DE202007007910U1 - Motor vehicle silencer e.g. directly led silencer, has outer pipe comprising broader section, and separating sections provided between three broader sections for developing set of inner and outer sound absorbing areas of different sizes - Google Patents

Abstract

The silencer has an outer pipe (30) comprising a broader section (31) and a tapering section (32). An inner pipe (40) has another broader section (41) and another tapering section. An inner guiding pipe (50) has third broader section (51). A set of separating sections are provided both between the broader sections (31, 41) and between the broader sections (41, 51) for developing a set of inner and outer sound absorbing areas (61a-61e) of different sizes.

Description

The The invention relates to a motor vehicle silencer, in particular a motor vehicle silencer, the a direct or detour-like sound attenuation allows what to increase the engine power leads.

To the combustion of the fuel in the engine, exhaust gas is developed. If the exhaust gas is discharged directly into the air, then arises big noise, as one Air pressure drop from high pressure suddenly to atmospheric pressure occurs. To noise emission To reduce the exhaust gas, the exhaust gas through a motor vehicle silencer for Reduction of the pressure and frequency are passed.

As in 1 shows a conventional bypass type muffler 10 a cylindrical main body 11 on the inside with separator plates 12 in several air chambers 13 are divided. According to the given detour-like design several are in the air chambers 13 provided air ducts 14 connected with each other. Depending on the need, there are several ventilation holes 141 in the respective air lines 14 designed so that through the ventilation holes 141 passing exhaust gas is subjected to an expansion. As shown by arrows in the drawing, the high-pressure exhaust gas emerging from the engine is transmitted through the air ducts 14 guided and inside the air chambers 13 extended. This results in a pressure drop, which causes the sound attenuation.

How out 2 can be seen, has a direct-guided silencer 20 an inner tube 22 on, which is a cylindrical outer tube 21 interspersed. The inner tube 22 is located inside the cylindrical outer tube 21 where several ventilation holes 221 available. The from the inner tube 22 and from the inner wall of the cylindrical outer tube 21 limited sound recording chamber is with sound recording material 23 filled. Therefore, the engine exiting through the ventilation holes 221 of the inner tube 22 passing exhaust gas to be subjected to an expansion that allows the exhaust gas a pressure drop. Noises of the exhaust gas are absorbed by the sound absorbing substance filled in the sound receiving chamber 23 added. This results in a desired sound attenuation.

The above-mentioned motor vehicle silencers have their advantages and disadvantages. With the detour-like silencer 10 occurs a large back pressure due to the complicated exhaust gas flow channels. However, an excellent soundproofing is achieved. With the direct guided silencer 20 a small back pressure is generated due to the simple and smooth exhaust channels, whereby the exhaust gas can be discharged at high speed. However, the noise of the exhaust gas is poorly absorbed, which leads to an increase in noise emission.

Of the Engine is an air pump. His level of performance depends largely on how easily the air in the cylinder or from this enters or exits. The resistance when entering and leaving the cylinder or from this is called pumping loss. That means the least resistance The reduction of the pumping loss causes, thereby delivering an even greater horsepower can be. In order to produce a maximum horsepower, the exhaust gas flow in the Exhaust system to be exposed to minimal resistance. Of the Resistance causes the exit of the exhaust gas from the engine to prevent whereby the subsequent entering into the engine fresh gas-air mixture dilute becomes. This means, that a part of exhaust gas left in the cylinder and thereby with the Gas-air mixture is mixed. This results in the reduction the engine power. If the resistance is increased, then the back pressure arises. In this case, the motor requires an even greater force to prevent the exit of the Allow exhaust gases from the cylinder. This is a source of pumping loss.

All in all have the detour-like silencer and the directly managed silencer according to the prior art own advantages and disadvantages. Besides, they are the two silencers unable to meet the requirements for low noise and maximum horsepower correspond to. Therefore, the conventional silencer require more Improvements.

By The invention provides a motor vehicle silencer, the above mentioned problems avoids the back pressure can decrease with increasing exhaust gas velocity. simultaneously becomes an excellent soundproofing effect achieved.

In addition, will provided by the invention, a motor vehicle silencer, the one detour-like sound damping effect achieved and causes the exhaust flow to a minimum resistance is suspended. This results in optimal engine performance, which the starting horsepower increase by more than 20% can.

The Invention has in particular the features specified in claim 1 on. Advantageous embodiments of the invention are specified in the subclaims.

According to the invention, the flow field of the exhaust gas discharged from the engine is expanded into a plurality of sound receiving chambers before the exhaust gas enters the exhaust pipe. The sound receiving spaces are formed by joining tubes in the axial direction. In addition, each of the tubes has a larger average at the air inlet opening and a smaller average at the air outlet opening. This results in a Venturi tube that achieves a venturi effect. From the Bernoulli equation: Q = ɸ1 × V1 = ɸ2 × V2 the change of the flow velocity is calculated. When passing an equal flow amount (Q) of exhaust gas through the front and rear through-holes, the flow velocity (V2) is increased as the rear-through-hole average ɸ2 decreases. This results in the increase of the flow velocity in the exhaust pipe. This flow velocity causes suction forces around a spray nozzle that move the exhaust gas flow field inside the outer tube. That is, the exhaust gas inside the tubes quickly flows out after the sound deadening expansion, thereby providing a guiding effect that leads to a reduction in the pumping loss of the engine. This ensures increased starting horsepower without increasing noise emissions.

According to the invention, there is provided a vehicle silencer comprising:
an outer tube consisting of a first width portion, a first taper portion and a first narrow end portion, the first width portion having at its front end a closed side in which a through hole is located;
an inner tube consisting of a second width portion, a second cone portion and a second narrow end portion and provided inside the outer tube such that the front portion of the second width portion abuts against the closed side, while the rear portion of the second narrow end portion inside the first narrow end portion passes, wherein a plurality of ventilation holes are in the wall of the second broad section;
an inner guide tube consisting of a third width portion, a third cone portion and a third narrow end portion and provided inside the inner tube such that the front portion of the third wide portion penetrates the through hole of the closed side while the rear portion of the third narrow End portion extends into the interior of the second narrow end portion, and wherein the third wide portion is provided in its located in the interior of the inner tube wall having a plurality of ventilation holes; and
a plurality of separating portions provided both between the first wide portion and the second wide portion and between the second wide portion and the third wide portion so as to form a plurality of different sized inner and outer sound receiving spaces.

in the Following are objects, features and operation of the invention based on the preferred embodiments and the accompanying drawings be explained in more detail. Show it:

1 a schematic representation of a bypass-type silencer according to the prior art;

2 a schematic representation of a direct-guided muffler according to the prior art;

3 a half-section through a motor vehicle silencer according to the invention in a schematic perspective view;

4 an axial section through the motor vehicle silencer according to the invention; and

5 a schematic representation for explaining the Venturi effect of the motor vehicle silencer according to the invention in 4 ,

Referring to the 3 and 4 a motor vehicle silencer according to the invention comprises an outer tube 30 , an inner tube 40 , an inner guide tube 50 and a plurality of separating sections 60 ,

The outer tube 30 consists of a first broad section 31 , a first cone section 32 and a first narrow end portion 33 , The first wide section 31 has at its front end a closed side 34 on, in which there is a through hole 341 located.

The inner tube 40 that from a second broad section 41 , a second cone section 42 and a second narrow end portion 43 is inside the outer tube 30 provided such that the front portion of the second broad section 41 against the closed side 34 abuts while the rear portion of the second narrow end portion 43 inside the first narrow end section 33 arrives. There are also several ventilation holes 411 in the wall of the second broad section 41 ,

The inner guide tube 50 that from a third broad section 51 , a third cone section 52 and a third narrow end section 53 is inside the inner tube 40 so provided that the front portion of the third broad section 51 the through hole 341 the closed side passes through while the rear section of the third narrow end section 53 inside the second narrow end section 43 extends. The third broad section 51 is in its inside the inner tube 40 located wall with a plurality of ventilation holes 511 Mistake.

The separating sections 60 are both between the first broad section 31 and the second wide section 41 as well as between the second broad section 41 and the third broad section 51 designed so that several internal and external sound recording rooms 61a . 61b . 61c . 61d . 61e different size arise, each with sound recording material 62 are filled. The sound recording material 62 consists of sound-absorbing cotton or steel wool or the combination of the two.

The number of inner tubes used 40 is variable as needed. For larger vehicles producing large exhaust gas, one or two layers may be used. For motorcycles that produce small amount of exhaust gas, the inner guide tube may 50 either with the outer tube 30 or with the inner tube 40 interact.

• 1. Das aus dem Motor geleitete Abgas, das durch die Belüftungslöcher 511 des inneren Führungsrohrs 50 hindurchführt, wird zunächst in die Schallaufnahmeräume 61d, 61e ausgedehnt. Weiterhin wird das Abgas von den Belüftungslöchern 411 des Innenrohrs 40 in die Schallaufnahmeräume 61a, 61b, 61c ausgedehnt. Hierdurch ergibt sich die Herabsetzung des Abgasdrucks. Außerdem werden Auspuffgeräusche durch den Schallaufnahmestoff 62 aufgenommen.
• 2. Das aus dem Motor geleitete Abgas, das nicht durch die Belüftungslöcher 511 des inneren Führungsrohrs 50 hindurchführt, wird vom dritten schmalen Endabschnitt 53 des inneren Führungsrohrs 50 durch den zweiten schmalen Endabschnitt 43 des Innenrohrs 40 bis zum ersten schmalen Endabschnitt 33 des Außenrohrs 30 abgelassen. Durch die Vergrößerung des Durchmessers des Auspuffrohrs ergibt sich die Herabsetzung der Ausdehnungswirkung des Abgasdrucks. Darüber hinaus kann das in die Schallaufnahmeräume 61c, 61e ausgedehnte Abgas herausgeleitet werden.

