DE102016213231B4 - Rear diffuser for a motor vehicle, motor vehicle with a rear diffuser - Google Patents

Abstract

Rear diffuser (HD) for a motor vehicle (FZ), comprising: - at least one exhaust gas inflow opening (EO1) for receiving exhaust gas from an exhaust system (AA) of the motor vehicle (FZ); - at least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5 ) for releasing the exhaust gas in the form of an exhaust gas flow into the surroundings of the motor vehicle (FZ); - at least one exhaust gas flow channel (AK) between the at least one exhaust gas inflow opening (EO1) and the at least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5) - wherein the at least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5) for changing air turbulence at the vehicle rear (FH) of the motor vehicle (FZ) by the exhaust gas in a longitudinal direction (LR) of the motor vehicle (FZ) to the vehicle rear (FH ) is directed towards, characterized in that the rear diffuser (HD) further comprises at least one controllable / regulatable diaphragm (BL1, BL2, BL3, BL4, BL5) which is attached to the at least one exhaust gas outflow opening (AO1, AO2, A O3, AO4, AO5) is arranged and is set up to regulate the volume flow of the exhaust gas flow.

Description

The present invention relates to a rear diffuser for a motor vehicle and a motor vehicle with a rear diffuser mentioned.

It is known that air turbulence forms at the rear of a moving motor vehicle, which leads to a deterioration in the aerodynamics of the motor vehicle and thus to an increase in driving resistance and ultimately to an increase in fuel consumption.

A generic rear diffuser is for example in the document DE 10 2007 037 599 A1 disclosed.

Further rear diffusers are for example in the documents AT 512 808 A1 , DE 199 61 316 A1 and DE 10 2009 054 091 A1 disclosed.

The object of the present invention is to provide a way of reducing fuel consumption.

This object is achieved by the subjects of the independent claims. Advantageous refinements are the subject of the subclaims.

According to a first aspect of the invention, a rear diffuser for a motor vehicle is provided.

The rear diffuser comprises at least one exhaust gas inflow opening for receiving exhaust gas from an exhaust system of the motor vehicle and at least one exhaust gas outflow opening for discharging the exhaust gas into the surroundings of the motor vehicle.

The rear diffuser further comprises at least one exhaust gas flow channel which is arranged between the at least one exhaust gas inflow opening and the at least one exhaust gas outflow opening and is configured to guide the exhaust gas from the at least one exhaust gas inflow opening to the at least one exhaust gas outflow opening.

In this case, the at least one exhaust gas outflow opening for the (targeted) change in air turbulence at the rear of the motor vehicle by the exhaust gas is directed, for example, in a longitudinal direction of the motor vehicle towards the rear of the vehicle.

The invention is based on the idea that while the motor vehicle is in motion, air turbulence is created behind the vehicle behind the rear of the vehicle due to the formation of air turbulence, which, as part of the aerodynamic resistance, has a braking effect on the motor vehicle.

The shape and size of the air turbulence determine the degree of negative air pressure and thus the aerodynamic resistance. The smaller the air turbulence, the smaller the aerodynamic resistance.

In the context of the invention, it was recognized that a targeted blowing out of gas in the form of the local gas flow in the direction of flow and / or against the direction of flow and / or in the transverse direction, in the area behind the rear of the vehicle, reduces the formation of large air turbulences in this area can.

Based on these findings, the above-mentioned rear diffuser is proposed.

With this rear diffuser, in particular with the exhaust gas flow channel, the exhaust gas under excess pressure is passed on from the exhaust system of the motor vehicle to the exhaust gas outflow opening and from there discharged as exhaust gas flows (with excess pressure) into the area behind the rear of the vehicle.

These exhaust gas flows interrupt large-scale air turbulences which form in the area behind the rear of the vehicle and cause negative air pressure in the area behind the rear of the vehicle. As a result of the interruption, instead of large-scale air turbulence, comparatively smaller air turbulences are formed, which overall cause a lower negative air pressure.

This reduces the aerodynamic resistance that acts on the entire motor vehicle and thus improves the aerodynamics of the motor vehicle. As a result, the fuel consumption of the automobile is reduced.

By aligning the at least one exhaust gas outflow opening, for example, in the longitudinal direction and / or transverse direction of the motor vehicle to the rear of the vehicle, the exhaust gas emerging from this exhaust gas outflow opening can be specifically discharged into the area behind the rear of the vehicle where the large-scale air turbulence is formed.

This provides a possibility with which the fuel consumption of the motor vehicle can be reduced.

The rear diffuser according to the invention further comprises at least one controllable / regulatable screen which is attached to the at least one Exhaust gas outflow opening is arranged and is designed to regulate the volume flow of the exhaust gas flow.

The diaphragm is an element in the hydraulic system which changes the line cross-section of the at least one exhaust gas outflow opening and thus the flow resistance. A controllable / regulatable diaphragm is a diaphragm with a variable cross-sectional constriction, as in the case of an optical diaphragm, whereby the line cross-section of the at least one exhaust gas outflow opening and thus the volume flow of the exhaust gas flow can be regulated.

The rear diffuser preferably further comprises a controllable / regulatable compressor which is arranged in the at least one exhaust gas flow channel and is set up to regulate the pressure in the exhaust gas flow by compressing the exhaust gas. Alternatively, alternating compression / decompression of the exhaust gas can also take place, for example.

The rear diffuser preferably further comprises at least three exhaust gas outflow openings for discharging the exhaust gas into the surroundings of the motor vehicle, these being directed towards the rear of the vehicle in the longitudinal direction of the motor vehicle towards the rear of the vehicle and from one another in a transverse direction of the motor vehicle for the (targeted) change in the air turbulence at the rear of the vehicle by the exhaust gas are arranged spatially offset.

As an alternative or in addition to this, at least two of the at least three exhaust gas outflow openings are preferably arranged spatially offset from one another in the longitudinal direction of the motor vehicle. As a result, the exhaust gas outflow openings generate exhaust gas flows spatially offset from one another in the longitudinal direction at the rear of the vehicle.

As an alternative or in addition to this, at least two of the at least three exhaust gas outflow openings are preferably arranged spatially offset from one another in a vertical direction of the motor vehicle. As a result, the exhaust gas outflow openings generate exhaust gas flows that are spatially offset from one another in the vertical direction at the rear of the vehicle.

The at least three exhaust gas outflow openings each have a cross-sectional area, the cross-sectional areas of at least two of the at least three exhaust gas outflow openings preferably being of different sizes. As a result, the exhaust gas outflow openings generate exhaust gas flows spatially offset from one another in the transverse direction at the rear of the vehicle.

The at least one exhaust gas flow channel preferably has at least one channel section which is designed for sound attenuation in the exhaust gas. The at least one channel section has a wall which preferably has sound-absorbing, in particular elastic, material and / or a surface structure for sound-absorbing.

By using the sound-absorbing material or the surface structure for sound-absorbing, the function of a conventional silencer of an exhaust gas exhaust can be fulfilled.

The at least one exhaust gas flow channel preferably has a catalytic converter for exhaust gas aftertreatment.

The rear diffuser preferably further comprises at least one air guide vane for improving the aerodynamics of the motor vehicle, which is directed towards the rear of the vehicle in the longitudinal direction of the motor vehicle.

In this case, the at least one air guide vane, viewed in the transverse direction of the motor vehicle, is preferably arranged between two adjacent ones of the at least three of the exhaust gas outflow openings.

The rear diffuser preferably further comprises at least one air inflow opening for receiving air from the surroundings of the motor vehicle and at least one air flow channel between the at least one air inflow opening and the at least one exhaust gas flow channel, which is set up to supply the air received via the at least one air inflow opening to the at least one exhaust gas flow channel conduct.

The rear diffuser preferably further comprises at least one further compressor which is arranged in the at least one air flow channel and is set up to compress the air received by the at least one air inflow opening and to forward it (with more air pressure) to the adjoining at least one exhaust gas flow channel. The rear diffuser is preferably designed in one piece, in particular in a forming process, specifically in a casting process or in a 3-D printing process.

As a result of the one-piece formation, the rear diffuser combines the functions of soundproofing, improving aerodynamics and exhaust gas aftertreatment in a single vehicle component, which makes assembly of the motor vehicle easier and the production costs of the motor vehicle can be reduced.

According to a further aspect of the invention, a motor vehicle is provided. The motor vehicle comprises an exhaust system with at least one exhaust gas outflow opening for discharging the exhaust gas from an internal combustion engine of the motor vehicle and a rear diffuser described above, the rear diffuser being fluidically connected to the at least one exhaust gas outflow opening of the exhaust system via the at least one exhaust gas inflow opening.

Advantageous configurations of the rear diffuser described above, insofar as they are otherwise transferable to the above-mentioned motor vehicle, are also to be regarded as advantageous configurations of the motor vehicle.

• Im Folgenden wird eine beispielhafte Ausführungsform der Erfindung Bezug nehmend auf die beiliegende Zeichnung näher erläutert. Dabei zeigen:
  • 1 in einer schematischen Seitenansicht ein Kraftfahrzeug mit einem Heckdiffusor gemäß einer Ausführungsform der Erfindung;
  • 2 in einer schematischen Unteransicht einen Querschnitt des in der 1 dargestellten Heckdiffusors.

Brief description of the drawing:

• In the following, an exemplary embodiment of the invention is explained in more detail with reference to the accompanying drawing. Show:
  • 1 a schematic side view of a motor vehicle with a rear diffuser according to an embodiment of the invention;
  • 2 in a schematic bottom view a cross section of the in FIG 1 illustrated rear diffuser.

• Das Kraftfahrzeug FZ in 1 umfasst einen Verbrennungsmotor VM zum Antrieb des Kraftfahrzeugs FZ sowie eine Abgasanlage AA, welche an einem Abgastrakt des Verbrennungsmotors VM strömungstechnisch angeschlossen ist und eingerichtet ist, das Abgas des Verbrennungsmotors VM abzuführen.

Detailed description of the drawing:

• The car FZ in 1 includes an internal combustion engine VM to drive the motor vehicle FZ as well as an exhaust system AA , which on an exhaust tract of the internal combustion engine VM Is fluidically connected and is set up, the exhaust gas of the internal combustion engine VM to dissipate.

The car FZ further includes a rear diffuser HD , the one at the rear of the vehicle FH is solidified in the area of the underbody and via an exhaust gas inflow opening E01 with an exhaust gas outflow opening of the exhaust system AA is fluidically connected.

the 2 shows the rear diffuser in a schematic view from below HD .

The rear diffuser HD is formed in one piece in this embodiment from a plastic in a casting process or a 3-D printing process.

The rear diffuser HD includes an exhaust gas inflow opening E01 over which the rear diffuser HD with an exhaust gas outflow opening of the exhaust system AA is fluidically connected.

The rear diffuser HD further comprises an air inflow opening EO2 for sucking in air from the surroundings of the motor vehicle FZ .

The rear diffuser HD further comprises five exhaust gas outflow openings A01 , AO2 , AO3 , AO4 , AO5 , which on one of the rear of the vehicle FH facing end of the rear diffuser HD are trained. There are five exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 in the longitudinal direction LR, in the transverse direction QR and in the vertical direction SR of the motor vehicle FZ spatially offset from one another. In addition, the five exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 Cross-sections that are of different sizes.

Between every two adjacent exhaust gas outflow openings A01 and AO2 ; AO2 and AO3 ; AO3 and AO4 ; AO4 and AO5 the rear diffuser each has an air guide vane LF on, which are in the form of fish dorsal fin-shaped projections on the rear diffuser HD are shaped and in the longitudinal direction LR of the motor vehicle to the rear of the vehicle FH are directed towards.

The rear diffuser HD further comprises an exhaust flow channel AK , which between the exhaust gas inflow opening E01 and the five exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 is formed and is set up, the exhaust gas from the exhaust gas inflow opening E01 to the exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 to direct.

The exhaust flow channel AK has channel sections KA on, which are designed for sound absorption in the exhaust gas. The channel sections have KA Canal wall WD on, which is coated with a sound-absorbing, elastic material or has a surface structure for soundproofing.

The rear diffuser HD further comprises an air flow channel LK, which the air inflow opening EO2 with the exhaust flow channel AK in the area near the exhaust gas inflow opening E01 fluidically connects.

The rear diffuser HD also includes a controllable / regulatable (gas) compressor VD , which in the exhaust flow passage AK near the exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 is arranged and is set up, the exhaust gas received via the exhaust gas inflow opening EO1 or via the air inflow opening EO2 to compress the air received and thus with a high pressure to the exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 to direct.

At the respective exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 points the rear diffuser HD furthermore a controllable / adjustable aperture each BL1 , BL2 , BL3 , BL4 , BL5 on.

The rear diffuser HD further comprises a control arrangement SA , which on the signal output side with the compressor VD and the bezels BL1 , BL2 , BL3 , BL4 , BL5 is electrically connected and is set up, the compressor VD and the bezels BL1 , BL2 , BL3 , BL4 , BL5 to control or regulate in a manner to be described below.

The car FZ further comprises a vehicle speed sensor GS , which is set up, the driving speed of the motor vehicle FZ capture. The driving speed sensor is on the signal output side GS with a signal input of the control arrangement SA connected in terms of signaling.

• Während der Fahrt des Kraftfahrzeugs FZ bilden sich abhängig von der Fahrgeschwindigkeit des Kraftfahrzeugs FZ hinter dem Kraftfahrzeug FZ Luftverwirbelungen, welche einen Luftunterdruck im Bereich hinter dem Fahrzeugheck FH verursachen. Der Luftunterdruck im Bereich hinter dem Fahrzeugheck FH bremst wiederum das Kraftfahrzeug FZ ab und verschlechtert somit die Aerodynamik des Kraftfahrzeugs FZ. Dabei hängt das Ausmaß der abbremsenden Wirkung der Luftverwirbelungen von der Form und der Größe der Luftverwirbelungen ab.

After removing the rear diffuser HD was described in detail with reference to the figures, its function is described in more detail below:

• While the vehicle is in motion FZ are formed depending on the driving speed of the motor vehicle FZ behind the motor vehicle FZ Air turbulence, which creates negative air pressure in the area behind the rear of the vehicle FH cause. The negative air pressure in the area behind the rear of the vehicle FH in turn brakes the motor vehicle FZ and thus worsens the aerodynamics of the motor vehicle FZ . The extent of the decelerating effect of the air turbulence depends on the shape and size of the air turbulence.

In order to counteract the decelerating effect of air turbulence, the main aim is to prevent the formation of large-scale air turbulence.

For this purpose, the exhaust gas that the rear diffuser HD from the exhaust system AA picks up via the exhaust gas flow channel AK to the compressor VD directed. In the compressor VD the exhaust gas is compressed and the pressure in the exhaust gas is increased. The compressed exhaust gas is then emitted in the form of exhaust gas radiation ST with a high pressure via the exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 in the area behind the rear of the vehicle FH pushed out. The exhaust gas radiation under high pressure ST form laminar flows, which cause turbulent air flows in the area behind the rear of the vehicle FH permanently disturb and thus prevent yourself from being behind the motor vehicle FZ form large-scale air turbulence. Due to the laminar exhaust gas radiation ST form in the area behind the rear of the vehicle FH Small-scale or quasi-laminar air flows LL with comparatively low turbulence. This effectively prevents being behind the motor vehicle FZ Negative air pressure is created.

To strengthen the effect can be added to the exhaust gas from the exhaust system AA still air from the surroundings of the motor vehicle via the air inflow opening EO2 sucked in and in the exhaust flow channel AK be mixed with the exhaust gas to form an exhaust gas-air mixture. The exhaust gas-air mixture is then in the compressor VD compressed and in the form of exhaust-air radiations ST with high pressure in the area behind the rear of the vehicle FH pushed out.

The flow strength of the exhaust gas or exhaust-air radiation emitted ST becomes dependent on the driving speed of the motor vehicle if necessary FZ regulated.

The control arrangement controls this SA depending on the speed sensor connected upstream GS transmitted vehicle speed to the compressor VD so that the agas or exhaust gas / air mixture is compressed to a pressure depending on the current vehicle speed.

As an alternative or in addition to this, the control arrangement controls SA the bezels BL1 , BL2 , BL3 , BL4 , BL5 at the respective exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 so that the flow strength of the respective exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 outflowing exhaust gas or exhaust-gas-air radiation ST be managed. The exhaust gas or exhaust gas-air radiations ST of the respective exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 can be individually regulated independently of each other. With the channel sections KA , which are provided with the sound-absorbing material and / or the surface structure for soundproofing, noise emission from the exhaust gas or exhaust gas-air mixture is reduced.

The air guide vanes LF on the rear diffuser HD also improve the aerodynamics of the motor vehicle FZ through their pull. Due to the alternating arrangement of the air guide vanes LF and the exhaust gas outflow openings AO1 , AO2 , AO3 , AO4 , AO5 air turbulence in the area between the rear diffuser HD and the driving floor as a result of negative air pressure from the gas or exhaust-gas-air radiation ST interrupted. This creates the suction effect of the air guide vanes LF improved again.

With the one-piece rear diffuser described above HD thus at least two functions are implemented in a single vehicle component. These functions are the soundproofing in the exhaust gas and the dynamic improvement of the aerodynamics of the motor vehicle FZ .

Claims (11)

Rear diffuser (HD) for a motor vehicle (FZ), comprising: - at least one exhaust gas inflow opening (EO1) for receiving exhaust gas from an exhaust system (AA) of the motor vehicle (FZ); - At least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5) for discharging the exhaust gas in the form of an exhaust gas flow into the surroundings of the motor vehicle (FZ); - At least one exhaust gas flow channel (AK) between the at least one exhaust gas inflow opening (EO1) and the at least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5); - wherein the at least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5) for changing air turbulence at the vehicle rear (FH) of the motor vehicle (FZ) by the exhaust gas in a longitudinal direction (LR) of the motor vehicle (FZ) to the vehicle rear (FH) is directed towards, characterized in that - the rear diffuser (HD) further comprises at least one controllable / regulatable diaphragm (BL1, BL2, BL3, BL4, BL5) which is attached to the at least one exhaust gas outflow opening (AO1, AO2, AO3, AO4, AO5) is arranged and is set up to regulate the volume flow of the exhaust gas flow. Rear diffuser (HD) after Claim 1 , further comprising a controllable / regulatable compressor (VD) which is arranged in the at least one exhaust gas flow channel (AK) and is set up to regulate the pressure in the exhaust gas flow by compressing the exhaust gas. Rear diffuser (HD) according to one of the preceding claims, further comprising: - At least three exhaust gas outflow openings (AO1, AO2, AO3, AO4, AO5) for discharging the exhaust gas into the surroundings of the motor vehicle (FZ); - the at least three exhaust gas outflow openings (AO1, AO2, AO3, AO4, AO5) for changing the air turbulence at the rear of the vehicle (FH) of the motor vehicle (FZ) through the exhaust gas in the longitudinal direction (LR) of the motor vehicle (FZ) to the rear of the vehicle (FH) are directed towards and are arranged spatially offset from one another in the longitudinal direction (LR), in a transverse direction (QR) and / or in a vertical direction (SR) of the motor vehicle (FZ). Rear diffuser (HD) after Claim 3 , the at least three exhaust gas outflow openings (AO1, AO2, AO3, AO4, AO5) each having a cross-sectional area (QF), the cross-sectional areas (QF) of at least two of the at least three exhaust gas outflow openings (AO1, AO2, AO3, AO4, AO5) being different are great. Rear diffuser (HD) according to one of the preceding claims, wherein the at least one exhaust gas flow channel (AK) has at least one channel section (KA) which is designed for sound attenuation in the exhaust gas. Rear diffuser (HD) after Claim 5 , wherein the at least one channel section (KA) has a wall (WD) with a sound-absorbing material and / or a surface structure for sound-absorbing. Rear diffuser (HD) according to one of the preceding claims, further comprising at least one air guide wing (LF) which is directed towards the rear of the vehicle (FH) in the longitudinal direction (LR) of the motor vehicle (FZ). Rear diffuser (HD) after Claims 3 and 7th , wherein the at least one air guide wing (LF) is arranged in the transverse direction (QR) of the motor vehicle (FZ) between two adjacent ones of the at least three exhaust gas outflow openings (AO1, AO2, AO3, AO4, AO5). Rear diffuser (HD) according to one of the preceding claims, further comprising: - At least one air inflow opening (EO2) for receiving air from the surroundings of the motor vehicle (FZ); - At least one air flow channel (LK) between the at least one air inflow opening (EO2) and the at least one exhaust gas flow channel (AK). Rear diffuser (HD) according to one of the preceding claims, which is also formed in one piece in a molding process. Motor vehicle (FZ), comprising: - An exhaust system (AA) with at least one exhaust gas outflow opening (AO) for discharging the exhaust gas of an internal combustion engine (VM) of the motor vehicle (FZ); - A rear diffuser (HD) according to one of the preceding claims, wherein the rear diffuser (HD) is fluidically connected via the at least one exhaust gas inflow opening (EO1) to the at least one exhaust gas outflow opening (AO) of the exhaust system (AA).

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