CN113153501A

CN113153501A - Urea injection amount control method and related equipment

Info

Publication number: CN113153501A
Application number: CN202110495739.4A
Authority: CN
Inventors: 谭治学; 杨新达; 胡涛; 徐昊洋; 孙明峰
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2021-05-07
Filing date: 2021-05-07
Publication date: 2021-07-23
Anticipated expiration: 2041-05-07
Also published as: CN113153501B

Abstract

The invention provides a urea injection quantity control method and related equipment, which are applied to a double-SCR system, wherein the double-SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series, the first SCR mixer comprises a first urea nozzle, the second SCR mixer comprises a second urea nozzle, the method respectively determines a first urea distribution proportion of a first SCR mixer and a second urea distribution proportion of a second SCR mixer in the double SCR system through a first crystal boundary of the first SCR mixer and a second crystal boundary of the second SCR mixer, and further determines a first urea injection amount of the first SCR mixer based on the first urea distribution ratio and the required urea injection total amount, and determining the second urea injection amount of the second SCR mixer according to the second urea distribution proportion and the required urea injection total amount, and reasonably utilizing the anti-crystallization capacity of the first SCR mixer and the second SCR mixer in the double SCR system to avoid crystallization.

Description

Urea injection amount control method and related equipment

Technical Field

The disclosure relates to the technical field of engine aftertreatment, in particular to a urea injection quantity control method and related equipment.

Background

Nitrogen oxides are generated during the use of diesel engines, and currently, the nitrogen oxides are mainly converted into pollution-free nitrogen by injecting urea by installing an SCR (Selective catalytic Reduction) in an aftertreatment system of the diesel engine.

Currently, to alleviate the injection loading pressure of a single SCR mixer, a dual SCR system comprising two SCR mixers may be designed. Therefore, there is a need for a urea injection scheme that prevents SCR mixer crystallization based on a dual SCR system design.

Disclosure of Invention

In view of the above problems, the present disclosure provides a method and related apparatus for controlling an amount of injected urea, which overcomes or at least partially solves the above problems, and the technical solution is as follows:

a urea injection quantity control method is applied to a double SCR system, the double SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series, the first SCR mixer comprises a first urea nozzle, the second SCR mixer comprises a second urea nozzle, and the urea injection quantity control method comprises the following steps:

obtaining an exhaust flow rate of the engine;

obtaining a first exhaust temperature upstream of the first urea nozzle and a second exhaust temperature upstream of the second urea nozzle;

determining a first crystal boundary of the first SCR mixer based on the exhaust flow rate and the first exhaust temperature; determining a second crystal boundary of the second SCR mixer based on the exhaust flow rate and the second exhaust temperature;

determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer according to the first crystal boundary and the second crystal boundary;

obtaining the total required urea injection amount of the engine under the current working condition;

determining a first urea injection quantity of the first SCR mixer according to the total required urea injection quantity and the first urea distribution proportion; and determining a second urea injection quantity of the second SCR mixer according to the total required urea injection quantity and the second urea distribution proportion.

Optionally, the method further includes:

and under the condition that the first urea injection quantity and the second urea injection quantity are not less than a first preset injection quantity, controlling the first SCR mixer to inject urea through the first urea nozzle according to the first urea injection quantity, and controlling the second SCR mixer to inject urea through the second urea nozzle according to the second urea injection quantity.

Optionally, the first urea nozzle is located upstream of the second urea nozzle, the method further comprising:

and under the condition that the first urea injection amount and/or the second urea injection amount are/is smaller than a second preset injection amount, controlling the first SCR mixer to inject urea through the first urea nozzle according to the total required urea injection amount, and controlling the second urea nozzle of the second SCR mixer to stop injecting urea.

Optionally, the determining a first crystallization boundary of the first SCR mixer based on the exhaust flow rate and the first exhaust temperature includes:

determining a third crystallization boundary in a first preset crystallization boundary MAP corresponding to the first SCR mixer according to the exhaust flow and the first exhaust temperature;

according to the environment temperature of the double SCR system, performing curve correction on the third crystallization boundary to obtain a first crystallization boundary of the first SCR mixer;

and/or said determining a second crystal boundary of said secondary second SCR mixer based on said exhaust flow rate and said second exhaust temperature comprises:

determining a fourth crystal boundary in a second preset crystal boundary MAP corresponding to the second SCR mixer according to the exhaust flow and the second exhaust temperature;

and performing curve correction on the fourth crystal boundary according to the ambient temperature of the double SCR system to obtain a second crystal boundary of the second SCR mixer.

