JPS6041222B2 - Correction air control device for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a correction air control device for an internal combustion engine,
In particular, the present invention relates to a device that uses a pulse motor to control the opening degree of a bypass valve provided in a correction air passage.

In this type of device, for example, an air-fuel ratio adjustment device, a detector for detecting the oxygen concentration in exhaust gas is installed in the exhaust pipe of the internal combustion engine, and the magnitude of the air-fuel ratio is determined based on the output signal from the detector. The internal combustion engine is further provided with an air-fuel ratio discrimination circuit, a pulse motor driven by the air-fuel ratio discrimination circuit, and a bypass valve connected to the pulse motor to control the passage area of the correction air passage of the carburetor. The air-fuel ratio of the mixture is controlled to be close to the stoichiometric air-fuel ratio.

However, in the conventional device described above, when the internal combustion engine is started cold (when the temperature of the internal combustion engine itself is low and the ignitability of the air-fuel mixture is poor), the device installed in the exhaust pipe detects the oxygen concentration, etc. in the exhaust gas. Since the detector cannot operate properly, control of the bypass valve provided in the correction air passage is temporarily stopped until the temperature of the internal combustion engine rises to a value at which the detector can operate properly. Therefore, when starting the internal combustion engine in a cold state, the position of the bypass valve should be such that the air-fuel ratio (slightly smaller than the stoichiometric air-fuel ratio) allows for a smooth start of the internal combustion engine. If an attempt is made to cold start the internal combustion engine with the bypass valve positioned at a position where a larger air-fuel ratio is achieved, the bypass valve will not be controlled when the internal combustion engine temperature reaches a certain value, and the above-mentioned start-up will occur. Therefore, even though a mixture with an air-fuel ratio smaller than the stoichiometric air-fuel ratio is required at the time of side-start, only an air-fuel mixture with an air-fuel ratio larger than the stoichiometric air-fuel ratio is supplied to the internal combustion engine. The disadvantage is that smooth starting is not possible. Therefore, in order to eliminate the above-mentioned drawbacks, the present invention provides an internal combustion engine equipped with a correction air passage.
A start detection means is provided to detect the start state of the internal combustion engine, and when it is determined that the engine is in the start state, the bypass valve of the correction air passage is driven by a pulse motor, and the opening degree of the bypass valve is controlled to a set value. It is an object of the present invention to provide a correction air control device for an internal combustion engine, which allows the internal combustion engine to be started smoothly and which allows easy control of the bypass valve by using a pulse motor.

The present invention will be described below with reference to embodiments shown in the drawings.

In this embodiment, the present invention is particularly applied to air-fuel ratio feedback control.

In FIG. 1, in the Kawama carburetor, the passage area of the main air intake passage 2 is controlled by the throttle valve Kamegawa, and the intake manifold 4 of the internal combustion engine 3 is made to communicate with the intake manifold 4 of the engine 3. Furthermore, the correction air passage 11 that communicates between the air cleaner 9 and the downstream side of the throttle valve 10, the bypass valve 12 that controls the passage area of the passage 11, and the relationship between the bypass valve 12 are controlled. The pulse mode 8 and the position where the bypass valve 12 can supply the air-fuel ratio required at the cold start of the internal combustion engine 3 (hereinafter referred to as the set position, and this set position will be explained assuming that the bypass valve is in the fully open position) 5 is an exhaust manifold through which the exhaust gas from the internal combustion engine 3 is discharged, and is provided with a setting position detector 13 for detecting whether the exhaust gas from the internal combustion engine 3 is in the Exhaust gas is discharged to the outside air.

7 is an air-fuel ratio detector using an oxygen concentration detector such as zirconium dioxide installed in the exhaust manifold 5, which generates an electromotive force according to the oxygen concentration in the exhaust gas, especially near the stoichiometric air-fuel ratio. It has step-like power characteristics.

Reference numeral 14 denotes a start detector that detects whether or not the internal combustion engine 3 is operating, and is composed of, for example, an alternator driven by the internal combustion engine 3.

