CN113482783A - NOx emission level regulation and control method and device - Google Patents
NOx emission level regulation and control method and device Download PDFInfo
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- CN113482783A CN113482783A CN202110866274.9A CN202110866274A CN113482783A CN 113482783 A CN113482783 A CN 113482783A CN 202110866274 A CN202110866274 A CN 202110866274A CN 113482783 A CN113482783 A CN 113482783A
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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
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
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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
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/0047—Controlling exhaust gas recirculation [EGR]
- F02D41/0077—Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position
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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
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
- F02D41/146—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration
- F02D41/1461—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration of the exhaust gases emitted by the engine
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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
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1486—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor with correction for particular operating conditions
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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
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/38—Controlling fuel injection of the high pressure type
- F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
- F02D41/401—Controlling injection timing
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- 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
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- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Exhaust-Gas Circulating Devices (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
The application relates to a method and a device for regulating and controlling the NOx emission level, which relate to the technical field of NOx emission regulation and control, and the method comprises the following steps: monitoring a real-time NOx emission level of the vehicle; monitoring the real-time rotating speed and the real-time torque of an engine of the vehicle to obtain the corresponding standard emission level of NOx; when the real-time NOx deviation value is greater than the first deviation threshold, the fuel injection timing or EGR rate of the vehicle is adjusted such that the real-time NOx deviation value in response to the adjusted real-time NOx emission level and the standard NOx emission level is less than the deviation permitting threshold. The method compares the real-time NOx emission level with the current corresponding NOx standard emission level of the vehicle engine, and adjusts the fuel injection timing or EGR rate of the vehicle according to the deviation value of the real-time NOx emission level and the current corresponding NOx standard emission level of the vehicle engine, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
Description
Technical Field
The application relates to the technical field of NOx emission regulation and control, in particular to a method and a device for regulating and controlling the NOx emission level.
Background
The main gaseous emission of diesel engines is NOx, and there are currently well-defined restrictions on NOx emission levels in the vehicle industry, and the current main technical route strategy for NOx is to reduce the NOx emission levels by aftertreatment.
The original NOx emission level of the diesel engine has direct influence on system NOx emission, and main factors influencing the NOx emission level include engine rail pressure, fuel injection timing, EGR rate and the like. The production consistency of the engine has certain influence on the original machine NOx emission level, and how to ensure the original machine NOx emission consistency is particularly important in the production process of the engine and is important in realizing closed-loop control on NOx emission to ensure the original NOx emission level.
To solve the above technical problems, a NOx emission level regulation and control technology is now provided to meet the current demand.
Disclosure of Invention
The application provides a method and a device for regulating and controlling NOx emission level, which are used for comparing the real-time NOx emission level with the current corresponding NOx standard emission level of a vehicle engine and regulating the fuel injection timing or EGR rate of the vehicle according to the deviation value of the real-time NOx emission level and the current corresponding NOx standard emission level of the vehicle engine, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
In a first aspect, the present application provides a method of regulating NOx emission levels, the method comprising the steps of:
monitoring a real-time NOx emission level of the vehicle;
monitoring the real-time rotating speed and the real-time torque of an engine of the vehicle, and obtaining the corresponding standard emission level of NOx;
when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, adjusting the fuel injection timing or the EGR rate of the vehicle so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level after response adjustment is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
and the adjustment value when the EGR rate is adjusted corresponds to the change value of the real-time NOx emission level.
In the specific implementation process of the application, the specific operation flow is as follows:
in step S1, monitoring the real-time NOx emission level of the vehicle using a preset NOx sensor;
in step S2, using corresponding sensors or other devices, monitoring the real-time engine speed and the real-time engine torque of the vehicle, and comparing a first MAP to obtain a corresponding NOx standard emission level, where the abscissa of the first MAP is the engine speed and the ordinate of the first MAP is the NOx emission target basis corresponding to the engine load, i.e. the NOx standard emission level;
in step S3, a second MAP is used, wherein the abscissa of the second MAP is the engine speed, and the ordinate of the second MAP is the maximum limit of the NOx emission deviation of the engine load, i.e. the first deviation threshold, in the implementation process of step S3, the first deviation threshold is obtained by combining the second MAP according to the real-time engine speed, and the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is compared with the first deviation threshold, when the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is greater than the first deviation threshold, the fuel injection timing or EGR rate of the vehicle is adjusted so that the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is less than the preset deviation allowable threshold,
in addition, when the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is not greater than the first deviation threshold, it indicates that no adjustment of the fuel injection timing or EGR rate of the vehicle is required.
In the application, the real-time NOx emission level is compared with the current corresponding NOx standard emission level of the vehicle engine, and the fuel injection timing or EGR rate of the vehicle is adjusted according to the deviation value of the real-time NOx emission level and the current corresponding NOx standard emission level of the vehicle engine, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
In addition, the embodiment of the application further distributes the adjusting weight coefficients corresponding to the fuel injection timing and the EGR rate of the vehicle based on the rotating speed and the torque of the engine, and adjusts the adjusting weight coefficients based on the corresponding adjusting weight coefficients, so that the basis is provided for the accuracy and the reliability of the NOx emission regulation.
Further, the NOx emission level regulation method further includes the steps of:
and when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a preset second deviation threshold value, forbidding the adjustment of the fuel injection timing or the EGR rate of the vehicle, and carrying out NOx emission alarm.
Specifically, the first deviation threshold corresponds to an engine load corresponding to the real-time engine speed.
Specifically, the adjusting of the fuel injection timing or the EGR rate of the vehicle includes:
obtaining a first adjusting weight coefficient and a second adjusting weight coefficient based on the real-time rotating speed of the engine and the corresponding engine load;
adjusting the fuel injection timing or the EGR rate of the vehicle based on the first adjusting weight coefficient and the second adjusting weight coefficient; wherein the content of the first and second substances,
the first adjustment weight coefficient corresponds to the injection timing, and the second adjustment weight coefficient corresponds to the EGR rate.
Specifically, the maximum value of the first adjustment weight coefficient and the second adjustment weight coefficient is 1, the minimum value thereof is 0, and the sum of the first adjustment weight coefficient and the second adjustment weight coefficient is 1.
In a second aspect, the present application provides a NOx emission level regulating device, the device comprising:
a NOx emission monitoring module for monitoring a NOx real-time emission level of a vehicle;
the engine monitoring module is used for monitoring the real-time rotating speed and the real-time torque of the engine of the vehicle;
the NOx emission calibration module is used for obtaining a corresponding NOx standard emission level according to the real-time rotating speed of the engine and the real-time torque of the engine;
the NOx emission control module is used for adjusting the fuel injection timing or EGR rate of the vehicle when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level after response adjustment is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
and the adjustment value when the EGR rate is adjusted corresponds to the change value of the real-time NOx emission level.
Further, the NOx emission level regulation apparatus further includes:
and the NOx emission warning module is used for forbidding to adjust the fuel injection timing or the EGR rate of the vehicle and carrying out NOx emission warning when the real-time NOx deviation value of the real-time NOx emission level and the standard NOx emission level is larger than a preset second deviation threshold value.
Specifically, the first deviation threshold corresponds to an engine load corresponding to the real-time engine speed.
Further, the NOx emission regulation and control module is also used for obtaining a first regulation weight coefficient and a second regulation weight coefficient based on the real-time rotating speed of the engine and the corresponding engine load;
the NOx emission control module is further used for adjusting the fuel injection timing or the EGR rate of the vehicle based on the first adjusting weight coefficient and the second adjusting weight coefficient; wherein the content of the first and second substances,
the first adjustment weight coefficient corresponds to the injection timing, and the second adjustment weight coefficient corresponds to the EGR rate.
Preferably, the maximum value of the first adjustment weight coefficient and the second adjustment weight coefficient is 1, the minimum value thereof is 0, and the sum of the first adjustment weight coefficient and the second adjustment weight coefficient is 1.
The beneficial effect that technical scheme that this application provided brought includes:
(1) the method compares the real-time NOx emission level with the current corresponding NOx standard emission level of the vehicle engine, and adjusts the fuel injection timing or EGR rate of the vehicle according to the deviation value of the real-time NOx emission level and the current corresponding NOx standard emission level of the vehicle engine, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
(2) According to the method and the device, based on the rotating speed and the torque of the engine, the adjusting weight coefficients corresponding to the fuel injection timing and the EGR rate of the vehicle are further distributed, and adjustment is performed based on the corresponding adjusting weight coefficients, so that a basis is provided for the accuracy and the reliability of NOx emission regulation.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a flow chart of the steps of a NOx emission level adjustment method provided in an embodiment of the present application;
FIG. 2 is a functional block diagram illustrating the decision in a NOx emission level adjustment method provided in an embodiment of the present application;
FIG. 3 is a functional block diagram of a modification in the NOx emission level adjustment method provided in the embodiment of the present application;
fig. 4 is a block diagram of the structure of a NOx emission level regulation device provided in the embodiment of the present application.
