CN111794828A

CN111794828A - Motor vehicle engine exhaust treatment system integrated with silencing structure

Info

Publication number: CN111794828A
Application number: CN201910280628.4A
Authority: CN
Inventors: 袁磊; 何源; 贾克斌; 武鹏; 钟警
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-04-09
Filing date: 2019-04-09
Publication date: 2020-10-20

Abstract

An engine exhaust treatment system integrated with a muffler structure, the engine exhaust treatment system including a plurality of exhaust treatment modules, each exhaust treatment module defining an internal passage therein through which a gas flow can pass, and the plurality of exhaust treatment modules being serially connected in series, the engine exhaust treatment system further including an outlet pipe communicating with the internal passage of a most downstream exhaust treatment module of the plurality of exhaust treatment modules, wherein the most downstream exhaust treatment module has a cylindrical housing, the outlet pipe being disposed through one closed end cap of the cylindrical housing, the muffler structure being at least partially disposed in the cylindrical housing, the muffler structure including: a noise reduction baffle plate formed with a plurality of noise reduction through holes through which a gas flow passes and fixed upstream of the end cap in the cylindrical housing.

Description

Motor vehicle engine exhaust treatment system integrated with silencing structure

Technical Field

The present application relates to an engine exhaust gas treatment system integrated with a sound attenuation structure, and also relates to a motor vehicle equipped with the engine exhaust gas treatment system.

Background

For reasons of environmental protection, engines of motor vehicles, in particular diesel vehicles, are usually equipped with exhaust gas treatment systems. The exhaust gas treatment system has a plurality of exhaust gas treatment modules in order to reduce the emission of environmentally harmful substances in the exhaust gas of the engine.

In general, the engine of a motor vehicle is located in the direction of the front of the vehicle, while the engine exhaust pipe extends under the chassis of the motor vehicle from the engine to the rear of the vehicle, wherein the exhaust pipe must also be arranged around the rear wheel axle of the motor vehicle. As the exhaust emission regulations of motor vehicle engines become more stringent, the number of exhaust treatment modules required to be equipped with the exhaust treatment system of the motor vehicle engine also becomes larger. This results in insufficient space in front of the rear axle to allow the muffler to be installed. A muffler is a device that reduces engine exhaust noise and is generally a necessary component to improve the experience of the driver or passenger of a motor vehicle. Therefore, how to reasonably arrange a silencer in a motor vehicle on the premise of meeting the requirements of increasingly strict exhaust emission regulations becomes an urgent problem to be solved.

Disclosure of Invention

The present application is directed to a sound-deadening structure integrated with an engine exhaust gas treatment system to ensure the riding comfort of the driver or passengers of a motor vehicle on the premise of meeting increasingly stringent exhaust emission regulations.

According to one aspect of the present application, there is provided an engine exhaust treatment system integrated with a sound attenuating structure, the engine exhaust treatment system including a plurality of exhaust treatment modules, each exhaust treatment module defining an internal passage therein through which a gas flow can pass, and the plurality of exhaust treatment modules being connected in series, the engine exhaust treatment system further including an outlet pipe communicating with the internal passage of a most downstream exhaust treatment module of the plurality of exhaust treatment modules, wherein the most downstream exhaust treatment module has a cylindrical housing, the outlet pipe being disposed through one closed end cap of the cylindrical housing, the sound attenuating structure being at least partially disposed in the cylindrical housing, the sound attenuating structure comprising: a noise reduction baffle plate formed with a plurality of noise reduction through holes through which a gas flow passes and fixed upstream of the end cap in the cylindrical housing. Like this, because the amortization structure is integrated in engine exhaust system directly, so can no longer consider external muffler to the motor vehicle chassis structure influence and design the structure of the blast pipe of motor vehicle more in a flexible way to make engine exhaust system can hold the exhaust-gas treatment module of more quantity, satisfy more and more strict exhaust-gas emission regulation requirement.

Optionally, the noise-reduction baffle further includes a connecting through-hole in which one end of the outlet pipe is fixed. Therefore, the extension length of the outlet pipe can be longitudinally shortened, and the flexibility of the structural design of the chassis of the motor vehicle is convenient to increase.

Optionally, the sound-attenuating baffle is disposed substantially perpendicular to a longitudinal axis of the cylindrical shell. In this way it is ensured that the air flow is reflected back and forth in the housing as much as possible before it is discharged from the outlet duct. Optionally, the outlet tube is arranged non-coaxially with the cylindrical housing. Thereby, it is ensured as much as possible that the gas flow is reflected in the housing past the sound-deadening barrier before being discharged from the outlet pipe.

Optionally, the most downstream exhaust treatment module is a diesel particulate filter module comprising a filter cartridge secured within the cylindrical housing upstream of the sound-attenuating baffle. In this way, the filter element can also be used as part of a noise reduction structure for eliminating high frequency noise components generated by the vibration of the gas flow.

Optionally, an additional sound-deadening baffle is fixed in the cylindrical shell upstream of and spaced apart from the sound-deadening baffle, the additional sound-deadening baffle also being formed with a plurality of sound-deadening through-holes. In this way, the sound deadening effect is further enhanced.

Optionally, the outlet pipe is formed with a plurality of openings for the gas flow to pass through in a section between the sound-deadening baffle and the end closure. The silencing effect is further improved because the number of reflections of the gas flow before it is discharged from the exhaust gas treatment system is increased.

Optionally, the end of the outlet tube extending from the closed end cap is flared with a gradually increasing cross-section. Since the flow velocity of the discharged air flow can be reduced, the vibration noise component can be reduced.

According to another aspect of the application, there is also provided a motor vehicle, in particular a diesel vehicle, comprising an engine and an exhaust pipe connected to an exhaust gas outlet end of the engine, wherein the aforementioned engine exhaust gas treatment systems are connected in series within the exhaust pipe.

Adopt above-mentioned technical means of this application, can reduce the degree of difficulty of motor vehicle chassis structural design to ensure that the exhaust treatment system including the exhaust treatment module of more quantity can arrange in the chassis, reduce exhaust noise when satisfying more and more strict exhaust emission regulation requirement.

Drawings

The foregoing and other aspects of the present application will be more fully understood from the following detailed description, taken together with the following drawings. It is noted that the drawings may not be to scale for clarity of illustration and will not detract from the understanding of the present application. In the drawings:

FIG. 1 schematically illustrates an engine exhaust treatment system integrated with a sound attenuating structure, where the engine exhaust treatment system has been installed in an exhaust pipe of a motor vehicle, according to one embodiment of the present application;

FIG. 2 schematically illustrates an enlarged view of a portion of the engine exhaust treatment system of FIG. 1;

FIG. 3 schematically illustrates a portion of a sound attenuating structure in the engine exhaust treatment system shown in FIG. 2;

FIG. 4 schematically illustrates a portion of an engine exhaust treatment system incorporating a sound attenuating structure according to another embodiment of the present application; and is

Fig. 5(a) and 5(b) schematically show noise measurement results when the engine is running, respectively, using the engine exhaust gas treatment system integrated with a sound deadening structure according to the present application.

Detailed Description

In the various figures of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals.

FIG. 1 schematically illustrates an engine exhaust treatment system 100 integrated with a sound attenuating structure, according to one embodiment of the present application. In the context of the present application, the engine exhaust gas treatment system 100 may be an exhaust gas treatment system of an engine of a motor vehicle, in particular a diesel vehicle. The engine exhaust gas treatment system 100 is connected in series in an exhaust pipe 10 of a motor vehicle, particularly a diesel vehicle, and constitutes a part of the exhaust pipe 10. In the context of the present application, the term "connected in series" means that the engine exhaust gas treatment system 100 has an internal passage through which gas can flow in series with the rest of the exhaust pipe, so that the engine exhaust gas must flow through the internal passage in the course of flowing through the entire exhaust pipe.

As further shown in fig. 1, the exhaust pipe 10 includes a pipe segment 20. The pipe section 20 can be connected to the exhaust outlet end of an engine (not shown). The exhaust pipe 10 also includes an engine exhaust gas treatment system 100, which is located downstream of the pipe segment 20. For example, a flange 210 is formed on one end of the pipe segment 20, and a corresponding flange 110 is also provided on the engine exhaust gas treatment system 100, so that the two

flanges

210 and 110 are bolted together to ensure the series connection of the pipe segment 20 with the engine exhaust gas treatment system 100. Longitudinally opposite the flange 110, the engine exhaust treatment system 100 includes an outlet pipe 120 that may be connected to, for example, other pipe sections (not shown) of the exhaust pipe 10.

The engine exhaust treatment system 100 includes a plurality of exhaust treatment modules connected in series. In the context of the present application, the term "exhaust gas treatment" refers to a technique for reducing or eliminating harmful substances in engine exhaust gases as specified in motor vehicle emission legislation. Thus, an exhaust treatment module refers to a module that utilizes the described technology to treat engine exhaust. Taking a diesel engine as an example, these exhaust treatment modules may be a oxidation catalyst (DOC) module, a Selective Catalytic Reduction (SCR) module, a Diesel Particulate Filter (DPF) module, and the like. It will be appreciated that internal channels are formed in each module so that after all modules are connected in series in sequence all internal channels communicate with each other so that gas can flow through the channels to be treated.

The exhaust treatment modules can be connected to each other in series in any suitable order as desired. In the embodiments described herein, the diesel particulate filter module is shown as the most downstream exhaust treatment module; however, in alternative embodiments, the most downstream exhaust treatment module may also be, for example, a selective catalytic reduction module or other (not mentioned) module.

With further reference to FIG. 2, the exhaust treatment module most downstream of the engine exhaust treatment system 100 is shown as a diesel particulate filter module 130. The module 130 includes a housing 1301 and a filter cartridge 1302 mounted within the housing 1301. The housing 1301 is cylindrical in shape, defining an internal passage of the module 130, and a filter cartridge 1302 is positioned in the internal passage such that engine exhaust gas treated via the engine exhaust treatment system 100 may be filtered within the internal passage through the filter cartridge 1302.

The integrated sound attenuating structure of the engine exhaust treatment system 100 is at least partially disposed in the cylindrical housing 1301. For example, a sound attenuating baffle 140 is fixedly disposed within housing 1301 downstream of filter cartridge 1302. For example, sound-deadening baffle 140 is a flat plate and has an outer peripheral shape matching the inner contour of cylindrical casing 1301. Sound attenuating barrier 140 can be secured to the inner wall of cylindrical shell 1301 by interference fit, welding, or other suitable means.

As further shown in fig. 3, a plurality of silencing through holes 141 are formed in silencing baffle 140. In addition, the sound deadening barrier 140 is provided with a connecting through hole 142. The diameter of the connecting through-hole 142 is significantly larger than that of the sound-deadening through-hole 141. Preferably, the connecting through-hole 142 is not located at the geometric center of the noise-reduction baffle 140.

One end portion 121 of outlet pipe 120 can be connected to connecting through hole 142 of sound-deadening baffle 140. For example, the diameter of the end portion 121 of the outlet pipe 120 is slightly smaller than the inner diameter of the connecting through hole 142, so that the end portion 121 of the outlet pipe 120 can be firmly caught in the connecting through hole 142 by means of interference fit. In alternative embodiments, end 121 of outlet tube 120 may also be connected to sound-deadening baffle 140 via welding or other suitable means.

For example, housing 1301 is provided with an end cap 150, which may be secured to housing 1301 by interference fit, welding, or other suitable means, for example. The end cap 150 is formed with only one through-hole corresponding to the shape and position of the coupling through-hole 142 so that the outlet pipe 120 is fixed therethrough.

As shown in fig. 3, in casing 1301, sound-deadening baffle 140 is provided in space 131 downstream of filter element 1302 and upstream of end cap 150, so that engine exhaust gas flowing through filter element 1302 can be reflected back and forth between filter element 1302 and end cap 150, and in the process, repeatedly passes through sound-deadening through-holes 141 in sound-deadening baffle 140. In this way, space 131 forms a Helmholtz (Helmholtz) resonance chamber, while the flow of air is attenuated several times due to the presence of sound-attenuating through-holes 141, thereby correspondingly reducing the velocity of the flow of air and thus the frequency components of the flow-vibrating noise. Thus, the noise component generated by the airflow that has undergone multiple reflections within the helmholtz resonator when it exits outlet tube 120 at end 122 opposite end 121 will be significantly reduced.

According to the solution of the present application, the outlet duct 120 can be arranged around the rear wheel axle of the motor vehicle, since the cross-sectional dimension of the outlet duct 120 is significantly smaller than the cross-sectional dimension of the module 130 or the housing 1301. That is, the engine exhaust treatment system 100 of the present application will no longer be limited to the rear axle location of the motor vehicle, thereby being able to ensure that it is designed to meet increasingly stringent emission regulations. In addition, since the engine exhaust gas treatment system 100 of the present application is integrated with a muffler structure, it is not necessary to equip the exhaust pipe 10 of the motor vehicle with a special muffler, and the chassis structure of the motor vehicle is simplified.

The arrangement and/or diameter size of each silencing through-hole 141 in silencing baffle 140 is preferably designed to be able to provide the necessary gas flow velocity required for exhaust. Furthermore, while in the illustrated embodiment, there is one silencer baffle 140, it should be apparent to those skilled in the art that in alternative embodiments, additional silencer baffles 140 of similar design may be disposed in space 131 without significantly affecting gas flow velocity. For example, in an alternative embodiment, additional sound-deadening baffles provided with a plurality of sound-deadening through-holes 141 may be disposed at intervals upstream and/or downstream of sound-deadening baffle 140 as shown in fig. 2.

In another alternative embodiment, outlet tube 120 may be formed with a plurality of openings in the section between sound-deadening baffle 140 and end cap 150 as shown in fig. 2, so that the gas flow may also oscillate back and forth through these openings, thereby reducing the noise component.

