JPS6033990B2 - Rotation speed detection device for electronically controlled fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotational speed detection device for an electronically controlled fuel injection device, which is used in an electronically controlled fuel injection device and detects the engine rotational speed based on an engine operating state other than the actual engine rotational speed.

Conventionally, electronically controlled fuel injection devices have been known as devices that supply fuel to internal combustion engines.This device cuts fuel when the engine decelerates, and increases the amount of fuel when starting or under high load. There is.

This fuel cut and fuel increase are advantageous in that they enable accurate fuel supply to the engine, but since both are related to the engine speed, the means for detecting the engine speed is extremely complicated. That is, a rotation speed detector must be provided to determine the rotation speed range, and a separate comparator must be provided to compare the detected rotation speed with each set value. Further, if the amount of fuel is increased and decreased repeatedly around each set value, engine hunting occurs, so hysteresis must be provided to each set value. As a result, the cost and reliability of the device increases as the number of elements increases. The present invention solves the above problem by generating a pulse signal whose time width changes depending on the engine state such as the starter drive state for starting the engine and the throttle valve function of the engine. By comparing the period of the fuel injection pulse signal synchronized with the engine rotation, various engine speeds can be indirectly detected with a simple configuration, and the hysteresis of low rotation speed settings can be adjusted to high rotation speed settings. To provide a rotation speed detection device for an electronically controlled fuel injection device which can detect the rotation speed in a low rotation speed region by making the value smaller than the hysteresis, and does not increase the cost or reduce the reliability of the device. With the goal.

An embodiment of the present invention shown in the drawings will be described below.

In FIG. 1, 1 is an ignition (IG) coil that detects an engine rotation speed signal in the form of a voltage waveform, 2 is a waveform shaping circuit that shapes the voltage waveform to prevent malfunctions, and 3
is the electromagnetic injection valve 1 that injects fuel with one revolution of the engine in the case of a 6-cylinder engine.
This frequency dividing circuit 3 is a 1/3 frequency dividing circuit for operating the electromagnetic injection valve 11 once in one revolution of the engine. Of course, this is true. 4 is an arithmetic circuit, and an intake air amount detection circuit 5
Then, by inputting a signal proportional to the intake air amount and a signal inversely proportional to the engine speed from the frequency dividing circuit 3, the intake air amount of the engine is divided by the engine speed, and the cycle is inversely proportional to the engine speed. It outputs a pulse signal T with a pulse time width t proportional to the amount of air sucked in in one stroke.

6 is a multiplication circuit that increases or calculates the pulse time width t of the pulse signal T outputted from the arithmetic circuit 4 according to various signals from the condition detection circuit 7 that detects engine cooling water temperature, intake air overflow, etc. Then, a pulse signal L having a pulse time width t2 is output.

Reference numeral 8 denotes a voltage correction circuit which inputs the pulse signal L from the multiplication circuit 6 and outputs a voltage correction pulse signal T3 having a time width for correcting changes in the fuel injection amount from the electromagnetic injection valve 11 depending on the applied voltage. It is something to do.

9 is an OR circuit which inputs the pulse signals T, , T2, L from the arithmetic circuit 4, the multiplication circuit 6, and the voltage correction circuit 8, and generates a pulse signal T with a pulse time width (t,+ra+ra). is supplied to the output circuit 1, and the electromagnetic injection valve 11 is opened during the time width of the pulse signal T (upper, 10 to 10 t3) to inject the optimum amount of fuel into the engine according to the operating state of the engine. supply.

The above configuration and operation are known as an electronically controlled fuel injection system. Reference numeral 12 is a reference pulse generation circuit using a retriggerable monostable multi-noise controller, and reference numeral 13 is a reference pulse generation circuit that uses the cycle of the pulse signal T synchronized with the engine rotation from the arithmetic circuit 4 and the reference pulse generation circuit 12. This is a comparison circuit that compares the pulse signal Tv with the time width tv.

The pulse time width tv of the reference pulse generation circuit 12 changes depending on the input signal, and a starter drive detector 14 for detecting the engine starting state is connected to the reference pulse generation circuit 12. 16 is a pulse signal T from the arithmetic circuit 4
, 17 is a monostable multipiper which generates a wide pulse signal Ts for a certain period of time in synchronization with the monostable multipipelator 16 and the pulse signal T from the arithmetic circuit 4. The comparison circuit 17 is a comparison circuit that compares the time width t, and is supported by a throttle detector 15 that detects the opening degree of the throttle valve.

The output signal of the comparison circuit 17 is sent to the reference pulse generation circuit 12 in order to change the time width W of the pulse signal Tv generated by the reference pulse generation circuit 12 according to the pulse signal T from the arithmetic circuit 4 or the opening degree of the throttle valve. It has been entered. The output of the comparison circuit 13 is input to the reference pulse generation circuit 12 in order to give hysteresis to the time width of the pulse signal Tv generated by the reference pulse generation circuits 1 to 2, and the hysteresis control circuit 18 for controlling the hysteresis width It is connected between the drive detector 14 and the reference pulse generation circuit 12. This configuration is for indirectly detecting the engine rotational speed from the operating state of the engine and providing hysteresis to the set value of the rotational speed to be detected, and its detailed configuration is shown in FIG. 2.

As shown in FIG. 2, a well-known D flip-flop is used as the comparator circuit 17, and a high level signal is input to its preset terminal P when the throttle valve function is less than the set opening.

The reference pulse generation circuit 12 includes a frequency divider 1201 and a resistor 120.
2 to 1213, 1226, 1227, transistor 12
14-1219, diode 1220, 1228, 12
29, capacitor 1221, comparator 1222, buffer 223, NAND gate 1224, inverter 12
25, and a low level signal is input to the buffer 223 during starter drive, that is, when starting the engine. A flip-flop is used as the comparison circuit 13, and the hysteresis control circuit 18 includes resistors 181,
182 and a transistor 183. Next, the operation of the configuration shown in FIG. 2 will be explained with reference to FIG. 3.

When the pulse signal T shown in FIG. 3A is input from the arithmetic circuit 4 to the frequency divider 1201, this pulse signal T becomes 1'2.
The pulse signal is turbidly converted into a pulse signal shown in FIG. 3B, and is input to the transistor 217.

It is clear that this pulse signal has a time width (period) that is inversely proportional to the engine speed. transistor 1217
is in an OFF state when this pulse signal is at a low level, and is in an ON state when it is at a high level. While the transistor 217 is in the OFF state, the capacitor 221 is charged, and its potential increases as the charging time increases, as shown in FIG. 3C. Comparator 1222 is capacitor 12
The charging potential of 21 and the constant potential Vs are compared, and a high level voltage is generated only when the charging potential is higher than the constant potential Vs. The output voltage level of this comparator 1222 is determined by the frequency divider 120.
Since the signal is inverted in transistor 216 in relation to the output level of 1, a pulse signal Tv is generated at the collector terminal of transistor 1216 as shown in FIG. 3D. This time width W is changed depending on the operating state of the engine. First, when the engine is started and the starter is being driven, the starter drive detector 14 sends a “0” signal (
low level signal) is input, and the inverter 225 outputs “1”.
“To generate a signal (high level signal), transistor 1
Since the transistor 219 is in the OFF state and the NAND gate 1224 also generates a "1" signal, the transistor 218 is also in the OFF state.
It becomes F state. Therefore, no current flows through the resistors 1211 and 1212, and the resistors 1211 and 1212 are not involved in charging the capacitor 221, and the reference pulse generating circuit is supplied with a pulse signal Tv having a time width tv, as shown in FIG. 3D.
occurs. The voltage across the capacitor 221 at this time is illustrated by the characteristic line C in FIG. 3C, and the time width tv,
depends on the characteristic line C. The time width tv, of the pulse signal Tv is equal to the first set rotation speed of the engine (for example, 40 pm).
) is set corresponding to the period of the pulse signal T. Next, when the starter is not driven, a "1" signal is input from the starter drive detector 14 to the reference pulse generation circuit 12, and the inverter 225 generates a "0" signal.
Transistor 219 is turned on, and resistor 1211
A current flows through. On the other hand, monostable multivibrator
6 generates a pulse signal Ts with a constant time width ts in synchronization with the pulse signal T, and the pulse signals Ts and T are input to the gate terminal D and clock terminal C of the D flip-flop of the comparator circuit 17, respectively. be done. Therefore, if the time width t of the pulse signal T, is 4 mm wider than the time width of the pulse signal Ts, the Q output and the Q output of the D flip-flop are "1" and "0", respectively. The throttle valve relation is transmitted from the throttle detector 15 to the preset terminal P of the flip-flop at the set opening (
For example, when a "1" signal indicating that the voltage is below 2.50) is input, the Q output and the Q output become "1" and ``0'', respectively, regardless of the data terminal ◯ input. D
Q of the flip-flop, the output “0” signal (indicating that the amount of fuel injection is small) and the “0” signal of the buffer gate 1223.
1” signal is input to the NAND gate 1224,
Since the NAND gate 1224 generates a "1" signal, the transistor 218 is turned off and no current flows through the resistor 1212. Therefore, the resistor 1211 is involved in charging the capacitor 221, and the reference pulse generating circuit 12 generates a pulse signal Tv having a constant time width W2 as shown in FIG. 3D. Capacitor 22 at this time
1 is shown by the characteristic line C2 in FIG. 3C, and the time width tvs depends on the characteristic line C2. The time width tv2 of the pulse signal Tv is set corresponding to the cycle of the pulse signal T at the second set engine speed (for example, 160 pm). Furthermore, when the starter is not driven, the Q output of the D flip-flop of the comparator 17 becomes a “1” signal (
Indicates that the fuel injection amount is large.

), both transistors 1219 and 1218 are in the ON state, so resistor 1211 and resistor 12
12 are involved in charging the capacitor 1221, and the voltage across the capacitor 1221 changes as shown by the characteristic line C3 in FIG. 3C. Therefore, the reference pulse generating circuit 12 generates a pulse signal Tv having a constant time width tv3 shown in FIG. 3D. This time width tv3 is the pulse signal T at the third engine speed (for example, 400 pm),
This is set in accordance with the period of . In other words, the reference pulse generation circuit 12 is activated.

The time width tv of the reference pulse Tv generated in response to input signals such as the throttle valve opening degree and the starter drive state is the time width tv corresponding to the first set rotation speed when the starter is driven, and the throttle valve function is Below the set value or pulse signal T,
When the time width is smaller than the wide set time width in the monostable multivibrator 16, the time width tv2 corresponds to the second set rotation speed, and furthermore, the time width tv2 corresponds to the second set rotation speed, and the time when the throttle valve opening is greater than the set value or the pulse signal T. When the width t is larger than the set time width ts, the time width tv3 corresponds to the third set rotation speed. Note that when the charging time of the capacitor 1221 of the reference pulse generation circuit 12 is short, that is, when the engine speed is high, the potential of the capacitor 1221 does not reach the set potential Vs, so the pulse signal Tv is
The output of 1 becomes an inverted pulse signal. Comparison circuit 13
Since the pulse signal Tv and the pulse signal shown in FIG. 3B are input to the data terminal D and clock terminal C of the D flip-flop, respectively, the D flip-flop receives the pulse signal Tv and the pulse signal shown in FIG. The signal level of the pulse signal Tv at is output to the Q terminal, and the opposite signal level is output to the Q terminal.

In other words, when the engine speed is higher than each speed setting value, the D flip-flop outputs "" to the Q terminal and the Q terminal, respectively.
1" signal and "0" signal, and conversely, when the engine speed is lower than each rotation speed setting value, the opposite signal is output. Therefore, the Q output signal or Q output signal of the ○ flip-flop of the comparator circuit 13 The engine rotation speed can be indirectly detected by using the engine speed, and by using the output signal for the electronically controlled fuel injection system shown in Figure 1, it is possible to detect the For example, as shown in FIG. 2, by inputting the Q output signal of the D flip-flop of the comparison circuit 13 and the Q output signal of the comparison circuit 15 to the NAND gate 201, The engine speed is the second set speed (
160 ratio pm) or more, the throttle valve opening becomes the set opening (2
．． 5o) “0” is output from the NAND gate 20 only when
The NAND gate 20' can thereby cut off the pulse signal T inputted to the output circuit 1 from the OR circuit 9 shown in FIG. Since the Q output signal of the D flip-flop is fed back to the transistor 1214 of the reference pulse generation circuit 12, the transistors 1214 and 121
5 is in the ON state when the engine speed is below each set speed, and resistor 1 209 is involved in charging the capacitor 1221.

However, when the engine speed exceeds each set speed, the Q output of the D flip-flop of the comparator circuit 13 is inverted from the "1" signal to the "0" signal as described above, so the transistors 1214 and 1215 are in the OFF state. Therefore, resistor 1 209 does not participate in charging capacitor 1 221. Therefore, characteristic line C in FIG. 3C, which shows the charging characteristics of capacitor 221, ? The slopes of C2 and C3 become smaller, and each set time width tv,, tv2, of the pulse signal Tv becomes smaller.
tv3 becomes larger. In other words, hysteresis is given to each time width W, , W2, and tv3 of the pulse signal Tv, and when the engine rotation speed exceeds one set rotation speed, the set rotation speed is set lower by the hysteresis. . As a result, when increasing or decreasing fuel beyond the set rotation speed, the increase or decrease can be done stably.
Engine hunting can be prevented.
．． Moreover, when a "0" signal is generated from the starter drive detector 14 indicating that the engine is starting,
Transistor 183 of hysteresis control circuit 18 is turned on
When the transistor 215 is in the ON state, that is, when the capacitor 221 is charged, part of the current flowing through the resistor 1209 flows through the resistor 182. However, when the engine speed becomes higher than the set speed, the resistor 1209 and the resistor 182 are connected to the capacitor 1221 as described above.
Therefore, the hysteresis of the time width tv of the pulse signal Tv becomes smaller than the hysteresis width of the first engine speed setting value. Therefore, the second
For example, set the hysteresis width of the set rotation speed (160 ratio pm) and the third set rotation speed (400 pm) to 40 pm.
Even if the rotation speed is set to about 10 pm, the hysteresis width of the first set rotation speed (40 pm) can be set to about 10 pm, for example. In this way, the lower limit of the number of set circuits is prevented from reaching a rotational speed that would cause the engine to stop. Assume that the fuel amount is increased while the engine is starting (the first set rotation speed is 40 ppm or less), and the fuel increase is stopped when the engine speed reaches the first set rotation speed of 40 ppm or higher.

In this case, the engine speed will decrease due to the fuel increase stop, but if the hysteresis width of the first set speed is set to a small value of about 10 pm, the engine speed will decrease to 30 pm.
When the amount of fuel decreases to a certain level, the amount of fuel will be increased again, and the engine will not stop. Further, depending on the engine, the hysteresis IJ system may not be necessary for the first set rotation speed, but in that case, the hysteresis of the first set rotation speed can be eliminated by shorting the resistor 182. As described above, in the present invention,
A pulse signal whose time width changes according to the driving state of the starter, the opening state of the engine throttle valve, etc. is generated, and the engine rotation speed is set according to the time width of this pulse signal. Since the engine speed is detected by comparing it with a pulse signal related to the speed, there is no need to increase the speed comparison means each time the set speed increases, and the engine speed can be detected with a simple configuration. This has the effect of not increasing the cost of the device, and since the hysteresis of the set rotation speed is changed depending on the starter drive state, throttle valve opening, etc., the reliability of the device's operation decreases. It has the excellent effect of not causing any

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is an electrical wiring diagram showing the detailed configuration of the main parts of FIG. 1, and FIG. 3 is a second diagram for explaining the operation of the present invention. It is a signal waveform diagram of each part inside. 12...Reference pulse generation circuit, 13...
・Comparison circuit, 14...Starter drive detector, 1
5... Throttle detector, 18... Hysteresis control circuit. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An electronically controlled fuel injection device that regulates the supply of fuel according to the operating state of the engine using a pulse signal synchronized with engine rotation, a starter drive detector that detects the starter drive state for starting the engine, and an engine throttle control system. A throttle opening detector that detects the opening of the valve, a reference pulse generation circuit that generates a pulse signal with a time width that changes depending on the output signals from both of these detectors, and a pulse signal of the electronically controlled fuel injection device. a comparison circuit that compares the cycle with the pulse signal time width of the reference pulse generation circuit; and a hysteresis that is applied to the pulse signal time width of the reference pulse generation circuit in accordance with the output signal of the comparison circuit to the throttle opening degree detector and A rotation speed for an electronically controlled fuel injection device, comprising a hysteresis control circuit that changes the rotation speed depending on the output signal of the starter drive detector, and detects the rotation speed of the engine based on the output signal of the comparison circuit. Detection device.