Due to the above-mentioned design, the sound attenuation according to the invention can be divided into two parts.

• 1. The exhaust gas routed from the engine through the ventilation holes 511 of the inner guide tube 50 passes, is first in the sound recording rooms 61d . 61e extended. Furthermore, the exhaust gas from the ventilation holes 411 of the inner tube 40 into the sound recording rooms 61a . 61b . 61c extended. This results in the reduction of the exhaust pressure. In addition, exhaust noise from the Schallaufnahmestoff 62 added.
• 2. The exhaust gas routed from the engine, not through the ventilation holes 511 of the inner guide tube 50 passes, is from the third narrow end portion 53 of the inner guide tube 50 through the second narrow end section 43 of the inner tube 40 to the first narrow end section 33 of the outer tube 30 drained. By increasing the diameter of the exhaust pipe results in the reduction of the expansion effect of the exhaust pressure. In addition, that can be in the sound recording rooms 61c . 61e extended exhaust gas are led out.

In 4 the flow field of the discharged gas is shown with arrows. The sound attenuation occurs both by detours and by a straight line. If the exhaust gas is routed out of the engine at low speed, this will create into the rear sound containment chambers 61c . 61e expanded exhaust gas due to its low flow rate a greater detour effect, which provides for an increased back pressure, which leads to an increase of the torsion. If the exhaust gas is routed out of the engine at high speed, this will create into the rear sound receiving chambers 61c . 61e Extended exhaust due to its high flow velocity and its straight guide a low back pressure. With the dividers 60 become inner and outer sound recording rooms 61a . 61b . 61c . 61d . 61e different size separated from each other. In addition, the exhaust sounds with different pitch using the filled sound absorbing material 62 added. This causes the back pressure to decrease as the exhaust gas velocity increases. In addition, the soundproofing is improved.

In 5 is the venturi effect in each of the 4 shown tubes shown. The air inlet opening [namely the third wide section 51 ] of the inner guide tube 50 According to the embodiment has an average ɸ1 of 50mm, while the air outlet opening [namely, the first narrow end portion 33 ] of the outer tube 30 also has an average ɸ4 of 50 mm. The average should not be limited to this. The motor vehicle silencer according to the invention is characterized in that the second narrow end portion 43 of the inner tube 40 has an average ɸ3 of about 18 mm and extends into the first narrow end section 33 extends. In addition, has the third narrow end portion 43 of the inner guide tube 50 an average ɸ2 of about 9 mm and extends into the second narrow end portion 43 , This results in the multiple effect of the Venturi tube. According to the Bernoulli equation: Q = ɸ1 × V1 = ɸ2 × V2 enters a first spray nozzle 54 around a pressure reduction, the suction forces arise when the diameter of the inner guide tube 50 is reduced from ɸ1 = 50 mm to ɸ2 = 9 mm and the medium at the third narrow end section 53 has an increased flow velocity. This results in a negative pressure. In this way, this occurs inside the outer tube 30 located exhaust gas flow field S1 faster in one inside the second narrow end portion 43 located mixing chamber 44 one. The exhaust gas inside the mixing chamber 44 then flows through a second spray nozzle 45 in the first narrow end section 33 , wherein the exhaust gas flow field S2 in the interior ren the outer tube 30 moved. Therefore, this can be used to silenced the inner guide tube 50 in each of the sound recording rooms 61a . 61b . 61c . 61d . 61e flowing exhaust gas easily by an optimal "conduction" quickly led out, which leads to the reduction of pumping loss of the engine and thereby increase its horsepower.