Reference numeral 15 denotes an operating state detector for detecting the operating state of the internal combustion engine, for example, the temperature of the internal combustion engine.
0000) is detected.

Reference numeral 16 denotes a control means, which uses outputs from the air-fuel ratio detector 7, setting position detector 13, starting detector 14, and operating state detector 15 to control the oxygen concentration in the exhaust gas during normal operation of the internal combustion engine. The air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine is determined, and the darkness of the bypass valve 12 is controlled via the pulse motor 8 to adjust the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine to the stoichiometric air-fuel ratio. At the same time, when the internal combustion engine is started in a cold state, if the bypass valve 12 is not in the set position, the warning means alerts the driver of a malfunctioning start.

Next, details of the control circuit which is the control means 6 will be explained with reference to FIG.

Turtle 6-2 is a start detection circuit, which is composed of resistors 21, 22, 23, a capacitor 24, and a transistor 25.
The base of the transistor 25 is connected to the starting detector 14 via a resistor 2, and its collector is connected via a resistor 23 and a key switch 10G to a DC power supply IQI.

The start detector 14 and the start detection circuit 16-2 serve as start detection means, and until the rotational speed of the internal combustion engine reaches a certain value,
That is, since the transistor 25 is in a non-conducting state until the output voltage of the alternator that forms the start detector 14 reaches a certain value, a "1" level signal is generated at the output terminal 16-2a, and the internal combustion engine When the engine starts to start and its rotational speed exceeds a predetermined value, the transistor 25 becomes conductive and a "0" level signal is generated at the output terminal turtle 6-2a.
Reference numeral 3 denotes a set position detection circuit which is composed of resistors 31, 32, a transistor 33, and an inverter 34. The base of the transistor 33 is connected to the set position detector 13, and the collector is It is connected to a power source 101.

The set position detector 13 consists of a switch, and the switch is set so that the bypass valve 12 is at the set position, that is, the position where the air-fuel mixture can be supplied at the required air-fuel ratio (a value slightly smaller than the stoichiometric air-fuel ratio) at the time of cold start of the internal combustion engine. It opens only when the bypass valve 12 is set to the fully closed position. Therefore, the "1" level is generated at the output terminal 16-3a when the bypass valve 12 is located at a position other than the set position. 16
-7 is a discrimination means consisting of an AND gate, and output terminal 16 of each of the above-mentioned start detection circuit and set position detection circuit.
-2a, 16-3a, both output terminals 1
Only when both 6-2a and 16-3a are generating "1" level signals, that is, when the rotational speed of the internal combustion engine has not reached the predetermined value and the bypass valve is not at the set position, the AND gate is activated. Generates a “1” level signal at the output terminal.

16-8 is an alarm circuit, consisting of resistors 81, 82 and diode 8.
3, an alarm means 84 (for example, a lamp, a buzzer, etc.), and a transistor 85. The transistor 85
Its base is connected to the AND gate via a resistor 81, and its collector is connected to the power source 101 via a parallel circuit of a diode 83, a resistor 82, and an alarm means 84. Therefore, the transistor 85 becomes conductive when the discriminating means 16-7 generates a signal of the "1" level, and energizes the alarm means 84 to issue an alarm. Reference numeral 16-4 denotes an operating state detection circuit, which is composed of resistors 41, 42, 43, a capacitor 44, and a comparator 45. The inverting input terminal of the comparator 45 is connected to the operating state device 15, and its non-inverting input terminal is connected to the operating state detector 15. A set voltage obtained by dividing the fin pressure of the power source 101 is applied to the terminals by resistors 42 and 43.