Detailed Description
Interpretation of terms:
EGR, Exhaust Gas Re-circulation, Exhaust Gas recirculation system.
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
The embodiment of the application provides a method and a device for regulating and controlling NOx emission level, which are used for comparing the real-time NOx emission level with the current corresponding NOx standard emission level of a vehicle engine and regulating the fuel injection timing or EGR rate of the vehicle according to the deviation value of the real-time NOx emission level and the current corresponding NOx standard emission level of the vehicle engine, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
In order to achieve the technical effects, the general idea of the application is as follows:
a method of NOx emission level regulation, the method comprising the steps of:
s1, monitoring the NOx real-time emission level of the vehicle;
s2, monitoring the real-time rotating speed and the real-time torque of the engine of the vehicle, and obtaining the corresponding standard emission level of NOx;
s3, when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, adjusting the fuel injection timing or the EGR rate of the vehicle so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
the adjustment value when the EGR rate is adjusted corresponds to the change value of the NOx real-time emission level.
Embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
In a first aspect, and with reference to fig. 1-3, the present application provides a NOx emission level regulation method comprising the steps of:
s1, monitoring the NOx real-time emission level of the vehicle;
s2, monitoring the real-time rotating speed and the real-time torque of the engine of the vehicle, and obtaining the corresponding standard emission level of NOx;
s3, when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, adjusting the fuel injection timing or the EGR rate of the vehicle so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
the corresponding relation exists between the adjusting value when the EGR rate is adjusted and the change value of the real-time NOx emission level;
the real-time NOx emission level and the standard NOx emission level are specific values, which may also be referred to as a real-time NOx emission value and a standard NOx emission value, respectively.
It should be noted that most diesel engines are currently equipped with an aftertreatment system, and that the NOx sensor is configured to monitor the NOx emission level of the diesel engine in real time, which can be understood as the real-time NOx emission level,
in the original machine calibration process, the NOx original emission standard level of the engine at the current moment is calibrated according to the specific working condition MAP of the engine, namely the first MAP, the NOx original emission standard level is the NOx standard emission level, the corresponding NOx real-time deviation value is obtained by comparing the fed-back NOx real-time emission level with the NOx standard emission level,
and a determination time is set, in which the real-time deviation value of NOx is greater than the first deviation threshold value, it is determined that adjustment is required, i.e. adjustment of the injection timing and EGR rate is required,
in addition, when the NOx emission deviation is overlarge, specifically when the real-time NOx deviation value is larger than a second deviation threshold value, the economy of the engine can be obviously reduced by adjusting the fuel injection timing and the EGR rate, at the moment, an error should be reported, and the regulation and control work is abandoned; wherein the content of the first and second substances,
the second deviation threshold value has a value greater than the first deviation threshold value.
In the embodiment of the application, in the specific implementation process, the specific operation flow is as follows:
in step S1, monitoring the real-time NOx emission level of the vehicle using a preset NOx sensor;
in step S2, using corresponding sensors or other devices, monitoring the real-time engine speed and the real-time engine torque of the vehicle, and comparing a first MAP to obtain a corresponding NOx standard emission level, where the abscissa of the first MAP is the engine speed and the ordinate of the first MAP is the NOx emission target basis corresponding to the engine load, i.e. the NOx standard emission level;
in step S3, a second MAP is used, wherein the abscissa of the second MAP is the engine speed, and the ordinate of the second MAP is the maximum limit of the NOx emission deviation of the engine load, i.e. the first deviation threshold, in the implementation process of step S3, the first deviation threshold is obtained by combining the second MAP according to the real-time engine speed, and the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is compared with the first deviation threshold, when the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is greater than the first deviation threshold, the fuel injection timing or EGR rate of the vehicle is adjusted so that the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is less than the preset deviation allowable threshold,
in addition, when the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is not greater than the first deviation threshold, it indicates that no adjustment of the fuel injection timing or EGR rate of the vehicle is required.
