CN115126581A

CN115126581A - Tail gas post-treatment device and tail gas emission control method

Info

Publication number: CN115126581A
Application number: CN202210743051.8A
Authority: CN
Inventors: 郭英俊; 钱丁超; 马赫阳; 王艳龙; 周天鹏; 韩云峰; 施伟龙; 耿真; 宋庆文
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2022-06-27
Filing date: 2022-06-27
Publication date: 2022-09-30
Anticipated expiration: 2042-06-27
Also published as: CN115126581B

Abstract

The invention belongs to the technical field of hydrogen fuel vehicle tail gas treatment, and discloses a tail gas post-treatment device and a tail gas emission control method, wherein the tail gas post-treatment device comprises an exhaust manifold, a DOC device, an SCR device, a silencer and an ECU unit, one end of the exhaust manifold is connected to an exhaust port of a hydrogen engine, and an exhaust regulating valve is arranged on the exhaust manifold; the other end of the exhaust manifold is connected with a DOC device which is positioned at the downstream of the exhaust regulating valve; the SCR device is arranged at the downstream of the DOC device and is connected with a solid ammonia storage device; the silencer is arranged at the output end of the SCR device; the ECU unit is electrically connected with the exhaust regulating valve, the DOC device, the SCR device, the solid ammonia gas storage device and the silencer. The invention can perform catalytic reduction on oxynitride in the tail gas, and reduce the pollution of the tail gas to the environment.

Description

Tail gas post-treatment device and tail gas emission control method

Technical Field

The invention relates to the technical field of hydrogen fuel vehicle tail gas treatment, in particular to a tail gas post-treatment device and a tail gas emission control method.

Background

Hydrogen energy is one of main directions of carbon emission reduction and carbon neutralization, and has an important position in a renewable energy utilization strategy, a direct injection hydrogen engine is a leading-edge technology for hydrogen energy utilization, the hydrogen engine utilizes a lean combustion technology to save energy and reduce emission, the lean combustion technology can effectively reduce the knocking tendency in the combustion process of the engine, and simultaneously can reduce the combustion temperature and improve the heat efficiency of the engine, but the emission of the direct injection hydrogen engine contains completely unburnt hydrogen, hydrocarbon, carbon monoxide, carbon oxide and the like, in order to ensure that the emission of the direct injection hydrogen engine meets the emission regulation requirements, an exhaust gas post-treatment device is usually additionally arranged, the exhaust gas post-treatment device comprises a DOC device and an SCR post-treatment device, namely a DOC (diesel Oxidation catalysts), which can reduce the emission of the carbon monoxide and the hydrocarbon by more than 90 percent, and an SCR (selective Catalytic reduction), which is a selective Catalytic reduction device, can reduce 95% to 99% nitrogen oxide, nevertheless the urea injection pipeline in the current SCR aftertreatment device is easy to crystallize and is blockked up, leads to SCR aftertreatment device to lack the reductant and catalytic efficiency to descend or even catalytic failure, leads to in time catalyzing the oxynitrides in the tail gas.

Therefore, an exhaust gas post-treatment device and an exhaust emission control method are needed to solve the above problems.

Disclosure of Invention

One object of the present invention is: the tail gas after-treatment device and the tail gas emission control method are provided to perform catalytic reduction on oxynitride in tail gas and reduce pollution of the tail gas to the environment.

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

in a first aspect, an exhaust gas aftertreatment device is provided, comprising:

one end of the exhaust manifold is connected with an exhaust port of the hydrogen engine, and an exhaust regulating valve is arranged on the exhaust manifold;

the other end of the exhaust manifold is connected with the DOC device, and the DOC device is positioned at the downstream of the exhaust regulating valve;

the SCR device is arranged at the downstream of the DOC device and is connected with a solid ammonia storage device;

a muffler disposed at an output end of the SCR device;

an ECU unit electrically connected with the exhaust gas regulating valve, the DOC device, the SCR device, the solid ammonia storage device, and the muffler.

