CN113417752B - Optimization control method and device and electronic equipment - Google Patents

Optimization control method and device and electronic equipment Download PDF

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CN113417752B
CN113417752B CN202110857180.5A CN202110857180A CN113417752B CN 113417752 B CN113417752 B CN 113417752B CN 202110857180 A CN202110857180 A CN 202110857180A CN 113417752 B CN113417752 B CN 113417752B
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engine
temperature
nox
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CN113417752A (en
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张军
秦涛
褚国良
闫立冰
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Weichai Power Co Ltd
Weifang Weichai Power Technology Co Ltd
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Weichai Power Co Ltd
Weifang Weichai Power Technology Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D43/00—Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Abstract

The invention discloses an optimization control method, an optimization control device and electronic equipment, wherein the method comprises the following steps: calculating the predicted values of the exhaust temperature of the engine and the primary NOx by using a preset formula with the lowest oil consumption as the target; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption; under the condition of meeting a preset condition, controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx; the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition. Therefore, the purpose of optimizing the oil consumption is achieved on the premise of guaranteeing the CO2 emission standard.

Description

Optimization control method and device and electronic equipment
Technical Field
The invention relates to the field of control, in particular to an optimization control method, an optimization control device and electronic equipment.
Background
Modern emission regulations require that ultra-low emissions be widely used in diesel powered systems, including commercial vehicles, heavy trucks and off-highway vehicle machinery, etc., and in order to ensure that the emission limits for CO2 prescribed by emission laws may be met, it is desirable to reduce NOx emissions as much as possible at the expense of fuel consumption, but this is highly undesirable to the user. Therefore, a method for reducing fuel consumption while ensuring that the emission range of CO2 specified by the emission law is reached is needed.
Disclosure of Invention
In view of this, the embodiment of the invention discloses an optimization control method and device, which achieve the purposes of ensuring that the emission range of CO2 specified by an emission law is met and reducing oil consumption.
The embodiment of the invention discloses an optimization control method, which comprises the following steps:
acquiring the current exhaust gas flow and DPF pressure difference;
calculating the predicted values of the exhaust temperature of the engine and the primary NOx by using a preset formula with the lowest oil consumption as the target; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption;
under the condition of meeting a preset condition, controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx;
the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition.
Optionally, the method further includes:
acquiring SCR actual efficiency and SCR model efficiency, and calculating basic efficiency deviation according to the SCR actual efficiency and the SCR model efficiency;
determining an interpolation factor corresponding to the basic efficiency deviation;
acquiring the current SCR temperature and flow, and determining at least one efficiency distribution factor MAP based on the current SCR temperature and flow; the efficiency distribution factor MAP is expressed as the ratio of different adjustment SCR efficiency deviation distributions;
interpolating at least one efficiency distribution factor by using the interpolation factor to obtain a target efficiency distribution factor MAP;
calculating an original computer efficiency deviation according to the basic efficiency deviation and a target efficiency distribution factor;
determining an upper limit value and a lower limit value of the original NOx corresponding to the current working condition based on the deviation of the actual efficiency and the original machine efficiency of the SCR and a preset first MAP; the first MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency, the upper limit value of the original NOx and the lower limit value of the original NOx;
determining a lower limit value of the SCR temperature based on the actual SCR efficiency, the original machine efficiency deviation and a preset second MAP; and the second MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency and the lower limit value of the SCR temperature.
Optionally, the preset condition further includes:
the current DPF pressure difference is less than or equal to a DPF pressure difference limit value preset under the current working condition;
the current DPF pressure difference is less than or equal to a preset DPF pressure difference limit value under the current working condition;
the PDF differential pressure limit is determined by the current exhaust gas flow and a preset exhaust gas flow versus DPF differential pressure limit.
Optionally, the controlling the engine through the engine exhaust temperature and the primary NOx includes:
determining a first engine parameter through the engine exhaust temperature and a preset third MAP; the preset third MAP represents the relation between the first engine parameter and the engine exhaust temperature; the first engine parameter is a parameter related to engine control of primary NOx;
acquiring the current actual engine exhaust temperature, and calculating the temperature deviation according to the current actual engine exhaust temperature and the predicted engine exhaust temperature;
determining a second engine parameter according to a preset relationship between the second engine parameter and the temperature deviation; the second engine parameter is a parameter related to controlling engine exhaust temperature;
controlling an engine based on the first and second engine parameters.
