An engine twin model modeling system and a modeling method
By using an engine twin model system, combined with physical prototypes and servers, real-time simulation and online optimization of engineering machinery engines have been achieved. This solves the problems of high computational load and insufficient accuracy in existing technologies, and improves the flexibility of engine control strategies and the operational performance of engineering machinery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUNWARD INTELLIGENT EQUIP CO LTD
- Filing Date
- 2023-05-16
- Publication Date
- 2026-05-08
AI Technical Summary
In existing technologies, the performance simulation of engineering machinery engines involves large computational loads and long processing times, cannot achieve twin processes, traditional models have insufficient verification accuracy, and engine control strategies cannot be optimized online.
An engine twin model system combining a physical prototype and a server is used to collect parameters in real time through various sensors and data acquisition devices. The system utilizes hardware-in-the-loop software to realize real-time simulation and verification of the engine twin model, including parameter input, output and solution modules, to achieve performance simulation and control strategy optimization throughout the entire life cycle.
It enables real-time simulation and online optimization of engines, improving simulation accuracy and efficiency, supporting parameter analysis and fault diagnosis throughout the engine's entire life cycle, and enhancing the operational performance and energy-saving and emission-reduction capabilities of construction machinery.
Smart Images
Figure CN116627050B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of engineering machinery, and in particular to an engine twin modeling system and modeling method. Background Technology
[0002] Construction machinery plays a vital role in road construction, large-scale engineering construction and maintenance, national defense construction, and energy development. In recent years, the intelligentization and digitalization of construction machinery have developed rapidly. Various products have been developed in the construction machinery field, such as intelligent excavators, rotary drilling rigs, and loaders. Simulation technology is the most widely used technology in the research, design, production, and use of construction machinery products. Based on the scale of simulation, it can be divided into cloud computing simulation, ordinary computer simulation, and edge computing simulation; based on the application field, it can be divided into structural simulation, motion simulation, control strategy simulation, and performance simulation. Cloud computing simulation has been a research hotspot in recent years, as its use relies on system infrastructure and applications. Ordinary computer simulation has been the most widely used simulation technology in recent decades, playing a vital role in various fields. It typically features complex simulation models, long computation times, and high accuracy. Edge computing is a new simulation method that combines online simulation in recent years. While it has limited computing power and high development costs, its key feature is real-time simulation capabilities.
[0003] In 2002, Professor Michael of the University of Michigan proposed the concept of digital twins based on product lifecycle management. In 2010, the U.S. Department of Defense first used digital twin technology for the health maintenance and support of aerospace vehicles. In 2017, the Digital Twin Research Group of Beijing University of Aeronautics and Astronautics published the first article on digital twins in China. Because digital twins can empower the implementation of technologies and concepts such as intelligent manufacturing, Industry 4.0, the Industrial Internet, smart cities, and airport operations, they have attracted attention from universities, enterprises, research institutes, and other industries, becoming a hot research topic in recent years. With the continuous promotion of digital twin technology applications, it is expected to be applied and promoted in engineering machinery products, achieving energy conservation and emission reduction through information-based, data-driven, and intelligent management.
[0004] However, the main problems with the current performance simulation of construction machinery engines are as follows:
[0005] (1) At present, most of the performance simulations of engines are numerical solution methods such as finite element method, finite difference method, and finite volume method. These methods are computationally intensive and time-consuming, and cannot realize the twin process. It can be seen that the modeling method of digital twin model of engine in construction machinery is immature.
[0006] (2) The traditional engine simulation model verification process only verifies a portion of the operating conditions once, and the accuracy of the model cannot be guaranteed after changes in operating conditions or boundary conditions. Digital twin models require calibration across the entire operating range, and even as the service life increases, the engine model needs to be recalibrated;
[0007] (3) The parameter control of traditional engineering machinery engines relies on calibration. After calibration, the parameter control strategy in the engine ECU cannot be modified. However, digital twins require that the engine control strategy can be optimized throughout its entire life cycle.
[0008] Based on this, the present invention provides an engine twin modeling system and modeling method. Summary of the Invention
[0009] This invention addresses the shortcomings of existing technologies by providing an engine twin modeling system and method.
[0010] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:
[0011] In a first aspect, the present invention provides an engine twin modeling system.
[0012] An engine twin modeling system includes a physical prototype, a server, and an engine twin model;
[0013] The physical prototype is a rotary drilling rig and its diesel engine;
[0014] The rotary drilling rig is equipped with various sensors, controllers, data acquisition devices, data transmitters, and data receivers, among which:
[0015] The data acquisition device collects parameters from the physical prototype. Some parameters are collected directly from the CAN bus, while others are collected directly from the sensors.
[0016] The server is used to interact with data on the physical prototype in real time, and the server has a running environment for the engine twin model;
[0017] The engine twin model is a virtual twin of the actual engine, running in real time along with the actual engine. The time for the engine twin model to calculate one working cycle is less than the actual working cycle time of the engine.
[0018] The engine twin model includes a parameter input module, a parameter output module, and a solution module, wherein:
[0019] The parameter input module has data analysis and data processing capabilities. The parameter input module is used to input the initial data of the engine twin model. The initial data are parameters collected from the physical prototype, including engine speed, intake pressure, temperature, exhaust temperature, pressure, excess air coefficient, and pollutant measurement.
