JPS5925112B2 - Correction air control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a correction air control device in an internal combustion engine intake system.

Conventionally, for example, this type of correction air control device has an air-fuel ratio determination circuit that determines the magnitude of the air-fuel ratio based on an output signal from a detector that detects the oxygen concentration in exhaust gas as one of the engine operating parameters. , further comprising a pulse motor driven by the air-fuel ratio discrimination circuit, and a bypass valve connected to the pulse motor as a valve means for controlling the passage area of the correction air passage of the carburetor, and supplying the air to the internal combustion engine. There is a method that controls the air-fuel ratio of the air-fuel mixture to be the stoichiometric air-fuel ratio.

In this type of device, when starting the internal combustion engine cold (when the humidity of the internal combustion engine itself is low and the ignitability of the air-fuel mixture is poor), the temperature of the internal combustion engine is determined by considering the startability of the engine and characteristics during warm-up operation. It is necessary to temporarily stop the control of the bypass valve installed in the compensation air passage until the temperature rises and stable operation is possible. Furthermore, when the internal combustion engine is started cold, the position of the bypass valve, that is, the amount of compensation air, is It is necessary to control the air-fuel ratio and intake air amount to an appropriate amount so that the internal combustion engine can be started smoothly.

The present invention has been made in view of the above points, and it improves the startability of the engine by setting and controlling the correction air amount, that is, the valve opening, which can provide the air-fuel ratio or intake air amount required at the time of starting the engine. The purpose is to make it better.

An embodiment in which the present invention is applied to a device for controlling the air-fuel ratio of an internal combustion engine using correction air will be described below.

In FIG. 1, 1 is a carburetor, and a throttle valve 10
By controlling the passage area of the main mixture passage 2, the air cleaner 9 and the intake manifold 4 of the internal combustion engine 3 are communicated with each other.

The carburetor 1 further includes a correction air passage 11 communicating between the air cleaner 9 and the downstream side of the throttle pulse 10.
a bypass valve 12 as a valve means for controlling the passage area of the passage 110; a driving means 8 comprising, for example, a pulse motor, for controlling the opening degree of the bypass valve 12; As a valve opening detection means for detecting whether the bypass valve is at a position (hereinafter referred to as a set position, and this set position will be explained assuming that the bypass valve is in a fully closed position) that can supply the air-fuel ratio required at the time of a state start. It is equipped with a set position detector 13-1.

Reference numeral 5 denotes an exhaust manifold through which exhaust gas from the internal combustion engine 3 is discharged, and the exhaust gas is discharged to the outside air via an exhaust purification device such as a catalytic converter 6.

Reference numeral 1 denotes an air-fuel ratio detector using an oxygen concentration detector such as zirconium dioxide installed in the exhaust manifold 5 to detect air-fuel ratio information as an engine operating parameter, and detects an electromotive force according to the oxygen concentration in the exhaust gas. It has a stepped output voltage characteristic, especially near the stoichiometric air-fuel ratio.

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, and in particular the activation temperature (approximately 400°C) at which the air-fuel ratio detector γ provided in the exhaust manifold 5 can perform proper operation. Detect whether .

Reference numeral 14 denotes a control means, which uses the outputs from the air-fuel ratio detector 1, the set position detector 13-1, and the operating state detector 15 to
During normal operation of the internal combustion engine 3, the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 3 is determined from the oxygen concentration in the exhaust gas.
Controlling the opening degree of the bypass valve 12 via the driving means 8,
Controls the air-fuel ratio of the air-fuel mixture to the stoichiometric air-fuel ratio.

Of course, when performing this control, the control means 14 receives power from the on-vehicle DC power supply 1γ via the power supply circuit 16.

The power supply circuit 16 supplies power to the control means 14 at the same time as the key switch 16-1 (shown in FIG. 2) is turned on, and when the key switch 16-1 is opened, the control means At the same time as power is supplied to the control means 14, a position correction signal is applied to the control means 14.