Optionally, the determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer according to the first crystal boundary and the second crystal boundary includes:

calculating the sum of the first crystal boundary and the second crystal boundary to obtain a total crystal value;

determining a ratio of the first crystallization boundary to the total crystallization value as a first urea distribution ratio of the first SCR mixer;

determining a ratio of the second crystallization boundary to the total crystallization value as a second urea split ratio for the second SCR mixer.

Optionally, the determining a first urea injection amount of the first SCR mixer according to the total required urea injection amount and the first urea distribution ratio includes:

determining a first urea injection quantity of the first SCR mixer by multiplying the total required urea injection quantity by the first urea distribution proportion;

and/or, the determining a second urea injection amount of the second SCR mixer according to the total required urea injection amount and the second urea distribution ratio includes:

and determining the product of the total required urea injection amount and the second urea distribution proportion as a second urea injection amount of the second SCR mixer.

A urea injection amount control device applied to a dual SCR system including a first SCR mixer and a second SCR mixer arranged in series, the first SCR mixer including a first urea nozzle, the second SCR mixer including a second urea nozzle, the urea injection amount control device comprising: an exhaust gas flow rate obtaining unit, an exhaust gas temperature obtaining unit, a first crystallization boundary determining unit, a second crystallization boundary determining unit, a urea distribution ratio determining unit, a required urea injection total amount obtaining unit, a first urea injection amount determining unit, and a second urea injection amount determining unit,

the exhaust flow obtaining unit is used for obtaining the exhaust flow of the engine;

the exhaust gas temperature obtaining unit is used for obtaining a first exhaust gas temperature upstream of the first urea nozzle and a second exhaust gas temperature upstream of the second urea nozzle;

the first crystallization boundary determining unit is used for determining a first crystallization boundary of the first SCR mixer according to the exhaust gas flow and the first exhaust gas temperature;

the second crystal boundary determining unit is configured to determine a second crystal boundary of the second SCR mixer according to the exhaust gas flow rate and the second exhaust gas temperature;

the urea distribution ratio determining unit is configured to determine a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer based on the first crystal boundary and the second crystal boundary;

the required urea injection total quantity obtaining unit is used for obtaining the required urea injection total quantity of the engine under the current working condition;

the first urea injection quantity determining unit is used for determining a first urea injection quantity of the first SCR mixer according to the total required urea injection quantity and the first urea distribution proportion;

the second urea injection quantity determining unit is used for determining a second urea injection quantity of the second SCR mixer according to the total required urea injection quantity and the second urea distribution proportion.

Optionally, the apparatus further comprises: a first urea injection control unit for controlling the injection of urea,

and the first urea injection control unit is used for controlling the first SCR mixer to inject urea through the first urea nozzle according to the first urea injection amount and controlling the second SCR mixer to inject urea through the second urea nozzle according to the second urea injection amount under the condition that the first urea injection amount and the second urea injection amount are not smaller than a first preset injection amount.

A computer-readable storage medium, having stored thereon a program which, when executed by a processor, implements a urea injection amount control method as recited in any of the above.

An electronic device comprising at least one processor, and at least one memory connected to the processor, a bus; the processor and the memory complete mutual communication through the bus; the processor is configured to invoke program instructions in the memory to perform a urea injection amount control method as described in any one of the above.

By means of the technical scheme, the urea injection quantity control method and the related equipment are applied to a double-SCR system, the double-SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series, the first SCR mixer comprises a first urea nozzle, the second SCR mixer comprises a second urea nozzle, and the urea injection quantity control method can obtain the exhaust flow of an engine; obtaining a first exhaust temperature upstream of the first urea nozzle and a second exhaust temperature upstream of the second urea nozzle; determining a first crystallization boundary of the first SCR mixer based on the exhaust flow rate and the first exhaust temperature; determining a second crystal boundary of a second SCR mixer based on the exhaust flow and the second exhaust temperature; determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer according to the first crystal boundary and the second crystal boundary; obtaining the total urea injection quantity required by the engine under the current working condition; determining a first urea injection quantity of a first SCR mixer according to the total required urea injection quantity and the first urea distribution proportion; a second urea injection amount of the second SCR mixer is determined based on the total required urea injection amount and the second urea distribution ratio. According to the method, the first urea distribution proportion of the first SCR mixer and the second urea distribution proportion of the second SCR mixer in the double-SCR system are respectively determined through the first crystal boundary of the first SCR mixer and the second crystal boundary of the second SCR mixer, the first urea injection amount of the first SCR mixer is further determined according to the first urea distribution proportion and the required urea injection total amount, the second urea injection amount of the second SCR mixer is determined according to the second urea distribution proportion and the required urea injection total amount, and crystallization is avoided by reasonably utilizing the anti-crystallization capacity of the first SCR mixer and the anti-crystallization capacity of the second SCR mixer in the double-SCR system.