In the embodiment of the application, the real-time NOx emission level is compared with the current NOx standard emission level corresponding to the vehicle engine, and the fuel injection timing or EGR rate of the vehicle is adjusted according to the deviation value of the real-time NOx emission level and the current NOx standard emission level, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
In addition, the embodiment of the application further distributes the adjusting weight coefficients corresponding to the fuel injection timing and the EGR rate of the vehicle based on the rotating speed and the torque of the engine, and adjusts the adjusting weight coefficients based on the corresponding adjusting weight coefficients, so that the basis is provided for the accuracy and the reliability of the NOx emission regulation.
Further, the NOx emission level regulation method further comprises the steps of:
and when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a preset second deviation threshold value, forbidding the adjustment of the fuel injection timing or the EGR rate of the vehicle, and carrying out NOx emission alarm.
Specifically, the first deviation threshold corresponds to an engine load corresponding to a real-time engine speed.
Specifically, the adjustment of the fuel injection timing or the EGR rate of the vehicle includes the steps of:
obtaining a first adjusting weight coefficient and a second adjusting weight coefficient based on the real-time rotating speed of the engine and the corresponding engine load;
adjusting the fuel injection timing or the EGR rate of the vehicle based on the first adjusting weight coefficient and the second adjusting weight coefficient; wherein the content of the first and second substances,
the first adjustment weight factor corresponds to the injection timing and the second adjustment weight factor corresponds to the EGR rate.
Specifically, the maximum value of the first adjustment weight coefficient and the second adjustment weight coefficient is 1, the minimum value thereof is 0, and the sum of the first adjustment weight coefficient and the second adjustment weight coefficient is 1.
Specifically, since both the engine adjustment timing and the EGR rate can adjust the NOx emission level, but at the same time, there is a certain influence on the fuel consumption rate of the engine, so there is a certain limit value for the adjustment range, and when the fuel injection timing or the EGR rate of the vehicle is adjusted, a weight distribution MAP, that is, a third MAP is configured;
when weight distribution is carried out on the weight distribution MAP, the weight distribution MAP is realized through calibration values, the abscissa of the third MAP is the engine speed, the ordinate of the third MAP is a weight coefficient of the engine load, when the calibration value of the third MAP is 1, only timing adjustment is adopted, when the calibration value of the third MAP is 0, only EGR adjustment is adopted, when the calibration value of the third MAP is a middle value a between 0 and 1, 100% of deviation distribution a exceeding NOx is adopted as timing adjustment, (1-a) 100% of deviation is adjusted by EGR rate;
when the timing is adjusted, based on the timing adjustment MAP, which can be also called as a fourth MAP, the abscissa of the timing adjustment MAP is the engine speed, the ordinate of the timing adjustment MAP is the engine load, and the amount of change of the NOx concentration (which can be calibrated) is inversely calculated according to the NOx concentration to be adjusted to adjust the timing control when the amount of change of the NOx concentration is adjusted by 1 degree;
similarly, when EGR adjustment is carried out, based on EGR adjustment MAP, also called as fifth MAP, the abscissa of the EGR adjustment MAP is engine speed, the ordinate is engine load, and the amount of change of NOx concentration at the time of every 1 degree of adjustment (the amount can be calibrated) is inversely calculated according to the NOx concentration required to be adjusted so as to carry out EGR adjustment;
the timing adjustment and the EGR rate adjustment are respectively provided with a corresponding maximum adjustment range limit MAP, the adjustment ranges cannot exceed the adjustment ranges corresponding to the maximum adjustment range limit MAP so as to ensure the economy and the smoke emission performance of the engine, and when the adjustment ranges reach the maximum adjustment range and exceed a certain time, a warning for diagnosing the NOx control fault can be prompted.
It should be noted that, in the embodiment of the present application, after it is determined that the NOx emission level needs to be adjusted, the adjustment is mainly achieved by adjusting the fuel injection timing and the EGR rate;
the original engine sets basic oil injection timing and EGR rate according to the rotating speed and load of the engine, but the oil injection timing and EGR rate have different NOx adjusting capacity and influence on the engine, and the adjusting weight needs to be distributed at the moment;
determining the weight of the NOx level to be adjusted of the fuel injection timing and the EGR rate according to the engine speed and the NOx deviation percentage, and calculating the NOx emission level to be adjusted of the fuel injection timing and the EGR rate under the current working condition;
when the NOx emission level of the injection timing which needs to be adjusted under the current working condition (rotating speed and torque) is calculated, the injection timing correction is calculated through the injection timing adjustment MAP to correct and adjust the current injection timing, the EGR correction is calculated through the EGR rate adjustment MAP to adjust the current EGR rate, and finally the NOx original emission level is ensured, namely the real-time NOx emission level is ensured to meet the requirement.
