JPS6250637A - Detecting device for trouble by cylinders of internal combustion engine - Google Patents

Abstract

PURPOSE:To detect abnormality by cylinders without adding any special hardware by detecting whether a cylinder has trouble or not from the acceleration of rotation of a crank shaft right after the explosion position of each cylinder. CONSTITUTION:The rotation of the crank shaft right after the explosion in the internal combustion engine in an unloaded state is normally accelerated. Then, the time Tn' in which the crank shaft rotates by 30 deg. right after ignition and the time Tn in which the shaft rotates further by 30 deg. are calculated by using an existent crank angle sensor. The difference DELTAT=Tn'-Tn between the both is expected to exceed a constant value and found by experiment. The decrease in the DELTAT is caused by the abnormality in the cylinder. For the purpose, a detection program is incorporated in an engine control CPU to detect the DELTAT and if abnormality occurs, abnormality lamps are turned on by as many as cylinders, so abnormality by cylinders is detected without adding any hardware.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、クランク軸の回転加速度から気筒別の故障診
断を行う内燃機関の気筒別故障検知装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder-by-cylinder failure detection device for an internal combustion engine that performs cylinder-by-cylinder failure diagnosis based on the rotational acceleration of a crankshaft.

〔従来の技術〕[Conventional technology]

マイクロコンピュータを用いて燃料噴射等を制御する内
燃機関には、例えば第３図のように構成されたものがあ
る。同図において、１はエンジン、２は吸気管、３は排
気管、４は三元触媒、５はスロットル、６はエアクリー
ナ、７はエンジン制御コンビエータ（ＥＣＵ）　、８は
スロットルセンサ、９はバキュームセンサ、１０はイン
ジェクタ、１１は水温センサ、１２は０２センサ、１３
は排気温センサ、１４は吸気温センサ、１５は警告灯、
１６はスタータ、１７は点火プラグへのディストリビュ
ータとエンジン回転数およびクランク角のセンサである
。For example, there is an internal combustion engine configured as shown in FIG. 3, in which fuel injection and the like are controlled using a microcomputer. In the figure, 1 is an engine, 2 is an intake pipe, 3 is an exhaust pipe, 4 is a three-way catalyst, 5 is a throttle, 6 is an air cleaner, 7 is an engine control combinatorial unit (ECU), 8 is a throttle sensor, and 9 is a vacuum sensor , 10 is an injector, 11 is a water temperature sensor, 12 is an 02 sensor, 13
is an exhaust temperature sensor, 14 is an intake temperature sensor, 15 is a warning light,
16 is a starter, and 17 is a distributor to a spark plug and a sensor for engine speed and crank angle.

ＥＣＵ７はセンサ９によって検出される吸入空気圧とエ
ンジン回転数を基に、インジェクタ１０から噴出すべき
燃料噴射量の基本量を決定する。The ECU 7 determines the basic amount of fuel to be injected from the injector 10 based on the intake air pressure and engine rotation speed detected by the sensor 9.

この値はセンサ１１〜１４の出力で補正される。This value is corrected by the outputs of the sensors 11-14.

これがＥＣＵ７の機能の１つ（燃料噴射制御）である。This is one of the functions of the ECU 7 (fuel injection control).

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

ところで、エンジン１は一般に複気筒であって、各気筒
毎に点火プラグやインジェクタがあり、これらの良否や
圧縮比の良否は全体に影響する。ところが、従来は気筒
別の故障検知、機構がないため、多気筒のエンジンでは
不調時にどの気筒が故障しているかを即断できない。本
発明はＥＣＵ７のプログラムで気筒別の故障診断を行お
うとするものである。By the way, the engine 1 is generally a multi-cylinder engine, and each cylinder has a spark plug and an injector, and the quality of these and the quality of the compression ratio affects the entire engine. However, in the past, there was no failure detection mechanism for each cylinder, so it was not possible to immediately determine which cylinder was malfunctioning in a multi-cylinder engine. The present invention attempts to perform failure diagnosis for each cylinder using a program of the ECU 7.

〔問題点を解決するための手段〕[Means for solving problems]

本発明は、複気筒の内燃機関の無負荷回転時に、各気筒
の爆発位置直後のクランク軸の回転加速度を検知し、そ
の値を基準値と比較して気筒別の故障の有無を検知する
ようにしてなることを特徴とするものである。The present invention detects the rotational acceleration of the crankshaft immediately after the explosion position of each cylinder during no-load rotation of a multi-cylinder internal combustion engine, and compares that value with a reference value to detect the presence or absence of a failure in each cylinder. It is characterized by:

〔作用〕[Effect]

内燃機関の無負荷時（アイドル時）に爆発直後のクラン
ク軸の回転は加速されるのが普通であるので、その回転
加速度を気筒別に計測すれば故障状態の気筒を容易に判
別できる。しかも、クランク軸の回転加速度は既存のク
ランク角センサの出力から計測できるので、ハード構成
を追加せずに実施することができる。また検出した故障
気筒番号はランプの点灯回数等で表示すれば良く、これ
も既存の警告灯を併用することができる。Normally, the rotation of the crankshaft immediately after an explosion is accelerated when the internal combustion engine is under no load (idling), so by measuring the rotational acceleration for each cylinder, it is easy to identify which cylinder is in a faulty state. Moreover, since the rotational acceleration of the crankshaft can be measured from the output of the existing crank angle sensor, it can be implemented without adding any hardware configuration. Further, the detected faulty cylinder number may be displayed by the number of times a lamp is turned on, etc., and an existing warning light can also be used for this purpose.

〔実施例〕〔Example〕

第１図は本発明の原理説明図で、４気筒の内燃機関を例
としている。４気筒の爆発（点火）順序は第１＝第４＝
第２＝第３＝第１の順で、（ａ）のように全てが正常で
あれば点火直後にクランク軸が３０’凹転する時間Ｔｎ
’　　（ｎ＝１〜４）とその次の３０°を回転する時間
Ｔｎとの差（回転加速度） ΔＴ　＝　Ｔ　ｎ’　−Ｔ　ｎ　　　　　　　　−・・
・（１）は一定値を越えるはずである。この一定値は実
験により求めることができる値で、所定回転数で定めら
れた異常判定値である。FIG. 1 is a diagram explaining the principle of the present invention, taking a four-cylinder internal combustion engine as an example. The explosion (ignition) order of the 4 cylinders is 1st = 4th =
In the order of 2nd = 3rd = 1st, if everything is normal as in (a), the time Tn for the crankshaft to rotate 30' concave immediately after ignition
' (n=1 to 4) and the time Tn for rotating the next 30 degrees (rotational acceleration) ΔT = T n' - T n -...
・(1) should exceed a certain value. This constant value can be obtained through experiments, and is an abnormality determination value determined at a predetermined rotation speed.

同図中）は第４気筒目に異常が生じるでいる場合である
。この異常は第４気筒のプラグが点火しないか、インジ
ェクタが燃料を供給しないか、或いは圧縮比の低下等に
より爆発不良となり、Ｔ２が同図（ａ）より大となって
回転加速度ΔＴが上記の一定値より低下したものである
。このΔＴの低下は他の気筒では観測されないので、第
４気筒だけが故障していると判定できる。(in the figure) is a case where an abnormality occurs in the fourth cylinder. This abnormality is caused by the plug in the 4th cylinder not igniting, the injector not supplying fuel, or a drop in the compression ratio resulting in an explosion failure, and T2 becomes larger than that shown in (a) in the same figure, causing the rotational acceleration ΔT to exceed the above value. It is lower than a certain value. Since this decrease in ΔT is not observed in other cylinders, it can be determined that only the fourth cylinder is malfunctioning.

同図（Ｃ）はクランク角の説明図である。第３図のセン
サ１７はクランク角信号を発生するが、これには一般に
３０°毎の信号と基準位置を定める３６０°信号等があ
る。また、多気筒の場合、どの気筒が点火時期になって
いるかを示す信号も別にある。FIG. 2C is an explanatory diagram of the crank angle. Sensor 17 in FIG. 3 generates crank angle signals, which generally include signals every 30 degrees and 360 degrees signals defining a reference position. In addition, in the case of a multi-cylinder engine, there is also a separate signal that indicates which cylinder has the ignition timing.

第２図は本発明の一実施例を示すフローチャー１・で、
これは第３図のＥＣＵ７のプログラムの一部に組込まれ
る。この回転加速度検出ルーチン↓よ、アイドル状態で
あること、およびエンジン冷却水温が例えば８０°Ｃ以
上であること等を条件に実行され、異常は警告灯１５の
１つを気筒番号の数だけ点灯させるような方法で報知す
る。FIG. 2 is a flowchart 1 showing an embodiment of the present invention.
This is incorporated into a part of the program of the ECU 7 shown in FIG. This rotational acceleration detection routine ↓ is executed under the conditions that the engine is in an idling state and that the engine cooling water temperature is, for example, 80°C or higher, and if an abnormality occurs, one of the warning lights 15 lights up for the number of cylinders. Notify in such a way.

〔発明の効果〕〔Effect of the invention〕

以上述べたように本発明によれば、マイクロコンピュー
タで制御する内燃機関の気筒別異常を特別なハード構成
を追加することなく検知して報知できる利点がある。As described above, the present invention has the advantage of being able to detect and notify abnormalities in each cylinder of an internal combustion engine controlled by a microcomputer without adding any special hardware configuration.

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

第１図は本発明の原理説明図、第２図は本発明の一実施
例を示すフローチャート、第３図はコンピュータ制御型
内燃機関の一例を示すブロック図である。 図中、１はエンジン、７はエンジン制御コンピュータ、
１０はインジェクタ、１７はクランク角センサである。 出　願　人　　富士通テン株式会社 代理人弁理士　　青　　柳　　　稔 （ｄ）正１ｇ吋 ΔＴ＋”Ｔ＋’−ＴｌΔｒ２＝ｒ２’−ｖ２ΔＴ３．Ｔ
３’−Ｔ３Δ：ｒ４−ｒ４−ｒ４（ｂ）才４気筒＊宇 本イし岨０原ｖ！ｇ愛２日口図 本誉岨の７０−＋ヤード ｊＩ２図 システム楕ａＵ２FIG. 1 is a diagram illustrating the principle of the present invention, FIG. 2 is a flow chart showing an embodiment of the present invention, and FIG. 3 is a block diagram showing an example of a computer-controlled internal combustion engine. In the figure, 1 is an engine, 7 is an engine control computer,
10 is an injector, and 17 is a crank angle sensor. Applicant Fujitsu Ten Ltd. Representative Patent Attorney Minoru Aoyagi (d) Positive 1g ΔT+”T+'-TlΔr2=r2'-v2ΔT3.T
3'-T3Δ: r4-r4-r4 (b) 4-cylinder * Umoto Ishi 0 Hara v! g Ai 2nd Exit Map Ben Yoshi's 70-+ Yard j I 2 Diagram System Ellipse aU2

Claims (1)

【特許請求の範囲】[Claims] 複気筒の内燃機関の無負荷回転時に、各気筒の爆発位置
直後のクランク軸の回転加速度を検知し、その値を基準
値と比較して気筒別の故障の有無を検知するようにして
なることを特徴とする内燃機関の気筒別故障検知装置。During no-load rotation of a multi-cylinder internal combustion engine, the rotational acceleration of the crankshaft immediately after the explosion position of each cylinder is detected, and that value is compared with a reference value to detect whether or not there is a failure in each cylinder. A failure detection device for each cylinder of an internal combustion engine, which is characterized by: