CN110778382A

CN110778382A - Gasoline engine tail gas catalytic purification system meeting national emission standards of six countries

Info

Publication number: CN110778382A
Application number: CN201910991775.2A
Authority: CN
Inventors: 王秋艳; 乔锋华; 王伟; 殷超; 李光凤; 姬欢欢; 徐志聪; 戈大朋
Original assignee: ZHEJIANG DAFENG AUTOMOTIVE TECHNOLOGY Co Ltd
Current assignee: ZHEJIANG DAFENG AUTOMOTIVE TECHNOLOGY Co Ltd
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2020-02-11

Abstract

The invention aims to provide a gasoline engine tail gas catalytic purification system which meets the national six-emission standard and is used for solving the problems in the prior art. The gasoline engine tail gas catalytic purification system which accords with the national emission standard of six has a reasonable structure which is convenient for assembly and chassis space arrangement, provides a reasonable tail gas fluid moving path, and can remarkably improve the catalytic performance so as to meet the requirement of the emission standard.

Description

Gasoline engine tail gas catalytic purification system meeting national emission standards of six countries

Technical Field

The invention relates to the field of tail gas purification equipment of vehicle gasoline engines, in particular to a gasoline engine tail gas catalytic purification system meeting the national emission standard.

Background

When automobiles are sold in the market, the admission application of automobile types must be carried out, and an important condition for obtaining approval of the admission application is that the exhaust emission meets the requirements of national emission regulations. Because the engine is high in emission, for a traditional fuel oil type automobile, the automobile exhaust catalytic purifier is an essential part for the automobile exhaust emission to reach the national emission standard requirement. From 7/1 in 2020, all light automobiles sold and registered in China are required to meet the requirements of the emission standard of the sixth stage. Compared with the five-state emission standard, the new standard has the advantage that the allowable emission values of harmful components CO, NOx, THC and NMHC in the exhaust gas are obviously reduced, which means that the performance of the corresponding matched exhaust gas purification system must be improved.

At present, when some manufacturers produce tail gas purification systems capable of meeting the emission standards of the six countries, the method of simply increasing the volume of the catalyst is adopted, and although the requirements can be met in terms of numerical values, the catalyst is large in volume, is inconvenient to arrange and install on a vehicle, and affects the assembly and distribution design.

Disclosure of Invention

The invention aims to provide a gasoline engine tail gas catalytic purification system which meets the national six-emission standard, which is used for solving the problems in the prior art.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

the utility model provides a gasoline engine tail gas catalytic purification system who accords with six emission standard in state, includes that the exhaust subassembly, pre-catalyst, first connecting line, main catalyst and the second connecting line that connect gradually the setting downstream along gasoline engine exhaust direction, inlay respectively in pre-catalyst and the main catalyst and be equipped with catalytic carrier.

Preferably, the pre-catalyst comprises a hollow cylindrical first housing and a cover body, the upstream end of the first housing is connected with the exhaust component in a sealing mode, the downstream end of the first housing is connected with the upstream end of the first connecting pipeline in a sealing mode through a transition end cover, and the cover body is fixedly connected with the outer surface of the first housing at a certain interval.

Preferably, the transition end cap is an eccentric end cap whose upstream end and downstream end do not coincide with each other in axial line.

Preferably, the first connecting line includes a plurality of stepped sections having a gradually decreasing diameter.

Preferably, the stepped section is wrapped with a sleeve.

Preferably, the pre-catalyst and the upstream end and the downstream end of the main catalyst are provided with sensors, respectively.

Preferably, the catalytic carrier is a honeycomb ceramic carrier, a plurality of parallel restricted pore channels are distributed on the catalytic carrier in a honeycomb shape along the exhaust direction of the gasoline engine, the inner walls of the restricted pore channels are coated with catalyst coatings, and the distribution mesh number of the restricted pore channels is more than or equal to 600 meshes.

Preferably, the ratio of the volume of the catalytic carrier in the pre-catalyst to the displacement of the gasoline engine is 0.4-0.8.

Preferably, the ratio of the volume of the catalytic carrier in the main catalyst to the displacement of the gasoline engine is 0.7-1.0.

Preferably, the catalytic carrier is externally wrapped with a gasket, and the outer side of the gasket is connected to the inner walls of the pre-catalyst and the main catalyst in a fitting manner.

The invention has the beneficial effects that:

1. the reasonable and small space arrangement of larger catalytic volume is realized through the pre-catalyst and the main catalyst which are connected in series;

2. the multistage catalytic purification of the gasoline engine exhaust gas with sectional type and controllable flow is realized through the structures of the pre-catalyst and the main catalyst and the middle first connecting pipeline, and the purification effect is further improved.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic cross-sectional view of a precatalyst of the invention;

FIG. 3 is a schematic structural view of a transition end cap of the present invention;

FIG. 4 is a schematic cross-sectional view at a stepped section of the present invention;

the items in the figure are respectively: the device comprises an exhaust assembly 1, a precatalyst 2, a first shell 21, a cover 22, a transition end cover 23, a first connecting pipeline 3, a step section 31, a sleeve 32, a main catalyst 4, a second connecting pipeline 5, a catalytic carrier 6, a gasket 61 and a sensor 7.

Detailed Description

The invention is described in detail below with reference to the attached drawing figures:

as shown in fig. 1, 2, 3 and 4, the system for catalytic purification of tail gas of a gasoline engine meeting the national emission standards comprises an exhaust component 1, a pre-catalyst 2, a first connecting pipeline 3, a main catalyst 4 and a second connecting pipeline 5 which are sequentially connected downstream along the exhaust direction of the gasoline engine, wherein catalytic carriers 6 are respectively embedded in the pre-catalyst 2 and the main catalyst 4. The second connecting line 5 connects downstream to a muffler in the exhaust system downstream. The exhaust assembly 1 is composed of an exhaust manifold on the exhaust side of a vehicle engine, the edge of the upper assembly and the lower assembly is welded to form an integral exhaust manifold which is connected with pipelines with the number of cylinders corresponding to the gasoline engine (4-cylinder machines are pipelines corresponding to 4 exhaust gases, and the like), and the integral exhaust manifold is hermetically connected with the exhaust side of the engine through a flange arranged at the upstream end, so that exhaust gas which is sent out from the exhaust side and does work after combustion enters each component at the downstream. Sealing connection in this application all choose for use the sealed pad that corresponds each flange shape to seal, sealed pad can be for metal or polytetrafluoroethylene etc. can bear the material that exhaust side 800 degrees above high temperature has good sealing performance and high temperature resistance.

In the present embodiment, the precatalyst 2 comprises a first casing 21 in the shape of a hollow cylinder (likewise, the casing of the main catalyst 4 in the present embodiment is also provided with the same kind of material and shape, and the specific dimensional parameters can be changed according to different vehicle chassis spaces) made of metal (preferably stainless steel under the trade marks 409 and 441 for both cost and service performance), and a cover 22 for heat insulation mounted on the outer side. The upstream end of first casing 21 passes through flange sealing connection exhaust subassembly 1, and its downstream end passes through flange structure sealing connection first connecting line 3's upstream end through integrative welded transition end cover 23, and cover body 22 is and has the welding rigid coupling of certain interval with first casing 21 surface, and its coverage is decided according to other pencil arrangement scope in vehicle bottom, promptly: the cover 22 is to insulate at least between the first housing 21 and the wiring harness on the vehicle chassis, thereby insulating its heat radiation from the surrounding wiring harness. Meanwhile, a bracket is welded to the lower portion of the first housing 21 in the present embodiment, and the pre-catalyst 2 is mounted on the chassis of the vehicle body by bolts.

In this embodiment, the transition end cap 23 is an eccentric end cap having an upstream end that is not axially coincident with a downstream end. The eccentric angle and distance can be adjusted according to the installation space of the vehicle chassis, but the upstream end and the downstream end need to be in smooth continuous transition connection. So that on the one hand the ease of installation at the bottom of the vehicle is optimized; on the other hand, the circulation path of the tail gas flow is optimized through smooth continuous transition, and the generation of vibration and noise is reduced; on the other hand, the air flow flowing out of the pre-catalyst 2 can be buffered and decelerated through the eccentric structure, so that the air flow enters the rear main catalyst 4 at a low flow rate to be fully contacted with the catalytic carriers 6 in the main catalyst to realize purification. Therefore, the preliminary purification and the deceleration of the tail gas in the pre-catalyst 2 are realized, and the high-degree purification of the low-speed tail gas in the main catalyst 4 is further realized, so that the requirements of the national emission standard six are met.

In this embodiment, the first connection pipeline 3 includes a plurality of stepped sections 31 (two in this embodiment) with gradually decreasing diameters, and the plurality of stepped sections 31 can further step down the speed of the exhaust gas. The downstream end of the main catalyst is hermetically connected with the main catalyst 2 through a flange, the transition (far away from the upper section) of the upstream end of the main catalyst 2 and the connection part of the upstream end of the main catalyst is preferably realized through a bent pipe, and the similar effect can be realized through a longer straight pipe in a large-sized vehicle.

In this embodiment, the outside parcel of ladder section 31 has sleeve 32, has certain interval between the casing of sleeve 32 and ladder section 31, installs the bellows in this embodiment simultaneously in this interval to play and fall the effect of making an uproar, damping, same, this setting that has the interval also has certain isolated thermal effect, further reduces the influence of tail gas when 2 temperature of precatalyst are higher.

In this embodiment, the pre-catalyst 2 and the upstream end and the downstream end of the main catalyst 4 are respectively provided with a sensor 7, the sensors 7 are installed through sensor holes penetrating through the housings of the pre-catalyst and the main catalyst and used for detecting the state of the tail gas when entering or leaving the purification system, the sensors 7 comprise a pressure sensor, an oxygen sensor and the like and used for comprehensively detecting the state of the tail gas, and meanwhile, the sensors are connected to an ECU of a vehicle to realize controllable detection and recording.

