Method for obtaining injection time of fuel injector

Abstract

The present application relates to a kind of the present application fuel injector injection time obtaining method, using the displacement signal detection of needle valve is combined with the driving current waveform of fuel injector, obtains the opening time of fuel injector and the closing time of fuel injector in the simplified formula of fuel injector injection time, using experimental method obtains the time correction factor in formula to correct the opening time of fuel injector and the closing time of fuel injector, again superimposed fuel injector injection obtains fuel injector injection time, the fuel injector injection time obtained by the method of the present application replaces the fuel injector injection time directly estimated according to the opening degree position of traditional fuel injector, more close to the real value of data. Obtain more accurate fuel injector injection time, so that speed control is more stable, improve economic control fuel.

Description

Technical Field

[0001] This invention relates to the field of fuel control technology for engines, and particularly to a method for obtaining injector injection time. Background Technology

[0002] In the engine's fuel control system, to enable the engine's electronic control system to achieve precise control of the fuel injection quantity, thereby meeting the engine's torque requirements and optimizing carbon emissions, ordinary electronic control systems use coarse calibration to handle the injection time when the injector is partially open. However, this time is not to be underestimated, especially in modern high-pressure injection systems.

[0003] Currently, a rough calibration method determines the injection quantity by measuring the peak-hold drive time of the injector. However, this continuous process is not linear. Because of the existence of a partially open state, the electronic control system collects the feedback voltage of the injector's opening position and calculates the injection quantity in the partially open state based on the injector's opening position. If this is inaccurate, it will affect the speed regulation and waste fuel. Figure 1 This is an injection rate diagram obtained from laboratory tests. t1 is the onset point (calculated from the rise time), t2 is the fully open point, t3 is the beginning of the closing point (calculated from the fall time), and t4 is the fully closed point. Based on current methods of obtaining injector injection times, t2 and t4 are not readily available; they are obtained using… Figure 1 The injection time, TI_Hyd, is obtained through calibration. However, as the injectors age, the calculations for points t1 and t3 become increasingly inaccurate. Consequently, the discrepancy between the actual injected fuel quantity and the set injection quantity grows larger and larger. Summary of the Invention

[0004] To address the inaccuracy of current methods in obtaining injector injection time, a new method for obtaining injector injection time is proposed. This method estimates the opening and closing time of the injector by using the injector drive current waveform and the voltage signal at the injector needle valve position, which is closer to the true value of the data than traditional methods.

[0005] The technical solution of the present invention is: a method for obtaining the injection time of an injector, wherein the injection time of the injector Ti_Corr = T_open*k1 + Tk + T_close*k2, where T_open is the injector opening time; Tk is the injector injection time; T_close is the injector closing time; and k1 and k2 are opening and closing time correction factors.

[0006] T_open and T_close are obtained by detecting the displacement signal of the injector needle valve and combining it with the driving current waveform of the injector. k1 and k2 are obtained by the injector experimental test method.

[0007] Furthermore, the methods for obtaining k1 and k2 are as follows: On an oil pump test bench at a normal temperature of 25 degrees Celsius, using standard diesel fuel and a fuel pressure of 5 bar, various injectors are tested to obtain the corresponding time correction factor for each injector. The specific steps are as follows:

[0008] 1) When the displacement sensor indicates that it is fully open, use the oil pump to measure the amount of oil consumed, Q1;

[0009] 2) After the injector is fully open, it sprays at full flow. Before the injector is closed, the amount of fuel consumed, Q2, is measured using the fuel pump. Then, k1 = Q1 / Q2.

[0010] 3) The injector begins to close until the displacement sensor indicates that it is completely closed. The amount of fuel consumed, Q3, is measured using the pump oil. Then, k2 = Q3 / Q2.

[0011] Furthermore, the injector opening time is as follows: the timer starts when the injector opening signal is issued and ends when the displacement feedback voltage signal of the needle valve reaches 0 and the current value in the drive current waveform enters the stable fluctuation of the fully open injector current. This period is the injector opening time.

[0012] Furthermore, the injector closing time is as follows: timing begins when the injector closing signal is issued. When the displacement feedback voltage signal of the needle valve reaches a negative pole, the negative voltage jump point during the process of the feedback voltage of the injector opening position rebounding towards 0 is the injector fully closing time point. At this time, the timing ends, and this period is the injector closing time.

[0013] An application of a method for obtaining injector injection time, used to estimate injector injection time in a high-pressure injection system.

[0014] The beneficial effects of the present invention are as follows: the method for obtaining the injector injection time of the present invention obtains a more accurate injector injection time, which makes the speed control more stable and improves fuel economy. Attached Figure Description

[0015] Figure 1 A graph showing the jet rate obtained from laboratory tests;

[0016] Figure 2 This is a signal diagram showing the operation of the fuel injector of the present invention;

[0017] Figure 3 This is a diagram showing the actual measured injection oil volume of the present invention. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0019] Figure 2 This is a signal diagram showing the operation of the injector in this invention. Ti represents the power-on time; T_open represents the time from initial power-on to full opening of the injector; T_close represents the time from initial power-off to full closing of the injector; T1 represents the dead time when the injector starts to power on, with the injector opening at 0; T2 represents the time when the injector opening gradually increases to full opening; Qs represents the injection quantity per unit time (ml); T3 represents the time from the start of decreasing injector flow to complete closure; T4 represents the time from power-off of the injector to the complete dispensing of fuel; and Ti_hyd represents the total time for the injector to dispense fuel.

[0020] The present invention discloses a method for obtaining injector injection time. This method utilizes needle valve displacement signal detection combined with the injector's drive current waveform to obtain the injector opening and closing times in a simplified injector injection time formula. An experimental method is then used to obtain a time correction factor in the formula to correct the injector opening and closing times. Finally, the injector injection times are superimposed to obtain the final injector injection time. In this injector injection time algorithm, the injector injects at full flow throughout the injection process. The resulting injector injection time, instead of the traditional method of directly estimating the injector injection time based on its opening position, more closely approximates the true value of the data.

[0021] The green line represents the peak-hold (constant maximum value) current waveform driven by the fuel injector. It is clear that the current spike is high and steep in order to quickly release the fuel supply. This is the operating current waveform provided by the fuel injector manufacturer.

[0022] The blue line represents the voltage signal converted from the needle valve's displacement signal. Timing begins when the injector-opening signal is issued and ends when the blue line voltage reaches 0 and the green line current value smoothly transitions from its peak to the fully open injector current. This period is considered the injector-opening time. Timing begins when the injector-closing signal is issued. At this point, the blue voltage signal shows a negative pole. Timing continues until the feedback voltage of the collected injector opening position reaches the corresponding closing voltage. Figure 2 The negative voltage jump point in the signal can be considered as the injector being completely closed and the injection quantity being 0. This period is called T_close.

[0023] The injection rate of the injector is measured on an oil pump measuring station to calculate the upper-level correction factors for the opening and closing phases. To simplify the calculation, this correction algorithm assumes that the injector injects at full flow throughout the injection process. However, the injection time during the opening phase and the injection time during the closing phase are calibrated using a correction factor.

[0024] Traditional control methods will use Figure 1 The TI_Hyd is used as a rough injection time. However, since this invention uses the displacement feedback signal of the needle valve, the start time and closing time of the injector can be measured. Therefore, the injector injection time Ti_Corr = T_open (injector opening time) * k1 + Tk (injector injection time) + T_close (injector closing time) * k2, where k1 is the injector opening time correction factor; k2 is the injector closing time correction factor; the time correction factors k1 and k2 were obtained through previous experiments.

[0025] The methods for obtaining k1 and k2 are as follows: On a fuel pump test bench at a normal temperature of 25 degrees Celsius, using standard diesel fuel and a fuel pressure of 5 bar, various fuel injectors are tested to obtain the corresponding time correction factors for each injector. The specific steps are as follows:

[0026] Step 1: When the displacement sensor indicates that it is fully open, use the oil pump to measure the amount of oil consumed, Q1;

[0027] Step 2: After the injector is fully open, inject at full flow. Before the injector closes, use the fuel pump to measure the amount of fuel consumed, Q2. Then, k1 = Q1 / Q2

[0028] Step 3: The injector begins to close until the displacement sensor indicates that it is completely closed. Use the pump to measure the amount of fuel consumed, Q3, then k2 = Q3 / Q2.

[0029] Figure 3 The measured fuel injection volume diagram of this invention is consistent with the fuel injector injection time obtained by using the method of this invention, proving that the simplified fuel injector injection time formula of this invention is feasible.

[0030] The embodiments described above merely illustrate specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for obtaining the injection time of a fuel injector, characterized in that, The injector injection time Ti_Corr=T_open k1+Tk+T_close k2, where T_open is the injector opening time; Tk is the injector full-flow injection time; T_close is the injector closing time; k1 and k2 are the opening and closing time correction factors; The method for obtaining T_open is as follows: the timer starts when the injector is opened and ends when the displacement feedback voltage signal of the needle valve reaches 0 and the current value in the drive current waveform enters the stable fluctuation of the fully opened injector current. This period of time is the injector opening time. The method for obtaining T_close is as follows: when a signal to close the injector is sent to start timing, the displacement feedback voltage signal of the needle valve shows a negative pole, and the negative voltage jump point in the process of the feedback voltage of the injector opening position rebounding towards 0 is the time point when the injector is completely closed. At this time, the timing ends, and this period of time is the injector closing time. The method for obtaining k1 and k2 is as follows: The injector is tested on an oil pump test bench at a normal temperature of 25 degrees Celsius, using standard diesel fuel at a fuel pressure of 5 bar. The specific steps are as follows: 1) When the displacement sensor indicates that it is fully open, use the oil pump to measure the amount of oil consumed, Q1; 2) After the injector is fully open, it sprays at full flow. Before the injector is closed, the amount of fuel consumed, Q2, is measured using the fuel pump. Then, k1 = Q1 / Q2. 3) The injector begins to close until the displacement sensor indicates that it is completely closed. The amount of fuel consumed, Q3, is measured using the fuel pump. Then, k2 = Q3 / Q2.

2. The method for obtaining the injection time of an injector as described in claim 1, characterized in that, Estimate the injector injection time in a high-pressure injection system.

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