Next, details of the control means 14 and the power supply circuit 16 will be explained based on FIG. 2.

14-4 is an operating state detection circuit, which includes resistors 4L42, 43.
capacitor.

44, and a comparator 45, the inverting input terminal of the comparator 450 is connected to the operating state detector 15, and the non-inverting input terminal receives a set voltage obtained by dividing the voltage of the power supply 1γ by a resistor 42.43. is being applied.

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, and the set voltage is set to a value corresponding to the temperature (approximately 400°C) at which the air-fuel ratio detector γ can properly operate. increases, and the voltage-dividing type of power supply 1γ obtained by the resistance value of the operating state detector 15 and the resistance value of the resistor 41 is generated.
When the voltage falls below the set voltage, the operating state detection circuit 14-
A signal of 1° level is generated at the output terminal 14-4a of 4.

14-5 is an air-fuel ratio discrimination circuit composed of a resistor 51, a comparator 54, and a voltage dividing resistor 52.53 that inputs a set voltage to the inverting input terminal of the comparator 540, and the non-inverting input terminal of the comparator 54 is It is connected to the air-fuel ratio detector γ via a resistor 51.

As shown in Fig. 3, the electromotive force voltage characteristics of the air-fuel ratio detector γ are such that when the air-fuel ratio detected is smaller than the stoichiometric air-fuel ratio (point a), a large voltage is generated, and when the detected air-fuel ratio is smaller than the stoichiometric air-fuel ratio (point a), it generates a large voltage. When the voltage decreases in steps, a small voltage is generated.

The voltage set by the voltage dividing resistors 52 and 53 is set to be slightly higher than the output voltage of the air-fuel ratio detector near the stoichiometric air-fuel ratio.

Therefore, when the air-fuel ratio of the air-fuel mixture detected by the air-fuel ratio detector γ is small and its output voltage is high, that is, when the air-fuel mixture is rich, the output terminal 14-5a of the air-fuel ratio discrimination circuit 14-5 is
1 It level signal is generated.

14-6 is a NOR gate 6L62. A pulse generator consisting of a 63° resistor and a capacitor 64, the pulse signal of the pulse generator 14-6 is applied to one input terminal of a NAND gate 92, and the other input terminal of the NAND gate 92 is It is connected to the state detection circuit 14-4.

When a signal of 1+1+Level is generated at the output terminal 14-4a of the operating state detection circuit 14-4, that is, when the temperature of the internal combustion engine reaches a temperature at which the air-fuel ratio detector γ can perform proper operation. , the NAND gate 92 converts the pulse signal from the pulse generator 14-6 into a NOR gate 93,
94, respectively, to one input terminal.

The output terminal 14-5a of the air-fuel ratio discrimination circuit 14-5 is
One input terminal of NAND gate 99 and inverter 9
5 to one input terminal of the NOR gate 91-.

An output terminal 16- of a first relay 16-2, which will be described later, is connected to the other input terminal of the NOR gate 91 via an input 101.
The other input terminal of the NAND gate 99 is connected to the output terminal 16-2a via an inverter 90 and a line 101.

When a key switch 16-1, which will be described later, is turned on, a 0 level signal is generated at the output terminal 16-2a, and the EI OII level signal is applied to the inverter 9.
0 and the signal at the tl I 11 level is applied to the other input terminals of the IO gates 99, so that the output terminal 14-5a of the air-fuel ratio discrimination circuit 14-5
Only when a signal of level 1 is being generated at 1, a signal of level 0 is applied to the other input terminal of the NOR gate 93, so that the signal of level 0 is applied to one input terminal of the NOR gate 93 A pulse signal from the pulse generator 14-6 is applied to the first input terminal O of the shift register 96.

