JPS58133472A - Fuel injection timing measuring device for diesel engine - Google Patents

Abstract

PURPOSE:To have an accurate sensing of the injection timing by changing the reference voltage level in accordance with the operating conditions, by sensing only valve lift signal generated within a certain specified range of crank angle and by removing signals from adjacent injection valves. CONSTITUTION:A lift sensor signal S1 is taken out of a sensor 7 by opening a fuel injection valve, and fed into an amplifier circuit 21 to obtain a signal S6. Besides normal signal component S61, this signal S6 contains an irregular signal component S62 to be generated owing to displacement of the needles of injection valves of adjacent cylinders. On the other hand, the angle signal S4 given by a crank angle sensor 23 is fed into an F-V converter 24 to have a convertion into variable voltage level signal S7, and then a sensing signal S8 is obtained through comparison of the amplification signal S6 with the variable voltage level signal S7 at a comparator circuit 22. The signal S7 is adjusted previously by the F-V converter so as to be always higher than the voltage level of the irregular signal component S62. Thus the irregular signal component is removed, and now the sensed signal S8 contains only normal signal components.

Description

[Detailed description of the invention] This invention relates to a timing measuring device.

As a conventional fuel injection timing measuring device for this type of cypress, there is a Japanese patent application 1974-D shown in FIG. There is one proposed by No. t441. When high-pressure fuel from a high-pressure pump is supplied to the fuel injection valve through the fuel supply passage 1, the needle valve 3 is displaced upward to open the nozzle hole and inject fuel, and the spring and The pressing force applied to the lift sensor 7 made of a piezoelectric element or the like through the ground plate 1 increases, and an electromotive force is generated in the lift sensor 7, and the electromotive force is expressed as the lift sensor signal S/ (see Fig. 2 (B)). (see solid line) as electrode 1
taken from. After slicing the sensor signal 8/to the detection level S (see the broken line in FIG. 2(B)), the waveform is shaped to obtain a shaped signal 83 (see FIG. 1(C)). This shaping signal S3 and the l-〇〇 angle signal S supplied from the engine crank angle sensor (not shown)
The lift angle position of the needle valve 3 is determined by
From the TS, a signal 87 (see @-in the figure) indicating the offset jiT/ at the engine reference angle value 1lITFI is obtained. This detection No. 411 S! Controls the fuel injection timing, etc. of the auxiliary fuel injector, further calculates the fuel injection amount from this measurement information and injection period, determines the difference from the target fuel injection amount, and performs corrective control to correct the difference. By doing so, we aim to reduce fuel consumption and harmful gas emissions.

However, in such a fuel injection timing measurement device, when a seven-point sensor is attached to seven out of five cylinders, the movement of the needle valve of the fuel injection valve of the cylinder adjacent to the cylinder in which it is attached is detected. An impact force corresponding to the above propagates to the lift sensor 7, and the lift sensor 7 detects this impact force as a signal component SO. The abnormal signal component 8θ is similar to the normal signal component 80, which indicates the displacement of the needle valve J of the tPX fuel injection valve L installed in the lift sensor 7, as shown in the center of the diagram (B). Although the voltage level is relatively small, the pressure of the pumped fuel also increases as the engine speed and load increase, so the abnormal signal component 80.2, as well as the normal signal component soi, increases the engine speed and load. As the voltage increases, the voltage level also increases. However, since the detection level S of the lift sensor signal S is fixed at a predetermined voltage level, for example, a voltage level matched to the minimum rotation of the engine,
As shown in FIGS. 1C and 1P, as the engine speed, load, etc. increase, abnormal signal components from other cylinders are also measured. Historically, since this abnormal signal component is accompanied by a propagation delay, the injection timing and offset amount T detected by the abnormal signal component Sθ- are equal to the normal signal component 80/
However, a difference occurs between the injection timing and the offset temperature T/ that is detected. Therefore, the detection accuracy of injection timing deteriorates,
Control performance will be impaired.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a means for making the detection level of the lift sensor signal obtained from the lift sensor variable depending on the operating state of the engine, thereby making it possible to accurately measure fuel injection timing. An object of the present invention is to provide a fuel injection timing measuring device for a diesel engine.

Another purpose of this invention is to provide a means for selectively extracting only the foot sensor signals that occur within a predetermined crank angle range, thereby determining the accurate fuel injection timing in a diesel engine. An object of the present invention is to provide a fuel injection timing measuring device.

Hereinafter, the present invention will be explained in detail based on the drawings.

Incidentally, since the fuel injection valve used in the present invention has the same configuration as that shown in FIG. 1, detailed explanation will be omitted.

FIG. 3 shows an example of a fuel injection timing measuring device to which the present invention is applied, and FIGS. (4) to (D) show waveforms of signals output from each component of this measuring device. Here, λl is an amplifier circuit having a differential amplifier and a resistor, which amplifies the lift sensor signal Bi of the above-mentioned lift sensor 7 disposed in the fuel injector, and its amplified signal 86 ( (see the solid line in section (B)) is supplied to one terminal of the comparison (b) path. n is a crank angle sensor, which generates a spiral crank angle signal S (see Fig. 5) at a predetermined angular position of the crankshaft, and this signal 941 is sent to a frequency-to-voltage converter (hereinafter referred to as F-vzI!8) is supplied to the terminal R of the flip-flop J
supply to.

The F-V converter has an operational term, a resistor, and a capacitor, and the crank angle signal S of the crank angle sensor n.
A signal 8 whose voltage level is directly proportional to its frequency? (
(see the broken line in FIG.

Comparison tgllIi1! - is constituted by a comparator of an integrated circuit (IC) such as MC330/, which compares the signal S6 supplied from the amplifier -2 with the variable voltage level signal S supplied from the F=V converter J. That signal S
6 is at a higher voltage level than signal S7, the detection signal 8
JC1g4' (see figure (C)) is output, and this signal S1 is supplied to the set terminal S of the 7 lip-flop j.

The flip-flop J is connected to the above-mentioned detection signal sg and the crank angle signal needle, and generates a signal 8 de (No.
reference) is output.

In the fuel injection timing measurement device i1 for the fuel injection valve configured as described above, the lift sensor signal S/ generated in response to a change in the load applied to the lift sensor 7 with the opening of the fuel injection valve l is detected from the lift sensor sensor. taken out.

This signal S/ is supplied to the amplifier circuit -/ and the result is 4' IJ.
A signal 84f as shown by the concentrated line in (B) is obtained.゛This signal S6 includes a normal signal component 8 indicating the displacement of the needle valve J of the fuel injection valve/, which is arranged with a lift sensor as described above.
In addition to 4/, 86 abnormal signal components caused by the displacement of the needle valve of the fuel injection valve of the adjacent cylinder are included.

On the other hand, the angle signal 84 output from the crank angle sensor
The F-V converter converts the signal into a variable voltage level signal 87 directly proportional to the frequency of the signal S7, and supplies this signal S7 to a comparator circuit 2. .

Next, a comparison circuit compares the amplified signal S6 with the variable voltage level signal 8 to obtain a detection signal S1 as shown in FIG. At this time, an F-V converter is used in advance so that the variable voltage level signal S becomes equal to the voltage level of the abnormal signal component SAu. ! 11, abnormal signal components are removed and only normal signal components are included in the detection signal Sl.

Subsequently, the above-mentioned detection signal S1 and angle signal S+ are supplied to the flip-flop. By flip-flop 8,
Measurement signal 89 is guided to one stable state @H'' level by human input of signal S1, and is guided to the other stable state @L'' level by input of signal By.
get. This signal S9 is, as shown in Fig.
During the v level, TI becomes the offset amount from the start of operation of the fuel injection valve l to the reference angular position, so the pulse @T
ii measurement allows accurate detection of injection timing. In other words, since the F-V converter Koda is provided as a means to vary the detection level S7 of the lift sensor signal S+ or its amplified signal 84 according to the engine operating condition, only desired normal signal components are detected. This makes it possible to accurately measure injection timing, etc., and to significantly improve controllability.

FIG. 5 shows another example of the fuel injection timing #j fixing device to which the present invention is applied, and FIG. 6 shows the waveforms of signals output from each component of the measuring device. .

Here, 3/ is a comparator, and this comparator No. 3/11 is supplied to one terminal from the knot sensor 7. 1) Foot sensor signal B/C7l (see the solid line in Figure 4 (b)), and others A predetermined comparison voltage level signal S (see the broken line in FIG.
(see drawing) and supplies this signal sii to the set terminals S of three 71-knop flops. The flip-flop here is kept at the "H" level, which is a stable state, by inputting the detection signal Bit.This is the first crank angle sensor 3.
3 to the reset terminal 8 (see FIG. 6(B)), the signal 813 (see FIG. 1(B)) is returned to the @L'' level, which is the stable state of
(see F)) and supplies this signal si3 to one terminal of the AND circuit 3da.

The first crank angle sensor 3J is a reference angle of the crankshaft corresponding to the number of cylinders, for example, 12θ0 in the case of a 6-cylinder engine.
A pulse signal S saw is generated for each angle of , and the 0° angle signal S/ko is supplied to the flip-flop 3- and also to one terminal of the 113 frequency divider circuit 3j. J4 is a second crank angle sensor, and this sensor J4 generates a pulse signal f3i+ (see FIG. 6 (4)) at every predetermined angle of the crankshaft of the cylinder in which the lift sensor 7 is disposed, for example, every angle of 7-0 degrees. This 7200 angle signal 5zet
It is supplied to the other terminal of the J frequency divider circuit 3j.

The 3-frequency divider circuit 3j is composed of a 7-lip 70-tube IC such as CD 0027, and after being reset in Figure JII4 (as shown by C1, by the 7x0° angle signal 8/da),
7. Open the gate with the pulse of the 200 angle signal S/- @
The signal S/j goes to the H" level, closes the gate with the J-th pulse of the signal 8/co and returns to the 1L" level, and outputs this signal S/j to the AND circuit J4'. Supplied to the other terminal of AND circuit 3
The signal 8/ supplied by the terminal from three flip-flops
3 and the signal S/j supplied from the frequency divider circuit 3j, and outputs a #J constant signal 816 (see the sixth drawing).

With the above configuration, when the lift sensor signal 8/ of the lift sensor 7 and the level signal S2 of a predetermined voltage (for example, O, S■) are supplied to the comparator 3/, the output from the comparator 3/ is A shaped signal 8// as shown in FIG. 6 (Q) is obtained. This shaped signal Sl/ and l of the first crank angle sensor 33 are
The angle signal S/- is supplied to three 7-lip flops to obtain an output signal 8/J as shown in factor 6).

Furthermore, the first crank angle sensor l-〇〇 angle signal 8/co and the jllJ crank angle sensor 34's 7-θ° angle signal 8/
4/L is supplied to the frequency divider circuit 33 to obtain a signal S/3 that maintains a predetermined rank angle range $T,7 at @H'' level as shown in FIG. 6(C). The signal S/j and the output signal 8/J of the flip-flop 32 are supplied to only an AND circuit and a logical product is performed to obtain an output signal 814 from which abnormal signal components have been removed as shown in FIG. That is, since the pulse @T3 of the signal sis mentioned above is predetermined within the range in which normal signal components occur, this signal S/j
By performing the AND with the output signal 8/J of the three 7-lip-flops, the abnormal signal component can be removed, and the normal foot sensor signal component occurring in the section T3 within the Kannai section of the Kuko O0 section of the crankshaft. can only be detected.

Therefore, in the signal S/A, the offset amount TI from the injection start timing (valve opening timing) TB to the reference angle TF
can be accurately measured by counting the clock pulse (one stitch, not shown) between them.

Above [I! As has been explained, according to the present invention, by changing the comparison voltage level depending on the operating conditions or by detecting only the injector lift signal that occurs within a predetermined angular interval of the crank angle, Since the injection period is set so that it can be detected, the signal component from the adjacent injection valve, which is an abnormal component included in the output signal of the lift sensor, can be removed, and only the effective component can be detected. Therefore,
The fuel injection timing of a fuel injector of a diesel engine can be detected accurately, thereby achieving high precision and good control performance in injection timing control.

[Brief explanation of the drawing]

゛Figure 1 is a sectional view showing seven examples of fuel injection valves with lift sensors used in the present invention, and Figures 2 (4) to (D) are waveform diagrams showing output signals from each terminal of the conventional device. , FIG. 3 is a block diagram showing an example of a device to which the present invention is applied,
Sections (4) to ■) are waveform diagrams showing the output signals from each terminal. Figures 11b to 11b (Q) of the block diagram showing another example of a device that has been used in eight applications are waveform diagrams showing output signals from each terminal. /...Fuel injection valve, C...Fuel supply passage, J
...needle valve, da...nozzle hole, j...spring, le...ground plate, r...lift sensor, 1.p electrode, J/...amplifier circuit,
n...comparison circuit, n...crank angle angle sensor, review...F-V converter, correction...slip flop, 31...comparator, 3 pieces...flip flop, J3 ...First crank angle sensor 1. 741...AND circuit, 3j...3 frequency divider circuit, 3t...1st co-crank angle senna. Patent applicant Nissan Motor Co., Ltd./ /Al'*

Claims (1)

[Claims] 1) A stop sensor that outputs a first signal corresponding to the displacement of the needle valve of the fuel injection valve, and a first signal that outputs a voltage level that changes depending on the operating conditions of the engine. means for comparing the first signal with the first signal to obtain a signal of ts3 corresponding to the opening of the fuel injection valve, A fuel injection timing measuring device for a diesel engine whose IvI image is to detect the injection timing of a FI2 fuel injection valve. 2) A lift sensor that outputs a first signal corresponding to the displacement of the needle valve of the fuel injection valve, and a seventh crank angle sensor that outputs a first signal that corresponds to the top dead center position trap of a predetermined cylinder of the engine. a first crank angle sensor that outputs a third signal corresponding to a reference angular position of the crankshaft; and a first crank angle sensor that outputs a third signal corresponding to a reference angular position of the crankshaft; and a means for outputting a second signal, and the injection timing of the fuel injection valve is detected based on the first signal and the first signal. Timing measuring device.