As an alternative solution, a turbocharger is further disposed on the exhaust manifold, and the turbocharger is located upstream of the exhaust gas regulating valve.

In a second aspect, an exhaust emission control method for controlling exhaust emission of a hydrogen engine is provided, the exhaust emission control method comprising the steps of:

s100, setting lambda of the hydrogen engine;

s200, establishing an oxynitride discharge model, and calculating the ammonia gas injection pulse width of the solid ammonia gas storage device through the oxynitride discharge model in a matching manner;

s300, performing closed-loop control through a detection sensor for detecting oxynitride, and correcting and recording the ammonia gas injection amount of the solid ammonia gas storage device and the hydrogen gas injection amount of a high-pressure injection system through a self-learning controller;

s400, adjusting the air-fuel ratio to enable the air-fuel ratio to adopt a learning value which is stored in the self-learning controller in the closed loop at the previous time.

As an optional technical solution, the step S200 specifically includes the following steps:

s201, after the hydrogen engine is normally started, judging whether a temperature threshold T1 of the hydrogen engine is not smaller than a first preset temperature value, if so, performing a step S202, and if not, performing a step S203;

s202, entering closed-loop control;

and S203, entering open loop control.

As an optional technical solution, after the step S202, the following steps are performed:

and S301, recording the hydrogen injection amount of the high-pressure injection system through the self-learning controller.

As an optional technical solution, after the step S301, the following steps are performed:

s401, adjusting the air-fuel ratio to adopt the learning value stored in the self-learning controller in the step S301.

and S302, according to the air inflow, the self-learning controller corrects and records the hydrogen injection amount of the high-pressure injection system, so that the hydrogen injected by the high-pressure injection system is mixed with air to form mixed gas.

As an optional technical solution, in the step S302, if the hydrogen engine is in a low-load state, the high-pressure injection system injects hydrogen in advance, so that the hydrogen and air form a homogeneous mixed gas; if the hydrogen engine is in a medium-load state, the high-pressure injection system delays the injection of the hydrogen so that the hydrogen and the air form layered mixed gas; if the hydrogen engine is in a high load state, the high-pressure injection system injects hydrogen gas a plurality of times to supply sufficient hydrogen gas.

As an optional technical solution, after the step S302, the following steps are performed:

s402, adjusting the air-fuel ratio to adopt the learning value stored in the self-learning controller in the step S302.

As an optional technical solution, the following steps are performed after the step S203:

and S303, recording the hydrogen injection amount of the high-pressure injection system through the self-learning controller.

As an optional technical solution, after the step S303, the following steps are performed:

and S403, adjusting the air-fuel ratio to adopt the learning value stored in the self-learning controller in the closed loop at the previous time.

As an optional technical solution, the step 300 specifically includes the following steps:

s304, after the hydrogen engine is started, judging whether the temperature threshold T2 of the solid ammonia storage device is larger than a second preset temperature value, if so, performing a step S305, otherwise, performing a step S306;

s305, heating the solid ammonia storage device to a first preset temperature value so as to decompose the strontium octa-ammine chloride in the solid ammonia storage device into strontium ammine chloride and ammonia;

and S306, performing open-loop control to increase the load of the hydrogen engine.

s307, if the temperature threshold T2 of the solid ammonia gas storage device is larger than a second preset temperature value, judging whether the exhaust emission M of the exhaust gas flowing through the SCR device is larger than a first preset flow value, if so, performing a step S308, and if not, performing a step S309;

s308, heating the solid ammonia storage device to a second preset temperature value so as to decompose the strontium chloride ammine in the solid ammonia storage device into strontium chloride and ammonia;

and S309, performing open-loop control to increase the load of the hydrogen engine.

As an optional technical solution, after the step 308, the following steps are further included:

s3081, the ammonia gas enters the metering and spraying module to realize closed-loop control under the condition of gas fluctuation pressure.

