CN114718711B - Device and method for treating vehicle exhaust - Google Patents

Abstract

The embodiment of the invention provides a device and a method for treating automobile exhaust, wherein an electronic control unit controls a sulfur reduction catalyst to perform sulfur reduction adsorption on sulfur dioxide in the exhaust of an engine, and then the exhaust of the engine is introduced into a lean NOx trap to perform nitrogen oxide adsorption treatment, so that the exhaust of the engine entering the lean NOx trap to perform the nitrogen oxide adsorption treatment does not contain sulfur-containing compounds, and the problem that the lean NOx trap is extremely sensitive to sulfur is solved. When the NOx sensor detects that nitrogen oxide exists, the electronic control unit switches the working mode, the over-rich mixed gas in the tail gas of the engine is directly subjected to flow direction regeneration treatment on the lean NOx trap, rather than passing through the sulfur reduction catalyst first, the situation that a large amount of sulfur dioxide adsorbed in the sulfur reduction catalyst is released and then flows into the lean NOx catalyst is avoided, and the problem that in the prior art, desulfurization is difficult to achieve by part of sulfate in the lean NOx trap and the sulfur has incomplete reversible effects on the lean NOx trap is solved.

Description

Device and method for treating vehicle exhaust

technical field

The invention relates to the technical field of tail gas treatment, in particular to a treatment device and method for automobile tail gas.

Background technique

With the implementation of increasingly stringent fuel economy standards for passenger cars, how to further reduce the fuel consumption of cars has become particularly important. In addition to the application of vehicle electrification, how to further improve the thermal efficiency of the engine itself is particularly critical. It has been reported in many literatures that there is still room for improvement in the thermal efficiency of gasoline engines, and lean combustion is one of the important ways to improve the thermal efficiency of gasoline engines. If the exhaust emissions of a lean-burn engine only pass through the three-way catalytic converter, the NOx emissions cannot be effectively converted, and a lean-burn NOx trap needs to be added. Compared with the three-way catalytic converter, the lean-burn NOx trap is more sensitive to sulfur, and its adsorbent also has a strong affinity for sulfur, so that the lean-burn NOx trap is poisoned by sulfur, and the conversion efficiency of NOx is greatly reduced.

High exhaust gas temperature is one of the conditions for the desulfurization process. The Chinese invention patent publication discloses a desulfurization system and method for a lean NOx trap (LNT), including realizing the desulfurization process by increasing the exhaust temperature, which will bring the following The problem is that the way to increase the exhaust temperature includes delaying the ignition angle of the engine and injecting secondary air. The injection of secondary air can increase the exhaust temperature, but in an oxidizing environment with a high oxygen concentration, it is not conducive to the desulfurization reaction. The Chinese Invention Patent Publication discloses an exhaust gas purification method and an exhaust gas purification device with a NOx storage catalyst and a pre-catalyst, and desulfurization is achieved by increasing the exhaust temperature and adding a reducing atmosphere suitable for desorption. But in fact, some sulfides are also difficult to achieve desulfurization process. For example, it is shown in the literature that the sulfate generated by the reaction of sulfur dioxide and engine oil combustion products, once attached to the catalyst in the lean NOx trap, the desulfurization conditions are extremely harsh, and even With partial desulfurization, the conversion efficiency can be restored to a certain extent, but the actual test results show that the effectiveness of the lean NOx trap has been difficult to restore to the original level. That is, sulfur is not fully reversible for lean NOx traps.

To sum up, it is difficult to desulfurize part of the sulfate in the lean NOx trap existing in the prior art, and the influence of sulfur on the lean NOx trap is not completely reversible, resulting in a decrease in the efficiency of the lean NOx trap The problem.

Contents of the invention

In order to solve the above problems, the purpose of the present invention is to provide a treatment device and method for automobile exhaust, which is used to solve the problem that some sulfates in the lean-burn NOx trap existing in the prior art are difficult to desulfurize, and sulfur is harmful to lean-burn NOx traps. The effect of the NOx trap not being fully reversible, leading to the problem of reduced efficiency of the lean burn NOx trap.

In order to solve the above technical problems, the embodiments of the present invention adopt the following technical solutions:

A processing device for automobile exhaust, characterized in that the processing device includes an electronic control unit, a first exhaust pipe, a second exhaust pipe, a third exhaust pipe, a fourth exhaust pipe, a sulfur reducing catalyst, lean NOx trap, NOx sensor, first diverter valve and second diverter valve, the first exhaust pipe, the sulfur reduction catalyst, the second exhaust pipe, the lean NOx trap The NOx sensor is connected to the third exhaust pipe in sequence, the NOx sensor is arranged on the third exhaust pipe, and the end of the first exhaust pipe far away from the sulfur reducing catalyst is connected to the exhaust end of the engine. connect;

The first end of the fourth exhaust pipe is connected to the first exhaust pipe through the first diverter valve, and the second end of the fourth exhaust pipe is connected to the second exhaust pipe through the second diverter valve. The exhaust pipe is connected;

The electronic control unit is electrically connected to the first diverter valve, the second diverter valve, the NOx sensor and the fuel injector on the engine, and is used to control the exhaust gas treatment working mode of the automobile.

