Natural gas-diesel oil injection switching control system of dual-fuel diesel engine

Abstract

The invention discloses a natural gas-diesel oil injection switching control system of a dual-fuel diesel engine, which relates to the technical field of automatic control and comprises a data acquisition monitoring module, a fuel analysis module, a prediction control module, a control optimization module and a switching protection module. Engine operation parameter data are collected in real time through an engine sensor interface and preprocessed, and fuel dynamic proportion analysis is carried out according to different rotating speeds and load intervals of an engine by taking a preset proportion as an initial reference datum and applying an intelligent algorithm; the engine can obtain the most appropriate natural gas and diesel oil mixing proportion under various working conditions, according to an ideal gas state equation, based on pressure and temperature data, monitored in real time, in a gas supply pipeline, dynamic compensation is conducted on the gas volume flow, real-time gas supply energy is calculated, the gas supply amount can be accurately controlled in the mode, and the gas supply efficiency is improved. It is guaranteed that the engine obtains stable and accurate energy supply, and therefore stable operation of the engine is maintained.

Description

Technical Field

[0001] This invention relates to the field of automation control technology, and in particular to a natural gas-diesel injection switching control system for a dual-fuel diesel engine. Background Technology

[0002] Traditional diesel engines rely primarily on diesel fuel. This energy structure makes them vulnerable to diesel shortages and price fluctuations. Furthermore, diesel combustion emits significant amounts of pollutants, such as nitrogen oxides (NOx) and particulate matter (PM), severely impacting the environment. To address these issues, dual-fuel diesel engines have emerged. By introducing natural gas as a partial alternative fuel, dependence on diesel is alleviated to some extent, and the relatively cleaner combustion characteristics of natural gas help reduce pollutant emissions. However, in the practical application of dual-fuel diesel engines, the natural gas-diesel injection switching control has become a key challenge restricting their full performance.

[0003] In existing technologies, the acquisition of operating parameters for dual-fuel diesel engines is often not accurate enough, and the acquired data lacks an effective preprocessing mechanism. This results in subsequent modules being unable to obtain an accurate and reliable data foundation, making it difficult to accurately assess the engine's operating status. Consequently, it affects the accurate decision-making and effective control of the entire control system. In terms of fuel ratio control, traditional systems mostly adopt a fixed fuel mixing ratio, which cannot be flexibly adjusted according to different engine speeds and load ranges. This makes it difficult for the engine to obtain the most suitable natural gas and diesel mixing ratio under various operating conditions, resulting in low fuel utilization efficiency. Typically, the real-time changes in pressure and temperature in the gas supply pipeline are not considered, and dynamic compensation for gas volume flow rate cannot be made based on these factors. This makes it difficult for the engine to obtain a stable and accurate energy supply, seriously affecting the overall performance and operational stability of the engine.

[0004] To address the aforementioned technical shortcomings, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to improve the overall performance and operational stability of an engine by performing rolling time-domain optimization with emissions and torque stability as multiple objectives, generating the optimal fuel substitution rate time-series trajectory, effectively balancing the relationship between engine emissions and torque stability, and ensuring the stability of engine output torque while reducing pollutant emissions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a natural gas-diesel injection switching control system for a dual-fuel diesel engine, comprising a data acquisition and monitoring module, a fuel analysis module, a predictive control module, a control optimization module, and a switching protection module;

[0007] The data acquisition and monitoring module collects engine operating parameter data in real time through the engine sensor interface and preprocesses the collected raw operating parameter data.

[0008] The fuel analysis module, based on preprocessed engine operating parameter data, uses a preset natural gas to diesel standard ratio as the initial reference benchmark, and employs intelligent algorithms to perform dynamic fuel ratio analysis of natural gas and diesel. According to different engine speeds and load ranges, it calculates and outputs the target mixing ratio control parameters of natural gas and diesel.