As an optional technical solution, the following steps are further included after the step 308:

and S3082, performing closed-loop control on the air-fuel ratio, and performing self-adaptive learning through the self-learning controller.

The invention has the beneficial effects that:

the invention provides a tail gas post-treatment device and a tail gas emission control method, wherein the tail gas post-treatment device is arranged at an exhaust port of a hydrogen engine, hydrogen and air are mixed and combusted in the hydrogen engine, and the generated tail gas is treated by the tail gas post-treatment device and then is discharged so as to prevent harmful substances in the tail gas from polluting the air; the exhaust regulating valve can regulate the flow of the tail gas in the exhaust manifold; when tail gas passes through the DOC device, carbon monoxide and hydrocarbon in the tail gas are removed, the tail gas continuously flows downstream and passes through the SCR device, the solid ammonia storage device can be used for heating at different degrees according to the flow of the tail gas, if the nitrogen oxides in the tail gas are less, the heating temperature of the solid ammonia storage device is lower, solid strontium octa-ammine chloride is decomposed into strontium ammine chloride and ammonia gas, the ammonia gas enters the SCR device through the injection pipeline to catalyze the nitrogen oxides in the tail gas, nitrogen in the nitrogen oxides is catalyzed into harmless nitrogen gas, and the ammonia gas can not be crystallized and solidified at normal temperature, so an injection pipeline between the solid ammonia storage device and the SCR device can not be blocked, if more nitrogen oxides are in the tail gas, the heating temperature of the solid ammonia storage device is higher, and the solid strontium octa-ammine chloride is decomposed into strontium chloride and ammonia gas, the generated ammonia gas can not block an injection pipeline, so that the catalytic efficiency of oxynitride of tail gas is ensured; the tail gas after catalytic reduction is silenced by a silencer and is discharged from the output end of the SCR device, so that the noise is reduced.

Drawings

The invention is explained in further detail below with reference to the figures and examples;

FIG. 1 is a structural layout diagram of an exhaust gas aftertreatment device according to an embodiment;

FIG. 2 is a flowchart illustrating an exemplary method for controlling exhaust emissions.

In the figure:

100. a hydrogen engine;

1. an exhaust manifold; 2. an exhaust gas regulating valve; 3. a DOC device; 4. an SCR device; 5. a solid ammonia storage device; 6. a muffler; 7. an ECU unit; 8. a turbocharger.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. 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, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. 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 present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, it is to be understood that the terms "upper," "lower," "left," "right," and the like are based on the orientation or positional relationship shown in the drawings for convenience in description and simplicity of operation, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the present invention. Furthermore, the terms "first" and "second" are used merely for descriptive purposes and are not intended to have a special meaning.

In the description herein, references to the description of "an embodiment," "an example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

As shown in fig. 1, the present embodiment provides an exhaust gas aftertreatment device including an exhaust manifold 1, a DOC device 3, an SCR device 4, a muffler 6, and an ECU unit 7, one end of the exhaust manifold 1 being connected to an exhaust port of a hydrogen engine 100, the exhaust manifold 1 being provided with an exhaust gas regulating valve 2; the other end of the exhaust manifold 1 is connected to a DOC device 3, and the DOC device 3 is positioned at the downstream of the exhaust regulating valve 2; the SCR device 4 is arranged at the downstream of the DOC device 3, and the SCR device 4 is connected with a solid ammonia storage device 5; the muffler 6 is arranged at the output end of the SCR device 4; the ECU unit 7 is electrically connected to the exhaust gas control valve 2, the DOC device 3, the SCR device 4, the solid ammonia storage device 5, and the muffler 6.

Specifically, the ECU Unit 7 is an Electronic Control Unit, i.e., an Electronic Control Unit, also called a vehicle computer or a vehicle-mounted computer, and is composed of a microcontroller, a memory, an input/output interface, an analog-to-digital converter, and a large-scale integrated circuit such as a shaping circuit and a driving circuit, which is an existing product.

