Engine exhaust treatment control method, control device, and system

Abstract

The application discloses an engine tail gas treatment control method, a control device and a system, and belongs to the technical field of tail gas treatment. The engine tail gas treatment control method, the control device and the system of the application are characterized in that, according to the characteristics that PNA can adsorb NO x at low temperature and desorb NO x after temperature rising and the characteristics that SCR can efficiently react NO x at high temperature, the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency are taken as reference conditions, the operation mode of the engine is controlled, the original exhaust NO x amount and the exhaust temperature generated during the cold start of the engine are controlled, the purpose of improving the synergistic effect of PNA and SCR is achieved, PNA and SCR work in an optimal scheme and process NO x , and the engine meets the emission requirements.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas treatment technology, and in particular to engine exhaust gas treatment control methods, control devices and systems. Background Technology

[0002] With NO x With increasingly stringent emission requirements, NO2 during engine cold start is being increased. x Emission control faces significant challenges. Adding a PNA (Polymerized Atmosphere) to the existing aftertreatment systems of China VI emission standard products (such as China VI diesel engines) is necessary to address low-temperature NO emissions. x Emissions are one of the technical issues, as the main function of PNA is to adsorb NO during the cold start phase. x And after the temperature rises, the adsorbed NO will x Therefore, PNA needs to be coordinated with SCR to control emissions.

[0003] The role of SCR (Selective Catalytic Reduction) is to inject reducing agents into the exhaust gas and, under the action of a catalyst, reduce NO in the exhaust gas. x It is selectively reduced to non-toxic and harmless N2 and H2O.

[0004] PNA (Passive NO) x Adsorbent, passive NO x The role of adsorption technology is to be placed before SCR to adsorb NO during the cold start phase when the temperature is relatively low. x When the exhaust temperature rises, the adsorbed NO will be... x Detach out.

[0005] PNA primarily operates in the low-temperature range, specifically during engine cold starts, where it adsorbs NO. x NO is released after the exhaust temperature rises. x , make NO x It enters the SCR to react. Therefore, if PNA reacts with NO... x If urea is released too early or too much at once, before the SCR reaches its efficient reaction temperature range, the ammonia-to-nitrogen ratio is insufficient, or urea has not yet been injected, then PNA will not actually function, which can easily lead to NO buildup during the engine's cold start phase. x Emissions exceeded standards. Summary of the Invention

[0006] The purpose of this invention is to provide an engine exhaust gas treatment control method, control device and system, which improves the synergistic effect of PNA and SCR and ensures that the engine meets emission requirements.

[0007] To achieve the above objectives, the following technical solution is provided:

[0008] The first aspect is the engine exhaust gas treatment and control method, which includes the following steps:

[0009] When the engine is started and the engine is in a cold start condition, the exhaust of the engine is processed by an after-treatment system, which includes an SCR and a PNA located upstream of the SCR.

[0010] To obtain PNA storage capacity, PNA adsorption efficiency, and SCR reaction efficiency;

[0011] The PNA storage capacity and PNA storage threshold, the PNA adsorption efficiency and PNA efficiency threshold, and the SCR reaction efficiency and SCR efficiency threshold are compared respectively.

[0012] Based on the comparison results, the operating mode of the engine is determined, and the engine is controlled to operate in the determined mode.

[0013] As an alternative to the engine exhaust gas treatment control method, the process of determining the engine's operating mode based on the comparison results and controlling the engine to operate in the determined mode includes the following steps:

[0014] If the PNA storage amount is not greater than the PNA storage threshold, and the PNA adsorption efficiency is not less than the PNA efficiency threshold, then the engine is operated in a first mode. When the engine is operated in the first mode, the original NO emissions are... x The amount is less than the original NO produced when the engine is running in normal mode. x The exhaust temperature of the engine when it is running in the first mode is higher than the exhaust temperature of the engine when it is running in the normal mode.