The foregoing description is only an overview of the technical solutions of the present disclosure, and the embodiments of the present disclosure are described below in order to make the technical means of the present disclosure more clearly understood and to make the above and other objects, features, and advantages of the present disclosure more clearly understandable.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the disclosure. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic diagram illustrating one embodiment of a method for controlling an amount of injected urea provided by an embodiment of the present disclosure;

FIG. 2 is a schematic diagram illustrating another embodiment of a method for controlling an amount of injected urea provided by an embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating another embodiment of a method for controlling an amount of injected urea provided by an embodiment of the present disclosure;

FIG. 4 is a schematic diagram illustrating another embodiment of a method for controlling an amount of injected urea provided by an embodiment of the present disclosure;

FIG. 5 is a schematic diagram illustrating another embodiment of a method for controlling an amount of injected urea provided by an embodiment of the present disclosure;

FIG. 6 is a schematic diagram illustrating another embodiment of a method for controlling an amount of injected urea provided by an embodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating a control logic for controlling injection amount of dual urea injectors in a dual SCR system according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram illustrating a urea injection amount control apparatus according to an embodiment of the present disclosure.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The urea injection quantity control method provided by the embodiment of the disclosure is applied to a double SCR system, and the double SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series. The first SCR mixer includes a first urea nozzle and the second SCR mixer includes a second urea nozzle.

As shown in fig. 1, a schematic diagram of an implementation manner of a urea injection quantity control method provided by an embodiment of the present disclosure may include:

and S100, obtaining the exhaust flow of the engine.

It is understood that the disclosed embodiments may obtain the exhaust flow of the engine by installing an exhaust flow sensor in the exhaust duct of the engine.

S200, obtaining a first exhaust temperature at the upstream of the first urea nozzle and a second exhaust temperature at the upstream of the second urea nozzle.

The disclosed embodiments may mount a temperature sensor upstream of the first urea nozzle, by which a first exhaust temperature upstream of the first urea nozzle is obtained. The disclosed embodiments may mount a temperature sensor upstream of the second urea nozzle, by which a second exhaust temperature upstream of the second urea nozzle is obtained. It will be appreciated that where the first urea nozzle is arranged in series with the second urea nozzle, embodiments of the present disclosure may install a temperature sensor between the first urea nozzle and the second urea nozzle by which a second exhaust temperature is obtained upstream of the second urea nozzle when the first urea nozzle is upstream of the second urea nozzle.

S300, determining a first crystal boundary of the first SCR mixer according to the exhaust flow and the first exhaust temperature.

The disclosed embodiments may calibrate the crystallization boundary MAP of the first SCR mixer in advance according to the exhaust flow rate of the engine and the first exhaust temperature upstream of the first urea injection nozzle as control variables.

Alternatively, in practical applications, the obtained exhaust flow rate and the first exhaust temperature may be used as current conditions, and the first crystal boundary corresponding to the current conditions may be determined in the crystal boundary MAP.

It is understood that during practical use of a dual SCR system, there may be extrinsic factors that affect the crystallization boundary of the SCR mixer. The extrinsic factors may include at least one of an ambient temperature, an ambient humidity, and an ambient dust content at which the dual SCR system is located. Therefore, the embodiment of the disclosure can determine the crystal boundary in the crystal boundary MAP corresponding to the SCR mixer according to the exhaust flow and the exhaust temperature upstream of the urea nozzle of the SCR mixer, and then correct the crystal boundary according to the influence of external factors of the environment where the double SCR system is located on the crystal boundary.

Optionally, the crystallization boundary determined according to the crystallization boundary MAP of the first SCR mixer may be used as a theoretical boundary, and a crystallization boundary calibrated by combining the theoretical boundary and the ambient temperature of the dual SCR system is used as an actual boundary, and finally the actual boundary is used as the first crystallization boundary of the first SCR mixer. According to the embodiment of the disclosure, the influence of external factors on the crystal boundary of the first SCR mixer is combined, the crystal boundary determined by the crystal boundary MAP of the first SCR mixer is corrected, and the actual boundary which meets the actual condition is obtained and used as the first crystal boundary of the first SCR mixer, so that the determined first crystal boundary of the first SCR mixer is more accurate.

Alternatively, based on the method shown in fig. 1, as shown in fig. 2, a schematic diagram of another implementation manner of the urea injection quantity control method provided by the embodiment of the present disclosure, step S300 may include:

and S310, determining a third crystallization boundary in a first preset crystallization boundary MAP corresponding to the first SCR mixer according to the exhaust flow and the first exhaust temperature.

And S320, performing curve correction on the third crystallization boundary according to the environment temperature of the double SCR system to obtain a first crystallization boundary of the first SCR mixer.

It is understood that the disclosed embodiments may calibrate the ambient temperature-crystallization boundary correction CURVE (CURVE) diagram in advance according to the relationship between the ambient temperature at which the dual SCR system is located and the crystallization boundary determined according to the crystallization boundary MAP corresponding to the SCR mixer. Therefore, according to the ambient temperature-crystal boundary correction graph, the embodiment of the disclosure may perform curve correction on the third crystal boundary according to the ambient temperature of the dual SCR system, so as to obtain the first crystal boundary of the first SCR mixer. According to the embodiment of the disclosure, the influence of the environment temperature of the double SCR system on the crystallization boundary of the first SCR mixer is combined, and the third crystallization boundary determined by the crystallization boundary MAP of the first SCR mixer is corrected, so that the determined first crystallization boundary of the first SCR mixer is more accurate.

And S400, determining a second crystal boundary of a second SCR mixer according to the exhaust flow and the second exhaust temperature.

The disclosed embodiments may calibrate the crystallization boundary MAP of the second SCR mixer in advance according to the exhaust flow of the engine and the second exhaust temperature upstream of the second urea nozzle as control variables.

Alternatively, in practical applications, the obtained exhaust flow rate and the second exhaust temperature may be used as current conditions, and a second crystal boundary corresponding to the current conditions is determined in the crystal boundary MAP.

Optionally, the crystallization boundary determined according to the crystallization boundary MAP of the second SCR mixer may be used as a theoretical boundary, and the actual boundary is finally used as the second crystallization boundary of the second SCR mixer by using the theoretical boundary and the crystallization boundary calibrated according to the ambient temperature of the dual SCR system as an actual boundary. According to the embodiment of the disclosure, the influence of the external factors on the crystal boundary of the second SCR mixer is combined, the crystal boundary determined by the crystal boundary MAP of the second SCR mixer is corrected, and the actual boundary which meets the actual condition is obtained and used as the second crystal boundary of the second SCR mixer, so that the determined second crystal boundary of the second SCR mixer is more accurate.

Alternatively, as shown in fig. 2, a schematic diagram of another implementation manner of the urea injection quantity control method provided by the embodiment of the present disclosure, step S400 may include:

and S410, determining a fourth crystal boundary in a second preset crystal boundary MAP corresponding to the second SCR mixer according to the exhaust gas flow and the second exhaust gas temperature.

And S420, performing curve correction on the fourth crystal boundary according to the environment temperature of the double SCR system to obtain a second crystal boundary of the second SCR mixer.

It is understood that the disclosed embodiments may calibrate the ambient temperature-crystallization boundary correction CURVE (CURVE) diagram in advance according to the relationship between the ambient temperature at which the dual SCR system is located and the crystallization boundary determined according to the crystallization boundary MAP corresponding to the SCR mixer. Therefore, according to the ambient temperature-crystal boundary correction graph, the curve correction can be performed on the fourth crystal boundary according to the ambient temperature of the dual SCR system, so as to obtain the second crystal boundary of the second SCR mixer. According to the embodiment of the disclosure, the influence of the environment temperature of the double SCR system on the crystal boundary of the second SCR mixer is combined, and the fourth crystal boundary determined by the crystal boundary MAP of the second SCR mixer is corrected, so that the determined second crystal boundary of the second SCR mixer is more accurate.

And S500, determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer according to the first crystal boundary and the second crystal boundary.

Alternatively, the present embodiment may calculate the product of the first crystal boundary and the second crystal boundary to obtain the total crystal value. The ratio of the first crystal boundary to the total crystal value is determined as the first urea split ratio for the first SCR mixer. The ratio of the second crystal boundary to the total crystal value is determined as a second urea split ratio for the second SCR mixer.

Alternatively, based on the method shown in fig. 1, as shown in fig. 3, a schematic diagram of another implementation manner of the urea injection quantity control method provided by the embodiment of the present disclosure, step S500 may include:

and S510, calculating the sum of the first crystal boundary and the second crystal boundary to obtain a total crystal value.

S520, determining the ratio of the first crystal boundary to the total crystal value as the first urea distribution proportion of the first SCR mixer.

And S530, determining the ratio of the second crystal boundary to the total crystal value as a second urea distribution proportion of the second SCR mixer.

According to the embodiment of the disclosure, the crystallization boundaries of the first SCR mixer and the second SCR mixer are used as urea distribution conditions, and the urea distribution proportions of the first SCR mixer and the second SCR mixer are respectively determined, so that the urea distribution proportions determined by the SCR mixers are matched with the anti-crystallization capacity of the SCR mixers, and further, the SCR mixers are prevented from generating crystallization to the greatest extent.