The existing SCR aftertreatment device mostly uses urea solution as a catalyst, and in some low-temperature environments such as cold winter, the urea solution may crystallize, so that the SCR aftertreatment device cannot catalyze nitrogen oxides in the exhaust gas discharged from the hydrogen engine 100 timely and effectively. As is known in the art, urea solutions freeze in an environment at-11 ℃.

Specifically, the exhaust gas post-treatment device of the present embodiment is installed at an exhaust port of the hydrogen engine 100, hydrogen gas and air are mixed and combusted in the hydrogen engine 100, and the generated exhaust gas is treated by the exhaust gas post-treatment device and then discharged, so as to prevent harmful substances in the exhaust gas from polluting the air; the exhaust gas regulating valve 2 can regulate the flow rate of the exhaust gas in the exhaust manifold 1; when the tail gas passes through the DOC device 3, carbon monoxide and hydrocarbon in the tail gas are removed, the tail gas continuously flows downstream and passes through the SCR device 4, the solid ammonia storage device 5 can be heated to different degrees according to the flow rate of the tail gas, if the nitrogen oxides in the tail gas are less, the heating temperature of the solid ammonia storage device 5 is lower, the solid strontium octa-ammine chloride is decomposed into strontium ammine chloride and ammonia gas, the ammonia gas enters the SCR device 4 through the injection pipeline to catalyze the nitrogen oxides in the tail gas, nitrogen in the nitrogen oxides is catalyzed into harmless nitrogen, the injection pipeline between the solid ammonia storage device 5 and the SCR device 4 cannot be blocked because the ammonia gas cannot be crystallized and solidified at normal temperature, if the nitrogen oxides in the tail gas are more, the heating temperature of the solid ammonia storage device 5 is higher, and the solid strontium octa-ammine chloride is decomposed into strontium chloride and ammonia gas, the generated ammonia gas can not block an injection pipeline, so that the catalytic efficiency of oxynitride of tail gas is ensured; the tail gas after catalytic reduction is silenced through a silencer 6 and is discharged from the output end of the SCR device 4, so that the noise is reduced.

Optionally, a turbocharger 8 is further disposed on the exhaust manifold 1, the turbocharger 8 is located upstream of the exhaust gas regulating valve 2, and the turbocharger 8 is used for enhancing the flow pressure of the exhaust gas.

The hydrogen has the advantages of high quality and heat value, high combustion speed, good diffusivity, wide combustible concentration range and the like, and is suitable for being used as a fuel of the hydrogen engine 100, oxynitride in the hydrogen engine 100 mainly comes from oxidation reaction of nitrogen and oxygen in air in a high-temperature oxygen-enriched environment, part of oxynitride is generated in a flame front, and the generation amount of oxynitride is mainly related to temperature in a lean mixture zone, namely the oxynitride generated by the hydrogen engine 100 under different temperature conditions is different in speed, and is mainly related to oxygen concentration in a rich mixture zone, namely the oxynitride generated by the hydrogen engine 100 absorbing a small amount of air and absorbing a large amount of air is different in speed, so that the exhaust emission can not be completely and accurately controlled only by improving an exhaust aftertreatment device.

In order to accurately control the pollutants in the exhaust gas, the present embodiment further provides an exhaust emission control method, the exhaust emission control method of the present embodiment combines the exhaust gas after-treatment device of the present embodiment to control the exhaust emission of the hydrogen engine 100, on the basis of controlling and purifying gaseous exhaust pollutants through efficient combustion in the cylinder of the hydrogen engine 100, combines the DOC device 3 in the exhaust gas after-treatment device of the present embodiment to treat residual hydrogen and carbon monoxide, and utilizes the heat generated by the oxidation reaction in the DOC device 3 to flow into the SCR device 4, so as to provide certain assistance for the reduction reaction performed by the oxynitride.