[0015] If the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is not greater than the SCR efficiency threshold, then the engine is operated in a second mode. When the engine is operated in the second mode, the original NO emissions are... x The amount is less than the original NO produced when the engine is running in normal mode. x quantity;

[0016] If the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is greater than the SCR efficiency threshold, then the engine is operated in the third mode, and the exhaust temperature of the engine in the third mode is higher than the exhaust temperature of the engine in the normal mode.

[0017] As an alternative to the engine exhaust treatment control method, the first mode is a high heating and low emission mode;

[0018] The second mode is a low emission mode;

[0019] The third mode is a high heating mode.

[0020] As an alternative to the engine exhaust treatment control method, after the step of operating the engine to a first mode, the first mode being a high heating and low emission mode, further comprising the steps of:

[0021] When the SCR temperature reaches a preset temperature, the engine is caused to exit the high heating mode;

[0022] When the SCR reaction efficiency reaches the SCR efficiency threshold or the engine operating time in the low emission mode reaches a preset time, the engine is caused to exit the low emission mode;

[0023] After the step of operating the engine to a second mode, the second mode being a low emission mode, further comprising the steps of:

[0024] When the SCR reaction efficiency reaches the SCR efficiency threshold or the engine operating time in the low emission mode reaches a preset time, the engine is caused to exit the low emission mode;

[0025] After the step of operating the engine to a third mode, the third mode being a high heating mode, further comprising the steps of:

[0026] When the SCR temperature reaches a preset temperature, the engine is caused to exit the high heating mode;

[0027] As an alternative to the engine exhaust treatment control method, in the step of controlling the engine to operate in the determined mode, further comprising the steps of:

[0028] Adjusting the combustion parameters of the engine and / or actuator actions to cause the engine to operate in the determined mode.

[0029] As an alternative to the engine exhaust treatment control method, the combustion parameters include rail pressure, advance angle, and fuel injection amount;

[0030] The actuator actions include intake valve opening and exhaust valve opening.

[0031] As an alternative to the engine exhaust treatment control method, in the steps of obtaining PNA storage amount, PNA adsorption efficiency, and SCR reaction efficiency, further comprising the steps of:

[0032] According to the PNA temperature, the PNA space velocity and the engine raw exhaust NO x amount, the PNA storage amount is obtained.

[0033] In the obtaining of the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency, the following step is further included:

[0034] According to the PNA temperature, the PNA space velocity and the engine raw exhaust NO x amount, the PNA adsorption efficiency is obtained.

[0035] As an alternative of the engine exhaust treatment control method, the SCR reaction efficiency is equal to the ratio of the difference between the tail exhaust NO x amount and the raw exhaust NO x amount and the raw exhaust NO x amount.

[0036] In a second aspect, an engine exhaust treatment control device is provided, comprising:

[0037] A data acquisition module, which is capable of acquiring the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency;

[0038] A data processing module, which is capable of comparing the PNA storage amount with a PNA storage threshold value, the PNA adsorption efficiency with a PNA efficiency threshold value and the SCR reaction efficiency with a SCR efficiency threshold value according to the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency obtained by the data acquisition module respectively;

[0039] A control module, which is capable of determining the operation mode of the engine and controlling the engine to operate in the determined mode according to the comparison results of the data processing module.