And S600, acquiring the total urea injection quantity required by the engine under the current working condition.

The embodiment of the disclosure can calculate the total amount of the required urea injection according to the working condition parameters of the engine under the current working condition. The operating condition parameters may include at least one of engine speed, cyclic injection quantity, exhaust temperature, exhaust flow, and real-time nox mass flow. It will be appreciated that the specific desired total urea injection amount determination process may be a method of determining the amount of injected urea with reference to existing SCR systems, and the disclosure is not further limited herein.

S700, determining a first urea injection quantity of a first SCR mixer according to the total required urea injection quantity and the first urea distribution proportion.

Alternatively, based on the method shown in fig. 1, as shown in fig. 4, a schematic diagram of another implementation manner of the urea injection quantity control method provided by the embodiment of the present disclosure, step S700 may include:

and S710, determining the product of the total required urea injection amount and the first urea distribution proportion as a first urea injection amount of the first SCR mixer.

And S800, determining a second urea injection quantity of a second SCR mixer according to the total required urea injection quantity and the second urea distribution proportion.

Alternatively, as shown in fig. 4, in another implementation schematic diagram of a urea injection quantity control method provided in an embodiment of the present disclosure, step S800 may include:

and S810, determining the product of the total required urea injection amount and the second urea distribution proportion as a second urea injection amount of the second SCR mixer.

According to the embodiment of the disclosure, the first urea injection amount of the first SCR mixer is determined in the required urea injection amount according to the first urea distribution proportion, and the second urea injection amount of the second SCR mixer is determined in the required urea injection amount according to the second urea distribution proportion, so that the urea injection amount distributed by each SCR mixer is matched with the anti-crystallization capacity of the SCR mixer, and the SCR mixer is prevented from crystallizing due to the fact that a single SCR mixer bears excessive urea injection amount.

The urea injection quantity control method is applied to a double-SCR system, the double-SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series, the first SCR mixer comprises a first urea nozzle, the second SCR mixer comprises a second urea nozzle, and the urea injection quantity control method can obtain the exhaust flow quantity input to the double-SCR system; obtaining a first exhaust temperature upstream of the first urea nozzle and a second exhaust temperature upstream of the second urea nozzle; determining a first crystallization boundary of the first SCR mixer based on the exhaust flow rate and the first exhaust temperature; determining a second crystal boundary of a second SCR mixer based on the exhaust flow and the second exhaust temperature; determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer according to the first crystal boundary and the second crystal boundary; obtaining the total urea injection quantity required by the engine under the current working condition; determining a first urea injection quantity of a first SCR mixer according to the total required urea injection quantity and the first urea distribution proportion; a second urea injection amount of the second SCR mixer is determined based on the total required urea injection amount and the second urea distribution ratio. According to the method, the first urea distribution proportion of the first SCR mixer and the second urea distribution proportion of the second SCR mixer in the double-SCR system are respectively determined through the first crystal boundary of the first SCR mixer and the second crystal boundary of the second SCR mixer, the first urea injection amount of the first SCR mixer is further determined according to the first urea distribution proportion and the required urea injection total amount, the second urea injection amount of the second SCR mixer is determined according to the second urea distribution proportion and the required urea injection total amount, and crystallization is avoided by reasonably utilizing the anti-crystallization capacity of the first SCR mixer and the anti-crystallization capacity of the second SCR mixer in the double-SCR system.

In the practical use process of the urea nozzle of the SCR mixer, if the urea injection amount of the urea nozzle is too small, crystallization of the urea nozzle is likely to occur, and if the urea injection amount is too small, the calculation of the urea injection amount of the urea nozzle by the existing measuring instrument is likely to be inaccurate, so the embodiment of the disclosure can set the minimum urea injection amount for each urea nozzle in the dual SCR system to avoid the aforementioned problems.

Optionally, in the embodiment of the present disclosure, under the condition that the first urea injection amount is smaller than the minimum preset injection amount and the second urea injection amount is not smaller than the minimum preset injection amount, the first urea nozzle of the first SCR mixer is controlled to stop injecting urea, and the second SCR mixer is controlled to inject urea through the second urea nozzle according to the total required urea injection amount.

Optionally, in the embodiment of the present disclosure, under the condition that the first urea injection amount is not less than the minimum preset injection amount and the second urea injection amount is less than the minimum preset injection amount, the first SCR mixer may be controlled to inject urea through the first urea nozzle according to the total required urea injection amount, and the second urea nozzle of the second SCR mixer may be controlled to stop injecting urea.

