JPH09228886A - Misfire detecting method for internal combustion engine and its device - Google Patents

Misfire detecting method for internal combustion engine and its device

Info

Publication number
JPH09228886A
JPH09228886A JP3155096A JP3155096A JPH09228886A JP H09228886 A JPH09228886 A JP H09228886A JP 3155096 A JP3155096 A JP 3155096A JP 3155096 A JP3155096 A JP 3155096A JP H09228886 A JPH09228886 A JP H09228886A
Authority
JP
Japan
Prior art keywords
misfire
ignition
ion current
autocorrelation
auto
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.)
Pending
Application number
JP3155096A
Other languages
Japanese (ja)
Inventor
Juhei Takahashi
寿平 高橋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP3155096A priority Critical patent/JPH09228886A/en
Publication of JPH09228886A publication Critical patent/JPH09228886A/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P17/00—Testing of ignition installations, e.g. in combination with adjusting; Testing of ignition timing in compression-ignition engines
    • F02P17/12—Testing characteristics of the spark, ignition voltage or current
    • F02P2017/125—Measuring ionisation of combustion gas, e.g. by using ignition circuits

Landscapes

  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

PROBLEM TO BE SOLVED: To accurately detect the misfire of an ignition plug by operating the auto-correlation of ion current owing to ignition, comparing a value of the auto-correlation obtained when ion current vibrates at a specified periphery, with a specified threshold value, and thereby detecting the misfire of the ignition plug based on the result of comparison. SOLUTION: The misfire detecting device is equipped with a transistor 1 which is turned on/off by an ignition signal so as to be controlled, and one end side of the primary coil 2b of a transformer 2 is connected with the collector terminal of the transistor. The one end side of the primary coil 2b of the transformer 2 is connected with the parallel circuit of an ingnition plug 3 and a resistor R, and is furthermore connected with a CPU 8 by way of the series circuit of an impedance conversion circuit 6 and an amplifier filter circuit 7. When the ignition plug 3 is ignited so as to allow ion current to flow therein, auto-correlation vibrates at a specified period τ0 of vibration, and its period becomes the maximum when τ=τ0 . Therefore, the autocorrelation is computed based on a specified period of τ0 which is determined in advance, and smaller than a threshold when the auto-correlation, value, is recognized to be of misfire.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、点火プラグを有す
る内燃機関の失火を検知する内燃機関の失火検知方法お
よび装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine misfire detection method and apparatus for detecting an internal combustion engine misfire.

【０００２】[0002]

【従来の技術】従来、この種の失火検知装置では、点火
プラグに流れるイオン電流を検知することによって失火
または点火の検知を行っていた。図３は、このような従
来の失火検知装置を示す回路構成図である。2. Description of the Related Art Conventionally, in this type of misfire detecting device, misfire or ignition is detected by detecting an ion current flowing through an ignition plug. FIG. 3 is a circuit configuration diagram showing such a conventional misfire detection device.

【０００３】図３において、トランジスタ１はベース端
子に入力される点火信号によってオン／オフ制御され、
そのコレクタ端子にはトランス２の一次コイル２ａの一
端側が接続されている。また、トランス２の二次コイル
２ｂの一端側は点火プラグ３に接続され、さらに抵抗Ｒ
１およびダイオードＤの直列回路と抵抗Ｒ２およびコン
デンサＣの並列回路とからなる充放電回路４に接続され
ている。一次コイル２ａおよび二次コイル２ｂの各他端
側は電池５に接続されている。In FIG. 3, the transistor 1 is on / off controlled by an ignition signal input to a base terminal,
One end of the primary coil 2a of the transformer 2 is connected to the collector terminal. Further, one end of the secondary coil 2b of the transformer 2 is connected to the spark plug 3, and the resistance R
It is connected to a charging / discharging circuit 4 including a series circuit of 1 and a diode D and a parallel circuit of a resistor R2 and a capacitor C. The other ends of the primary coil 2a and the secondary coil 2b are connected to the battery 5.

【０００４】この構成において、トランジスタ１が点火
信号によってオンすると、一次コイル２ａに数Ａの電流
が流れ、二次コイル２ｂの点火プラグ３側の点には、
一次側電圧の約１００倍の電圧が発生する。図４（ａ）
および（ｂ）はトランジスタ１がオンした後に点に発
生する電圧および電流を示す。In this configuration, when the transistor 1 is turned on by the ignition signal, a current of several amperes flows through the primary coil 2a, and the secondary coil 2b has a point on the spark plug 3 side.
A voltage of about 100 times the primary voltage is generated. FIG. 4 (a)
And (b) show the voltage and current generated at the point after the transistor 1 is turned on.

