CN216894596U

CN216894596U - Gasoline engine tail gas aftertreatment system and vehicle thereof

Info

Publication number: CN216894596U
Application number: CN202122508042.4U
Authority: CN
Inventors: 赵振兴
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2022-07-05
Anticipated expiration: 2031-10-18

Abstract

The utility model relates to a gasoline engine tail gas aftertreatment system and a vehicle thereof, comprising a three-way catalyst, a particle catcher and a hydrogen injection device for providing hydrogen for the particle catcher; wherein the particulate trap is located downstream of the three-way catalyst; hydrogen gas injection device arrangementThe tail gas outlet section of the three-way catalyst; the pore channel of the catalyst carrier of the three-way catalyst is internally provided with a pore channel for oxidizing at least part of NO in the tail gas into NO₂A noble metal coating of (a); the carrier pore channel of the particle catcher is internally provided with a carrier pore channel for adsorbing NO₂After and H₂Reaction to form NH₃And is capable of reacting with NO to form N₂A second coating layer of (a); the first coating layer is disposed at an upstream portion of the second coating layer. The gasoline engine tail gas after-treatment system provided by the utility model can still treat NO in the tail gas when the automobile engine is in a lean combustion state.

Description

Gasoline engine tail gas aftertreatment system and vehicle thereof

Technical Field

The utility model relates to the technical field of automobiles, in particular to a gasoline engine tail gas aftertreatment system and a vehicle thereof.

Background

At present, an exhaust gas aftertreatment system of a gasoline engine mainly comprises two parts, one part is a three-way catalyst, and the other part is a GPF (particulate trap). The tail gas aftertreatment is mainly completed through a three-way catalyst, three elements catalyzed by the three-way catalyst are three main pollutants of CO, HC and NO in the tail gas, and the three are purified into harmless substances. In the three-way catalyst, the purification process of NO is mainly achieved by reacting with CO or HC to generate nitrogen.

Lean burn technology has been studied by the automotive industry today. The so-called lean combustion technology is popular, namely the air quantity in an engine cylinder is increased (the theoretical air-fuel ratio of a conventional gasoline engine is 14.7:1, and the lean combustion is already in challenge (20-30): 1). However, when the engine is in a lean combustion state, the three-way catalyst cannot purify NO, because when the engine is in the lean combustion state, the emission of CO in the exhaust gas is suddenly reduced to 30% -40%, and CO and HC are preferentially mixed with O₂Reaction, and therefore, a deficiency in CO emissions will directly result in insufficient CO to react with NO, resulting in an increase in NO emissions.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a gasoline engine tail gas aftertreatment system and a vehicle thereof, so that NO in tail gas can be effectively purified and treated when an automobile engine is in a lean combustion state.

In order to achieve the above object, in a first aspect, the present invention provides a gasoline engine exhaust gas after-treatment system, comprising a three-way catalyst and a particulate trap, wherein the particulate trap is located downstream of the three-way catalyst, and the system is characterized by further comprising a device for injecting H₂The hydrogen injection device of (a), the hydrogen injection device being disposed upstream of the particulate trap;

wherein the pore channel of the catalyst carrier of the three-way catalyst is internally provided with a catalyst carrier for oxidizing at least part of NO in the tail gas into NO₂A noble metal coating of (a);

the carrier pore channel of the particle catcher is internally provided with a carrier pore channel for adsorbing NO₂Rear and H₂Reaction to form NH₃And for NH, and₃reaction with NO to form N₂The second coating layer of (1).

Optionally, the three-way catalyst comprises a catalyst shell, the catalyst shell is sequentially divided into a head gas inlet section, a middle section and a tail gas outlet section along the tail gas flowing direction, the catalyst carrier is located in the middle section, and the hydrogen injection device is arranged at the tail gas outlet section of the three-way catalyst; the hydrogen injection device comprises a hydrogen nozzle; and the gas outlet of the hydrogen nozzle extends into the tail gas outlet section of the three-way catalyst, and the hydrogen spraying direction of the hydrogen nozzle is opposite to the tail gas flowing direction.

Optionally, one end of the catalyst carrier, which is close to the tail gas outlet section, is a gas outlet end, and the distance between the gas outlet of the hydrogen nozzle and the gas outlet end is 3-5 times of the pipe diameter of the hydrogen nozzle.