• 1. Grunddaten des geprüften Kraftwagens: Markenbezeichnung: Mitsubishi FB511W Motortyp: L4 Jahr: Juli 1996 Kennzeichen: L5-3508 Hubraum des Motors: 2,835 L Gewicht: 3490 kg Max. Pferdestärke and Umdrehungen pro Minute: 93/4000 hp/rpm Umgebungstemperatur and Atmosphärendruck: 294.6/100.4 k/kpa
• 2. Prüfungsergebnisse: 2.1 Der herkömmliche Kraftfahrzeugschalldämpfer und der erfindungsgemäße Kraftfahrzeugschalldämpfer beide bestehen die Verschmutzungsprüfung. 2.2 Verhältnis der Pferdestärke: Der herkömmliche Kraftfahrzeugschalldämpfer kann ein Pferdestärkeverhältnis von nur 41% erreichen, während der erfindungsgemäße Kraftfahrzeugschalldämpfer ein Pferdestärkeverhältnis von 61% erreicht. So wird das Pferdestärkeverhältnis um 20% erhöht.

Some data and results from a test conducted by Environmental Protection Bureau of Tao Yuan County, Taiwan on February 6, 2007 are shown as follows.

• 1. Basic data of the tested motor vehicle: Designation: Mitsubishi FB511W Engine type: L4 Year: July 1996 Registration: L5-3508 Engine displacement: 2,835 L Weight: 3490 kg Max. Horsepower and revolutions per minute: 93/4000 hp / rpm Ambient temperature and atmospheric pressure : 294.6 / 100.4 k / kpa
• 2. Test results: 2.1 The conventional motor vehicle silencer and the motor vehicle silencer according to the invention both pass the contamination test. 2.2 Ratio of horsepower: The conventional vehicle silencer can achieve a horsepower ratio of only 41%, while the motor vehicle silencer according to the invention achieves a horsepower ratio of 61%. Thus, the horsepower ratio is increased by 20%.

By the ones mentioned above Descriptions and test results It is found that the motor vehicle silencer of the invention increased horsepower and Engine power ensured, without noise emission as well as to increase environmental impact.

Even though the invention has been described with reference to an example which is currently considered to be the most practical and preferred embodiment, it is understood that the invention is not limited to the disclosed embodiment limited is. On the contrary, various modifications and the like Arrangements are covered, which are within the scope of the appended claims, which agree with the broadest interpretation to all such Modifications and similar To include arrangement.

10

detour like silencer

11

cylindrical main body

12

separating plate

13

air chamber

14

air line

141

vent hole

20

directly guided silencer

21

cylindrical outer tube

22

inner tube

221

vent hole

23

Sound recording material

30

outer tube

31

first wide section

32

first cone section

33

first narrow end section

34

closed page

40

inner tube

41

second wide section

411

vent hole

42

second cone section

43

second narrow end section

44

mixing chamber

45

second spray nozzle

50

inner guide tube

51

third wide section

511

vent hole

52

third cone section

53

third narrow end section

54

first spray nozzle

60

separating section

61a, 61b, 61c, 61d, 61e

Sound recording room

62

Sound recording material

341

Through Hole

Claims (4)

A vehicle silencer, comprising: an outer tube ( 30 ), which consists of a first broad section ( 31 ), a first cone section ( 32 ) and a first narrow end section ( 33 ), the first broad section ( 31 ) at its front end a closed side ( 34 ), in which a through-bore ( 341 ) is located; an inner tube ( 40 ), which consists of a second broad section ( 41 ), a second cone section ( 42 ) and a second narrow end portion ( 43 ) and inside the outer tube ( 30 ) is provided such that the front portion of the second broad section ( 41 ) against the closed side ( 34 ), while the rear portion of the second narrow end portion (FIG. 43 ) into the interior of the first narrow end section ( 33 ), wherein several ventilation holes ( 411 ) in the wall of the second broad section ( 41 ) are located; an inner guide tube ( 50 ) consisting of a third broad section ( 51 ), a third cone section ( 52 ) and a third narrow end section ( 53 ) and inside the inner tube ( 40 ) is provided such that the front portion of the third broad section ( 51 ) the through-hole ( 341 ) passes through the closed side, while the rear portion of the third narrow end portion ( 53 ) into the interior of the second narrow end section ( 43 ), and wherein the third wide section ( 51 ) in its interior of the inner tube ( 40 ) located wall with a plurality of ventilation holes ( 511 ) is provided; and a plurality of separating sections ( 60 ), both between the first broad section ( 31 ) and the second broad section ( 41 ) as well as between the second broad section ( 41 ) and the third broad section ( 51 ) provided so that a plurality of inner and outer sound receiving spaces ( 61a . 61b . 61c . 61d . 61e ) of different sizes arise. Motor vehicle silencer according to claim 1, characterized in that the sound recording rooms ( 61a . 61b . 61c . 61d . 61e ) with sound recording material ( 62 ) are filled. Motor vehicle silencer according to claim 2, characterized in that the sound recording material ( 62 ) is made from sound absorbent cotton or steel wool or from the combination of the two. Motor vehicle silencer according to claim 1, characterized in that the number of the inner tube ( 40 ) is variable as needed.