[0020] The parameter output module is used to output the engine performance parameters obtained from the engine twin model simulation, and to display and store the data;
[0021] The solution module includes a ventilation process simulation module, an exhaust waste heat energy simulation module, an emission parameter simulation module, a heat transfer process simulation module, a heat-work conversion process simulation module, a mechanical loss simulation module, and a performance parameter simulation module, wherein:
[0022] The ventilation process simulation module is used to calculate the fresh air intake flow rate and EGR flow rate based on the intake pressure, temperature, speed, and throttle opening, and to calculate the total fuel energy based on the fuel flow rate.
[0023] The exhaust waste heat energy simulation module is used to calculate the exhaust waste heat energy and the proportion of waste heat energy based on exhaust temperature and flow rate.
[0024] The emission parameter simulation module is used to calculate the specific emission and combustion efficiency based on the intake air volume, fuel injection volume, and pollutant volume emission volume.
[0025] The heat transfer process simulation module is used to calculate heat dissipation from the cooling system, lubricating oil, cylinder, and system heat storage.
[0026] The heat-work conversion process simulation module is used to obtain engine indicated performance parameters;
[0027] The mechanical loss simulation module is used to calculate the amount of mechanical loss based on engine speed and throttle opening.
[0028] The performance parameter simulation module is used to calculate engine power performance parameters based on engine speed and torque ratio, and to calculate economic performance parameters based on fuel quantity and engine operating conditions.
[0029] Furthermore, parameters collected from the CAN bus include engine speed, fuel injection quantity, torque percentage, intake pressure, and temperature; parameters collected from sensors include exhaust pressure, temperature, excess air coefficient, and contaminants.
[0030] Furthermore, the sensors include an engine speed sensor, an intake air pressure sensor, a temperature sensor, an exhaust temperature sensor, a pressure sensor, an exhaust oxygen sensor, and a pollutant measurement sensor.
[0031] Furthermore, the controller includes a master controller and a slave controller. The master controller is responsible for processing signals from sensors, displays, and switch components. The slave controller is connected to the actuator via a CAN bus and receives signals from engine, hydraulic, and fuselage position sensors via the CAN bus.
[0032] Furthermore, the data transmitter sends data to the Internet via 5G signals, and the server directly reads the Ethernet data sent by the data transmitter.
[0033] Furthermore, the data receiver receives 5G signal data and transmits the signal to the actuator to control the construction of the physical prototype.
[0034] Secondly, the present invention provides a method for modeling an engine twin model.
[0035] An engine twin modeling method, applied to the aforementioned modeling system, includes the following steps:
[0036] S1: Real-time acquisition of key parameters of the physical prototype through multiple sensors and CAN bus;
[0037] S2: Transient data preprocessing of physical prototype;
[0038] S3: Run an engine twin model that can achieve digital twin;
[0039] S4: Adaptive control to complete the physical prototype simulation process;
[0040] S5: Complete the physical prototype status assessment and control strategy feedback.
[0041] Furthermore, step S2 specifically includes:
[0042] S2.1: Convert the data based on engine time to data based on engine cycle, where one engine working cycle corresponds to one set of collected data. Calculate the time t required for one engine working cycle using the following formula:
[0043]
[0044] In the formula, n is the engine speed, and δ is related to the engine stroke. When the engine stroke is four-stroke, δ is 2, and when the engine stroke is two-stroke, δ is 1. If more than one data point is collected for a certain parameter within a time period, these data points are averaged to reduce the amount of data. If it takes several times longer to collect a data point for a certain parameter, the two collected data points are interpolated to ensure that each time point corresponds to one data point, thus filling in the data gaps. After the above processing, each engine working cycle corresponds to one value, one time, and one number for each parameter.
[0045] S2.2: Complete the display of key engine parameters and the preprocessing of initial engine model data.
[0046] Furthermore, step S3 specifically includes:
[0047] S3.1: The parameters including intake airflow, volumetric efficiency, and EGR flow are calculated using the scavenging process simulation module. The actual intake airflow of the engine is calculated as follows:
[0048]
[0049] In the formula, It's the air intake flow rate. It is the pressure after the compressor. It is the engine charge coefficient. It refers to engine displacement. It refers to the number of engine cylinders. It is the gas constant of air. This refers to the intake manifold temperature, where the volumetric efficiency is calculated as follows:
[0050]
[0051] Let be the accelerator pedal opening of the engine, and a, b, c, d, and e be undetermined coefficients obtained by fitting engine bench test data.
[0052] S3.2: The exhaust waste heat energy simulation module is used to calculate parameters including engine exhaust waste heat energy and the proportion of waste heat energy. Among them, the engine exhaust waste heat energy is calculated based on exhaust flow rate, exhaust temperature, and specific heat capacity at constant pressure. The calculation formula is as follows:
[0053]
[0054] In the formula, To control the engine exhaust flow, and These are the specific heat capacities at constant pressure for the engine exhaust valve outlet and the ambient atmosphere, respectively. and These are the temperatures at the engine exhaust valve outlet and the ambient air, respectively.
[0055] S3.3: The flow rates of nitrogen oxides, hydrocarbons, and carbon monoxide are calculated using the emission pollutant simulation module. The calculation formula is as follows:
[0056] ( + )
[0057] ( + )
[0058] ( + )
[0059] In the formula, , , These are the flow rates of nitrogen oxides, hydrocarbons, and carbon monoxide, respectively, in g / h. , , These are the volume fractions of nitrogen oxides, hydrocarbons, and carbon monoxide, respectively, in ppm. This refers to fuel flow rate.
[0060] Combustion efficiency is calculated using pollutants that have not been completely burned. The formula is as follows:
[0061]
[0062] In the formula, , , , These represent fuel flow rate, hydrocarbon flow rate, carbon monoxide flow rate, and hydrogen flow rate, respectively. , , , These represent the lower heating values of fuel oil, hydrocarbons, carbon monoxide, and hydrogen, respectively. The energy released by the fuel and the energy lost due to unburning are calculated using the fuel flow rate, the lower heating value of the fuel oil, and the combustion efficiency.
[0063] S3.4: Calculate the engine heat transfer loss using the heat transfer process simulation module. The heat loss includes heat dissipation from the cooling system, lubricating oil, cylinder block, and system heat storage. The calculation formula for the cooling system's heat dissipation is as follows:
[0064]
[0065] In the formula, This refers to the flow rate of the engine coolant. and These are the inlet and outlet specific heat capacities at constant pressure of the engine coolant, respectively. and Do not specify the inlet and outlet temperatures of the engine coolant;
[0066] The formula for calculating the total heat transfer loss is as follows:
[0067]
[0068] In the formula, The total heat transfer loss is represented by m and n, which are undetermined coefficients obtained by fitting engine bench test data.
[0069] S3.5: Use the heat-work conversion process simulation module to obtain parameters including indicated power, indicated torque, indicated average pressure, indicated thermal efficiency, and indicated fuel consumption rate;
[0070] The heat calculation for converting the engine's thermal work process into the indicated power is as follows:
[0071]
[0072]
[0073] In the formula, The combustion efficiency of incompletely burned pollutants, This refers to the heat generated by fuel consumption.
[0074] S3.6: The mechanical loss simulation module is used to calculate parameters including mechanical loss power, average mechanical loss pressure, and mechanical efficiency. The mechanical loss simulation module includes friction loss and accessory power consumption. The work done by friction loss is calculated as follows:
[0075]
[0076] In the formula, The work lost due to engine friction is represented by A, B, C, D, and E, which are undetermined coefficients obtained by fitting engine bench test data.
[0077] S3.7: The effective performance parameter simulation module is used to calculate parameters including engine effective power and effective torque. The calculation formula is as follows:
[0078]
[0079]
[0080] In the formula, It is the engine's effective power. For the engine's effective torque, The external characteristic torque is the torque at the current engine speed, obtained by interpolating the external characteristic torque and the current engine speed. The engine torque percentage is read via the CAN bus.
[0081] S3.8: Model verification is achieved through hardware and software in the loop.
[0082] In summary, compared with the prior art, the beneficial effects of the above technical solution are:
[0083] (1) The engine twin model established using measured data and calculation formulas is relatively simple and can achieve real-time simulation; the engine verification model is realized using hardware and software in the loop, and the simulation accuracy is high. This engine digital twin model seeks a balance between simulation time and accuracy.
[0084] (2) Real-time data interaction between the physical engine and the engine twin model has been realized. The two coexist and influence each other. The initial data of the engine digital twin model is updated in real time, which is an online real-time simulation of the engine. At the same time, the simulation results will affect the actual working process of the engine. This is why it is called engine digital twin. Engine twin is not just a mathematical model, but the whole system including software, hardware and communication.
[0085] (3) Engine twin model can realize the performance simulation of the engine throughout the entire life cycle during the construction process of engineering machinery, and carry out engine parameter analysis, fault analysis and intelligent parameter control throughout the process, which is of great significance to the intelligent construction of engineering machinery;
[0086] (4) The present invention realizes online optimization of engine control strategy. The engine control strategy can be optimized by using engine twin model, thereby improving the overall operation performance of engineering machinery and realizing energy saving and emission reduction. The traditional engine ECU (electronic control unit) has limited computing power. The engine twin model runs on server (computer), so it can perform relatively complex calculations and analyses, which is equivalent to adding a super ECU to the engine. Attached Figure Description
[0087] Figure 1 This is an overall block diagram of an engine twin modeling system according to an embodiment of the present invention;
[0088] Figure 2 This is a structural block diagram of an engine twin model in an engine twin modeling system according to an embodiment of the present invention;
[0089] Figure 3 This is a flowchart illustrating an engine twin modeling method according to an embodiment of the present invention. Detailed Implementation
[0090] The principles and features of the present invention are described below with reference to all the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0091] This invention discloses an engine twin modeling system and modeling method.
[0092] In a first aspect, embodiments of the present invention provide an engine twin modeling system.
[0093] An engine twin modeling system includes a physical prototype, a server, and an engine twin model;
[0094] The physical prototype in this embodiment of the invention is an engineering machinery engine (rotary drilling rig and its mounted diesel engine);
[0095] The rotary drilling rig is equipped with a variety of sensors, controllers, data acquisition devices, data transmitters, and data receivers. Among them, the sensors include engine speed sensors, intake air pressure sensors, temperature sensors, exhaust temperature sensors, pressure sensors, exhaust oxygen sensors, and pollutant measurement sensors.