Optionally, a plurality of blades are further arranged in the tail gas outlet section of the three-way catalyst, and the plurality of blades are located at the downstream of the hydrogen injection device so as to inject H injected by the hydrogen injection nozzle₂Mixing with tail gas.

Optionally, the noble metal coating is a Pt coating.

Optionally, the first coating is disposed upstream of the second coating, wherein the first coating is BaCO₃A coating or a BaO coating; the second coating is V₂O₅Coating or WO₃And (4) coating.

Optionally, the system further comprises a control system, a nitrogen oxygen sensor, and an ammonia sensor; wherein the control system is used for receiving the content of the nitrogen oxide detected by the nitrogen-oxygen sensor and controlling the H of the hydrogen injection device based on the received content of the nitrogen oxide₂The amount of injection;

the control system is also used for receiving the content of the ammonia detected by the ammonia sensor and controlling the H of the hydrogen injection device based on the received content of the ammonia₂The amount of injection.

Optionally, the hydrogen injection device further comprises a valve; the valve is used for controlling the hydrogen nozzle to spray H₂。

Optionally, the control system is connected to the valve, and the control system controls whether the valve is opened.

In a second aspect, the present invention provides a vehicle comprising the gasoline engine exhaust after-treatment system of the first aspect.

The utility model relates to a gasoline engine tail gas aftertreatment system and a vehicle thereof, comprising a three-way catalyst, a particle catcher and a hydrogen injection device for providing hydrogen for the particle catcher; wherein the particulate trap is located downstream of the three-way catalyst; the hydrogen injection device is arranged at the tail gas outlet section of the three-way catalyst; a noble metal coating used for oxidizing at least part of nitric oxide in tail gas into nitrogen dioxide is arranged in a pore channel of a catalyst carrier of the three-way catalyst; a first coating used for absorbing nitrogen dioxide and then reacting with hydrogen to generate ammonia gas and a second coating used for enabling the ammonia gas and nitric oxide to react to generate nitrogen gas are arranged in a carrier pore channel of the particle trap. The gasoline engine tail gas after-treatment system provided by the utility model can still treat NO in the tail gas when the automobile engine is in a lean combustion state.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.

FIG. 1 shows a schematic of the configuration of a gasoline engine exhaust after-treatment system of the present invention;

FIG. 2 shows a schematic of another gasoline engine exhaust aftertreatment system of the present invention;

FIG. 3 shows a schematic cross-sectional structure of a catalyst carrier of a three-way catalyst in a gasoline engine exhaust aftertreatment system according to the utility model;

FIG. 4 shows a schematic of the structure of the particulate trap carrier in the gasoline engine exhaust after-treatment system of the present invention;

FIG. 5 shows a cross-sectional structural diagram of a carrier of a particulate trap in a gasoline engine exhaust aftertreatment system of the present invention.

Description of reference numerals: 1. a three-way catalyst; 1-1, a catalyst carrier of a three-way catalyst; 1-2, coating with noble metal; 1-3, a three-way catalyst housing; 2. a particle trap; 2-1, a carrier of the particle catcher; 2-2, a first coating; 2-3, a second coating; 3. a hydrogen gas injection device; 3-1, a hydrogen nozzle; 3-2, a valve; 4. a blade; 5. a control system; 6. a nitrogen-oxygen sensor; 7. an ammonia sensor.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the related art, an exhaust system of a vehicle generally includes a three-way catalyst and a gasoline particulate trap (GPF). The three elements catalyzed by the three-way catalyst are three main pollutants of CO, HC and NO in tail gas, and are reacted into harmless substances through the following reaction formula:

CO+¹/₂O₂→CO₂ (1)

HC+O₂→H₂O+CO₂ (2)

CO+NO→1/2N₂+CO₂ (3)

HC+NO→N₂+H₂O+CO₂ (4)。

however, when the engine is in a lean combustion state, the emission of CO in the exhaust gas is sharply reduced to 30% -40%, and CO and HC are preferentially mixed with O₂Reaction, and therefore, a deficiency in CO emissions will directly result in insufficient CO to react with NO, resulting in an increase in NO emissions. Therefore, the problem that the existing gasoline engine tail gas aftertreatment system cannot purify NOx under the condition of lean combustion can occur.

In view of the above, the present invention provides a gasoline engine exhaust gas after-treatment system, when the automobile engine is in a lean-burn state, the noble metal coating, such as Pt coating (or Pt coating), arranged in the three-way catalyst fully or partially oxidizes NO in the exhaust gas to NO₂Inside the pore of GPF carrier along NO₂A first coating layer disposed at a position upstream in the inflow direction when NO is present₂BaCO in the first coating when flowing through GPF₃(or BaO) to convert NO₂Absorption ofFixation, the principle is as follows:

BaO+2NO₂+¹/₂O₂→Ba(NO₃)₂ (5)

BaCO₃+2NO₂+¹/₂O₂→Ba(NO₃)₂+CO₂ (6)

however, when 50% BaO or BaCO is present on the GPF support₃Reaction to form Ba (NO)₃)₂Then, the reaction of equation (5)/equation (6) becomes slow. Therefore, the present invention provides hydrogen gas, and Ba (NO), to GPF by means of a hydrogen gas injection device₃)₂Reaction is carried out to regenerate BaO or BaCO₃. The utility model arranges a hydrogen injection device in front of GPF, and the hydrogen injection device works by depending on a hydrogen supply system. H₂Has excellent Ba (NO) conversion₃)₂The ability to desorb nitrogen oxides. Specifically, the following formula is given:

Ba(NO₃)₂+CO₂+8H₂→BaCO₃+5H₂O+2NH₃ (7)

Ba(NO₃)₂+CO₂+3H₂→BaCO₃+2NO+3H₂O (8)

further, GPF carrier has pores along NO₂A second coating layer (V) disposed at a position downstream in the inflow direction₂O₅Coating or WO₃Coating) with adsorbed NH₃And NO flowing around the catalyst can be adsorbed and promoted to react as follows:

4NH₃+4NO+O₂→4N₂+6H₂O (9)

further, NH₃And amount of NO, with H₂So the present invention arranges a nitrogen oxygen sensor and ammonia (NH) after GPF₃) A sensor for detecting NH in the GPF tail gas₃And NO content changes. For the control system to control the injection content of hydrogen (when the hydrogen nozzle does not inject H)₂When NO Ba (NO) is present₃)₂The phenomenon of NO desorption; when the hydrogen nozzle injects H₂When it is, Ba (NO)₃)₂The NO is desorbed. If NH is monitored by the ammonia sensor₃Exceeding the predetermined value, H can be controlled₂When the amount of the NO is small, the formula (8) shows that the amount of NO increases and that the NH in GPF is consumed by the NO₃. H can be controlled if the nitrogen-oxygen sensor detects that NO exceeds the standard (exceeds a preset value)₂Multiple injection, the NH at that time can be known from the formula (7)₃Will increase. NH (NH)₃NO will be consumed).

In addition, in order to ensure that the hydrogen entering the GPF can be fully and uniformly mixed with the tail gas, the utility model extends the gas outlet provided with the hydrogen nozzle into the tail gas outlet section of the three-way catalyst, and the H of the hydrogen nozzle₂The injection direction is opposite to the flow direction of the tail gas. And a plurality of blades are arranged in the tail gas outlet section of the three-way catalyst, so that H is₂And the tail gas is fully and uniformly mixed when entering GPF.

Based on the principle, the embodiment of the utility model provides a gasoline engine exhaust aftertreatment system, referring to fig. 1, fig. 1 shows a schematic structural diagram of the gasoline engine exhaust aftertreatment system according to the embodiment of the utility model, as shown in fig. 1, the system may include a three-way catalyst 1 and a particle trap 2, the particle trap 2 is located at the downstream of the three-way catalyst 1, and the system further includes a device for injecting H₂The hydrogen gas injection device 3 of (3), the hydrogen gas injection device 3 being disposed upstream of the particulate trap 2; wherein, the pore canal of the catalyst carrier 1-1 of the three-way catalyst 1 is internally provided with a catalyst carrier for oxidizing at least part of NO in the tail gas into NO₂1-2 of noble metal coating; the pore channel of the carrier 2-1 of the particle catcher 2 is internally provided with a carrier for adsorbing NO₂After and H₂Reaction to form NH₃2-2, and for reacting NH₃Reaction with NO to form N₂2-3.

Wherein, the utility model arranges a noble metal coating layer 1-2 in the pore channel of a catalyst carrier 1-1 of the three-way catalyst 1 to oxidize at least a part of NO in the tail gas flowing through the three-way catalyst 1 into NO₂； NO₂After entering the particle catcher 2, the carrier 2-1 of the particle catcher 2 is in the pore channelThe first coating layer 2-2 is provided to adsorb NO₂Then, H supplied from the hydrogen gas injection device 3₂React to form NH₃. Meanwhile, the second coating 2-3 arranged in the pore channels of the carrier 2-1 of the particle catcher 2 can enable NH₃Reacts with NO in the tail gas to generate N₂And further, when the automobile engine is in a lean combustion state, the gasoline engine tail gas after-treatment system can still treat NO in the tail gas.

In specific implementation, with continued reference to fig. 1, the three-way catalyst 1 may include a catalyst housing 1-3, the catalyst housing is sequentially divided into a head gas inlet section, a middle section, and a tail gas outlet section along a tail gas flow direction, the catalyst carrier 1-1 is located in the middle section, and the hydrogen injection device 3 is disposed in the tail gas outlet section; the hydrogen gas injection device 3 comprises a hydrogen gas nozzle 3-1; the gas outlet of the hydrogen nozzle 3-1 extends into the tail gas outlet section of the three-way catalyst, and the H of the hydrogen nozzle 3-1₂The injection direction is opposite to the flow direction of the tail gas. In the application, the catalyst carrier 1-1 is arranged in the middle section, and the hydrogen injection device 3 is arranged in the tail gas outlet section of the three-way catalyst 1, and the gas outlet of the hydrogen nozzle 3-1 of the hydrogen injection device 3 extends into the tail gas outlet section of the three-way catalyst, so that the H of the hydrogen nozzle 3-1₂The injection direction is opposite to the tail gas flowing direction and is equivalent to H₂Is "flow path lengthened", H₂Is blown away in the tail part of the three-way catalyst to ensure that H₂Time and space for more mixing with tail gas, wait for H₂When forming a certain mixed gas flow with tail gas, the tail gas carries H₂And enters the particle catcher 2.

In a specific implementation, in an embodiment of the present application, an end of the catalyst carrier 1-1 close to the tail gas outlet section is a gas outlet end, and a distance between a gas outlet of the hydrogen nozzle 3-1 and the gas outlet end may be 3 to 5 times a pipe diameter of the hydrogen nozzle 3-1. To ensure the H sprayed from the hydrogen nozzle 3-1₂There is sufficient moving distance and space at the rear of the three-way catalyst.

In particular implementation, referring to fig. 2, fig. 2 shows a schematic structural diagram of a gasoline engine tail gas after-treatment system according to the present invention, as shown in fig. 2, in an implementation of the present inventionIn the embodiment, a plurality of blades 4 are further arranged in the tail gas outlet section, the blades 4 are all positioned at the downstream of the hydrogen injection device 3, and an included angle of 30-60 degrees is formed between each blade 4 and the central axis of the tail gas outlet section so as to enable the H sprayed by the hydrogen nozzle 3-1 to be H₂Mixing with tail gas. This application is through giving vent to anger inside a plurality of blades 4 that set up in three way catalyst converter's afterbody, makes H₂The tail gas is mixed more evenly under the action of the blades 4, and H entering the particle catcher 2 is further enabled to be more uniformly mixed₂Uniformly distributed in each pore channel of the carrier 2-1 to avoid H₂The content in part of the channels of the carrier 2-1 is too high, so that the first coating layer 2-2 in part of the channels can not fully utilize H flowing through₂Cause H₂Problem of partial waste, or H₂The content in part of the channels of the carrier 2-1 is too low, resulting in that the first coating layer 2-2 in part of the channels utilizes H flowing through₂NH generated₃Insufficient, NO escape problems arise. Wherein, the angle between each blade 4 and the central axis of the tail gas outlet section can be freely selected within the range of 30-60 degrees.

In particular implementation, referring to fig. 3, fig. 3 shows a schematic sectional structure of a catalyst carrier of a three-way catalyst in a gasoline engine exhaust aftertreatment system according to the present invention. As shown in FIG. 3, in one embodiment of the present invention, the noble metal coating 1-2 in the pore channels of the catalyst carrier 1-1 of the three-way catalyst 1 may be a Pt coating, an Ag coating or an Rh coating, and the noble metal Pt in the Pt coating can oxidize at least a part of NO in the exhaust gas into NO₂. In a specific application, the Pd coating in the original three-way catalyst 1 can be replaced by a Pt coating.

In particular implementation, referring to fig. 4, fig. 4 illustrates a schematic view of a particulate trap carrier structure in a gasoline engine exhaust aftertreatment system of the present invention. As shown in FIG. 4, in one embodiment of the present invention, a first coating layer 2-2 is disposed upstream of a second coating layer 2-3, wherein the first coating layer 2-2 is BaCO₃A coating or a BaO coating; the second coating 2-3 is V₂O₅Coating or WO₃And (4) coating.

In particular, fig. 4 shows a schematic structural view of the carrier 2-1 of the particle trap 2; referring to fig. 4, the carrier 2-1 has a structure of a first coating layer 2-2 (not shown) and a structure of a second coating layer 2-3 (not shown) provided in the cell channels. The first coating layer 2-2 is arranged upstream in the exhaust gas inflow direction in the cell channels of the carrier 2-1, and the second coating layer 2-3 is arranged downstream in the exhaust gas inflow direction (the first coating layer 2-2 is arranged upstream of the second coating layer 2-3). Wherein, the first coating layer 2-2 and the second coating layer 2-3 can be combined in different ways, which is described in detail below:

the following are exemplified: in the first coating 2-2 is BaCO₃When coating, the second coating 2-3 may be V₂O₅And (4) coating. Referring specifically to fig. 5, fig. 5 shows a schematic cross-sectional structure of the carrier 2-1 of the particulate trap 2, and referring to fig. 5, the carrier 2-1 of the particulate trap 2 has channels similar to the catalyst carrier structure of the three-way catalyst 1; when the exhaust gas enters the particulate trap 2 in the flow direction, BaCO in the first coating layer 2-2 (not shown) inside the catalyst carrier 2-1₃The material first adsorbs NO₂After and H₂Reaction to form NH₃Further, V in a second coating layer 2-3 (not shown in the figure) located downstream of the first coating layer 2-2₂O₅The material can realize NH₃Reaction with NO to form N₂Thereby realizing effective purification treatment of NO in the tail gas.

The following are exemplified: in the first coating 2-2 is BaCO₃When coating, the second coating 2-3 can also be WO₃Coating;

the following are exemplified: when the first coating layer 2-2 is a BaO coating layer, the second coating layer 2-3 may be V₂O₅Coating or WO₃And (4) coating.

In particular implementation, in an embodiment of the present application, the system further includes a control system 5, a nitrogen oxygen sensor 6, and an ammonia sensor 7; wherein the control system 5 is used for receiving the content of the nitrogen oxides detected by the nitrogen-oxygen sensor 6 and controlling the H of the hydrogen injection device 3 based on the received content of the nitrogen oxides₂The amount of injection; the control system 5 is also configured to receive the ammonia content detected by the ammonia sensor 7 and control H of the hydrogen injection device 3 based on the received ammonia content₂The amount of injection.

Continue to useReferring to fig. 2, in an embodiment of the present application, the system further comprises a control system 5; the control system 5 is used for receiving the content of the nitrogen oxides detected by the nitrogen-oxygen sensor 6 and the content of the ammonia detected by the ammonia sensor 7, and if the nitrogen-oxygen sensor 6 detects that NO exceeds a standard (exceeds a preset value), the control system 5 controls H₂Multiple spraying, in which case reaction 7 takes place in the particle trap 2, the NH in the product₃Will increase. Increased NH₃The NO within the particulate trap 2 is consumed (equation 9). If NH is detected by the ammonia sensor 7₃Exceeds the predetermined value, the control system 5 will control H₂Low spray, where equation (8) occurs in the particulate trap 2, NO in the product increases and the increased NO consumes NH from the GPF₃(reaction formula 9).

In particular, in one embodiment of the present application, the hydrogen injection device 3 further includes a valve 3-2 for controlling the hydrogen injection nozzle 3-1 to inject H₂。

In this embodiment, the control system 5 is connected to the valve 3-2, and the control system 5 controls whether the valve 3-2 is opened or not.

Based on the same inventive concept, the embodiment of the utility model also discloses a vehicle which comprises the gasoline engine exhaust aftertreatment system provided by the utility model. For the related explanation of the gasoline engine exhaust gas after-treatment system, reference may be made to the above embodiments, which are not repeated herein.