Optionally, based on the method shown in fig. 1, as shown in fig. 5, a schematic diagram of another implementation manner of the urea injection quantity control method provided in the embodiment of the present disclosure may further include:

and S01, under the condition that the first urea injection quantity and the second urea injection quantity are not smaller than the first preset injection quantity, controlling the first SCR mixer to inject urea through the first urea nozzle according to the first urea injection quantity, and controlling the second SCR mixer to inject urea through the second urea nozzle according to the second urea injection quantity.

It is to be understood that the first preset injection amount may be a set minimum urea injection amount, and the minimum urea injection amount may be determined in conjunction with actual conditions. Alternatively, embodiments of the present disclosure may determine through experimentation the amount of urea injected by the urea injector that produces the critical point for crystallization. In a normal case, the minimum urea injection amount is set to be equal to or more than the urea injection amount at which the crystallization critical point occurs. According to the embodiment of the disclosure, under the condition that the first urea injection amount and the second urea injection amount are not less than the first preset injection amount, the SCR mixers are respectively controlled to inject urea according to the respective distributed urea injection amounts, the urea injection amounts of the SCR mixers in a double-SCR system are reasonably controlled, and the SCR mixer can be prevented from crystallizing due to overlarge urea injection amount of a single SCR mixer.

Alternatively, based on the method shown in fig. 1, as shown in fig. 6, another implementation of the urea injection quantity control method provided in the embodiment of the present disclosure is schematically illustrated, and in a case where the first urea nozzle is located upstream of the second urea nozzle, the urea injection quantity control method may further include:

and S02, controlling the first SCR mixer to inject urea through the first urea nozzle according to the total required urea injection amount and controlling the second urea nozzle of the second SCR mixer to stop injecting urea under the condition that the first urea injection amount and/or the second urea injection amount are/is smaller than a second preset injection amount.

It is understood that the second preset injection amount may be the set minimum urea injection amount. Therefore, the second preset injection amount may be equal to the first preset injection amount. According to the embodiment of the disclosure, under the condition that the first urea injection amount and/or the second urea injection amount are/is smaller than the second preset injection amount, the first urea injection nozzle which is positioned at the upstream of the second urea injection nozzle is controlled to inject urea, so that the evaporation time of urea can be prolonged, and the ammonia generation rate is improved.

FIG. 7 is a schematic diagram illustrating a control logic for controlling injection amount of dual urea nozzles in a dual SCR system according to an embodiment of the present disclosure.

It should be noted that while the present disclosure depicts the operations in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous.

It should be understood that the various steps recited in the method embodiments of the present disclosure may be performed in a different order, and/or performed in parallel. Moreover, method embodiments may include additional steps and/or omit performing the illustrated steps. The scope of the present disclosure is not limited in this respect.

In correspondence with the above method embodiment, the present disclosure also provides a urea injection amount control device, which is configured as shown in fig. 8, and is applied to a dual SCR system, the dual SCR system including a first SCR mixer and a second SCR mixer arranged in series, the first SCR mixer including a first urea nozzle, the second SCR mixer including a second urea nozzle, the urea injection amount control device including: an exhaust gas flow rate obtaining unit 100, an exhaust gas temperature obtaining unit 200, a first crystallization boundary determining unit 300, a second crystallization boundary determining unit 400, a urea distribution ratio determining unit 500, a required urea injection total amount obtaining unit 600, a first urea injection amount determining unit 700, and a second urea injection amount determining unit 800.

An exhaust flow rate obtaining unit 100 for obtaining an exhaust flow rate of the engine.

An exhaust gas temperature obtaining unit 200 for obtaining a first exhaust gas temperature upstream of the first urea nozzle and a second exhaust gas temperature upstream of the second urea nozzle.

A first crystallization boundary determining unit 300 for determining a first crystallization boundary of the first SCR mixer based on the exhaust gas flow rate and the first exhaust gas temperature.

Alternatively, the first crystal boundary determining unit 300 may include a third crystal boundary determining subunit and a first crystal boundary correcting subunit.

And the third crystallization boundary determining subunit is used for determining a third crystallization boundary in a first preset crystallization boundary MAP corresponding to the first SCR mixer according to the exhaust gas flow and the first exhaust gas temperature.

And the first crystallization boundary correction subunit is configured to perform curve correction on the third crystallization boundary according to the ambient temperature of the dual SCR system, so as to obtain a first crystallization boundary of the first SCR mixer.

A second crystal boundary determining unit 400 for determining a second crystal boundary of the second SCR mixer according to the exhaust gas flow rate and the second exhaust gas temperature.

Alternatively, the second crystal boundary determining unit 400 may include: the fourth crystal boundary determining subunit and the second crystal boundary correcting subunit.

A fourth crystal boundary determining subunit operable to determine a fourth crystal boundary in a second preset crystal boundary MAP corresponding to the second SCR mixer, according to the exhaust gas flow rate and the second exhaust gas temperature.

