpipe from being drawn back into the space between the rear silencer and the underbody paneling.

[0024] Further preferred and advantageous design features of the motor vehicle according to the invention are the subject of dependent claims 2 to 10.

[0025] It is also particularly advantageous if at least one air intake is designed or positioned in the underbody paneling in such a way that at least part of the airflow entering through the intake is directed towards at least one exhaust tailpipe. This design allows for targeted airflow to particularly hot parts of the exhaust tailpipe.

[0026] Preferably, at least one air intake is arranged in the direction of travel upstream of at least one exhaust tailpipe. This directs the incoming air directly onto the exhaust tailpipe.

[0027] In a preferred embodiment, which can be combined with other embodiments, the at least one air inlet is designed or arranged in the underbody panel such that at least part of the airflow entering through the air inlet is directed towards or along the underside of the at least one rear silencer. This variant allows for targeted airflow to particularly hot parts on the underside of the rear silencer.

[0028] In a further preferred embodiment, which can also be combined with other embodiments, the at least one air inlet is designed or arranged in the underbody panel such that at least part of the airflow entering through the air inlet is directed towards or along the top of the at least one rear silencer. This variant allows for targeted airflow to particularly hot parts on the top of the rear silencer.

[0029] Preferably, air guide devices are provided above or on the upper surface of the underbody paneling, which direct and steer at least a portion of the airflow entering through the at least one air inlet. This embodiment allows for targeted airflow to particularly hot parts of the exhaust system.

[0030] A particularly advantageous embodiment, which can also be combined with other embodiments, is one in which the rear silencer is installed transversely in the rear of the vehicle. In this embodiment, an exhaust outlet with at least one exhaust tailpipe connected to the rear silencer is provided on the left and / or right end face, and the at least one air inlet is arranged in the direction of travel exclusively in front of the at least one exhaust tailpipe.

[0031] In a preferred embodiment of the invention, in addition to the at least one air inlet arranged in the direction of travel upstream of the at least one exhaust tailpipe, at least one further upper air inlet is arranged in the direction of travel upstream of the air inlet. This enables targeted additional cooling of the rear silencer.

[0032] In an alternative embodiment, no air inlets other than the at least one air inlet located in front of the exhaust tailpipe are provided. This ensures that the air flowing rearward under the vehicle can only enter the space above the underbody panel forming the diffuser through this dedicated air inlet or – in the case of multiple air inlets – these dedicated air inlets, thus creating a predictable airflow.

[0033] It is also advantageous if, apart from the airflow duct assigned to at least one exhaust outlet, no further air outlet is provided in the area above the underbody paneling. This ensures that the air flowing rearward under the vehicle can only exit through this dedicated air outlet, or—in the case of multiple exhaust outlets—through these dedicated air outlets from the space above the underbody paneling that forms the diffuser, thus creating a predictable airflow and preventing exhaust backflow.

[0034] An embodiment is also advantageous in which the exhaust tailpipe baffle surrounding the respective airflow channel extends to the rear beyond the exhaust tailpipes and preferably has an outlet opening with a reduced diameter.

[0035] Preferred embodiments of the invention with additional design details and further advantages are described and explained in more detail below with reference to the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] It shows: Fig. 1 the rear of a motor vehicle according to the invention viewed obliquely from behind and from below; Fig. 2 a vertical longitudinal section through the rear of a motor vehicle according to the invention in a first variant and Fig. 3 a vertical longitudinal section through the rear of a motor vehicle according to the invention in a first variant. PRESENTATION OF PREFERRED EXECUTION EXAMPLES

[0037] In Fig. Figure 1 shows the rear of a motor vehicle 1 according to the invention in a view taken obliquely from behind and from below. A rear apron 12, which is part of the body of the vehicle 1, closes off the rear of the vehicle 10 at the bottom. An underbody panel 14 is provided on the underside of the rear of the vehicle 10, which is connected to the rear apron 12 and to a vehicle structure of the motor vehicle 1 (not shown) in a generally known manner, for example by screws.

[0038] Above the rear underbody panel 14, the motor vehicle 1 is equipped with a rear silencer 20 of an exhaust system 2 of the motor vehicle 1, extending in the transverse direction (Y-direction) of the vehicle. Exhaust pipes 22, 22', which come from an internal combustion engine (not shown) of the motor vehicle 1, are connected to the rear silencer 20 in a generally known manner. The rear silencer 20 is provided at its left end 20' and at its right end 20" with an exhaust outlet 24, 26, each of which has two exhaust tailpipes 23, 23' and 25, 25' respectively, which are fluidically connected to the interior of the rear silencer 20 and which lead from the respective end face 20', 20" of the rear silencer 20 to the rear of the vehicle 10 and exit there through corresponding openings 11, 11' in the rear apron 12 to the outside.

