JPS59170757A - Air fuel ratio controller - Google Patents

Abstract

PURPOSE:To prevent the characteristic variation of a lean sensor by providing respectively the sensor detecting the theoretical air fuel ratio and the lean range, and stopping the current conducting the lean sensor when the theoretical air fuel ratio sensor detects the rich state. CONSTITUTION:A fixed voltage source 100 is connected to a platinum electrode 11 of the oxygen detecting cell side (lean range detecting cell side) through a switch element 110. An electrode 14 of the rich detecting cell side (theoretical air fuel ratio detecting cell side) is connected to the input terminal of a multiplexer element 130. If an MPU160 takes the driving information with the engine start, the MPU160 selects input ends C1, C2 of the element 130 through an output end O2 of an I/O port 150. If the driving state is in lean state, the control signal is outputted so that a switch element 110 is conducted from an output end O1 of the port 150 and if in rich state, in order to prevent the variation of the output characteristic of oxygen detecting cell, the element 110 is made to the nonconductive state, and the current conduction to oxygen detecting cell from the source 100 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Original Field of the Invention] The present invention relates to an air-fuel ratio control device for an internal combustion engine, and in particular to a control target air-fuel ratio for an internal combustion engine that is a stoichiometric air-fuel ratio and a stoichiometric air-fuel ratio.
The present invention also relates to an air-fuel ratio control device suitable for setting an arbitrary air-fuel ratio on the air-excess side, that is, on the lean side, and performing feedback control.

[Prior art]

The senna element that detects the oxygen concentration in the exhaust gas of your vehicle uses the mixing ratio of air and fuel (air-fuel ratio: A/F).
Lean sensors are known that detect the stoichiometric air ratio, and also detect the oxygen concentration in a region where the A/F candy is larger than the stoichiometric air ratio (lean mixture region: lean burn).

The former has an oxygen concentration cell configuration consisting of a Zr0z solid electrolyte and a platinum electrode, and the output of the sensor shows stepwise changes (depending on the oxygen partial pressure ratio between the electrodes) near the stoichiometric air-fuel ratio. Therefore, by detecting this output change, the stoichiometric air-fuel ratio can be detected. However, as described above, this sensor can only detect the stoichiometric air-fuel ratio, and is not suitable for detecting m degrees of oxygen in the IJ-ON region. Further, it has drawbacks such as being structurally complex and expensive.

Moreover, the latter Noriichi/Senna has been studied and many patent applications have been filed. Known examples include % patent publication No. 72286/1986, Japanese Patent Application Publication No. 166038/1982, and Japanese Patent Application Publication No. 55/1989, which utilize the diffusion rate-limiting effect of gas diffusion holes.
No. 166038, etc., and Japanese Patent Application Laid-open No. 166039/1983, which uses a porous member and uses a porous diffusion method, are known.

FIG. 1 shows an example of the lean sensing length of a sensor using diffusion control. In the same figure, Zirkoev 161
When a voltage is applied between the Nine Precepts electrodes 2°3 attached to both sides of the body electrolyte 1, (
Corresponding to the oxygen flux flowing in due to exhaust gas, a current flows, and this current is measured by an ammeter 6. This output nE current is proportional to the oxygen concentration in the exhaust gas. Therefore, it is only possible to detect the element concentration in the atmosphere. However, although these lean sensors can detect the V elemental intensity in the beam/area, they cannot detect the 3-dimensional air-fuel ratio. Is there a problem such as the sensitivity of the sensor characteristics changing or the hysteresis becoming large when the sensor is driven in a low air-fuel ratio region, that is, in a low range region, and then returns to the lean region?4. ``If the Lean sensor was used in a Lynchian attack, it is believed that this is due to electron transmission in the zirconia solid electrolyte and carbon deposition in the electrode section.

[Purpose of apology]

The purpose of the present invention was to detect the stoichiometric air-fuel ratio (excess air ratio λ-1) and the sail area (λ>1), and to detect the stoichiometric air-fuel ratio (excess air ratio λ-1) and the sail range (λ>1). In this region of λ≧1, feedback control can be performed at the air-fuel ratio 7, which is the most suitable from the requirements of economy and exhaust purification. The present invention provides a fuel ratio control device.

[Summary of the invention]

In order to achieve such an objective, the present invention provides fc for λ=1
The first cell J2 with 4 protrusions, λ〉1. By placing the 27th electrode for detecting λ on the same ZrO2 solid electrolyte and assembling 2m type electrode materials and taking advantage of these characteristics, λ = 1. The air-fuel ratio at λ〉l can be detected, and the characteristic change that occurs when the second cell is pivoted from lean to linker and from linker to lean is to be detected. When a cold condition is detected, the power supply to the second cell can be stopped.

Examples of the invention] Hereinafter, the present invention will be explained in detail using Examples.

First, before explaining embodiments of the invention, the principle of the sensor used in the present invention will be explained using FIGS. 2 and 3. In FIG. '
02 There is an internal body electrolyte 10, and platinum electrodes 11 and 12 are formed in one area of one surface of this solid electrolyte lO and in an area facing this area, respectively. A platinum electrode 13 is formed on the other area of the surface where the platinum electrode 13 is formed.
A gold electrode 14 is formed on the other surface opposite to the gold electrode 14 . An insulating film 15 is formed on the surface of the solid electrolyte 10 on which the platinum electrode 12 and the gold electrode 13 are formed, covering each of the electrodes, and a heater 16 is disposed on the upper surface of the insulating film 15. And the surface is processed like this! Further, a retention film 17 is formed and adhered to cover the entire surface. - Furthermore, an air-fuel ratio control circuit 18 is connected between the platinum electrodes 11 and 12, and an electromotive force detection circuit 19 is connected between the platinum electrode 13 and the gold electrode 14, respectively.

Senna constructed in this way is a solid electrolyte 1
The IJ-n area (λ
〉1) Oxygen detection cell for detecting the oxygen concentration, solid 1 is an electrolyte 10 and platinum 1f sandwiching it! , pole 13 and gold'
The detection cell for detecting λ-1 is constituted by the detector 14, and these are integrally formed.

Here, the operation of the oxygen detection cell will be explained. Assuming that the senna is exposed to exhaust gas, the poor fuel ratio control circuit 18 sets the platinum electrode 11 as an anode and the platinum electrode 1 as an anode.
A voltage is applied to 2 so that it becomes a cathode. Platinum electrode 12
The element in the near box is reduced and transferred to the platinum polarization 11 at the anode in the form of oxygen ions. Then, the oxygen ions are oxidized at the l+ portion and become oxygen molecules again and are released into the exhaust gas. As a result, the enzyme molecules in the vicinity of the platinum' electrode 12 decrease, so that the oxygen molecules in the exhaust gas pass through the insulating layer 15, the protective film 17, 17' and the Zr (hfi electrolyte 10). The pump's flow IP obtained from this method is expressed by the following equation.

Here, F is the Faraday footfall, D is the gas diffusion constant, it
is the gas constant, T is the absolute temperature of the electrolyte, S is the total cross-sectional area of the porous micropores, t is the length thereof, and PK is the oxygen partial pressure in the nodule gas.

Therefore, there is a proportional relationship between the Bongumi flow Ip detected by the dispersion cutting cell and the oxygen partial pressure in the exhaust gas, and the Bongumi flow Ip
p Lt) Oxygen partial pressure P in exhaust gas! can be easily detected.

Next, the operation of the rich detection cell will be explained. In this rich detection cell, an electromotive force e11 is generated by the oxygen partial pressure ratio at the electrode interface between the platinum electrode 13 and the gold electrode 14, as known from the Nernst equation.

If the oxygen partial pressure of Usukane Kamesen 13 is PA, then the starting force e8 is expressed by the 11th order equation.

Now, when operating in a state where there is little oxygen in the exhaust gas, that is, in a rich state (oxygen still exists in this case), carbon monoxide and oxygen in the gas are converted to CO2 by the catalytic action of the platinum electrode 13. and a platinum electrode 13 and a solid electrolyte 1
At the interface with 0, the oxygen partial pressure PA becomes smaller. −
Unlike platinum electrodes, gold electrodes do not have a catalytic effect, so their partial pressure is almost equal to the oxygen partial pressure in the exhaust gas.

Due to the partial pressure ratio between the oxygen component EEP gold electrode 1
The fourth side i/C has a high potential. Next, υi・) When operating in a state where there is a lot of oxygen in the gas, that is, in a lean state,
The CO concentration in the exhaust gas is lower than 02 degrees.

Therefore, the electromotive force el is small, about 0.1 volt.

Therefore, by monitoring the electric power e generated in both chikusa of the rich detection cell and detecting the sudden change point of e♂ with respect to the air-fuel ratio, the stoichiometric air-fuel ratio is controlled, and thereby the rich region can be easily detected.