【０００５】点火プラグ３は点の電圧が３０ｋＶ以上
のブレーク点に達すると放電し、その後、点には誘導
放電によって２〜３ｋＶの電圧が表れ、かつ数ｍＡの電
流が流れる。そして、１〜２msec後にはイオン電流が流
れ、このイオン電流による電圧が表れる。The spark plug 3 is discharged when the voltage at the point reaches a break point of 30 kV or more, and then a voltage of 2 to 3 kV appears at the point by inductive discharge and a current of several mA flows. Then, after 1 to 2 msec, an ion current flows, and a voltage due to this ion current appears.

【０００６】ダイオードＤのカソード側の点に表れる
電圧および電流は、点の電圧および電流の「Ｒ２／
（Ｒ１＋Ｒ２）」倍になる。この点に現れるイオン電
流または電圧を検出することによって点火プラグの点火
または失火を検出する。The voltage and current appearing at the point on the cathode side of the diode D is "R2 /
(R1 + R2) "times. Ignition or misfire of the spark plug is detected by detecting the ion current or voltage appearing at this point.

【０００７】[0007]

【発明が解決しようとする課題】前述した従来の失火検
知装置では、イオン電流が数μＡ〜数１０μＡと非常に
小さいため、点火プラグの点火または失火を確実に精度
よく検知することができないという不都合があった。In the above-described conventional misfire detection device, since the ion current is very small, from several .mu.A to several tens .mu.A, it is not possible to reliably detect ignition or misfire of the spark plug with high accuracy. was there.

【０００８】本発明は、このような従来の課題を解決す
るためになされたもので、微少なイオン電流を精度よく
検知することによって点火プラグの失火を確実に検知す
ることができる内燃機関の失火検知方法および装置を提
供することを目的とする。The present invention has been made in order to solve such a conventional problem, and misfires of an internal combustion engine capable of reliably detecting a misfire of a spark plug by accurately detecting a minute ion current. An object is to provide a detection method and device.

【０００９】[0009]

【課題を解決するための手段】本発明による内燃機関の
失火検知方法は、点火によるイオン電流の自己相関を演
算し、イオン電流が特定の周期で振動するときに得られ
る自己相関の値を所定の閾値と比較し、この比較結果に
基づき点火プラグの失火を検知する。A method for detecting misfire of an internal combustion engine according to the present invention calculates an autocorrelation of an ionic current due to ignition and determines a value of the autocorrelation obtained when the ionic current vibrates in a specific cycle. And the misfire of the spark plug is detected based on the comparison result.

【００１０】本発明によれば、微少なイオン電流を精度
よく検知することが可能となり、点火プラグの失火を確
実に検知することができる内燃機関の失火検知方法が得
られる。According to the present invention, it is possible to provide a method for detecting a misfire of an internal combustion engine, which makes it possible to detect a minute ion current with high accuracy and to reliably detect a misfire of an ignition plug.

【００１１】[0011]

【発明の実施の形態】本発明の請求項１に記載の発明
は、点火によるイオン電流の自己相関を演算すること、
イオン電流が特定の周期で振動するときに得られる自己
相関の値を所定の閾値と比較すること、この比較結果に
基づき点火プラグの失火を検知することを特徴とし、イ
オン電流が特定のスペクトルで振動することを利用して
点火によりイオン電流が生じる期間の電流波形の自己相
関を求め、ノイズに埋もれるような微少なイオン電流を
精度よく検出することによって、失火も精度よく検知で
きるという作用を有する。BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is to calculate an autocorrelation of an ion current due to ignition,
The feature is that the value of the autocorrelation obtained when the ion current oscillates in a specific cycle is compared with a predetermined threshold value, and the ignition plug misfire is detected based on the comparison result. Misfire can be accurately detected by obtaining the autocorrelation of the current waveform during the period when an ionic current is generated by ignition by utilizing the vibration and accurately detecting a minute ionic current that is buried in noise. .

【００１２】また、請求項２に記載の発明は、点火によ
るイオン電流の自己相関を演算する演算手段と、電流が
特定の周期で振動するときに得られる自己相関の値を所
定の閾値と比較する比較手段と、比較手段での比較結果
に基づき点火プラグの失火を検知する検知手段とを備え
るものであり、イオン電流が特定のスペクトルで振動す
ることを利用して点火によりイオン電流が生じる期間の
電流波形の自己相関を求め、ノイズに埋もれるような微
少なイオン電流を精度よく検出することによって、失火
も精度よく検知できるという作用を有する。The invention according to claim 2 compares the autocorrelation of the ion current due to ignition with the arithmetic means, and compares the value of the autocorrelation obtained when the current vibrates in a specific cycle with a predetermined threshold value. And a detection means for detecting the misfire of the spark plug based on the comparison result by the comparison means, and a period during which an ion current is generated by ignition by utilizing the fact that the ion current vibrates in a specific spectrum. By detecting the autocorrelation of the current waveform and accurately detecting a minute ion current that is buried in noise, misfire can be accurately detected.