[0040] In a third aspect, an engine exhaust treatment system is provided, comprising an aftertreatment device and an engine exhaust treatment control device as described above, the aftertreatment device is used for treating the exhaust gas of the engine, the aftertreatment device comprises an SCR and a PNA located upstream of the SCR, and the engine exhaust treatment control device is communicatively connected with the aftertreatment device and the engine respectively.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] The engine exhaust treatment control method, control device and system of the present application are based on the characteristics of the PNA in adsorbing NO x at low temperature and desorbing NO x after warming up and the high-efficiency reaction of the SCR to NO xcharacteristics, taking the PNA storage amount, PNA adsorption efficiency and SCR reaction efficiency as reference conditions, controlling the operation mode of the engine, and then controlling the original exhaust NO x amount and exhaust temperature generated by the engine during cold start, so as to improve the synergistic effect of PNA and SCR, and make PNA and SCR work in an optimal scheme and treat NO x BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The flow chart of the engine exhaust treatment control method in the embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be described clearly and completely below in combination with the drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiment of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0046] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0047] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation, and cannot be understood as indicating or implying relative importance. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0048] ​In the description of the present application, it is also necessary to explain that, unless otherwise explicitly specified and limited, the terms "arrangement", "connection" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0049] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include 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 through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "lower", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0050] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0051] As Figure 1 shown, the present embodiment provides an engine exhaust treatment control method, comprising the following steps:

[0052] S1, starting the engine and the engine being in a cold start condition, treating the exhaust gas of the engine by a post-treatment device, the post-treatment device comprising an SCR and a PNA located upstream of the SCR;

[0053] The realization of the adsorption and desorption functions of the PNA needs to meet a certain temperature range, and the main working temperature range of the PNA is low, and the temperature range of the SCR reaction is high, so the cooperative control of the PNA and the SCR usually only occurs when the engine is started and is in a cold start condition.

[0054] S2, obtaining the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency;

[0055] It should be noted that the PNA temperature, the PNA space velocity and the engine raw NOx x amount will all affect the PNA storage amount and the PNA adsorption efficiency. In the present embodiment, according to the PNA temperature, the PNA space velocity and the engine raw NOx xThe amount of PNA stored and the adsorption efficiency were obtained. It should be noted that the PNA storage capacity and adsorption efficiency were determined based on the PNA temperature, PNA space velocity, and the original NO emissions from the engine. x The specific methods and steps for estimating PNA storage capacity and PNA adsorption efficiency are existing technologies in this field and will not be elaborated here.

[0056] Furthermore, SCR temperature, SCR space velocity, urea injection rate, and NO desorption from PNA... x The amount of each component affects the SCR reaction efficiency; however, the SCR reaction efficiency is ultimately reflected in the SCR's effect on NO in the engine's original exhaust. x In this embodiment, the SCR reaction efficiency is equal to the original NO discharge capacity. x Volume and tail NO x The difference in quantity and the original NO x The ratio of quantities.

[0057] Understandably, in practical applications, the after-processor airspeed is usually used as the PNA airspeed and SCR airspeed, and the after-processor airspeed is the length of time the exhaust gas stays in the after-processor.

[0058] S3. Compare the PNA storage capacity with the PNA storage threshold, the PNA adsorption efficiency with the PNA efficiency threshold, and the SCR reaction efficiency with the SCR efficiency threshold, respectively.

[0059] PNA storage capacity, i.e., the amount of NO that a PNA can store. x The maximum capacity is limited because PNA desorbs rapidly above a certain temperature, limiting the storage of NO. x The amount of PNA affects the SCR reaction during desorption, therefore the amount of PNA stored is used as one of the reference conditions for controlling the synergistic operation of PNA and SCR.

[0060] PNA adsorption efficiency refers to the effect of PNA on NO in the engine exhaust. x The adsorption capacity of PNA is high; a high adsorption efficiency indicates that PNA can effectively adsorb NO. x It has a strong adsorption capacity and can quickly adsorb NO emitted from the source. x Low PNA adsorption efficiency indicates that PNA has poor adsorption capacity for NO. x Its adsorption capacity is weak, and it is not effective against NO emissions. x The adsorption rate of PNA for NO is relatively low. x The adsorption efficiency of NO also affects x The amount of desorption affects the SCR reaction, so the adsorption efficiency of PNA is also used as one of the reference conditions for controlling the synergistic effect of PNA and SCR.

