A system and method for calibrating the time constant of a diesel engine electronic speed control system

Abstract

The present invention relates to a system and method for calibrating the time constant of a diesel engine electronic speed control system. The system comprises: a drive current sensor for acquiring real-time drive current data; a rack displacement sensor for acquiring real-time rack displacement data; a cylinder gas pressure sensor for acquiring changes in gas pressure within the cylinder and obtaining dynamometer diagram data for single-cylinder power calculation; and a high-pressure oil pipe pressure sensor for acquiring real-time fuel pressure data. The drive current sensor, rack displacement sensor, cylinder gas pressure sensor, and high-pressure oil pipe pressure sensor are connected to a synchronous data acquisition unit, and the transfer function and time constant of the electronic speed control system are determined by analyzing the phase difference of each signal data. The present invention can quickly obtain the time constant of the speed control system without relying on the structural parameter data of the diesel engine. This provides an effective technical means for on-site tuning of the PID control parameters of the diesel engine speed control system, thereby ensuring the stable operation of the diesel engine.

Description

Technical Field

[0001] The present invention relates to a design technology of a diesel engine electronic speed control system, and in particular to a system and method for calibrating a time constant of a diesel engine electronic speed control system based on synchronous test data of a driving current and a diesel engine cylinder pressure. Background Art

[0002] A diesel engine converts chemical energy into mechanical energy. Fuel burns within the combustion chamber, releasing energy during the combustion process. Part of this energy is transferred to the enclosed gases within the combustion chamber, increasing their temperature and pressure. Part of this energy increases the temperature of the surrounding heated components and is dissipated through the cooling system into the coolant or air. The heat release rate during combustion is governed by a variety of factors, most notably the intake air volume, fuel injection rate, and the temperature of the combustion chamber's heated components. The intake air volume is affected by the local atmospheric pressure and the turbocharger's operating state; the fuel injection rate is influenced by the fuel injection pressure and the rack displacement of the high-pressure fuel pump; and the temperature of the combustion chamber's heated components is affected by the engine's operating time and the cooling system's circulating fluid flow rate and temperature. Consequently, due to these complex factors, diesel engine operating characteristics exhibit typical nonlinear and time-varying characteristics, making their dynamics difficult to represent using specific transfer functions.

[0003] The diesel engine electronic speed control system consists of a controller and an actuator. The controller's working goal is to control the diesel engine to run at a set speed. By collecting the difference between the actual speed of the diesel engine and the set speed as a control error signal, the PID control method is used to adjust the output current of the actuator according to the value of the speed error, thereby changing the output displacement of the actuator. The actuator is connected to the rack of the diesel engine's high-pressure oil pump. By changing the output displacement, the fuel injection amount of the diesel engine is changed to achieve diesel engine speed regulation.

[0004] When the diesel engine electronic speed governor controls the operation of the diesel engine, it is necessary to adjust the specific values ​​of the PID control parameters to ensure that the diesel engine can operate stably under all working conditions. The adjustment of the PID control parameters requires obtaining the lag time constant between the diesel engine power change and the controller drive current change as basic data. The traditional method is to establish a diesel numerical simulation model and determine this lag time constant through complex simulation calculation and analysis. Due to the nonlinearity and time variability of the diesel engine, the calibration of the diesel engine numerical simulation model requires a large number of diesel engine structural parameters and an accurate combustion model. At the same time, it is also necessary to obtain test data such as the friction loss work and pumping loss work of the diesel engine, and to obtain the data of the overall rotational inertia of the diesel engine through experiments, which is very difficult to achieve. Summary of the Invention

[0005] The purpose of the present invention is to address the problems existing in the prior art and provide a speed control system time constant calibration system and method that does not rely on diesel engine structural parameters and performance parameters, but only relies on control system drive current and diesel engine cylinder pressure synchronization test data.

[0006] The technical solution of the present invention is as follows: A system for calibrating the time constant of a diesel engine electronic speed control system, comprising:

[0007] The driving current sensor is connected to the driving unit output of the electronic speed regulator controller to obtain real-time data of the driving current;

[0008] The rack displacement sensor is connected to the diesel engine oil pump rack to obtain real-time data on rack displacement;

[0009] The cylinder gas pressure sensor is connected to the combustion chamber of the diesel engine cylinder to collect the gas pressure changes in the cylinder and obtain the dynamometer data for single-cylinder power calculation;

[0010] High-pressure fuel pipe pressure sensor, connected to the high-pressure fuel pipe to obtain real-time data of fuel pressure;

[0011] The driving current sensor, rack displacement sensor, cylinder gas pressure sensor, and high-pressure oil pipe pressure sensor are respectively connected to a synchronous data acquisition unit. The synchronous data acquisition unit synchronously collects input signal data of each sensor in time, and determines the transfer function and time constant of the electronic speed control system by analyzing the phase difference of each signal data.

[0012] Furthermore, in the above-mentioned calibration system for the time constant of the diesel engine electronic speed control system, the drive cable of the electronic speed controller is connected to the drive coil of the electronic speed controller actuator, and the drive current sensor is connected in series in the output circuit of the drive cable of the electronic speed controller.

[0013] Furthermore, in the above-mentioned diesel engine electronic speed control system time constant calibration system, the rack displacement sensor is rigidly connected to the free end of the electronic speed controller actuator drive shaft, and the drive end of the drive shaft is rigidly connected to the rack of the diesel engine oil pump.

[0014] Furthermore, in the above-mentioned diesel engine electronic speed control system time constant calibration system, the high-pressure oil pipe pressure sensor is connected to the high-pressure oil pipe through a clamping flange, and the connection position is close to the injector.

[0015] Furthermore, in the above-mentioned diesel engine electronic speed control system time constant calibration system, the cylinder gas pressure sensor is connected to the combustion chamber of the diesel engine cylinder through a thread, and the sensitive element of the cylinder gas pressure sensor is in direct contact with the gas in the cylinder.

[0016] A calibration method using the above diesel engine electronic speed control system time constant calibration system comprises:

[0017] (1) The synchronous data acquisition unit synchronously collects real-time signal data of the driving current sensor, rack displacement sensor, cylinder gas pressure sensor, and high-pressure oil pipe pressure sensor;

[0018] (2) Based on the driving current and rack displacement signal data, determine the phase lag of the rack displacement relative to the driving current and calibrate the actuator transfer function;

[0019] (3) Based on the rack displacement and the in-cylinder gas pressure signal data, the phase lag of the single-cylinder power change relative to the rack displacement is determined, and the high-pressure oil pump transfer function and the cylinder unit transfer function are calibrated;

[0020] (4) Determine the time constant of the diesel engine electronic speed control system using the transfer function calibrated in steps (2) and (3).

[0021] Furthermore, in the above-mentioned method for calibrating the time constant of the diesel engine electronic speed control system, the signal data of the driving current sensor is used as a reference input signal for time constant calibration and as a direct input of the actuator transfer function;

[0022] The signal data of the rack displacement sensor is used as the function output of the actuator transfer function and as the direct input of the high-pressure oil pump transfer function;

[0023] The signal data of the high-pressure oil pipe pressure sensor is used as a function output of the high-pressure oil pump transfer function and as a direct input of the cylinder unit transfer function;

[0024] The signal data of the cylinder gas pressure sensor is output as a function of the cylinder unit transfer function.

[0025] Furthermore, in the above-mentioned method for calibrating the time constant of the diesel engine electronic speed control system, the actuator transfer function is in the form of X=F(I), where X is the rack displacement of the high-pressure oil pump, and I is the driving current of the electronic speed governor controller. When the driving current I changes, the inductance of the actuator drive coil changes, generating an electromagnetic force to drive the position of the high-pressure oil pump rack to change; the time constant of X=F(I) is expressed as τ1, which is determined by the phase between the signal I of the driving current sensor and the displacement X of the rack displacement sensor, and the time constant τ1=t2-t1, where t1 is the starting time of the driving current sensor signal and t2 is the starting time of the rack displacement sensor signal.

[0026] Furthermore, in the above-described method for calibrating the time constant of the diesel engine electronic speed control system, the high-pressure fuel pump transfer function is P1=F(X), where X is the rack displacement of the high-pressure fuel pump and P1 is the signal of the high-pressure fuel line pressure sensor. When the rack displacement X of the high-pressure fuel pump changes, the cyclic injection amount is controlled by changing the profile of the high-pressure fuel pump plunger coupling. The characteristic parameter of the cyclic injection amount is the pressure duration signal P1 of the high-pressure fuel line. The time constant of P1=F(X) is expressed as τ2, which is determined by the phase between the pressure duration signal P1 of the high-pressure fuel line and the displacement X of the rack displacement sensor. The time constant τ2=t3-t2, where t2 is the starting time of the rack displacement sensor signal and t3 is the starting time of the pressure signal of the high-pressure fuel line pressure sensor.

[0027] Furthermore, in the above-mentioned method for calibrating the time constant of the diesel engine electronic speed control system, the cylinder unit transfer function is P2=F(P1), P1 is the pressure duration signal of the high-pressure oil pipe, and P2 is the gas pressure signal in the cylinder. After the pressure duration signal P1 of the high-pressure oil pipe changes, the amount of circulating fuel injection into the cylinder changes, and the gas pressure P2 in the cylinder is changed through combustion heat release; the time constant of P2=F(P1) is expressed as τ3, which is determined by the phase of the gas pressure signal P2 in the cylinder and the pressure duration signal P1 of the high-pressure oil pipe. The time constant τ3=t4-t3, t3 is the starting time of the pressure signal of the high-pressure oil pipe pressure sensor, and t4 is the starting time of the amplitude change of the pressure signal of the cylinder gas pressure sensor.

[0028] Furthermore, in the above-mentioned method for calibrating the time constant of the diesel engine electronic speed control system, the time constant τ of the diesel engine electronic speed control system is τ=τ1+τ2+τ3.

[0029] The beneficial effects of the present invention are as follows: the system and method for calibrating the time constant of the diesel engine electronic speed control system provided by the present invention can quickly obtain the time constant of the speed control system when adjusting the PID control parameters of diesel engines of different models and different powers, without relying on the structural parameter data of the diesel engine, providing an effective technical means for on-site adjustment of the PID control parameters of the diesel engine speed control system, shortening the parameter adjustment time, improving the robustness of the PID control parameters, and providing equipment and technical guarantees for the stable operation of the diesel engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a time constant calibration system of a speed control system based on synchronous testing of drive current and cylinder pressure of the present invention;

[0031] Figure 2 This is a logic diagram of a time constant calibration method for a speed control system based on synchronous testing of drive current and cylinder pressure;

[0032] Figure 3 This is a signal phase diagram of the speed control system time constant calibration method based on the synchronous test of drive current and cylinder pressure. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] The present invention provides a system for calibrating the time constant of a diesel engine electronic speed control system, comprising:

[0035] The driving current sensor is connected to the driving unit output of the electronic speed regulator controller to obtain real-time data of the driving current;

[0036] The rack displacement sensor is connected to the diesel engine oil pump rack to obtain real-time data on rack displacement;

[0037] The cylinder gas pressure sensor is connected to the combustion chamber of the diesel engine cylinder to collect the gas pressure changes in the cylinder and obtain the dynamometer data for single-cylinder power calculation;

[0038] High-pressure fuel pipe pressure sensor, connected to the high-pressure fuel pipe to obtain real-time data of fuel pressure;

[0039] The driving current sensor, rack displacement sensor, cylinder gas pressure sensor, and high-pressure oil pipe pressure sensor are respectively connected to a synchronous data acquisition unit. The synchronous data acquisition unit synchronously collects input signal data of each sensor in time, and determines the transfer function and time constant of the electronic speed control system by analyzing the phase difference of each signal data.

[0040] The specific structure of the time constant calibration system is as follows: Figure 1 As shown, the drive cable of the electronic speed governor controller 1 is connected to the drive coil of the electronic speed governor actuator 4. The drive current sensor 2 is connected in series to the output circuit of the drive cable of the electronic speed governor controller 1. The rack displacement sensor 3 is connected to the free end of the drive shaft of the electronic speed governor actuator 4. The output end of the drive shaft of the electronic speed governor actuator 4 is connected to the oil supply rack of the high-pressure oil pump 5. The high-pressure oil pump 5 is connected to the injector 8 via a high-pressure oil pipe 13. The high-pressure oil pipe pressure sensor 7 is connected to the high-pressure oil pipe 13 via a flange. The pressure node of the cylinder gas pressure sensor 9 is in direct contact with the gas in the cylinder. The diesel engine piston 12 is connected to the diesel engine load 11 via a connecting rod 6. The drive current sensor 2, rack displacement sensor 3, high-pressure oil pipe pressure sensor 7, and cylinder gas pressure sensor 9 are connected to a synchronous data acquisition unit 10.

[0041] Specifically, the driving current sensor 2 is connected in series to the driving cable loop controlled by the electronic speed regulator.

[0042] The rack displacement sensor 3 is rigidly connected to the free end of the drive shaft of the actuator 4 , and the drive end of the drive shaft is rigidly connected to the rack of the high-pressure oil pump 5 .

[0043] The high-pressure oil pipe pressure sensor 7 is connected to the high-pressure oil pipe 13 through a clamping flange, and the connection position is close to the injector 8.

[0044] The cylinder gas pressure sensor 9 is connected to the diesel engine combustion chamber through threads, and the sensitive element of the pressure sensor is in direct contact with the gas in the cylinder.

[0045] The driving current sensor 2, rack displacement sensor 3, high-pressure oil pipe pressure sensor 7, and cylinder gas pressure sensor 9 are connected to a synchronous data acquisition unit 10, which synchronously acquires input signals of each sensor in time.

[0046] Based on the above system structure, the present invention provides a time constant calibration method for a speed control system based on synchronous testing of drive current and cylinder pressure, comprising:

[0047] The synchronous acquisition unit 10 acquires the driving current signal of the driving current sensor 2 and records the value of the current signal in real time as the input of the system transfer function;

[0048] The synchronous acquisition unit 10 acquires the position voltage signal of the rack displacement sensor 3 and records the value of the voltage signal in real time as the output of the actuator transfer function link;

[0049] The synchronous acquisition unit 10 acquires the voltage signal of the high-pressure oil pipe pressure sensor 7 and records the value of the voltage signal in real time as the output of the fuel system transfer function link;

[0050] The synchronous acquisition unit 10 acquires the voltage signal of the cylinder gas pressure sensor 9 and records the value of the voltage signal in real time as the output of the cylinder unit transfer function link.

[0051] The time constant calibration method of the speed control system based on the synchronous test of driving current and cylinder pressure is as follows: Figure 2 The logic shown determines the input and output of each transfer function:

[0052] The data of the driving current sensor 2 is used as the reference input signal for time constant calibration and directly input as a function of the actuator transfer function;

[0053] The position voltage signal data of the rack displacement sensor 3 is used as the function output of the actuator transfer function and as the direct input of the high-pressure oil pump transfer function;

[0054] The voltage signal of the high-pressure oil pipe pressure sensor 7 is used as the function output of the high-pressure oil pump transfer function and as the direct input of the cylinder unit transfer function;

[0055] The voltage signal of the cylinder gas pressure sensor 9 is output as a function of the cylinder unit transfer function.

[0056] The logical relationship and time calibration criteria of the actuator transfer function, high pressure oil pump transfer function and cylinder unit transfer function are as follows: Figure 3 The actuator transfer function, high-pressure oil pump transfer function, and cylinder unit transfer function can be constructed based on models in current textbooks or references, combined with the specific structural parameters of the actuator, high-pressure oil pump, and cylinder unit. The specific function establishment methods are well known in the art.

[0057] The actuator transfer function is X = F (I), X is the rack displacement of the high-pressure oil pump, I is the drive current of the electronic speed controller, after the drive current I changes, the inductance of the actuator drive coil changes, generating electromagnetic force to drive the position of the high-pressure oil pump rack to change. This part of the response characteristic is described by the actuator transfer function as X = F (I), and the time constant of X = F (I) is expressed as τ1, which is determined by the phase of the signal I of the drive current sensor and the displacement X of the rack displacement sensor. The time constant τ1 = t2-t1. Figure 3 As shown, t1 is the starting time of the driving current sensor signal, and t2 is the starting time of the rack displacement sensor signal.

[0058] The high-pressure oil pump transfer function is P1 = F (X), where X is the rack displacement of the high-pressure oil pump and P1 is the high-pressure oil pipe sensor signal. After the rack displacement X of the high-pressure oil pump changes, the cyclic injection amount is controlled by changing the profile of the high-pressure oil pump plunger coupling. The characteristic parameter of the cyclic injection amount is the pressure duration signal P1 of the high-pressure oil pipe. This part of the response characteristic is described by the high-pressure oil pump transfer function P1 = F (X). The time constant of P1 = F (X) is expressed as τ2, which is determined by the phase between the pressure duration signal P1 of the high-pressure oil pipe and the displacement X of the rack displacement sensor. The time constant τ2 = t3-t2. Figure 3 As shown, t3 is the starting time of the pressure signal of the high-pressure oil pipe sensor.

[0059] The cylinder unit transfer function is P2 = F (P1), P1 is the pressure duration signal of the high-pressure oil pipe, and P2 is the gas pressure signal in the cylinder. After the pressure duration signal P1 of the high-pressure oil pipe changes, the amount of circulating fuel injected into the cylinder changes, and the gas pressure P2 in the cylinder is changed by combustion heat release. This part of the response characteristic is described by the cylinder unit transfer function P2 = F (P1). The time constant of P2 = F (P1) is expressed as τ3, which is determined by the phase of the gas pressure signal P2 in the cylinder and the pressure duration signal P1 of the high-pressure oil pipe. The time constant τ3 = t4-t3. Figure 3 As shown, t4 is the starting time when the amplitude of the pressure signal of the gas pressure sensor in the cylinder changes.

[0060] The time constant calibration system of the speed control system based on the synchronous test of the driving current and the cylinder pressure is the sum of the time constants of the above three transfer functions. The total time constant τ=τ1+τ2+τ3.

[0061] The method of the present invention can determine the transfer function of the controlled object required for diesel engine control parameter tuning by synchronously collecting drive current, rack displacement, and in-cylinder transient pressure data in the absence of diesel engine structural parameters, performance parameters, moment of inertia, and dynamic parameters. This can effectively solve the engineering problem of the difficulty in establishing the characteristic transfer function of diesel engine dynamics. The method for obtaining calibration data is feasible, and the calibration logic and accuracy do not depend on the structural parameters of the system. It has good versatility and can provide a theoretical basis and data support for the PID parameter tuning of diesel engine speed control. It can shorten the parameter tuning time, increase the system control margin, and improve the speed regulation accuracy. As an analysis tool and calibration method for speed control system control parameter tuning, it has good engineering application value.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0063] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A time constant calibration system for a diesel engine electronic speed control system, characterized in that: include: The driving current sensor is connected to the driving unit output of the electronic speed regulator controller to obtain real-time data of the driving current; The rack displacement sensor is connected to the diesel engine oil pump rack to obtain real-time data on rack displacement; The cylinder gas pressure sensor is connected to the combustion chamber of the diesel engine cylinder to collect the gas pressure changes in the cylinder and obtain the dynamometer data for single-cylinder power calculation; High-pressure fuel pipe pressure sensor, connected to the high-pressure fuel pipe to obtain real-time data of fuel pressure; The driving current sensor, rack displacement sensor, cylinder gas pressure sensor, and high-pressure oil pipe pressure sensor are respectively connected to a synchronous data acquisition unit, which synchronously collects input signal data of each sensor in time; According to the signal data of the driving current sensor and the signal data of the rack displacement sensor, the phase lag of the rack displacement relative to the driving current is determined, and the actuator transfer function is calibrated. The signal data of the driving current sensor is used as the time constant calibration reference input signal, as the direct input of the actuator transfer function, and the signal data of the rack displacement sensor is used as the function output of the actuator transfer function; according to the signal data of the rack displacement sensor and the signal data of the high-pressure oil pipe pressure sensor, the phase lag of the high-pressure oil pipe pressure relative to the rack displacement is determined, and the high-pressure oil pump transfer function is calibrated. The signal data of the rack displacement sensor is used as the high-pressure oil pump transfer function. The signal data of the high-pressure oil pipe pressure sensor is used as the direct input of the function, and the signal data of the cylinder gas pressure sensor is used as the function output of the high-pressure oil pump transfer function; based on the signal data of the high-pressure oil pipe pressure sensor and the signal data of the cylinder gas pressure sensor, the phase lag of the single-cylinder power change relative to the high-pressure oil pipe pressure is determined, and the cylinder unit transfer function is calibrated, the signal data of the high-pressure oil pipe pressure sensor is used as the direct input of the cylinder unit transfer function, and the signal data of the cylinder gas pressure sensor is used as the function output of the cylinder unit transfer function; by analyzing the phase difference of each signal data, the transfer function and time constant τ=τ1+τ2+τ3 of the electronic speed control system are determined, Among them, τ1 is the time constant of the actuator transfer function, τ2 is the time constant of the high-pressure oil pump transfer function, and τ3 is the time constant of the cylinder unit transfer function.

2. The diesel engine electronic speed control system time constant calibration system according to claim 1, characterized in that: The driving cable of the electronic speed regulator controller is connected to the driving coil of the electronic speed regulator actuator, and the driving current sensor is connected in series in the output loop of the driving cable of the electronic speed regulator controller.

3. The diesel engine electronic speed control system time constant calibration system according to claim 1, characterized in that: The rack displacement sensor is rigidly connected to the free end of the drive shaft of the electronic speed governor actuator, and the drive end of the drive shaft is rigidly connected to the rack of the diesel engine oil pump.

4. The diesel engine electronic speed control system time constant calibration system according to claim 1, characterized in that: The high-pressure oil pipe pressure sensor is connected to the high-pressure oil pipe through a clamping flange, and the connection position is close to the injector.

5. The diesel engine electronic speed control system time constant calibration system according to claim 1, characterized in that: The cylinder gas pressure sensor is connected to the combustion chamber of the diesel engine cylinder through a thread, and the sensitive element of the cylinder gas pressure sensor is in direct contact with the gas in the cylinder.

6. A calibration method using the diesel engine electronic speed control system time constant calibration system according to any one of claims 1 to 5, characterized in that: include: (1) The synchronous data acquisition unit synchronously collects real-time signal data of the driving current sensor, rack displacement sensor, cylinder gas pressure sensor, and high-pressure oil pipe pressure sensor; (2) determining the phase lag of the rack displacement relative to the drive current based on the signal data of the drive current sensor and the signal data of the rack displacement sensor, and calibrating the actuator transfer function, wherein the signal data of the drive current sensor is used as a time constant calibration reference input signal and as a direct input of the actuator transfer function, and the signal data of the rack displacement sensor is used as a function output of the actuator transfer function; (3) Based on the signal data of the rack displacement sensor and the signal data of the high-pressure oil pipe pressure sensor, the phase lag of the high-pressure oil pipe pressure relative to the rack displacement is determined, and the high-pressure oil pump transfer function is calibrated, wherein the signal data of the rack displacement sensor is used as the direct input of the high-pressure oil pump transfer function, and the signal data of the high-pressure oil pipe pressure sensor is used as the function output of the high-pressure oil pump transfer function; based on the signal data of the high-pressure oil pipe pressure sensor and the signal data of the cylinder gas pressure sensor, the phase lag of the single-cylinder power change relative to the high-pressure oil pipe pressure is determined, and the cylinder unit transfer function is calibrated, wherein the signal data of the high-pressure oil pipe pressure sensor is used as the direct input of the cylinder unit transfer function, and the signal data of the cylinder gas pressure sensor is used as the function output of the cylinder unit transfer function; (4) Using the transfer function calibrated in steps (2) and (3), determine the time constant τ = τ1 + τ2 + τ3 of the diesel engine electronic speed control system. Among them, τ1 is the time constant of the actuator transfer function, τ2 is the time constant of the high-pressure oil pump transfer function, and τ3 is the time constant of the cylinder unit transfer function.

7. The method for calibrating the time constant of the diesel engine electronic speed control system according to claim 6, characterized in that: The actuator transfer function is in the form of X=F(I), where X is the rack displacement of the high-pressure oil pump and I is the drive current of the electronic speed regulator controller. When the drive current I changes, the inductance of the actuator drive coil changes, generating an electromagnetic force to drive the position of the high-pressure oil pump rack to change. The time constant of X=F(I) is expressed as τ1, which is determined by the phase between the signal I of the drive current sensor and the displacement X of the rack displacement sensor. The time constant τ1=t2-t1, t1 is the starting time of the drive current sensor signal, and t2 is the starting time of the rack displacement sensor signal.

8. The method for calibrating the time constant of the diesel engine electronic speed control system according to claim 7, characterized in that: The high-pressure oil pump transfer function is P1=F(X), where X is the rack displacement of the high-pressure oil pump and P1 is the signal from the high-pressure oil line pressure sensor. When the rack displacement X of the high-pressure oil pump changes, the cyclic injection amount is controlled by changing the profile of the high-pressure oil pump plunger coupling. The characteristic parameter of the cyclic injection amount is the pressure duration signal P1 of the high-pressure oil line. The time constant of P1=F(X) is represented by τ2, which is determined by the phase between the pressure duration signal P1 of the high-pressure oil line and the displacement X of the rack displacement sensor. The time constant τ2=t3-t2, where t2 is the starting time of the rack displacement sensor signal and t3 is the starting time of the pressure signal of the high-pressure oil line pressure sensor.

9. The method for calibrating the time constant of the diesel engine electronic speed control system according to claim 8, characterized in that: The cylinder unit transfer function is P2=F(P1), where P1 is the pressure duration signal of the high-pressure oil pipe, and P2 is the gas pressure signal in the cylinder. When the pressure duration signal P1 of the high-pressure oil pipe changes, the amount of circulating fuel injected into the cylinder changes, and the gas pressure P2 in the cylinder is changed through combustion heat release. The time constant of P2=F(P1) is expressed as τ3, which is determined by the phase between the gas pressure signal P2 in the cylinder and the pressure duration signal P1 of the high-pressure oil pipe. The time constant τ3=t4-t3, where t3 is the starting time of the pressure signal of the high-pressure oil pipe pressure sensor, and t4 is the starting time of the amplitude change of the pressure signal of the cylinder gas pressure sensor.

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