Further, the output terminal 145 of the air/fuel ratio discrimination circuit 14-5
When aK“0” level signal is generated and is 2, the corresponding “O”
Since the level signal is inverted by the inverter 95 and the signal of level "1" is applied to one input terminal of the NOR gate 91, the NOR gate 91 is inverted to the other input terminal of the NOR gate 94. A pulse signal from the pulse generator 14-6 is applied to one input terminal of the NOR gate 94 through an inverter 89 to one input terminal of the NOR gate 94. is applied to the input terminal of

Other input terminals of the NOR gate 91 are set position detectors 13-1. Resistance 13-2. It is connected via an inverter 88 to set position detection means consisting of a capacitor 13-3.

The set position detector 13-1 is closed only when the bypass valve 12 is in the fully closed state, which is the set position, and is open otherwise.

Therefore, when the bypass valve 12 is at the set position (・, the NOR gate 9γ receives a “0” level signal at the other input terminals (・), so if a pulse signal arrives at one input terminal, The pulse signal is applied to the second input terminal P of the shift register 96.

The power supply circuit 16 includes a key switch 16-1 consisting of a two-circuit switch, a first relay 16-2, and a delay circuit 16-.
3 and a second relay 16-4.

The first relay 16-2 is connected to the key switch 16-2.
1, a first fixed contact 2a connected to a second contact 1b,
A movable piece 2e connected to the fixed contact 2a, a second . Third fixed contacts 2b, 2c, and the key switch 16-1
It consists of a relay coil 2d connected to a fourth contact 1d, and a resistor 2fs2g connected to a fixed contact 2c. When the key switch 16-1 is turned on as shown by the solid line in the figure, the relay coil 2d is energized. Then, the movable piece 2e is connected to the first and second fixed contacts 2a and 2b as shown by solid lines.

Therefore, when this key 1 isochi 16-1 is turned on, as described above, the output terminal 16 of the first relay 16-2
-2a generates a "0" level signal.

The delay circuit 16-3 is composed of a resistor 3ay3b, a capacitor 3c, and a transistor 3d, and the base of the transistor 3d is connected to the second fixed contact 2b via a resistor 3a.

Therefore, when the movable piece 2e is connected to the second fixed contact 2b, the transistor 3d is controlled to be conductive, and at the same time, the capacitor 3c is also charged.

The second relay 16-4 includes a relay coil 4b connected between the second contact 1b and the collector/emitter circuit of the transistor 3d, and a normally open contact 4a that is driven and closed by the relay coil 4b. It consists of

98 is a switching circuit connected to the shift register 96, which connects resistors R1, R2, R3, R4, transistors T1 t T2 , T3 t T4 to back electromotive force absorbing diodes D1 , D2 . The field coil C1 of the pulse motor 8 is connected to the collector-emitter circuit of each of the transistors TI-T4.

C2, C3, and C4 are connected in series.

Next, the operation of the apparatus of the present invention having the above structure will be described.

When the key switch 16-1 is turned on, the first contact 1a and the third contact 1c are connected, and via the cable 100,
The power supply circuit 16 energizes the control means 14 .

At the same time, the relay coil 2d is energized, the movable piece 2e is coupled with the second fixed contact 2b, the transistor 3d is made conductive, the relay coil 4b is energized, and the normally open contact 4a is closed, so the normally open contact Power is also supplied to the cable 100 via the cable 4a.

Then, the temperature of the internal combustion engine 3 is the activation temperature of the air-fuel ratio detector 1 (
400°C), the operating state detection circuit 1
4-4 generates a "°0" level signal at its output terminal 14-4a, and the NAND gate 92
The pulse signal from 4-6 is converted to the NOR game) 93.94
not applied.

Therefore, the shift register 96 has the first . Second input terminal O
, P does not receive a pulse signal, so the bypass valve 12 is not driven in either the opening or closing direction.

Next, the humidity of the internal combustion engine increases and the operating state detection circuit 14
-4 generates a "1" level signal at its output terminal 14-4a, a pulse signal from the pulse generator 14-6 is applied to one input terminal of each of the NOR gates 93 and 94.