[0061] SCR reaction efficiency, i.e., the effect of SCR on NO. x The processing capacity of SCR is high; a high SCR reaction efficiency indicates that SCR can effectively process NO. xThe PNA has high processing capacity and can quickly convert NO x into non-toxic and harmless N2 and H2O. Low SCR reaction efficiency means that the SCR has low efficiency in converting NO x into non-toxic and harmless N2 and H2O. x Therefore, the SCR reaction efficiency will affect the engine cold start emission level, and thus the SCR reaction efficiency is also one of the reference conditions for controlling the cooperation of the PNA and the SCR.

[0062] It should be noted that the PNA storage threshold, the PNA efficiency threshold and the SCR efficiency threshold can be determined according to the model or parameters of the engine, the PNA and the SCR, and test data or design experience, and are not limited herein.

[0063] S4, determining the operation mode of the engine according to the comparison result, and controlling the engine to operate in the determined mode.

[0064] In this embodiment, step S4 includes the following steps.

[0065] S41, if the PNA storage amount is not greater than the PNA storage threshold and the PNA adsorption efficiency is not less than the PNA efficiency threshold, the engine is controlled to operate in the first mode, and the original exhaust NOx amount generated when the engine operates in the first mode is less than the original exhaust NOx amount generated when the engine operates in the normal mode, and the exhaust gas temperature when the engine operates in the first mode is higher than the exhaust gas temperature when the engine operates in the normal mode. x x

[0066] When the PNA storage amount is not greater than the PNA storage threshold and the PNA adsorption efficiency is not less than the PNA efficiency threshold, the PNA storage amount is small at this time, the PNA has high adsorption speed for the original exhaust NOx, and the PNA is easily saturated, so it is necessary to quickly pass through the cold start process and make the PNA adsorb as little NOx as possible. x x Therefore, the engine is controlled to reduce the original exhaust NOx amount generated by the engine, so that the PNA adsorbs and releases less NOx, thereby reducing the pressure of the SCR; and the exhaust gas temperature of the engine is increased, so that the exhaust gas temperature of the engine can quickly promote the SCR to enter the SCR high-efficiency reaction temperature range. When the SCR temperature is in the SCR high-efficiency reaction temperature range, the SCR reaction efficiency is high, and NO x can be quickly converted into non-toxic and harmless N2 and H2O. x x

[0067] ​​​​​In this embodiment, the first mode is a high heating and low raw emission mode (i.e., high heating mode + low raw emission mode). It should be noted that the high heating mode and the low raw emission mode are both preset modes of the engine. When the engine is running in the high heating mode, the exhaust temperature of the engine is increased, thereby quickly promoting the SCR to enter the SCR high-efficiency reaction temperature range. When the engine is running in the low raw emission mode, the raw emission NOx generated by the engine is reduced. In this way, the running mode of the engine can be quickly changed, and it is ensured that the emission meets the requirements. x

[0068] In this embodiment, the running mode of the engine can be changed by adjusting the combustion parameters of the engine and / or the actuator action, so as to make the engine run in the first mode. The combustion parameters include rail pressure, advance angle and fuel injection amount. The actuator action includes intake valve opening degree and exhaust valve opening degree.

[0069] For example, by reducing the rail pressure, delaying the advance angle, and increasing the fuel injection amount, the engine can run in the high heating mode, and the exhaust temperature of the engine is increased. Of course, the engine can also be starved by reducing the intake valve opening degree and reducing the exhaust valve opening degree, so as to achieve the purpose of increasing the exhaust temperature of the engine.

[0070] For example, by reducing the rail pressure and delaying the advance angle, the engine can run in the low raw emission mode, so as to reduce the raw emission NOx generated by the engine. x

[0071] Of course, in other embodiments, the rail pressure, the advance angle, the fuel injection amount, the intake valve opening degree and the exhaust valve opening degree can also be coupled in other ways to control the running mode of the engine. By changing the rail pressure, the advance angle, the fuel injection amount, the intake valve opening degree and the exhaust valve opening degree to control the running mode of the engine is the prior art in the art, which will not be described here.

[0072] It should be noted that the engine running in the normal mode means that the engine is not subjected to thermal management, and the engine maintains normal raw emission.

[0073] After the engine runs in the high heating mode + low raw emission mode, the following steps are further included:

[0074] When the SCR temperature reaches the preset temperature, the engine exits the high heating mode;

[0075] When the SCR reaction efficiency reaches the SCR efficiency threshold or the engine runs in the low raw emission mode for a preset duration, the engine exits the low raw emission mode.

[0076] ​​In other words, when the PNA storage amount is not greater than the PNA storage threshold value and the PNA adsorption efficiency is not less than the PNA efficiency threshold value, the engine is caused to run to the forced heating mode + the low original emission mode, until the SCR temperature reaches the preset temperature, and then the engine is caused to exit the forced heating mode; until the SCR reaction efficiency reaches the SCR efficiency threshold value or the running time length of the engine in the low original emission mode reaches the preset time length, the engine is caused to exit the low original emission mode.

[0077] It should be noted that, during the engine cold start stage, the SCR reaction efficiency is low, and as the running time length of the engine increases, the engine exhaust can heat up the SCR, thereby gradually improving the SCR reaction efficiency, and therefore, when the running time length of the engine in the low original emission mode reaches the preset time length, the SCR reaction efficiency can also be greatly improved.

[0078] Further, in step S41, the exhaust temperature of the engine is increased to quickly promote the SCR to enter the SCR high-efficiency reaction temperature range, and therefore, in the present embodiment, the preset temperature is an interval value, and specifically, the preset temperature is the SCR high-efficiency reaction temperature range.

[0079] It should be noted that, if the condition for exiting the forced heating mode is met first, the engine is caused to exit the forced heating mode first, and if the condition for exiting the low original emission mode is not met at this time, the engine is caused to continue running in the low original emission mode, until the condition for exiting the low original emission mode is met, and then the engine is caused to exit the low original emission mode, at which time the engine returns to the normal mode. Similarly, if the condition for exiting the low original emission mode is met first, the engine is caused to exit the low original emission mode first, and if the condition for exiting the forced heating mode is not met at this time, the engine is caused to continue running in the forced heating mode, until the condition for exiting the forced heating mode is met, and then the engine is caused to exit the forced heating mode, at which time the engine returns to the normal mode.

[0080] Further, for ease of description, the SCR reaction efficiency reaching the SCR efficiency threshold value is recorded as the first condition for exiting the low original emission mode, and the running time length of the engine in the low original emission mode reaching the preset time length is recorded as the second condition for exiting the low original emission mode. In the present embodiment, when one of the first condition and the second condition is met, the engine is caused to exit the low original emission mode, in other words, regardless of which of the first condition and the second condition is met first, as long as one of the conditions is met, the engine is caused to exit the low original emission mode.

[0081] S42, if the PNA storage amount is greater than the PNA storage threshold value or the PNA adsorption efficiency is less than the PNA efficiency threshold value, and the SCR reaction efficiency is not greater than the SCR efficiency threshold value, the engine is caused to run to the second mode, and the original emission NOx generated when the engine runs to the second mode is less than the original emission NOx generated when the engine runs to the normal mode. x x ​quantity;

[0082] When the PNA storage level exceeds the PNA storage threshold and the SCR reaction efficiency does not exceed the SCR efficiency threshold, the PNA storage level is high and the SCR reaction efficiency is low. Therefore, the risk of engine emissions exceeding standards is high, and engine control is needed to reduce the NO emissions generated by the engine. x The quantity decreased.

[0083] When the PNA adsorption efficiency is less than the PNA efficiency threshold and the SCR reaction efficiency is not greater than the SCR efficiency threshold, then the PNA adsorption efficiency for the original NO emissions is significantly reduced. x The adsorption rate of NO is relatively low, and the SCR reaction efficiency is also low. Therefore, the risk of engine emissions exceeding standards is also high, and engine control is necessary to reduce the amount of NO produced by the engine. x The quantity decreased.

