JPS60249653A - Injection amount controller for fuel injection pump - Google Patents

Abstract

PURPOSE:To control injection amount always with high accuracy by installing an angular signal detector which can detect the minute angular pulses over several-thousands pulses per revolution onto a pump shaft and controlling an electromagnetic spill valve by counting the above-sescribed pulses. CONSTITUTION:An angular-signal detector 1 is equipped with a disc 101 made of nonmagnetic material which has, on the outer periphery, a magnetic member 102 for magnetic record which has the interval between a pair of magnetic poles of 10mum or so, and fitted and fixed onto the rotary shaft of a fuel injection pump. Each signal can be detected at each pump revolution angle, e.g., at each 0.03 deg. by detecting the magnetic member 102 by a magnetic head 103. Therefore, an electromagnetic spill valve (not shown in the figure) is opened by the signal at the n1-th of the standard position and closed by the n2-th signal, and the error due to the variation of revolution can be reduced to zero. Since the injection time in one time of the pump is 10 deg. or so, fuel injection amount can be adjusted withan accuacy of 0.3%.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an injection amount control device for a fuel injection pump.

(Prior Art) In a conventional electromagnetic valve spill type fuel injection amount control device for a diesel engine as shown in Japanese Patent Application Laid-Open No. 58-183826, 1. As shown in Fig. 2, a reference position signal generator is attached to the pump, and the elapsed time from the reference position is
The opening and closing timing of the electromagnetic spill valve is controlled to precisely control the injection amount. For example, as shown in FIG. 3, the electromagnetic spill valve is controlled to open after a time of 1° from the reference position To, and to close after a time t2.

(Purpose of the Invention) The present invention further improves the conventional device by attaching an angle signal detector capable of detecting minute angular pulses of several thousand pulses or more per revolution to the rotating shaft of the pump, and counting these minute angular pulses. By opening and closing the electromagnetic spill valve at the desired crank angle position, the injection amount can be controlled even when the relationship between the rotating crank angle and time changes due to sudden engine acceleration/deceleration or rotation fluctuations for each explosion. The purpose is to enable highly accurate control.

For example, the angle signal detector 1 shown in FIG.
) Diameter 4. (A magnetic material 102 for magnetic recording is installed on the outer periphery of a disk or cylinder 101 made of a non-magnetic material with a diameter of approximately At this time, N
If the spacing between the magnetic poles of S-set is set to about 10 μm, φ4
Approximately 12,000 pairs of magnetic poles can be recorded on the outer periphery of the disk of Qm+a. If this is detected by the magnetic head 103, one signal can be detected for every 0.03° of pump rotation angle. Therefore, as shown in Fig. 5, from the reference position n1
If control is performed such that the valve opens at the second signal and closes at the n2th signal, errors due to rotational fluctuations will not occur. The injection period of one pump is 10 at the maximum injection amount.
Since it is approximately 0.03°, if control is performed using a signal every 0.03°, the injection amount can be adjusted with an accuracy of 0.3% of the maximum injection amount.

(Example) The present invention will be explained below with reference to an embodiment shown in the drawings.

Figure 1 shows the configuration of this system. Reference numeral 3 denotes a rotation speed detector, which utilizes a known electromagnetic pink amplifier, and is mounted opposite to a gear that rotates in conjunction with the rotation of the engine or injection pump.

4 is an accelerator position detector, which uses a potentiometer or the like. Reference numeral 5 denotes other operating state detectors, such as an intake pressure detector, a cooling water temperature detector, and a battery voltage detector. 2 is a reference position detector, which detects the rotation reference position of the pump; for example, in the case of a distribution type injection pump for a 4-cylinder engine, four protrusions are provided on the face cam or the plunger shaft, and the The reference position is detected by installing a Hall element, a magnetoresistive element, a photodetector, etc. 1 is the angle signal detector mentioned above, as shown in Fig. 4 (a
As shown in FIG. 1, a disk or cylinder 10 made of a non-magnetic material
1. A magnetic material 102 for magnetic recording is installed on the outer periphery of the magnetic material 10.
2, recording as shown in FIG. 4(b) is performed by a known magnetic recording means. This can be done using an electromagnetic method, or a Hall element.
It is detected by a magnetic head 103 that uses a magnetoresistive element or the like. Here, the diameter of the disk 101 is about 40 mm, and 12,000 sets of magnetic poles are recorded on the outer periphery, so the interval between one set of N-3 magnetic poles is about 10 μm as shown in FIG. The fuel injection pump is, for example, a distribution type injection pump as shown in FIG.
include.

This pump 6 pressurizes fuel sucked in from an intake port 69 by a plush 62 that rotates and reciprocates by a face cam 63 in a pump chamber 65 serving as a pressurizing chamber.
It is of a type in which the air is fed under pressure from a distribution port 65 to each cylinder to a nozzle via a suction valve 64.

