JPS5932668A - Lift detector for fuel injection valve for internal-combustion engine - Google Patents

Abstract

PURPOSE:To permit to detect the amount of the lift of a needle valve, which is corresponding to each operating conditions by a method wherein the detecting level of a needle valve lifting signal is changed in accordance with the operating condition of the engine. CONSTITUTION:An input terminal, earthed through the resistor R2 of a comparator COM, is provided with the input of a sensor or the needle valve lifting signal through an input resistor R1 while the other input terminal is provided with the revolution signal of the engine through a F-V convertor FV. The signal, provided through the convertor FV, has a character as a reference signal to be compared with the needle valve lifting signal and, therefore, the level thereof is increased when the revolving number of the engine is increased while the level thereof is decreased when the revolving number of the engine is reduced. Accordingly, the high-level reference signal is provided to the comparator upon the normal operation of the engine and the low-level reference signal is provided to the comparator upon starting and the extremely low-speed revolution of the engine, therefore, noise in the input of the sensor is not detected upon the normal operation of the engine while the input of the sensor, which is having a low- level upon starting or the like of the engine, may be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection tank lift detection circuit for an internal combustion engine.

In recent years, the electronic engine control type fuel injection system has become widely used to control the fuel supply of internal combustion engines. There is a system in which the fuel injection amount is controlled by controlling according to the 1t!1 engine load.

Here, enlargement causes changes in the injection properties due to long-term use. For example, the lift amount for enlargement changes due to wear of the needle valve, and there is a corresponding relationship with this lift h17. )l
Tjil, by causing a change in volume.

Therefore, the injection nozzle is equipped with an element that detects the valve lift, such as a pressure-sensitive element, and the valve opening time is adjusted based on the detection signal of this element. A configuration has been proposed that will control the amount of fuel injection over a period of time.

This configuration will be explained with reference to FIGS. 1 and 2. 1
-/In other words, the fuel core (the yarn is supplied with fuel from the bonder 11)
12 and then supply the furnace 4) to the nozzle 13. +14 is made as shown in 4) 'CC60, the actuation of the bonder 11] -
”-Itoyo 11a is tl;Ii control circuit 14! l) If the control A is turned on, the fuel supply is carried out according to the operation 1-L). The fli control circuit 14 has an engine speed of 9 engine'f] load picture (, ¥ and Jt:fc yt!
Actico-T, -ta 1'1~ from the sensor 111)
The control signal is formed using the jtlJ signal 5 and the valve control signal 11 from the nozzle 13. This four-valve lift signal is formed by a needle valve lift sensor 15 provided at the base of the nozzle 130, which has a value corresponding to the lift ha of the nozzle 13 (as Ut).

/ Suru 13 &! , fuel 1f4 supply pipe 12 and nosulpolda 21. Contact piece 22. Nozzle body 16
When the fuel pressure applied to the chute valve 18 through the fuel passages 17 formed inside each reaches a predetermined value or more, the chute valve 18 is biased by a spring 20 which is biased by a slider washer 19 at the top thereof. The nozzle body 1 is pushed up against the acting force of
High-pressure fuel is injected through injection holes A and 16a'IJ- formed in the bottom wall of 16. In this case, the foot sensor 1 stretches the top surface of the washer 19 when the lift amount of the needle valve 1B increases beyond a certain level.
The rod 15a of No. 5 comes into contact with the bottom 1rrl of the rod 15a and presses it, and a signal corresponding to this pressure ('': or stroke ffl) and time is generated. Got this? t
The i control circuit 14 forms a control signal that reflects the four-valve lift M, and stable fuel injection amount control is performed over a long period of time.

However, there are the following problems with the already proposed divine head. The output of the enlarging engine 15 is leaked to a comparator with a constant reference value, but the output of the enlargement engine 15 is leaked to a comparator with a constant reference value. Fluctuations in the level may cause false detection, etc.In addition, when the engine starts or rotates at extremely low speed, the injection pressure is low (needle valve lift (%i is the 31st
As shown in 70a), the peak value is only about 1.5 to 2.0V, but normally j11 (transformation o4 is shown in Figure 3 (1)
), the peak value is about 5 to 20V, and on the other hand, the noise generated by the high-frequency vibrations of the engine and the noise produced by the valves can even reach several volts.

If this is detected by the comparator COM with IJ and standard value Vs constant as shown in Fig. 4, the detection temperature will be 7, (
, squid or redundant operation 1 (6) will also detect noise, making it impossible to perform a control operation that accurately takes into account the fuel injection operation (11-).

The present invention was developed in consideration of the above-mentioned points, and the 4-valve lift was made by changing the inspection bell of the side valve lift IA according to the operating state of the engine and adjusting the iL for each operating state. ,
, J(j) 3. To achieve this objective, the present invention adjusts the relative level of the needle valve lift signal and the reference signal depending on the operating state of the engine. This circuit constitutes a circuit that can accurately detect the amount of lift of the side valve by changing the amount of lift of the side valve.

The present invention will be explained below with reference to the embodiments shown in FIGS. 5 and 6.

FIG. 5 shows an embodiment of the present invention, in which the comparator CO
The sensor input side valve lift signal is given to the human input terminal grounded via the resistor 112 of M via the input resistor R1, and the other input terminal is provided with the F-V (frequency-voltage converter FV cable). The rotation signal of the engine is configured to leak through the converter 1i'V. The level increases as the engine speed increases, and decreases as the engine speed decreases.

Therefore, a high-level reference signal is given to the comparator during regular engine operation, and a low-level reference signal is given to the comparator during startup and extremely low-speed rotation, and in the event that noise is not detected in the sensor input during normal operation and the engine is started. It is also possible to detect low-level sensor inputs such as time.

FIG. 6 shows another embodiment of the present invention, in which the comparator C
A reference voltage source Vs is connected to the reference power terminal of the OM through a resistor R13, and this human power terminal is connected to a resistor (1
4 and the switch SW,
The level of the reference signal is changed by opening and closing the switch sw. If a start switch is used with switches SW and l-, the level of the reference signal will be lowered at the time of starting.

In the above embodiment, the level of the reference signal is changed, but the level of the sensor input may also be changed. For example, the resistance value of the grounding resistor Rz of the input terminal to which the sensor input is applied 1-) can be changed.7. ), and then change the resistance value of resistor (, 2) depending on the operating condition of the engine.In short, the level of either the reference signal or the side valve lift signal can be changed depending on the operating condition of the engine. The relative level relationship between both signals may be adjusted by

As described above, the present invention changes the detection level of the 4-valve lift signal depending on the operating state of the engine, so that there is no false detection of noise during normal operation, and moreover, it is possible to perform constant pressure enlargement at startup. Detected SF 13.

It is possible to provide a fuel injection valve lift detection circuit that never fails. Therefore, it is possible to perform precise fuel injection control over the entire rotation range of one engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the previously proposed fuel injection control system, and FIG. Figure 3 (a
), (b)i 1 waveform diagram showing the 4-valve lift signal obtained by the valve in Fig. 2, Fig. 4 shows the 4-valve lift signal obtained by the valve in Fig. 3 (a), (b)
) shows a detection circuit for bird leakage.
3 Explanatory drawings, FIGS. 5 and 6 show embodiments of the present invention 1
It is a circuit diagram. 15... Needle valve lit sensor 17... Fuel passage 1
8... Needle valve COM... Comparator Vs... Reference voltage source SW... Switch Patent applicant Japan Electronics Co., Ltd. Figure 1 Figure 2 Figure 3 (a) 3r = ++ (b ) Noise゛□ Figure 4 Figure 5 +゛< Figure 6

Claims (1)

[Claims] The fuel injection nozzle is provided with an enlarger that lifts against the spring force when the pressurized fuel leaks out due to being biased by the spring force. ii'i:
A type 1 valve lift detection circuit for an internal combustion engine is configured to detect the output of the sensor (or /, -) or the reference signal depending on the operating state of the engine. Internal combustion engine l8''; fuel injection valve lift detection device.