[0084] In this embodiment, the second mode is the low-exhaust mode. By adjusting the engine's combustion parameters, the engine's operating mode can be changed to make the engine operate in the second mode; the combustion parameters include rail pressure, advance angle, and fuel injection quantity; the actuator actions include the intake valve opening degree and the exhaust valve opening degree.

[0085] For example, by reducing the rail pressure and delaying the advance angle, the engine can be operated in a low primary exhaust mode, thereby reducing the primary exhaust NO produced by the engine. x The quantity decreased.

[0086] Of course, in other embodiments, rail pressure, advance angle, and fuel injection quantity can be coupled in other ways to control the engine's operating mode. Controlling the engine's operating mode by changing rail pressure, advance angle, and fuel injection quantity is prior art and will not be elaborated upon here.

[0087] After setting the engine to low exhaust mode, the following steps are also included:

[0088] When the SCR reaction efficiency reaches the SCR efficiency threshold or the engine runs for a preset duration in low exhaust mode, the engine exits the low exhaust mode.

[0089] In other words, when the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is not greater than the SCR efficiency threshold, the engine will run in low exhaust mode until the SCR reaction efficiency reaches the SCR efficiency threshold or the engine runs in low exhaust mode for a preset duration, at which point the engine will exit low exhaust mode. That is to say, the engine will then return to normal mode.

[0090] Understandably, regardless of whether the first or second condition for exiting low exhaust mode is met first, as long as one of the conditions is met, the engine can exit low exhaust mode.

[0091] S43. If the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is greater than the SCR efficiency threshold, then the engine is set to the third mode. The exhaust temperature of the engine in the third mode is higher than the exhaust temperature of the engine in the normal mode.

[0092] When the PNA storage capacity exceeds the PNA storage threshold and the SCR reaction efficiency exceeds the SCR efficiency threshold, the PNA storage capacity is large. In other words, during PNA desorption, the released NO... x The amount is also relatively large, requiring SCR to be able to handle the large amount of NO released by PNA. x The reaction occurs, so the engine is controlled to raise the exhaust temperature, thereby allowing the SCR to enter its efficient reaction temperature range as quickly as possible.

[0093] When the PNA adsorption efficiency is less than the PNA efficiency threshold and the SCR reaction efficiency is greater than the SCR efficiency threshold, the PNA adsorption efficiency is low, and it is necessary to avoid PNA being in a state of adsorbing NO for a long time. x The temperature range is such that the engine is controlled to increase the exhaust temperature, thereby shortening the time that PNA is in the NO adsorption range. x The duration of the temperature range, and to enable SCR to enter the efficient reaction temperature range as soon as possible.

[0094] In this embodiment, the third mode is a strong heating mode. The engine's operating mode can be changed by adjusting the engine's combustion parameters and / or actuator actions to bring the engine to the third mode. Combustion parameters include rail pressure, advance angle, and fuel injection quantity; actuator actions include intake valve opening and exhaust valve opening.

[0095] For example, by reducing rail pressure, delaying engine advance angle, and increasing fuel injection quantity, the engine can be operated in a strong heating mode, thereby increasing the engine exhaust temperature. Alternatively, by reducing the intake valve opening and the exhaust valve opening, the engine can be forced to hold its breath, which also increases the engine exhaust temperature.

[0096] Of course, in other embodiments, rail pressure, advance angle, fuel injection quantity, intake valve opening, and exhaust valve opening can be coupled in other ways to control the engine's operating mode. Controlling the engine's operating mode by changing rail pressure, advance angle, fuel injection quantity, intake valve opening, and exhaust valve opening is prior art and will not be elaborated further here.

[0097] After setting the engine to high heating mode, the following steps are also included:

[0098] When the SCR temperature reaches the preset temperature, the engine is caused to exit the forced heating mode.

[0099] In other words, when the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is greater than the SCR efficiency threshold, the engine is caused to run to the forced heating mode until the SCR temperature reaches the preset temperature, and then the engine is caused to exit the forced heating mode. That is, the engine is restored to the normal mode at this time.

[0100] It can be understood that in step S43, the exhaust temperature of the engine is increased to quickly promote the SCR to enter the SCR high-efficiency reaction temperature range, and therefore, in the present embodiment, the preset temperature is an interval value, specifically, the preset temperature is the SCR high-efficiency reaction temperature range. When the SCR temperature is in the SCR high-efficiency reaction temperature range, the SCR reaction efficiency is relatively high, and NOx in the exhaust gas can be quickly reduced to N2 and H2O. x

[0101] S44, in addition to the cases described in steps S41, S42 and S43, the engine is caused to run in the normal mode.

[0102] The engine exhaust treatment control method, control device and system of the present embodiment, according to the characteristics of PNA adsorbing NOx at low temperature and desorbing NOx after warming up, and the characteristics of SCR being able to efficiently react NOx at high temperature, take the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency as reference conditions, control the running mode of the engine, and further control the original exhaust NOx amount and the exhaust temperature generated during cold start of the engine, in order to achieve the purpose of improving the synergistic effect of PNA and SCR, so that PNA and SCR work synergistically in the optimal scheme and process NOx, to ensure that the engine meets the emission requirements. x x x x x

[0103] The present embodiment also provides an engine exhaust treatment control device for implementing the engine exhaust treatment control method as described above, and the engine exhaust treatment control device comprises a data acquisition module, a data processing module and a control module.

[0104] The data acquisition module can acquire the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency;

[0105] ​​​​​​The data processing module is in communication connection with the data acquisition module, and the data processing module can compare the PNA storage amount, the PNA adsorption efficiency and the SCR reaction efficiency obtained by the data acquisition module with the PNA storage threshold value, the PNA efficiency threshold value and the SCR efficiency threshold value, respectively.

[0106] The control module is in communication connection with the data processing module, and the control module can determine the operation mode of the engine according to the comparison result of the data processing module, and control the engine to operate in the determined mode.

[0107] The engine exhaust treatment control device of the embodiment has the same beneficial effects as the engine exhaust treatment control method.

[0108] The embodiment further provides an engine exhaust treatment system, which comprises an aftertreatment device and the engine exhaust treatment control device as described above, the aftertreatment device is used for treating the exhaust of the engine, the aftertreatment device comprises an SCR and a PNA located upstream of the SCR, and the engine exhaust treatment control device is in communication connection with the aftertreatment device and the engine. The engine exhaust treatment system of the embodiment has the same beneficial effects as the engine exhaust treatment control method by applying the engine exhaust treatment control device adopting the engine exhaust treatment control method.

[0109] Note that the above are only the preferred embodiments of the present application and the applied technical principles. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the appended claims.

Claims

1. An engine exhaust gas treatment and control method, characterized in that, Includes the following steps: When the engine is started and the engine is in a cold start condition, the exhaust of the engine is processed by an after-treatment system, which includes an SCR and a PNA located upstream of the SCR. To obtain PNA storage capacity, PNA adsorption efficiency, and SCR reaction efficiency; The PNA storage capacity and PNA storage threshold, the PNA adsorption efficiency and PNA efficiency threshold, and the SCR reaction efficiency and SCR efficiency threshold are compared respectively. Based on the comparison results, the operating mode of the engine is determined, and the engine is controlled to operate in the determined mode, including the following steps: If the PNA storage amount is not greater than the PNA storage threshold, and the PNA adsorption efficiency is not less than the PNA efficiency threshold, then the engine is operated in a first mode. When the engine is operated in the first mode, the original NO emissions are... x The amount is less than the original NO produced when the engine is running in normal mode. x The exhaust temperature of the engine when it is running in the first mode is higher than the exhaust temperature of the engine when it is running in the normal mode. If the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is not greater than the SCR efficiency threshold, then the engine is operated in a second mode. When the engine is operated in the second mode, the original NO emissions are... x The amount is less than the original NO produced when the engine is running in normal mode. x quantity; If the PNA storage amount is greater than the PNA storage threshold or the PNA adsorption efficiency is less than the PNA efficiency threshold, and the SCR reaction efficiency is greater than the SCR efficiency threshold, then the engine is operated in the third mode, and the exhaust temperature of the engine in the third mode is higher than the exhaust temperature of the engine in the normal mode.

