CN107269408B - Diesel engine optimized combustion controller and simulation model control method - Google Patents
Diesel engine optimized combustion controller and simulation model control method Download PDFInfo
- Publication number
- CN107269408B CN107269408B CN201710338848.9A CN201710338848A CN107269408B CN 107269408 B CN107269408 B CN 107269408B CN 201710338848 A CN201710338848 A CN 201710338848A CN 107269408 B CN107269408 B CN 107269408B
- Authority
- CN
- China
- Prior art keywords
- output
- diesel engine
- time
- input
- formula
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000004088 simulation Methods 0.000 title description 18
- 239000000446 fuel Substances 0.000 claims abstract description 69
- 238000002347 injection Methods 0.000 claims abstract description 45
- 239000007924 injection Substances 0.000 claims abstract description 45
- 239000011159 matrix material Substances 0.000 claims abstract description 22
- 230000005284 excitation Effects 0.000 claims abstract description 10
- 238000005457 optimization Methods 0.000 claims abstract description 10
- 239000000243 solution Substances 0.000 claims abstract description 5
- 230000008859 change Effects 0.000 claims description 6
- 230000004044 response Effects 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 claims description 2
- 238000013461 design Methods 0.000 abstract description 4
- 230000007246 mechanism Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 5
- 238000004422 calculation algorithm Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000003912 environmental pollution Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000010200 validation analysis Methods 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011217 control strategy Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005094 computer simulation Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000013100 final test Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D37/00—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
- F02B37/12—Control of the pumps
- F02B37/24—Control of the pumps by using pumps or turbines with adjustable guide vanes
-
- 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]
-
- 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
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
- F02D41/1406—Introducing closed-loop corrections characterised by the control or regulation method with use of a optimisation method, e.g. iteration
-
- 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
-
- 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
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B23/00—Testing or monitoring of control systems or parts thereof
- G05B23/02—Electric testing or monitoring
- G05B23/0205—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults
- G05B23/0218—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterised by the fault detection method dealing with either existing or incipient faults
- G05B23/0243—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterised by the fault detection method dealing with either existing or incipient faults model based detection method, e.g. first-principles knowledge model
-
- 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
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
- F02D2041/1412—Introducing closed-loop corrections characterised by the control or regulation method using a predictive controller
-
- 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
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
- F02D2041/1433—Introducing closed-loop corrections characterised by the control or regulation method using a model or simulation of the system
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/02—Input parameters for engine control the parameters being related to the engine
- F02D2200/06—Fuel or fuel supply system parameters
- F02D2200/0625—Fuel consumption, e.g. measured in fuel liters per 100 kms or miles per gallon
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/02—Input parameters for engine control the parameters being related to the engine
- F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
- F02D2200/1002—Output torque
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
An optimized combustion controller for a diesel engine belongs to the technical field of diesel engines. The invention aims to control the fuel injection quantity, the fuel injection time, the opening degree of an EGR valve and the VGT sectional area of a diesel engine, so that the NOx emission of the diesel engine meets the national IV emission standard, and meanwhile, the diesel engine optimized combustion controller has good dynamic property and fuel economy performance. The method comprises the following steps: excitation data is selected, a system incremental prediction output equation is constructed through an input and output Hankel matrix, an incremental prediction matrix is obtained, and a data drive prediction controller is designed. The invention uses the input and output data of the system to identify off-line to obtain a control-oriented model of the system, which greatly reduces the time of traditional mechanism modeling; meanwhile, the identified control-oriented model has a linear structure, so that the design of the MPC controller and the online solution of the optimization problem of the MPC controller are facilitated.
Description
Technical Field
The invention belongs to the technical field of diesel engines.
Background
With the rapid development of the automotive industry, the number of automobiles worldwide is also increasing dramatically, with global automobile holdings exceeding 11 billion in 2015 and projected growth to 35 billion in 2050. Such a large number of cars will consume more than 10 billion tons of fuel per year, exceeding 1/3 of world annual oil production. At present rates of production, global oil resources will be depleted after 50 years, and the U.S. department of energy research predicts that a net gap will occur between global oil demand and regular oil supply after 2020. The energy crisis is at hand. Along with the use of fuel, the exhaust gas discharged from automobiles causes serious environmental pollution and endangers human health. The haze problem in most areas of China has aroused high attention of people [2] . Energy shortage, environmental pollution and climate warming are huge challenges facing the current automotive and energy industries in common. Aiming at the production and sale of automobiles, China has developed the latest national V emission standard, and the emission of automobiles is more strictly limited. Optimized combustion control for diesel enginesThe diesel engine can effectively reduce the emission of the diesel engine and effectively improve the economic performance and the power performance of the diesel engine, which has important significance for relieving the environmental pollution problem and the resource exhaustion problem in China.
Disclosure of Invention
The invention aims to control the fuel injection quantity, the fuel injection time, the opening degree of an EGR valve and the VGT sectional area of a diesel engine, so that the NOx emission of the diesel engine meets the national IV emission standard, and meanwhile, the diesel engine optimized combustion controller has good dynamic property and fuel economy performance.