The relationship between the air-fuel ratio A/F, the bong E flow Ip, and the electromotive force e8 in the above-mentioned section is shown in Figure 3. Here, the error rate of arousal elements in exhaust gas in a lean state is proportional to the air-fuel ratio or excess air ratio λ.

Next, the flowchart of FIG. 4 will be used to explain how the air-fuel ratio control circuit section 18 uses a microcomputer (hereinafter abbreviated as "microcomputer").

After the initialization, the microcomputer that starts when the engine starts takes in operating information and determines whether the current operating state is rich or on.
Take in Tonka eII. ΔfPU (Micro Pro
In cessor (Jnit), f of imported e3
It is determined whether or not it is richer than l&.

If lean is determined in M P
, to detect the degree of acidity in the pleasant gas in order to compare r1? Electrify the outgoing cell. As a result, the oxygen detection cell obtains a Bongumi-style JP suitable for brewing@degrees, which is then imported into the gold microcomputer.

The MPU detects the concentration of iodine in the exhaust gas from the Bongumi flow IP taken in by the MPU, and detects the fuel ratio in the current operating state from the proportional relationship between the oxygen error and the air-fuel ratio [2, this calculation] It is determined whether the fuel ratio matches the control target air-fuel ratio or not, and if it matches, (operation 1 blind alarm detection is performed. If it does not match, fi;!f nF(i [-1 The magnitude relationship of the n-shaped fuel ratio with respect to the Yanagi air-fuel ratio is determined, and the fuel injection amount is corrected so that if #f is a dog, the fuel injection amount is increased, and if it is small, the injection amount is decreased. Then, the air-fuel ratio is calculated again by taking in the Bong-gumi flow IP, and the comparison with the control target air-fuel ratio is repeated to match the correction of the multi-fuel injection amount. Feedback control of operating conditions at the optimum air-fuel ratio is possible, and can be performed at any point.

When rich is determined by the MPU, when the oxygen detection cell is energized in the rich region as described above, the output characteristics change due to electron conduction in the cell, etc. Therefore, in order to prevent this, the power supply to the oxygen detection cell is stopped or its level is reduced based on the rich determination. Then, the output of the detection end of the rich detection cell is monitored so as to perform feedback control at the stoichiometric air-fuel ratio at the current limit tL.

By repeating this detailed ll1U control, feedback control at the stoichiometric air-fuel ratio and optimal air-fuel ratio feedback in the lean region9
:1' can be easily controlled, and deterioration of the lean sensor during delivery can be prevented.

Next, an embodiment of the air-fuel ratio control device according to the present invention is shown in FIG. A constant voltage power supply 100 is provided, and this power is supplied via a switch element 110 to a platinum electrode 11 on the oxygen detection cell side of the senna. Further, the platinum electrode 12 on the oxygen delivery cell side is shielded via a resistor 120. This resistor 120 serves as an Ipp output resistor for detecting the flow Ip of the valve '1. Also, the input terminal C! of the multiplexer element 130 with 14 gold electrodes on the Lynch hand output cell side! The other input terminal C2 is connected to the platinum % electrode 12 on the oxygen detection side. Note that the platinum electrode 13 on the rich) protruding cell side is grounded. The output of the multiplexer element 130 is input to an analog 7-digital converter (hereinafter referred to as A/D converter) 140, and the output of this A/D converter 140 is input to an input/output port (hereinafter referred to as 110 port) 150. It is now entered. This I10 boat 150 is connected to the MPU via an input/output bus, and also has R, A M (Random
Access Memory) l 7 Q, and ROM (ReadQn'ly MernOrY
) = 180, respectively through the input and output lotuses I10
Beau) 150. MPU160 and I/Q horde 150
, MPU160. The data is read directly into the RAM 170. In addition, I10 baud) to 150.

In addition, the 1h signal that controls the ON and OFF states of the hIJ switch hexagon 110 is configured to output 2, and a fuel correction output terminal 190 that performs the FP3 positive operation is provided. ing.

The outline of the operation of this air-fuel ratio 1b1 control device is shown in 9 of the flowchart shown in FIG.
When the operating information is imported, the output terminal Ox of the I10 boat 150
commands to select input C1 of multiplexer element 130 via . The output terminal C1 is connected to the terminal of the 4iit pole 1-4, and the electromotive force between the gold electrode 14 and the white canister 13,
Let e 3 be detectable 'i1. The electromotive force e generated by the CI is converted into a digital signal by the A/D converter 140 and sent from the input terminal 1 of the I10 boat 150 to the MPU.
It falls within 160. This is done to determine whether the current operating state is rich or lean, and if the determination result is lean, a control signal is output from the output terminal 01 of the I10 boat 150 so that the switch electronic 110 becomes conductive.