[0009] The control optimization module, based on real-time monitoring of pressure and temperature data in the gas supply pipeline, dynamically compensates the gas volume flow rate according to the ideal gas state equation, and calculates the real-time gas supply energy based on unit time.

[0010] The predictive control module inputs the preprocessed engine operating parameter data and real-time fuel supply energy into the engine dynamic prediction model, performs rolling time-domain optimization with emissions and torque stability as multiple objectives, and generates the optimal fuel substitution rate time-series trajectory.

[0011] The switching control module, based on the optimal fuel substitution rate timing trajectory, converts it into operation commands for the equipment, driving the dual-fuel injector to perform gradual coordinated actions of switching between diesel mode, dual-fuel mode, and the two.

[0012] Furthermore, engine operating parameter data is collected in real time through the engine sensor interface, specifically including the following:

[0013] S100. The operating parameter data includes engine speed, load, gas pressure, gas temperature, exhaust temperature, and oxygen sensor signal. The collected raw operating parameter data is preprocessed, including data filtering to remove noise interference and data normalization to make the data fall within a uniform dimension range.

[0014] S101. Perform range and gradient checks on the original operating parameters, including determining whether the data is within the preset reasonable upper and lower limits and whether the rate of change of the data is within the physically possible range.

[0015] S102. The checked valid data is combined in a timing sequence according to the control algorithm to generate preprocessed operating parameter data.

[0016] Furthermore, based on the preprocessed engine operating parameter data, and using a preset natural gas to diesel standard ratio as the initial reference benchmark, the specific process is as follows:

[0017] S200. Based on the preprocessed operating parameter data, extract key parameters closely related to fuel combustion and engine performance, conduct engine operating status analysis, and obtain engine operating status evaluation indicators.

[0018] S201. Based on the ideal values ​​of the various state evaluation indicators obtained, and in conjunction with the engine operating state evaluation indicators obtained in real time, a comparative analysis is conducted to obtain the deviation values ​​between the actual indicators and the ideal indicators.

[0019] S202. Based on the engine's performance requirements and operational safety considerations, set reasonable deviation thresholds for each status assessment indicator.

[0020] Furthermore, based on different engine speeds and load ranges, the target mixing ratio control parameters for natural gas and diesel are calculated and output. The specific steps are as follows:

[0021] S300. Based on the obtained engine speed and load ranges, and combined with the mixing ratio control parameters corresponding to the different speed and load ranges, the speed and load ranges are divided into several smaller ranges, forming multiple speed and load ranges and mixing ratio control parameter mapping tables. With speed and load as input variables, mixing ratio as output variable, and engine performance parameters as constraints, a mathematical model is established using multiple regression analysis to predict the mixing ratio under different operating conditions.

[0022] S301. Calculate the initial mixing ratio of natural gas and diesel for each range based on the mapping table of speed and load ranges and mixing ratio control parameters.

[0023] Furthermore, the gas volume flow rate is dynamically compensated according to the ideal gas law, and the specific process is as follows:

[0024] S400: Obtain the pressure and temperature data in the gas supply pipeline under real-time monitoring, define the standard state and determine the benchmark, and obtain the density value of the gas under the standard state from the gas composition analysis table.

[0025] S401. Compensate the measured volumetric flow rate with pressure and temperature, and calculate the actual mass flow rate of the gas under the actual conditions using the actual density of the gas.

[0026] S402. Combine the mass flow rate with the energy characteristics of the gas to obtain the current calorific value of the gas and calculate the final real-time gas supply energy.

[0027] Furthermore, the optimal fuel substitution rate time-series trajectory is generated, and the specific process is as follows:

[0028] S500: The dynamic prediction model is constructed based on neural networks. The model is initialized according to the actual characteristics of the engine and historical operating data, including the initial values ​​of model parameters, network structure and activation function.