And the second crystal boundary correction subunit is used for performing curve correction on the fourth crystal boundary according to the ambient temperature of the dual-SCR system to obtain a second crystal boundary of the second SCR mixer.

A urea distribution ratio determining unit 500 for determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer based on the first crystal boundary and the second crystal boundary.

Alternatively, the urea distribution ratio determining unit 500 may include: the total crystallization value obtaining subunit, a first ratio determining subunit, and a second ratio determining subunit.

A total crystallization value obtaining subunit, configured to calculate a sum of the first crystallization boundary and the second crystallization boundary to obtain a total crystallization value.

A first proportion determining sub-unit for determining a ratio of the first crystal boundary to the total crystal value as a first urea distribution proportion of the first SCR mixer.

A second proportion determining subunit configured to determine a ratio of the second crystal boundary to the total crystal value as a second urea distribution proportion of the second SCR mixer.

And a total required urea injection amount obtaining unit 600 for obtaining a total required urea injection amount of the engine under the current operating condition.

A first urea injection amount determining unit 700 for determining a first urea injection amount of the first SCR mixer according to the total required urea injection amount and the first urea distribution ratio.

Optionally, the first urea injection amount determining unit 700 is specifically configured to determine a product of the total required urea injection amount and the first urea distribution ratio as the first urea injection amount of the first SCR mixer.

And a second urea injection amount determining unit 800 for determining a second urea injection amount of the second SCR mixer according to the total required urea injection amount and the second urea distribution ratio.

Optionally, the second urea injection amount determining unit 800 is specifically configured to determine a product of the total required urea injection amount and the second urea distribution ratio as the second urea injection amount of the second SCR mixer.

The urea injection amount control device is applied to a double SCR system, the double SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series, the first SCR mixer comprises a first urea nozzle, the second SCR mixer comprises a second urea nozzle, and the urea injection amount control method can obtain the exhaust flow input to the double SCR system; obtaining a first exhaust temperature upstream of the first urea nozzle and a second exhaust temperature upstream of the second urea nozzle; determining a first crystallization boundary of the first SCR mixer based on the exhaust flow rate and the first exhaust temperature; determining a second crystal boundary of a second SCR mixer based on the exhaust flow and the second exhaust temperature; determining a first urea distribution ratio of the first SCR mixer and a second urea distribution ratio of the second SCR mixer according to the first crystal boundary and the second crystal boundary; obtaining the total urea injection quantity required by the engine under the current working condition; determining a first urea injection quantity of a first SCR mixer according to the total required urea injection quantity and the first urea distribution proportion; a second urea injection amount of the second SCR mixer is determined based on the total required urea injection amount and the second urea distribution ratio. According to the method, the first urea distribution proportion of the first SCR mixer and the second urea distribution proportion of the second SCR mixer in the double-SCR system are respectively determined through the first crystal boundary of the first SCR mixer and the second crystal boundary of the second SCR mixer, the first urea injection amount of the first SCR mixer is further determined according to the first urea distribution proportion and the required urea injection total amount, the second urea injection amount of the second SCR mixer is determined according to the second urea distribution proportion and the required urea injection total amount, and crystallization is avoided by reasonably utilizing the anti-crystallization capacity of the first SCR mixer and the anti-crystallization capacity of the second SCR mixer in the double-SCR system.

Optionally, the urea injection amount control device may further include: a first urea injection control unit.

And the first urea injection control unit is used for controlling the first SCR mixer to inject urea through the first urea nozzle according to the first urea injection quantity and controlling the second SCR mixer to inject urea through the second urea nozzle according to the second urea injection quantity under the condition that the first urea injection quantity and the second urea injection quantity are not smaller than the first preset injection quantity.

Alternatively, the first urea injection nozzle may be located upstream of the second urea injection nozzle, and the urea injection amount control device may further include: a second urea injection control unit.

And the second urea injection control unit is used for controlling the first SCR mixer to inject urea through the first urea nozzle according to the total required urea injection amount and controlling the second urea nozzle of the second SCR mixer to stop injecting urea under the condition that the first urea injection amount and/or the second urea injection amount are/is smaller than a second preset injection amount.

With regard to the apparatus in the above-described embodiment, the specific manner in which each unit performs the operation has been described in detail in the embodiment related to the method, and will not be described in detail here.

The urea injection quantity control device comprises a processor and a memory, wherein the exhaust gas flow quantity obtaining unit 100, the exhaust gas temperature obtaining unit 200, the first crystallization boundary determining unit 300, the second crystallization boundary determining unit 400, the urea distribution ratio determining unit 500, the required urea injection total quantity obtaining unit 600, the first urea injection quantity determining unit 700, the second urea injection quantity determining unit 800 and the like are stored in the memory as program units, and the processor executes the program units stored in the memory to realize corresponding functions.

