JPH0117101B2 - - Google Patents
Info
- Publication number
- JPH0117101B2 JPH0117101B2 JP55107528A JP10752880A JPH0117101B2 JP H0117101 B2 JPH0117101 B2 JP H0117101B2 JP 55107528 A JP55107528 A JP 55107528A JP 10752880 A JP10752880 A JP 10752880A JP H0117101 B2 JPH0117101 B2 JP H0117101B2
- Authority
- JP
- Japan
- Prior art keywords
- oxygen sensor
- voltage
- comparator
- output
- capacitor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000001301 oxygen Substances 0.000 claims description 31
- 229910052760 oxygen Inorganic materials 0.000 claims description 31
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 30
- 239000000446 fuel Substances 0.000 claims description 12
- 239000003990 capacitor Substances 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 7
- 239000007789 gas Substances 0.000 claims description 6
- 238000001514 detection method Methods 0.000 claims description 4
- 230000007423 decrease Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 2
- 150000002926 oxygen Chemical class 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/406—Cells and probes with solid electrolytes
- G01N27/4065—Circuit arrangements specially adapted therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Molecular Biology (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】
この発明は内燃機関の排気ガス流中の酸素を検
出する酸素センサの出力検出回路に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an output detection circuit for an oxygen sensor that detects oxygen in an exhaust gas stream of an internal combustion engine.
内燃機関に対して吸入される空気・燃料混合気
の混合比を予め定められた値（理論空燃比）に制
御するために排気ガス流中に酸素センサを配設
し、この酸素センサ出力を比較電圧に対する大小
判別によりスイツチング出力に変換し、このスイ
ツチング出力を積分処理してこの積分出力により
混合比を閉ループ補正する閉ループ制御系が実現
されている。 In order to control the mixture ratio of the air/fuel mixture taken into the internal combustion engine to a predetermined value (stoichiometric air-fuel ratio), an oxygen sensor is installed in the exhaust gas flow, and the output of this oxygen sensor is compared. A closed-loop control system is realized in which the switching output is converted by determining the magnitude of the voltage, the switching output is subjected to integral processing, and the mixture ratio is corrected in a closed loop using the integral output.
第１図、第２図はこの閉ループ制御系に使用さ
れる酸素センサの出力をレベル判別検出する回路
とその動作説明図を示すものであり、酸素センサ
１はエンジンの排気ガス流中に配設され、その作
動温度以上においては第２図Ａで示す如く理論空
燃比（空気過剰率λ＝１）を境にして最大・最小
終値間でレベル反転する出力電圧を発生する。 Figures 1 and 2 show a circuit for level discrimination and detection of the output of the oxygen sensor used in this closed loop control system and an explanatory diagram of its operation. Oxygen sensor 1 is installed in the exhaust gas flow of the engine. As shown in FIG. 2A, above the operating temperature, an output voltage is generated whose level is inverted between the maximum and minimum end values with the stoichiometric air-fuel ratio (excess air ratio λ=1) as the boundary.
この酸素センサ１の出力電圧（Vs）は比較器
２において所定の比較電圧（Vref）と大小比較
されスイツチング（Ｈ・Ｌレベル）出力に変換さ
れる。ここで酸素センサ１は作動温度以上の高温
時には第２図Ａで示す如くλ＝１で急峻にレベル
変化する出力を発生するため比較電圧（Vref）
と比較したとき比較器２の反転動作点はλ＝１に
対応するが、排気ガス温度の低下により酸素セン
サ１の内部抵抗γが増大して比較器２の入力バイ
アス電流（iB）による電圧降下（iB・γ）が増大
し、しかも酸素センサ１自身の起電力も低下する
ことから酸素センサ１の出力電圧（Vs）は第２
図Ｂに示す如き特性を呈する。このため比較器２
の比較電圧（Vref）は酸素センサ１の内部抵抗
γの変化とその起電力の変化とを共に考慮して設
定する必要があることからその設定は極めて困難
であり、加えて、酸素センサ１の出力電圧特性は
低温になるほど、λ＝１付近における電圧レベル
変化（傾き）はλが１以上の方向（リーン側）へ
延びて緩かになる傾向があることから、例えば機
関アイドル時等の排気ガス温度が低下した時の混
合比制御において制御中心がリーンサイドにシフ
トして希薄混合気によつてエンジンに回転ムラが
生じる等の問題があつた。 The output voltage (Vs) of the oxygen sensor 1 is compared in magnitude with a predetermined comparison voltage (Vref) in a comparator 2 and converted into a switching (H/L level) output. Here, since the oxygen sensor 1 generates an output whose level changes sharply at λ=1 as shown in FIG. 2A when the temperature is higher than the operating temperature, the comparison voltage (Vref)
The inversion operating point of comparator 2 corresponds to λ = 1 when compared with Since the drop (i B・γ) increases and the electromotive force of the oxygen sensor 1 itself also decreases, the output voltage (Vs) of the oxygen sensor 1 becomes
It exhibits characteristics as shown in Figure B. Therefore, comparator 2
It is extremely difficult to set the comparison voltage (Vref) of the oxygen sensor 1 because it needs to take into account both the change in the internal resistance γ of the oxygen sensor 1 and the change in its electromotive force. As for the output voltage characteristics, as the temperature decreases, the voltage level change (slope) near λ = 1 tends to extend in the direction where λ is 1 or more (lean side) and become more gradual. When the gas temperature drops, the center of control shifts to the lean side in the mixture ratio control, causing problems such as uneven rotation of the engine due to the lean mixture.
この発明は上記実情に対処すべくなされたもの
であつて、酸素センサ出力と比較電圧とを比較す
る比較器の比較電圧を酸素センサ出力に対応して
制御することにより酸素センサの温度に対する影
響を改善して所定の空燃比付近を検出し得、厳密
な比較電圧管理を不要とし得る酸素センサ出力検
出回路を提供しようとするものである。 The present invention was made in order to cope with the above-mentioned situation, and the influence on the temperature of the oxygen sensor is reduced by controlling the comparison voltage of a comparator that compares the oxygen sensor output and the comparison voltage in accordance with the oxygen sensor output. It is an object of the present invention to provide an oxygen sensor output detection circuit that can be improved to detect the vicinity of a predetermined air-fuel ratio and that can eliminate the need for strict comparison voltage management.
以下第３図第４図について説明する。先ず第３
図において、３は抵抗４，５と共に電圧増幅器を
構成し酸素センサ１の出力電圧（Vs）を電圧増
幅する演算増幅器でその出力電圧（Vs1）は比較
器２の一方の入力端子に与えられている。 3 and 4 will be explained below. First, the third
In the figure, 3 constitutes a voltage amplifier with resistors 4 and 5, and is an operational amplifier that amplifies the output voltage (Vs) of oxygen sensor 1, and its output voltage (Vs 1 ) is applied to one input terminal of comparator 2. ing.
６，７は互いに直列接続されて上記出力電圧
（Vs1）が印加されるダイオードとコンデンサで
あり、該コンデンサ７は上記出力電圧（Vs1）に
よりその最大終値からダイオード６の電圧降下
（VD）だけ低い電圧値に充電されその値を記憶保
持する。８は放電抵抗であり上記コンデンサ７の
放電時間が、上述の閉ループ空燃比制御の際の酸
素センサ１のリーン・リツチサイクル周期（0.1
〜2sec）より充分長くかつ酸素センサ１の温度変
化（数10sec〜数分）には追従できる程度（数
10sec）に選定されており、上記コンデンサ７の
電圧が比較器２の比較電圧（Vref）となつてい
る。 6 and 7 are a diode and a capacitor that are connected in series with each other to which the above output voltage (Vs 1 ) is applied, and the capacitor 7 has a voltage drop (V D ) is charged to a lower voltage value and stores and retains that value. 8 is a discharge resistor, and the discharge time of the capacitor 7 is the lean/rich cycle period (0.1
~2 seconds) and long enough to follow the temperature change (several tens of seconds to several minutes) of oxygen sensor 1 (several tens of seconds to several minutes).
10 seconds), and the voltage of the capacitor 7 is the comparison voltage (Vref) of the comparator 2.
次にこの様に構成された実施例の動作について
説明する。 Next, the operation of the embodiment configured in this manner will be explained.
酸素センサ１の出力電圧（Vs）は演算増幅器
３抵抗４，５から成る増幅器によつて電圧増幅さ
れこの増幅出力電圧（Vs1）は比較器２の一方の
入力端子に与えられる。ここで上記増幅出力電圧
（Vs1）は酸素センサ１の温度が所定値以上の状
態では第４図A1で示す如くλ＝１を境として最
大・最小終値間を急峻にレベル変化するが、その
温度低下により、第４図Ｂで示す如く酸素センサ
１の起電力が低下し内部抵抗が増大することか
ら、最大終値が低下し最小終値が上昇して最大・
最小終値間のレベル差が縮小し、かつ両終値間の
レベル変化が緩かになる。一方、この増幅出力電
圧（Vs1）はダイオード６を介してコンデンサ７
を充電し、上述の如く比較的長い時定数をもつて
抵抗８へ放電することから、コンデンサ７の端子
電圧（Vref）は、λ＜｜のときに増幅出力電圧
（Vs1）が最大値にあるときダイオード６の一定
電圧降下（VD）だけ（Vs1）から減算された電圧
（Vs1−VD）に充電され、λ＞｜のとき最小終値
にあるときはその電圧（Vs1−VD）を所定時間は
記憶保持するため、上述の閉ループ空燃比制御に
おいては、実質的に上記比較電圧（Vs1−VD）を
与えることになる。このため酸素センサ１の温度
が変化して増幅出力電圧（Vs1）が変動しても、
比較器２の比較電圧（Vref）は第４図点線で示
す如く、常に増幅出力電圧（Vs1）の最大終値か
らダイオード電圧（VD）だけ小さい値に追従し
従来装置の如き厳密な比較電圧の管理が不要で比
較器２の反転動作点は常にλ＝１に近いところと
なり、例えば機関アイドル時等の酸素センサ１の
温度が低いところでも良好な空燃比の制御が可能
となる。 The output voltage (Vs) of the oxygen sensor 1 is amplified by an amplifier consisting of an operational amplifier 3 and resistors 4 and 5, and this amplified output voltage (Vs 1 ) is applied to one input terminal of the comparator 2. Here, when the temperature of the oxygen sensor 1 is above a predetermined value, the amplified output voltage (Vs 1 ) sharply changes in level between the maximum and minimum final values with λ=1 as the boundary, as shown in FIG. 4 A 1 . As the temperature decreases, the electromotive force of the oxygen sensor 1 decreases and the internal resistance increases as shown in FIG. 4B, so the maximum final value decreases and the minimum final value increases, resulting in
The level difference between the minimum closing prices is reduced, and the level change between the two closing prices becomes gradual. On the other hand, this amplified output voltage (Vs 1 ) is passed through diode 6 to capacitor 7.
Since the terminal voltage (Vref) of the capacitor 7 is charged and discharged to the resistor 8 with a relatively long time constant as described above, the amplified output voltage (Vs 1 ) reaches its maximum value when λ<| At a certain time, it is charged to a voltage (Vs 1 - V D ) that is subtracted from (Vs 1 ) by a constant voltage drop (V D ) of diode 6, and when it is at the minimum final value when λ>|, that voltage (Vs 1 - V D ) is stored and held for a predetermined period of time, so in the closed loop air-fuel ratio control described above, the comparison voltage (Vs 1 −V D ) is substantially applied. Therefore, even if the temperature of oxygen sensor 1 changes and the amplified output voltage (Vs 1 ) fluctuates,
As shown by the dotted line in Figure 4, the comparison voltage (Vref) of comparator 2 always follows a value smaller than the maximum final value of the amplified output voltage (Vs 1 ) by the diode voltage (V D ), and is not as accurate as the comparison voltage of the conventional device. The inversion operating point of the comparator 2 is always close to λ=1, and the air-fuel ratio can be controlled favorably even when the temperature of the oxygen sensor 1 is low, such as when the engine is idling.
以上の如くこの発明は排気ガス流中に設けられ
エンジンの吸入混合気の理論空燃比を境として最
大・最小終値間でレベル変化する出力電圧を発生
する酸素センサと、この酸素センサ出力に対応す
る出力と比較信号とを入力として大小比較する比
較器とを備えるものにあつて、比較器の比較信号
レベルを比較入力レベルの一方の終値から所定値
だけずれた値に制御する手段を設けたので、酸素
センサの温度変動にかかわらず、厳密な比較信号
レベルの管理設定が不要となり、かつ比較器の反
転動作を理論空燃比に近いところで行なわせるこ
とが可能となり良好な空燃比制御を可能にし得る
ものである。 As described above, the present invention includes an oxygen sensor that is installed in the exhaust gas flow and generates an output voltage that changes in level between the maximum and minimum end values with the stoichiometric air-fuel ratio of the engine intake air-fuel mixture as the boundary, and an oxygen sensor that corresponds to the output of the oxygen sensor. In a device that is equipped with a comparator that receives an output and a comparison signal as input and compares their magnitudes, it is provided with a means for controlling the comparison signal level of the comparator to a value that deviates from the final value of one of the comparison input levels by a predetermined value. Regardless of the temperature fluctuations of the oxygen sensor, strict control of the comparison signal level is not required, and the reversal operation of the comparator can be performed close to the stoichiometric air-fuel ratio, making it possible to achieve good air-fuel ratio control. It is something.
又、上記制御される比較レベルは、定電圧降下
素子と、これと直列なコンデンサと抵抗の並列回
路とによつて発生させるようにしたので、極めて
簡単安価に構成できるものである。 Further, since the controlled comparison level is generated by a constant voltage drop element and a parallel circuit of a capacitor and a resistor connected in series with the constant voltage drop element, it can be constructed extremely simply and at low cost.