[0029] Based on relevant emission standards and engine emission characteristics, an emission objective function is constructed. Typically, a weighted summation method can be used to combine the emission indicators of multiple pollutants into a comprehensive emission indicator. The fluctuation of engine torque is calculated, and the standard deviation or variance of torque can be used to measure the stability of torque. The emission objective function and the torque stability objective function are combined into a multi-objective comprehensive optimization function.

[0030] S501. Taking the multi-objective comprehensive optimization function as the objective, within the feasible range of fuel substitution rate, find the optimal fuel substitution rate sequence that minimizes the value of the multi-objective comprehensive optimization function, and form the optimal fuel substitution rate time series trajectory.

[0031] Furthermore, the dual-fuel injector is driven to perform a gradual, coordinated action switching between diesel mode, dual-fuel mode, and the two modes. The specific process is as follows:

[0032] S600: Read the generated optimal fuel substitution rate time-series trajectory data, analyze the fuel substitution rate time-series trajectory, and determine the key time nodes for mode switching;

[0033] S601. Based on the engine performance and the control requirements of the dual-fuel injector, set a reasonable fuel substitution rate threshold. When the fuel substitution rate is less than the set diesel mode threshold, generate a diesel mode operation command. When the fuel substitution rate is greater than the set dual-fuel mode threshold, generate a dual-fuel mode operation command.

[0034] S602. Generate corresponding diesel mode, dual-fuel mode or transition mode operation commands, arrange the operation commands in chronological order to form an operation command sequence, send the operation commands and drive the dual-fuel injector to execute.

[0035] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0036] The natural gas-diesel injection switching control system of this dual-fuel diesel engine collects and preprocesses engine operating parameter data in real time through the engine sensor interface. Using a preset ratio as the initial reference, it employs intelligent algorithms to perform dynamic fuel ratio analysis based on different engine speeds and load ranges. This ensures that the engine obtains the most suitable natural gas to diesel mixture ratio under various operating conditions, which helps improve fuel utilization efficiency. Based on the ideal gas law, it dynamically compensates for the gas volume flow rate based on real-time monitoring of pressure and temperature data in the gas supply pipeline, and calculates the real-time gas supply energy. This method can accurately control the gas supply, ensuring that the engine receives a stable and precise energy supply, thereby maintaining stable engine operation and improving the overall performance and operational stability of the engine. With emissions and torque stability as multiple objectives, it performs rolling time-domain optimization to generate the optimal fuel substitution rate time-series trajectory, effectively balancing the relationship between engine emissions and torque stability. While reducing pollutant emissions, it ensures the stability of engine output torque. Attached Figure Description

[0037] Figure 1 A schematic diagram of the overall system flow structure of the present invention is shown. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1:

[0040] like Figure 1 As shown, the natural gas-diesel injection switching control system for a dual-fuel diesel engine includes a data acquisition and monitoring module, a fuel analysis module, a predictive control module, a control optimization module, and a switching protection module.

[0041] The data acquisition and monitoring module collects engine operating parameter data in real time through the engine sensor interface and preprocesses the collected raw operating parameter data.

[0042] The fuel analysis module, based on preprocessed engine operating parameter data, uses a preset natural gas to diesel standard ratio as the initial reference benchmark, and employs intelligent algorithms to perform dynamic fuel ratio analysis of natural gas and diesel. According to different engine speeds and load ranges, it calculates and outputs the target mixing ratio control parameters of natural gas and diesel.

[0043] The control optimization module, based on real-time monitoring of pressure and temperature data in the gas supply pipeline, dynamically compensates the gas volume flow rate according to the ideal gas state equation, and calculates the real-time gas supply energy based on unit time.

[0044] The predictive control module inputs the preprocessed engine operating parameter data and real-time fuel supply energy into the engine dynamic prediction model, performs rolling time-domain optimization with emissions and torque stability as multiple objectives, and generates the optimal fuel substitution rate time-series trajectory.

[0045] The switching control module, based on the optimal fuel substitution rate timing trajectory, converts it into operation commands for the equipment, driving the dual-fuel injector to perform gradual coordinated actions of switching between diesel mode, dual-fuel mode, and the two.

[0046] Real-time acquisition of engine operating parameter data via engine sensor interface, specifically including the following:

[0047] S100. The operating parameter data includes engine speed, load, gas pressure, gas temperature, exhaust temperature, and oxygen sensor signal. The collected raw operating parameter data is preprocessed, including data filtering to remove noise interference and data normalization to make the data fall within a uniform dimension range.

[0048] S101. Perform range and gradient checks on the original operating parameters, including determining whether the data is within the preset reasonable upper and lower limits and whether the rate of change of the data is within the physically possible range.

[0049] S102. The checked valid data is combined in a timing sequence according to the control algorithm to generate preprocessed operating parameter data.

[0050] Based on the preprocessed engine operating parameter data, and using the preset natural gas to diesel standard ratio as the initial reference benchmark, the specific process is as follows:

[0051] S200. Based on the preprocessed operating parameter data, extract key parameters closely related to fuel combustion and engine performance, conduct engine operating status analysis, and obtain engine operating status evaluation indicators.

[0052] S201. Based on the ideal values ​​of the various state evaluation indicators obtained, and in conjunction with the engine operating state evaluation indicators obtained in real time, a comparative analysis is conducted to obtain the deviation values ​​between the actual indicators and the ideal indicators.

[0053] S202. Based on the engine's performance requirements and operational safety considerations, set reasonable deviation thresholds for each status assessment indicator.

[0054] Based on different engine speeds and load ranges, the target mixing ratio control parameters for natural gas and diesel are calculated and output. The specific steps are as follows:

[0055] S300. Based on the obtained engine speed and load ranges, and combined with the mixing ratio control parameters corresponding to the different speed and load ranges, the speed and load ranges are divided into several smaller ranges, forming multiple speed and load ranges and mixing ratio control parameter mapping tables. With speed and load as input variables, mixing ratio as output variable, and engine performance parameters as constraints, a mathematical model is established using multiple regression analysis to predict the mixing ratio under different operating conditions.

[0056] S301. Calculate the initial mixing ratio of natural gas and diesel for each range based on the mapping table of speed and load ranges and mixing ratio control parameters.

[0057] The dynamic compensation of the gas volume flow rate is performed based on the ideal gas law, and the specific process is as follows:

[0058] S400: Obtain the pressure and temperature data in the gas supply pipeline under real-time monitoring, define the standard state and determine the benchmark, and obtain the density value of the gas under the standard state from the gas composition analysis table.

[0059] S401. Compensate the measured volumetric flow rate with pressure and temperature, and calculate the actual mass flow rate of the gas under the actual conditions using the actual density of the gas.

[0060] S402. Combine the mass flow rate with the energy characteristics of the gas to obtain the current calorific value of the gas and calculate the final real-time gas supply energy.

[0061] The optimal fuel substitution rate time-series trajectory is generated as follows:

[0062] S500: The dynamic prediction model is constructed based on neural networks. The model is initialized according to the actual characteristics of the engine and historical operating data, including the initial values ​​of model parameters, network structure and activation function.

[0063] Based on relevant emission standards and engine emission characteristics, an emission objective function is constructed. Typically, a weighted summation method can be used to combine the emission indicators of multiple pollutants into a comprehensive emission indicator. The fluctuation of engine torque is calculated, and the standard deviation or variance of torque can be used to measure the stability of torque. The emission objective function and the torque stability objective function are combined into a multi-objective comprehensive optimization function.

[0064] S501. Taking the multi-objective comprehensive optimization function as the objective, within the feasible range of fuel substitution rate, find the optimal fuel substitution rate sequence that minimizes the value of the multi-objective comprehensive optimization function, and form the optimal fuel substitution rate time series trajectory.

[0065] The dual-fuel injector is driven to perform a gradual, coordinated action that switches between diesel mode, dual-fuel mode, and between the two. The specific process is as follows:

[0066] S600: Read the generated optimal fuel substitution rate time-series trajectory data, analyze the fuel substitution rate time-series trajectory, and determine the key time nodes for mode switching;

[0067] S601. Based on the engine performance and the control requirements of the dual-fuel injector, set a reasonable fuel substitution rate threshold. When the fuel substitution rate is less than the set diesel mode threshold, generate a diesel mode operation command. When the fuel substitution rate is greater than the set dual-fuel mode threshold, generate a dual-fuel mode operation command.

[0068] S602. Generate corresponding diesel mode, dual-fuel mode or transition mode operation commands, arrange the operation commands in chronological order to form an operation command sequence, send the operation commands and drive the dual-fuel injector to execute.

[0069] The size of the interval and threshold is set to facilitate comparison. The size of the threshold depends on the amount of sample data and the number of bases set by those skilled in the art for each set of sample data; as long as it does not affect the ratio between the parameter and the quantized value.

[0070] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0071] In the two embodiments provided in this application, it should be understood that the disclosed apparatus and system can be implemented in other ways; for example, the apparatus embodiments described above are merely illustrative, and the division of modules is merely a logical functional division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed; furthermore, the coupling or direct coupling or communication connection between the shown or discussed mutuals can be through some interfaces, and the indirect coupling or communication connection between the apparatus or modules can be electrical, mechanical or other forms.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A natural gas-diesel injection switching control system for a dual-fuel diesel engine, characterized by, The system comprises a data acquisition and monitoring module, a fuel analysis module, a predictive control module, a control optimization module, and a switching protection module. The data acquisition and monitoring module acquires engine operating parameter data in real time through an engine sensor interface and pre-processes the acquired raw operating parameter data. The fuel analysis module, based on the pre-processed engine operating parameter data, uses an intelligent algorithm to analyze the dynamic proportion of natural gas and diesel fuel, taking the preset standard proportion of natural gas and diesel as the initial reference benchmark, and calculates and outputs the target mixing proportion control parameters of natural gas and diesel according to different engine speed and load intervals. The control optimization module, based on the real-time monitored pressure and temperature data in the gas supply pipeline, dynamically compensates the gas volume flow according to the ideal gas state equation, and calculates the real-time gas supply energy per unit time. The predictive control module inputs the pre-processed engine operating parameter data and real-time gas supply energy into an engine dynamic prediction model to perform multi-objective rolling horizon optimization in terms of emission and torque smoothness, and generates an optimal fuel replacement rate time sequence trajectory. The switching control module, based on the optimal fuel replacement rate time sequence trajectory, converts it into operation instructions for the equipment, and drives the dual-fuel injector to perform gradual and collaborative actions in diesel mode, dual-fuel mode, and switching between the two modes.

2. The natural gas-diesel injection switching control system of a dual-fuel diesel engine according to claim 1, characterized by, The engine operating parameter data is acquired in real time through an engine sensor interface, including the following steps: S100, the operating parameter data includes engine speed, load, gas pressure, gas temperature, exhaust temperature, and oxygen sensor signal. The acquired raw operating parameter data is pre-processed, including data filtering to remove noise interference and data normalization to ensure the data is within a unified dimension range. S101, the raw operating parameter data is checked for range and gradient, including whether the data is within the preset reasonable upper and lower limits and whether the data change rate is within the physically possible range. S102, the valid data after checking is combined in time sequence according to the control algorithm to generate pre-processed operating parameter data.

3. The natural gas-diesel injection switching control system of a dual-fuel diesel engine according to claim 1, characterized by, Based on the pre-processed engine operating parameter data, the preset standard proportion of natural gas and diesel is taken as the initial reference benchmark, and the specific process is as follows: S200, based on the pre-processed operating parameter data, the key parameters closely related to fuel combustion and engine performance are extracted for engine operating state analysis, and engine operating state evaluation indexes are obtained. S201, the ideal values of the obtained state evaluation indexes are compared with the real-time calculated engine operating state evaluation indexes to obtain the deviation values between the actual and ideal indexes. S202, reasonable deviation thresholds are set for each state evaluation index based on the performance requirements and operating safety considerations of the engine.

4. The natural gas-diesel injection switching control system of a dual-fuel diesel engine according to claim 1, characterized by, According to different engine speed and load intervals, the target mixing proportion control parameters of natural gas and diesel are calculated and output, with the following specific steps: S300, according to the obtained engine different speed and load interval, and combined with different speed and load interval corresponding mixed ratio control parameter, the speed and load interval division is carried out, the speed and load range is divided into several small intervals respectively, a plurality of speed and load interval and mixed ratio control parameter mapping table is formed, taking the speed and load as input variables, the mixed ratio as output variable, and the engine performance parameter as constraint condition, a mathematical model is established by using multiple regression analysis method, which is used for predicting the mixed ratio under different working conditions; S301, according to the speed and load interval and mixed ratio control parameter mapping table, the initial mixed ratio of natural gas and diesel oil corresponding to each interval is calculated.

5. The natural gas-diesel injection switching control system of a dual-fuel diesel engine according to claim 1, characterized by, According to the ideal gas state equation, the dynamic compensation of gas volume flow is carried out, and the specific process is as follows: S400, the real-time monitored pressure and temperature of the gas supply pipeline are obtained, the standard state definition and benchmark are determined, and the density value of the gas under the standard state is obtained from the gas composition analysis table; S401, the measured volume flow is compensated for pressure and temperature, and the actual mass flow of the gas under the actual state is calculated through the actual density of the gas; S402, the mass flow and the energy characteristics of the gas are combined to obtain the current low heat value of the gas, and the final real-time gas supply energy is calculated.

6. The natural gas-diesel injection switching control system of a dual-fuel diesel engine according to claim 1, characterized by, The optimal fuel replacement rate time sequence trajectory is generated, and the specific process is as follows: S500, the dynamic prediction model is constructed based on neural network, the model is initialized according to the actual characteristics and historical operation data of the engine, including the initial value of the model parameter, the network structure and the activation function; According to the related emission standard and the emission characteristics of the engine, the emission target function is constructed, which can usually be combined into a comprehensive emission index by using weighted summation method, the torque fluctuation of the engine is calculated, and the standard deviation or variance of the torque can be used to measure the stability of the torque, and the emission target function and the torque stability target function are combined into a multi-objective comprehensive optimization function; S501, taking the multi-objective comprehensive optimization function as the target, the optimal fuel replacement rate sequence is found in the feasible range of fuel replacement rate, which makes the value of the multi-objective comprehensive optimization function minimum, and the optimal fuel replacement rate time sequence trajectory is formed.

7. The natural gas-diesel injection switching control system of a dual-fuel diesel engine according to claim 1, characterized by, The gradual collaborative action of driving the dual fuel injector to execute diesel mode, dual fuel mode and switching between them is performed, and the specific process is as follows: S600, read the generated optimal fuel replacement rate time sequence trajectory data, analyze the fuel replacement rate time sequence trajectory, and determine the key time node of mode switching; S601, according to the performance of the engine and the control requirements of the dual fuel injector, a reasonable fuel replacement rate threshold is set, when the fuel replacement rate is less than the set diesel mode threshold, the diesel mode operation instruction is generated, when the fuel replacement rate is greater than the set dual fuel mode threshold, the dual fuel mode operation instruction is generated; S602, the corresponding diesel mode, dual fuel mode or transition mode operation instruction is generated, the operation instruction is arranged in time sequence to form an operation instruction sequence, and the operation instruction is sent and the dual fuel injector is driven to execute.

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