As shown in fig. 2, the method for controlling exhaust emission of the present embodiment includes the following steps.

S100, λ of the hydrogen engine 100 is set. The lambda of the hydrogen engine 100 is the ratio of the mass of air actually supplied to the mass of air theoretically required when 1 kg of hydrogen fuel is burned, and the factors that affect the lambda include the load on the vehicle, i.e., the higher the load on the vehicle, the higher the output power of the hydrogen engine 100, and the more oxygen that needs to be consumed by intake. When the lambda of the hydrogen engine 100 is equal to 1 or close to 1, the hydrogen engine is an oxynitride generation region, at this time, the combustion speed of hydrogen is high under an equivalent ratio, the water vapor content is high, the improvement of the thermal efficiency is not facilitated, the production amount of oxynitride of the hydrogen engine 100 can be reduced through a lean burn process, the thermal efficiency is ensured, but the required air intake amount is large, the exhaust flow rate of the hydrogen engine 100 exhausted to the exhaust manifold 1 is also increased, the production rate of oxynitride is changed, namely, the emission amount of oxynitride is increased, and the requirement on an exhaust gas post-treatment device is improved. When the lambda of the hydrogen engine 100 is greater than 2.5, and the emission of nitrogen oxides is less than 0.1g/kWh, the unburned hydrogen content of the hydrogen engine 100 under the same load condition is increased by lean combustion, so that the hydrogen and carbon monoxide are oxidized by the DOC device 3, and the SCR device 4 is provided to ensure good economy and dynamic performance of the hydrogen engine 100.

S200, establishing an oxynitride discharge model, and calculating the ammonia gas injection pulse width of the solid ammonia gas storage device 5 through the oxynitride discharge model in a matching manner.

And S300, performing closed-loop control through a detection sensor for detecting oxynitride, and correcting and recording the ammonia gas injection amount of the solid ammonia gas storage device 5 and the hydrogen gas injection amount of the high-pressure injection system through a self-learning controller.

The method for controlling exhaust emission of the present embodiment controls the source of nitrogen oxide generation, and performs catalytic reduction on the generated nitrogen oxide. After lambda of the hydrogen engine 100 is set, an oxynitride discharge model is established, and the oxynitride discharge model is matched with and calculates the ammonia gas injection pulse width of the solid ammonia gas storage device 5, for example, when the vehicle is running on a different road surface, the output of the hydrogen engine 100 is different, the output of the hydrogen engine 100 is large in the uphill state, the amount of oxygen to be taken in is large, in the flat traveling state, the output of the hydrogen engine 100 is small, the amount of oxygen to be taken in is small, and the discharge amount of nitrogen oxide is different when different amounts of oxygen are taken in, and therefore the amount of ammonia gas required to be supplied from the solid ammonia gas storage device 5 is also different, therefore, the present embodiment establishes an nox emission model of the hydrogen engine 100, and matching a proper amount of ammonia gas according to the nitrogen oxide compound emission model so as to completely reduce the nitrogen oxide compound and avoid the ammonia gas from escaping due to excessive supply of the ammonia gas.

Since the vehicle may run uphill or downhill or at an increased speed or a reduced speed during the running process, the output power of the hydrogen engine 100 may vary, the amount of nitrogen oxide discharged may vary, ammonia may need to be matched with the variation of nitrogen oxide, therefore, in the present embodiment, the nitrogen oxide is closed-loop controlled by the detection sensor, if the ammonia gas can satisfy the matching of the nitrogen oxide, the self-learning controller records lambda of the hydrogen engine 100, the amount of nitrogen oxides discharged and the amount of ammonia discharged, that is, λ of the hydrogen engine 100, the discharge amount of nitrogen oxides, and the discharge amount of ammonia are all learning values, and if ammonia cannot satisfy the matching of nitrogen oxides, open-loop control is performed, that is, the self-learning controller records λ of the hydrogen engine 100, the discharge amount of nitrogen oxides, and the discharge amount of ammonia gas, but the air-fuel ratio still adopts the learning value stored in the self-learning controller at the time of the previous closed loop. The air-fuel ratio is the ratio of the mass of air to the mass of fuel, and in this embodiment, the air-fuel ratio is the ratio of the mass of air to the mass of hydrogen.

Optionally, step S200 specifically includes the following steps.

S201, after the hydrogen engine 100 is normally started, it is determined whether the temperature threshold T1 of the hydrogen engine 100 is not less than a first preset temperature value, if so, step S202 is performed, and if not, step S203 is performed.

And S202, entering closed-loop control. The closed-loop control is to make the supply amount of hydrogen gas satisfy the set λ during the operation of the hydrogen engine 100 with the target λ set in the ECU unit 7.

And S203, entering open loop control. After the open loop control is performed, the next step is performed without information feedback.

Before the hydrogen engine 100 is normally started in step S201, the hydrogen engine 100 is started, and the air intake amount of the hydrogen engine 100 is controlled by the throttle body in accordance with the ignition timing. The ignition timing is the end of the compression stroke of the hydrogen engine 100, and when the piston reaches the top of the stroke, the ignition system provides high-pressure spark to the spark plug to ignite the compressed mixed gas in the cylinder to produce work.

Specifically, the maximum value of the carrier center temperature of the hydrogen engine 100 is the temperature threshold of the hydrogen engine 100, and the carrier center temperature of the hydrogen engine 100 has an important influence on the production amount of nitrogen oxides, so step S201 needs to determine whether the temperature threshold of the hydrogen engine 100 is not less than a first preset value, if so, it means that the production amount of nitrogen oxides is mainly related to temperature, and the adjustment requirement is satisfied, i.e., closed-loop control is performed to reduce the production amount of nitrogen oxides, and if not, open-loop control is performed, and a learning value is recorded by a self-learning controller, the learning value serves as an effective regulation part of a nitrogen emission model of nitrogen oxides, the production amount of oxygen compounds is not related to temperature, and the learning value serves as an ineffective regulation part of the nitrogen oxide emission model.

Optionally, after step S202, the following steps are performed: and S301, recording the hydrogen injection amount of the high-pressure injection system through the self-learning controller.

Optionally, after step S301, the following steps are performed: s401, the air-fuel ratio is adjusted to adopt the learning value stored in the self-learning controller in the step S301.

Specifically, after step S202, regarding the hydrogen injection amount of the high-pressure injection system as an effective adjustment portion of the nox emission model, it is necessary to record the learning value by the self-learning controller and adjust the air-fuel ratio with respect to the learning value so that the high-pressure injection system can accurately control the amount of hydrogen emission when a similar situation is encountered next time.

Optionally, after step S202, the following steps are performed: and S302, according to the air inflow, the self-learning controller corrects and records the hydrogen injection amount of the high-pressure injection system, so that the hydrogen injected by the high-pressure injection system is mixed with air to form mixed gas.

Alternatively, in step S302, if the hydrogen engine 100 is in a low-load state, the high-pressure injection system injects hydrogen in advance, so that the hydrogen and air form a homogeneous mixed gas; if the hydrogen engine 100 is in a medium-load state, the high-pressure injection system delays the injection of the hydrogen gas, so that the hydrogen gas and the air form layered mixed gas; if the hydrogen engine 100 is in a high load state, the high-pressure injection system injects hydrogen gas a plurality of times to supply sufficient hydrogen gas.

Optionally, the following steps are performed after step S302: s402, adjusting the air-fuel ratio to adopt the learning value stored in the self-learning controller in the step S302.

Optionally, after step S203, the following steps are performed: and S303, recording the hydrogen injection amount of the high-pressure injection system through the self-learning controller.

Optionally, after step S303, the following steps are performed: and S403, adjusting the air-fuel ratio to adopt the learning value stored in the self-learning controller in the closed loop at the previous time.