The method comprises the following steps:
selection of excitation data: in a diesel engine combustion model, the designed fuel injection quantity, fuel injection time, the opening degree of an EGR valve and the rack position of a VGT are given to a diesel engine, and the model is operated in an open loop mode to obtain the actual NOx emission, the torque output by an engine crankshaft and the fuel consumption rate; obtaining input Hankel matrix of system according to the data
、
Output Hankel matrix
、
、
：
In formula (1)
Represents the output of the system at time 2 … N-2M + 2; in formula (3)
Represents the output of the system at time 2+ M … N-M + 2; wherein the system output at time i is
Wherein
、
、
Respectively representing the fuel consumption rate, the NOx emission amount and the crankshaft torque output by the diesel engine at the ith moment;
in the formula (2)
Represents the increment of the system output at the time 2 … … N-M +2, wherein the increment of the system output at the ith time is
I.e. the output of the system at time i minus the output at time i, wherein
、
、
Respectively representing the fuel consumption rate, the NOx emission amount and the crankshaft torque output by the diesel engine at the ith moment;
in the formula (4)
Represents the increment of system input at the time 2 … … N-M + 2; (5) in (1)
Represents the increment of the system input at the time 2+ M … N +2, wherein the increment of the system input at the ith time is
I.e. the output of the system at time i minus the output at time i, wherein
、
、
、
Respectively showing the fuel injection quantity, the opening degree of the EGR valve, the sectional area of the VGT and the fuel injection time at the ith moment;
secondly, constructing a prediction output equation of the system increment form through an input and output Hankel matrix, wherein the prediction output equation is as follows:
wherein
，
Inputting a Hankel matrix for the system;
the method is characterized in that two prediction matrixes in a prediction equation are obtained by solving a least square problem for a future output value of the system obtained by an incremental subspace identification method
And
：
wherein
Two prediction matrix coefficients
And
the solution of (d) is obtained by:
in the formula
And
are respectively as
And
transposing;
obtaining incremental prediction matrix
And
then, obtaining a future output value of the system by utilizing an incremental subspace prediction equation (6);
designing a data driving prediction controller: solving a quadratic programming problem corresponding to the objective function to obtain the optimized fuel injection quantity, fuel injection time, a rack position of the VGT and the opening degree of the EGR valve, wherein the mathematical expression of the objective function is shown as the formula (9):
wherein k is 1 、k 2 、k 3 、k 4 Is the weighting coefficient of the objective function, k and p are the current time and the prediction time domain, R T Output crankshaft torque, R, for a desired diesel engine NOx Calculated from the formula (10)
Wherein,
is front
Total NOx emissions at that time;
fifthly, replacing formula (6) with equivalent to obtain formula (11)
Where the F term is the free corresponding part of the system,
the items are referred to as control responses of the system;
by the formula (11), the objective function shown as follows is obtained:
wherein
Equation (13) describes the constraint on the rate of change of the control quantity, where
、
Maximum and minimum values of the control amount change rate, respectively, equation (14) describes the constraint on the control amount,
、
the maximum value and the minimum value of the controlled variable are respectively, and the optimal control rate can be obtained by solving the optimization problem (12) with constraints (13) and (14).
The invention can well solve the three problems in the prior art, can effectively model the system mechanism with complex surface based on the data-driven predictive control algorithm,
1. the input and output data of the system are used for identifying off line to obtain a control-oriented model of the system, so that the time of traditional mechanism modeling is greatly reduced; meanwhile, the identified control-oriented model has a linear structure, so that the design of the MPC controller and the online solution of the optimization problem of the MPC controller are facilitated.
2. The data-driven MPC controller can predict the future dynamics of the system and then make corresponding control according to the predicted system dynamics, so the influence of inertia on the output of the diesel engine can be well overcome by using the MPC controller, and the combustion process of the diesel engine is optimized.
3. The optimized combustion process of the diesel engine is a multi-input, multi-output and coupled multi-objective optimization problem. The data driven MPC controller has the capability to handle multi-objective optimization problems with coupling. The use of the data-driven MPC can simultaneously optimize the fuel economy, dynamics, and emissions performance of the diesel engine.