Optionally, the first engine parameter at least includes: advance angle, rail pressure, intake oxygen concentration and intake pressure.
Optionally, the second engine parameter comprises: post-injection oil quantity and intake pressure.
The embodiment of the invention discloses an optimization control device, which comprises:
the acquisition unit is used for acquiring the current exhaust gas flow and DPF pressure difference;
the prediction unit is used for calculating the prediction value of the exhaust temperature of the engine and the original NOx through a preset formula with the aim of lowest oil consumption; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption;
the optimization control unit is used for controlling the engine through the predicted values of the engine exhaust temperature and the primary NOx under the condition of meeting preset conditions;
the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition.
Optionally, the method further includes:
a limit determination unit to:
acquiring SCR actual efficiency and SCR model efficiency, and calculating basic efficiency deviation according to the SCR actual efficiency and the SCR model efficiency;
determining an interpolation factor corresponding to the basic efficiency deviation;
acquiring the current SCR temperature and flow, and determining at least one efficiency distribution factor MAP based on the current SCR temperature and flow; the efficiency distribution factor MAP is expressed as the ratio of different adjustment SCR efficiency deviation distributions;
interpolating at least one efficiency distribution factor by using the interpolation factor to obtain a target efficiency distribution factor MAP;
calculating an original computer efficiency deviation according to the basic efficiency deviation and a target efficiency distribution factor;
determining an upper limit value and a lower limit value of the corresponding primary NOx under the current working condition based on the deviation of the actual efficiency and the original machine efficiency of the SCR and a preset first MAP; the first MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency, the upper limit value of the original NOx and the lower limit value of the original NOx;
determining a lower limit value of the SCR temperature based on the actual SCR efficiency, the original machine efficiency deviation and a preset second MAP; and the second MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency and the lower limit value of the SCR temperature.
The embodiment of the invention discloses electronic equipment, which is characterized by comprising:
a memory and a processor;
the memory is used for storing programs, and the processor is used for executing the optimization control method when executing the programs stored in the memory.
The embodiment of the invention discloses an optimization control method, an optimization control device and electronic equipment, wherein the method comprises the following steps: calculating the predicted values of the exhaust temperature of the engine and the primary NOx by using a preset formula with the lowest oil consumption as the target; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption; under the condition of meeting a preset condition, controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx; the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition. Therefore, the purpose of optimizing the oil consumption is achieved on the premise of guaranteeing the CO2 emission standard.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a flow chart illustrating an emission method based on optimal control according to an embodiment of the present disclosure;
FIG. 2 illustrates a flow chart for determining current SCR temperature limits and upper and lower NOx emissions limits provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a post-processing model according to an embodiment of the present invention;
FIG. 4 illustrates an optimized control process for an integrated control model;
FIG. 5 is a schematic structural diagram of an optimization control device according to an embodiment of the present invention;
fig. 6 shows a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The noun explains:
currently, for the treatment of diesel exhaust, the commonly used technologies include: DOC (oxidation Catalytic reaction), DPF (Particulate matter trapping technology), SCR (Selective Catalytic Reduction technology).
Example 1
Referring to fig. 1, a flow chart of an emission method based on optimization control disclosed by an embodiment of the invention is shown, and in the embodiment, the method comprises the following steps:
s101: acquiring the current exhaust gas flow and DPF pressure difference;
in this embodiment, a DPF differential pressure sensor is provided in advance for detecting the current DPF differential pressure.
Wherein the exhaust gas flow is calculated by a pre-constructed engine prototype model.
In this embodiment, an original engine model of the engine is pre-constructed, and the original engine model of the engine has a capability of simulating an operation process of the engine in a normal state, wherein the engine model may be constructed in various ways, for example, the original engine model of the engine may adopt a physical model based on a principle, wherein the original engine model of the engine includes: a gas flow model, a NOx generation model, and an exhaust temperature model.
Wherein the gas flow model is modeled based on a gas flow formula using valves such as an EGR valve, a supercharger, an intake throttle valve, etc., as shown in the following formula 1, wherein in the formula 1, M f Denotes the gas flow rate, f (P) 2 /P 1 ) Representing outlet gas pressure versus inlet gas pressure, area represents the maximum cross-sectional flow Area and g (u) represents a function of valve opening.