[0096] The controller includes a master controller and a slave controller. The master controller is responsible for processing signals from sensors, displays, and switch components. The slave controller is connected to the actuator via a CAN bus and receives signals from engine, hydraulic, and body position sensors via the CAN bus.
[0097] The data acquisition unit collects parameters from the physical prototype. Some parameters are collected directly from the CAN bus, while others are collected directly from sensors. Parameters collected from the CAN bus include engine speed, fuel injection quantity, torque percentage, intake pressure, and temperature; parameters collected from sensors include exhaust pressure, temperature, excess air coefficient, and contaminants.
[0098] The data transmitter sends data to the Internet via 5G signals, and the server directly reads the Ethernet data sent by the data transmitter.
[0099] The data receiver receives 5G signal data and transmits instructions to the actuator, thereby controlling the rotary drilling rig to carry out construction.
[0100] In this embodiment of the invention, the server is a computer used to interact with data on the physical prototype in real time. The computer has the operating environment of the engine twin model, including hardware and software conditions. The computer can communicate with the data sending device (data transmitter) and data receiving device (data receiver) on the physical prototype. Data or task instructions are transmitted through a 5G communication terminal to achieve real-time data interaction.
[0101] Because of the requirements of digital twins, computers possess strong data processing capabilities, large data storage capacity, and the ability to operate without failure for extended periods. Traditional engine ECUs have limited computing power, but engine twin models run on computers, allowing for more complex calculations and analyses—essentially adding a super ECU to the engine.
[0102] An engine twin model is a virtual twin of the actual engine, running in real time alongside the actual engine. The time taken for the engine twin model to calculate one working cycle is less than the actual working cycle time of the engine.
[0103] The engine twin model includes a parameter input module, a parameter output module, and a solution module, wherein:
[0104] The parameter input module has data analysis and data processing capabilities. It is used to input the initial data of the engine twin model. The initial data are parameters collected from the physical prototype, including engine speed, intake pressure, temperature, exhaust temperature, pressure, excess air coefficient, and pollutant measurement.
[0105] The parameter output module is used to output engine performance parameters obtained from the engine twin model simulation, enabling data display and storage. Engine power performance parameters include power and torque; economic performance parameters include effective fuel consumption and effective thermal efficiency; and emission performance parameters include carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter.
[0106] The solution module includes simulation modules for the ventilation process, exhaust waste heat energy, emission parameters, heat transfer process, heat-work conversion process, mechanical losses, and performance parameters.
[0107] The ventilation process simulation module is used to calculate the fresh intake air flow rate and EGR flow rate (exhaust gas recirculation flow rate) based on intake pressure, temperature, speed, and throttle opening, and to calculate the total fuel energy based on the fuel flow rate.
[0108] The exhaust waste heat energy simulation module is used to calculate the exhaust waste heat energy and the proportion of waste heat energy based on exhaust temperature and flow rate.
[0109] The emission parameter simulation module is used to calculate specific emissions and combustion efficiency based on intake air flow, fuel injection quantity, and pollutant volume emission.
[0110] The heat transfer process simulation module is used to calculate heat dissipation from the cooling system, lubricating oil, cylinder block, and system heat storage.
[0111] The heat-to-work conversion process simulation module is used to obtain engine indicated performance parameters, such as indicated power, indicated torque, indicated average pressure, indicated thermal efficiency, and indicated fuel consumption rate. It calculates the energy of piston work by subtracting combustion loss energy, exhaust waste heat energy, and heat transfer loss energy from total fuel energy, and then calculates the indicated performance. The energy corresponding to indicated work includes the energy of effective work and the energy of mechanical losses.
[0112] The mechanical loss simulation module is used to calculate the amount of mechanical loss based on engine speed and throttle opening.
[0113] The performance parameter simulation module is used to calculate engine power performance parameters based on engine speed and torque ratio, and to calculate economic performance parameters based on fuel quantity and engine operating conditions.
[0114] Secondly, the present invention provides a method for modeling an engine twin model.
[0115] An engine twin modeling method, applied to the aforementioned modeling system, includes the following steps:
[0116] S1: Real-time acquisition of key parameters of the physical prototype through multiple sensors and CAN bus.
[0117] Specifically, key engine parameters of the construction machinery are collected. Some parameters are read directly from the CAN bus, such as engine speed, fuel injection quantity, torque percentage, intake pressure, and temperature. Other parameters are collected directly from sensors, such as exhaust pressure, temperature, excess air coefficient, and pollutants.
[0118] Different parameters are used at different frequencies, but they are all based on time, meaning each parameter corresponds to a time period.
[0119] The data transmitter sends data to the Internet via 5G signals, and the computer directly reads the Ethernet data sent by the data transmitter.
[0120] S2: Transient data preprocessing of physical prototype.
[0121] S3: Run an engine twin model that can achieve digital twin.
[0122] Specifically, a twin model of the engine was established through modularization, and hardware-in-the-loop software was used to verify the model, improving the accuracy of online simulation of engine performance parameters. Once the simulation model (twin model) obtains the operating parameters of the physical prototype engine for one cycle, the simulation model automatically starts and calls the key engine parameters as the initial conditions for this simulation. Data input triggers the engine model to run.