Further, the processing device also includes a temperature sensor, a sulfur dioxide sensor, a fifth exhaust pipe, a sixth exhaust pipe, a third diverter valve, a fourth diverter valve and a first valve, and the temperature sensor is arranged on the first valve. On an exhaust pipe, the sulfur dioxide sensor is arranged on the first exhaust pipe;

The first end of the fifth exhaust pipe is connected to the fourth exhaust pipe through the third diverter valve, and the second end of the fifth exhaust pipe is connected to the fourth exhaust pipe through the fourth diverter valve. The third exhaust pipe is connected;

The first end of the sixth exhaust pipe is connected to the first exhaust pipe through the first valve, and the connection between the sixth exhaust pipe and the first exhaust pipe is located in the Between the connection between the fourth exhaust pipe and the first exhaust pipe and the sulfur reduction catalyst, the second end of the sixth exhaust pipe is connected to the third exhaust pipe, and the The connection between the sixth exhaust pipe and the third exhaust pipe is located on the side of the connection between the third exhaust pipe and the fifth exhaust pipe away from the lean NOx trap, and the NOx The sensor is arranged on the side away from the lean NOx trap at the junction of the sixth exhaust pipe and the third exhaust pipe;

The temperature sensor, the sulfur dioxide sensor, the third diverter valve, the fourth diverter valve and the first valve are respectively electrically connected to the electronic control unit.

Further, the electronic control unit is electrically connected to the spark plug on the engine.

Further, the processing device further includes a one-way valve, and the one-way valve is arranged on the sixth exhaust pipe.

Further, the sulfur reduction catalyst includes a catalyst and an adsorbent.

Further, the adsorbent is non-alkali metal.

Further, the processing method includes the following steps:

The embodiment of the present invention also provides a kind of treatment method of automobile exhaust, and described treatment method comprises the following steps:

Processing the exhaust gas of the engine through the first working mode or the second working mode to obtain the first treated exhaust gas;

judging whether there are nitrogen oxides in the first exhaust gas;

When there are nitrogen oxides in the first exhaust gas, the exhaust gas of the engine is processed through the second working model;

When there is no nitrogen oxide in the first exhaust gas, the exhaust gas of the engine is processed through the first working mode;

in:

The first working mode includes working mode 1 in which the exhaust gas of the engine is sequentially subjected to sulfur-reducing adsorption by the sulfur-reducing catalyst and nitrogen oxide adsorption by the lean-burn NOx trap;

The second working mode includes the second working mode of controlling the excess air ratio in the exhaust gas of the engine within a preset range, and regenerating the nitrogen oxides adsorbed in the lean NOx trap.

Further, the processing of the exhaust gas of the engine through the second working model specifically includes:

Obtaining the sulfur content adsorbed in the sulfur reduction catalyst in the first working mode during the sulfur reduction adsorption treatment;

judging whether the sulfur content exceeds a preset desulfurization threshold;

When the sulfur content does not exceed the preset desulfurization threshold, the exhaust gas of the engine is processed through the second working mode.

Further, the second working mode also includes controlling the excess air ratio in the exhaust gas of the engine within a preset range, and controlling the temperature of the exhaust gas of the engine to be higher than the preset temperature threshold, and reverse the lean NOx trap Working mode 3 of regenerating and desulfurizing and regenerating the desulfurization catalytic converter;

Wherein, the exhaust gas of the engine is processed through the first working mode or the second working mode, and obtaining the processed first exhaust gas specifically includes:

Process the exhaust gas of the engine through working mode 1, working mode 2 or working mode 3 to obtain the first treated exhaust gas;

The processing of the exhaust gas of the engine through the second working mode specifically includes:

The exhaust gas of the engine is processed through the working mode 2 or the working mode 3.

Further, after the judging whether the sulfur content exceeds the preset desulfurization threshold, it also includes:

When the sulfur content exceeds the preset desulfurization threshold, the temperature of the exhaust gas of the engine is obtained;

judging whether the temperature of the exhaust gas of the engine exceeds a preset temperature threshold;

When the temperature of the exhaust gas of the engine exceeds the preset temperature threshold, the exhaust gas of the engine is processed through the working mode three.

Further, after the judging whether the temperature of the exhaust gas of the engine exceeds a preset temperature threshold, it also includes:

When the temperature of the exhaust gas of the engine does not exceed the preset temperature threshold, the ignition angle is delayed to the preset angle to ignite and re-judged whether the temperature of the exhaust gas of the engine exceeds the preset temperature threshold.

Further, the value range of the preset desulfurization threshold is 75%-85% of the maximum stored sulfur content of the sulfur reduction catalyst.

Further, the excess air ratio in the exhaust gas of the engine is controlled to be less than 1 in a preset range.

Further, the excess air ratio in the exhaust gas of the engine is within a preset range of 0.9-0.99.

Further, the value range of the preset temperature threshold is 550°C-650°C.

Further, the value range of the preset angle is 1-3°CA.

Compared with the prior art, the beneficial effects of the embodiments of the present invention are:

Embodiments of the present invention provide a processing device and method for automobile exhaust, the processing device includes an electronic control unit, a first exhaust pipe, a second exhaust pipe, a third exhaust pipe, a fourth exhaust pipe, The sulfur reduction catalyst, the lean NOx trap, the NOx sensor, the first diverter valve and the second diverter valve, the sulfur reduction catalyst is controlled by the electronic control unit to reduce the sulfur dioxide in the exhaust gas of the engine, and then the engine’s The exhaust gas is passed into the lean-burn NOx trap for nitrogen oxide adsorption treatment, so that there will be no sulfur compounds in the engine entering the lean-burn NOx trap for nitrogen oxide adsorption treatment, thus solving the problem of the lean-burn NOx trap It is easy to form sulfur poisoning and greatly reduce the conversion efficiency of NOx;

When the NOx sensor detects the existence of nitrogen oxides, the electronic control unit switches the working mode, and the over-rich mixture in the exhaust gas of the engine directly flows to the lean NOx trap for regeneration. Controlled within the preset range, the exhaust gas of the engine is in a rich reducing atmosphere, so that the nitrogen oxides in the lean NOx trap are released, and react with the reducing agent in the exhaust gas of the engine to generate nitrogen that is harmless to the environment . Due to the rich and reducing atmosphere at this time, a small amount of sulfur dioxide in the exhaust gas of the engine will not be adsorbed on the surface of the lean-burn NOx trap to cause sulfur poisoning of the lean-burn NOx trap, but will be directly discharged to the atmosphere to ensure the lean No risk of sulfur poisoning with fueled NOx traps. This ensures that the conversion rate of the lean-burn NOx trap remains in a stable and reversible state, thereby solving the problem that some sulfates in the lean-burn NOx trap in the prior art are difficult to achieve desulfurization, and sulfur has a negative effect on the lean-burn NOx trap. The impact of the collector is not fully reversible, leading to the problem of a decrease in the efficiency of the lean-burn NOx trap.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present application, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is a schematic structural view of working mode 1 of an automobile exhaust treatment device provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of working mode 2 of an automobile exhaust treatment device provided by an embodiment of the present invention;

Fig. 3 is a schematic structural view of working mode 3 of an automobile exhaust treatment device provided by an embodiment of the present invention;

Fig. 4 is a flow chart of a processing method for automobile exhaust provided by an embodiment of the present invention;

Fig. 5 is a logic block diagram of a processing method for automobile exhaust provided by an embodiment of the present invention.

in:

1. Engine; 2. First exhaust pipe; 3. Electronic control unit; 4. Sulfur reduction catalyst; 5. Second exhaust pipe; 6. Lean NOx trap; 7. Third exhaust pipe; 8. The first diverter valve; 9. The front connection; 10. The third diverter valve; 11. The fourth exhaust pipe; 12. The second diverter valve; 13. The fifth exhaust pipe; 14. The fourth diverter valve; 15. The sixth exhaust pipe; 16. The first valve; 17. One-way valve; 18. Temperature sensor; 19. NOx sensor; 20. Fuel injector; 21. Spark plug; 22. Sulfur dioxide sensor.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some of the embodiments of the application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer " and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, Constructed and operative in a particular orientation and therefore should not be construed as limiting to the embodiments of the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

As shown in Figures 1-3, in the description of the embodiments of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, It can be a fixed connection, a replaceable connection, or an integral connection, it can be a mechanical connection, it can also be an electrical connection, it can be a direct connection, it can also be an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application in specific situations.

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

An embodiment of the present invention provides a treatment device for automobile exhaust, the treatment device includes an electronic control unit 3, a first exhaust pipe 2, a second exhaust pipe 5, a third exhaust pipe 7, a fourth exhaust pipe Pipe 11, sulfur reduction catalyst 4, lean NOx trap 6, NOx sensor 19, first diverter valve 8 and second diverter valve 12, the first exhaust pipe 2, the sulfur reduction catalyst 4, The second exhaust pipe 5, the lean NOx trap 6 and the third exhaust pipe 7 are connected in sequence, the NOx sensor 19 is arranged on the third exhaust pipe 7, and the third exhaust pipe 7 An exhaust pipe 2 is connected to the engine 1 at one end away from the sulfur reduction catalytic converter 4;

The first end of the fourth exhaust pipe 11 is connected to the first exhaust pipe 2 through the first diverter valve 8 , and the second end of the fourth exhaust pipe 11 is passed through the second diverter valve 12 Connected with the second exhaust pipe 5;

The electronic control unit 3 is electrically connected to the first diverter valve 8 , the second diverter valve 12 , the NOx sensor 19 and the fuel injector 20 on the engine 1 to control the exhaust gas treatment mode of the vehicle.

Wherein, the electronic control unit 3 is a control unit capable of receiving, processing and controlling information, such as a microcomputer or a single-chip microcomputer.

The electronic control unit 3 controls the following two working modes including working mode one and working mode two;

The workflow of working mode 1 and working mode 2 is as follows:

When starting, the exhaust gas of the engine 1 is processed in the working mode. In the first working mode, the first diverter valve 8 and the second diverter valve 12 respectively close the two ends of the fourth exhaust pipe 11, so that the exhaust gas of the engine 1 will not into the fourth exhaust pipe 11.

The working mode of working mode 1 is shown in Figure 1, the exhaust gas of the engine 1 is discharged from the engine 1, and flows through the first exhaust pipe 2, the sulfur reduction catalytic converter 4, the second exhaust pipe 5, The lean NOx trap 6 and the third exhaust pipe 7; that is, the sulfur dioxide in the exhaust gas of the engine 1 is firstly adsorbed at the sulfur reduction catalyst 4, and then the remaining nitrogen in the exhaust gas of the engine 1 is The oxides are adsorbed at the lean-burn NOx trap 6, so that there is no sulfur-containing compound in the exhaust gas of the engine 1 that enters the lean-burn NOx trap 6 for nitrogen oxide adsorption treatment, thereby solving the problem of the lean-burn NOx trap 6 is very easy to form sulfur poisoning, and solves the problem that the conversion efficiency of NOx in the lean-burn NOx trap 6 is greatly reduced.

The NOx sensor 19 detects whether the exhaust gas flowing through the third exhaust pipe 7 contains nitrogen oxides. When detecting the presence of nitrogen oxides, the NOx sensor 19 sends a signal to the electronic control unit 3, and the electronic control unit 3. Switch the working mode to working mode 2 to process the exhaust gas of the engine 1 .