Drawings
FIG. 1 is a block diagram of the optimized combustion control of a diesel engine based on a data-driven MPC according to the present invention; the control quantity is the fuel injection quantity, the fuel injection time, the opening degree of an EGR valve and the sectional area of the VGT;
FIG. 2 is a schematic diagram of a GT model of a centralized diesel engine with EGR + VGT, which is composed of an environment setting module, a round tube module, a VGT module, an intercooler module, a three-way tube module, an EGR module, a four-cylinder 2-volume-increasing diesel engine module and an exhaust gas post-processing module according to the present invention;
FIG. 3 is a diesel engine optimized combustion data-driven MPC controller (1) built in Simulink of the present invention, which mainly implements a data-driven MPC control algorithm by an M file compiler in MATLAB;
FIG. 4 shows a diesel engine optimized combustion data-driven MPC controller (2) built in Simulink according to the present invention, which is mainly implemented by an M file compiler in MATLAB to realize a data-driven MPC control algorithm;
FIG. 5 is an input of fuel injection quantity in mg for each cycle with time on the abscissa in s for the diesel engine of the present invention;
FIG. 6 is an input of EGR valve opening when the present invention is energized for a diesel engine, with time on the abscissa and in units of s;
FIG. 7 is an input of injection delay angle in degrees (deg.) with time on the abscissa and in units of s when the diesel engine is energized in accordance with the present invention;
FIG. 8 is an input of VGT rack position when the diesel engine is energized according to the present invention, with time on the abscissa and units of s;
FIG. 9 is a graph of fuel consumption output in g/kwh plotted on the abscissa for time and in s for a diesel engine according to the present invention;
FIG. 10 is a graph of NOx emissions output in g/kwh on the abscissa and in s on the abscissa for a diesel engine according to the invention when energized;
FIG. 11 is crankshaft torque output in N.m, time on the abscissa and s, when the diesel engine is energized according to the present invention;
FIG. 12 is an input of fuel injection quantity in mg for each cycle, with time on the abscissa, in s, for validation of the identification model according to the present invention;
FIG. 13 is an input of EGR valve opening when the present invention verifies the identification model, with time on the abscissa and in units of s;
FIG. 14 is an input of fuel injection delay angle in degrees (°) with time on the abscissa and s, for validation of the identification model according to the present invention;
FIG. 15 is an input of VGT rack position when the present invention verifies the identification model, with the abscissa being time and the unit being s;
FIG. 16 is the output of the fuel consumption rate in g/kwh, abscissa time, and s, when the identification model is verified according to the present invention, wherein the solid line represents the output of the GT model and the dotted line represents the output of the identification model;
FIG. 17 is an output of NOx emissions in g/kwh with time on the abscissa and s on the basis of the verification of the identification model according to the present invention, wherein the solid line represents the output of the GT model and the dashed line represents the output of the identification model;
FIG. 18 is a graph of crankshaft torque output in N.m, time on the abscissa and s, for validation of the identification model of the present invention, where the solid line represents the output of the GT model and the dashed line represents the output of the identification model;
FIG. 19 is a graph of fuel injection quantity input in mg for each cycle of fuel injection, plotted on the abscissa for time and plotted in s, for controlling a diesel engine in a driving mode according to the present invention;
FIG. 20 is an input of EGR valve opening when the present invention is controlling a diesel engine in a driving mode, with time on the abscissa and in units of s;
FIG. 21 is an input of injection delay angle in degrees (°) with time on the abscissa and s for the present invention when controlling a diesel engine in a driving mode;
FIG. 22 is an input of VGT rack position when controlling a diesel engine in a driving mode according to the present invention, with the abscissa being time and the unit being s;
FIG. 23 is a graph of the output of specific fuel consumption in g/kwh plotted on the abscissa for time plotted in s, for controlling a diesel engine in a driving mode according to the present invention;
FIG. 24 is a graph of NOx emissions output in g/kwh on the abscissa versus time in s for a diesel engine controlled in a driving mode in accordance with the present invention;
FIG. 25 is crankshaft torque output in N.m, abscissa time and s, for the present invention controlling a diesel engine in a driving mode, where the solid line represents the output of the GT model and the dashed line represents the output of the identification model;
FIG. 26 is an input of fuel injection quantity in mg for each cycle with time on the abscissa for s, according to the invention in the load mode for controlling a diesel engine;
FIG. 27 is an input of EGR valve opening during control of a diesel engine in a load mode according to the present invention, plotted on the abscissa for time and expressed in units of s;
FIG. 28 is an input of injection delay angle in degrees (°) with time on the abscissa and s for the present invention in load mode control of a diesel engine;
FIG. 29 is a graph of VGT rack position input with time on the abscissa and units of s for the present invention in a load mode for diesel engine control;
FIG. 30 is a graph of fuel consumption output in g/kwh on the abscissa versus time in s for the present invention in load mode controlling a diesel engine;
FIG. 31 is a graph of NOx emissions output in g/kwh on the abscissa and time in s for the diesel engine controlled in the load mode according to the present invention;
fig. 32 is an output of the rotation speed of the diesel engine in rpm with time on the abscissa in units of s when the diesel engine is controlled in the load mode according to the present invention, in which a solid line represents the output of the GT model and a dotted line represents the output of the recognition model.
Detailed Description
The method includes the steps that firstly, corresponding control indexes are provided aiming at the economic performance, the power performance and the fuel economy of the diesel engine, and corresponding control input is selected; secondly, appropriate excitation data are designed according to the characteristics of the system so as to ensure sufficient excitation on the steady-state and dynamic characteristics of the system; secondly, selecting an input/output matrix with a proper size to identify the system according to the step response characteristic of the system; then, considering the constraint of the actuator, and constructing a corresponding cost function by using a model predictive control algorithm; and finally, solving the optimal problem corresponding to the objective function to obtain control input and applying the control input to the system, thereby realizing the control of the system.