[0123] S4: Adaptive control to complete the physical prototype simulation process.
[0124] Specifically, in S2, parameters are saved including the time, number, and parameter value. A time counter is added at the interface between the initial parameters and the model data to record the simulation time and runtime cycle number of the engine twin model. Obviously, the simulation time of the engine twin model is... The timing of the parameter acquisition lags behind the current acquisition time but should precede the next acquisition time; the model's running loop number matches the acquired parameter number. The runtime of the engine twin model in S3 should be shorter than the time difference between two parameter acquisitions. Therefore, after the model simulation is complete, there is still some time before the initial conditions (initial data) for the next loop can be read. After the engine twin model completes one calculation, the model's progress is preserved, and the model attempts to call new initial conditions until a new value is obtained. Whether the value is the latest initial condition can be determined by the time or loop number. The waiting time is shorter at high speeds (theoretically, no waiting is needed at maximum speed as the model operates continuously), and longer at low speeds, thus achieving adaptive control of the engine simulation process.
[0125] S5: Complete the physical prototype status assessment and control strategy feedback.
[0126] Specifically, in steps S1-S4 above, measured engine data and engine simulation data are obtained. These data are analyzed and processed to evaluate the engine's performance and provide feedback on control strategies and suggestions.
[0127] a. Real-time display of engine simulation results
[0128] Once the model calculations are complete, the engine's performance parameters can be obtained. The results are displayed in real time using specific numbers, curves, or bar charts, and saved as files. Key parameters such as effective power, torque, speed, effective thermal efficiency, effective fuel consumption, and specific emissions can be displayed on a dedicated monitor or transmitted to the dashboard of the construction machinery via 5G communication for reference by engineers or drivers.
[0129] b. Comparison of engine operating performance and engine bench performance
[0130] The engine's operating conditions are determined by engine speed and accelerator pedal position. The real-time calculated performance parameters are compared with those from engine bench tests to obtain and evaluate the engine's performance during construction. If the engine's performance during operation is found to be significantly worse than its performance on the engine bench, a warning signal is issued, requiring engine inspection and repair.
[0131] c. Comparison of engine steady-state and transient operating performance
[0132] The engine's performance under steady-state and transient conditions during actual operation is compared and evaluated. If transient conditions are frequent and performance deviates significantly, warnings and suggestions are provided regarding the driver's operating methods.
[0133] d. Performance comparison at different points in the engine's life cycle
[0134] Engine digital twins can obtain performance data throughout the entire engine's lifecycle, comparing current engine performance data with historical performance data under similar operating conditions. If significant performance deviations are found, recommendations can be made regarding engine fatigue, durability, and maintenance.
[0135] From then on, the physical prototype was put into operation on the construction site, transmitting the operating parameters to the engine model. The model calculated the simulation results, analyzed and processed the results, and fed them back to the physical prototype on the construction site. The two achieved data interaction and symbiosis, thus realizing the digital twin of the engine.
[0136] As another embodiment of the present invention, step S2 may include the following steps:
[0137] S2.1: Convert data based on engine time into data based on engine cycle.
[0138] Specifically, in order to facilitate data interaction and simulation calculations between the physical engine and the engine twin model, after the computer obtains the engine parameters, it uses the engine working cycle as a reference to preprocess the data, that is, one working cycle of the engine corresponds to a set of collected data.
[0139] Calculate the time t required for the engine to complete one cycle using the following formula:
[0140]
[0141] In the formula, n is the engine speed, and δ is related to the engine stroke. When the engine stroke is four-stroke, δ is 2, and when the engine stroke is two-stroke, δ is 1. If more than one data point is collected for a certain parameter within a time period, these data points are averaged to reduce the amount of data. If it takes several times longer to collect a data point for a certain parameter, the two collected data points are interpolated to ensure that each time point corresponds to one data point, thus filling in the data gaps. After the above processing, each engine working cycle corresponds to one value, one time, and one number for each parameter.
[0142] S2.2: Complete the display of key engine parameters and the preprocessing of initial engine model data.
[0143] Specifically, the directly collected engine parameters, such as engine speed, accelerator pedal opening, and fuel flow, are displayed in the form of specific numbers, curves, or bar charts.
[0144] The initial conditions (initial data) required for the engine twin model, such as intake and exhaust temperature and pressure, temperature, throttle pedal opening, and engine speed, are stored as files in a folder on the computer for the model to access. To facilitate subsequent model access and personnel review, each parameter should be saved with the time, number, and parameter value.
[0145] As another embodiment of the present invention, step S3 may include the following steps:
[0146] S3.1: The intake volume parameters, including intake flow rate, filling coefficient, and EGR flow rate, are calculated using the ventilation process simulation module.