The working mode of working mode two is shown in Figure 2, the electronic control unit 3 controls the excess air coefficient in the exhaust gas of the engine 1 within a preset range through the fuel injector 20 on the engine 1; the electronic control unit 3 controls The first diverter valve 8 closes the passage of the over-rich mixture of the exhaust gas of the engine 1 to the direction of the sulfur reduction catalyst 4, and opens the passage to the fourth exhaust pipe 11; the electronic control unit 3 controls the second diverter valve 12 to close The exhaust gas flow of the engine 1 flows towards the passage of the sulfur reduction catalyst 4, and opens the passage to the lean NOx trap 6 through part of the second exhaust pipe 5;

The specific working process of the working mode 2: the exhaust gas of the engine 1 is exhausted by the engine 1, and the part flowing through the first exhaust pipe 2 passes through the first diverter valve 8, and the gas flows through the fourth exhaust pipe 11, The part of the second exhaust pipe 5 and the lean burn NOx catcher 6 are then discharged by the third exhaust pipe 7; because the excess air ratio in the exhaust gas of the engine 1 is controlled within the preset range, the exhaust gas of the engine 1 is in a rich state. The nitrogen oxides adsorbed on the lean-burn NOx trap 6 are released under the reducing atmosphere of the combustion engine 1 , and react with the reducing agent in the exhaust gas of the engine 1 to generate nitrogen gas which is harmless to the environment. Due to the rich reducing atmosphere at this time, a small amount of sulfur dioxide in the exhaust gas of the engine 1 will not be adsorbed on the surface of the lean-burn NOx trap 6 to cause sulfur poisoning of the lean-burn NOx trap 6. After the trap 6, it is directly discharged to the atmosphere, thereby ensuring that the lean burn NOx trap 6 has no risk of sulfur poisoning.

Switching between working mode 1 and working mode 2 can ensure that the lean-burn NOx trap 6 has no risk of sulfur poisoning, and can realize that the lean-burn NOx trap 6 performs adsorption treatment on the exhaust gas of the engine 1 and burns NOx leanly. The regeneration cycle of the trap 6 keeps the conversion rate of the lean-burn NOx trap 6 in a stable and reversible state, thereby solving the problem in the prior art that after the lean-burn NOx trap 6 absorbs sulfur, its conversion Technical issues that reduce efficiency.

Wherein, in the second working mode, the second diverter valve 12 closes the exhaust gas flow channel of the engine 1 toward the sulfur reducing catalyst 4 to prevent the exhaust gas from flowing back into the sulfur reducing catalytic converter 4 .

Wherein, the processing device also includes a temperature sensor 18, a sulfur dioxide sensor 22, a fifth exhaust pipe 13, a sixth exhaust pipe 15, a third diverter valve 10, a fourth diverter valve 14 and a first valve 16, the temperature The sensor 18 is arranged on the first exhaust pipe 2, and the sulfur dioxide sensor 22 is arranged on the first exhaust pipe 2;

The first end of the fifth exhaust pipe 13 is connected to the fourth exhaust pipe 11 through the third diverter valve 10, and the second end of the fifth exhaust pipe 13 passes through the fourth diverter valve. The valve 14 is connected with the third exhaust pipe 7;

The first end of the sixth exhaust pipe 15 is connected to the first exhaust pipe 2 through the first valve 16, and the sixth exhaust pipe 15 is connected to the first exhaust pipe 2. The connection is located between the connection between the fourth exhaust pipe 11 and the first exhaust pipe 2 and the sulfur reduction catalyst 4, and the second end of the sixth exhaust pipe 15 is connected to the third exhaust pipe 15. The exhaust pipes 7 are connected, and the connection between the sixth exhaust pipe 15 and the third exhaust pipe 7 is located at the junction of the third exhaust pipe 7 and the fifth exhaust pipe 13 away from all One side of the lean NOx trap 6, the NOx sensor 19 is arranged at the junction of the sixth exhaust pipe 15 and the third exhaust pipe 7, away from the lean NOx trap 6 side;

The temperature sensor 18 , the sulfur dioxide sensor 22 , the third diverter valve 10 , the fourth diverter valve 14 and the first valve 16 are respectively electrically connected to the electronic control unit 3 .

The electronic control unit 3 calculates the sulfur content in the sulfur reduction catalytic converter 4 according to the concentration of sulfur dioxide detected by the sulfur dioxide sensor 22 and enters the sulfur reduction catalytic converter 4, and judges whether the sulfur content exceeds the threshold by comparing the sulfur content with the preset desulfurization threshold. A preset desulfurization threshold, when the preset desulfurization threshold is exceeded, the electronic control unit 3 switches the working mode of the processing device to working mode three;

Working mode three shown in Figure 5, the electronic control unit 3 controls the excess air coefficient in the exhaust gas of the engine 1 within a preset range through the fuel injector 20 on the engine 1; the electronic control unit 3 controls the first Diverter valve 8 closes the channel of the exhaust gas flow of engine 1 to the direction of sulfur reducing catalyst 4, and opens the passage to the fourth exhaust pipe 11; controls the third diverter valve 10 to open the passage to the fifth exhaust pipe 13, and the third The diverter valve 10 closes the passage through the fourth exhaust pipe 11 to the second exhaust pipe 5; the fourth diverter valve 14 opens the third exhaust pipe 7 to communicate with the lean NOx trap 6, and the fourth The diverter valve 14 closes the passage leading to the third exhaust pipe 7 away from the lean NOx trap 6, the second diverter valve 12 closes the passage leading to the fourth exhaust pipe 11, and the second diverter valve 12 opens the second The passage through which the exhaust pipe 5 normally communicates; the first valve 16 opens the passage leading to the sixth exhaust pipe 15 .