The NOx generation model adopts a semi-empirical semi-physical model, as shown in formula 2, a reference NOx concentration is determined according to the rotating speed and the fuel injection quantity of the engine, the reference NOx concentration is multiplied by the correction based on the oxygen concentration of the intake air, the correction multiplied by the fuel injection advance angle and the correction multiplied by the intake air temperature to obtain the NOx concentration of the model. Wherein n represents the engine speed, q represents the fuel injection quantity, r _ o2act/r represents the actual oxygen concentration, r _ o2ref represents the reference oxygen concentration, f (angle) represents the advance angle of fuel injection, T 22 Indicating intake manifold temperature, T 22ref Indicating an intake manifold reference temperature.
The exhaust temperature model, as shown in equation 3, determines a reference exhaust temperature from the engine speed and the injected fuel quantity, multiplies the reference exhaust temperature by a correction based on the intake oxygen concentration, multiplies the correction by the engine water temperature, and multiplies the correction by the intake air temperature to obtain a model exhaust temperature. The gas pressure of each pipeline component is calculated using the gas equation PV = MRT for the pipeline. Wherein Tref (n, q) is a reference exhaust gas temperature, f (r _ o2act/r _ o2 ref) is a correction value based on the intake oxygen concentration, g (Teng) is a correction value of the engine water temperature, and h (T 22 ) A correction value representing the intake air temperature.
1)M f ＝f(P2/P1)*Area*g(u)；
2)NOx＝NOx_ref(n,q)*(r_o2act/r_o2ref)a*f(angle)*g(T 22 /T 22ref )；
3)T＝Tref(n,q)*f(r_o2act/r_o2ref)*g(Teng)*h(T 22 )。
As is apparent from the above description, the original engine model can be used to output the engine intake pipe pressure, intake oxygen concentration NOx emission, exhaust gas temperature, exhaust gas flow rate, exhaust gas pressure, and the like.
S102: calculating the predicted values of the exhaust temperature of the engine and the primary NOx by using a preset formula with the lowest oil consumption as the target; the preset formula represents the corresponding relation among the exhaust gas flow, the engine exhaust temperature, the primary exhaust NOx, the DPF pressure difference and the oil consumption;
for example, the following steps are carried out: the preset formula may be expressed by the following formula 4):
4)min{bsfc＝g eng (m f ,T DOC ,NO X ,Δp)}；
wherein bsfc represents fuel consumption, m f Indicating the exhaust gas flow, T DOC Indicating engine exhaust temperature, NOx indicating raw NOx, and Δ p indicating DPF differential pressure.
In this embodiment, the method for solving equation 4) includes multiple methods, which are not limited in this embodiment, and preferably, the predicted values of the engine exhaust temperature and the primary NOx corresponding to the minimum oil consumption may be calculated by using a least square method.
S103: under the condition of meeting a preset condition, controlling the engine through the predicted values of the engine exhaust temperature and the primary NOx;
the preset conditions include: the current SCR temperature is larger than or equal to the limit value of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the corresponding original NOx under the current working condition.
In this embodiment, the precondition for reducing fuel consumption is that CO is satisfied 2 Further, in order to ensure that CO is met 2 The emission standard needs to make the SCR efficiency meet a certain condition, and in this embodiment, the SCR efficiency can be embodied by the SCR temperature and the raw NOx, so the condition meeting the SCR efficiency at least includes: the current SCR temperature is larger than or equal to the SCR temperature limit value corresponding to the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value corresponding to the original NOx under the current working condition.
The obtaining modes of the ranges of the SCR temperature limit values corresponding to different working conditions and the upper limit value and the lower limit value of the original NOx under different working conditions may include multiple types, for example, the obtaining modes may be calibrated in advance, that is, the upper limit value and the lower limit value of parameters corresponding to different working conditions and the SCR temperature limit value and the original NOx are calibrated in advance.
Preferably, the method for determining the SCR temperature limit value corresponding to the current operating condition and the upper limit value and the lower limit value of the NOx originally emitted under the current operating condition will be described in detail below, and details are not repeated in this embodiment.
In this embodiment, a second MAP representing a correspondence relationship between the actual efficiency of the SCR, the deviation of the original efficiency, and the limit value of the SCR temperature is preset.
The setting of the second MAP may be obtained through experiments in advance, that is, the CO is guaranteed 2 In the case of the emission standard, SCR temperatures corresponding to deviations of actual efficiencies and original efficiencies of different SCRs are determined in advance through experiments.
Further, besides ensuring that the emission standard of CO2 is met, the normal execution of the aftertreatment system needs to be further ensured, and under the condition of the requirement, the DPF differential pressure needs to be ensured within a preset DPF differential pressure limit value, specifically, the method further includes:
the current DPF pressure difference is less than or equal to a preset DPF pressure difference limit value under the current working condition;
the PDF differential pressure limit is determined from the current exhaust gas flow and a predetermined exhaust gas flow versus DPF differential pressure limit.
In this embodiment, controlling the engine may be controlling some parameters of the engine to achieve the purpose of reducing oil consumption, and preferably, the controlling of the engine may include: the method comprises the steps of primary NOx control and engine exhaust temperature closed-loop control, specifically, S103 comprises the following steps:
determining a first engine parameter through the engine exhaust temperature and a preset third MAP; the preset third MAP represents the relation between the first engine parameter and the engine exhaust temperature; the first engine parameter is a parameter related to engine control of primary NOx release;
acquiring an actual value of the current engine exhaust temperature, and calculating temperature deviation according to the actual value of the engine exhaust temperature and a predicted value of the engine exhaust temperature;
determining a second engine parameter according to a preset relationship between the second engine parameter and the temperature deviation;
controlling an engine based on the first and second engine parameters.
Preferably, the first engine parameters include at least: advance angle, rail pressure, intake oxygen concentration and intake pressure.
The second engine parameter includes: post-injection oil quantity and intake pressure.
The closed-loop control of the engine exhaust temperature is implemented by taking the predicted value of the optimized engine exhaust temperature as a target, performing PID (proportion integration differentiation) closed-loop control, and mainly adjusting the post-injection oil quantity and the intake pressure by taking the predicted value of the optimized engine exhaust temperature as a target.
In the embodiment, the predicted values of the exhaust temperature of the engine and the original exhaust NOx are calculated through a preset formula with the aim of lowest oil consumption; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption; under the condition of meeting a preset condition, controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx; the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition. Therefore, the purpose of optimizing the oil consumption is achieved on the premise of guaranteeing the CO2 emission standard.
Further, in order to ensure the SCR efficiency, the SCR efficiency can be adjusted by adjusting the amount of uremia injection, and specifically, the method further includes:
calculating the SCR efficiency deviation according to the basic efficiency deviation and the original machine efficiency deviation;
determining an ammonia storage set value based on a preset relationship between SCR efficiency deviation and ammonia storage;
determining a urea injection correction from the ammonia storage setpoint;
a target urea injection amount is determined based on the feed-forward efficiency injection amount and the urea injection amount.
Example 2
On the basis of the foregoing embodiment 1, referring to fig. 2, a flowchart for determining a current SCR temperature limit and an upper limit and a lower limit of a raw NOx according to an embodiment of the present invention is shown, and includes:
s201: acquiring the actual efficiency of the SCR and the efficiency of an SCR model, and calculating the deviation of the basic efficiency according to the actual efficiency of the SCR and the efficiency of the SCR model;
s202: determining an interpolation factor corresponding to the basic efficiency deviation;
the actual efficiency of the SCR can be obtained through NOx sensors at the upstream and downstream of the SCR, and then the actual efficiency of the SCR is calculated through the NOx concentrations at the upstream and downstream.
The efficiency of the SCR model is determined by a pre-constructed SCR model, the SCR model has the capability of normal operation of the model SCR, and the SCR model comprises; the system comprises a temperature model, an SCR adsorption and desorption model, an SCR reaction model, an SCR ammonia storage model, an SCR efficiency model and an SCR oxidation model, wherein the SCR temperature model is used for calculating the average temperature of SCR and the outlet temperature of SCR, the SCR model receives both PDF downstream model quantity (NO 2, temperature, flow and the like) and actual urea injection, the SCR adsorption and desorption model calculates ammonia adsorption and desorption quantity, the SCR oxidation model calculates ammonia oxidation quantity, the SCR reaction model calculates ammonia quantity of NOx reaction, the SCR ammonia storage model calculates ammonia storage quantity in SCR, and the SCR efficiency model calculates NOx conversion efficiency in SCR or expresses as SCR model efficiency.
The SCR model can be constructed in various ways, preferably can be constructed specifically through a kinetic equation and a normal SCR condition, and accordingly the capability of simulating the normal operation of the SCR is achieved.
For example, the SCR kinetic equation can be expressed by the following formula 1) to formula 4):
1)
Figure BDA0003184501750000091
2)
Figure BDA0003184501750000092
3)
Figure BDA0003184501750000093
4)
Figure BDA0003184501750000094
wherein, k: frequency factor, E: activation energy, J/molR: unified gas constant, 8.3145, J/mol/kT: temperature, θ: amount of ammonia stored in SCR, K θ: SCR catalyst ammonia coverage, epsilon: desorption of the nonlinear part, r: reaction rate, mol/m3/s, C: reaction concentration mol/m3.
In this embodiment, the base efficiency deviation is related to a difference between the actual efficiency of the SCR and the efficiency of the SCR model.
The base efficiency deviation and the interpolation factor are preset in a corresponding relationship, for example, the interpolation factor may be any value, for example, when the base efficiency deviation is 10%, the interpolation factor may be 1 or may also be 10, and the specific value is not limited.
S203: acquiring current SCR temperature and exhaust gas flow, and determining at least one efficiency distribution factor MAP based on the current SCR temperature and flow; the efficiency distribution factor MAP is expressed as the proportion distributed by different modes for adjusting the SCR efficiency deviation;
in this embodiment, the current SCR temperature is an actual temperature of the SCR, and may be obtained through actual measurement by a sensor. The current exhaust gas flow is also the actual exhaust gas flow, which can be actually measured by a sensor.
In this embodiment, the adjustment modes for the SCR efficiency may include multiple types, wherein different duty ratios may be set in advance for different adjustment modes in order to achieve the purpose of adjusting the SCR, and the SCR efficiency is adjusted by the duty ratios. For example, the SCR adjustment mode may include: and adjusting the post-treatment urea poison injection or adjusting the engine primary NOx.
Each efficiency distribution factor MAP represents a ratio allocated for different ways of adjusting the SCR efficiency deviation, and in order to achieve different effects, different distribution ratios can be set, that is, different efficiency distribution factors MAP are set. Also, the SCR temperature and exhaust flow and efficiency distribution factor MAP are preset.
S204: interpolating at least one efficiency distribution factor by using the interpolation factor to obtain a target efficiency distribution factor MAP;
in this embodiment, at least one efficiency allocation factor may be interpolated by an interpolation factor, so as to obtain a target efficiency allocation factor MAP corresponding to the interpolation factor, or may be understood as obtaining a target efficiency allocation factor MAP corresponding to a base efficiency deviation.
S205: calculating the original computer efficiency deviation according to the basic efficiency deviation and the target efficiency distribution factor;
in this embodiment, the calculation of the original efficiency deviation may include various manners, such as obtaining the original efficiency deviation by multiplying the basic efficiency deviation by the target efficiency distribution factor, or obtaining the original efficiency deviation by multiplying the basic efficiency deviation by the target efficiency distribution factor by weighting.
S206: determining an upper limit value and a lower limit value of the corresponding primary NOx under the current working condition based on the deviation of the actual efficiency and the original machine efficiency of the SCR and a preset first MAP; the first MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency, the upper limit value of the original NOx and the lower limit value of the original NOx;
in this embodiment, a first MAP representing the correspondence relationship between the actual efficiency of the SCR and the deviation of the original engine efficiency and the upper limit value and the lower limit value of the original NOx is set in advance.
The setting of the first MAP may be obtained through experiments in advance, that is, the CO is guaranteed 2 In the case of the emission standard, the upper limit value and the lower limit value of the raw NOx corresponding to the actual efficiency and the deviation of the raw efficiency of the different SCRs are determined in advance through experiments.
S207: determining a lower limit value of the SCR temperature based on the actual SCR efficiency, the original machine efficiency deviation and a preset second MAP; and the second MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency and the lower limit value of the SCR temperature.
In the embodiment, the actual temperature of the SCR and the primary NOx are limited, so that the SCR efficiency is ensured to meet the preset conditions, and the emission requirement of CO2 is further ensured to be met.
Example 3
On the basis of the foregoing embodiment 1 and embodiment 2, referring to fig. 3, a schematic structural diagram of a post-processing model provided in an embodiment of the present invention is shown, and in this embodiment, the post-processing model includes:
DOC efficiency model 301, DPF efficiency model 302, SCR efficiency model 303;
the DOC efficiency model has an input end receiving some parameters of the engine output;
the output of the DPF efficiency model is connected with the input of the DPF efficiency model;
the output of the DPF efficiency model is connected with the input of the SCR efficiency model;
and controlling the engine model through the optimization control method to adjust the parameters input into the DOC efficiency model by the engine.