When the air-fuel ratio discrimination circuit 14-5 receives a signal from the air-fuel ratio detector γ and detects that the air-fuel mixture is rich, that is, the air-fuel ratio is smaller than the stoichiometric air-fuel ratio, the output terminal 14-5a is Generates a “1” level signal, and generates a “1” level signal.
” level signal is applied to one input terminal of the NAND gate 99.

Further, as for other input terminals, the signal is generated at the output terminal 16-2a.

0" level signal is inverted by the inverter 90.
Since the signal of I11 level is applied, the NAND
The gate 99 is connected to the other input terminal of the NOR gate 93.
0'' level signal is applied, and the NOR gate 93
applies the pulse signal applied to one of its input terminals to the first input terminal O of the shift register 96.

When a pulse signal is input to the first input terminal O, the output terminals Q1, Q2, Q3 and Q4 of the shift register 96 are sequentially shifted, the transistors T1 to T4 of the switching circuit 98 are sequentially controlled to conduct, and the pulse motor 8 The field coils 01 to C4 are sequentially energized, and the pulse motor 8 rotates in the direction of the arrow in the figure, driving the bypass valve 12 in the direction of opening.

By driving the bypass valve 12 in the opening direction,
The amount of air supplied from the correction air passage 11 is increased, the air-fuel ratio is increased, and the air-fuel ratio is controlled to become the stoichiometric air-fuel ratio.

Conversely, when the air-fuel ratio determination circuit 14-5 receives a signal from the air-fuel ratio detector 1 and determines that the air-fuel mixture is lean, that is, that the air-fuel ratio of the air-fuel mixture is greater than the stoichiometric air-fuel ratio. , generates a "0" level signal at its output terminal 14-5a, and the "0" level signal is sent to the inverter 9.
5, and a signal at the °°1" level is applied to one input terminal of the NOR gate 91.

At this time, the NOR gate 91 applies a "0" level signal to the other input terminal of the NOR gate 94, and the pulse generator 1 applied to one input terminal of the NOR gate 94
The pulse signal from 4-6 is applied to one input terminal of NOR gate 9T via inverter 89.

When a signal of 0" level arrives at the other input terminal of the NOR game) 97, the bypass valve 12 is not at the set position (fully closed position) and the set position detector 13-1 is open. At this time, the NOR gate 91 applies the pulse signal applied to one of its input terminals to the second input terminal P of the shift register 96.

When a pulse signal is input to the second input terminal P, its output terminals Q4, Q3, Q2, and Qt are sequentially shifted, and the transistors T4, T3, T2, and T1 are sequentially shifted.
are sequentially controlled to conduct, and the field coil C4 of the pulse motor 8
, C3, C2, and C1 are sequentially energized, the pulse motor 8 rotates in the direction of the arrow in the figure, and the bypass valve 12 is driven in the closing direction.

By driving the bypass valve 12 in the closing direction, the amount of air supplied from the correction air passage 11 is reduced,
Reduce the air-fuel ratio and control it to the stoichiometric air-fuel ratio.

Further, when a “1” level signal arrives at the other input terminal of the NOR gate 91, that is, when the bypass valve is at the set position (fully closed position), the NOR gate 91 transfers the pulse signal to the shift register 96. Even though the bypass valve 12 is in the fully closed position,
The pulse motor 8 further moves 1 in the direction of closing the bypass valve 12.
Since it is not driven, problems such as damage to the bypass valve 12 and burnout of the pulse motor 8 do not occur.

Next, the operation when stopping the internal combustion engine will be explained.

When the key switch 16-1 is opened as shown by the broken line in the figure, the contacts 1a and 1c are disconnected.

In addition, since the relay coil 2d is also cut off, the movable piece 2e connects the first and third fixed contacts 2a and 2 as shown by the broken line.
c and the output terminal 16-2 of the first relay 16-2.
A "1" level signal which becomes a position correction signal is generated at a.