In the present invention, in addition to the above configuration, a solenoid valve 61 is arranged at one end of an overflow port (overflow passage) 67 which is constantly connected to the pressure of the pump chamber 65, and when this solenoid valve is opened, the pump High pressure fuel in chamber 65 is allowed to overflow into low pressure housing 70 via passages 67a, 70a.

20 is an electronic control unit (hereinafter referred to as ECU), which includes an electronic circuit 22 centered on a microcomputer 21.
It consists of ~33.

The signal from the rotation speed detector 3 is converted into a rectangular wave by the waveform shaping circuit 22 and input to the microcomputer 21 .

The microcomputer 21 is set to issue an interrupt at the rising edge or falling edge of the rectangular wave, and calculates the number of revolutions from the cycle of the interrupt.

Analog signals from the accelerator position detector 4 and other driving state detectors 5 are converted into digital signals by the A/D converter 23 and input to the microcomputer 21.

The signal from the angle signal detector 1 is converted into a rectangular wave by the waveform shaping circuit 25 and then input to the counter 27 . The counter 27 is configured to count up by one each time one of the minute angle pulse signals is input. As mentioned above, since the angle signal is outputted with 12,000 pulses per pump rotation, one count of the counter 27 corresponds to a minute rotation angle of 0.03 degrees on the pump shaft. The counter 27 uses a publicly known 16-bit binary counter, for example, TTL IC.

I am using two LS'590s.

The signal from the reference position detector 2 is converted into a rectangular wave by the waveform shaping circuit 24 and input to the reading means 26 and the microcomputer 21. The reading means 26 is structured so that, when a rising edge of a reference position signal shaped into a rectangular wave using a known latch circuit is inputted, the reading means 26 holds the value of the counter 27 at that time. At the same time, the microcomputer 21 is also set to receive the rising edge of the reference position signal and generate an interrupt. The microcomputer 21 can know the contents of the counter at the pump reference position by reading the contents held by the reading means 26 in the separate processing routine.

The microcomputer 21 receives the rotational speed signal.

The target injection amount Q is calculated from the accelerator position signal and other operating status signals. Next, a target valve opening timing 'ro and a target valve closing timing T are determined according to this target injection amount Q. and set the corresponding values in the setting means 28 and 29. This setting means 28, 29 is similar to the reading means 26
I am using IT's lunch.

The previous set value is held until the microcomputer 21 inputs the next set value.

The comparison means 30.31 are constituted by 15-bit digital comparators, and if the values set in the respective setting means 28.29 and the value of the counter 27 match, the output goes high.
h level, and if different, it becomes a low level.

Reference numeral 32 indicates a center reset rotation and has a structure as shown in FIG. When the signal from the comparing means 30 rises, the output becomes Low level, and when the signal from the comparing means 31 rises, the output becomes H7gh level. 33 is a drive circuit for the electromagnetic valve 61, which has a circuit configuration as shown in FIG.

Next, the operation of the microcomputer 21 is shown in FIG.
This will be explained based on the flowchart shown in (E).

When the program starts, initialization is first performed in step 901. Next, in step 902, it is determined whether the engine has been started. For example, the determination can be made based on whether the starter is turned on. If starting is confirmed, the process proceeds to step 904 and the rotational speed is calculated. This is done by generating the rotation speed interrupt shown in FIG. are the current and previous timer counter values TN i, TN i −1
It is calculated by taking the reciprocal and multiplying it by a constant.

Next, in step 905, the accelerator position is detected. The accelerator position signal is A/D converted and taken into the microcomputer as described above. A/D conversion is shown in Figure 9 (
The A/D converter is activated by generating a regular interrupt as shown in C) at a certain time interval, and the 9th
The A/D interrupt shown in Figure (D) is generated as a difference between the values of the timer counter.

Next, in step 906, other operating conditions are calculated. This is calculated by inputting the signals from other operating state detectors 5 using the A/D conversion program as described above.

Next, in step 907, the target injection amount Q is calculated from the information calculated in steps 904 to 906 using a memory map or a calculation formula. At 908, the target valve opening timing 'ro is calculated from the engine speed and the target injection amount. Next, in step 909, the engine rotation speed and the target valve closing timing Tc are determined.
Calculate. The target valve opening timing To and the target valve closing timing Tc
1, the corresponding crank angle positions are calculated as angles from the reference signal.

The program then returns to step 904 and so on.

In this manner, the reference position signal is input to the microcomputer 21 while the routine shown in FIG. 9(A) is being repeatedly calculated. Then, an interrupt occurs and the program jumps to the routine shown in FIG. 9(E). Therefore, the counter value T read into the reading means 26
Load s into the computer 5. Next step 90
The value of TO calculated in step 8 is added to the Ts, and the result is written into the setting means 28. Next, the value of TC calculated in step 909 is added to the Ts, and the result is written into the setting means 29. The program is shown in Figure 9 (
Return to routine A). With the above operation, the solenoid valve 61 can be opened and closed at a desired crank angle position.

FIG. 10 shows waveforms of each part, and the operation will be explained. Figure 10 (A)? The counter value of the counter 27 is increasing as the pump rotates over time.

FIG. 2B shows a reference position signal, which is generated at a predetermined rotation angle position of the pump. At that moment, the reading means 26
The value T5 of the counter 27 at that time is held.

At the same time, an interrupt occurs in the program of the microcomputer 21, and the reference position interrupt routine shown in FIG. 9(E) is executed. Therefore, the setting means 28 has TS+T.
The value of O is set in the setting means 29 as rs+'rCO value. Next, time advances and time 1. Now, plunger 62
starts to lift and fuel injection begins. Next, at time t2, the value set in the setting means 28 and the value of the counter 27 become equal, and the output of the comparison means 30 rises as shown in FIG. At the same time, the output e terminal of the set/reset circuit 32 is connected to the same figure (
It falls as shown in E) and opens the solenoid valve. Then, the fuel injection ends as shown in FIG. 3(F). Next, at time t3, the value of the setting means 29 and the value of the counter 27 become equal, and the output of the comparing means 31 rises as shown in FIG. At the same time, the output terminal e of the cent reset circuit 32 rises, opens the solenoid valve, and prepares for injection in the next cylinder. The injection amount is controlled by repeating the above steps.

In the above embodiment, a solenoid valve that opens when the current is cut off is used, but the same effect can be achieved by using a solenoid valve with the opposite characteristic that opens when the current is applied. In that case, it is necessary to invert the output of the set/reset circuit 32.

In addition, the angle signal detector 1 uses not only a magnetic recording method but also
A detection method using laser light (laser disk, etc.) or a detection method using capacitance (VHD, etc.) may be used.

Further, as the injection pump 6, although a fa-cam type is taken as an example, other types of injection pumps such as an inner-cam type may be used.

(Effects of the Invention) As described above, the present invention has an angle signal detector that detects minute angular pulses attached to the rotating shaft of an injection pump, and by counting these minute angular pulses, electromagnetic waves are generated at a target crank angle position. Since the spill valve is opened and closed, it eliminates control errors at the overflow timing, which is particularly important in electromagnetic valve spill type injection quantity control devices, even during acceleration and deceleration with large rotational fluctuations, ensuring high-precision injection quantity control at all times. can be realized.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a reference position signal generator, FIG. 3 is a timing diagram showing a control method in a conventional control device, and FIG. 4 is a diagram showing an example of a reference position signal generator. FIG. 5 is a diagram showing an example of the angle signal detector in the control device of the present invention, FIG. 5 is a timing diagram showing the control method of the present invention,
FIG. 6 is a sectional view of essential parts showing an example of an injection pump to which the present invention is applied, FIG. 7 is a configuration diagram of the center reset circuit in FIG. 1, and FIG. 8 is a configuration diagram of the drive circuit in FIG. 1. , Figure 9 (A
) to (E) are flowcharts showing the control procedure of the present invention,
FIG. 10 is a timing diagram for explaining the operation of the present invention. 1... Angle signal detector, 2... Reference position detector, 6
... Injection pump, 20 ... Electronic control unit, 21
...Microcomputer, 27...Counter, 6
DESCRIPTION OF SYMBOLS 1... Solenoid valve, 102... Magnetic material, 103... Magnetic head. Representative Patent Attorney Takashi Okabe Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure n Figure 9 (A) Figure 9 (B) (C) (D) (E)

Claims (1)

[Scope of Claims] (11) An injection amount control device for a fuel injection pump that controls the injection amount of fuel by directly overflowing high-pressure fuel in a fuel pressurizing chamber of the fuel injection pump using a solenoid valve, wherein the injection pump rotation axis a reference position detector for detecting a predetermined rotation angle reference position of the pump rotation shaft; an angle signal detector for detecting a minute rotation angle of the pump rotation shaft; and an angle signal detector for counting the minute rotation angle signal from the reference position, An injection amount control device for a fuel injection pump, characterized in that it comprises a control means for controlling valve opening or valve closing timing. (2) The control means counts minute rotation angle signals from the angle signal detector. a reading means for holding the contents of the counter in synchronization with a signal from the reference position detector; a microcomputer for calculating the valve opening or closing timing; The invention further comprises a setting means for holding the counter, and a comparison means for comparing the setting means and the contents of the counter, and the electromagnetic valve is driven in accordance with an output signal from the comparison means. The injection amount control device for a fuel injection pump according to item 1. (3) The scope of the claim is characterized in that the setting means and the comparison means are two, one for opening and one for closing the electromagnetic valve. The injection amount control device for a fuel injection pump according to item 2.