In the embodiment, the catalytic carrier 6 is a honeycomb ceramic carrier, a plurality of parallel restrictive channels are distributed on the catalytic carrier in a honeycomb manner along the exhaust direction of the gasoline engine, the inner walls of the restrictive channels are coated with similar catalyst coatings in a general vehicle exhaust catalytic device, after the exhaust enters the pre-catalyst 2 and the main catalyst 4, the exhaust moves downstream through the restrictive channels, the temperature of the exhaust enables the catalyst coatings to reach the working temperature, catalytic conversion of harmful components in the exhaust is realized, and the distribution mesh number of the restrictive channels is more than or equal to 600 meshes, so that the passing efficiency of the exhaust is high enough and the catalytic contact area is large enough.

In this embodiment, the ratio of the volume of the catalytic carrier 6 in the pre-catalyst 2 to the displacement of the gasoline engine is 0.4 to 0.8, namely: if the displacement is 2.0L of the gasoline engine, the volume of the catalytic carrier 6 in the pre-catalyst 2 is 0.8-1.6L.

In this embodiment, the ratio of the volume of the catalytic carrier 6 in the main catalyst 4 to the displacement of the gasoline engine is 0.7 to 1.0, namely: if the displacement is 2.0L, the volume of the catalytic carrier 6 in the main catalyst 4 is 1.4-2.0L. By the above two volume settings, the purification satisfying high efficiency at a small volume and a high flow rate in the pre-catalyst 2 and the high quality purification at a large volume and a low flow rate in the main catalyst 4 are further enhanced.

In this embodiment, the catalytic carrier 6 is wrapped with a gasket 61 which may be an expansion type, a semi-expansion type or a non-expansion type, and the outer side of the gasket 61 is embedded and connected to the inner walls of the pre-catalyst 2 and the main catalyst 4, so as to further improve the noise reduction and vibration reduction effects.

Further, in this embodiment, according to tail gas clean-up system length and weight, be provided with the lifting hook at 2 low reaches ends of precatalyst, 4 low reaches ends of main catalyst, realize hanging whole tail gas clean-up system on the automobile body, promote tail gas clean-up system's stability, the noise of the interact production between whole mechanical vibration and automobile body/the chassis when avoiding moving.

The above embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention, and various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention fall into the protection scope of the present invention, and the technical contents of the present invention which are claimed are all described in the claims.

Claims

1. The utility model provides a gasoline engine tail gas catalytic purification system who accords with six emission standard in state, its characterized in that includes along gasoline engine exhaust direction downstream exhaust subassembly (1), precatalyst (2), first connecting line (3), main catalyst (4) and the second connecting line (5) that connect gradually the setting, inlay respectively in precatalyst (2) and the main catalyst (4) and be equipped with catalytic carrier (6).

2. The tail gas catalytic purification system of the gasoline engine meeting the national emission standard is characterized in that the pre-catalyst (2) comprises a first hollow cylindrical shell (21) and a cover body (22), the upstream end of the first shell (21) is hermetically connected with the exhaust assembly (1), the downstream end of the first shell is hermetically connected with the upstream end of the first connecting pipeline (3) through a transition end cover (23), and the cover body (22) is fixedly connected with the outer surface of the first shell (21) at a certain interval.

3. The system for catalytic purification of tail gas of a gasoline engine meeting the national emission standards of six as claimed in claim 2, wherein the transition end cover (23) is an eccentric end cover whose upstream end and downstream end do not coincide with each other on the axial line.

4. A system for catalytic purification of the exhaust gases of petrol engines complying with the national emission standards according to claim 1, characterized in that said first connecting line (3) comprises a plurality of stepped sections (31) of decreasing diameter.

5. The tail gas catalytic purification system of the gasoline engine meeting the national emission standard of six is characterized in that the outside of the stepped section (31) is wrapped with a sleeve (32).

6. The system for catalytic purification of tail gas of gasoline engines meeting the national emission standards of six, as set forth in claim 1, characterized in that the pre-catalyst (2) and the upstream end and the downstream end of the main catalyst (4) are respectively provided with sensors (7).

7. The gasoline engine tail gas catalytic purification system according to the national emission standard, according to claim 1, wherein the catalytic carrier (6) is a honeycomb ceramic carrier, a plurality of parallel restricted pore channels are distributed on the carrier in a honeycomb manner along the exhaust direction of the gasoline engine, the inner walls of the restricted pore channels are coated with a catalyst coating, and the distribution mesh number of the restricted pore channels is more than or equal to 600 meshes.

8. The system for catalytic purification of tail gas of a gasoline engine meeting the national emission standard of six countries according to claim 7, characterized in that the ratio of the volume of the catalytic carrier (6) in the pre-catalyst (2) to the displacement of the gasoline engine is 0.4-0.8.

9. The system for catalytic purification of tail gas of a gasoline engine meeting the national emission standard of six countries according to claim 8, characterized in that the ratio of the volume of the catalytic carrier (6) in the main catalyst (4) to the displacement of the gasoline engine is 0.7-1.0.

10. The tail gas catalytic purification system of the gasoline engine meeting the national emission standard of six, as claimed in claim 1, wherein the catalytic carrier (6) is wrapped with a gasket (61), and the outside of the gasket (61) is embedded and connected with the inner walls of the pre-catalyst (2) and the main catalyst (4).