The optimized combustion of the diesel engine based on the data-driven MPC controller is realized by the joint simulation of GT-power and Simulink. The GT-power is a commercial complex system modeling simulation platform, and a high-fidelity diesel engine combustion model is built by utilizing the GT-power and is used for replacing a real diesel engine in a simulation experiment; MATLAB/Simulink is used for building a simulation model of the controller, namely the building of the diesel engine optimized combustion controller based on the data-driven MPC is completed through Simulink programming.
Functionally, the present invention may include the following: the controller simulates a module and a diesel engine combustion model with EGR-VGT. The function of each part is explained in detail as follows:
the diesel engine combustion model with the EGR-VGT is mainly used for obtaining input and output excitation data capable of reflecting system characteristics through off-line simulation, and therefore a control-oriented model is obtained through a subspace identification method.
The control module is mainly used for collecting input and output of a diesel engine combustion model and then obtaining control signals (oil injection quantity, oil injection time, opening degree of an EGR valve and rack position of VGT) optimal to the system by solving corresponding quadratic programming problems;
the invention discloses a control block diagram of optimized combustion control of a diesel engine based on a data-driven MPC controller, which is shown in FIG. 1. The controller in the figure is built in Simulink, the input of the controller is the fuel injection quantity, the fuel injection time, the opening degree of an EGR valve and the position of a VGT rack, and the actual fuel consumption rate, the NOx emission and the torque output by a crankshaft of the engine are fed back to the controller in real time. Considering the actual existing constraint, the value range of the fuel injection amount is 0 mg-40 mg, the fuel injection time is-10, the value range corresponding to the opening degree of the EGR valve is 0-0.3, and the position range of the rack corresponding to the sectional area of the VGT is 0-1.
The control objective of the present invention is to track the crankshaft torque output by the diesel engine to a desired value while optimizing the specific fuel consumption and allowing the NOx emissions from the diesel engine to meet the five emissions standards of state.
According to the steps, the PC-based offline diesel engine optimized combustion design test platform can be obtained. The construction and operation processes of the platform are as follows:
first, simulation platform construction
A controlled object and a controller of the diesel engine optimized combustion control system are respectively built through MATLAB/Simulink and GT-power, and a solver selects ode 3 and Explicit-Runge-Kutta respectively. The simulation step length is a fixed step length, and is selected to be 0.04s in the invention.
Two, combined simulation setup
The joint simulation of MATLAB/Simulink and GT-power has two modes, one mode is to call the model in MATLAB/Simulink in GT-power; the other is the model calling GT-power in MATLAB/Simulink. In the invention, a second combined simulation mode is used for facilitating the debugging of the controller. To implement the joint simulation of MATLAB/Simulink and GT-power, the GT-power installation path is first added to MATLAB. And then adding corresponding communication interface modules on the GT-power interface and the MATLAB/Simulink interface respectively, and connecting variables needing communication between the MATLAB/Simulink and the GT-power to the modules. And finally, setting a simulation step size in MATLAB/simulink, wherein the simulation step size in the process of carrying out the joint simulation is necessarily set as a fixed step size.
Thirdly, building a simulation model of the combustion process of the centralized diesel engine: by adopting a modularized method, a diesel engine model with EGR-VGT is built in GT-power, and a schematic diagram is shown in FIG. 2. The model consists of an environment setting module, a circular tube module, a VGT module, an intercooler module, a three-way tube module, an EGR module, a four-cylinder 2-liter-displacement diesel engine module and a tail gas aftertreatment module. Firstly, a file is newly built in the GT, then an environment setting module 1 (EndEnvironment) is pulled into the file, and the environment temperature and pressure are set through the module, wherein the specific parameters are shown in Table 1, wherein a Composition attribute and a Humidity Specifications attribute respectively use an air object and an h2o-vap object carried by the GT; then the environment setting module and the environment setting module are connected with the compressor module through a circular tube module 1, wherein the parameters of the circular tube module 1 are shown in table 1; then connecting the compression and an intercooler together, wherein the parameter of the intercooler directly uses the parameter in the demo; then an intercooler, an inlet of a diesel engine module discharged by four cylinders 2L and an outlet of an EGR module are connected together through a three-way pipe 1, wherein parameters of the diesel engine module discharged by the four cylinders 2L are shown in a table 1, other parameters directly use demo self-contained parameters, and parameters of the three-way pipe 1 are shown in the table 1; then the outlets of the diesel engine module, the turbine and the inlet of the EGR module which are discharged from the four cylinders 2L are connected together through a three-way pipe module 2, and the parameters of the three-way pipe module 2 are shown in the table 1; then the turbine is connected with the exhaust gas after-treatment system through the circular pipe module 2, the parameters of the exhaust gas after-treatment system directly use the demo parameters, the parameters of the circular pipe module 2 are shown in table 1, and finally the exhaust gas after-treatment module is connected with the environment setting module 2 through the circular pipe module 3, wherein the parameters of the circular pipe module 3 are shown in table 1, and the parameters of the environment facility module 2 are consistent with the parameters of the environment setting module 1.