第１図は従来回路を示す電気回路図、第２図は
第１図の動作説明用特性図、第３図はこの発明の
一実施例を示す電気回路図、第４図は第３図の動
作説明用特性図である。
図中１は酸素センサ、２は比較器、３は演算増
幅器、４，５，８は抵抗、６はダイオード、７は
コンデンサである。
FIG. 1 is an electric circuit diagram showing a conventional circuit, FIG. 2 is a characteristic diagram for explaining the operation of FIG. 1, FIG. 3 is an electric circuit diagram showing an embodiment of the present invention, and FIG. It is a characteristic diagram for explaining operation. In the figure, 1 is an oxygen sensor, 2 is a comparator, 3 is an operational amplifier, 4, 5, and 8 are resistors, 6 is a diode, and 7 is a capacitor.
Claims (1)
燃料混合気の空燃比が所定値を境として最大・最
小終値間でレベル変化する出力を発生する酸素セ
ンサ、この酸素センサの出力に対応した入力を第
１の入力端子に受ける比較器、この比較器の第１
の入力端子に与えられる入力電圧を定電圧降下素
子を介して受ける互いに並列なコンデンサと抵
抗、及び上記コンデンサと抵抗の並列回路の両端
電圧を上記比較器の第２の入力端子に与える接続
手段を備えて成る酸素センサ出力検出回路。1 Installed in the exhaust gas stream of the engine to
An oxygen sensor that generates an output in which the air-fuel ratio of the fuel mixture changes in level between a maximum and minimum final value with a predetermined value as the boundary, a comparator that receives an input corresponding to the output of the oxygen sensor at a first input terminal, and this comparison. first vessel
A capacitor and a resistor connected in parallel to each other receive an input voltage applied to an input terminal of the comparator via a constant voltage drop element, and a connection means for supplying a voltage across the parallel circuit of the capacitor and resistor to a second input terminal of the comparator. Oxygen sensor output detection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10752880A JPS5733346A (en) | 1980-08-05 | 1980-08-05 | Detecting circuit for output of oxygen sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10752880A JPS5733346A (en) | 1980-08-05 | 1980-08-05 | Detecting circuit for output of oxygen sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5733346A JPS5733346A (en) | 1982-02-23 |
| JPH0117101B2 true JPH0117101B2 (en) | 1989-03-29 |
Family
ID=14461470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10752880A Granted JPS5733346A (en) | 1980-08-05 | 1980-08-05 | Detecting circuit for output of oxygen sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5733346A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54155889A (en) * | 1978-05-30 | 1979-12-08 | Nippon Soken | Air fuel ratio detector |
-
1980
- 1980-08-05 JP JP10752880A patent/JPS5733346A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54155889A (en) * | 1978-05-30 | 1979-12-08 | Nippon Soken | Air fuel ratio detector |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5733346A (en) | 1982-02-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4804454A (en) | Oxygen concentration sensing apparatus | |
| US4167925A (en) | Closed loop system equipped with a device for producing a reference signal in accordance with the output signal of a gas sensor for internal combustion engine | |
| US4112893A (en) | Air/fuel ratio control system for internal combustion engine having high input impedance circuit | |
| JPS5820379B2 (en) | Air fuel ratio control device | |
| JPS59163556A (en) | Oxygen concentration detecting apparatus | |
| US4131089A (en) | Electronic closed loop air-fuel ratio control system | |
| JPS6022293B2 (en) | Method for analyzing and controlling the composition of a fuel mixture supplied to an internal combustion engine | |
| US4393841A (en) | Device for regulating the fuel-air ratio in internal combustion engines | |
| JPS584177B2 (en) | Feedback air-fuel ratio control device for electronically controlled injection engines | |
| US5307625A (en) | Method and arrangement for monitoring a lambda probe in an internal combustion engine | |
| US4178884A (en) | Method and system to control the mixture air-to-fuel ratio | |
| JPS5834654B2 (en) | Method and device for controlling and adjusting fuel-air component ratio of working mixture of internal combustion engine | |
| US4171690A (en) | Emission control system for internal combustion engines utilizing balance differential amplifier stage | |
| JPS6118664B2 (en) | ||
| US4187806A (en) | Fuel-air mixture control apparatus | |
| US4519237A (en) | Oxygen-sensing system | |
| US4338900A (en) | Fuel metering apparatus in an internal combustion engine | |
| US4314537A (en) | Fuel feedback control system for internal combustion engine | |
| US5671721A (en) | Apparatus for determining the condition of an air-fuel ratio sensor | |
| JPS6033988B2 (en) | Air fuel ratio control device | |
| JPH0672867B2 (en) | Oxygen concentration detector | |
| JPH0117101B2 (en) | ||
| US5497618A (en) | Air/fuel control system with catalytic converter monitoring | |
| JPH06103283B2 (en) | Oxygen sensor controller | |
| KR100267325B1 (en) | Temperature compensating system for single coil idle speed control valve |