Engine closed-loop control method, system and medium for identifying jet duration

Abstract

The present invention discloses an engine closed-loop control method, system and medium for identifying the duration of injection, which relates to the field of engine closed-loop control. The method comprises: obtaining a pressure signal in a high-pressure gas pipe of a fuel injector, and determining the injection opening time and injection ending time of the fuel injector based on the pressure signal; determining the injection duration based on the injection opening time and the injection ending time; inputting the pressure signal and the injection duration into a neural network model to obtain injection amount prediction data; applying a fuzzy PID control algorithm based on the injection amount prediction data and a target injection amount to obtain an injection pulse width signal that meets the target injection amount; and controlling the fuel injector to perform injection operation based on the injection pulse width signal. Compared with the traditional open-loop control method, the present invention can realize online feedback of the injection amount, and the injection amount control is more accurate.

Description

Technical Field

[0001] The invention relates to the field of engine closed-loop control, and in particular to a closed-loop control method, system and medium for a high-pressure direct injection engine capable of online identifying the injection duration. Background Art

[0002] High-pressure direct injection (HPDI) is one of the most important technologies in modern natural gas engines. Its working principle is to inject a small amount of diesel fuel into the cylinder in the late compression stroke to ignite the high-pressure natural gas injected into the cylinder, forming a coexistence of premixed combustion and diffusion combustion, with diffusion combustion as the dominant mode. The combustion mode in the cylinder of the HPDI natural gas engine is dominated by diffusion combustion, which can further improve power and thermal efficiency.

[0003] At present, the most advanced dual-fuel injection system uses dual-fuel injectors. This structure can realize the coaxial staggered injection of diesel and natural gas, and can ensure the stability of the contact area between natural gas and diesel flames and the combustion work. The dual fuels are injected into the cylinder successively through the injector. The injection process involves multiple injection parameters such as injection pressure, injection timing, dual fuel injection interval, and pilot diesel injection amount and main fuel natural gas injection amount. The researchers analyzed the mechanism of the influence of pilot diesel on the natural gas injection characteristics. The injection characteristics will be significantly affected by the pressure fluctuations caused by the injection of pilot diesel. This influence is affected by the multi-physical fields of hydraulic pneumatic-electromagnetic and is difficult to determine through engine calibration or empirical formulas. This influence will make it difficult to achieve precise control of the open-loop control strategy of the engine based on offline testing to obtain the injection volume MAP, and the open-loop control strategy cannot adapt to changes in complex environments. Summary of the invention

[0004] The purpose of the present invention is to provide an engine closed-loop control method, system and medium for identifying the injection duration, which solves the problem of inaccuracy of the injection amount open-loop control method based on MAP calibration.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] An engine closed-loop control method for identifying jet duration, the method comprising:

[0007] Acquire a pressure signal in a high-pressure gas pipe of a fuel injector, and determine an injection start time and an injection end time of the fuel injector based on the pressure signal;

[0008] Determining the jet duration based on the jet start time and the jet end time;

[0009] Inputting the pressure signal and the jet duration into a neural network model to obtain jet volume prediction data;

[0010] Applying a fuzzy PID control algorithm based on the jet volume prediction data and the target jet volume to obtain a jet pulse width signal that meets the target jet volume;

[0011] The fuel injector is controlled to perform an injection operation based on the injection pulse width signal.

[0012] Optionally, determining the injection start time and injection end time of the fuel injector based on the pressure signal specifically includes:

[0013] Using fast Fourier transform to perform time-frequency analysis on the pressure signal segment by segment, the frequency variation of the non-stationary signal in different time intervals is obtained;

[0014] Determine the energy density spectrum of the signal based on the frequency change;

[0015] determining a signal energy based on an energy density spectrum of the signal;

[0016] Calculating a transient average frequency based on the signal energy;

[0017] The jet start time and the jet end time are determined based on the transient average frequency.

[0018] Optionally, applying a fuzzy PID control algorithm based on the jet volume prediction data and the target jet volume to obtain a jet pulse width signal that meets the target jet volume specifically includes:

[0019] determining a jet volume difference according to the jet volume prediction data and the target jet volume;

[0020] The jet amount difference is input into the fuzzy controller to obtain the proportional coefficient increment, integral coefficient increment and differential coefficient increment of the PID controller;

[0021] Calculate the proportional coefficient, integral coefficient and differential coefficient of the PID controller according to the proportional coefficient increment, the integral coefficient increment and the differential coefficient increment;

[0022] The PID controller is controlled to output the jet pulse width signal according to the proportional coefficient, the integral coefficient and the differential coefficient.

[0023] The present invention also provides an engine closed-loop control system for identifying the jet duration, the system comprising:

[0024] A data acquisition module, used to acquire a pressure signal in a high-pressure gas pipe of a fuel injector, and determine an injection start time and an injection end time of the fuel injector based on the pressure signal;

[0025] An injection duration calculation module, used for determining the injection duration based on the injection start time and the injection end time;

[0026] An injection volume prediction module, used for inputting the pressure signal and the injection duration into a neural network model to obtain injection volume prediction data;

[0027] An air jet pulse width output module, used for applying a fuzzy PID control algorithm based on the air jet amount prediction data and the target air jet amount to obtain an air jet pulse width signal that satisfies the target air jet amount;

[0028] The injection control module is used for controlling the fuel injector to perform an injection operation based on the injection pulse width signal.

[0029] Optionally, the data acquisition module specifically includes:

[0030] A Fourier transform unit, used for performing time-frequency analysis of the pressure signal segment by segment using a fast Fourier transform to obtain frequency changes of the non-stationary signal in different time intervals;

[0031] A dimensionality reduction processing unit, used to determine the energy density spectrum of the signal based on the frequency change; determine the signal energy based on the energy density spectrum of the signal; and calculate the transient average frequency based on the signal energy;

[0032] A time calculation unit is used to determine the jet start time and the jet end time based on the transient average frequency.

[0033] Optionally, the jet pulse width output module specifically includes:

[0034] a difference calculation unit, configured to determine a jet volume difference according to the jet volume prediction data and the target jet volume;

[0035] A fuzzy control unit, used for inputting the jet amount difference into a fuzzy controller to obtain a proportional coefficient increment, an integral coefficient increment and a differential coefficient increment of a PID controller;

[0036] A PID coefficient calculation unit, used for calculating the proportional coefficient, the integral coefficient and the differential coefficient of the PID controller according to the proportional coefficient increment, the integral coefficient increment and the differential coefficient increment;

[0037] The jet pulse width output unit is used to control the PID controller to output the jet pulse width signal according to the proportional coefficient, the integral coefficient and the differential coefficient.

[0038] The present invention also provides a computer-readable storage medium storing a computer program, which implements the engine closed-loop control method for identifying the jet duration when the computer program is executed by a processor.

[0039] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0040] The present invention provides a closed-loop control method, system and medium for a high-pressure direct injection engine for online identification of jet duration. By online identification of the jet duration, a jet duration and jet quantity prediction model is established, and online prediction feedback of the engine jet quantity is realized. Based on the online feedback of the jet quantity prediction data, the jet quantity closed-loop control is applied, and the influence of the injection process on the subsequent jet quantity can be identified, thereby achieving the purpose of accurate and reliable control of the engine jet quantity. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 A flow chart of an engine closed-loop control method for identifying jet duration provided in Example 1 of the present invention;

[0043] Figure 2 A schematic diagram of online identification of jet duration provided by an embodiment of the present invention;

[0044] Figure 3 The neural network prediction model structure provided in Example 1 of the present invention;

[0045] Figure 4 This is a closed-loop control flow chart of the fuzzy PID control algorithm provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The purpose of the present invention is to provide an engine closed-loop control method, system and medium for identifying the injection duration, which solves the problem of inaccuracy of the injection amount open-loop control method based on MAP calibration.

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] like Figure 1 As shown, this embodiment provides an engine closed-loop control method for identifying the injection duration, the method comprising:

[0051] S1: Obtaining a pressure signal in a high-pressure gas pipe of a fuel injector, and determining an injection start time and an injection end time of the fuel injector based on the pressure signal.

[0052] Wherein, step S1 specifically includes:

[0053] (1) The pressure signal is subjected to time-frequency analysis segment by segment using fast Fourier transform to obtain the frequency variation of the non-stationary signal in different time intervals.

[0054] (2) Determine the energy density spectrum of the signal based on the frequency change.

[0055] (3) Determine the signal energy based on the energy density spectrum of the signal.

[0056] (4) Calculate the transient average frequency based on the signal energy.

[0057] (5) The jet start timing and the jet end timing are determined based on the transient average frequency.

[0058] More specifically, online identification of jet duration:

[0059] The gas pressure signal at the high-pressure gas pipe is used as the online feedback signal, and the time domain characteristics of the signal are highlighted by the time-frequency analysis method;

[0060] The frequency variation of the non-stationary signal in different time intervals is obtained by performing time-frequency analysis on the signal segment by segment through fast Fourier transform, which is defined as:

[0061]

[0062] Where dP(t) is the differential signal of gas pressure; h(t-τ) is the window function (Hanning is selected in this paper); τ is the center of the window function.

[0063] The energy density spectrum of the signal is defined as follows:

[0064] e(f,τ)=[STFT(τ,f)] 2 2)

[0065] The signal energy is defined as follows:

[0066]

[0067] In order to reduce the calculation process of the engine ECU and realize the real-time acquisition of the jet duration, the transient average frequency (MIF) is used as the identification signal. MIF is the transient average frequency obtained by frequency weighting, which can retain the signal time domain resolution and is defined as follows:

[0068]

[0069] S2: Determine the jet duration based on the jet start time and the jet end time.

[0070] The gas pressure signal is transformed by fast Fourier transform, and then the transient average frequency obtained by frequency weighting can realize the identification of the start of injection (SOI) and the end of injection (EOI). Figure 2 As shown, the injection duration (IDT) is calculated as:

[0071] IDT=EOI-SOI 5)

[0072] S3: Input the pressure signal and the jet duration into a neural network model to obtain jet volume prediction data.

[0073] Jet volume model establishment:

[0074] The radial basis function neural network is selected as the jet flow prediction model, which has a simple structure, such as Figure 3 As shown, it can avoid complex calculations and has a high generalization ability. The present invention uses the jet volume as the output of the prediction model and uses two inputs (jet pressure and IDT)

[0075] The Gaussian kernel function is the most commonly used type of radial basis function, as shown in formula (6):

[0076]

[0077] Where xc is the coordinate of the center point, x is the coordinate to be classified, and σ is the adjustable width parameter.

[0078] In the radial basis neural network, the input is:

[0079]

[0080] Among them, c j =[c j1 ,...,c jn ] is the center vector of the jth neuron in the hidden layer, and n represents the number of columns of the vector.

[0081] Network output:

[0082] y1=ω1h1+ω2h2+...+ω m hm 8)

[0083] Where ω=[ω1,...ω m ] T is the network weight

[0084] The output layer error starts from the output layer, and propagates back layer by layer. The error of each unit in the hidden layer can be indirectly calculated, and the weight of the previous layer is corrected based on this error. The output error of the network is:

[0085] e i =y l d -y l 9)

[0086] Parameter y l d Represents the training set experimental data.

[0087] The training target error indicator is:

[0088]

[0089] Correct the weights according to the gradient descent method:

[0090]

[0091] Among them, Δω is the corrected weight, η is the learning rate, E is the training error index, and e l is the input error, h j is the output of the jth neuron in the hidden layer.

[0092] In order to speed up the convergence rate, the previous weight correction is usually added to the weight correction, which is called the inertia term. When the number of iterations reaches the set maximum value or the training target error index reaches the requirement, the network training ends.

[0093] S4: Applying a fuzzy PID control algorithm based on the jet quantity prediction data and the target jet quantity to obtain a jet pulse width signal that meets the target jet quantity.

[0094] Wherein, step S4 specifically includes:

[0095] (1) An injection amount difference is determined based on the injection amount prediction data and the target injection amount.

[0096] (2) The jet volume difference is input into the fuzzy controller to obtain the proportional coefficient increment, integral coefficient increment and differential coefficient increment of the PID controller.

[0097] (3) Calculating the proportional coefficient, integral coefficient and differential coefficient of the PID controller according to the proportional coefficient increment, the integral coefficient increment and the differential coefficient increment.

[0098] (4) Control the PID controller to output the jet pulse width signal according to the proportional coefficient, the integral coefficient and the differential coefficient.

[0099] More specifically, closed-loop control of the injection volume based on online feedback:

[0100] The PID controller, as the core of the closed-loop control of the present invention, is mainly composed of a proportional link, an integral link and a differential link. It is a linear control method, and its transfer function is:

[0101]

[0102] In order to make up for the shortcomings of the linear control mode of the PID controller, the present invention adopts a fuzzy PID control algorithm. The fuzzy PID control algorithm combines the advantages of PID control and fuzzy control, performs nonlinear processing on the PID controller, and realizes the nonlinear mapping relationship between the system characteristic change and the control quantity, thereby integrating the simplicity, flexibility and robustness of PID control and fuzzy control.

[0103] The obtained jet volume prediction data is used as the input signal of the fuzzy PID algorithm, such as Figure 4 As shown in the figure, the error e(t) and de / dt are obtained by comparing the jet volume with the reference jet volume. The two are used as the input of the fuzzy controller. They are fuzzified according to the membership function. The fuzzy rule of the area center is adopted. After being clarified according to the output membership function, the fuzzy controller outputs the increments of the three PID parameters as Δk p , Δk i , Δk d .

[0104]

[0105] The final PID parameter is K p , K i , K d . K p is the proportionality coefficient, K i is the integration coefficient, K d is the differential coefficient.

[0106] In the present invention, the obtained injection amount prediction data is used as the input signal of the fuzzy PID control algorithm, and the injection pulse width ET of the injector is used as the output signal to drive the injector to inject. By identifying the injection amount of this injection, the injection pulse width of the next injection can be obtained. Due to the adjustment of the basic PID closed-loop parameters by fuzzy control, a faster and more accurate closed-loop control of the injection amount can be achieved.

[0107] S5: Controlling the fuel injector to perform injection operation based on the injection pulse width signal.

[0108] In the present invention, the obtained injection amount prediction data is used as the input signal of the fuzzy PID control algorithm, and the injection pulse width ET of the injector is used as the output signal to drive the injector to inject. By identifying the injection amount of this injection, the injection pulse width of the next injection can be obtained. Due to the adjustment of the basic PID closed-loop parameters by fuzzy control, a faster and more accurate closed-loop control of the injection amount can be achieved.

[0109] This embodiment has the following advantages:

[0110] 1) Compared with the traditional open-loop control method, the present invention can realize online feedback of the injection amount, and the injection amount control method is more accurate and can adapt to different working conditions of the engine.

[0111] 2) The injection quantity control method proposed in the present invention can avoid the influence of diesel injection on the injection quantity and cause the reduction of control accuracy, and is suitable for different fuel injection strategies of dual-fuel injectors.

[0112] 3) Compared with the existing combustion closed-loop control method, the present invention does not need to destroy the overall structure of the engine injector and the combustion chamber, and can achieve out-of-cylinder measurement. It only needs to install a pressure sensor on the high-pressure air pipe. The equipment is simple, the working environment is more soothing, the sensor has a long life and low cost.

[0113] 4) The present invention proposes a closed-loop control method for a high-pressure direct injection engine based on online identification of the injection duration, thereby realizing rapid closed-loop control of the injection amount under actual working conditions.

[0114] Example 2

[0115] This embodiment provides an engine closed-loop control system for identifying the jet duration, the system comprising:

[0116] The data acquisition module is used to acquire the pressure signal in the high-pressure gas pipe of the fuel injector, and determine the injection start time and injection end time of the fuel injector based on the pressure signal.

[0117] Wherein, the data acquisition module specifically includes:

[0118] The Fourier transform unit is used to perform time-frequency analysis on the pressure signal segment by segment using fast Fourier transform to obtain the frequency change of the non-stationary signal in different time intervals.

[0119] A dimensionality reduction processing unit is used to determine the energy density spectrum of the signal based on the frequency change; determine the signal energy based on the energy density spectrum of the signal; and calculate the transient average frequency based on the signal energy.

[0120] A time calculation unit is used to determine the jet start time and the jet end time based on the transient average frequency.

[0121] The jet duration calculation module is used to determine the jet duration based on the jet start time and the jet end time.

[0122] The jet volume prediction module is used to input the pressure signal and the jet duration into a neural network model to obtain jet volume prediction data.

[0123] The jet pulse width output module is used to apply a fuzzy PID control algorithm based on the jet quantity prediction data and the target jet quantity to obtain a jet pulse width signal that meets the target jet quantity.

[0124] Wherein, the jet pulse width output module specifically includes:

[0125] The difference calculation unit is used to determine the jet quantity difference according to the jet quantity prediction data and the target jet quantity.

[0126] The fuzzy control unit is used to input the jet volume difference into the fuzzy controller to obtain the proportional coefficient increment, integral coefficient increment and differential coefficient increment of the PID controller.

[0127] A PID coefficient calculation unit is used to calculate the proportional coefficient, integral coefficient and differential coefficient of the PID controller according to the proportional coefficient increment, the integral coefficient increment and the differential coefficient increment.

[0128] The jet pulse width output unit is used to control the PID controller to output the jet pulse width signal according to the proportional coefficient, the integral coefficient and the differential coefficient.

[0129] The injection control module is used for controlling the fuel injector to perform an injection operation based on the injection pulse width signal.

[0130] Example 3

[0131] An embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the engine closed-loop control method for identifying the jet duration of the first embodiment is implemented.

[0132] In addition, this embodiment also provides an electronic device, including a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the engine closed-loop control method for identifying the jet duration of embodiment one.

[0133] Optionally, the above-mentioned electronic device may be a server.

[0134] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented 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.

[0135] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0136] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0137] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0138] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0139] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An engine closed-loop control method for identifying jet duration, characterized in that: The method comprises: Acquire a pressure signal in a high-pressure gas pipe of a fuel injector, and determine an injection start time and an injection end time of the fuel injector based on the pressure signal; Determining the jet duration based on the jet start time and the jet end time; Inputting the pressure signal and the jet duration into a neural network model to obtain jet volume prediction data; Applying a fuzzy PID control algorithm based on the jet volume prediction data and the target jet volume to obtain a jet pulse width signal that meets the target jet volume; Controlling the fuel injector to perform an injection operation based on the injection pulse width signal; Wherein, determining the injection start time and injection end time of the fuel injector based on the pressure signal specifically includes: Using fast Fourier transform to perform time-frequency analysis on the pressure signal segment by segment, the frequency variation of the non-stationary signal in different time intervals is obtained; Determine the energy density spectrum of the signal based on the frequency change; determining a signal energy based on an energy density spectrum of the signal; Calculating a transient average frequency based on the signal energy; Determining the jet start time and the jet end time based on the transient average frequency; Wherein, applying a fuzzy PID control algorithm based on the jet volume prediction data and the target jet volume to obtain a jet pulse width signal that meets the target jet volume specifically includes: determining a jet volume difference according to the jet volume prediction data and the target jet volume; The jet amount difference is input into the fuzzy controller to obtain the proportional coefficient increment, integral coefficient increment and differential coefficient increment of the PID controller; Calculate the proportional coefficient, integral coefficient and differential coefficient of the PID controller according to the proportional coefficient increment, the integral coefficient increment and the differential coefficient increment; The PID controller is controlled to output the jet pulse width signal according to the proportional coefficient, the integral coefficient and the differential coefficient.

2. An engine closed-loop control system for identifying jet duration, characterized in that: The system comprises: A data acquisition module, used to acquire a pressure signal in a high-pressure gas pipe of a fuel injector, and determine an injection start time and an injection end time of the fuel injector based on the pressure signal; The data acquisition module specifically includes: A Fourier transform unit, used for performing time-frequency analysis of the pressure signal segment by segment using a fast Fourier transform to obtain frequency changes of the non-stationary signal in different time intervals; A dimensionality reduction processing unit, used to determine the energy density spectrum of the signal based on the frequency change; determine the signal energy based on the energy density spectrum of the signal; and calculate the transient average frequency based on the signal energy; a time calculation unit, used for determining the jet start time and the jet end time based on the transient average frequency; An injection duration calculation module, used for determining the injection duration based on the injection start time and the injection end time; An injection volume prediction module, used for inputting the pressure signal and the injection duration into a neural network model to obtain injection volume prediction data; An air jet pulse width output module, used for applying a fuzzy PID control algorithm based on the air jet amount prediction data and the target air jet amount to obtain an air jet pulse width signal that satisfies the target air jet amount; The jet pulse width output module specifically includes: a difference calculation unit, configured to determine a jet volume difference according to the jet volume prediction data and the target jet volume; A fuzzy control unit, used for inputting the jet amount difference into a fuzzy controller to obtain a proportional coefficient increment, an integral coefficient increment and a differential coefficient increment of a PID controller; A PID coefficient calculation unit, used for calculating the proportional coefficient, the integral coefficient and the differential coefficient of the PID controller according to the proportional coefficient increment, the integral coefficient increment and the differential coefficient increment; An air jet pulse width output unit, used to control the PID controller to output the air jet pulse width signal according to the proportional coefficient, the integral coefficient and the differential coefficient; The injection control module is used for controlling the fuel injector to perform an injection operation based on the injection pulse width signal.

3. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the engine closed-loop control method for identifying the injection duration described in claim 1 is implemented.

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