JPS59190436A - Control unit of electronic fuel injection device - Google Patents

Abstract

PURPOSE:To decrease the number of ring gears determining the crank angle by determining the fuel injection start timing and fuel injection end timing in response to the time from the top dead point. CONSTITUTION:A pulse ring gear 3 is fitted to the crankshaft 2 of an internal- combustion engine, and a tooth 4a detecting the top dead point of the engine is provided on a cam shaft 4. The rotation of the tooth 3a fitted to the ring gear 3 is detected by a solenoid pickup 5, and the engine rotating speed is calculated. The fuel injection start timing and end timing are stored in terms of the crank angle from the top dead point. They are converted into the time from the top dead point by using the engine rotating speed, and the above time is counted from the top dead point signal generation time of the solenoid pickup corresponding to the tooth 4a. Accordingly, the number of ring gears can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electronic fuel injection system in an internal combustion engine equipped with a fuel injection valve, which controls the injection timing of the fuel injection valve without directly using a crank angle signal.

Conventionally, electronic fuel injection systems have an electrohydraulic valve mechanism built into the fuel injection valve body, and the amount of time the solenoid is energized determines the injection amount. p is detected by an electromagnetic pickup, and the timing of fuel injection is determined based on this. .

However, when directly using the angle signal from the crankshaft to detect fuel injection timing, in order to control the injection timing to within 0 in terms of crank angle, it is necessary to incorporate a crank angle signal within 1°. Therefore, the number of teeth of the pulse ring gear needs to be 360 or more, which has the drawback of increasing the processing cost of the nockle ring gear. .

The purpose of this invention is to eliminate the drawbacks of the conventional electronic fuel injection device, reduce the number of teeth of the pulse ring gear on the crankshaft, and increase the detection accuracy of the rotation angle of the crankshaft to within 1 degree. An object of the present invention is to provide an excellent control device for an electronic fuel injection device that can be used in a controlled manner.

In order to achieve the above object, the electronic fuel injection device control device of the present invention detects an engine TOP mark provided on a camshaft, detects an arbitrary number of marks provided on an arbitrary rotating shaft, and detects an arbitrary number of marks provided on an arbitrary rotating shaft. means for calculating the engine speed from the required time or the number of marks detected within a certain period of time, means for setting the engine speed, engine speed, and optimal injection timing (angle from the TOP mark) corresponding to the injection amount. and calculates the necessary fuel injection amount in the form of energization time to the solenoid according to the rotation speed deviation in order to make the engine rotation speed match the target value, and each time the TOP mark is detected, Convert the optimal injection timing table value to the time required from the mark point to point 1 to inject, and after waiting for a time equal to the energization time subtracted from that value, start energizing the solenoid. It is characterized by having calculation and control output means.

The present invention will be described in detail below using the drawings.

FIG. 1 is a configuration explanatory diagram of an embodiment of a control device for an electronic fuel injection device according to the present invention.3 A pulse ring gear 6 is attached to a crankshaft 2 of an internal combustion engine, and an X A number of plates 3a are provided. In this embodiment, one tooth 4a is provided on the camshaft 4 at the engine TOP position.

Electromagnetic pickups 5 and 6 are installed at positions facing the teeth 6a and 4λ, respectively, and their outputs are waveform-shaped by Schmitt circuits 7 and 8, and the output of the electromagnetic pickup 5 is sent to the gate of the microcomputer 1a. The output of the electromagnetic pickup 6 (
Similarly, the input is made to the second interrupt terminal 111 of the CPU 11 of the microcomputer 10. This microcomputer has a 12° ROM on the I10 board connected via the Tebas line 20
13. RAM 14. A second counter and a latch circuit 19 are built-in. This microcomputer 10K is provided with an oscillator 15 that oscillates at a frequency of 1, and its output is input to the first counter 16. 16 is the gate generation circuit 18 and the latch circuit 1
The gate generation circuit 18 is further connected to the first interrupt terminal 11a of the CPU 11.

In addition to the electromagnetic pickups 5 and 6 connected to the microcomputer 10 configured as described above, an engine speed setting device 9 is connected to the boat 12, and a second counter 17 is connected to the engine speed setting device 9. is connected to the base of the transistor Q1 via the drive circuit 26. This transistor Q
When the solenoid 1 is turned on, the solenoid 21 connected to the solenoid 1 is energized, and an electromagnetic hydraulic valve (not shown) built in the fuel injection valve 22 is opened to inject fuel from the fuel injection valve 22.

The control device for the electronic fuel injection device of the present invention is configured as described above, and when the internal combustion engine is in operation, the crankshaft 2
Every time the X teeth 6a provided above pass the electromagnetic pickup 5, an output signal from the electromagnetic pickup 5 whose waveform has been shaped by the Schmitt circuit 7 is input to the gate generation circuit 18. Every time one tooth 4a located at the engine TOP position on the shaft 4 passes the electromagnetic pickup 6, its output signal is sent to the second interrupt of the CPUII via the Schmitt circuit 8 in the same way as described above. 2 is applied manually to the terminal 11b.

On the other hand, a pulse signal of frequency n is always input from the oscillator 15 to the first counter 16, and the gate generation circuit 18
From then on, when y teeth 6a on the crankshaft 2 pass through the electromagnetic pickup 5, a signal is sent to the first interrupt terminal 11a of the VCCP TJ 11 and the first counter 16.
The number is now entered. Upon receiving this signal, the first counter 16 sends the value it was counting at the moment to the launch circuit 19 and starts counting the pulse signal from the oscillator 15 anew. , here, the number of teeth 6a on the second shaft 2, the oscillation frequency of the oscillator 15? ?
and the number y of teeth 6a to which the gate generation circuit 18 sends output
i is a known number.

From the above, the time T required for two rotations of the engine is as shown in the following formula 1, T""-X+nX-'X2 (secl...
-(T)IL y (where m is the number of pulses from the oscillator 15 that are input while y teeth 6a pass) The engine rotation speed N is expressed by the following equation (2).

N=60/(-'-X7nX engineering) [rpm]...
・■ny Set the injection timing at the crank angle from the engine TOP to θC0A −
TDC], the injection may be performed after a time t1 [seC] after the engine TOP signal is input. This time t1 is determined by the following equation (2).

tl-(±X m X-'-X2)
ec':] = ■TL 3F Furthermore, if the set speed is N1, the fuel injection amount Q and the energization time t2 to the solenoid 21 required to control the engine rotational speed N to the set speed N1 are expressed as in the following equation (■). It will be done.

t2== PI X Q := PI XP2 X (
N-N1) C5ec]-・■ (However, PI and P2 are constants) In this invention, the signal from the speed setting device 9 is input to the CPU 11 through the board 12, and settings corresponding to the signal are made. Send speed N1 to RAM14. When y teeth on the crankshaft 2 pass the electromagnetic pickup 5, a signal is input from the gate generation circuit 18 to the first interrupt terminal 11a of C1)Ull, and the first counter 16 obtains The number m of oscillation pulses is taken in from the latch circuit 19, and the engine rotation speed N and the solenoid 2 are calculated from the above formula (■).
Calculate the energization time t2 to 1. Then R
Does it communicate with the engine rotation speed N stored in OM 13?
The optimum injection timing θ[0A for time t2.

3. Load TDC':l into CPU 11. The energization time t2 of the solenoid 21 determines the injection amount of the fuel injection valve 22.

6. Also, calculate the time L1 from the above formula 0, calculate the trace current closing (or cutoff start) time t3 from t3 - t2 - tl, and send it to the RAM 14.6. In this way, the time t1.5 is set at 11j' when y pieces of paper pass. The pulse of the 11th ancient 1st century (
j) Ull's 2nd 'l! +'J terminal 111) person)
Node dt, RA, M-14 to said time t1.
t・3k l1tt ・Send 1 to the second counter 17. Then, the output of the second counter 17 is shaped by the drive circuit 26 consisting of a flip-flop, etc., and the signal is sent to the transistor Q1. A pulse with injection timing θ1 and energization time t2 shown in FIG. 2 is applied to this transistor Q1, and transistor Q1 is turned on only during that time.

The signal sent to the transistor Q1 is a drive signal for a voltage-hydraulic valve mechanism in which the energization time t2 determines the injection amount, and the end of the energization time L2 determines the injection timing4.If the current is cut off, If time determines the injection amount and the end of the cutoff time determines the injection timing, this signal may be inverted.

Here, the gate generation circuit 18 outputs a signal.
If the number y of a is decreased, the accuracy of the engine rotation speed and injection timing will increase, but it will take a longer time to calculate the engine rotation speed and injection timing. Therefore, the number y may be determined in consideration of the desired accuracy.

In addition, in this example, pulse 1) is applied to crankshaft 2.
A gear 6 is attached to the gear 1, and seven teeth 6a are provided on it, but the gear 6a does not have to be on the crankshaft 2 and can be attached to any other rotational shaft linked to the crankshaft 2. 3. May be provided. Further, the equations for determining the fuel injection amount Q and the energization time t2 of the solenoid 1-21'' for controlling the engine speed to the set speed are not limited to the above-mentioned equation 0.

As described above, in this invention, the crank angle can be accurately and accurately detected without directly using the angle detection teeth provided on the crankshaft, so the number of teeth provided on the crankshaft is small. FIG. 3 is an explanatory view of the main part of another embodiment of the present invention, and is intended to increase the speed of operation of the solenoid 21.

In this embodiment, the pulse signal manually applied to the base of the transistor Q1 is not a single pulse as in the previous embodiment, but a composite pulse as shown in FIG. That is, time T
The CPU 11 sends a command to the second counter 17 to output a pulse with a duty ratio of 00% when it reaches 1, and then sends a command to output a pulse with a certain duty ratio when time T2 comes. , the voltage at point A on the emitter side of the transistor Q1 for a period of time T3 is measured by an integrating circuit 24 constituted by a resistor R and a capacitor C, and A installed in the microcomputer 10.
/D converter 25, and RAM 1.
! Store in l. The voltage at point A will be higher if there is more current flowing through the solenoid 21, and lower if it is less, depending on the resistor R3 installed between point A and the ground.
It can be used as a substitute for the value of the current flowing through the wire/ite 21.

Then, the voltage value at point A with respect to the holding current of the on-state of the solenoid 21 obtained in advance is stored in the ROM 13.
) and compare it with the current voltage at point A. If the current voltage at point A is lower than the value held when the solenoid 21 is in the on state, a correction command is sent to the second counter 17 to increase the duty ratio, and if it is higher, to decrease it. This duty ratio changes the current value flowing through the solenoid 21; if the duty ratio is made large, the current value becomes large, and if the duty ratio is made small, the current value becomes small. Then, at time T3, the CPU 11 sends a command to the second counter 17 to send a pulse with a 0% tute ratio.If such control is performed, the waveform of the current flowing through the solenoid 21 will be as shown in FIG. It becomes like this. It is assumed that the resistors used in the circuit generate almost no heat.

As a result, the current rises quickly from time T1 to time T2. Since the current value is constantly read and corrected from time T2 to time T3, the current decreases due to heat generation of the wire/ite 21. Even if there is a change in current due to a change in power supply voltage, the average value of the current flowing at this time can be set as the on-state holding current of the solenoid.

Therefore, in the control device for the electronic fuel injection device of this embodiment, it is possible to reduce the heat generation of the solenoid and increase the speed of the solenoid operation using a single power source, thereby achieving power saving.

As explained above, the electronic fuel injection device control device of the present invention is capable of controlling the injection timing of the fuel injector in an internal combustion engine equipped with the fuel injector without directly using the crank angle. This eliminates the need to provide a large number of teeth for detecting the crank angle on the crankshaft, which has the effect of reducing processing costs.

[Brief explanation of drawings]

1 is a configuration explanatory diagram of one embodiment of the control device for an electronic fuel injection device of the present invention, FIG. 2 is a pulse waveform diagram at a predetermined location in FIG. 1, and FIG. FIG. 4 is a diagram showing the drive pulse waveform of the transistor shown in FIG. 3, and FIG. 5 is a diagram showing the waveform of the current flowing through the solenoid shown in FIG. 3. 2... Crankshaft, 6... Pulse ring gear, 6a
. 4a... Teeth, 4... Camshaft, 5, 6... Electromagnetic pickup, 9... Speed setter, 10... Microcomputer, 1l-CPU '1 11 a-... No. 1 interrupt terminal, 11b...2nd interrupt terminal, 12...11
0 port, 16...ROM114...RAM,
15... Oscillator, 16... First J counter, 17.
...Second Kaunk, 18...Cate generation] Road, 19
・・・Lunch circuit, 20...ノ(Sline, 21...
・Solenoid, 22...Fuel injection valve, 26...Drive circuit, 24...Integrator circuit, 25...A/D: INNO<IO Agent Patent Attorney Shin Ogawa - Patent Attorney Noguchi Teru Ken Patent Attorney Kazuhiko Saishita

Claims (1)

[Scope of Claims] 1. A control device for an electronic fuel injection device in which an electrohydraulic valve mechanism is built into the fuel injection valve body, the time when the solenoid of this mechanism is energized determines the injection amount, and the time when the energization ends is the injection timing. A means for detecting the engine TOP mark provided on the camshaft, a means for calculating the engine speed based on the mark provided on an arbitrary rotating shaft, a means for setting the target engine speed, and a means corresponding to the engine speed and the injection amount. means for storing the optimal injection timing determined by the engine; means for calculating a fuel injection amount according to the deviation between the target engine speed and the actual engine speed in the form of the energization time of a pulse to the solenoid; A control device for an electronic fuel injection system, comprising means for converting the optimum injection timing into a required time from a TOP mark point, and calculating a time to start energizing a solenoid from the energization time and the required time. 2. The control device for an electronic fuel injection device according to claim 1, wherein the pulse for energizing the solenoid every time the T Ol) mark is detected is one pulse. 3 The pulse that energizes the solenoid every time the TOP mark is detected is a continuous pulse, the initial pulse width is wide so that the current flows continuously through the solenoid for a predetermined time, and the pulse width of the subsequent continuous pulses is 2. The control device for an electronic fuel injection device according to claim 1, wherein the pulse width is modulated to match the energization state holding current value.