[0147] Specifically, based on engine structural parameters (bore, stroke, compression ratio, etc.), as well as engine accelerator pedal position, compressor post-pressurization pressure and temperature, parameters of the engine's scavenging process, such as the volumetric efficiency, are calculated. The actual intake airflow of the engine is calculated as follows:
[0148]
[0149] In the formula, It's the air intake flow rate. It is the pressure after the compressor. It is the engine charge coefficient. It refers to engine displacement. It refers to the number of engine cylinders. It is the gas constant of air. This refers to the intake manifold temperature. The diesel engine's volumetric efficiency is closely related to engine speed and accelerator pedal position, especially engine speed. The volumetric efficiency is calculated as follows:
[0150]
[0151] In the formula, Let be the accelerator pedal opening of the engine, and a, b, c, d, and e be undetermined coefficients obtained by fitting engine bench test data.
[0152] Excess air coefficient measured by oxygen sensor and fuel flow The intake airflow can also be calculated, and the two methods for obtaining intake airflow can be mutually verified. The calculation formula is:
[0153]
[0154] In the formula, The theoretical air-fuel ratios are approximately 14.3 for diesel and 14.7 for gasoline. This is the excess air coefficient.
[0155] Furthermore, the EGR flow rate can also be calculated based on the intake air flow rate and EGR rate. The formula is as follows:
[0156]
[0157] In the formula, EGR rate For EGR traffic.
[0158] S3.2: The exhaust waste heat energy simulation module is used to calculate parameters including engine exhaust waste heat energy and the proportion of waste heat energy. Among them, the engine exhaust waste heat energy is calculated based on exhaust flow rate, exhaust temperature, and specific heat capacity at constant pressure. The calculation formula is as follows:
[0159]
[0160] In the formula, To control the engine exhaust flow, and These are the specific heat capacities at constant pressure for the engine exhaust valve outlet and the ambient atmosphere, respectively. and These are the temperatures at the engine exhaust valve outlet and the ambient air, respectively.
[0161] S3.3: The flow rates of nitrogen oxides, hydrocarbons, and carbon monoxide are calculated using the emission pollutant simulation module.
[0162] Specifically, engine emissions mainly include hydrocarbons, nitrogen oxides, carbon monoxide, sulfur dioxide, carbon dioxide, and particulate matter. During testing, emissions are typically expressed as a volume percentage. The total exhaust flow rate can be calculated by adding the intake airflow to the fuel flow rate during the scavenging process; the formula is as follows:
[0163] ( + )
[0164] ( + )
[0165] ( + )
[0166] In the formula, , , These are the flow rates of nitrogen oxides, hydrocarbons, and carbon monoxide, respectively, in g / h. , , These are the volume fractions of nitrogen oxides, hydrocarbons, and carbon monoxide, respectively, in ppm. Fuel flow rate;
[0167] Combustion efficiency is calculated using pollutants that have not been completely burned. The formula is as follows:
[0168]
[0169] In the formula, , , , These represent fuel flow rate, hydrocarbon flow rate, carbon monoxide flow rate, and hydrogen flow rate, respectively. , , , These represent the lower heating values of fuel oil, hydrocarbons, carbon monoxide, and hydrogen, respectively. The energy released by the fuel and the energy lost due to unburning are calculated using the fuel flow rate, the lower heating value of the fuel oil, and the combustion efficiency.
[0170] S3.4: Calculate engine heat transfer loss using the heat transfer process simulation module.
[0171] Specifically, the heat loss in an engine includes heat dissipation from the cooling system, lubricating oil, cylinder block, and system heat storage. Among these, the cooling system dissipates the most heat. Furthermore, the amount of heat dissipation is closely related to the in-cylinder combustion temperature. The cooling system's heat dissipation power is calculated using the exhaust valve outlet temperature, using the following formula:
[0172]
[0173] In the formula, The flow rate of the engine coolant. and These are the inlet and outlet specific heat capacities at constant pressure of the engine coolant, respectively. and Do not specify the inlet and outlet temperatures of the engine coolant;
[0174] The formula for calculating the total heat transfer loss is as follows:
[0175]
[0176] In the formula, The total heat transfer loss is denoted as , and m and n are undetermined coefficients, which are obtained by fitting engine bench test data.
[0177] S3.5: Use the heat-work conversion process simulation module to obtain parameters including indicated power, indicated torque, indicated average pressure, indicated thermal efficiency, and indicated fuel consumption rate.
[0178] Specifically, the simulation of the heat-to-work conversion process is to obtain engine indicated performance parameters, such as indicated power, indicated torque, indicated average pressure, indicated thermal efficiency, and indicated fuel consumption rate.
[0179] The heat calculation for converting the engine's thermal work process into the indicated power is as follows:
[0180]
[0181]
[0182] In the formula, The combustion efficiency of incompletely burned pollutants, This represents the heat generated by the fuel consumption power.
[0183] S3.6: Parameters including mechanical loss power, average mechanical loss pressure, and mechanical efficiency are calculated using the mechanical loss simulation module.
[0184] Specifically, the mechanical loss simulation module includes friction loss and accessory power consumption. The work done by friction loss is calculated as follows:
[0185]
[0186] In the formula, Let A, B, C, D, and E represent the work lost due to engine friction. These coefficients are undetermined and obtained by fitting engine bench test data.
[0187] The power consumption of accessories refers to the power consumption of accessories that maintain the normal operation of the engine. These mainly include the power consumption of water pumps, oil pumps, fans, and electrical components. The power consumption of water pumps and oil pumps is calculated based on the pressure and flow rate of coolant and lubricating oil, while the power consumption of the fan motor is calculated based on current and voltage.