Transistor 3d of delay circuit 16-3 is key switch 1
The conductive state is maintained by discharging the capacitor 3c for a certain period of time from the time when the capacitor 6-1 is opened.

Therefore, since the cable 100 is connected to the mold source 1γ while the normally open contact 4a is in the closed state, power is supplied to the control means 14 for a certain period of time from the time when the key switch 16-1 is opened, that is, when the engine is stopped. .

As described above, since a ``1'' level signal is generated at the output terminal 16-2a, the NOR gate 91 to which the ``1'' level signal is applied to the other input terminal is a NOR gate.
A signal of "0" level is applied to the other input terminal of gate 94.

Further, immediately after the key switch 16-1 is opened, the temperature of the internal combustion engine is almost the same as the temperature when the internal combustion engine is operating, so the operating state detection circuit 1 f4 is connected to its output terminal 14.
-4a is generating a ``1'' level signal, and the NAN
D gate 92 continues to apply the pulse signal from pulse generator 14-6 to NOR gates 93 and 94.

Therefore, the NOR gate 94 applies a pulse signal to one input terminal of the NOR gate 9γ, and if the bypass valve 12 is not in the fully closed position and a “0” level signal is applied to the other input terminals, the shift register A pulse signal is applied to the second input terminal P of 96 to drive the bypass valve 12 in the closing direction as described above, and the bypass valve 12 is finally located at the set position (fully closed position).

Furthermore, even if the air-fuel ratio discrimination circuit 14-5 generates a signal of "'1" level at its output terminal 14-5a when the key switch 16-1 is opened, the other input terminals of the NAND gate 99 are “1’ generated at output terminal 16-2a
“0” which is inverted by the inverter 90
Since the level signal is applied, the NOR gate 93
A “1” level signal is applied to the other input terminal of the
No pulse signal is applied to the first input terminal 0 of the shift register 96.

Therefore, when the internal combustion engine is stopped, the bypass valve 12 is always located at the set position, so that the next time the internal combustion engine is started, the air-fuel mixture with the air-fuel ratio required at a cold start is always supplied. This makes it possible to smoothly start the internal combustion engine.

Next, FIG. 4 showing a second embodiment of the present invention will be described.

FIG. 4 shows details of the power supply circuit 16, 16-1
, 16-4 shows a key switch and a relay as in the first embodiment, and 16-5 sends a signal of "°0" level to the cable 101 when the key switch 16-1 is turned on, and the key switch 16 -1 is opened, cable 10
1 to the inverter 90.

This is a signal circuit that supplies a “1” level signal, and is a 16-
6 is a relay coil 4 connected to the set position detection means 13 to close the normally open contact 4a until the set position detector is closed.
This is a delay circuit that energizes b.

The signal circuit is composed of resistors 5a, 5b, 5d, and a transistor 5c, and the resistors 5a, 5b are connected to the fourth contact 1d and control the conduction of the transistor 5c as long as the key switch 16-1 is turned on. There is.

Since the cable 101 is connected to the collector of the transistor 5c, the cable 101 generates a "0" level signal while the transistor 5c is conductive.

The delay circuit 16-6 includes a transistor 6a connected in series to the relay coil 4b, and a transistor 6b in the preceding stage thereof.

6c, and resistors 6d, 6e, and 6f, and the base of the transistor 6c is connected to the set position detection means.

Next, the operation of the second embodiment will be explained.

When the key switch 16-1 is turned on, the contact 1a is turned on.

1c and cable 100, power is supplied to control circuit 14.

At this time, if the bypass valve 12 is not in the set position and the set position detector 13-1 is open, the transistor 6c is conductive and the transistor 6a is also conductive, so the relay coil 4
b is energized, the normally open contact 4a is closed, and the normally open contact 4a is closed.
Power is also supplied to the control means 14 from the cable 100 from a.

and key switch 1 to stop the operation of the internal combustion engine.
When 6-1 is opened, the contacts 1a and 10 are disconnected, so power is no longer supplied through the contacts 1a and Ic.

When this key switch 16-1 is opened, the bypass valve 12
When the switch is not at the fully closed position, which is the set position, the set position detector 13-1 is open and the transistors 6c and 6a continue to conduct, so the normally open contact 4a is kept closed. Power is supplied to the control means 14 via the normally open contact 4a and the cable 100.

Further, when the key inch 16-1 is opened, the transistor 5c is controlled to be non-conductive, and the NOR gate 91 is applied with a position correction signal of 1" level.

Therefore, as explained in the first embodiment, the bypass valve is moved in the closing direction by the position correction signal.

Then, the bypass valve 12 is brought to its set position, which is the fully closed position.
When the set position detector 13-1 is located, the set position detector 13-1 is closed and the transistor 6C26a is controlled to be non-conductive, so the normally open contact 4a is opened and the control means 1 is connected via the cable 100.
The power supply to 4 is stopped.

Therefore, since the bypass valve 12 is always located at the set position when the engine is stopped, the next time the internal combustion engine is started, it can always supply the internal combustion engine with the air-fuel mixture at the air-fuel ratio required during a cold start.

In addition, in the above-mentioned embodiment, the set position of the bypass valve was explained as the fully closed position, but it may be set at any other position. What is necessary is to provide a position detecting means, and a means for inputting and controlling a pulse signal to the first or second input terminal of the shift register according to the signal from the position detecting means and the position correction signal. Of course.

As described above, in the present invention, the amount of correction air for adjusting the air-fuel ratio or mixture amount required at the time of engine startup, that is, the opening degree of the valve means, is set to the opening degree corresponding to the time of engine startup. This has the excellent effect of improving engine startability.

In particular, in the first aspect of the invention, by setting the optimum valve opening for the next start when the engine is stopped, the engine can be immediately and satisfactorily started the next time the engine is started.

In addition, the second invention is equipped with a valve opening detection means and controls the opening of the valve means in response to a signal from the valve opening detection means, so that the opening can be controlled to the optimum opening with high accuracy, resulting in even better starting performance. If you can measure sexual improvement, it will have a great effect.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the configuration of an embodiment of the present invention, FIG. 2 is an electrical wiring diagram of the control means and power supply circuit shown in FIG. 1, and FIG.
1 is a characteristic diagram of the air-fuel ratio detector shown in FIG. 1, and FIG. 4 is an electrical wiring diagram of a power supply circuit in another embodiment of the device of the present invention. 3... Internal combustion engine, 1... Air-fuel ratio detector, 8... Driving means, 11... Air passage for correction, 12... Bypass valve, 13-1... Setting position detector, 14... Control means.

Claims (1)

[Claims] 1. A correction air passage provided in an intake system of an internal combustion engine;
a valve means provided in the correction air passage for controlling the amount of correction air; and a drive means for adjusting the opening degree of the valve means;
an air-fuel ratio detector, and after activation of the air-fuel ratio detector, the device drives the driving means based on the air-fuel ratio detection signal to control the opening degree of the valve means to control the air-fuel ratio. and a control means for controlling the opening degree of the valve means when the engine is stopped to a set opening degree corresponding to when the engine is started. 2. A correction air passage provided in the intake system of an internal combustion engine;
a valve means provided in the correction air passage for controlling the amount of correction air; and a drive means for adjusting the opening degree of the valve means;
an air-fuel ratio detector, and after the air-fuel ratio detector is activated, the device drives the driving means based on a signal from the air-fuel ratio detector to control the opening degree of the valve means to control the air-fuel ratio. A valve opening detection means for detecting the opening of the valve means is provided, and when the engine is stopped, the opening of the valve means is set to a set opening corresponding to the output of the valve opening detection means when the engine is started. 1. A correction air control device comprising: control means for controlling.