The electronic control unit also includes working mode three:

The specific working process of working mode 3 is as follows:

As shown in Figure 3, the exhaust gas of the engine 1 is discharged from the engine 1, through the part of the first exhaust pipe 2, the part of the fourth exhaust pipe 11, the fifth exhaust pipe 13, the lean NOx trap 6, the second The exhaust pipe 5, the sulfur reduction catalytic converter 4 and the sixth exhaust pipe 15 are discharged from the third exhaust pipe 7, wherein the connection between the sixth exhaust pipe 15 and the third exhaust pipe 7 is The side where the third exhaust pipe 7 and the fifth exhaust pipe 13 are connected is away from the lean NOx trap 6, so the exhaust gas can go to the third exhaust pipe 15 through the sixth exhaust pipe 15 The portion of tube 7 is then discharged. The exhaust gas of the engine 1 in the third working mode is a high-temperature exhaust gas that is rich in combustion and suitable for desulfurization. If the rich and high-temperature exhaust gas passes through the sulfur reduction catalyst 4 and the lean NOx trap 6 sequentially, the sulfur dioxide absorbed in the sulfur reduction catalyst 4 will be desulfurized, and a large amount of sulfur dioxide will be released in a short time and flow to Lean burn NOx trap 6, thereby increasing the risk of lean NOx trap 6 sulfur poisoning. Therefore, in working mode three, the exhaust gas from engine 1 passes through the lean-burn NOx trap 6 first, and the high-temperature rich-burn exhaust gas causes the nitrogen oxides adsorbed in the lean-burn NOx trap 6 to be released. The air factor is controlled within the preset range, that is, it reacts with the reducing agent in the high-temperature exhaust gas to generate nitrogen that is harmless to the environment. Further flowing into the sulfur reduction catalyst 4, the rich high-temperature exhaust gas releases the sulfur dioxide adsorbed by the sulfur reduction catalyst 4, thereby realizing the desulfurization regeneration process of the sulfur reduction catalyst 4.

Wherein, the first diverter valve 8 closes the passage of the exhaust gas of the engine 1 to the direction of the sulfur reduction catalytic converter 4 to prevent the exhaust gas from flowing backward to the direction of the engine 1. The first valve 16 can also be a diverter valve, and the sixth exhaust pipe 15 is opened. At the same time as the channel, the channel flowing to the first exhaust pipe 2 to the direction of the engine 1 is also closed to prevent exhaust gas from flowing back to the direction of the engine 1 . In addition, due to the existence of the first diverter valve 8, the effect of preventing the exhaust gas from flowing backward toward the engine 1 has already been realized. Therefore, the first valve 16 can also be selected as an ordinary valve, which is mainly used to prevent exhaust gas from flowing backwards in the working mode 1 and the working mode. In the working mode of mode two, the treated exhaust gas flows out from the sixth exhaust pipe 15 .

Preferably, the processing device further includes a one-way valve 17 , and the one-way valve 17 is arranged on the sixth exhaust pipe 15 . The problem that the exhaust gas discharged from the third exhaust pipe 7 flows back through the sixth exhaust pipe 15 is avoided. All the above connection methods can be welded.

Wherein, the fourth exhaust pipe 11 includes a front connecting portion 9, the first end of the front connecting portion 9 is connected to the first exhaust pipe 2, and the second end of the front connecting portion 9 is connected to the fifth exhaust pipe. 13, the front connecting part 9 is connected to the fourth exhaust pipe 11 by welding, and the setting of the front connecting part 9 facilitates the installation of the first diverter valve 8 and the third diverter valve 10.

Wherein, the second diverter valve 12 closes the passage leading to the fourth exhaust pipe 11 , preventing the tail from flowing back into the passage of the fourth exhaust pipe 11 .

Wherein, the electronic control unit 3 is electrically connected to the spark plug 21 on the engine 1 , so that the ignition angle can be delayed to a preset angle by controlling the spark plug 21 of the engine 1 .

Wherein, the sulfur reduction catalyst 4 includes a catalyst and an adsorbent.

Preferably, the catalyst is preferably platinum catalyst.

Since alkali metal adsorbents are sensitive to sulfur and difficult to achieve desulfurization and regeneration, the adsorbent is preferably a non-alkali metal, wherein the adsorbent can be copper oxide/alumina, which can be effectively regenerated after adsorbing sulfur.

As shown in Fig. 4 and Fig. 5, the present embodiment also provides a kind of processing method of automobile exhaust, and described processing method comprises the following steps:

Processing the exhaust gas of the engine 1 through the first working mode or the second working mode, and obtaining the treated first exhaust gas;

judging whether there are nitrogen oxides in the first exhaust gas;

When there are nitrogen oxides in the first exhaust gas, the exhaust gas of the engine 1 is processed through the second working mode;

When there is no nitrogen oxide in the first exhaust gas, the exhaust gas of the engine 1 is processed through the first working mode;

in:

The first working mode includes the first working mode in which the exhaust gas of the engine is sequentially subjected to sulfur reduction adsorption by the sulfur reduction catalyst 4 and nitrogen oxide adsorption treatment by the lean NOx trap 6;

The working mode 1 is specifically as follows: first, sulfur dioxide in the exhaust gas of the engine 1 is desulfurized and adsorbed, and then the remaining nitrogen oxides in the exhaust gas of the engine 1 are adsorbed, so that the nitrogen oxides in the lean NOx trap 6 are carried out. There is no sulfur-containing compound in the engine 1 treated by adsorption of substances, thereby solving the problem that the lean-burn NOx trap 6 is easily poisoned by sulfur and the conversion efficiency of NOx is greatly reduced.

The second working mode includes working mode 2 in which the excess air ratio in the exhaust gas of the engine 1 is controlled within a preset range, and nitrogen oxides adsorbed in the lean NOx trap 6 are regenerated.

The second working mode is specifically: the over-rich mixture in the exhaust gas of the engine 1 directly flows to the lean NOx trap 6, and the nitrogen oxides adsorbed in the lean NOx trap 6 are regenerated. The excess air ratio in the exhaust gas of engine 1 is controlled within the preset range, and the exhaust gas of engine 1 is in a rich reducing atmosphere, so that the nitrogen oxides adsorbed on the lean NOx trap 6 are released, which is consistent with the exhaust gas of engine 1. The reducing agent in the exhaust gas reacts to produce nitrogen which is harmless to the environment. Due to the rich reducing atmosphere at this time, a small amount of sulfur dioxide in the exhaust gas of the engine 1 will not be adsorbed on the surface of the lean-burn NOx trap 6 to cause sulfur poisoning of the lean-burn NOx trap 6, but will be absorbed by nitrogen oxides. Then it is directly discharged to the atmosphere, thereby ensuring that the lean burn NOx trap 6 has no risk of sulfur poisoning.

The second working mode also includes controlling the excess air ratio in the exhaust gas of the engine 1 within a preset range, and controlling the environment where the exhaust gas temperature of the engine is higher than the preset temperature threshold, and reversely regenerates the lean-burn NOx trap and working mode three for desulfurization and regeneration of the desulfurization catalytic converter;

The third working mode is specifically: since the excess air coefficient in the exhaust of the engine 1 is controlled within the preset range, by delaying the ignition angle to the preset angle to ignite, the temperature of the exhaust gas of the engine 1 is higher than the preset temperature threshold suitable for desulfurization , that is, the exhaust gas of the engine 1 in the third working mode is a high-temperature exhaust gas that is rich in fuel and suitable for desulfurization.

Wherein, the excess air ratio in the exhaust gas of the engine 1 is controlled within a preset range of less than 1, and the excess air ratio in the exhaust gas of the engine 1 is controlled within a preset range, which is further preferably 0.9-0.99. In order to realize that the exhaust gas of the engine 1 is in a rich reducing atmosphere, the nitrogen oxides adsorbed by the lean NOx trap 6 are released, and react with the reducing agent in the exhaust gas of the engine 1 to generate nitrogen gas which is harmless to the environment.

The second working mode includes working mode 2 and working mode 3, and one of the modes is selected according to actual conditions during work.

The device for sulfur reduction and sulfur regeneration in the first working mode and the second working mode is a sulfur reducing catalyst.

Wherein, the exhaust gas of the engine 1 is processed through the first working mode or the second working mode, and obtaining the processed first exhaust gas specifically includes:

Processing the exhaust gas of the engine 1 through working mode 1, working mode 2 or working mode 3 to obtain the first treated exhaust gas;

Described and handle the exhaust gas of engine 1 by the second working model specifically include:

And the exhaust gas of the engine 1 is processed through the working mode 2 or the working mode 3.

It is judged by the NOx sensor 19 whether there are nitrogen oxides in the first exhaust gas obtained after the exhaust gas of the engine 1 is processed by using the working mode 1, the working mode 2 or the working mode 3;

When there is no nitrogen oxide in the first exhaust gas, it means that NOx can be adsorbed, and the exhaust gas of the engine 1 can be treated in the working mode.

When there are nitrogen oxides in the first exhaust gas, that is, the adsorption of NOx is not complete, and the lean NOx trap 6 cannot perform NOx adsorption according to actual needs, therefore, it is necessary to switch to working mode 2 or working mode 3 working. Working mode 2 controls the excess air ratio in the exhaust gas of engine 1 within the preset range, that is, the exhaust gas of engine 1 is in a rich reducing atmosphere, so that the nitrogen oxides adsorbed by the lean NOx trap are released, and The reducing agent in the exhaust gas of the engine 1 reacts to generate environmentally harmless nitrogen, that is, the adsorbed nitrate on the lean NOx trap 6 is decomposed to release NOx, and the NOx is further reduced to N ₂ by the reducing agent, so that The lean NOx trap 6 is regenerated. In working mode 2, when the first exhaust gas after processing the exhaust gas of the engine 1 is processed, and the first exhaust gas is re-detected and judged, when there is no nitrogen oxide in the first exhaust gas, that is, the lean NOx trap 6 is regenerated After completion, switch back to the working mode at this time to process the exhaust gas of the engine 1 .

Wherein, the processing of the exhaust gas of the engine 1 by the second working model specifically includes:

Obtaining the sulfur content adsorbed in the sulfur reduction catalyst in the first working mode during the sulfur reduction adsorption treatment;

judging whether the sulfur content exceeds a preset desulfurization threshold;

The setting of the preset desulfurization threshold is related to the sulfur reduction catalyst 4 , and the value range of the preset desulfurization threshold is generally set to be 75%-85% of the maximum stored sulfur content of the sulfur reduction catalyst 4 . The purpose of judging whether the sulfur content in the sulfur reducing catalytic converter 4 exceeds the desulfurization threshold is to judge the working condition of the sulfur reducing catalytic converter 4 .

When the sulfur content does not exceed the preset desulfurization threshold, the exhaust gas of the engine 1 is processed through the second working mode.

When the sulfur content does not exceed the preset desulfurization threshold, it can be known that the sulfur reduction catalyst 4 is not in a saturated state, and can continue to perform sulfur reduction and adsorption on the exhaust gas of the engine 1 . Therefore, only the exhaust gas from the engine 1 in working mode 2 needs to be processed to regenerate the lean NOx trap 6 so that the lean NOx trap 6 can be reused later.

After the judging whether the sulfur content exceeds the preset desulfurization threshold, it also includes:

When the sulfur content exceeds the preset desulfurization threshold, the temperature of the exhaust gas of the engine 1 is obtained;

When the sulfur content exceeds the preset desulfurization threshold, it can be known that the sulfur reducing catalytic converter 4 is about to enter a saturated state, and the sulfur reducing catalytic converter 4 needs to be regenerated so that the sulfur reducing catalytic converter 4 can be reused later.

Judging whether the temperature of the exhaust gas of the engine 1 exceeds a preset temperature threshold;

By acquiring the temperature of the exhaust gas of the engine 1, it is judged whether the condition for desulfurization and regeneration of the sulfur reduction catalytic converter 4 is met, that is, whether the exhaust gas of the engine 1 is a high-temperature exhaust gas that is rich in fuel and suitable for desulfurization. The value range of the preset temperature threshold is 550-650 degrees.

When the temperature of the exhaust gas of the engine 1 exceeds the preset temperature threshold, the exhaust gas of the engine 1 is processed through the working mode three.

When the temperature of the exhaust gas of the engine 1 exceeds the preset temperature threshold, that is, the exhaust gas of the engine 1 is a high-temperature exhaust gas that is rich in fuel and suitable for desulfurization, and satisfies the conditions for the desulfurization and regeneration of the sulfur reduction catalytic converter 4, so switch to working mode 3, While regenerating the lean-burn NOx trap 6, desulfurization and regenerating the desulfurization catalytic converter 4 is performed, so as to continue to be used when switching to working mode 1 later.

After said judging whether the temperature of the exhaust gas of said engine 1 exceeds the preset temperature threshold, it also includes:

When the temperature of the exhaust gas of the engine 1 does not exceed the preset temperature threshold, the ignition angle is delayed to the preset angle for ignition and re-judged whether the temperature of the exhaust gas of the engine 1 exceeds the preset temperature threshold.

When the temperature of the exhaust gas of the engine 1 does not exceed the preset temperature threshold, the exhaust gas of the engine 1 is not a high-temperature exhaust gas that is rich in combustion and suitable for desulfurization, that is, it does not meet the conditions for desulfurization and regeneration of the desulfurization catalytic converter 4. Therefore, by repeating The temperature of the exhaust gas of the engine 1 is increased by delaying the ignition angle to the preset angle of ignition until the temperature of the exhaust gas of the engine 1 exceeds the preset temperature threshold, thereby realizing the high-temperature exhaust gas of the exhaust gas of the engine 1 that is rich in combustion and suitable for desulfurization, That is, satisfy the conditions for desulfurization and regeneration of the sulfur reduction catalyst 4, and then switch to the third working mode, and perform desulfurization and regeneration on the sulfur reduction catalytic converter 4 while regenerating the lean NOx trap 6, so as to switch to the first working mode later. continue to use it.

Wherein, by controlling the spark plug 21 of the engine 1, the ignition angle is delayed to a preset angle for ignition. The value range of the preset angle is 1-3°CA.

In addition, in the exhaust gas treatment of the engine 1, the working mode 1 is the main operating mode, accounting for about 75% of the running time of the entire sulfur reduction treatment;

Working mode 2 is the secondary operating mode, accounting for about 24% of the running time of the entire sulfur reduction treatment;

Since there are few sulfur components in the exhaust gas of the engine 1 , it is difficult to make the sulfur content adsorbed in the sulfur reduction catalyst 4 exceed the preset desulfurization threshold in a short period of time during normal use. Therefore, the third working mode only accounts for about 1% of the running time of the entire sulfur reduction treatment.

Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-OnlyMemory), random access memory (RAM, Random Access Memory), magnetic disk or optical disc and other media that can store program codes.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (15)

1. A treatment device for automobile exhaust, characterized in that the treatment device comprises an electronic control unit, a first exhaust pipe, a second exhaust pipe, a third exhaust pipe, a fourth exhaust pipe, a sulfur reduction catalyst device, lean NOx trap, NOx sensor, first diverter valve and second diverter valve, the first exhaust pipe, the sulfur reduction catalyst, the second exhaust pipe, the lean NOx The trap is connected to the third exhaust pipe in sequence, the NOx sensor is arranged on the third exhaust pipe, and the end of the first exhaust pipe far away from the sulfur reducing catalyst is connected to the exhaust gas of the engine. terminal connection; The first end of the fourth exhaust pipe is connected to the first exhaust pipe through the first diverter valve, and the second end of the fourth exhaust pipe is connected to the second exhaust pipe through the second diverter valve. The exhaust pipe is connected; The electronic control unit is electrically connected to the first diverter valve, the second diverter valve, the NOx sensor and the fuel injector on the engine, and is used to control the exhaust gas treatment working mode of the automobile; The processing device also includes a temperature sensor, a sulfur dioxide sensor, a fifth exhaust pipe, a sixth exhaust pipe, a third diverter valve, a fourth diverter valve, and a first valve, and the temperature sensor is arranged on the first exhaust pipe. On the pipe, the sulfur dioxide sensor is arranged on the first exhaust pipe; The first end of the fifth exhaust pipe is connected to the fourth exhaust pipe through the third diverter valve, and the second end of the fifth exhaust pipe is connected to the fourth exhaust pipe through the fourth diverter valve. The third exhaust pipe is connected; The first end of the sixth exhaust pipe is connected to the first exhaust pipe through the first valve, and the connection between the sixth exhaust pipe and the first exhaust pipe is located in the Between the connection between the fourth exhaust pipe and the first exhaust pipe and the sulfur reduction catalyst, the second end of the sixth exhaust pipe is connected to the third exhaust pipe, and the The connection between the sixth exhaust pipe and the third exhaust pipe is located on the side of the connection between the third exhaust pipe and the fifth exhaust pipe away from the lean NOx trap, and the NOx The sensor is arranged on the side away from the lean NOx trap at the junction of the sixth exhaust pipe and the third exhaust pipe; The temperature sensor, the sulfur dioxide sensor, the third diverter valve, the fourth diverter valve and the first valve are respectively electrically connected to the electronic control unit. 2. The vehicle exhaust gas treatment device according to claim 1, wherein the electronic control unit is electrically connected to the spark plug on the engine. 3. The vehicle exhaust treatment device according to claim 1, characterized in that the treatment device further comprises a one-way valve, and the one-way valve is arranged on the sixth exhaust pipe. 4. The vehicle exhaust gas treatment device according to claim 1, characterized in that, the sulfur reduction catalyst comprises a catalyst and an adsorbent. 5. The vehicle exhaust gas treatment device according to claim 4, characterized in that the adsorbent is a non-alkali metal. 6. A treatment method for automobile exhaust, characterized in that said treatment method comprises the steps of: Processing the exhaust gas of the engine through the first working mode or the second working mode to obtain the first treated exhaust gas; judging whether there are nitrogen oxides in the first exhaust gas; When there are nitrogen oxides in the first exhaust gas, the exhaust gas of the engine is processed through the second working model; When there is no nitrogen oxide in the first exhaust gas, the exhaust gas of the engine is processed through the first working mode; in: The first working mode includes working mode 1 in which the exhaust gas of the engine is sequentially subjected to sulfur-reducing adsorption by the sulfur-reducing catalyst and nitrogen oxide adsorption by the lean-burn NOx trap; The second working mode includes the second working mode of controlling the excess air ratio in the exhaust gas of the engine within a preset range, and regenerating the nitrogen oxides adsorbed in the lean NOx trap. 7. the processing method of automobile exhaust according to claim 6, is characterized in that, described processing the exhaust of engine by the second working mold specifically comprises: Obtaining the sulfur content adsorbed in the sulfur reduction catalyst in the first working mode during the sulfur reduction adsorption treatment; judging whether the sulfur content exceeds a preset desulfurization threshold; When the sulfur content does not exceed the preset desulfurization threshold, the exhaust gas of the engine is processed through the second working mode. 8. The processing method of automobile exhaust according to claim 7, characterized in that, the second mode of operation also includes controlling the excess air coefficient in the exhaust of the engine within a preset range, controlling the temperature of the exhaust of the engine to be higher than the preset Working mode 3 of regenerating the lean NOx trap and desulfurizing and regenerating the sulfur reduction catalyst in an environment where the temperature threshold is set; Wherein, the exhaust gas of the engine is processed through the first working mode or the second working mode, and obtaining the processed first exhaust gas specifically includes: Process the exhaust gas of the engine through working mode 1, working mode 2 or working mode 3 to obtain the first treated exhaust gas; The processing of the exhaust gas of the engine through the second working model specifically includes: The exhaust gas of the engine is processed through the working mode 2 or the working mode 3. 9. according to the processing method of automobile exhaust described in claim 7, it is characterized in that, after described judging whether described sulfur content exceeds preset desulfurization threshold, also comprises: When the sulfur content exceeds the preset desulfurization threshold, the temperature of the exhaust gas of the engine is obtained; judging whether the temperature of the exhaust gas of the engine exceeds a preset temperature threshold; When the temperature of the exhaust gas of the engine exceeds the preset temperature threshold, the exhaust gas of the engine is processed through the working mode three. 10. The processing method of automobile exhaust according to claim 9, characterized in that, after the said judging whether the temperature of the exhaust of said engine exceeds a preset temperature threshold, it also includes: When the temperature of the exhaust gas of the engine does not exceed the preset temperature threshold, the ignition angle is delayed to the preset angle for ignition, and it is re-judged whether the temperature of the exhaust gas of the engine exceeds the preset temperature threshold. 11. The method for treating automobile exhaust according to claim 7, characterized in that, the value range of the preset desulfurization threshold is 75%-85% of the maximum stored sulfur content of the sulfur reduction catalyst. 12. The method for treating automobile exhaust according to claim 6, characterized in that the excess air ratio in the exhaust of the engine is controlled to be less than 1 in a preset range. 13. The method for treating automobile exhaust according to claim 12, characterized in that the excess air ratio in the exhaust of the engine is controlled within a preset range of 0.9-0.99. 14. The method for treating automobile exhaust according to claim 10, wherein the value range of the preset temperature threshold is 550-650 degrees. 15. The method for treating automobile exhaust according to claim 10, characterized in that, the value range of the preset angle is 1-3°CA.

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