Optionally, step 300 specifically includes the following steps: s304, after the hydrogen engine 100 is started, it is determined whether the temperature threshold T2 of the solid ammonia storage device 5 is greater than a second preset temperature value, if so, step S305 is performed, and if not, step S306 is performed.

S305, heating the solid ammonia storage device 5 to a first preset temperature value so as to decompose the strontium octa-ammine chloride in the solid ammonia storage device 5 into strontium ammine chloride and ammonia.

S306, open-loop control is performed to increase the load on the hydrogen engine 100.

Specifically, when the temperature threshold T2 of the solid ammonia storage device 5 is greater than the second preset temperature value, the solid ammonia storage device 5 is heated to 60 degrees celsius, so that the strontium octa-ammine chloride in the solid ammonia storage device 5 is decomposed into strontium ammine chloride and ammonia, and if the temperature threshold T2 of the solid ammonia storage device 5 is less than the second preset temperature value, open-loop control is performed, and a driver on the vehicle steps on an accelerator, so that the output power of the hydrogen engine 100 is increased.

Optionally, step 300 further includes the following steps.

And S307, if the temperature threshold T2 of the solid ammonia storage device 5 is greater than the second preset temperature value, judging whether the exhaust emission M flowing through the SCR device 4 is greater than the first preset flow value, if so, performing the step S308, and if not, performing the step S309.

And S308, heating the solid ammonia storage device 5 to a second preset temperature value so as to decompose strontium chloride ammine in the solid ammonia storage device 5 into strontium chloride and ammonia.

S309, open-loop control is performed to increase the load on the hydrogen engine 100.

Optionally, after step 308, the following steps are further included: s3081, the ammonia gas enters the metering and spraying module to realize closed-loop control under the condition of gas fluctuation pressure.

Optionally, after step 308, the following steps are further included: and S3082, performing closed-loop control on the air-fuel ratio, and performing self-adaptive learning through a self-learning controller.

Specifically, when the temperature threshold T2 of the solid ammonia storage device 5 is greater than the second preset temperature value and the exhaust emission M is greater than the first preset flow value, the high-pressure ammonia in the solid ammonia storage device 5 enters the metering and injecting module, so that closed-loop control under the condition of fluctuating pressure is realized, and the requirement on the injection precision of the reducing agent is met. Because the nitrogen oxides generated by the hydrogen engine 100 under different road conditions are different, for example, when climbing a slope, large power is required, more nitrogen oxides are generated, and when going downhill, small power is output, less nitrogen oxides are generated, so that air pressure fluctuation is caused.

The tail gas emission control method of this embodiment is when the control releases the ammonia, need not carry out hydrolysis reaction, can directly spout the ammonia into SCR device 4, there is not urea aqueous solution crystallization problem, also can not produce the deposit in tail gas aftertreatment device's blast pipe, solid ammonia storage device 5 directly spouts the ammonia to SCR device 4 in with oxynitride according to oxynitrides emission model and takes place the reaction, because the injection volume of ammonia obtains accurate control, reduce SCR device 4's the temperature of igniting, solve the ammonia escape problem that the ammonia supply is too much and leads to simultaneously, avoid the ammonia to cause secondary pollution to the atmospheric environment.

In addition, the foregoing is only the preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An exhaust gas aftertreatment device, comprising:

the exhaust manifold (1), one end of the said exhaust manifold (1) is connected to the exhaust outlet of the hydrogen engine (100), there are exhaust regulating valves (2) on the said exhaust manifold (1);

a DOC device (3), the other end of the exhaust manifold (1) is connected to the DOC device (3), and the DOC device (3) is positioned at the downstream of the exhaust regulating valve (2);

the SCR device (4) is arranged at the downstream of the DOC device (3), and the SCR device (4) is connected with a solid ammonia storage device (5);

a muffler (6), said muffler (6) being disposed at an output of said SCR device (4);

an ECU unit (7), the ECU unit (7) being electrically connected with the exhaust gas regulating valve (2), the DOC device (3), the SCR device (4), the solid ammonia storage device (5), and the muffler (6).