TABLE 1 list of parameters for diesel engines with EGR + VGT
Optimized combustion control scheme for diesel engine
First is the determination of the control target: the average value of the NOx emission is smaller than 2g/kwh so as to meet the requirement of the national five-emission standard on the NOx emission; meanwhile, the crankshaft torque output by the diesel engine is tracked to an expected value so as to meet the requirement on the dynamic property of the diesel engine; and finally, on the premise of meeting the emission performance and the power performance, the fuel consumption is reduced as much as possible.
Determination of control amount: for a diesel engine, the output torque of the diesel engine is mainly determined by the fuel injection quantity; in order to improve the fuel economy and the dynamic property of the diesel engine, the fuel injection time of the diesel engine and the section of the VGT need to be optimized; on the other hand, in order to reduce the NOx emission of the diesel engine, it is necessary to control the opening degree of the EGR valve, and therefore, in order to satisfy the above control target, the present invention selects the fuel injection amount, the fuel injection timing, the EGR rate, and the sectional area of the VGT as control amounts.
Selection of the controller: because the combustion process of the diesel engine is complex and has strong nonlinearity, the method uses an incremental sub-space identification method to build a model facing control; on the other hand, the invention uses an incremental data-driven MPC controller, considering that the MPC controller can solve the band constraint and multi-objective optimization problem well.
After the control target, the control quantity and the controller are determined, the diesel engine optimized combustion control scheme can be obtained, and a specific control block diagram is shown in fig. 1.
Optimized combustion data driving prediction controller for diesel engine
Selection of excitation data: selecting the fuel injection quantity, the fuel injection time, the opening degree of an EGR valve and the rack position of a VGT (in a GT model, the sectional area of the VGT is determined by the rack position, and the position of the rack changes in the range of 0-1) of the diesel engine as excitation input signals, and in a GT-power diesel engine combustion model, giving the designed fuel injection quantity, the fuel injection time, the opening degree of the EGR valve and the rack position of the VGT to the diesel engine, and performing open-loop operation on the model to obtain the actual NOx emission, the torque output by an engine crankshaft and the fuel consumption rate; obtaining input Hankel matrix of system according to the data
、
Output Hankel matrix
、
、
：
In formula (1)
Represents the output of the system at time 2 … N-2M + 2; in formula (3)
Indicating the system output at time 2+ M … N-M +2Discharging; because the output in equation (3) is the value of the system at the future time M, the output in equation (3) leads the corresponding output in equation (1) at time M. Wherein the system output at time i is
Wherein
、
、
The fuel consumption rate, the NOx emission amount, and the crankshaft torque output from the diesel engine at the i-th time are respectively indicated.
In the formula (2)
Represents the increment of the system output at the time 2 … … N-M + 2, wherein the increment of the system output at the ith time is
I.e. the output of the system at time i minus the output at time i, wherein
、
、
Respectively representing the fuel consumption rate, the NOx emission amount and the crankshaft torque output by the diesel engine at the ith moment;
in the formula (4)
Represents the increment of the system input at the time 2 … … N-M + 2; (5) In (1)
Represents the increment of the system input at the time 2+ M … N +2, wherein the increment of the system input at the ith time is
I.e. the output of the system at time i minus the output at time i, wherein
、
、
、
Respectively showing the fuel injection quantity, the opening degree of the EGR valve, the sectional area of the VGT and the fuel injection time at the ith moment;
constructing a prediction output equation of a system increment form through an input and output Hankel matrix, wherein the prediction output equation comprises the following components:
wherein
，
Inputting a Hankel matrix for the system;
the method is characterized in that two prediction matrixes in a prediction equation are obtained by solving a least square problem for a future output value of the system obtained by an incremental subspace identification method
And
：
wherein
Two prediction matrix coefficients
And
the solution of (d) is obtained by:
in the formula
And
are respectively as
And
the transposing of (1).
Obtaining incremental prediction matrix
And
then, obtaining a future output value of the system by utilizing an incremental subspace prediction equation (6); after obtaining the prediction equation shown in (6), the present invention verifies the accuracy of the recognition model using the excitation input shown in fig. 5, and the verification result is shown in fig. 7. As can be seen from fig. 7, the predicted system output matches the actual value well.
Designing a data driving prediction controller: solving a quadratic programming problem corresponding to the objective function to obtain the optimized fuel injection quantity, fuel injection time, a rack position of the VGT and the opening degree of the EGR valve, wherein the mathematical expression of the objective function is shown as the formula (9):
wherein k is 1 、k 2 、k 3 、k 4 Is the weighting coefficient of the objective function, k and p are the current time and the prediction time domain, R T Output crankshaft torque, R, for a desired diesel engine NOx Calculated by equation (10) and obtained by equation (9), the objective function includes: tracking of diesel engine output crankshaft torque, optimization of fuel consumption and
and (4) tracking and optimizing the emission.
Wherein,
is front
Total NOx emissions at that time;the physical significance of equation 10 is such that the average of the NOx emissions will be equal to (1.95 g/kwh) over the foreseeable future 100 moments.
For the convenience of derivation of the controller, the formula (6) is replaced by the same amount to obtain the formula (11)
Where the F term is the free corresponding part of the system,
the items are referred to as control responses of the system.
By the formula (11), the objective function shown as follows is obtained:
wherein
equation (13) describes the constraint on the rate of change of the control quantity, where
、
Respectively a maximum value and a minimum value of the control amount change rate,
are respectively 40, 0.3, 10, 1, -40, -0.3, -10, -1. Equation (14) describes the constraint on the control quantity,
、
respectively a maximum value and a minimum value of the control quantity,
are 40, 0.3, 10, 1, 0, -10, 0, respectively. By solving the optimization problem (12) with constraints (13), (14), an optimal control rate can be obtained. As shown in fig. 3.
Experimental verification
The control performance of model predictive control depends on the accuracy of the predictive model. In order to verify the accuracy of the model, the invention redesigns a set of excitation inputs as shown in fig. 11, 12, 13 and 14, and the experimental results are shown in fig. 15, 16 and 17. As can be seen from fig. 15, 16, and 17, the NOx, the fuel consumption rate, and the crankshaft torque output of the prediction model can be well tracked to the actual system output values.
In order to further verify the control performance of the diesel engine optimized combustion data driven MPC controller, the invention uses FTP75 working condition to carry out simulation experiment on the control performance of the controller under a dynamometer mode and a driving mode respectively. The FTP75 condition is referred to as the most reasonable cyclic condition test rule at present, where the united states california has played a critical role. Based on the principle of testing the truest data, the working condition of the American FTP75 designs a lot of experimental contents close to reality. The FTP75 is composed of an urban circulation condition and two supplementary circulation conditions. The two supplementary circulation working conditions are SC03 high-temperature air conditioner full-load operation circulation and US06 high-speed and high-acceleration circulation respectively. The final test results are calculated from the three test results by different ratios, so that such data are closer to actual use.
1. Dynamometer mode
The dynamometer mode in GT calculates the corresponding torque output from the rotational speed of the diesel engine and the input to the diesel engine. The invention uses the diesel engine speed under the FTP75 condition as a given input to verify the performance of the data-driven MPC controller under complex conditions, and the experimental results are shown in FIGS. 22, 23 and 24, and the optimal control quantity is shown in FIGS. 18, 19, 20 and 21. As can be seen from fig. 24, the actual output of the crankshaft torque of the diesel engine can be well tracked to the expected value; meanwhile, the average emission amount of NOx is 1.9152g/kwh, which can meet the requirement of the national five-emission standard on NOx emission; the average fuel consumption was 262.4231 g/kwh. At this time, the invention considers that the diesel engine optimized combustion control strategy based on the data-driven MPC under the dynamometer mode can simultaneously improve the power performance, the economic performance and the emission performance of the diesel engine.
2. Driving mode
The driving mode in GT is to calculate the speed of the diesel engine from the load torque input by the diesel engine and the input of the diesel engine. The rotation speed of the diesel engine in the GT can be obtained by the following equation (15).
Wherein,
is the angular acceleration of the diesel engine, which can be derived from the desired rotational speed of the diesel engine; j is the rotational inertia of the diesel engine;
crankshaft torque for diesel engine output;
the load torque input by the diesel engine. In the experimental process, the load torque of the diesel engine is a constant value which is considered to be given; the expected diesel engine speed is the diesel engine speed under the FTP75 working condition; the experimental results are shown in fig. 29, 30 and 31, and the optimal control inputs are shown in fig. 25, 26, 27 and 28.
Fig. 31 shows that the diesel engine can well track the expected diesel engine speed in the driving mode;
meanwhile, the average value of the NOx emission is 1.9225g/kwh which can meet the requirement of the national five-emission standard on the NOx emission according to the graph 30; from FIG. 29, the average value of the fuel consumption was 262.1950 g/kwh. At this time, the invention considers that the diesel engine optimized combustion control strategy based on the data-driven MPC in the driving mode can simultaneously improve the power performance, the economic performance and the emission performance of the diesel engine.
The present invention uses a data-driven MPC based controller to control the combustion process of a four cylinder 2L-emitting diesel engine. Firstly, a control-oriented model is obtained by using the input and output data of the system for off-line identification, and the precision of the model is verified through experiments, so that the time for modeling by a traditional mechanism is reduced, and the precision of the model is improved; then, an MPC controller is designed by using the prediction model, and the controller can generate a control rate according to the dynamic advance of a future system of the system, so that the influence of inertia on the output of the diesel engine can be well overcome; on the other hand, the controller can process multi-input, multi-output and multi-target optimization problems with coupling, so that the fuel economy, the dynamic property and the emission performance of the diesel engine can be unified into one target function, and the fuel economy, the dynamic property and the emission performance of the diesel engine are optimized.