FIG. 4 illustrates an engine exhaust treatment system 200 according to another embodiment of the present application. In contrast to the embodiments described above, and in particular to the embodiment shown in fig. 2, the engine exhaust gas treatment system 200 comprises an outlet pipe 220. This outlet tube 220 differs from the outlet tube 120 shown in fig. 2 in that the former end 220 extending from the closed end cap is flared with a gradually increasing cross-section. As shown, the exposed end 220 of the outlet tube 220 is flared. This design ensures a reduced flow rate per cross-section of the air stream as it passes through the flared end 220, further reducing the noise component that may be generated.

Fig. 5(a) and 5(b) schematically show exhaust noise results measured while the engine is running, for the engine exhaust gas treatment system 100 shown in fig. 2 and the engine exhaust gas treatment system 200 shown in fig. 4, respectively, installed in the same exhaust pipe, wherein the abscissa represents a noise component corresponding to frequency, the left ordinate represents the number of revolutions (rpm) of the engine, and the gray scale level of the right ordinate represents the number of decibels of noise. As can be seen from the measurement results, the noise decibels of the frequency components between 400 Hz and 3500Hz (as shown by the dashed line box in the figure) are obviously reduced during the normal operation of the engine (800-3400 rpm), thereby proving the effectiveness of the engine exhaust gas treatment system in eliminating noise.

In the embodiment described, the most downstream exhaust treatment module, into which the sound-damping arrangement is integrated, is a diesel particle filter module with a filter insert, so that the exhaust gas flow, when passing through the filter openings of the filter insert, also acts to dampen the flow noise because of the reduced flow velocity. Additionally, it should be apparent to those skilled in the art that in an alternative embodiment, the diesel particulate filter module may be replaced by a module without any core material, such as without a filter cartridge 1302 in housing 1301 and merely providing a nozzle for spraying exhaust treatment fluid upstream of sound-damping baffle 140.

Although specific embodiments of the present application have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the application. Various substitutions, alterations, and modifications may be conceived without departing from the spirit and scope of the present application.

Claims

1. An engine exhaust treatment system (100, 200) integrated with a sound deadening structure, the engine exhaust treatment system (100, 200) including a plurality of exhaust treatment modules for exhaust treatment, each exhaust treatment module defining an internal passage therein through which a gas flow can pass, and the plurality of exhaust treatment modules being connected in series, the engine exhaust treatment system (100, 200) further including an outlet pipe (120) communicating with the internal passage of a most downstream exhaust treatment module of the plurality of exhaust treatment modules,

wherein the most downstream exhaust treatment module has a cylindrical housing (1301), the outlet pipe (120) being arranged through one closed end cap (150) of the cylindrical housing (1301),

the sound attenuating structure is at least partially disposed in the cylindrical shell (1301), the sound attenuating structure comprising:

a sound-deadening baffle plate (140) formed with a plurality of sound-deadening through-holes (141) through which a gas flow passes and fixed upstream of the end cap (150) within the cylindrical shell (1301).

2. The engine exhaust gas treatment system (100, 200) with an integrated muffling structure of claim 1, wherein the muffling baffle (140) further comprises a connecting through hole (142), and one end (121) of the outlet pipe (120) is fixed in the connecting through hole (142).

3. The engine exhaust gas treatment system (100, 200) with an integrated silencing structure of claim 1 or 2, wherein the silencing baffle (140) is arranged substantially perpendicular to the longitudinal axis of the cylindrical shell (1301).

4. The engine exhaust gas treatment system (100, 200) with integrated muffler structure according to claim 1 or 2, wherein the most downstream exhaust gas treatment module is a Diesel Particulate Filter (DPF) module comprising a filter cartridge (1302) fixed within the cylindrical housing (131) upstream of the muffler baffle (140).

5. The engine exhaust gas treatment system (100, 200) with an integrated muffling structure of claim 1 or 2, wherein an additional muffling baffle is fixed in the cylindrical shell (1301) upstream of and spaced apart from the muffling baffle (140), the additional muffling baffle also being formed with a plurality of muffling through-holes.

6. The engine exhaust gas treatment system (100, 200) with an integrated sound deadening structure according to claim 1 or 2, wherein the outlet pipe (120) is formed with a plurality of openings through which the gas flow passes in a section between the sound deadening baffle (140) and the end cover (150).

7. The engine exhaust gas treatment system (100, 200) with an integrated sound attenuation structure according to claim 1 or 2, wherein the end of the outlet pipe (120) protruding from the end closure (150) is in a flared shape with a gradually increasing cross section.

8. The engine exhaust gas treatment system (100, 200) with an integrated sound attenuation structure according to claim 1 or 2, characterized in that the outlet pipe (120) is disposed non-coaxially with the cylindrical housing (1301).

9. A motor vehicle comprising an engine and an exhaust pipe connected to an exhaust gas outlet end of the engine, characterized in that an engine exhaust gas treatment system (100, 200) according to any one of claims 1 to 8 is connected in series inside the exhaust pipe.

10. The motor vehicle of claim 9, wherein the motor vehicle is a diesel vehicle.