The processor comprises a kernel, and the kernel calls the corresponding program unit from the memory. The inner core can be set to be one or more, the inner core parameters are adjusted to respectively determine a first urea distribution proportion of the first SCR mixer and a second urea distribution proportion of the second SCR mixer through a first crystallization boundary of the first SCR mixer and a second crystallization boundary of the second SCR mixer in the double SCR system, further, a first urea injection amount of the first SCR mixer is determined according to the first urea distribution proportion and the required urea injection total amount, a second urea injection amount of the second SCR mixer is determined according to the second urea distribution proportion and the required urea injection total amount, and crystallization is avoided by reasonably utilizing the anti-crystallization capacity of the first SCR mixer and the anti-crystallization capacity of the second SCR mixer in the double SCR system.

The disclosed embodiments provide a computer-readable storage medium having stored thereon a program that, when executed by a processor, implements the urea injection amount control method.

The disclosed embodiment provides a processor for running a program, wherein the program runs to execute the urea injection amount control method.

The embodiment of the disclosure provides an electronic device, which comprises at least one processor, at least one memory connected with the processor, and a bus; the processor and the memory complete mutual communication through a bus; the processor is used for calling program instructions in the memory so as to execute the urea injection quantity control method. The electronic device herein may be a server, a PC, a PAD, a mobile phone, etc.

The present disclosure also provides a computer program product adapted to execute, when executed on an electronic device, a program initialized with the above-described urea injection quantity control method steps.

The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus, electronic devices (systems), and computer program products according to embodiments of the disclosure. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, an electronic device includes one or more processors (CPUs), memory, and a bus. The electronic device may also include input/output interfaces, network interfaces, and the like.

The memory may include volatile memory in a computer readable medium, Random Access Memory (RAM) and/or nonvolatile memory such as Read Only Memory (ROM) or flash memory (flash RAM), and the memory includes at least one memory chip. The memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

In the description of the present disclosure, it is to be understood that the directions or positional relationships as referred to by the terms "upper", "lower", "front", "rear", "left" and "right" and the like are merely for convenience of description and simplification of the description, and do not indicate or imply that the positions or elements referred to must have a specific direction, be constituted in a specific direction and operated, and thus, are not to be construed as limitations of the present disclosure.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

As will be appreciated by one skilled in the art, embodiments of the present disclosure may be provided as a method, system, or computer program product. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present disclosure may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and so forth) having computer-usable program code embodied therein.

The above are merely examples of the present disclosure, and are not intended to limit the present disclosure. Various modifications and variations of this disclosure will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the scope of the claims of the present disclosure.

Claims

1. A urea injection quantity control method is applied to a double SCR system, the double SCR system comprises a first SCR mixer and a second SCR mixer which are arranged in series, the first SCR mixer comprises a first urea nozzle, the second SCR mixer comprises a second urea nozzle, and the urea injection quantity control method comprises the following steps:

obtaining an exhaust flow rate of the engine;

2. The method of claim 1, further comprising:

3. The method of claim 1, wherein the first urea nozzle is located upstream of the second urea nozzle, the method further comprising:

4. The method of claim 1, wherein said determining a first crystallization boundary of the first SCR mixer based on the exhaust flow and the first exhaust temperature comprises:

5. The method of claim 1, wherein said determining a first urea split ratio for the first SCR mixer and a second urea split ratio for the second SCR mixer based on the first crystal boundary and the second crystal boundary comprises:

6. The method of claim 1, wherein said determining a first urea injection amount for the first SCR mixer based on the total requested urea injection amount and the first urea split ratio comprises:

7. A urea injection amount control device applied to a dual SCR system including a first SCR mixer and a second SCR mixer arranged in series, the first SCR mixer including a first urea injection nozzle, the second SCR mixer including a second urea injection nozzle, the urea injection amount control device comprising: an exhaust gas flow rate obtaining unit, an exhaust gas temperature obtaining unit, a first crystallization boundary determining unit, a second crystallization boundary determining unit, a urea distribution ratio determining unit, a required urea injection total amount obtaining unit, a first urea injection amount determining unit, and a second urea injection amount determining unit,

8. The apparatus of claim 7, further comprising: a first urea injection control unit for controlling the injection of urea,

9. A computer-readable storage medium on which a program is stored, the program implementing the urea injection quantity control method according to any one of claims 1 to 6 when executed by a processor.

10. An electronic device comprising at least one processor, and at least one memory connected to the processor, a bus; the processor and the memory complete mutual communication through the bus; the processor is configured to invoke program instructions in the memory to perform the urea injection quantity control method of any of claims 1-6.