Claims (1)
1. An optimized combustion controller for a diesel engine, comprising:
selection of excitation data: in a diesel engine combustion model, the designed fuel injection quantity, fuel injection time, the opening degree of an EGR valve and the rack position of a VGT are given to a diesel engine, and the model is operated in an open loop mode to obtain the actual NOx emission, the torque output by an engine crankshaft and the fuel consumption rate; obtaining input Hankel matrix delta I of the system according to the data p 、ΔI f Output Hankel matrix O p 、O f 、ΔO p ：
O in the formula (1) 2 ,…,O N-2M+2 Represents the system output of the system at the time of 2, …, N-2M + 2; o in the formula (3) 2+M ,…,O N-M+2 Representing the system output of the system at time 2+ M, …, N-M + 2; wherein the system output at time i is
Wherein
Respectively representing the fuel consumption rate, the NOx emission amount and the crankshaft torque output by the diesel engine at the ith moment;
delta O in the formula (2) 2 .....ΔO N-M+2 Represents the increment of the system output at the time 2 … … N-M +2, wherein the increment of the system output at the ith time is
I.e. the output of the system at time i-1 minus the output at time i, where
Respectively representing the fuel consumption rate, the NOx emission amount and the crankshaft torque output by the diesel engine at the ith moment;
delta I in the formula (4) 2 ,…,ΔI N-2M+2 Represents the increment of the system input at the time 2, …, N-2M + 2; delta I in the formula (5) 2+M ,…,ΔI N-M+2 Represents the increment of the system input at the time of 2+ M, …, N-M +2, wherein the increment of the system input at the ith time is
I.e. the input of the system at the i-1 th moment minus the input at the i-th moment, wherein
Respectively showing the fuel injection quantity, the opening degree of the EGR valve, the sectional area of the VGT and the fuel injection time at the ith moment;
secondly, constructing a prediction output equation of the system increment form through an input and output Hankel matrix, wherein the prediction output equation is as follows:
wherein
ΔW p Is Δ I p And Δ O p New matrix of composition, Δ I f For the input Hankel matrix of the system,
namely obtaining the future output value of the system by the incremental subspace identification method, and obtaining two prediction matrixes delta L in the prediction equation by solving the least square problem w And Δ L u ：
Wherein Δ O f ＝O f -O p Two prediction matrix coefficients Δ L w And Δ L u The solution of (d) is obtained by:
in the formula
And
are respectively W p And I f Transpose of (W) p Is I p And O p The new matrix of the composition is then formed,
obtaining two incremental prediction coefficient matrixes delta L w And Δ L u Then, incremental subspaces are utilizedPredicting an equation (6) to obtain a future output value of the system;
designing a data driving prediction controller: solving a quadratic programming problem corresponding to the objective function to obtain the optimized fuel injection quantity, fuel injection time, a rack position of the VGT and the opening degree of the EGR valve, wherein the mathematical expression of the objective function is shown as the formula (9):
wherein k is 1 、k 2 、k 3 、k 4 Is the weighting coefficient of the objective function, k and p are the current time and the prediction time domain, R T Output crankshaft torque, R, for a desired diesel engine NOx Calculated by formula (10), J represents the objective function;
wherein, Sum NOx Total NOx emissions at time i;
fifthly, replacing formula (6) with equivalent to obtain formula (11)
Where the F term is the free corresponding part of the system, S.DELTA.I f The items are referred to as control responses of the system;
by the formula (11), the objective function shown as follows is obtained:
wherein
A is a weighting coefficient and a is a weight coefficient,
the input constraints of the system are described by equations (13), (14):
equation (13) describes the constraint on the rate of change of the control quantity, where δ I max 、δI min Maximum and minimum values of the rate of change of the controlled variable, respectively, and equation (14) describes the constraint on the controlled variable, I max 、I min The maximum value and the minimum value of the controlled variable are respectively, and the optimal control rate can be obtained by solving the optimization problem (12) with constraints (13) and (14).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710338848.9A CN107269408B (en) | 2017-05-15 | 2017-05-15 | Diesel engine optimized combustion controller and simulation model control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710338848.9A CN107269408B (en) | 2017-05-15 | 2017-05-15 | Diesel engine optimized combustion controller and simulation model control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107269408A CN107269408A (en) | 2017-10-20 |
| CN107269408B true CN107269408B (en) | 2022-08-05 |
Family
ID=60063977
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710338848.9A Active CN107269408B (en) | 2017-05-15 | 2017-05-15 | Diesel engine optimized combustion controller and simulation model control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107269408B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110329258B (en) * | 2019-07-23 | 2021-04-30 | 吉林大学 | Intelligent driving automobile energy-saving emission-reducing coordination control method |