[0039] Each of the two exhaust outlets 24, 26 has an exhaust tailpipe baffle 27, 28 that surrounds the respective exhaust tailpipes 23, 23' and 25, 25' respectively in their respective end sections. The respective exhaust tailpipe baffle 27, 28 is attached to the vehicle structure or to the rear apron 12 or to the exhaust system and is spaced apart from the associated exhaust tailpipes 23, 23', 25, 25', so that an airflow channel 29, 29' is formed between the respective exhaust tailpipe baffle 27, 28 and the associated exhaust tailpipes 23, 23', 25, 25', which is open both forward in the direction of travel F and towards the rear of the vehicle. Even if the in Fig. As shown only by the right exhaust tailpipe trim 28, the respective exhaust tailpipe trim 27, 28 surrounds the associated exhaust tailpipes 23, 23', 25, 25', thus forming a tubular casing surrounding the exhaust tailpipes 23, 23', 25, 25'. In the direction of travel F forward, the respective airflow channel 29, 29' opens into a region 13 above the underbody panel 14 within the rear apron 12, in which the rear silencer 20 is also located. Towards the rear, the respective exhaust tailpipe trim 27, 28 extends beyond the ends of the exhaust tailpipes 23, 23', 25, 25', and the free cross-section of the exhaust tailpipes 27, 28 narrows towards their respective open rear ends, forming an outlet opening, as shown in Fig. 2 can be seen from the outlet opening 27'.

[0040] In the direction of travel F, in front of the respective exhaust outlet 24, 26, a ramp-like air inlet 15, 16 with a rearwardly rising ramp surface 15', 16' is provided in the front area 14' of the underbody panel 14, each leading to an associated opening 17, 18 in the underbody panel 14. The respective opening 17, 18 provides access to the area 13 above the underbody panel 14. In this way, air L1, L2 of the driving wind W flowing under the vehicle 1 can flow through the respective ramp-like air inlet 15, 16 into the area 13 above the underbody panel 14 through the respective associated opening 17, 18.

[0041] The air entering the area 13 above the underbody panel 14 via the ramp-like air inlets 15, 16 and the associated opening 17, 18 flows, as can be seen from the flow arrows in the figures, along the respective exhaust tailpipes 23, 23' and 25, 25' respectively, towards the rear, through the airflow channel 29, 29' formed between the exhaust tailpipe trim 27, 28 and the associated exhaust tailpipes 23, 23', 25, 25' and exits through the outlet opening 27' of the left exhaust tailpipe trim 27 ( Fig. 2) or through the not shown outlet opening of the right exhaust tailpipe trim 28, as indicated by the arrows L'1, L"1 and L'2, L"2 respectively in Fig. 1 is symbolically represented. This escaping air surrounds the exhaust jet A1, A2 exiting from the exhaust tailpipes 23, 23' and 25, 25' respectively, in the manner of a sheath flow.

[0042] Fig. Figure 2 shows a vertical longitudinal section through the rear of the motor vehicle 1 according to the invention. Fig. 1 in the area of ​​the left ramp-like air intake 15. There, the position of the rear silencer 20 can be seen in a space between a luggage compartment floor 10' of the vehicle 1 and the underbody paneling 14. Above the rear silencer 20 and in front of it in the direction of travel, a heat shield 21 is provided at a distance from it, which absorbs the heat radiation emanating from the rear silencer 20 and protects the luggage compartment floor 10' located above and in front of it from direct heat radiation. In Fig. Figure 2 also shows how the exhaust tailpipe trim 27 is arranged in the opening 11 of the rear apron 12 and surrounds the rear end of the exhaust tailpipes 23, 23'.

[0043] In Fig. 2 clearly shows how the part of the airflow W flowing under the vehicle 1 splits, with a part of it flowing as airflow L1 over the ramp-like air inlet 15 and through the opening 17 in the underbody panel 14 into the area 13 above the underbody panel 14 and there under the rear silencer 20 or along its front end 20' along the exhaust tailpipes 23, 23' towards the airflow channel 29 and out of this at the rear of the vehicle 10, surrounding the exhaust jet A1.

[0044] Part of the airflow L1 entering the area 13 through the opening 17 is deflected, for example by air guides (not shown), obliquely towards the center of the vehicle, towards the rear silencer 20 and flows around the rear silencer 20 counterclockwise. An upper airflow in the space 13' formed between the rear silencer 20 and the heat shield 21 flows forward in the direction of travel and then downwards, before rejoining the rearward-flowing airflow and exiting with it at the rear of the vehicle through the airflow channel 29, 29'. In this way, not only is the lateral area at the front end 20' of the rear silencer 20 with the exhaust tailpipes 23, 23' connected there cooled by the airflow, but also the outer circumference of the rear silencer 20.

[0045] The airflow around and cooling of the right exhaust outlet 26 by means of the air flowing through the right ramp-like air inlet 16 takes place in the same way and is therefore not described separately.

[0046] A slightly modified embodiment of the invention is described in Fig. Figure 3 shows the underbody panel 14 with its front end 14' (in the direction of travel F) positioned vertically in front of the respective ramp-like air inlet 15, 16, relative to the underbody 1' of the vehicle 1, thus forming an additional upper air inlet opening 19. A partial flow L3 of the airflow W flowing under the vehicle 1 enters the space 13' between the rear silencer 20 and the heat shield 21 through the upper air inlet opening 19. This air flows around the rear silencer 20 on its upper surface, against the direction of travel, before exiting at the rear of the vehicle through the airflow channel 29, 29'.

[0047] The remaining structure of the underbody paneling 14 with the ramp-like air inlets 15, 16 and the course of the airflow entering there, as well as the structure and arrangement of the respective exhaust tailpipes 23, 23', 25, 25' surrounding the exhaust tailpipe trim 27, 29, corresponds to the structure as it is in conjunction with Fig. 2 has been described. Even in this modified embodiment of the Fig. 3. The flow around and cooling of the right exhaust outlet 26 by means of the air flowing through the right ramp-like air inlet 16 takes place in the same way as on the left side and is therefore not described separately.

[0048] According to the exemplary embodiments of the invention shown in the figures, air inlet ramps in the form of ramp-like air inlets 15, 16 are located to the right and left in the direction of travel F in front of the end faces 20', 20" of the transverse rear silencer 20, namely where the highest temperatures in the rear silencer ("hot spots") are located. These air inlet ramps capture air from the underbody flow and direct it to the "hot spots" of the rear silencer 20 and the exhaust outlets 24, 26 that begin there for cooling.

[0049] The ramp surfaces 15', 16' of the air intake ramps act on both sides, meaning that part of the airflow is directed onto the underside of the rear silencer 20 and onto the exhaust tailpipes 23, 23', 25, 25' for cooling, and from there, after cooling, it is directed to the respective airflow channel 29, 29' surrounding the exhaust tailpipes within the exhaust tailpipe baffle 27, 29. The ends of the exhaust tailpipes 23, 23', 25, 25' are thus surrounded by the cooling air, so that no exhaust gas can flow back.

[0050] The upper part of the ramp surfaces 15', 16' of the air intake ramps is cooled from the front through the respective front opening 19, directing the cooling air upwards at the "hot spot" of the rear silencer 20. This cooling airflow flows through the space between the rear silencer 20 and the heat shield 21 under the luggage compartment floor 10'. This cooling airflow significantly reduces the temperature in this space, and measurements have confirmed a substantial decrease in the thermal load on the luggage compartment floor.

[0051] The underbody panel 14 according to the invention, which is also referred to as a diffuser, thus enables the solution of several problems of vehicle airflow in a single component. A largely closed diffuser is used for optimal c x - and c z-values ​​are created, and at the same time, improved cooling of the hot components of the exhaust system 2 is achieved, such as the rear silencer 20 and the exhaust tailpipes 23, 23', 25, 25'. The design of the cooling airflow allows a first part of the cooling airflow to cool the difficult-to-access space 13' between the rear silencer 20 and the heat shield 21, and a second part of the cooling airflow to cool the respective "hot spot" of the rear silencer 20 and the exhaust outlets 24, 26. Furthermore, after fulfilling its cooling task at the rear silencer 20, the second part of the cooling airflow is directed towards the respective exhaust tailpipe baffle 27, 28 in such a way that it is flushed with fresh air from the front, cooled, and a backflow of exhaust gas is prevented.This avoidance of exhaust gas backflow is important because hot exhaust gas flowing back under the underbody paneling can thermally damage components behind the rear apron and, in the case of minimal leaks in the underbody, can also lead to CO entering the vehicle interior while driving.

[0052] The invention is applicable to various forms of exhaust systems, i.e. in addition to the transverse rear silencer 20 shown in the illustrations, the invention can also be implemented with a rear silencer arranged individually (transversely, obliquely or longitudinally) for each side of the vehicle.

[0053] The invention is not limited to the above embodiment, which merely serves to generally illustrate the core concept of the invention. Within the scope of protection, the device according to the invention can also assume other embodiments than those described above. In particular, the device can have features that represent a combination of the respective individual features of the claims.

[0054] Reference numerals in the claims, description and drawings serve only to improve understanding of the invention and are not intended to limit the scope of protection. Reference symbol list 1 motor vehicle 1' Underbody of the motor vehicle 10 Vehicle rear 10' luggage compartment floor 11 Opening the rear bumper 11' Opening the rear bumper 12 Rear apron 13 Area above the underbody paneling 13' space between rear silencer and heat shield 14 Underbody paneling 14' front area of ​​the underbody paneling 15 left ramp-like air intake 15' ramp area 16 right ramp-like air intake 16' ramp area 17 Opening in the underbody paneling 18 Opening in the underbody paneling 20 rear silencers 20' left front end of the rear silencer 20" right front end of the rear silencer 21 Heat shielding plate 22 Exhaust pipe 22' exhaust pipe 23 Exhaust tailpipe 23' Exhaust tailpipe 24 Exhaust outlet 25 Exhaust tailpipe 25' exhaust tailpipe 26 Exhaust outlet 27 Exhaust tailpipe trim 27' Exit opening 28 Exhaust tailpipe trim 29 Airflow duct 29' Airflow duct A1 Exhaust jet A2 Exhaust jet F Direction of travel L1 Airflow L2 airflow L3 airflow W Wind Y Vehicle transverse direction

Claims

[1] Motor vehicle (1) with an underbody panel (14) provided in the rear region, which is arranged below at least one rear silencer (20) of an exhaust system (2), wherein the at least one rear silencer (20) is provided with at least one exhaust outlet (24, 26) which has at least one exhaust tailpipe (23, 23', 25, 25') leading from the rear silencer (20) to the rear of the vehicle (11), and wherein the underbody panel (14) is provided with at least one air inlet (15, 16) through which air (L1, L2) flowing under the motor vehicle is guided into a region (13) above the underbody panel (14), characterized byin that the at least one exhaust gas outlet (24, 26) is provided with at least one exhaust gas tailpipe cover (27, 28) which at least partially surrounds the at least one exhaust gas tailpipe (23, 23', 25, 25') in its respective end section and which forms an air flow channel (29, 29') between the exhaust gas tailpipe (23, 23', 25, 25') and the exhaust gas tailpipe cover (27, 28), which is open to the area (13) above the underbody paneling (14) and to the rear of the vehicle (11), wherein the air flow channel (29, 29') forms the air outlet from the area (13) above the underbody paneling (14). [2] Motor vehicle (1) according to claim 1, characterized by that the at least one air inlet (15, 16) is designed or arranged in the underbody paneling (14) in such a way that at least part of the air flow (L1, L2) flowing in through the air inlet (15, 16) is directed onto the at least one exhaust tailpipe (23, 23', 25, 25'). [3] Motor vehicle (1) according to claim 1 or 2, characterized by that the at least one air inlet (15, 16) is arranged in the direction of travel (F) in front of the at least one exhaust tailpipe (23, 23', 25, 25'). [4] Motor vehicle (1) according to one of the preceding claims, characterized by that the at least one air inlet (15, 16) is designed or arranged in the underbody paneling (14) in such a way that at least part of the air flow (L1, L2) flowing in through the air inlet (15, 16) is directed onto the underside of the at least one rear silencer (20) or along this underside. [5] Motor vehicle (1) according to one of the preceding claims, characterized by that the at least one air inlet (15, 16) is designed or arranged in the underbody paneling (14) in such a way that at least part of the air flow (L1, L2) flowing in through the air inlet (15, 16) is directed onto the upper side of the at least one rear silencer (20) or along this upper side. [6] Motor vehicle (1) according to one of the preceding claims, characterized by that air guiding devices are provided above the underbody paneling (14) or on its upper side, which align and direct at least part of the air flow (L1, L2) flowing in through the at least one air inlet (15, 16). [7] Motor vehicle (1) according to one of the preceding claims, characterized by , that the rear silencer (20) is installed transversely in the rear area of ​​the vehicle, that an exhaust gas outlet (24, 26) with at least one exhaust gas tailpipe (23, 23', 25, 25') connected to the rear silencer (20) is provided on the left and / or right end face (20', 20") of the rear silencer (20), and that the at least one air inlet (15, 16) is arranged in the direction of travel (F) exclusively in front of the at least one exhaust tailpipe (23, 23', 25, 25'). [8] Motor vehicle (1) according to one of the preceding claims, characterized by in that, in addition to the at least one air inlet (15, 16) arranged in front of the at least one exhaust tailpipe (23, 23', 25, 25') in the direction of travel (F), at least one further upper air inlet (19) is arranged in front of the air inlet (15, 16) in the direction of travel. [9] Motor vehicle (1) according to one of the preceding claims, characterized by that apart from the air flow channel (29, 29') associated with the at least one exhaust outlet (24, 26), no further air outlet is provided from the area (13) above the underbody paneling (14). [10] Motor vehicle (1) according to one of the preceding claims, characterized by that the exhaust tailpipe cover (27, 28) surrounding the respective air flow channel (29, 29') extends rearward beyond the exhaust tailpipes (23, 23', 25, 25') and preferably has an outlet opening (27') with a reduced diameter.

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