【００１３】以下、本発明の実施の形態について図面を
用いて説明する。図１は、本発明の一実施の形態による
内燃機関の失火検知装置の回路構成図を示し、前述した
図３に示す構成要素と同一部分には同一符号を付して説
明する。この失火検知装置は、ベース端子に入力される
点火信号によってオン／オフ制御されるトランジスタ１
を備え、そのコレクタ端子にはトランス２の一次コイル
２ａの一端側が接続されている。An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit configuration diagram of an internal combustion engine misfire detection device according to an embodiment of the present invention, and the same components as those shown in FIG. This misfire detection device includes a transistor 1 that is on / off controlled by an ignition signal input to a base terminal.
And one end of the primary coil 2a of the transformer 2 is connected to the collector terminal thereof.

【００１４】また、トランス２の二次コイル２ｂの一端
側は、点火プラグ３および抵抗Ｒの並列回路に接続さ
れ、さらにインピーダンス変換回路（または、チャージ
アンプ）６およびアンプ・フィルタ回路７の直列回路を
経てコンピュータ（ＣＰＵ）８のＡ／Ｄ変換端子に接続
されている。また、コンピュータ８の割込みポートには
点火信号が入力されている。このコンピュータ８が本発
明の演算手段、比較手段および検知手段として機能す
る。なお、一次コイル２ａおよび二次コイル２ｂの各他
端側は電池５に接続されている。Further, one end of the secondary coil 2b of the transformer 2 is connected to a parallel circuit of a spark plug 3 and a resistor R, and a series circuit of an impedance conversion circuit (or charge amplifier) 6 and an amplifier / filter circuit 7 is connected. Is connected to the A / D conversion terminal of the computer (CPU) 8. An ignition signal is input to the interrupt port of the computer 8. The computer 8 functions as the calculating means, the comparing means, and the detecting means of the present invention. The other ends of the primary coil 2a and the secondary coil 2b are connected to the battery 5.

【００１５】次に、図２に示す波形図を参照しながら、
図１に示す失火検知装置の動作について説明する。点火
信号がトランジスタ１のベース端子に入力すると（図
ａ）、トランス２の一次コイル２ａに数Ａの電気信号が
流れる。すると、二次コイル２ｂ側の電圧が上昇し、３
０ｋＶ以上になると点火プラグ３が放電して二次コイル
２ｂ側に放電電流およびイオン電流が流れる。これは前
述の図４に示す動作と同様である。Next, referring to the waveform diagram shown in FIG.
The operation of the misfire detection device shown in FIG. 1 will be described. When the ignition signal is input to the base terminal of the transistor 1 (Fig. A), an electric signal of several A flows in the primary coil 2a of the transformer 2. Then, the voltage on the secondary coil 2b side rises,
When it becomes 0 kV or more, the spark plug 3 is discharged and a discharge current and an ionic current flow to the secondary coil 2b side. This is similar to the operation shown in FIG.

【００１６】次いで、この電流をインピーダンス変換回
路６で電圧信号に変換し、アンプ・フィルタ回路７で波
形整形してコンピュータ８のＡ／Ｄ変換端子に入力す
る。一方、点火信号はコンピュータ８の割込みポートに
も入力されているので、コンピュータ８は点火から１〜
２msecの間、Ａ／Ｄ変換端子に入力される点の信号を
Ａ／Ｄ変換する。Then, this current is converted into a voltage signal by the impedance conversion circuit 6, the waveform is shaped by the amplifier / filter circuit 7, and the voltage signal is input to the A / D conversion terminal of the computer 8. On the other hand, since the ignition signal is also input to the interrupt port of the computer 8, the computer 8 starts the ignition from 1 to
The signal at the point input to the A / D conversion terminal is A / D converted for 2 msec.

【００１７】この点の信号波形をｘ（ｔ）とすると、
自己相関Ｒ（τ）は、If the signal waveform at this point is x (t),
The autocorrelation R (τ) is

【００１８】[0018]

【数１】 となる。[Equation 1] Becomes

【００１９】もし、点火プラグ３が点火してイオン電流
が流れていれば、特定の周期τ0で振動するから（図
ｂ）、自己相関Ｒ（τ）は、τ＝τ0の周期で最大とな
る（図ｃ）。そこで、予め決定した特定の周期τ0で自
己相関Ｒ（τ0）を計算し、If the ignition plug 3 is ignited and an ionic current is flowing, it oscillates at a specific cycle τ 0 (FIG. B), so that the autocorrelation R (τ) is maximum at the cycle of τ = τ 0. (Fig. C). Therefore, the autocorrelation R (τ 0 ) is calculated at a predetermined specific period τ 0 ,

【００２０】[0020]

【数２】 このＲ（τ0）が予め設定した閾値Ｒ0よりも大きいとき
に、点火プラグ３が点火しているとコンピュータ８で判
定する。このように自己相関によってノイズに埋もれる
ような放電電流から周期性のある微少なイオン電流を検
出する。[Equation 2] When this R (τ 0 ) is larger than a preset threshold value R 0 , the computer 8 determines that the spark plug 3 is ignited. In this way, a minute ion current with periodicity is detected from the discharge current that is buried in noise due to autocorrelation.

【００２１】[0021]

【発明の効果】本発明によれば、ノイズに埋もれるよう
な放電電流から自己相関によって周期性のある信号を検
出するようにしたので、点火によって生じる微少なイオ
ン電流も精度よく検出することができ、点火プラグの失
火を精度よく検知することができる。According to the present invention, a periodic signal is detected by autocorrelation from a discharge current that is buried in noise, so that a minute ion current generated by ignition can be detected with high accuracy. The misfire of the spark plug can be accurately detected.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の一実施の形態による内燃機関の失火検
知装置を示す回路構成図FIG. 1 is a circuit configuration diagram showing a misfire detection device for an internal combustion engine according to an embodiment of the present invention.

【図２】本発明の動作を説明する波形図FIG. 2 is a waveform diagram illustrating the operation of the present invention.

【図３】従来の内燃機関の失火検知装置を示す回路構成
図FIG. 3 is a circuit configuration diagram showing a conventional misfire detection device for an internal combustion engine.

【図４】点火プラグ側の電圧・電流波形図[Figure 4] Voltage / current waveform diagram on the spark plug side

【符号の説明】[Explanation of symbols]

１ トランジスタ ２ トランス ３ 点火プラグ ６ インピーダンス変換回路 ７ アンプ・フィルタ回路 ８ コンピュータ（ＣＰＵ） 1 Transistor 2 Transformer 3 Spark plug 6 Impedance conversion circuit 7 Amplifier / filter circuit 8 Computer (CPU)

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 点火によるイオン電流の自己相関を演算
すること、 前記イオン電流が特定の周期で振動するときに得られる
前記自己相関の値を所定の閾値と比較すること、 前記比較結果に基づき前記点火プラグの失火を検知する
こと、を特徴とする内燃機関の失火検知方法。1. Computing an autocorrelation of an ionic current due to ignition, comparing the value of the autocorrelation obtained when the ionic current vibrates in a specific cycle with a predetermined threshold value, based on the comparison result. A misfire detection method for an internal combustion engine, comprising detecting misfire of the spark plug. 【請求項２】 点火によるイオン電流の自己相関を演算
する演算手段と、 前記イオン電流が特定の周期で振動するときに得られる
前記自己相関の値を所定の閾値と比較する比較手段と、 前記比較手段での比較結果に基づき前記点火プラグの失
火を検知する検知手段と、を備えることを特徴とする内
燃機関の失火検知装置。2. Computation means for computing an autocorrelation of ion current due to ignition; comparison means for comparing a value of the autocorrelation obtained when the ion current vibrates in a specific cycle with a predetermined threshold value; A misfire detection device for an internal combustion engine, comprising: a detection means for detecting misfire of the spark plug based on a comparison result by the comparison means.
JP3155096A 1996-02-20 1996-02-20 Misfire detecting method for internal combustion engine and its device Pending JPH09228886A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3155096A JPH09228886A (en) 1996-02-20 1996-02-20 Misfire detecting method for internal combustion engine and its device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3155096A JPH09228886A (en) 1996-02-20 1996-02-20 Misfire detecting method for internal combustion engine and its device

Publications (1)

Publication Number Publication Date
JPH09228886A true JPH09228886A (en) 1997-09-02

Family

ID=12334307

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3155096A Pending JPH09228886A (en) 1996-02-20 1996-02-20 Misfire detecting method for internal combustion engine and its device

Country Status (1)

Country Link
JP (1) JPH09228886A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100436795C (en) * 2005-06-23 2008-11-26 株式会社日立制作所 Misfire detection system for internal combustion engine
CN102116242A (en) * 2010-12-30 2011-07-06 天津锐意泰克汽车电子有限公司 Method for diagnosing engine misfire

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100436795C (en) * 2005-06-23 2008-11-26 株式会社日立制作所 Misfire detection system for internal combustion engine
CN102116242A (en) * 2010-12-30 2011-07-06 天津锐意泰克汽车电子有限公司 Method for diagnosing engine misfire

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