Because this vehicle is provided with this gasoline engine exhaust aftertreatment system, consequently, this vehicle can realize when the engine is in the thin burning state, and vapour exhaust aftertreatment system still can handle the NO in the tail gas, effectively reduces the pollution of vehicle exhaust to the environment.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

The technical solutions provided by the present invention are described in detail above, and the principles and embodiments of the present invention are described herein by using specific examples, which are only used to help understanding of the present invention, and the content of the present description should not be construed as limiting the present invention. While various modifications of the illustrative embodiments and applications will be apparent to those skilled in the art based upon this disclosure, it is not necessary or necessary to exhaustively enumerate all embodiments, and all obvious variations and modifications can be resorted to, falling within the scope of the disclosure.

Claims

1. The gasoline engine tail gas aftertreatment system comprises a three-way catalyst (1) and a particle trap (2), wherein the particle trap (2) is positioned at the downstream of the three-way catalyst (1), and the gasoline engine tail gas aftertreatment system is characterized by further comprising a catalyst used for spraying H₂The hydrogen injection device (3) of (a), said hydrogen injection device (3) being arranged upstream of the particle trap (2);

wherein a pore channel of a catalyst carrier (1-1) of the three-way catalyst (1) is internally provided with a catalyst carrier for oxidizing at least part of NO in the tail gas into NO₂The noble metal coating (1-2);

the pore channel of the carrier (2-1) of the particle catcher (2) is internally provided with a catalyst for adsorbing NO₂After and H₂Reaction to form NH₃And a first coating (2-2) for NH₃Reaction with NO to form N₂The second coating layer (2-3).

2. The system according to claim 1, wherein the three-way catalyst (1) comprises a catalyst housing (1-3) which is divided into a head gas inlet section, a middle section and a tail gas outlet section in sequence along the flow direction of the exhaust gas, the catalyst carrier (1-1) is located in the middle section, and the hydrogen injection device (3) is arranged at the tail gas outlet section; the hydrogen injection device (3) comprises a hydrogen nozzle (3-1); the gas outlet of the hydrogen nozzle (3-1) extends into the tail gas outlet section of the three-way catalyst, and the H of the hydrogen nozzle (3-1)₂The injection direction is opposite to the exhaust gas flow direction.

3. The system according to claim 2, wherein the end of the catalyst carrier (1-1) close to the tail gas outlet section is a gas outlet end, and the distance between the gas outlet of the hydrogen nozzle (3-1) and the gas outlet end is 3-5 times of the pipe diameter of the hydrogen nozzle (3-1).

4. The system according to claim 2, wherein a plurality of blades (4) are further arranged in the tail gas outlet section, the plurality of blades (4) are located at the downstream of the hydrogen injection device (3), and each blade (4) forms an included angle of 30-60 degrees with a central axis of the tail gas outlet section so as to inject H injected by the hydrogen injection nozzle (3-1)₂Mixing with tail gas.

5. The system according to claim 1, characterized in that the noble metal coating (1-2) is a Pt coating.

6. The system according to claim 1, wherein the first coating (2-2) is arranged upstream of the second coating (2-3), wherein the first coating (2-2) is BaCO₃A coating or a BaO coating; the second coating (2-3) is V₂O₅Coating or WO₃And (4) coating.

7. The system according to claim 1, characterized in that it further comprises a control system (5), a nitrogen oxygen sensor (6) and an ammonia sensor (7); wherein the control system (5) is used for receiving the content of the nitrogen oxide detected by the nitrogen-oxygen sensor (6) and controlling the H of the hydrogen injection device (3) based on the received content of the nitrogen oxide₂The amount of injection;

the control system (5) is also used for receiving the content of ammonia detected by the ammonia sensor (7) and controlling H of the hydrogen injection device (3) based on the received content of ammonia₂The amount of injection.

8. The system according to claim 2, wherein the hydrogen gas injection device (3) further comprises a valve (3-2); the valve (3-2) is used for controllingThe hydrogen gas producing nozzle (3-1) injects H₂。

9. A system according to claim 8, characterized in that the system further comprises a control system (5), the valve (3-2) being connected to the control system (5), the control system (5) controlling whether the valve (3-2) is open or not.

10. A vehicle characterized by comprising a gasoline engine exhaust gas after-treatment system according to any one of claims 1 to 9.