The operating state detector 15 is composed of a thermistor or the like,
The higher the temperature of the internal combustion engine, the smaller the resistance value. Since the set voltage is set to a value corresponding to the temperature (approximately 4000 C) at which the air-fuel ratio detector 7 can properly operate, the resistance of the operating state detector 15 decreases. When the divided voltage of the power supply 101 obtained from the resistance value and the resistance value of the resistor 41 becomes equal to or less than the set voltage, a "1" level signal is generated at the output terminal 16-4a. 16
-5 is a resistor 51, a capacitor 54, a comparator 55, and a voltage dividing resistor 5 that inputs a set potential to the inverting input terminal of the comparator 55.
The non-inverting input terminal of the comparator 55 is connected to the air-fuel ratio detector 7 via a resistor 51.

As shown in FIG. 3, the electromotive force voltage characteristic of the air-fuel ratio detector 7 generates a large voltage when the detected air-fuel ratio is smaller than the stoichiometric air-fuel ratio (indicated by point a), and when it becomes larger than the stoichiometric air-fuel ratio, a step occurs. The voltage decreases in the same way as before, generating a small voltage. The voltage set by the voltage dividing resistors 52 and 53 is set slightly lower than the output voltage of the air/fuel detector near the stoichiometric air/fuel ratio. Therefore, when the air-fuel ratio is 4 and the output voltage is high, that is, when the air-fuel mixture is rich, a "1" level signal is generated at the output terminal 16-5a. 16-6 are NOR gates 61, 62, resistor 6
3. A pulse generator consisting of a capacitor 64.

The pulse signal of the pulse generator 16-6 is sent to the NOR gate 9.
3 and 94, respectively.

The output terminal 16-4a of the operating state detection circuit 6-4 is connected to one input terminal of the NAND gate 95 and the inverter 9.
0 to one input terminal of the NOR gate 91, and the output terminals 16-5a of the air-fuel ratio discrimination circuit 16-5 are connected to the other input terminals of the NAND gate 95 and the NOR gate 91, respectively. has been done. The output terminal of the NAND gate 95 is connected to the NOR gate 9.
The output terminal of the NOR gate 91 is connected to the other input terminal of the NOR gate 92, and the output state of the NOR gate 92 is connected to the other input terminal of the NOR gate 94. It is connected. When the output terminal 16-4a and the output terminal 16 5a are both generating signals of the "1" level, that is, the temperature of the internal combustion engine has reached a temperature at which the air-fuel ratio detector 7 can operate properly, and the When the air-fuel ratio discrimination circuit i6-5 detects that the air-fuel ratio of the air-fuel mixture is 4.0% higher than the stoichiometric air-fuel ratio (the air-fuel mixture is richer),
The NAND gate 95 applies a "0" level signal to the other input terminal of the NOR gate 93, and the NOR gate 93 receives a pulse generator 16- to which one input terminal is applied.
6 is applied to the first input terminal 0 of the shift register 96.

When a pulse signal is input to the first input terminal 0, the output terminals Q1, Q2, Q3, and Q4 are sequentially shifted, and the resistor 1
Transistors 106 to 109 connected to output terminals QI to Q4 through terminals 02 to 105 are sequentially controlled to be conductive, and field coils CI, C2, C3, and C4 of the pulse motor 8 are sequentially energized to generate pulses in the direction of the arrow in the figure. The motor is driven and the bypass valve 12 moves in the opening direction.

Further, a signal of "1" level is supplied to the output terminal 16-4a,
When a "0" level signal is generated at the output terminals 16-5a, that is, the temperature of the internal combustion engine has reached a temperature at which the air-fuel detector 7 can operate properly, and the air-fuel ratio is determined. When the circuit 16-5 detects that the air-fuel ratio of the air-fuel mixture is larger than the stoichiometric air-fuel ratio (the air-fuel mixture is lean), N
The OR gate 91 passes the “1” level signal to the NOR gate 9.
2 and the NOR gate 92
In order to apply a “0” level signal to the other input terminal of the NOR gate 94, the NOR gate 94 shifts the pulse signal from the pulse generator 16-6 applied to one input terminal. is applied to the second input terminal P of the register 96.

When a pulse signal is input to the second input terminal P, the output terminals Q4, Q3, Q2, and QI are sequentially shifted, and the pulse motor 8 rotates in the opposite direction to the arrow, thereby closing the bypass valve 12. drive Diode 110, 111, 11
2,113 is a diode for absorbing reverse starting power. 1
Reference numeral 6-9 denotes a starting position correcting means consisting of the NOR gate 92, one input terminal of which is connected to the discriminating means 16-7, and receives an input signal from the discriminating means 16-7 to correct the NOR gate 94. A “0” level signal is applied to the shift register 96, and a pulse signal is applied to the second input terminal P of the shift register 96.

More specifically, when the determining means 16-7 determines that the internal combustion engine is in the starting state and the bypass valve is not in the set position, and outputs a signal at the "1" level to its output terminal, the NOR gate is activated. The port 92 inputs the “0” level signal to the NOR
to the other input terminal of gate 94, and the NOR gate 9
4 applies the pulse signal from the pulse generator 16-6, which has arrived at one input terminal, to the second input terminal P of the shift register 96, and drives the bypass valve 12 in the opening direction. As a result, the bypass valve 12 is placed in the set position. Next, the operation of the above embodiment will be summarized.

Now, when starting the internal combustion engine 3, when the output voltage of the alternator, which is the starting detector 14, is not sufficient, that is, when the rotational speed of the internal combustion engine has not reached a predetermined value, the transistor 2
5 is not sufficient to control the conduction of the transistor 25, and the output terminal 16- of the start detection circuit 16-2
A "1" level signal is generated at 2a. At this time, when the bypass valve 12 is not at the set position and the switch of the set position detector 13 is open, a "1" level signal is also generated at the output terminal 16-3a of the set position detector 16-3. The output of the discrimination means 16-7 becomes "1" level, and the alarm means 84 is activated.
energizes the starting position correction means 1 to alert the driver that the cause of poor starting is the position of the bypass valve.
6-9 applies a pulse signal to the second input terminal P of the shift register 96, rotates the valve motor 8 in the direction opposite to the arrow, drives the bypass valve 12 in the direction of opening, and positions it directly at the set position. Make it a hawk.

When the internal combustion engine has finished starting and the output level of the alternator 14 has become sufficiently large, or when the bypass valve 12 has been driven to the set position, the determining means 16-7 outputs a "0" level signal. is generated, and the alarm by the alarm means 84 is stopped, and at the same time, the shift register 9 from the NOR gate 94
The input signal to 6 also disappears. Then, when the internal combustion engine starts to operate, the operating state detector 15 detects that the temperature of the internal combustion engine has not reached the appropriate operating temperature of the air-fuel ratio detector 7, and the output terminal 16-4a has a "0" level. The NANO gate 95 generates a ``0'' level signal and applies the ``0'' level signal to one input terminal, and applies a ``1'' level signal to the other input terminal of the NOR gate 93. ,
The NOR gate 93 transfers the pulse signal to the shift register 96.
is not applied to the first input terminal of.

Further, the "0" level signal at the output terminal 16-4a is inverted by the inverter 90, and the "1" level signal is applied to one input terminal of the NOR gate 91, so that the NOR gate 91 is "0" level. '' level signal is applied to the other input terminal of the NOR gate 92, which is the starting position correcting means 16-9.

At this time, as described above, since the discriminating means 16-7 is applying a "0" level signal to one input terminal of the NOR gate 92, the NOR gate 92 is applied to the other input terminal of the NOR gate 94. In order to apply a "1" level signal, the NOR gate 94 does not apply the pulse signal from the pulse generator 16-6 to the second input terminal P of the shift register 96, and the bypass valve 12 is in the set position. It remains held. Eventually, when the temperature of the internal combustion engine rises to a value that allows the air-fuel ratio detector 7 to operate properly, the operating state detection circuit 16-4 generates a "1" level signal at its output terminal 16-4a. Then, when the air-fuel ratio detector 7 detects that the air-fuel ratio of the mixture combined with the internal combustion engine is smaller than the stoichiometric air-fuel ratio, an output terminal 16-5a of the air-fuel ratio discrimination circuit 16-5 is output. A “1” level signal is generated and the NAN
The D gate 95 passes the “0” level signal to the NOR gate 93.
The NOR gate 93 applies a pulse signal to the first input terminal 0 of the shift register 96, driving the bypass valve 12 in the direction of Control to maintain the air-fuel ratio. In addition, when the bypass valve 12 opens to a certain extent and the air-fuel detector 7 detects that the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine is larger than the stoichiometric air-fuel ratio, that is, the air-fuel mixture concentration is low, the air-fuel ratio A “0” level signal is generated at the output terminal 16-5a of the discrimination circuit 16-5, and the “0” level signal is output to the NOR gate 9.
1 to the other input terminal.

An isoverter 9 is connected to one input terminal of the NOR gate 31.
Since a “0” level signal inverted from 01 is applied, the NOR gate 91 applies a “1” level signal to the other input terminal of the NOR gate 92. Therefore, the NOR gate 92 applies a "0" level signal to the other input terminal of the NOR gate 94, and the NOR gate 94
applies a pulse signal from the pulse generator 16-6 to the second input terminal P of the shift register 96, drives the pulse motor 8 in the direction opposite to the arrow, and moves the bypass valve 12 in the opening direction. , controls the air-fuel ratio of the air-fuel mixture to the stoichiometric air-fuel ratio. In the above embodiment, the set position of the bypass valve 12 was explained as a fully closed position, but it may be set at any other position. In that case, a position detection device such as a potentiometer to detect the position of the bypass valve may be used. Of course, it is only necessary to provide a control means for inputting control to the first or second input terminal of the shift register in accordance with the signals from the position detection means and the discrimination means.

Further, the above-mentioned discrimination means 16-7 is connected to the start detection means and the set position detection means, so that even when the internal combustion engine is not cold started (when the temperature of the internal combustion engine is sufficiently high),
Although the alarm means 84 issues an alarm and the bypass valve 12 is positioned at a set position, such control is often not necessary unless the cold start is being performed. The output of No. 4 may be input to the discrimination circuit 16-7 via an inverter as shown by the broken line in Fig. 2, so that an alarm may be issued only at the time of a slow start, or the bypass valve may be positioned at a set position. Of course.

As described above, in the present invention, in the correction air control device for an internal combustion engine in which the amount of air supplied to the internal combustion engine is corrected to increase or decrease by the correction air passage according to the engine condition, the correction air A bypass valve provided in the passage, a start detection means for detecting the starting state of the internal combustion engine, and a signal from the start detection means determine that the internal combustion engine is starting, and drive the pulse motor to bypass the engine. Starting function setting means for controlling the valve function to a set value The internal combustion engine can be started smoothly without starting problems, and the bypass valve function can be easily controlled by using a pulse motor. It has the excellent effect of being able to

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment of the bag counterfeit according to the present invention;
The figure is an electrical wiring diagram of the control circuit shown in Figure 1, and Figure 3 is the electrical wiring diagram of the control circuit shown in Figure 1.
It is a characteristic diagram of the illustrated air-fuel ratio detector. 3... Internal combustion engine, 8... Pulse motor, 1
DESCRIPTION OF SYMBOLS 1... Correction air passage, 12... Bypass valve, 13, 16-3... Back group localization layer detector and setting position detection circuit forming setting position detection means, 14 ,16
-2...Start detector and start detection circuit constituting start detection means, 16...Control circuit, 16-7,1
6-9...Discrimination means and starting position correction means forming the main part of the starting opening degree setting means. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] 1. In a correction air control device for an internal combustion engine, in which the amount of air supplied to the internal combustion engine is increased or decreased by a correction air passage according to the engine condition, a bypass valve provided in the correction air passage; a pulse motor that adjusts the opening degree of the bypass valve; a start detection means that detects a starting state of the internal combustion engine; and a signal from the start detection means that determines whether the internal combustion engine is starting and drives the pulse motor. and a starting opening setting means for controlling the opening of the bypass valve to a set value.