The DOC model comprises a temperature model and an efficiency model, the DOC model receives the exhaust gas temperature, the exhaust gas flow and the original NOx, the temperature model calculates the DOC internal average temperature and the DOC outlet temperature, and the efficiency model calculates the DOC outlet NO2 concentration.
The DPF model comprises a carbon loading capacity model, a passive regeneration model, a temperature model and a DPF efficiency model, the DPF model receives DOC model output quantity (NO 2, temperature, flow and the like) and engine original exhaust root quantity and the like, the carbon loading capacity model calculates carbon accumulation quantity in the current DPF, the passive regeneration model calculates carbon quantity reacted by NO2, the temperature model calculates DPF average temperature and DPF outlet temperature, and the DPF efficiency model calculates NO2 content at a DPF outlet.
The SCR model comprises a temperature model, an SCR adsorption and desorption model, an SCR reaction model, an SCR ammonia storage model, an SCR efficiency model and an SCR oxidation model, the temperature model calculates the average temperature of SCR and the outlet temperature of SCR, the SCR model receives the downstream model quantity (NO 2, temperature, flow rate and the like) of the DPF and the actual urea injection quantity, the SCR adsorption and desorption model calculates the ammonia adsorption and desorption quantity, the SCR oxidation model calculates the ammonia oxidation quantity, the SCR reaction model calculates the ammonia quantity of NOx reaction, the SCR ammonia storage model calculates the ammonia storage quantity in the SCR, and the SCR efficiency model calculates the conversion efficiency of NOx in the SCR.
As shown in fig. 4, an optimized control process for an integrated control model is shown, comprising:
the SCR conversion efficiency is related to the current exhaust gas flow rate at the upstream of the catalyst, the temperature, the NO2 proportion, the NOx concentration, the ammonia storage and the like, and as shown in formula 5, the SCR conversion efficiency constitutes a source and is converted into the following three parts as shown in formula 6: the method comprises the steps of engine original machine emission control, DOC/DPF temperature delay and NO2 proportion control and SCR ammonia storage control. The emission of the original engine and the storage of SCR ammonia are controllable objects, and low oil consumption and SCR efficiency can be realized and DPF passive regeneration efficiency can be optimized by optimizing and adjusting different set values.
4)η＝f(m f ,T scr ,NO 2 ,NO X ,θ)；
5)η＝f eng (m f ,T DOC ,NO X )*f doc/dpf (m f ,T DOC ,NO X )*f scr (θ)；
Wherein m is f Indicating exhaust gas flow rate, tscr SCR temperature, NO2 ratio, theta ammonia storage, T DOC Representing engine exhaust temperature, feng () representing a function related to engine exhaust temperature control, fdoc/DPF () representing a function related to DOC/DPF temperature delay and NO2 proportional control, f scr A function relating to ammonia storage control is shown.
The optimization of the SCR self-optimization setting value is realized by the above-mentioned optimization control method, so as to obtain the predicted values of engine exhaust temperature and primary NOx, and then the engine is controlled by the obtained transmitter exhaust temperature and the predicted values of the primary NOx, that is, some parameters of the engine are controlled by the temperature closed-loop control model and the primary NOx control model, for example, determining the first engine parameter by the predicted value of the primary NOx at least includes: advance angle, rail pressure, intake oxygen concentration and intake pressure; determining and controlling the model with the original engine NOx through the second engine parameter, wherein the model comprises the following steps: post-injection oil quantity and intake pressure. After the adjusted first engine parameter and the adjusted second engine parameter act on the engine, not only is the oil consumption reduced, but also information of some parameters input into the DOC efficiency model, such as the exhaust gas flow, the exhaust gas temperature and the primary NOx, is adjusted, and then the integrated control of the aftertreatment model is realized.
Furthermore, the ammonia storage can be subjected to closed-loop control in a mode of optimizing a set value by SCR self-tendency, and the SCR efficiency can be adjusted by adjusting the urea injection amount.
Example 4
Referring to fig. 5, a schematic structural diagram of an optimization control apparatus according to an embodiment of the present invention is shown, in this embodiment, the apparatus includes:
an obtaining unit 501, configured to obtain a current exhaust gas flow rate and a DPF differential pressure;
the prediction unit 502 is used for calculating the prediction values of the engine exhaust temperature and the primary exhaust NOx by using a preset formula with the aim of minimum oil consumption; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption;
the optimization control unit 503 is configured to control the engine according to the predicted values of the engine exhaust temperature and the primary NOx when a preset condition is satisfied;
the preset conditions include: and the current SCR actual temperature is greater than or equal to the lower limit value of the SCR temperature corresponding to the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition.
Optionally, the method further includes:
a limit determination unit to:
acquiring the actual efficiency of the SCR and the efficiency of an SCR model, and calculating the deviation of the basic efficiency according to the actual efficiency of the SCR and the efficiency of the SCR model;
determining an interpolation factor corresponding to the basic efficiency deviation;
acquiring the current SCR temperature and flow, and determining at least one efficiency distribution factor MAP based on the current SCR temperature and flow; the efficiency distribution factor MAP is expressed as the ratio of different adjustment SCR efficiency deviation distributions;
interpolating at least one efficiency distribution factor by using the interpolation factor to obtain a target efficiency distribution factor MAP;
calculating the original computer efficiency deviation according to the basic efficiency deviation and the target efficiency distribution factor;
determining an upper limit value and a lower limit value of the corresponding primary NOx under the current working condition based on the deviation of the actual efficiency and the original machine efficiency of the SCR and a preset first MAP; the first MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency, the upper limit value of the original NOx and the lower limit value of the original NOx;
determining a lower limit value of the SCR temperature based on the actual SCR efficiency, the original machine efficiency deviation and a preset second MAP; and the second MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency and the lower limit value of the SCR temperature.
Optionally, the preset condition further includes:
the current DPF pressure difference is less than or equal to a preset DPF pressure difference limit value under the current working condition;
the current DPF pressure difference is less than or equal to a DPF pressure difference limit value preset under the current working condition;
the PDF differential pressure limit is determined by the current exhaust gas flow and a preset exhaust gas flow versus DPF differential pressure limit.
Optionally, the optimization control unit includes:
the first determining subunit is used for determining a first engine parameter through the engine exhaust temperature and a preset third MAP; the preset third MAP represents the relation between the first engine parameter and the engine exhaust temperature; the first engine parameter is a parameter related to engine control of primary NOx;
the calculation subunit is used for acquiring the current actual engine exhaust temperature and calculating the temperature deviation according to the current actual engine exhaust temperature and the predicted engine exhaust temperature;
the second determining subunit is used for determining a second engine parameter according to the preset relationship between the second engine parameter and the temperature deviation; the second engine parameter is a parameter related to controlling engine exhaust temperature;
and the optimization control subunit is used for controlling the engine based on the first engine parameter and the second engine parameter.
Optionally, the first engine parameter at least includes: advance angle, rail pressure, intake oxygen concentration and intake pressure.
Optionally, the second engine parameter comprises: post-injection oil quantity and intake pressure.
By the device of the embodiment, the predicted value of the exhaust temperature of the engine and the original NOx is calculated by a preset formula with the aim of lowest oil consumption; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption; under the condition of meeting a preset condition, controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx; the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition. Therefore, the purpose of optimizing the oil consumption is achieved on the premise of guaranteeing the CO2 emission standard. .
Example 5
Referring to fig. 6, a schematic structural diagram of an electronic device according to an embodiment of the present invention is shown, where in this embodiment, the electronic device includes:
a memory 601 and a processor 602;
the memory is configured to store a program, and the processor is configured to execute the optimization control method disclosed above when executing the program stored in the memory, which is not described in detail in this embodiment.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An optimization control method, comprising:
acquiring the current exhaust gas flow and DPF pressure difference;
calculating the predicted values of the exhaust temperature of the engine and the primary NOx by using a preset formula with the lowest oil consumption as the target; the preset formula represents the corresponding relation among the exhaust gas flow, the exhaust temperature of an engine, the primary exhaust NOx, the pressure difference of a DPF and the oil consumption;
under the condition of meeting a preset condition, controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx;
the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition.
2. The method of claim 1, further comprising:
acquiring SCR actual efficiency and SCR model efficiency, and calculating basic efficiency deviation according to the SCR actual efficiency and the SCR model efficiency;
determining an interpolation factor corresponding to the basic efficiency deviation;
acquiring the current SCR temperature and flow, and determining at least one efficiency distribution factor MAP based on the current SCR temperature and flow; the efficiency distribution factor MAP is expressed as the ratio of different adjustment SCR efficiency deviation distributions; the SCR efficiency deviation is obtained by calculation according to the basic efficiency deviation and the original machine efficiency deviation;
interpolating at least one efficiency distribution factor by using the interpolation factor to obtain a target efficiency distribution factor MAP;
calculating the original computer efficiency deviation according to the basic efficiency deviation and the target efficiency distribution factor;
determining an upper limit value and a lower limit value of the corresponding primary NOx under the current working condition based on the deviation of the actual efficiency and the original machine efficiency of the SCR and a preset first MAP; the first MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency, the upper limit value of the original NOx and the lower limit value of the original NOx;
determining a lower limit value of the SCR temperature based on the actual SCR efficiency, the original machine efficiency deviation and a preset second MAP; and the second MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency and the lower limit value of the SCR temperature.
3. The method of claim 1, wherein the preset condition further comprises:
the current DPF pressure difference is less than or equal to a preset DPF pressure difference limit value under the current working condition;
the DPF pressure differential limit is determined from the current exhaust flow and a preset exhaust flow versus DPF pressure differential limit.
4. The method of claim 1, wherein the controlling the engine via engine-out and raw NOx comprises:
determining a first engine parameter through the engine exhaust temperature and a preset third MAP; the preset third MAP represents the relation between the first engine parameter and the engine exhaust temperature; the first engine parameter is a parameter related to engine control of primary NOx;
acquiring the current actual engine exhaust temperature, and calculating the temperature deviation according to the current actual engine exhaust temperature and the predicted engine exhaust temperature;
determining a second engine parameter according to a preset relationship between the second engine parameter and the temperature deviation; the second engine parameter is a parameter related to controlling engine exhaust temperature;
controlling an engine based on the first and second engine parameters.
5. The method of claim 4, wherein the first engine parameters include at least: the fuel injection advance angle, the rail pressure, the intake oxygen concentration and the intake pressure.
6. The method of claim 5, wherein the second engine parameter comprises: post-injection oil quantity and intake pressure.
7. An optimization control apparatus, comprising:
an acquisition unit for acquiring a current exhaust gas flow rate and a DPF differential pressure;
the prediction unit is used for calculating the prediction value of the exhaust temperature of the engine and the original NOx through a preset formula with the aim of lowest oil consumption; the preset formula represents the corresponding relation among the exhaust gas flow, the engine exhaust temperature and the primary exhaust NOx, the DPF pressure difference and the oil consumption;
the optimization control unit is used for controlling the engine through the predicted values of the exhaust temperature of the engine and the primary NOx under the condition of meeting the preset conditions;
the preset conditions include: the actual temperature of the current SCR is larger than or equal to the lower limit value of the temperature of the corresponding SCR under the current working condition, and the original NOx is in the range of the upper limit value and the lower limit value of the original NOx corresponding to the current working condition.
8. The apparatus of claim 7, further comprising:
a limit determination unit to:
acquiring the actual efficiency of the SCR and the efficiency of an SCR model, and calculating the deviation of the basic efficiency according to the actual efficiency of the SCR and the efficiency of the SCR model;
determining an interpolation factor corresponding to the basic efficiency deviation;
acquiring the current SCR temperature and flow, and determining at least one efficiency distribution factor MAP based on the current SCR temperature and flow; the efficiency distribution factor MAP is expressed as the ratio of the distribution of the deviation of the efficiency of different regulating SCRs; the SCR efficiency deviation is obtained by calculation according to the basic efficiency deviation and the original machine efficiency deviation;
interpolating at least one efficiency distribution factor by using the interpolation factor to obtain a target efficiency distribution factor MAP;
calculating the original computer efficiency deviation according to the basic efficiency deviation and the target efficiency distribution factor;
determining an upper limit value and a lower limit value of the corresponding primary NOx under the current working condition based on the deviation of the actual efficiency and the original machine efficiency of the SCR and a preset first MAP; the first MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency, the upper limit value of the original NOx and the lower limit value of the original NOx;
determining a lower limit value of the SCR temperature based on the actual SCR efficiency, the original machine efficiency deviation and a preset second MAP; and the second MAP represents the corresponding relation between the actual efficiency of the SCR, the deviation of the original machine efficiency and the lower limit value of the SCR temperature.
9. The apparatus of claim 7, wherein the preset condition further comprises:
the current DPF pressure difference is less than or equal to a preset DPF pressure difference limit value under the current working condition;
the DPF pressure differential limit is determined from the current exhaust flow and a preset exhaust flow versus DPF pressure differential limit.
10. An electronic device, comprising:
a memory and a processor;
the memory is used for storing programs, and the processor is used for executing the optimization control method of any one of the claims 1-6 when executing the programs stored in the memory.
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