2. The engine exhaust gas treatment and control method according to claim 1, characterized in that, The first mode is a strong heating and low exhaust mode; The second mode is the low-order original mode; The third mode is a strong heating mode.

3. The engine exhaust gas treatment and control method according to claim 2, characterized in that, After operating the engine in a first mode, which is a strong heating and low exhaust mode, the following steps are also included: When the SCR temperature reaches the preset temperature, the engine is deactivated from the strong heating mode. When the SCR reaction efficiency reaches the SCR efficiency threshold or the engine runs for a preset duration in the low exhaust mode, the engine exits the low exhaust mode. After the engine is operated to the second mode, which is a low exhaust mode, the following steps are also included: When the SCR reaction efficiency reaches the SCR efficiency threshold or the engine runs for a preset duration in the low exhaust mode, the engine exits the low exhaust mode. After the engine is operated to the third mode, which is a strong heating mode, the following steps are also included: When the SCR temperature reaches the preset temperature, the engine is deactivated from the strong heating mode.

4. The engine exhaust gas treatment and control method according to claim 1, characterized in that, Controlling the engine to operate in the determined mode includes the following steps: Adjust the combustion parameters and / or actuator actions of the engine to make the engine operate in a determined mode.

5. The engine exhaust gas treatment and control method according to claim 4, characterized in that, The combustion parameters include rail pressure, advance angle, and fuel injection quantity; The actuator actions include the opening of the intake valve and the opening of the exhaust valve.

6. The engine exhaust gas treatment and control method according to claim 1, characterized in that, The process of obtaining PNA storage capacity, PNA adsorption efficiency, and SCR reaction efficiency includes the following steps: Based on PNA temperature, PNA airspeed, and engine exhaust NO x Quantity, to obtain the storage amount of the PNA; Based on PNA temperature, PNA airspeed, and engine exhaust NO x The adsorption efficiency of the PNA was obtained by measuring the amount of PNA.

7. The engine exhaust gas treatment and control method according to claim 1, characterized in that, The SCR reaction efficiency is equal to the original NO emission efficiency. x Volume and tail NO x The difference in quantity and the original NO x The ratio of quantities.

8. An engine exhaust gas treatment control device, characterized in that, For performing the engine exhaust gas treatment control method as described in any one of claims 1-7, comprising: The data acquisition module is capable of acquiring PNA storage capacity, PNA adsorption efficiency, and SCR reaction efficiency. The data processing module is capable of comparing the PNA storage amount with the PNA storage threshold, the PNA adsorption efficiency with the PNA efficiency threshold, and the SCR reaction efficiency with the SCR efficiency threshold, respectively, based on the PNA storage amount, the PNA adsorption efficiency, and the SCR reaction efficiency obtained by the data acquisition module. The control module is capable of determining the engine's operating mode based on the comparison results from the data processing module, and controlling the engine to operate in the determined mode.

9. An engine exhaust gas treatment system, characterized in that, The system includes an after-processor and an engine exhaust gas treatment control device as described in claim 8, wherein the after-processor is used to treat engine exhaust gas, the after-processor includes an SCR and a PNA located upstream of the SCR, and the engine exhaust gas treatment control device is communicatively connected to the after-processor and the engine, respectively.

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