| CN113448318B (en) * | 2021-07-07 | 2022-08-16 | 江铃汽车股份有限公司 | Vehicle offline fault diagnosis control method |
| CN115390443A (en) * | 2022-05-18 | 2022-11-25 | 北京理工大学 | Data-driven self-triggering control method for unknown system |
| CN114934848B (en) * | 2022-06-16 | 2023-04-07 | 哈尔滨工程大学 | Fuzzy neural network modeling method for optimizing control of combustion performance of diesel engine |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102588129A (en) * | 2012-02-07 | 2012-07-18 | 上海艾铭思汽车控制系统有限公司 | Optimization cooperative control method for discharge of nitrogen oxides and particles of high-pressure common-rail diesel |
| CN105629736A (en) * | 2016-03-22 | 2016-06-01 | 东南大学 | Data-driven thermal power generation unit SCR denitration disturbance suppression prediction control method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3383874B2 (en) * | 1993-07-19 | 2003-03-10 | 克享 小西 | Diesel engine combustion simulation method |
| DE10020448B4 (en) * | 2000-04-26 | 2005-05-04 | Daimlerchrysler Ag | Method and device for optimizing the operation of an internal combustion engine |
| US7184877B1 (en) * | 2005-09-29 | 2007-02-27 | International Engine Intellectual Property Company, Llc | Model-based controller for auto-ignition optimization in a diesel engine |
| DE102006061936A1 (en) * | 2006-12-29 | 2008-07-03 | Robert Bosch Gmbh | Internal combustion engine's operation simulating method for motor vehicle, involves using model for simulation of operation of engine by considering control parameters and component parameter characterizing operation of components |
| CN104401232B (en) * | 2014-12-21 | 2016-06-22 | 吉林大学 | Electric automobile torque optimization method based on data-driven PREDICTIVE CONTROL |
| CN105221275B (en) * | 2015-08-20 | 2017-10-13 | 吉林大学 | Turbocharged Gasoline Engine control system based on Model Distinguish |
-
2017
- 2017-05-15 CN CN201710338848.9A patent/CN107269408B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102588129A (en) * | 2012-02-07 | 2012-07-18 | 上海艾铭思汽车控制系统有限公司 | Optimization cooperative control method for discharge of nitrogen oxides and particles of high-pressure common-rail diesel |
| CN105629736A (en) * | 2016-03-22 | 2016-06-01 | 东南大学 | Data-driven thermal power generation unit SCR denitration disturbance suppression prediction control method |
Non-Patent Citations (1)
| Title |
|---|
| 高炉热风炉燃烧输入输出数学模型的应用;丁洪起等;《钢铁》;20160315(第03期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107269408A (en) | 2017-10-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107269408B (en) | Diesel engine optimized combustion controller and simulation model control method | |
| Jankovic et al. | Robust nonlinear controller for turbocharged diesel engines | |
| Xu et al. | Digital twin-driven optimization of gas exchange system of 2-stroke heavy fuel aircraft engine | |
| Dong et al. | Experiment and simulation investigation on energy management of a gasoline vehicle and hybrid turbocharger optimization based on equivalent consumption minimization strategy | |
| Norouzi et al. | Deep learning based model predictive control for compression ignition engines | |
| CN104408271A (en) | Model-based gasoline engine calibration method | |
| Yin et al. | Model predictive control of an advanced multiple cylinder engine with partially premixed combustion concept | |
| Nikzadfar et al. | Investigating a new model-based calibration procedure for optimizing the emissions and performance of a turbocharged diesel engine | |
| CN111608790B (en) | Gas circuit optimization control system of electric auxiliary turbocharged diesel engine | |
| Isermann et al. | Mechatronic combustion engines–from modeling to optinlal control | |
| Chiara et al. | An exhaust manifold pressure estimator for a two-stage turbocharged diesel engine | |
| Sakai et al. | Torque demand control by nonlinear MPC with constraints for vehicles with variable valve lift engine | |
| Wang et al. | Adaptive air-fuel ratio control with MLP network | |
| Ke et al. | Neural network based nonlinear model predictive control for two-stage turbocharged diesel engine air-path system | |
| Duraiarasan et al. | Real-time embedded models for simulation and control of clean and fuel-efficient heavy-duty diesel engines | |
| Keller et al. | Physics-based modeling and mpc for the air path of a two-stage turbocharged si engine with low pressure egr | |
| Li et al. | Air path system control of turbocharged gasoline engine based on fuzzy PID | |
| Norouzi et al. | Integration of Deep Learning and Nonlinear Model Predictive Control in Emission reduction of Compression Ignition Combustion Engines: A Simulative Study | |
| Kuzmych et al. | Nonlinear control for a diesel engine: A CLF-based approach | |
| Zhang et al. | Method of Turbocharger Emulation on Engine Test and Application to Turbocompound System Optimisation | |
| Sun et al. | Integrated control of torque and emission of a diesel engine based on LPV‐MPC | |
| Topaloglou et al. | Transient load share management of a diesel electric hybrid powertrain for ship propulsion | |
| Lorini et al. | Modelling, simulation and predictive control of a spark ignition engine | |
| Youssef et al. | Model based control of turbochargers: Application to a Diesel HCCI engine | |
| Cieslar et al. | Model based control for closed loop testing of 1-D engine simulation models |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |