CN211950643U - Tail gas pipe and engine tail gas after-treatment system - Google Patents
Tail gas pipe and engine tail gas after-treatment system Download PDFInfo
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- CN211950643U CN211950643U CN202020474492.9U CN202020474492U CN211950643U CN 211950643 U CN211950643 U CN 211950643U CN 202020474492 U CN202020474492 U CN 202020474492U CN 211950643 U CN211950643 U CN 211950643U
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- 239000003054 catalyst Substances 0.000 claims description 18
- 230000003584 silencer Effects 0.000 abstract description 6
- 238000004891 communication Methods 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 41
- 230000009467 reduction Effects 0.000 description 9
- 238000003780 insertion Methods 0.000 description 6
- 230000037431 insertion Effects 0.000 description 6
- 238000009434 installation Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The utility model relates to a tail-gas tube and engine exhaust aftertreatment system. The tailpipe includes a first straight portion and a second straight portion in communication with the first straight portion, the second straight portion bent at an angle α relative to the first straight portion, wherein the tailpipe has an overall length
And the length L of the second straight portion2Is composed of
T is the exhaust gas temperature measured at the location where the exhaust pipe is to be located, R is the maximum speed of the engine, Order is the Order of the engine, Order 8 for a four-cylinder engine and 12 for a six-cylinder engine. According to the utility model discloses, can avoid installing the silencer for under the condition that does not sacrifice and fall the performance of making an uproar, can reduce the cost of tailpipe and make the tailpipe easily make and install.
Description
Technical Field
The utility model relates to a tail gas treatment of engine especially relates to tail gas pipe and including the engine exhaust after-treatment system of this kind of tail gas pipe.
Background
With the increasing concern of environmental pollution, the requirements for engine exhaust emission are becoming stricter. For diesel vehicles, engine exhaust after-treatment systems are typically provided. Engine exhaust aftertreatment systems generally include a catalyst system and an exhaust pipe downstream of the catalyst system to reduce the emission of pollutants in the exhaust. In addition, in order to reduce noise generated when exhaust gas is discharged, one or more mufflers are installed in the exhaust pipe. In order to attach the muffler, the length of the tailpipe must be increased, and the lengthened tailpipe must be extended to the rear of the vehicle beyond the rear axle of the vehicle, which makes the tailpipe formed in a complex shape having a plurality of bent portions. The existing tail gas pipe not only causes cost increase because of additionally arranging a silencer and increasing the length, but also is difficult to manufacture and install due to the tail gas pipe with a complex shape.
Thus, there is a need for improvements to existing tailpipes.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to overcome at least one kind of defect that current tail gas pipe exists, provide an improved tail gas pipe. The improved tailpipe enables cost reduction and ease of manufacture and installation without sacrificing noise reduction performance.
The utility model provides a tail gas pipe, a serial communication port, the tail gas pipe includes:
a first straight portion; and
a second straight portion in communication with the first straight portion, the second straight portion bent at an angle α relative to the first straight portion;
wherein the total length L of the tail gas pipetComprises the following steps:
The length L of the second straight portion2Comprises the following steps:
t is the exhaust gas temperature measured at the location where the exhaust pipe is to be located, R is the maximum speed of the engine, Order is the Order of the engine, Order 8 for a four-cylinder engine and 12 for a six-cylinder engine.
The utility model also provides an engine exhaust aftertreatment system, include:
a catalyst system; and
an exhaust pipe mounted downstream of and in communication with the catalyst system;
characterized in that the tailpipe is as described above.
According to the utility model, the total length L of the tail gas pipe is adjustedtIs defined as
And a second length L of the second straight portion2Is defined as
The tail gas pipe noise reduction device has the advantages that the tail gas airflow is enabled to flow flatly and downstream, resonance generated by coupling of the tail gas pipe sound mode and the engine working frequency is avoided, noise is reduced remarkably, a silencer is avoided being installed, the cost of the tail gas pipe can be reduced, and the tail gas pipe is easy to manufacture and install under the condition that the noise reduction performance is not sacrificed.
Drawings
FIG. 1 is a schematic diagram of an engine exhaust aftertreatment system according to the invention;
fig. 2 is a schematic view of a tail gas pipe according to the present invention;
FIGS. 3a-3c schematically show a second section of different sizes of the tailpipe according to the present invention, respectively; and
fig. 4 schematically shows a graph of the relationship between the engine speed and the insertion loss.
It is to be understood that the drawings are designed solely for purposes of illustration and that no limitation on the invention is intended in the form of the details of construction or the arrangement of the components set forth in the drawings. In different drawings, the same or similar components are denoted by the same reference numerals.
Detailed Description
Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, and it is to be understood that the following description is only illustrative of the present invention and is not intended to limit the invention.
As shown in fig. 1, the engine exhaust aftertreatment system 1 of the present invention includes a catalyst system 3. Since the present invention does not relate to the improvement of the catalyst system 3, a detailed description of the catalyst system is omitted. The utility model discloses an engine exhaust aftertreatment system 1 is still including installing 3 low reaches of catalyst converter system and the tail gas pipe 5 with 3 intercommunications of catalyst converter system. For a secure fastening and mounting of the exhaust pipe 5, the exhaust pipe 5 usually extends partially into the catalyst system 3 and is supported on the inner wall of the catalyst system 3 by means of a support plate 7.
As shown in fig. 2, the tailpipe 5 of the present invention includes a first straight portion 7 for connection with the catalyst system 3 and a second straight portion 9 communicating with the first straight portion 7, the second straight portion 9 being bent at an angle α with respect to the first straight portion 7. The second straight portion 9 is bent at an angle alpha relative to the first straight portion 7 in order that, after the tailpipe is in place, the hot exhaust gases discharged from the tailpipe do not discharge horizontally but downwards to the ground in order to avoid damage to vehicle components and spare parts such as spare tires by the hot exhaust gases.
The first straight section 7 has a first length L1, the second straight section 9 has a second length L2, the total length L of the tailpipe 5tIs a first length L1And a second length L2Sum, i.e. Lt＝L1+L2. On the one hand, the total length L of the exhaust pipe 5tThe longer the length, the more beneficial to the leveling and downstream flow of the airflow, the further beneficial to the airflow balance and the reduction of the airflow noise. On the other hand, the total length L of the exhaust pipe 5tThe longer the length is, the lower the resonant frequency of the acoustic mode of the tail gas pipe is, the higher the probability of resonance generated by coupling with the working frequency of the engine is,the greater the noise. According to the utility model, the total length L of the tail gas pipe 5tThe definition is:
where c is the speed of sound, f is the engine ignition frequency, T is the exhaust temperature measured at the location where the exhaust pipe is to be located, R is the maximum speed of rotation of the engine, Order is the Order of the engine, Order is 8 for a four cylinder engine and 12 for a six cylinder engine. In practice, the position at which the exhaust pipe is to be arranged may be selected as the end of the catalyst system, i.e. the temperature of the exhaust gas is measured at the end of the catalyst system at normal pressure.
A second length L of the second straight portion 92The definition is:
by reducing the total length L of the tail gas pipe 5tIs defined as
And a second length L of the second straight portion 92Is defined as
The silencer can prevent the tail gas pipe acoustic mode from being coupled with the working frequency of an engine to generate resonance while enabling the airflow to be smooth and downstream, and obviously reduces noise, thereby avoiding the installation of a silencer.
The second length L of the second straight portion 9 allows for a space for the exhaust pipe 5 and for a better noise reduction2Preferably, the total length L of the tail gas pipe 5tOne third of the total.
According to Laplace Hill's law, the acoustic power L of the jet air flowwExpressed as:
wherein, UJThe velocity of the gas flow at the mouth of the tail gas pipe, rhooIs the atmospheric density, psFor the tail gas density, L is the jet velocity potential length and c is the speed of sound. The formula shows the acoustic power L of the air flowwSpeed U of air flow at pipe orifice of tail gas pipeJIs proportional to the power of eight. By increasing the diameter D of the mouth of the tail gas pipe, the speed U of the air flow at the mouth of the tail gas pipe can be reducedJFurther reducing the airflow acoustic power LwI.e. reduce airflow noise. For a conventional diesel engine, the diameter D of the nozzle of the exhaust pipe is selected to be 60-120 mm. Although in the preferred embodiment the diameters of the first and second straight portions 7, 9 of the tailpipe 5 are selected to be of the same size, it will be appreciated that the diameter of the second straight portion 9 of the tailpipe 5 may be selected to be larger than the diameter of the first straight portion 7 to help further reduce noise.
The greater the degree of bending of the second straight portion 9 with respect to the first straight portion 7, the more unfavourable is the smooth flow of the air flow. The second straight portion 9 is bent too little in relation to the first straight portion 7, which may cause damage to vehicle parts and spare parts, and therefore the angle a at which the second straight portion 9 is bent in relation to the first straight portion 7 is chosen to be 10 ° to 45 °, more preferably 10 ° to 30 °.
As shown in fig. 2, the tail pipe 5 may be formed of a first section 11 and a second section 13 which are separated for convenience of manufacture and installation, opposite ends of the first section 11 and the second section 13 are provided with a first flange 11a and a second flange 13a, respectively, and a fastening member 15 such as a bolt or the like passing through the first flange 11a and the second flange 13a may connect the first section 11 and the second section 13 to form the tail pipe 5. The first section 11 connected to the catalyst system 3 is all the first straight portion 7. The second section 13 may comprise a part of the first straight portion 7 and the second straight portion 9, or may be the second straight portion 9 entirely.
It is right to use the experiment as an example through the four-cylinder engine that rated revolution is 3000rpm, highest rotational speed is 3400rpm the utility model discloses it is verified, and the tail gas temperature of the tail gas pipe department of this engine is about 360 ℃, and the Order value to four-cylinder engine is 8. According to the following formula:
the total length L of the tail gas pipe 5 can be obtainedtNot greater than 550 mm. In the experiment, a two-stage tailpipe 5 was used, in which the first stage 11 comprises a portion of a first straight section 7 having a length of 297mm, and the second stage 13 employs four different specifications as shown in fig. 3:
as shown in fig. 3a, the second section 13 comprises a portion of a first straight portion 7 (having a length of 80mm) and a second straight portion 9 (having a length L2180mm) and the angle alpha of the second straight portion 9 with respect to the first straight portion 7 is 15 deg., and the diameter of both the first straight portion 7 and the second straight portion 9 is 63 mm;
as shown in fig. 3b, the second section 13 substantially comprises only the second straight portion 9 (the length L of which2180mm) and the angle alpha of the second straight portion 9 with respect to the first straight portion 7 is 15 deg., and the second straight portion 9 has the same diameter as the first straight portion 7, all 63 mm; and
as shown in fig. 3c, the second section 13 substantially comprises only the second straight portion 9 (the length L of which2140mm) and the angle alpha of the second straight portion 9 with respect to the first straight portion 7 is 70 deg. and the second straight portion 9 has the same diameter as the first straight portion 7, one size being 57mm and the other size being 63 mm.
Fig. 4 schematically shows a graph of the relationship between the engine speed R and the insertion loss I, in which the abscissa represents the engine speed R and the ordinate represents the insertion loss I. The table below the coordinate system shows the insertion loss I for various engine speeds when different specifications of the tailpipe are used. As is well known, insertion loss I represents the difference in sound pressure level or sound power level measured at a fixed point in space, such as (tailpipe exhaust port) before and after installation of the engine exhaust aftertreatment system of the present invention. The larger the insertion loss I, the better the noise reduction. For the engine, the noise reduction effect of idling and high rotation speed needs to be considered.
As is clear from fig. 4, the experiment has verified that: under the same condition, within the maximum total length, the larger the length of the tail gas pipe is, the better the noise reduction effect is; under the same condition, the larger the diameter of the tail gas pipe is, the better the noise reduction effect is.
Therefore, according to the utility model discloses, through the suitable shape and the parameter of design exhaust pipe, noise when can showing and reducing engine exhaust emission to can get rid of the silencer, make under the condition that does not sacrifice and fall the performance of making an uproar, can reduce exhaust pipe's cost and make exhaust pipe easily make and install.
The invention has been described above with reference to a preferred embodiment only, and it is to be understood that the above description is not a limitation of the invention. The present invention is not limited to the above-mentioned examples, and variations, modifications, additions or substitutions made within the scope of the present invention may be made by those skilled in the art.
Claims (9)
1. An exhaust pipe, characterized in that the exhaust pipe (5) comprises:
a first straight portion (7); and
a second straight portion (9) communicating with the first straight portion (7), the second straight portion (9) being bent at an angle α with respect to the first straight portion (7);
wherein the total length L of the tail gas pipe (5)t：
The length L of the second straight portion (9)2Comprises the following steps:
t is the exhaust gas temperature measured at the location where the exhaust pipe is to be located, R is the maximum speed of the engine, Order is the Order of the engine, Order 8 for a four-cylinder engine and 12 for a six-cylinder engine.
2. The tailpipe according to claim 1, characterized in that the length L of the second straight portion (9)2Approximately the total length L of the tail gas pipe (5)tOne third of the total.
3. The tailpipe according to claim 1, characterized in that the diameter D of the tailpipe (5) is chosen in the range of 60-120 mm.
4. The tailpipe according to claim 1, characterized in that the diameter of the second straight portion (9) is chosen to be larger than the diameter of the first straight portion (7).
5. The tailpipe of claim 1, wherein the angle α is in the range of 10 ° to 30 °.
6. The tailpipe according to claim 1, characterized in that the tailpipe (5) comprises a first section (11) and a second section (13), opposite ends of the first section (11) and the second section (13) being provided with a first flange (11a) and a second flange (13a), respectively, and a fastener (15) passing through the first flange (11a) and the second flange (13a) connects the first section (11) and the second section (13).
7. The tailpipe according to claim 6, characterized in that the first section (11) is the first straight portion (7) and the second section (13) is the second straight portion (9).
8. The tailpipe according to claim 6, characterized in that the first section (11) comprises a part of the first straight portion (7), and the second section (13) comprises the remaining part of the first straight portion (7) and the second straight portion (9).
9. An engine exhaust aftertreatment system comprising:
a catalyst system (3); and
an exhaust pipe (5) mounted downstream of the catalyst system (3) and communicating with the catalyst system (3);
characterized in that the tailpipe (5) is a tailpipe (5) according to any one of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020474492.9U CN211950643U (en) | 2020-04-03 | 2020-04-03 | Tail gas pipe and engine tail gas after-treatment system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020474492.9U CN211950643U (en) | 2020-04-03 | 2020-04-03 | Tail gas pipe and engine tail gas after-treatment system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211950643U true CN211950643U (en) | 2020-11-17 |
Family
ID=73170277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020474492.9U Active CN211950643U (en) | 2020-04-03 | 2020-04-03 | Tail gas pipe and engine tail gas after-treatment system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211950643U (en) |
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2020
- 2020-04-03 CN CN202020474492.9U patent/CN211950643U/en active Active
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