Engine speed control method, device, medium, and engine system

Abstract

The application provides a rotating speed control method, device, medium and engine system of an engine. The method comprises the following steps: obtaining a set rotating speed, a current actual rotating speed, a delay time influence rotating speed and a friction torque rotating speed mapping relationship of the engine. The friction torque rotating speed mapping relationship is a mapping relationship between the friction torque of the engine and the rotating speed of the engine. The delay time influence rotating speed represents the influence degree of the delay time of the engine on the rotating speed of the engine. According to the set rotating speed, the current actual rotating speed and the delay time influence rotating speed, the corrected rotating speed deviation is determined. According to the current actual rotating speed, the corrected rotating speed deviation and the friction torque rotating speed mapping relationship, the target indicated torque is determined by using the PID algorithm, and the engine is controlled to operate by using the target indicated torque, so as to adjust the rotating speed of the engine. Thus, the problem that the control effect is poor due to the neglect of the delay time and the friction torque in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine control, in particular to a method for controlling the speed of an engine, a device for controlling the speed of an engine, a computer readable storage medium and an engine system. BACKGROUND

[0002] In the existing field of speed control of premixed natural gas engines, the mainstream method is to use PID speed closed-loop control as the basis, and to realize accurate control of the engine speed by adjusting the fuel supply and the intake air volume. This control strategy relies on a feedback mechanism, taking the deviation between the set speed of the engine and the actual speed as input, and calculating the appropriate fuel and air ratio through a PID controller to generate the expected indicated torque, thereby achieving the purpose of speed regulation.

[0003] However, the traditional PID control method has the following two main technical defects:

[0004] Torque response delay is not fully considered: the torque generation process of a premixed natural gas engine is subject to various factors, including but not limited to the time delay of the intake process, the time delay of the combustion process, and the dynamic response delay of the control system. These delays result in a time difference between the actual indicated torque and the required indicated torque, usually exceeding 200 ms. In PID closed-loop control, this delay can reduce the phase margin, affecting the performance of the closed-loop control, causing the engine speed to fluctuate and jerk when facing load changes. In addition, when the phase lag caused by the delay and the control command are in phase, it may further exacerbate the system instability and reduce the speed control effect.

[0005] Neglect of friction torque influence: during engine operation, there is non-negligible friction torque due to contact friction between mechanical parts, viscous resistance of oil, and pumping loss. In existing technologies, friction torque is often considered as a constant disturbance or not considered separately, which directly leads to a decrease in the accuracy of speed control in steady state and a delay in dynamic response, and also causes unnecessary energy waste.

[0006] That is, the existing scheme ignores the influence of torque response delay and friction torque in the speed control of the engine, resulting in poor control effect of the engine speed. SUMMARY

[0007] The main purpose of the present application is to provide a method for controlling the speed of an engine, a device for controlling the speed of an engine, a computer readable storage medium and an engine system, to at least solve the problem that the existing scheme ignores the influence of torque response delay and friction torque in the speed control of the engine, resulting in poor control effect of the engine speed.

[0008] To achieve the above objectives, according to one aspect of this application, an engine speed control method is provided. The method includes: acquiring a set engine speed, a current actual engine speed, a time-delay-influenced speed, and a friction torque-speed mapping relationship, wherein the current actual engine speed is the actual engine speed at the current moment, the friction torque-speed mapping relationship is a mapping relationship between the engine's friction torque and the engine speed, and the time-delay-influenced speed represents the degree of influence of the engine's time delay on the engine speed; determining a corrected speed deviation based on the set engine speed, the current actual engine speed, and the time-delay-influenced speed; employing a PID algorithm to determine a target indicated torque based on the current actual engine speed, the corrected speed deviation, and the friction torque-speed mapping relationship, and using the target indicated torque to control the engine operation to adjust the engine speed.

[0009] Optionally, a PID algorithm is used to determine the target indicated torque based on the current actual speed, the corrected speed deviation, and the friction torque-speed mapping relationship. This includes: determining multiple friction torque coefficients using the least squares method based on the friction torque-speed mapping relationship; and determining the target indicated torque using the PID algorithm based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation.

[0010] Optionally, the method further includes: in the process of determining the target indicated torque using a PID algorithm based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation, determining the current friction torque based on all the friction torque coefficients and the current actual speed;

[0011] The target indicated torque is determined by using the PID algorithm based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation, including: determining the target indicated torque based on the corrected speed deviation and the current friction torque using the PID algorithm.

[0012] Optionally, determining the corrected speed deviation based on the set speed, the current actual speed, and the speed affected by the delay time includes: determining the speed difference as the difference between the set speed and the current actual speed; and determining the corrected speed deviation as the difference between the speed difference and the speed affected by the delay time.

[0013] Optionally, obtaining the effect of delay time on rotational speed includes: determining a first rotational speed based on the engine's moment of inertia, the indicated torque output by the PID controller at the current moment, and the friction torque-rotational speed mapping relationship; determining a second rotational speed based on the engine's moment of inertia, the indicated torque output by the PID controller at a delay time, and the friction torque-rotational speed mapping relationship, wherein the delay time is the difference between the current moment and the delay time; and determining that the effect of delay time on rotational speed is the difference between the first rotational speed and the second rotational speed.

[0014] Optionally, before obtaining the effect of the delay time on the engine speed, the method further includes: using a neural network model to determine the delay time based on the current actual engine speed and the intake air flow rate of the engine at the current moment.

[0015] Optionally, after determining the target indicated torque, the method further includes: if the target indicated torque is greater than or equal to a torque threshold, controlling the engine to stop running and generating a prompt message to indicate that the target indicated torque is greater than or equal to the torque threshold.

[0016] According to another aspect of this application, an engine speed control device is provided, the device comprising: an acquisition unit, configured to acquire a set engine speed, a current actual engine speed, a speed affected by a delay time, and a friction torque speed mapping relationship, wherein the current actual engine speed is the actual engine speed at the current moment, the friction torque speed mapping relationship is the mapping relationship between the engine's friction torque and the engine speed, and the speed affected by a delay time characterizes the degree of influence of the engine's delay time on the engine speed; a first determination unit, configured to determine a corrected speed deviation based on the set engine speed, the current actual engine speed, and the speed affected by a delay time; and a second determination unit, configured to use a PID algorithm to determine a target indicated torque based on the current actual engine speed, the corrected speed deviation, and the friction torque speed mapping relationship, and use the target indicated torque to control the engine operation to adjust the engine speed.

[0017] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform any of the methods described.

[0018] According to another aspect of this application, an engine system is provided, the system comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing any one of the methods described.

[0019] By incorporating the effect of time delay on engine speed using the technical solution of this application, the controller can consider the impact of time delay when calculating speed deviation, thereby making more timely and accurate adjustments during dynamic response. The utilization of the friction torque-speed mapping relationship allows for the prediction of the magnitude of the friction torque based on the current speed. This is then used to adjust the output of the PID controller via feedforward, offsetting the additional losses caused by the friction torque and ensuring the speed control accuracy in steady state. Therefore, this application can significantly improve the transient response speed, steady-state control accuracy, and stability of engine speed control, thus solving the problem of poor control performance caused by ignoring time delay and friction torque in existing solutions. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 A schematic flowchart of an engine speed control method according to an embodiment of this application is shown.

[0022] Figure 2 A schematic flowchart illustrating the determination of a target indicated torque according to an embodiment of this application is shown;

[0023] Figure 3 A flowchart illustrating the current premixed natural gas engine speed control method is shown.

[0024] Figure 4 A schematic diagram illustrating the principle of an engine speed control method according to an embodiment of this application is shown.

[0025] Figure 5 A schematic flowchart of another engine speed control method provided according to an embodiment of this application is shown;

[0026] Figure 6 A structural block diagram of an engine speed control device according to an embodiment of this application is shown. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] As introduced in the background section, traditional PID control methods have the following two main technical drawbacks:

[0031] Torque response delay is not adequately considered: The torque generation process of a premixed natural gas engine is constrained by various factors, including but not limited to the time delay of the intake process, the time delay of the combustion process, and the dynamic response delay of the control system. These delays result in a time difference between the actual indicated torque and the required indicated torque, typically exceeding 200ms. In PID closed-loop control, this delay leads to a reduction in phase margin, affecting closed-loop control performance and causing engine speed instability such as jitter and hesitation when facing load changes. Furthermore, when the phase lag caused by the delay is superimposed on the control command, it may further exacerbate system instability and reduce speed control effectiveness. Neglecting the influence of frictional torque: During engine operation, non-negligible frictional torque exists due to contact friction between mechanical parts, viscous resistance of engine oil, and pumping losses. In the prior art, frictional torque is often regarded as a constant disturbance or not considered separately, which directly leads to a decrease in the accuracy of speed control in steady state and a slow dynamic response. It also causes unnecessary energy waste. In order to solve the problem that the existing engine speed control ignores the influence of torque response delay and frictional torque, resulting in poor engine speed control, the embodiments of this application provide an engine speed control method, an engine speed control device, a computer-readable storage medium, and an engine system.

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] This embodiment provides a method for controlling the speed of an engine. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0034] Figure 1 This is a flowchart of an engine speed control method according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0035] Step S101: Obtain the engine's set speed, current actual speed, speed affected by delay time, and speed mapping relationship of friction torque. The current actual speed is the actual speed of the engine at the current moment. The speed mapping relationship of friction torque is the mapping relationship between the friction torque of the engine and the speed of the engine. The speed affected by delay time characterizes the degree of influence of the delay time of the engine on the speed of the engine.

[0036] The delay time has a non-linear relationship with engine speed. The magnitude of the delay time is not related to the speed. The delay time refers to the fact that the actual generated torque cannot keep up with the target torque demand in time. For example, if the demand is 100N, the engine may actually generate 100N after 0.3 seconds. This delay directly affects the torque control performance, and poor torque control performance will further lead to poor speed control performance.

[0037] Step S102: Determine the corrected speed deviation based on the set speed, the current actual speed, and the speed affected by the delay time.

[0038] Step S103: Using a PID algorithm, the target indicated torque is determined based on the current actual speed, the corrected speed deviation, and the friction torque-speed mapping relationship. The engine operation is then controlled using the target indicated torque to adjust the engine speed.

[0039] The PID algorithm, short for Proportional-Integral-Derivative Control, is a closed-loop control algorithm widely used in automatic control systems. It calculates the system's error signal and combines the actions of the proportional (P), integral (I), and derivative (D) components to adjust the output of actuators (such as valves and motors) to achieve stable control of process variables.

[0040] In the above steps, the introduction of the time delay effect on engine speed allows the controller to consider the impact of time delay when calculating speed deviation, thus enabling more timely and accurate adjustments during dynamic response. The utilization of the friction torque-speed mapping relationship allows for the prediction of the friction torque magnitude based on the current speed. By adjusting the PID controller output through feedforward, the additional losses caused by the friction torque are offset, ensuring the speed control accuracy in steady state. Therefore, this application can significantly improve the transient response speed, steady-state control accuracy, and stability of engine speed control, thereby solving the problem of poor control performance caused by ignoring time delay and friction torque in existing solutions.

[0041] In one embodiment of this application, such as Figure 2 As shown, the target indicated torque is determined using a PID algorithm based on the current actual speed, the corrected speed deviation, and the friction torque-speed mapping relationship. This includes the following steps:

[0042] Step S201: Determine multiple friction torque coefficients using the least squares method based on the above friction torque-speed mapping relationship;

[0043] Step S202: Using the PID algorithm described above, the target indicated torque is determined based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation.

[0044] This application also provides a first specific use case for determining the target indicated torque: a heavy-duty truck equipped with a premixed natural gas engine is about to depart for a long-distance transport mission. During the start-up and acceleration phases, the engine faces significant challenges: it not only needs to respond quickly to reach the predetermined speed, but also needs to cope with increased internal friction due to low temperatures. This poses a severe test to traditional speed control algorithms, potentially leading to slow speed response and increased fuel consumption.

[0045] Implementation Process: After the truck driver presses the start button, the engine control system is immediately activated. The system first acquires the current engine speed (assuming idle speed) and operating condition information (such as ambient temperature and engine temperature) through sensors. Next, using a pre-stored friction torque-speed mapping relationship and considering the increase in friction torque at low temperatures, the system calculates a set of friction torque coefficients suitable for the current operating conditions using the least squares method. After this, when the driver accelerates to a set speed, the system calculates the original deviation between the current actual speed and the set speed through real-time monitoring. However, due to the known existence of delay time and additional friction torque, the system does not directly control based on the original deviation. Instead, it first applies a compensation strategy for the impact of delay time on speed to correct the speed deviation, and then considers the influence of the friction torque coefficient, using a PID algorithm to dynamically adjust the target indicated torque to overcome the negative impact of friction torque and delay time on the speed control effect.

[0046] The beneficial effects of determining the target indicated torque in the first specific application scenario are as follows: Even in harsh environments, such as cold starts, the engine speed can reach the driver's desired set value more quickly because the system can correct speed deviations caused by delay time and frictional torque in real time. This avoids the speed "climbing" phenomenon common in traditional control methods, improving vehicle starting efficiency and driving comfort. Through more precise torque control, the engine can reach its optimal operating state in a shorter time, reducing unnecessary fuel waste. Especially during cold starts and frequent acceleration and deceleration, this precise control can significantly improve energy efficiency and reduce operating costs. Accurate compensation for frictional torque means reduced additional stress on internal engine components, lowering wear and failure rates. This not only extends engine lifespan but also reduces maintenance frequency, saving costs for users. Whether in high-temperature, high-cold, or extreme humidity environments, the speed control strategy of this invention can be flexibly adjusted to ensure engine performance is unaffected by external conditions, improving the overall reliability of the vehicle. This is particularly important for heavy-duty trucks that need to operate in various harsh environments.

[0047] In one embodiment of this application, the method further includes: in the process of determining the target indicated torque by employing a PID algorithm based on all the friction torque coefficients, the current actual speed and the corrected speed deviation, determining the current friction torque based on all the friction torque coefficients and the current actual speed;

[0048] Using the PID algorithm described above, the target indicated torque is determined based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation. This includes: using the PID algorithm described above, the target indicated torque is determined based on the corrected speed deviation and the current friction torque.

[0049] This application also provides a second specific use case for determining the target indicated torque: a bus using a premixed natural gas engine is navigating through busy urban traffic, frequently accelerating and decelerating. Under such operating conditions, the engine needs to quickly adapt to constantly changing loads. Simultaneously, due to the vehicle's daily operation, the frictional torque within the engine may also change with time and operating conditions, placing higher demands on the precision and efficiency of speed control.

[0050] Implementation Process: When a bus driver accelerates through a busy intersection, the engine control system responds immediately. The control system first calculates the current friction torque in real time based on the current engine speed and a pre-stored friction torque-speed mapping relationship, combined with multiple friction torque coefficients determined using the least squares method. This process ensures that the controller can instantly understand and compensate for changes in friction torque caused by factors such as engine component wear and oil viscosity variations, providing a foundation for precise control. After determining the current friction torque, the system uses a PID algorithm, considering not only the corrected speed deviation but also the actual value of the current friction torque, to dynamically adjust the target indicated torque. This means that even in environments with changing friction torque, the controller can ensure the accuracy of the target indicated torque through feedforward compensation, thereby accurately controlling the engine speed to quickly respond to acceleration commands while maintaining a set steady-state speed, reducing unnecessary fuel consumption and emissions.

[0051] The beneficial effects of determining the target indicated torque in the second specific application scenario are as follows: Because the controller can adjust according to the real-time friction torque, even in scenarios of rapid acceleration or complex load changes, the engine can quickly reach and stabilize at the required speed, improving vehicle acceleration and driving smoothness; by accurately assessing and compensating for friction torque, the engine can use fuel more efficiently during acceleration, avoiding additional power loss caused by increased friction torque. This is particularly important in urban bus operations with frequent acceleration and deceleration, helping to reduce operating costs and improve energy efficiency; more precise torque control and fuel supply strategies reduce unnecessary fuel consumption, thereby reducing vehicle emissions and contributing positively to improving urban air quality and promoting green transportation; rapid and smooth acceleration performance not only improves passenger comfort but also reduces potential traffic safety risks caused by uneven acceleration, improving overall operational safety; accurate compensation for friction torque means reduced additional stress on internal engine components, slower wear, thus extending engine maintenance cycles and reducing maintenance costs.

[0052] In one embodiment of this application, determining the corrected speed deviation based on the set speed, the current actual speed, and the speed affected by the delay time includes: determining the speed difference as the difference between the set speed and the current actual speed; and determining the corrected speed deviation as the difference between the speed difference and the speed affected by the delay time.

[0053] Specifically, by determining the corrected speed deviation—that is, the actual speed deviation after considering the effect of the delay time—the control system can more accurately assess the instantaneous adjustment required for the engine to reach the set speed. Under dynamic conditions (such as acceleration or deceleration), this correction helps the controller respond more quickly, reducing the time it takes for the speed to reach the set value, thereby improving the engine's dynamic response performance and ensuring a smoother driving experience. When the engine is operating in a steady state, the presence of the delay time affecting the speed can cause deviations between the output of a traditional PID controller and actual needs, resulting in speed fluctuations. The method of this invention, by correcting the speed deviation, can eliminate or significantly reduce this delay effect, enabling the engine to operate more stably after reaching the set speed, reducing speed fluctuations, and improving steady-state control accuracy. Considering the effect of the delay time on the speed, the control strategy can more precisely adjust the fuel and air supply, avoiding over-compensation or under-compensation. This not only reduces fuel waste but also improves combustion efficiency and lowers the overall energy consumption of the engine, which is of great significance for improving the vehicle's economy and environmental friendliness. Precise speed control helps optimize the engine's combustion process, reducing incomplete combustion and the formation of harmful substances, thereby reducing emissions. This has a significant positive impact on meeting increasingly stringent emission standards and reducing environmental pollution. By correcting speed deviations, the control system can better cope with uncertainties under various operating conditions, such as load changes and temperature variations, thus enhancing its robustness. Even under complex and variable operating conditions, it can maintain high control performance and stability, reducing the risk of engine failure.

[0054] In one embodiment of this application, obtaining the speed affected by the delay time includes: determining a first speed based on the engine's moment of inertia, the indicated torque output by the PID controller at the current moment, and the friction torque-speed mapping relationship; determining a second speed based on the engine's moment of inertia, the indicated torque output by the PID controller at a delay time, and the friction torque-speed mapping relationship, wherein the delay time is the difference between the current moment and the delay time; and determining that the speed affected by the delay time is the difference between the first speed and the second speed.

[0055] Specifically, by precisely quantifying the instantaneous impact of delay time on engine speed, the control system can compensate for this impact as an additional source of error in subsequent PID algorithm calls. This allows for more accurate and timely adjustment of the actual output indicated torque to achieve the expected speed. This significantly improves the engine's transient response speed to load changes, especially under conditions requiring rapid acceleration or deceleration, enhancing vehicle handling and safety. During steady-state operation, accurate calculation of the delay time's impact on speed helps eliminate small but persistent speed deviations caused by signal delays and engine dynamic response characteristics, ensuring the engine operates stably at the set speed point over a long period, reducing speed fluctuations and improving the overall control accuracy of the system. Reduced speed fluctuations and improved response speed mean the engine can maintain efficient operation over a wider operating range, avoiding unnecessary fuel waste and helping to reduce emissions under non-ideal operating conditions, thus contributing positively to environmental protection and energy conservation. Precise speed control reduces the additional stress on internal engine components caused by excessive or uneven load changes, helping to reduce mechanical wear, extend engine maintenance cycles and service life, and lower long-term operating costs.

[0056] In one embodiment of this application, before obtaining the effect of the delay time on the rotational speed, the method further includes: using a neural network model to determine the delay time based on the current actual rotational speed and the intake air flow of the engine at the current moment.

[0057] Specifically, neural network models possess self-learning and adaptive capabilities, enabling them to learn the complex nonlinear relationships between delay time and these variables based on extensive historical data and real-time operating conditions (such as current actual engine speed and engine intake airflow). This means that even under constantly changing engine operating conditions, neural networks can accurately predict delay time, ensuring the control system can make timely adjustments and improving adaptability and flexibility. Traditional delay time prediction methods are often based on empirical formulas or simplified models, which may not fully account for all influencing factors, leading to significant errors in prediction results. Neural networks, however, can handle high-dimensional, nonlinear data relationships. Through training, they can capture the impact of more subtle changes in operating conditions on delay time, thereby improving prediction accuracy and reducing control deviations caused by prediction errors. Once trained, the neural network model can be input in real-time with data such as current actual engine speed and intake airflow, quickly outputting predicted delay time values ​​and providing rapid feedback for the immediate adjustment of the speed control system. This is crucial for coping with rapidly changing loads or driving conditions (such as acceleration and deceleration), ensuring the control system responds quickly, reducing speed fluctuations, and improving driving smoothness and safety.

[0058] In addition to using neural network models, the delay time can also be determined by using a mapping table of rotational speed, intake flow rate, and delay time.

[0059] In one embodiment of this application, after determining the target indicated torque, the method further includes: controlling the engine to stop running when the target indicated torque is greater than or equal to a torque threshold, and generating a prompt message to indicate that the target indicated torque is greater than or equal to the torque threshold.

[0060] Specifically, engines are designed and manufactured with specific torque limits. Exceeding these limits can cause excessive stress on internal components, leading to damage or even failure of critical components such as pistons, crankshafts, and connecting rods. Immediately stopping the engine when the target indicated torque reaches or exceeds the torque threshold can effectively prevent such mechanical damage, ensure engine health, and extend its service life. In some cases, excessive torque output can cause safety problems such as tire slippage and loss of vehicle control, especially on wet or icy roads. By promptly stopping the engine and alerting the driver, safety accidents caused by excessive torque can be avoided, protecting the lives of the driver and passengers while reducing property damage. When the target indicated torque is higher than necessary, it often means excessive fuel supply. This measure not only avoids mechanical damage but also reduces fuel waste by preventing unnecessary high torque output, directly improving the fuel economy of vehicles or equipment and reducing operating costs.

[0061] like Figure 3 The diagram illustrates a current premixed natural gas engine speed control method primarily based on a PID closed-loop speed control system. The main steps are as follows: First, the actual engine speed is subtracted from the set engine speed to obtain the speed deviation. Then, this speed deviation is fed into the PID controller, which calculates the engine's required torque based on the deviation. Subsequently, the engine adjusts the air and fuel quantities according to the required torque, generating the actual indicated torque through combustion, thereby driving the engine and its load to achieve the actual engine speed. While the above method is relatively simple in concept, it neglects the influence of several key factors during the design process.

[0062] Due to time delays in the intake and combustion processes, as well as dynamic response delays in the control system, premixed engines cannot quickly generate the actual indicated torque based on the demand-indicated torque. There is typically a delay of over 200ms between the issuance of the demand-indicated torque command and the generation of the actual indicated torque. In closed-loop speed control, this delay leads to a decrease in phase margin, deterioration of closed-loop control performance, and adverse reactions such as engine speed fluctuations and jerking. Furthermore, the phase lag caused by the delay may cause the controller output to be superimposed on the disturbance, further exacerbating instability.

[0063] Due to factors such as contact friction of mechanical parts, oil viscosity resistance, and pumping losses, frictional torque inevitably exists during engine operation. If not addressed specifically, frictional torque can lead to a decrease in steady-state accuracy of speed control, lag in dynamic response, and additional energy efficiency losses.

[0064] This application establishes a speed control model for a premixed natural gas engine that considers torque response delay and the influence of frictional torque: Based on Newton's second law, and considering the influence of torque response delay and frictional torque, the dynamic model of the premixed natural gas engine can be established as follows:

[0065] ;

[0066] This is the derivative of the engine speed. Let U(t-τ) be the load torque of the attachment, U(t-τ) be the engine demand indicated torque calculated by the PID controller at time t-τ, and J be the engine moment of inertia. The speed can be obtained by integrating the derivative of the speed with respect to the speed. Considering various frictional effects such as static friction and dynamic friction, the frictional torque can be modeled as follows:

[0067] ;

[0068] Where a, b, and c are constant coefficients (i.e., friction torque coefficients). In summary, the following dynamic model of the premixed natural gas engine can be obtained:

[0069] ;

[0070] The transfer function characterizes the relationship between the PID input t-τ and the speed output ω of the premixed natural gas engine in the time domain.

[0071] Torque response delay time identification (based on a delay predictor compensation mechanism): The torque response delay time τ cannot be obtained in advance and must be identified offline. Experimental research and test data show that the torque response delay time τ is related to engine speed ω and engine intake airflow. There is a significant correlation. Based on this correlation, τ can be modeled as the relationship between ω and flow rate. The bivariate functional relationship τ = f(ω, Φ) is given. To obtain the full-condition model, the engine is tested under full-condition conditions in open-loop control mode, and the data are collected. Test data under different speeds and intake flow rates ( ) ,Right now:

[0072] ;

[0073] Based on the above experimental data, a MAP-form model of the delay time τ can be obtained, where the x-axis of the MAP represents the engine speed ω and the y-axis represents the engine intake airflow. During actual engine operation, the torque response delay time τ under the corresponding operating conditions can be obtained by consulting this MAP.

[0074] Friction torque coefficient identification: The friction torque coefficients (a, b, c) cannot be obtained in advance, but can be identified as follows. First, shut off the natural gas supply to the engine, and use an electric dynamometer to drive the engine, measuring the driving torque at different speeds. At this time, the driving torque is equal to the engine's friction torque, thus obtaining n sets of speed-friction torque data (a, b, c). Then, based on the collected data, the following matrix equations were constructed for the friction torque and friction torque coefficients (a, b, c):

[0075] ;

[0076] By solving the above set of equations using the least squares method, the friction torque coefficients (a, b, c) can be obtained by fitting.

[0077] Based on the identification of friction torque and torque response delay time, a PID speed controller with friction torque feedforward compensation and torque response delay time processing is designed.

[0078] First, a delay predictor is designed to predict the impact of torque response delay online and provide real-time compensation to eliminate the influence of delay time on the control system, thereby improving speed control performance and stability. Specifically, the engine speed without delay time is first calculated according to the following equation:

[0079] ;

[0080] in, The engine speed without delay. U(t) is the derivative of the engine speed without delay, and U(t) is the engine demand indicated torque calculated by the PID controller at time t.

[0081] Then, the engine speed with a time delay is calculated according to the following equation:

[0082] ;

[0083] in, The engine speed with a time delay. This is the derivative of the engine speed with a time delay.

[0084] Therefore, the effect of the delay time on the engine speed can be calculated as follows:

[0085] ;

[0086] in, Characterize the effect of delay time on rotational speed.

[0087] Based on this, the rotational speed deviation corrected for the effect of delay time can be calculated:

[0088] ;

[0089] in, For speed deviation, To set the rotation speed, This refers to the actual rotational speed; This is the speed deviation corrected based on the effect of delay time.

[0090] In summary, a PID speed controller with friction torque feedforward compensation and torque response delay time processing can be designed as follows:

[0091] ;

[0092] Where, k p k i k d Here, represents the PID coefficients, and U(t) is the output of the PID controller at the current time t. By processing the torque response time and compensating for friction torque feedforward, the adverse effects of time delay and friction on speed control performance can be eliminated simultaneously, improving the performance and stability of speed control.

[0093] Control method implementation: First, based on Figure 4 The control framework shown is used to write the code program for the proposed method; then, the code program is flashed into the engine controller, i.e., the ECU (Electronic Control Unit, which is used to manage and control different electronic systems, such as engine management, transmission control, airbag system, etc.), to realize the actual operation of the proposed method in a real vehicle.

[0094] This paper addresses the impact of torque response delay by providing prediction and compensation. Existing technologies neglect the influence of torque response delay. However, due to time delays in the intake, combustion, and control systems, premixed engines inevitably experience torque response delay. Ignoring this delay can lead to adverse effects such as engine speed fluctuations and jerking. In contrast, this application explicitly considers the existence of torque response delay during the system modeling stage and provides a method for identifying this delay. Based on this, a predictor is designed to predict the impact of torque response delay online and provides real-time compensation, eliminating the impact of the delay on the control system and improving the transient response speed, steady-state control accuracy, and stability of speed control.

[0095] Considering the influence of frictional torque and providing feedforward compensation: Existing technologies only rely on PID speed closed-loop control to achieve speed control, neglecting the impact of frictional torque, such as contact friction of mechanical components, oil viscous resistance, and pumping losses. This easily leads to decreased steady-state accuracy of speed control, lag in dynamic response, and additional energy efficiency losses. In contrast, this application considers the influence of frictional torque, establishes a model of frictional torque, and provides a method for identifying the frictional torque coefficient. Based on this, feedforward compensation for frictional torque is implemented, eliminating the adverse response of frictional torque to the closed-loop control system.

[0096] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the engine speed control method of this application will be described in detail below with reference to specific embodiments.

[0097] This embodiment relates to a specific engine speed control method, such as... Figure 5 As shown, it includes:

[0098] The system acquires the engine's set speed, current actual speed, the speed affected by delay time, and the speed mapping relationship between friction torque and speed. Specifically, a first speed is determined based on the engine's moment of inertia, the indicated torque output by the PID controller at the current moment, and the speed mapping relationship between friction torque and speed. A second speed is determined based on the engine's moment of inertia, the indicated torque output by the PID controller at a delay time, and the speed mapping relationship between friction torque and speed. The speed affected by delay time is determined as the difference between the first and second speeds. The current actual speed is the engine's actual speed at the current moment. The speed mapping relationship between friction torque and speed represents the mapping relationship between the engine's friction torque and engine speed. The speed affected by delay time characterizes the degree of influence of the engine's delay time on its speed.

[0099] The speed difference is determined to be the difference between the set speed and the current actual speed; the corrected speed deviation is determined to be the difference between the speed difference and the speed affected by the delay time.

[0100] Multiple friction torque coefficients are determined using the least squares method based on the friction torque-speed mapping relationship.

[0101] The target indicated torque is determined by using a PID algorithm based on the corrected speed deviation and the current friction torque.

[0102] The engine is controlled by a target indicated torque to regulate the engine speed.

[0103] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0104] This application also provides an engine speed control device. It should be noted that the engine speed control device of this application embodiment can be used to execute the engine speed control method provided in this application embodiment. This device is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0105] The following describes the engine speed control device provided in the embodiments of this application.

[0106] Figure 6 This is a schematic diagram of an engine speed control device according to an embodiment of this application. Figure 6 As shown, the device includes:

[0107] The acquisition unit 61 is used to acquire the engine's set speed, current actual speed, speed affected by delay time, and speed mapping relationship of friction torque. The current actual speed is the actual speed of the engine at the current moment. The speed mapping relationship of friction torque is the mapping relationship between the engine's friction torque and the engine's speed. The speed affected by delay time characterizes the degree of influence of the engine's delay time on the engine's speed. The first determination unit 62 is used to determine the corrected speed deviation based on the set speed, the current actual speed, and the speed affected by delay time. The second determination unit 63 is used to use a PID algorithm to determine the target indicated torque based on the current actual speed, the corrected speed deviation, and the speed mapping relationship of friction torque, and to use the target indicated torque to control the engine operation to adjust the engine speed.

[0108] In the aforementioned device, the introduction of time delay to influence engine speed allows the controller to consider the impact of time delay when calculating speed deviation, thereby enabling more timely and accurate adjustments during dynamic response. The utilization of the friction torque-speed mapping relationship allows for the prediction of the friction torque magnitude based on the current speed. By adjusting the PID controller output through feedforward, the additional losses caused by the friction torque are offset, ensuring steady-state speed control accuracy. Therefore, this application significantly improves the transient response speed, steady-state control accuracy, and stability of engine speed control, thus solving the problem of poor control performance caused by neglecting time delay and friction torque in existing solutions.

[0109] In one embodiment of this application, the second determining unit includes: a first processing module for determining multiple friction torque coefficients based on the friction torque-speed mapping relationship using the least squares method; and a second processing module for determining the target indicated torque based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation using the PID algorithm described above.

[0110] In one embodiment of this application, the above-mentioned device further includes: a third determining unit configured to determine the current friction torque based on all the above-mentioned friction torque coefficients and the current actual speed during the process of determining the target indicated torque using a PID algorithm based on all the above-mentioned friction torque coefficients, the current actual speed and the corrected speed deviation;

[0111] The second processing module includes: the processing module is used to determine the target indicated torque by using the above-mentioned PID algorithm, based on the above-mentioned corrected speed deviation and the above-mentioned current friction torque.

[0112] In one embodiment of this application, the first determining unit includes: a third processing module for determining the speed difference as the difference between the set speed and the current actual speed; and determining the corrected speed deviation as the difference between the speed difference and the speed affected by the delay time.

[0113] In one embodiment of this application, the acquisition unit includes: a fourth processing module for determining a first rotational speed based on the engine's rotational inertia, the indicated torque output by the PID controller at the current moment, and the friction torque-speed mapping relationship; a fifth processing module for determining a second rotational speed based on the engine's rotational inertia, the indicated torque output by the PID controller at a delayed moment, and the friction torque-speed mapping relationship, wherein the delayed moment is the difference between the current moment and the delayed time; and a sixth processing module for determining that the delayed time affects the rotational speed as the difference between the first rotational speed and the second rotational speed.

[0114] In one embodiment of this application, the above-mentioned device further includes: a first processing unit for determining the delay time by using a neural network model, based on the current actual speed and the intake air flow of the engine at the current moment, before acquiring the effect of the delay time on the rotational speed.

[0115] In one embodiment of this application, the device further includes: a second processing unit configured to, after determining the target indicated torque, control the engine to stop running if the target indicated torque is greater than or equal to a torque threshold, and generate a prompt message to indicate that the target indicated torque is greater than or equal to the torque threshold.

[0116] The aforementioned engine speed control device includes a processor and a memory. The aforementioned acquisition unit, first processing unit, and second processing unit are all stored as program units in the memory, and the processor executes the aforementioned program units stored in the memory to achieve the corresponding functions. All of the aforementioned modules are located in the same processor; alternatively, the aforementioned modules may be located in different processors in any combination.

[0117] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured. By adjusting kernel parameters, the problem of poor engine speed control in existing solutions—which ignores the effects of torque response delay and friction torque—can be addressed.

[0118] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0119] This invention provides a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the engine speed control method.

[0120] This invention provides a processor for running a program, wherein the program executes the engine speed control method.

[0121] This invention provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps: acquiring a set engine speed, a current actual engine speed, a speed affected by a delay time, and a speed-friction torque mapping relationship; wherein the current actual engine speed is the actual engine speed at the current moment, the friction torque-speed mapping relationship is the mapping relationship between the engine's friction torque and its speed, and the speed affected by a delay time characterizes the degree of influence of the engine's delay time on its speed; determining a corrected speed deviation based on the set engine speed, the current actual engine speed, and the speed affected by a delay time; and using a PID algorithm to determine a target indicated torque based on the current actual engine speed, the corrected speed deviation, and the friction torque-speed mapping relationship, and using the target indicated torque to control the engine operation to adjust the engine speed. The device described herein can be a server, PC, PAD, mobile phone, etc.

[0122] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps: acquiring the engine's set speed, current actual speed, speed affected by delay time, and friction torque speed mapping relationship, wherein the current actual speed is the engine's actual speed at the current moment, the friction torque speed mapping relationship is the mapping relationship between the engine's friction torque and the engine's speed, and the speed affected by delay time characterizes the degree of influence of the engine's delay time on the engine's speed; determining a corrected speed deviation based on the set speed, the current actual speed, and the speed affected by delay time; employing a PID algorithm to determine a target indicated torque based on the current actual speed, the corrected speed deviation, and the friction torque speed mapping relationship, and using the target indicated torque to control the engine operation to adjust the engine speed.

[0123] This application also provides an engine system comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include methods for performing any of the methods described above. The introduction of the effect of time delay on engine speed allows the controller to consider the effect of time delay when calculating speed deviation, thereby making more timely and accurate adjustments during dynamic response. The utilization of the friction torque-speed mapping relationship allows the magnitude of the friction torque to be predicted based on the current speed, and the output of the PID controller can be adjusted by feedforward to offset the additional losses caused by the friction torque, ensuring the speed control accuracy in steady state. Therefore, this application can significantly improve the transient response speed, steady-state control accuracy, and stability of engine speed control, thereby solving the problem of poor control performance caused by ignoring time delay and friction torque in existing solutions.

[0124] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0125] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0126] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0127] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0128] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0129] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0130] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0131] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0132] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0134] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for controlling the speed of an engine, characterized in that, include: The engine's set speed, current actual speed, speed affected by delay time, and speed mapping relationship of friction torque are obtained. The current actual speed is the actual speed of the engine at the current moment. The speed mapping relationship of friction torque is the mapping relationship between the friction torque of the engine and the speed of the engine. The speed affected by delay time characterizes the degree of influence of the engine's delay time on the engine's speed. Based on the set rotational speed, the current actual rotational speed, and the effect of the delay time on the rotational speed, the corrected rotational speed deviation is determined; A PID algorithm is used to determine the target indicated torque based on the current actual speed, the corrected speed deviation, and the friction torque-speed mapping relationship. The target indicated torque is then used to control the engine operation in order to adjust the engine speed.

2. The method according to claim 1, characterized in that, Using a PID algorithm, the target indicated torque is determined based on the current actual speed, the corrected speed deviation, and the friction torque-speed mapping relationship, including: Multiple friction torque coefficients are determined using the least squares method based on the aforementioned friction torque-speed mapping relationship. The target indicated torque is determined using the PID algorithm based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation.

3. The method according to claim 2, characterized in that, The method further includes: in the process of determining the target indicated torque using a PID algorithm based on all the friction torque coefficients, the current actual speed and the corrected speed deviation, determining the current friction torque based on all the friction torque coefficients and the current actual speed; The target indicated torque is determined by using the PID algorithm based on all the friction torque coefficients, the current actual speed, and the corrected speed deviation, including: determining the target indicated torque based on the corrected speed deviation and the current friction torque using the PID algorithm.

4. The method according to claim 1, characterized in that, Based on the set rotational speed, the current actual rotational speed, and the effect of the delay time on the rotational speed, the corrected rotational speed deviation is determined, including: The speed difference is determined to be the difference between the set speed and the current actual speed; The corrected rotational speed deviation is determined to be the difference between the rotational speed difference and the effect of the delay time on the rotational speed.

5. The method according to claim 1, characterized in that, The effect of latency on rotational speed includes: The first rotational speed is determined based on the engine's moment of inertia, the indicated torque output by the PID controller at the current moment, and the frictional torque-rotational speed mapping relationship. The second rotational speed is determined based on the engine's moment of inertia, the indicated torque output by the PID controller at the delay time, and the friction torque-speed mapping relationship, wherein the delay time is the difference between the current time and the delay time. The effect of the delay time on the rotational speed is determined to be the difference between the first rotational speed and the second rotational speed.

6. The method according to claim 1, characterized in that, Before determining the effect of the delay time on the rotational speed, the method further includes: A neural network model is used to determine the delay time based on the current actual speed and the intake air flow of the engine at the current moment.

7. The method according to any one of claims 1 to 6, characterized in that, After determining the target indicated torque, the method further includes: If the target indicated torque is greater than or equal to the torque threshold, the engine is controlled to stop running, and a prompt message is generated to indicate that the target indicated torque is greater than or equal to the torque threshold.

8. An engine speed control device, characterized in that, include: The acquisition unit is used to acquire the engine's set speed, current actual speed, speed affected by delay time, and speed mapping relationship of friction torque. The current actual speed is the actual speed of the engine at the current moment. The speed mapping relationship of friction torque is the mapping relationship between the engine's friction torque and the engine's speed. The speed affected by delay time characterizes the degree of influence of the engine's delay time on the engine's speed. The first determining unit is used to determine the corrected speed deviation based on the set speed, the current actual speed, and the speed affected by the delay time; The second determining unit is used to use a PID algorithm to determine a target indicated torque based on the current actual speed, the corrected speed deviation, and the friction torque-speed mapping relationship, and to use the target indicated torque to control the engine operation in order to adjust the engine speed.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 7.

10. An engine system, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising methods for performing any one of claims 1 to 7.

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