When the switch element 110 becomes conductive, the enemy force detection cell's platinum'
The output abrasive pressure (approximately 1 volt) of the tail voltage source 100 is applied to the polarity reversal 11 and the platinum reversal 12. As a result, there is a partial pressure (
A pump current Ip which is 1" lower than that of
/ Pu'ton style I? is detected at the voltage level Vrp by the voltage drop of the Ip detection resistor 120TUL. This voltage Vr
p is A/D from the multi-grain length element 1300 Å force end C2
It is taken into the MPU 160 via the converter 140 and the beka m11 of the I10 boat 150.

At this time, a command is sent from m1pu16o to select input terminal C2 of multiplexer 150 via output mOg of I10 boat 150.

The MPU 160 determines the target air-fuel ratio to be controlled in the region based on the operation information received earlier.

In addition, the N1PU 160 detects the oxygen concentration in the exhaust gas from the voltage Vsp corresponding to the flow Ip of the bonder '4, and further calculates the air-fuel ratio from the calculated air-fuel ratio and the target air-fuel ratio. The correction for increasing or decreasing the injection amount is output from the fuel correction output end 190 via the output end 03 of the I10 boat 150.

The signal at the input terminal C1 of the multiplexer element 130 is sent to the MPU
If it is determined that the oxygen detection cell 160 is rich, it is necessary to stop the flow of 1ifL to the cell or reduce its level in order to prevent a change in the output characteristics of the oxygen detection cell. therefore,
From the MPU 160, the output terminal of I10 baud) 150 O! A signal is sent to make the switch element 110 non-conductive, the switch element 110 is opened, and the current supply from the constant voltage source 100 to the oxygen detection cell is stopped. After that, perform the conventional feedback control process for the stoichiometric nitrous fuel ratio noise F, and go to step 4 again. The PU 160 takes in the electromotive force e5 of the rich output cell and determines the operating state. Therefore, until the electromotive force es of the lynch detection cell reaches the output level in the lean state, the processing at the lynch shown in L is repeated.

Note that determining whether the operating state is lynch or lynch is an important role in preventing changes in the characteristics of the oxygen detection cell. Although not described in the above embodiment, it is necessary to treat this as an interrupt signal having the highest priority.

Figure 445 is a diagram showing another embodiment of the air-fuel specific gravity control device according to Fukou Akira. Z is a porous sintered body
There is a r 02 solid electrolyte 200, and this solid electrolyte 2
00 has platinum electrodes 201 and 202 shaped like JJv. Furthermore, a porous or dense sintered ZROZ solid electrolyte 203 is laminated on the surface of the homogeneous electrolyte 1A200 on which the platinum electrode 202 is provided, and the side of this solid electrolyte x203 opposite to the platinum 4-pole 202 side is laminated. A gold electrode 204 is provided on the surface.

In the cell configured in this way, first, the 'source terminal 2
05, and this power supply terminal 205 is connected to the platinum electrode 201 via the 11.pn type transistor 206 and the switching element 110.

The platinum electrode 202 is connected to the resistor 2 for detecting the pump current Ip.
It is grounded through the terminal 09 and is drawn out as an output terminal 229.

The output of the gold electrode 204 is connected to one terminal of the differential amplifier 207, and one terminal 210 is connected to the terminal 1. The target voltage value can be input. The output of the differential amplifier 207 is connected to the n
It is designed to be input to the pace of the pn type transistor 206. There is a comparison m211 whose ten terminals are connected to the platinum electrode 201 and one terminal to the gold electrode 2o4, and its output is input to the base of the transistor 216 via the diode 213 and the resistor 215. It is now possible to do so. There is also a comparator 212, whose -;i4 terminal is wired to the platinum electrode 204, and its terminal is connected to the reference '1'a voltage, and its output is connected to the mediode 2j. 4, the voltage is input to the transistor 216 via the resistor 215 (front 46npn2VJ). The npn type transistor 216
is such that power is supplied to its collector terminal, and the emitter terminal is connected to the ground via a resistor 217 and taken out as an output terminal 220, and
+iiJ output pair, the switching element 1' 10 coo N, OFF by the output from t220)
j is supposed to be in charge.

Air-fuel ratio control @j device e7 configured in this way:! ~
For operation in a lean region without trenches, a solid electrolyte 200 and a platinum electrode 2 are connected to the pump cell consisting of white electrodes 201 and 202.
When a voltage is applied such that 01 is the eyelid, a pump current It is obtained that is proportional to the exhaust gas concentration. this? It is detected by the voltage drop across the IP detection resistor 209. 1, solidity
The electromotive force of equation (2) above is generated between the sensor cell platinum 1i1, etc. 202 and the metal electrode 204, which is composed of a metal electrode 203, a platinum electrode 202, and a gold electrode F204, depending on the electromotive force ratio! A
I live here.

- crotch (also known as Z r Oz solid K M 5
The impedance of Q shows all the changes in thickness l depending on the temperature,
The impedance of the low temperature axis increases.

For this reason, if the excitation voltage E' applied to the pump cell is fixed at a constant value (approximately 1 volt), the heel skin becomes extremely low temperature, and the ohmic loss Ui pressure also increases due to impedance, so it cannot operate at low temperatures. It disappears. As a means to eliminate this problem, the excitation voltage of the pump cell is controlled by feedback so that the electromotive force es of the sensor cell becomes 1 volt. Because of this, the oxygen concentration in the vicinity of the platinum electrode 202 is controlled to be optically low, so that a pump current of optical fraction yf+ii that is sensitive to the oxygen concentration can be obtained even on the low temperature side. The constant (surface control) of this electromotive force ei is performed by the differential amplifier 207, the plus input terminal 210 receives the fljiJ target voltage II port, and the minus input section receives the platinum ``torme'' h 204
A force C8 is applied to the voltage at the input terminal, that is, the voltage V'. The difference@amplifier 207 detects the deviation of these two wrestlers, and the 4-power resistor 20
The excitation voltage E of the bomb cell is varied by a transistor 206 connected to 8, and feedback control is performed so that the polarization becomes zero.

Next, the operation of Lynch Kenda will be explained.

The rich detection means uses the excitation voltage E of the Pong cell and the frosting force es of the sensor cell. By controlling the above-mentioned electromotive force eg of the sensor cell to a constant value, the excitation voltage E of the bow cell can be adjusted to the ohmic overload voltage 1il'4, which is ↓ between the control voltage value and the impedance #Qi of the bow cell. Becomes a glassed confession. Therefore, in the lean region, a current (2) proportional to the oxygen I#summer is obtained, so the magnitude relationship between the power IJ paper electromotive force E and the electromotive force C8 becomes E) e s.

On the other hand, in the rich region, the oxygen acidity of Pongcell's platinum polarity reversal 201 field [nj becomes sufficiently low due to the catalytic action. In addition, since the Senna cell uses a gold electrode 204, there is no catalytic action, and the interface between the platinum electrode 202 and the gold electrode 204
Ultra-short forces e and f are generated depending on the oxygen concentration difference with the interface. Therefore, the magnitude relationship between the excitation voltage E and the excitation force eε is E-<, e g .

Therefore, judgment of the magnitude relationship between E and e5 & more theoretical quantity, 7
<The ratio value and the lean region can be easily detected, and it is possible to prevent changes in the characteristics of the bong I-flow IF.

To do this, the platinum electrode 20 input to the comparison 5211
The magnitude relationship between the excitation voltage E of 1 and the force eg of the gold electrode 204 is determined. The output signal of the comparator 211 is "Ilight" when the lean region E > e a, and the output signal is "Ilight" when the lean region E > e a;
(When es is selected, the level becomes "LOW".

Diodes 213, 214, resistor 2], 5.2I7,
The transistor 216 constitutes an OR circuit, and the comparator 21
In the lean region where the output of 1 is at the "l (high") level, the control end of the switch element 110 is set to ")iii".
'' level is applied, and the switch 8 element 110 becomes conductive.

Conversely, in the rich state, the output of the comparator 211 is 'I,o
w'' level, and the switch element 110 becomes non-conductive.

However, in the upper circle method, when the state changes from rich to lean, the switch element 110 does not become conductive, making it impossible to detect oxygen concentration in the lean region. As a means of solving this problem, a comparator 212 is used to set the electromotive force ea at the negative input terminal and the comparison potential Vth, which is half of the electromotive force e that changes when the sensor cell is in a rich or lean state, at the positive input terminal. input. Due to this, the comparator 212
The output level is e g (V t ) in a rich state, -T LOW level in a lean state,
h becomes ``)(igh''), and the OR° circuit can be controlled using this signal.

That is, the rich and lean regions are determined by OR, and the output terminal 22 connected to the emitter terminal of the transistor 216 of the circuit.
0's Isho No. V Bell Vok is detected, and when vO is "High", it is a clear signal, and when it is "LOW", it is a rich region.

Although not shown, the bo/b city 7 flow which is proportional to fbe4 chastity is determined from its output end 219, ``rich, lee/'' is manually inputted to the output end 200L re-microcomputer, and the stoichiometric air-fuel ratio and 4M 7I depending on the optimum air and fuel ratio in the lean tμ range
i control is performed.

FIG. 47 shows another embodiment 1 of the air-fuel ratio control device according to Akira Honmoto et al.
+11 is a block diagram showing a modification of the embodiment shown in FIG. 6. The same reference numerals as in FIG. 6 indicate the same materials.

In FIG. 7, the sensor section is a zirconia solid acid electrolyte 2
00, 300, platinum electrodes 201, 202, 301, and gold electrodes 302. The determination of richness and 'J -7% range is performed using the gold electric box 302 in contact with the waste, the platinum electrode 202 as a reference, and the comparator 212.

Unlike platinum electrodes, gold electrodes do not have catalytic activity, so gold electrodes 3
The interface between 02 and the zirconia solid electrolyte 300 has an oxygen concentration of 4 degrees in the exhaust gas. On the other hand, the oxygen concentration near the platinum electrode 202 is too low for catalytic action. Therefore, in a rich case, the oxygen concentration ratio is large and the electromotive force eg of the gold electrode 302 is large (approximately 1 volt), whereas in a lean case, e becomes almost zero. Input this electromotive force ei to the negative end of the comparator 212, and input the shoulder voltage level to the positive end of the comparator 218. Therefore, the output of the comparator 212 is LOW when it is rich, and HIGH when it is lean.
level, and by determining the signal at the output terminal 220 from this level, the stoichiometric air-fuel ratio can be detected. Furthermore, upon detecting a rich state, the switch element 110 is brought into a non-conducting state,
Stops energizing the pump cell in rich conditions to prevent characteristic changes. On the other hand, in the lean region operation, the transistor 206
, amplifier 207, Shirokane VIL2ox, 202. :3o
x, M weight solute 2 CI O.

3L) 0, as explained in FIG.
It is output from 9.

Note that the signals from the output terminals 219 and 220 can be processed by a control unit such as a T icon, and optimal feedback control can be performed.

[The young fruits of invention]

As is clear from the above description, 1. According to the air-fuel ratio control device according to the present invention, the stoichiometric air-fuel ratio (excess air ratio λ-1
) and the lean region (λ〉1), and in this region of λ, 1, the most suitable control target is the nitrogen fuel ratio at an arbitrary point commensurate with the operating condition based on the requirements for fuel consumption and exhaust purification. can be set and feedback control can be performed using this air-fuel ratio.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional sensor element for detecting the oxygen concentration in gas, and FIG. 2 shows an embodiment of the air-fuel ratio control device according to the present invention.]4 Figure 3 is a graph showing the characteristics of the sensor, and Figure 4 is an example of the operation of the air-fuel ratio control device according to the invention. The flowchart shown in FIG. /(Air-fuel ratio control device 1
FIG. 4, FIG. 6, and FIG. 7 are block diagrams showing other embodiments of the air-fuel ratio control device according to the present invention, respectively. 1 (3,200...Solid 'sedate, 11,12゜13
゜2ul, 202'/platinum electrode, 14,204...
Gold electrode, 1υ0...constant voltage source, 130...-Multig V-shaft, 140...A/D converter, 150...Person output boat, 160...M: PU1207, 211, 2
12... Differential amplifier, 2o6.216... npn type transistor. Agent Accountant Tatsuyuki Unuma $ 1 Ward 77' $2 Hard 1゜〆lδ $3 Hard 7Lζl-人-I□-人n/ Complete stock north A/F 4th-eye 5th eye l, fθ

Claims (1)

[Claims] 1. A first cell for detecting the stoichiometric air-fuel ratio and a second cell for detecting a lean region are integrated into a solid electrolyte,
An air-fuel ratio control device characterized by comprising means for stopping energization of a second cell when a rich state is detected by the @1 cell.