In a second aspect, as shown in fig. 4, based on the same design concept of the NOx emission level control method mentioned in the first aspect, an embodiment of the present application provides a NOx emission level control device, which includes:
a NOx emission monitoring module for monitoring a NOx real-time emission level of a vehicle;
the engine monitoring module is used for monitoring the real-time rotating speed and the real-time torque of the engine of the vehicle;
the NOx emission calibration module is used for obtaining a corresponding NOx standard emission level according to the real-time rotating speed of the engine and the real-time torque of the engine;
the NOx emission control module is used for adjusting the fuel injection timing or the EGR rate of the vehicle when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level after response adjustment is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
the corresponding relation exists between the adjusting value when the EGR rate is adjusted and the change value of the real-time NOx emission level;
the real-time NOx emission level and the standard NOx emission level are specific values, which may also be referred to as a real-time NOx emission value and a standard NOx emission value, respectively.
It should be noted that most diesel engines are currently equipped with an aftertreatment system, and that the NOx sensor is configured to monitor the NOx emission level of the diesel engine in real time, which can be understood as the real-time NOx emission level,
in the original machine calibration process, the NOx original emission standard level of the engine at the current moment is calibrated according to the specific working condition MAP of the engine, namely the first MAP, the NOx original emission standard level is the NOx standard emission level, the corresponding NOx real-time deviation value is obtained by comparing the fed-back NOx real-time emission level with the NOx standard emission level,
and a determination time is set, in which the real-time deviation value of NOx is greater than the first deviation threshold value, it is determined that adjustment is required, i.e. adjustment of the injection timing and EGR rate is required,
in addition, when the NOx emission deviation is overlarge, specifically when the real-time NOx deviation value is larger than a second deviation threshold value, the economy of the engine can be obviously reduced by adjusting the fuel injection timing and the EGR rate, at the moment, an error should be reported, and the regulation and control work is abandoned; wherein the content of the first and second substances,
the second deviation threshold value has a value greater than the first deviation threshold value.
In the embodiment of the application, in the specific implementation process, the specific operation flow is as follows:
firstly, the NOx emission monitoring module can be a NOx sensor, namely, a preset NOx sensor is utilized to monitor the NOx real-time emission level of the vehicle;
the engine monitoring module can be a corresponding sensor or other equipment, monitors the real-time rotating speed and the real-time torque of the engine of the vehicle, and obtains a corresponding NOx standard emission level by contrasting a first MAP, wherein the abscissa of the first MAP is the rotating speed of the engine, and the ordinate of the first MAP is a NOx emission target base corresponding to the load of the engine, namely the NOx standard emission level;
the NOx emission calibration module and the NOx emission regulation module work cooperatively, a second MAP is needed, the abscissa of the second MAP is engine speed, the ordinate of the second MAP is the maximum limit value of NOx emission deviation of engine load, namely a first deviation threshold, in the implementation process, the step S3 is firstly to combine the second MAP with the real-time engine speed to obtain the first deviation threshold, and then to compare the real-time NOx deviation value of the real-time NOx emission level and the standard NOx emission level with the first deviation threshold, when the real-time NOx deviation value of the real-time NOx emission level and the standard NOx emission level is greater than the first deviation threshold, the fuel injection timing or EGR rate of the vehicle is adjusted to enable the real-time NOx deviation value of the real-time NOx emission level and the standard NOx emission level after response adjustment to be less than the preset deviation allowable threshold,
in addition, when the real-time NOx deviation value of the real-time NOx emission level from the standard NOx emission level is not greater than the first deviation threshold, it indicates that no adjustment of the fuel injection timing or EGR rate of the vehicle is required.
In the embodiment of the application, the real-time NOx emission level is compared with the current NOx standard emission level corresponding to the vehicle engine, and the fuel injection timing or EGR rate of the vehicle is adjusted according to the deviation value of the real-time NOx emission level and the current NOx standard emission level, so that the NOx emission level is regulated and controlled, and the operation of the engine and the consistency of the NOx emission level are effectively guaranteed.
In addition, the embodiment of the application further distributes the adjusting weight coefficients corresponding to the fuel injection timing and the EGR rate of the vehicle based on the rotating speed and the torque of the engine, and adjusts the adjusting weight coefficients based on the corresponding adjusting weight coefficients, so that the basis is provided for the accuracy and the reliability of the NOx emission regulation.
Further, the NOx emission level regulation apparatus further includes:
and the NOx emission alarm module is used for forbidding the adjustment of the fuel injection timing or the EGR rate of the vehicle and carrying out NOx emission alarm when the real-time NOx deviation value of the real-time NOx emission level and the standard NOx emission level is larger than a preset second deviation threshold value.
Specifically, the first deviation threshold corresponds to an engine load corresponding to a real-time engine speed.
Further, the NOx emission regulation and control module is also used for obtaining a first regulation weight coefficient and a second regulation weight coefficient based on the real-time rotating speed of the engine and the corresponding engine load;
the NOx emission control module is also used for adjusting the fuel injection timing or the EGR rate of the vehicle based on the first adjusting weight coefficient and the second adjusting weight coefficient; wherein the content of the first and second substances,
the first adjustment weight factor corresponds to the injection timing and the second adjustment weight factor corresponds to the EGR rate.
Preferably, the maximum value of the first adjustment weight coefficient and the second adjustment weight coefficient is 1, the minimum value thereof is 0, and the sum of the first adjustment weight coefficient and the second adjustment weight coefficient is 1.
Specifically, since both the engine adjustment timing and the EGR rate can adjust the NOx emission level, but at the same time, there is a certain influence on the fuel consumption rate of the engine, so there is a certain limit value for the adjustment range, and when the fuel injection timing or the EGR rate of the vehicle is adjusted, a weight distribution MAP, that is, a third MAP is configured;
when weight distribution is carried out on the weight distribution MAP, the weight distribution MAP is realized through calibration values, the abscissa of the third MAP is the engine speed, the ordinate of the third MAP is a weight coefficient of the engine load, when the calibration value of the third MAP is 1, only timing adjustment is adopted, when the calibration value of the third MAP is 0, only EGR adjustment is adopted, when the calibration value of the third MAP is a middle value a between 0 and 1, 100% of deviation distribution a exceeding NOx is adopted as timing adjustment, (1-a) 100% of deviation is adjusted by EGR rate;
when the timing is adjusted, based on the timing adjustment MAP, which can be also called as a fourth MAP, the abscissa of the timing adjustment MAP is the engine speed, the ordinate of the timing adjustment MAP is the engine load, and the amount of change of the NOx concentration (which can be calibrated) is inversely calculated according to the NOx concentration to be adjusted to adjust the timing control when the amount of change of the NOx concentration is adjusted by 1 degree;
similarly, when EGR adjustment is carried out, based on EGR adjustment MAP, also called as fifth MAP, the abscissa of the EGR adjustment MAP is engine speed, the ordinate is engine load, and the amount of change of NOx concentration at the time of every 1 degree of adjustment (the amount can be calibrated) is inversely calculated according to the NOx concentration required to be adjusted so as to carry out EGR adjustment;
the timing adjustment and the EGR rate adjustment are respectively provided with a corresponding maximum adjustment range limit MAP, the adjustment ranges cannot exceed the adjustment ranges corresponding to the maximum adjustment range limit MAP so as to ensure the economy and the smoke emission performance of the engine, and when the adjustment ranges reach the maximum adjustment range and exceed a certain time, a warning for diagnosing the NOx control fault can be prompted.
It should be noted that, in the embodiment of the present application, after it is determined that the NOx emission level needs to be adjusted, the adjustment is mainly achieved by adjusting the fuel injection timing and the EGR rate;
the original engine sets basic oil injection timing and EGR rate according to the rotating speed and load of the engine, but the oil injection timing and EGR rate have different NOx adjusting capacity and influence on the engine, and the adjusting weight needs to be distributed at the moment;
determining the weight of the NOx level to be adjusted of the fuel injection timing and the EGR rate according to the engine speed and the NOx deviation percentage, and calculating the NOx emission level to be adjusted of the fuel injection timing and the EGR rate under the current working condition;
when the NOx emission level of the injection timing which needs to be adjusted under the current working condition (rotating speed and torque) is calculated, the injection timing correction is calculated through the injection timing adjustment MAP to correct and adjust the current injection timing, the EGR correction is calculated through the EGR rate adjustment MAP to adjust the current EGR rate, and finally the NOx original emission level is ensured, namely the real-time NOx emission level is ensured to meet the requirement.
It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing are merely exemplary embodiments of the present application and are presented to enable those skilled in the art to understand and practice the present application. 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 application. Thus, the present application 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. A method of NOx emission level regulation, characterized in that the method comprises the steps of:
monitoring a real-time NOx emission level of the vehicle;
monitoring the real-time rotating speed and the real-time torque of an engine of the vehicle, and obtaining the corresponding standard emission level of NOx;
when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, adjusting the fuel injection timing or the EGR rate of the vehicle so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level after response adjustment is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
and the adjustment value when the EGR rate is adjusted corresponds to the change value of the real-time NOx emission level.
2. The NOx emission level regulation method of claim 1, further comprising the steps of:
and when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a preset second deviation threshold value, forbidding the adjustment of the fuel injection timing or the EGR rate of the vehicle, and carrying out NOx emission alarm.
3. The NOx emission level regulation method according to claim 1, characterized in that:
the first deviation threshold corresponds to an engine load corresponding to the real-time engine speed.
4. The NOx emission level adjustment method according to claim 1, wherein the adjusting of the injection timing or the EGR rate of the vehicle comprises the steps of:
obtaining a first adjusting weight coefficient and a second adjusting weight coefficient based on the real-time rotating speed of the engine and the corresponding engine load;
adjusting the fuel injection timing or the EGR rate of the vehicle based on the first adjusting weight coefficient and the second adjusting weight coefficient; wherein the content of the first and second substances,
the first adjustment weight coefficient corresponds to the injection timing, and the second adjustment weight coefficient corresponds to the EGR rate.
5. The NOx emission level regulation method according to claim 4, characterized in that:
the maximum value of the first adjusting weight coefficient and the second adjusting weight coefficient is 1, the minimum value of the first adjusting weight coefficient and the second adjusting weight coefficient is 0, and the sum of the first adjusting weight coefficient and the second adjusting weight coefficient is 1.
6. A NOx emission level regulating device, characterized in that the device comprises:
a NOx emission monitoring module for monitoring a NOx real-time emission level of a vehicle;
the engine monitoring module is used for monitoring the real-time rotating speed and the real-time torque of the engine of the vehicle;
the NOx emission calibration module is used for obtaining a corresponding NOx standard emission level according to the real-time rotating speed of the engine and the real-time torque of the engine;
the NOx emission control module is used for adjusting the fuel injection timing or EGR rate of the vehicle when the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level is larger than a first deviation threshold value, so that the real-time NOx deviation value between the real-time NOx emission level and the standard NOx emission level after response adjustment is smaller than a preset deviation permission threshold value; wherein the content of the first and second substances,
the corresponding relation exists between the adjusting value when the fuel injection timing is adjusted and the change value of the real-time NOx emission level;
and the adjustment value when the EGR rate is adjusted corresponds to the change value of the real-time NOx emission level.
7. The NOx emission level regulating device according to claim 6, wherein the device further comprises:
and the NOx emission warning module is used for forbidding to adjust the fuel injection timing or the EGR rate of the vehicle and carrying out NOx emission warning when the real-time NOx deviation value of the real-time NOx emission level and the standard NOx emission level is larger than a preset second deviation threshold value.
8. The NOx emission level regulating device according to claim 6, wherein:
the first deviation threshold corresponds to an engine load corresponding to the real-time engine speed.
9. The NOx emission level regulating device according to claim 6, wherein:
the NOx emission regulation and control module is further used for obtaining a first regulation weight coefficient and a second regulation weight coefficient based on the real-time rotating speed of the engine and the corresponding engine load;
the NOx emission control module is further used for adjusting the fuel injection timing or the EGR rate of the vehicle based on the first adjusting weight coefficient and the second adjusting weight coefficient; wherein the content of the first and second substances,
the first adjustment weight coefficient corresponds to the injection timing, and the second adjustment weight coefficient corresponds to the EGR rate.
10. The NOx emission level regulating device according to claim 9, wherein:
the maximum value of the first adjusting weight coefficient and the second adjusting weight coefficient is 1, the minimum value of the first adjusting weight coefficient and the second adjusting weight coefficient is 0, and the sum of the first adjusting weight coefficient and the second adjusting weight coefficient is 1.
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