[0188] S3.7: Parameters including engine effective power and effective torque are calculated using the effective performance parameter simulation module.
[0189] Specifically, the formulas for calculating the engine's effective power and effective torque are as follows:
[0190]
[0191]
[0192] In the formula, It is the engine's effective power. The effective torque of the engine. The external characteristic torque is the torque at the current engine speed, obtained by interpolating the external characteristic torque and the current engine speed. The engine torque percentage is obtained via the CAN bus.
[0193] The effective torque of the engine is calculated based on the ratio of the engine's external characteristic torque to the measured torque. Combined with the engine speed, the effective power of the engine can be calculated. The engine's power performance is evaluated by considering factors such as engine speed, effective torque, and effective power. The effective fuel consumption rate of the engine is calculated based on the fuel flow rate and the engine's effective power. Combined with the fuel's calorific value, the effective thermal efficiency is calculated. The engine's economic performance is evaluated by considering factors such as fuel flow rate, effective fuel consumption rate, and effective thermal efficiency.
[0194] S3.8: Model verification is achieved through hardware and software in the loop.
[0195] Specifically, as mentioned earlier, there is some redundancy between the engine simulation module and the measured data, or there is an inherent connection between the simulation modules. Utilizing this hardware-in-the-loop relationship allows for model verification, improving the accuracy of online simulation of engine performance parameters.
[0196] For example, the scavenging process simulation module can calculate the airflow rate by measuring the excess air coefficient and fuel flow rate, thus verifying the scavenging process simulation module. The mechanical loss power calculated in S3.6 plus the effective power calculated in S3.7 equals the indicated power calculated in S3.5. This relationship allows for the constraint and verification of these three modules, and any deviations can be corrected for the relevant modules. The accuracy of the simulation results for other simulation modules can be ensured by verifying the sensor measurement accuracy.
[0197] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A twin modeling system for an engine, characterized in that, This includes physical prototypes, server and engine twin models; The physical prototype is a rotary drilling rig and its diesel engine; The rotary drilling rig is equipped with various sensors, controllers, data acquisition devices, data transmitters, and data receivers, among which: The data acquisition device collects parameters from the physical prototype. Some parameters are collected directly from the CAN bus, while others are collected directly from the sensors. The server is used to interact with data on the physical prototype in real time, and the server has a running environment for the engine twin model; The engine twin model is a virtual twin of the actual engine, running in real time along with the actual engine. The time for the engine twin model to calculate one working cycle is less than the actual working cycle time of the engine. The engine twin model includes a parameter input module, a parameter output module, and a solution module, wherein: The parameter input module has data analysis and data processing capabilities. The parameter input module is used to input the initial data of the engine twin model. The initial data are parameters collected from the physical prototype, including engine speed, intake pressure, temperature, exhaust temperature, pressure, excess air coefficient, and pollutant measurement. The parameter output module is used to output the engine performance parameters obtained from the engine twin model simulation, and to display and store the data; The solution module includes a ventilation process simulation module, an exhaust waste heat energy simulation module, an emission parameter simulation module, a heat transfer process simulation module, a heat-work conversion process simulation module, a mechanical loss simulation module, and a performance parameter simulation module, wherein: The ventilation process simulation module is used to calculate the fresh intake air flow and EGR flow based on the intake pressure, temperature, speed, and throttle opening, and to calculate the total fuel energy based on the fuel flow. The exhaust waste heat energy simulation module is used to calculate the exhaust waste heat energy and the proportion of waste heat energy based on exhaust temperature and flow rate. The emission parameter simulation module is used to calculate the specific emission and combustion efficiency based on the intake air volume, fuel injection volume, and pollutant volume emission volume. The heat transfer process simulation module is used to calculate heat dissipation from the cooling system, lubricating oil, cylinder, and system heat storage. The heat-work conversion process simulation module is used to obtain engine indicated performance parameters; The mechanical loss simulation module is used to calculate the amount of mechanical loss based on engine speed and throttle opening. The performance parameter simulation module is used to calculate engine power performance parameters based on engine speed and torque ratio, and to calculate economic performance parameters based on fuel quantity and engine operating conditions.
2. The engine twin modeling system according to claim 1, characterized in that: Parameters collected from the CAN bus include engine speed, fuel injection quantity, torque percentage, intake pressure, and temperature; parameters collected from sensors include exhaust pressure, temperature, excess air coefficient, and contaminants.
3. The engine twin modeling system according to claim 1, characterized in that: The sensors include an engine speed sensor, an intake air pressure sensor, a temperature sensor, an exhaust temperature sensor, a pressure sensor, an exhaust oxygen sensor, and a pollutant measurement sensor.
4. The engine twin modeling system according to claim 1, characterized in that: The controller includes a master controller and a slave controller. The master controller is responsible for processing signals from sensors, displays, and switch components. The slave controller is connected to the actuator via a CAN bus and receives signals from engine, hydraulic, and fuselage position sensors via the CAN bus.
5. The engine twin modeling system according to claim 4, characterized in that: The data transmitter sends data to the Internet via 5G signals, and the server directly reads the Ethernet data sent by the data transmitter.
6. The engine twin modeling system according to claim 5, characterized in that: The data receiver receives 5G signal data and transmits the signal to the actuator to control the construction of the physical prototype.
7. A method for modeling an engine twin model, characterized in that: The modeling system applied to any one of claims 1-6 includes the following steps: S1: Real-time acquisition of key parameters of the physical prototype through multiple sensors and CAN bus; S2: Transient data preprocessing of physical prototype; S3: Run an engine twin model that can achieve digital twin; S4: Adaptive control to complete the physical prototype simulation process; S5: Complete the physical prototype status assessment and control strategy feedback.
8. The engine twin modeling method according to claim 7, characterized in that: Step S2 specifically includes: S2.1: Convert the data based on engine time to data based on engine cycle, where one engine working cycle corresponds to one set of collected data. Calculate the time t required for one engine working cycle using the following formula: In the formula, n is the engine speed, and δ is related to the engine stroke. When the engine stroke is four-stroke, δ is 2, and when the engine stroke is two-stroke, δ is 1. If more than one data point is collected for a certain parameter within a time period, these data points are averaged to reduce the amount of data. If it takes several times longer to collect a data point for a certain parameter, the two collected data points are interpolated to ensure that each time point corresponds to one data point, thus filling in the data gaps. After the above processing, each engine working cycle corresponds to one value, one time, and one number for each parameter. S2.2: Complete the display of key engine parameters and the preprocessing of initial engine model data.
9. The engine twin modeling method according to claim 8, characterized in that: Step S3 specifically includes: S3.1: The parameters including intake airflow, volumetric efficiency, and EGR flow are calculated using the scavenging process simulation module. The actual intake airflow of the engine is calculated as follows: In the formula, It's the air intake flow rate. It is the pressure after the compressor. It is the engine charge coefficient. It refers to engine displacement. It refers to the number of engine cylinders. It is the gas constant of air. This refers to the intake manifold temperature, where the volumetric efficiency is calculated as follows: In the formula, Let be the accelerator pedal opening of the engine, and a, b, c, d, and e be undetermined coefficients obtained by fitting engine bench test data. S3.2: The exhaust waste heat energy simulation module is used to calculate parameters including engine exhaust waste heat energy and the proportion of waste heat energy. Among them, the engine exhaust waste heat energy is calculated based on exhaust flow rate, exhaust temperature, and specific heat capacity at constant pressure. The calculation formula is as follows: In the formula, To control the engine exhaust flow, and These are the specific heat capacities at constant pressure for the engine exhaust valve outlet and the ambient atmosphere, respectively. and These are the temperatures at the engine exhaust valve outlet and the ambient air, respectively. S3.3: The flow rates of nitrogen oxides, hydrocarbons, and carbon monoxide are calculated using the emission pollutant simulation module. The calculation formula is as follows: ( + ) ( + ) ( + ) In the formula, , , These are the flow rates of nitrogen oxides, hydrocarbons, and carbon monoxide, respectively, in g / h. , , These are the volume fractions of nitrogen oxides, hydrocarbons, and carbon monoxide, respectively, in ppm. Fuel flow rate; Combustion efficiency is calculated using pollutants that have not been completely burned. The formula is as follows: In the formula, , , , These represent fuel flow rate, hydrocarbon flow rate, carbon monoxide flow rate, and hydrogen flow rate, respectively. , , , These represent the lower heating values of fuel oil, hydrocarbons, carbon monoxide, and hydrogen, respectively. The energy released by the fuel and the energy lost due to unburning are calculated using the fuel flow rate, the lower heating value of the fuel oil, and the combustion efficiency. S3.4: Calculate engine heat transfer loss using the heat transfer process simulation module. The heat loss includes heat dissipation from the cooling system, lubricating oil, cylinder block, and system heat storage. The calculation formula for cooling system heat dissipation is as follows: In the formula, The flow rate of the engine coolant. and These are the inlet and outlet specific heat capacities at constant pressure of the engine coolant, respectively. and Do not specify the inlet and outlet temperatures of the engine coolant; The formula for calculating the total heat transfer loss is as follows: In the formula, The total heat transfer loss is represented by m and n, which are undetermined coefficients obtained by fitting engine bench test data. S3.5: Parameters including indicated power, indicated torque, indicated average pressure, indicated thermal efficiency, and indicated fuel consumption rate are obtained using the heat-to-work conversion process simulation module. The heat calculation for converting the engine's thermal work process into the indicated power is as follows: In the formula, The combustion efficiency of incompletely burned pollutants, This refers to the heat generated by fuel consumption. S3.6: The mechanical loss simulation module is used to calculate parameters including mechanical loss power, average mechanical loss pressure, and mechanical efficiency. The mechanical loss simulation module includes friction loss and accessory power consumption. The work done by friction loss is calculated as follows: In the formula, The work lost due to engine friction is represented by A, B, C, D, and E, which are undetermined coefficients obtained by fitting engine bench test data. S3.7: The effective performance parameter simulation module is used to calculate parameters including engine effective power and effective torque. The calculation formula is as follows: In the formula, It is the engine's effective power. The effective torque of the engine. The external characteristic torque is the torque at the current engine speed, obtained by interpolating the external characteristic torque and the current engine speed. The engine torque percentage is read via the CAN bus. S3.8: Model verification is achieved through hardware and software in the loop.