2. The exhaust gas aftertreatment device according to claim 1, characterized in that a turbocharger (8) is further arranged on the exhaust manifold (1), the turbocharger (8) being located upstream of the exhaust gas regulating valve (2).

3. An exhaust emission control method for controlling exhaust emission of a hydrogen engine (100), comprising the steps of:

s100, setting lambda of the hydrogen engine (100);

s200, establishing an oxynitride discharge model, and calculating the ammonia gas injection pulse width of the solid ammonia gas storage device (5) through the oxynitride discharge model in a matching manner;

s300, performing closed-loop control through a detection sensor for detecting oxynitride, and correcting and recording the ammonia gas injection amount of the solid ammonia gas storage device (5) and the hydrogen gas injection amount of a high-pressure injection system through a self-learning controller;

4. The method according to claim 3, wherein the step S200 specifically comprises the steps of:

s201, after the hydrogen engine (100) is normally started, judging whether a temperature threshold T1 of the hydrogen engine (100) is not less than a first preset temperature value, if so, performing a step S202, and if not, performing a step S203;

s202, entering closed-loop control;

and S203, entering open loop control.

5. The exhaust emission control method according to claim 4, wherein the following steps are performed after the step S202:

6. The exhaust emission control method according to claim 5, characterized in that the following step is performed after the step S301:

7. The exhaust emission control method according to claim 4, wherein the following steps are performed after the step S202:

and S302, according to the air intake amount, the self-learning controller corrects and records the hydrogen injection amount of the high-pressure injection system, so that the hydrogen injected by the high-pressure injection system is mixed with air to form mixed gas.

8. The exhaust emission control method according to claim 7, wherein in step S302, if the hydrogen engine (100) is in a low load state, the high-pressure injection system injects hydrogen gas in advance so that the hydrogen gas and air form a homogeneous mixed gas; if the hydrogen engine (100) is in a medium-load state, the high-pressure injection system delays to inject hydrogen so that the hydrogen and air form layered mixed gas; if the hydrogen engine (100) is in a high load state, the high-pressure injection system injects hydrogen gas a plurality of times to supply sufficient hydrogen gas.

9. The exhaust emission control method according to claim 8, wherein the following steps are performed after the step S302:

10. The exhaust emission control method according to claim 4, wherein the following step is performed after the step S203:

11. The exhaust emission control method according to claim 10, wherein the following step is performed after the step S303:

12. The method of claim 3, wherein the step 300 comprises the steps of:

s304, after the hydrogen engine (100) is started, judging whether the temperature threshold T2 of the solid ammonia storage device (5) is larger than a second preset temperature value, if so, performing a step S305, and if not, performing a step S306;

s305, heating the solid ammonia storage device (5) to a first preset temperature value so as to decompose the strontium octa-ammine chloride in the solid ammonia storage device (5) into strontium ammine chloride and ammonia;

s306, open-loop control is performed to increase the load of the hydrogen engine (100).

13. The method of claim 12, wherein the step 300 further comprises the steps of:

s307, if the temperature threshold T2 of the solid ammonia storage device (5) is larger than a second preset temperature value, judging whether the exhaust emission M of the exhaust gas flowing through the SCR device (4) is larger than a first preset flow value, if so, performing a step S308, otherwise, performing a step S309;

s308, heating the solid ammonia storage device (5) to a second preset temperature value so as to decompose the strontium chloride ammine in the solid ammonia storage device (5) into strontium chloride and ammonia;

s309, open-loop control is performed to increase the load of the hydrogen engine (100).

14. The exhaust emission control method according to claim 13, further comprising, after the step 308, the steps of:

15. The exhaust emission control method according to claim 13, further comprising, after the step 308, the steps of: