JP2007205321A - Method for detecting air fuel ratio by ion current in internal combustion engine - Google Patents

Method for detecting air fuel ratio by ion current in internal combustion engine Download PDF

Info

Publication number
JP2007205321A
JP2007205321A JP2006028126A JP2006028126A JP2007205321A JP 2007205321 A JP2007205321 A JP 2007205321A JP 2006028126 A JP2006028126 A JP 2006028126A JP 2006028126 A JP2006028126 A JP 2006028126A JP 2007205321 A JP2007205321 A JP 2007205321A
Authority
JP
Japan
Prior art keywords
cylinder
fuel ratio
generation period
variation rate
air
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.)
Granted
Application number
JP2006028126A
Other languages
Japanese (ja)
Other versions
JP4592612B2 (en
Inventor
Morihito Asano
守人 浅野
Yoshiyuki Fukumura
義之 福村
Mitsuhiro Izumi
光宏 泉
Koichi Satoya
浩一 里屋
Mamoru Yoshioka
衛 吉岡
Koichi Kitaura
浩一 北浦
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.)
Daihatsu Motor Co Ltd
Toyota Motor Corp
Diamond Electric Manufacturing Co Ltd
Original Assignee
Daihatsu Motor Co Ltd
Toyota Motor Corp
Diamond Electric Manufacturing 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 Daihatsu Motor Co Ltd, Toyota Motor Corp, Diamond Electric Manufacturing Co Ltd filed Critical Daihatsu Motor Co Ltd
Priority to JP2006028126A priority Critical patent/JP4592612B2/en
Publication of JP2007205321A publication Critical patent/JP2007205321A/en
Application granted granted Critical
Publication of JP4592612B2 publication Critical patent/JP4592612B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To execute more accurate air fuel ratio control right after engine start. <P>SOLUTION: Generation period P is measured from ion current I detected from an inside of a combustion chamber 30 of each cylinder of a multiple cylinder engine 100. Air fuel ratio of each cylinder is detected based on all cylinder fluctuation rate NA operated based on generation period P of all cylinders in operation of the engine 100 from initial explosion to predetermined cycles, and air fuel ratio of each cylinder is detected based on cylinder fluctuation rate N operated based on generation period P of each cylinder in operation of the internal combustion engine after the predetermined cycles (S5). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、内燃機関のイオン電流による空燃比検知方法に関するものである。   The present invention relates to an air-fuel ratio detection method using an ionic current of an internal combustion engine.

従来、車両に搭載される内燃機関（以下、エンジンと称する）では、排気ガス中の酸素濃度をＯ2 センサによって測定し、その測定値に基づいて燃料噴射量を調節することによって空燃比の制御が行われている。 Conventionally, in an internal combustion engine (hereinafter referred to as an engine) mounted on a vehicle, the oxygen concentration in exhaust gas is measured by an O 2 sensor, and the fuel injection amount is adjusted based on the measured value, thereby controlling the air-fuel ratio. Has been done.

また一方で、燃焼室内に発生するイオン電流を検出して燃焼状態を判定し、当該判定に基づいて燃料噴射量を調節することによって、空燃比制御を行うことも試みられている。具体的には、点火後に燃焼室に発生するイオン電流が、検出のために設定される閾値を上回ることによりイオン電流を検出し、閾値を上回ったイオン電流が発生した発生期間に基づいて燃焼状態が良好であるか否かを判定するものである。具体的には、イオン電流発生期間の変動率を気筒毎に演算し、この気筒毎に演算した発生期間の気筒別変動率が所定値以上となった場合、すなわち発生期間のばらつきが所定以上となった場合、その気筒がリーン限界になっていると判断するものが挙げられる（例えば、特許文献1参照）。
特許第３１５０４２９号明細書 On the other hand, it is also attempted to perform air-fuel ratio control by detecting the ionic current generated in the combustion chamber to determine the combustion state and adjusting the fuel injection amount based on the determination. Specifically, the ionic current generated in the combustion chamber after ignition exceeds the threshold set for detection, the ionic current is detected, and the combustion state is based on the generation period in which the ionic current exceeding the threshold is generated. It is determined whether or not is good. Specifically, the variation rate of the ion current generation period is calculated for each cylinder, and when the variation rate for each cylinder in the generation period calculated for each cylinder is equal to or greater than a predetermined value, that is, the variation in the generation period is equal to or greater than a predetermined value. In such a case, it may be determined that the cylinder is at the lean limit (see, for example, Patent Document 1).
Japanese Patent No. 3150429

ここで近年、エンジンの燃費向上並びに排気エミッションのさらなる削減を目指すために、従来は燃料噴射が多めに設定されたエンジンの始動直後においても燃料噴射を少なくし余剰燃料の排出を抑制するという、いわゆる始動時リーン制御の実現が望まれている。   In recent years, in order to improve the fuel consumption of the engine and further reduce the exhaust emission, the so-called fuel injection is reduced and the discharge of surplus fuel is suppressed even immediately after the start of the engine where the fuel injection has been set to be large. Realization of lean control at start-up is desired.

しかしながら従来のＯ2 センサの測定値による空燃比制御では、Ｏ2 センサの温度が十分に高められ活性化するまでは正確な検出値が得られないため、始動直後においては適用できないものとなっている。 However, in the air-fuel ratio control by the measured values of the conventional O 2 sensor, since the O 2 until the temperature of the sensor is activated elevated sufficiently not obtained accurate detection value, so shall not be applied immediately after the start Yes.

また上述の特許文献のような構成のものであると、エンジンの始動直後はイオン電流の発生期間のサンプル数が少ないため、ある気筒において空燃比が制御目標値から外れた燃焼が悪い状態を継続しイオン電流発生期間が変動していない場合には、気筒別変動率が低く算出されてしまう。そのため、このような場合では燃焼が悪い状態が変動率を通じて現れるのはその後に発生期間が変動した後となるため、燃焼が悪い状態が起こってからその状態が変動率として現れるまでに遅れが生じてしまい、その間的確な制御を行うことができないこととなる。また、サンプル数が少ない状態では個々のサンプルの影響が大きすぎて、発生期間の変動が突発的に現れてしまう事も起こり、その影響も受け易いものとなっている。これらのようなことから、気筒別変動率に基づく制御を始動時に適用しても、的確な空燃比制御に基づく良好な排気エミッションの削減効果並びに燃費向上効果が得られないものとなってしまう。   In addition, with the configuration as described in the above-mentioned patent document, the number of samples in the generation period of the ionic current is small immediately after the engine is started, so that the combustion in which the air-fuel ratio deviates from the control target value in a certain cylinder continues to be poor. However, when the ion current generation period does not vary, the variation rate for each cylinder is calculated to be low. Therefore, in such a case, the state where the combustion is poor appears through the fluctuation rate after the occurrence period fluctuates thereafter, and there is a delay between the occurrence of the bad combustion and the appearance of the state as the fluctuation rate. As a result, accurate control cannot be performed. In addition, when the number of samples is small, the influence of individual samples is too great, and the occurrence period may suddenly appear, which is easily affected. For these reasons, even if the control based on the cylinder-by-cylinder variation rate is applied at the time of start-up, a good exhaust emission reduction effect and fuel efficiency improvement effect based on accurate air-fuel ratio control cannot be obtained.

そこで本発明は、エンジンの始動直後における空燃比の制御を気筒毎に、より的確に行うことを目的としている。   Accordingly, an object of the present invention is to more accurately perform control of the air-fuel ratio immediately after engine startup for each cylinder.

すなわち、本発明に係る内燃機関のイオン電流による空燃比検知方法は、多気筒の内燃機関におけるそれぞれの気筒の燃焼室内に発生するイオン電流を検出し、検出したイオン電流の発生している発生期間を計測し、当該発生期間を基に演算した各気筒における変動率に基づいて各気筒の空燃比を検知し得るものであって、少なくとも内燃機関の運転が初爆から所定サイクルになるまでの間は、計測した全気筒における発生期間を基に算出された全気筒変動率に基づいて各気筒の空燃比を検知する事を特徴としている。   That is, the air-fuel ratio detection method using an ion current of an internal combustion engine according to the present invention detects an ion current generated in the combustion chamber of each cylinder in a multi-cylinder internal combustion engine, and a generation period in which the detected ion current is generated The air-fuel ratio of each cylinder can be detected based on the fluctuation rate in each cylinder calculated based on the generation period, and at least during the operation of the internal combustion engine from the initial explosion to a predetermined cycle Is characterized in that the air-fuel ratio of each cylinder is detected based on the all-cylinder fluctuation rate calculated based on the occurrence period in all the measured cylinders.

ここで、「所定サイクル」とは、各気筒において変動率の演算のために最小限必要な発生期間のサンプル数を確保するまでのサイクル数、すなわち十分なサンプル数をもって気筒別変動率を演算し得るまでのサイクル数を指すものとする。   Here, “predetermined cycle” means that the variation rate for each cylinder is calculated with the number of cycles until a minimum number of samples for the occurrence period required for calculating the variation rate for each cylinder is secured, that is, with a sufficient number of samples. Refer to the number of cycles to obtain.

このようなものであれば、内燃機関の始動時すなわち初爆から所定サイクルまでの間といった発生期間のサンプル数が少ない段階では、全気筒からの発生期間をサンプリングして演算した全気筒変動率を採用することにより、所定サイクルが経過するまでの間の発生期間の変動を、全気筒から検出されたイオン電流の発生期間を基に判定するため、初爆直後から十分量のサンプル数を得ることができ、始動直後から正確な変動率を得ることができる。加えて、発生期間の変動を早く検知することが可能となる。そうすることにより、始動直後から正確な空燃比制御を行うことができる。さらに、十分量のサンプル量を始動直後から得られるので始動直後に発生期間が突発的に変動してもその影響を過度に受けた空燃比制御を行ってしまうことを有効に回避することができる。また、所定サイクルを経た後、すなわち十分なサンプル数が得られる状態となれば、例えば気筒別変動率に切り換えて空燃比の制御を行うなど、その状態に応じた制御を行えばよい。   If this is the case, at the start of the internal combustion engine, that is, at a stage where the number of samples in the generation period, such as from the first explosion to a predetermined cycle, is small, the variation rate of all cylinders calculated by sampling the generation period from all cylinders is calculated. By adopting, to determine the fluctuation of the generation period until the predetermined cycle elapses based on the generation period of ion current detected from all cylinders, obtain a sufficient number of samples immediately after the first explosion And an accurate variation rate can be obtained immediately after starting. In addition, it is possible to quickly detect the change in the generation period. By doing so, accurate air-fuel ratio control can be performed immediately after startup. Furthermore, since a sufficient amount of sample can be obtained immediately after startup, even if the generation period suddenly changes immediately after startup, it is possible to effectively avoid performing air-fuel ratio control that is excessively affected by this. . Further, after a predetermined cycle, that is, when a sufficient number of samples can be obtained, the control according to the state may be performed, for example, the air-fuel ratio is controlled by switching to the variation rate for each cylinder.

本発明は、以上説明したような構成であり、発生期間のサンプル数が少ない段階である初爆から所定サイクルまでの間は全気筒からデータをサンプリングする全気筒変動率を採用することにより、始動直後において、ある気筒の空燃比が制御目標値から外れるために起因する発生期間の変動を早いタイミングで検知して的確なタイミングで空燃比の制御を行うことができる。   The present invention is configured as described above, and starts by adopting an all-cylinder variation rate that samples data from all cylinders from the initial explosion to a predetermined cycle, where the number of samples in the generation period is small. Immediately after that, it is possible to detect the fluctuation of the generation period due to the fact that the air-fuel ratio of a certain cylinder deviates from the control target value at an early timing and to control the air-fuel ratio at an accurate timing.

本発明の第一実施形態について、図面を参照して説明する。   A first embodiment of the present invention will be described with reference to the drawings.

図１に概略的に示したエンジン１００は、自動車用の火花点火式４サイクル４気筒のもので、その吸気系１には図示しないアクセルペダルに応動して開閉するスロットルバルブ２が配設され、その下流側にはサージタンク３が設けられている。サージタンク３に連通する一方の端部近傍には、さらに燃料噴射弁５が設けてあり、その燃料噴射弁５を、電子制御装置６により制御するようにしている。燃焼室３０を形成するシリンダヘッド３１には、吸気弁３２及び排気弁３３が配設されるとともに、火花を発生するとともにイオン電流Ｉを検出するための電極となるスパークプラグ１８が取り付けてある。また排気系２０には、排気ガス中の酸素濃度を測定するためのＯ2 センサ２１が、図示しないマフラに至るまでの管路に配設された触媒装置である三元触媒２２の上流の位置に取り付けられている。なお、図１にあっては、エンジン１００が有する第一気筒１００ａ、第二気筒１００ｂ、第三気筒１００ｃ並びに第四気筒１００ｄのうち、第一気筒１００ａの構成を代表して図示している。 An engine 100 schematically shown in FIG. 1 is a spark-ignition four-cycle four-cylinder engine for an automobile. A throttle valve 2 that opens and closes in response to an accelerator pedal (not shown) is disposed in an intake system 1 thereof. A surge tank 3 is provided on the downstream side. A fuel injection valve 5 is further provided in the vicinity of one end communicating with the surge tank 3, and the fuel injection valve 5 is controlled by the electronic control unit 6. The cylinder head 31 forming the combustion chamber 30 is provided with an intake valve 32 and an exhaust valve 33, and with a spark plug 18 that generates sparks and serves as an electrode for detecting the ionic current I. Further, in the exhaust system 20, an O 2 sensor 21 for measuring the oxygen concentration in the exhaust gas is located upstream of the three-way catalyst 22 which is a catalyst device arranged in a pipe line leading to a muffler (not shown). Is attached. In FIG. 1, the configuration of the first cylinder 100a among the first cylinder 100a, the second cylinder 100b, the third cylinder 100c, and the fourth cylinder 100d of the engine 100 is shown as a representative.

電子制御装置６は、中央演算処理装置７と、記憶装置８と、入力インターフェース９と、出力インターフェース１１と、Ａ／Ｄコンバータ１０とを具備してなるマイクロコンピュータシステムを主体に構成されている。入力インターフェース９には、サージタンク３内の圧力すなわち吸気管圧力を検出するための吸気圧センサ１３から出力される吸気圧信号ａ、エンジン１００の回転状態を検出するためのカムポジションセンサ１４から出力される気筒判別信号Ｇ１とクランク角度基準位置信号Ｇ２とエンジン回転数信号ｂ、車速を検出するための車速センサ１５から出力される車速信号ｃ、スロットルバルブ２の開閉状態を検出するためのアイドルスイッチ１６から出力されるＩＤＬ信号ｄ、エンジン１００の冷却水温を検出するための水温センサ１７から出力される水温信号ｅ、上記したＯ2 センサ２１から出力される電流信号ｈ等が入力される。一方、出力インターフェース１１からは、燃料噴射弁５に対して燃料噴射信号ｆが、またスパークプラグ１８に対してイグニションパルスｇが出力されるようになっている。 The electronic control device 6 is mainly configured by a microcomputer system including a central processing unit 7, a storage device 8, an input interface 9, an output interface 11, and an A / D converter 10. The input interface 9 includes an intake pressure signal a output from an intake pressure sensor 13 for detecting the pressure in the surge tank 3, that is, an intake pipe pressure, and an output from a cam position sensor 14 for detecting the rotation state of the engine 100. Cylinder discrimination signal G1, crank angle reference position signal G2, engine speed signal b, vehicle speed signal c output from the vehicle speed sensor 15 for detecting the vehicle speed, idle switch for detecting the open / closed state of the throttle valve 2 The IDL signal d output from 16, the water temperature signal e output from the water temperature sensor 17 for detecting the coolant temperature of the engine 100, the current signal h output from the O 2 sensor 21, etc. are input. On the other hand, the output interface 11 outputs a fuel injection signal f to the fuel injection valve 5 and an ignition pulse g to the spark plug 18.

このスパークプラグ１８には、イオン電流Ｉを測定するためのバイアス用電源２４が接続され、入力インターフェース９とこのバイアス電源２４との間にはイオン電流測定用回路２５が接続されている。スパークプラグ１８、バイアス用電源２４、イオン電流測定用回路２５によりイオン電流検出系４０が構成される。バイアス用電源２４は、イグニションパルスｇが消滅した時点でスパークプラグ１８にイオン電流Ｉの測定のための測定用電圧（バイアス電圧）を印加するものである。そして、測定用電圧の印加により、燃焼室３０の内壁とスパークプラグ１８の中心電極との間、及びスパークプラグ１８の電極間に流れたイオン電流Ｉは、イオン電流測定用回路２５により測定される。そしてイオン電流測定用回路２５は、測定したイオン電流Ｉの電流値に対応するイオン電流信号を電子制御装置６に出力する。このようなバイアス用電源２４とイオン電流測定用回路２５とは、当該分野でよく知られている種々のものを適用することができる。   A bias power source 24 for measuring the ion current I is connected to the spark plug 18, and an ion current measuring circuit 25 is connected between the input interface 9 and the bias power source 24. The spark plug 18, the bias power supply 24, and the ion current measurement circuit 25 constitute an ion current detection system 40. The bias power supply 24 applies a measurement voltage (bias voltage) for measuring the ion current I to the spark plug 18 at the time when the ignition pulse g disappears. The ion current I flowing between the inner wall of the combustion chamber 30 and the center electrode of the spark plug 18 and between the electrodes of the spark plug 18 by applying the measurement voltage is measured by the ion current measuring circuit 25. . Then, the ion current measurement circuit 25 outputs an ion current signal corresponding to the measured current value of the ion current I to the electronic control device 6. As the bias power source 24 and the ion current measuring circuit 25, various devices well known in the art can be applied.

イオン電流Ｉは、例えば理論空燃比近傍における良好な燃焼状態では、上死点手前で減少した後に時間の経過とともに再度増加し、燃焼圧が最大となるクランク角度近傍でその電流値が最大となり、そして徐々に減少して通常、膨張行程の終了近傍において消滅するといった挙動を示す（図示せず）。しかし、何らかの原因で燃焼状態が良好でなく失火に近い燃焼を示すときは、燃焼圧が十分に上昇しないために、電流値が低くなる傾向にある。   For example, in a good combustion state in the vicinity of the theoretical air-fuel ratio, the ion current I decreases again before the top dead center and then increases again as time elapses, and the current value becomes maximum near the crank angle at which the combustion pressure becomes maximum, Then, it gradually decreases and normally behaves in the vicinity of the end of the expansion stroke (not shown). However, when the combustion state is not good for some reason and indicates combustion close to misfire, the combustion pressure does not rise sufficiently, and the current value tends to be low.

発生期間Ｐは本実施形態において、上述のような挙動を示すイオン電流Ｉに基づいて燃焼状態を判定するため、例えば判定レベルである閾値（スレッショルドレベル）を予め設定することによって、イオン電流Ｉの電流値あるいはその電流による電圧が前記閾値を超えて検出される期間を示す値としている。なお、空燃比を理論空燃比より高くして燃料制御を行う希薄燃焼制御（リーン燃焼制御）においては、燃料の供給量を減少させていくと、安定した燃焼状態を維持し得る限界の燃焼状態に近づくにつれて燃焼状態が緩慢になる。このように燃焼状態が緩慢になると、イオン電流Ｉの発生している発生期間Ｐが長くなったり、逆に短くなったりすることによって、その長さがサイクル毎に且つ気筒毎にばらつくといった挙動を示す。そして、図２（ａ）は、初爆から各気筒より検出される発生期間Ｐを図示したグラフである。なお同図において、４つの気筒１００ａ、１００ｂ、１００ｃ、１００ｄの燃焼に基づく４つの発生期間Ｐの検出をもってエンジン１００の１サイクルとしている。また同図（ｂ）及び同図（ｃ）は、同図（ａ）に対応する後述する気筒別変動率Ｎ及び全気筒変動率ＮＡの挙動をそれぞれ示している。   In the present embodiment, the generation period P is determined based on the ion current I exhibiting the behavior as described above. Therefore, for example, by setting a threshold value (threshold level) that is a determination level in advance, It is a value indicating a period during which the current value or the voltage due to the current is detected exceeding the threshold value. In lean combustion control (lean combustion control) in which fuel control is performed with the air-fuel ratio higher than the stoichiometric air-fuel ratio, the limit of the combustion state that can maintain a stable combustion state when the fuel supply amount is decreased. As it approaches, the combustion state becomes slow. When the combustion state becomes slow in this way, the generation period P in which the ionic current I is generated becomes longer or conversely shortened, so that the length varies from cycle to cycle and from cylinder to cylinder. Show. FIG. 2A is a graph illustrating the generation period P detected from each cylinder from the first explosion. In the figure, one cycle of the engine 100 is determined by detecting four generation periods P based on the combustion of the four cylinders 100a, 100b, 100c, and 100d. Further, FIGS. 7B and 7C respectively show the behaviors of the cylinder-by-cylinder variation rate N and the all-cylinder variation rate NA, which will be described later, corresponding to FIG.

電子制御装置６には、エンジン１００の運転が初爆から所定サイクルになるまでの間は計測した発生期間Ｐに基づいて演算した全気筒変動率ＮＡに基づいて空燃比を検知し前記所定サイクル以降では計測した発生期間Ｐに基づいて演算した気筒別変動率Ｎに基づいて空燃比を検知することによって、各気筒１００ａ、１００ｂ、１００ｃ、１００ｄに配された４つの燃料噴射弁５から噴射される燃料噴射量をそれぞれ調節するプログラムが内蔵してある。また、本実施形態において具体的には、演算した気筒別変動率Ｎ又は全気筒変動率ＮＡと判定値ＯＶとをそれぞれ比較し、比較の結果、前記気筒別変動率Ｎ又は全気筒変動率ＮＡが判定値ＯＶを超えている場合に空燃比がリーン側に変化したことを検知するようにプログラミングされているものである。   The electronic control unit 6 detects the air-fuel ratio based on the variation rate NA of all cylinders calculated based on the measured generation period P until the engine 100 is operated from the initial explosion until the predetermined cycle, and after the predetermined cycle. In this case, the air-fuel ratio is detected based on the cylinder-specific variation rate N calculated based on the measured generation period P, so that the fuel is injected from the four fuel injection valves 5 disposed in each cylinder 100a, 100b, 100c, 100d. There is a built-in program for adjusting the fuel injection amount. Further, in the present embodiment, specifically, the calculated cylinder-specific variation rate N or all-cylinder variation rate NA is compared with the determination value OV, respectively. As a result of the comparison, the cylinder-specific variation rate N or all-cylinder variation rate NA is compared. Is programmed to detect that the air-fuel ratio has changed to the lean side when the value exceeds the determination value OV.

ここで所定サイクルとは、本実施形態において、各気筒において検出される発生期間Ｐを基に本実施形態に係る制御に採用するに足る気筒別変動率Ｎを演算するための最小限のサンプル数を検出するまでのサイクル数として予め定められたものである。例えば同実施形態では、後述する図３に係る基準値を８に設定し、８個の発生期間Ｐをサンプルとして気筒別変動率Ｎを演算している。すなわち、本実施形態に係る所定サイクルを８サイクルに設定している。   Here, in the present embodiment, the predetermined cycle is the minimum number of samples for calculating the variation rate N for each cylinder that can be used for the control according to the present embodiment based on the generation period P detected in each cylinder. This is predetermined as the number of cycles until detection of. For example, in this embodiment, a reference value according to FIG. 3 to be described later is set to 8, and the variation rate N for each cylinder is calculated using eight occurrence periods P as samples. That is, the predetermined cycle according to the present embodiment is set to 8 cycles.

判定値ＯＶは、上述のようにして得る発生期間Ｐの気筒別変動率Ｎ或いは全気筒変動率ＮＡに対して、変動の大きさを判定するための基準、すなわち判定値ＯＶを、例えば５０％に設定している。したがって本実施形態では、気筒別変動率Ｎ及び全気筒変動率ＮＡを演算するためのサンプルとして用いる発生期間Ｐのばらつきが判定値ＯＶよりも小さい、すなわち所定のばらつき度合いよりも発生期間Ｐがそろっている際には燃焼状態を良好と判定し、一方、サンプルとして用いる発生期間Ｐのばらつきが所定値よりも大きい、すなわち所定のばらつき度合いを超えて発生期間Ｐがばらついている際には燃焼状態を不良と判定するものである。   The determination value OV is, for example, 50% of a reference for determining the magnitude of the change, that is, the determination value OV, with respect to the change rate N for each cylinder or the change rate NA for all cylinders in the generation period P obtained as described above. It is set to. Therefore, in this embodiment, the variation of the generation period P used as a sample for calculating the cylinder specific variation rate N and the total cylinder variation rate NA is smaller than the determination value OV, that is, the generation period P is more than a predetermined variation degree. When the combustion period is determined to be good, the variation in the generation period P used as a sample is larger than a predetermined value, that is, when the generation period P varies beyond a predetermined degree of variation, the combustion state is determined. Is determined to be defective.

気筒別変動率Ｎは、図２（ｂ）に示すように、エンジン１００のそれぞれの気筒毎にそれぞれ発生するイオン電流Ｉの発生期間Ｐを基に演算するものとしている。例えば本実施形態では、今回検出した発生期間Ｐとそれ以前に検出された例えば７個の発生期間Ｐとの計８個の発生期間Ｐから平均と標準偏差とを演算し、当該偏差を前記平均値で除した値を変動率として演算している。また同図において、エンジン１００の初爆からの発生期間Ｐの検出数が８に満たない場合をも図示しているが、検出された８よりも少ない個数を基に上記同様の変動率を演算して図示している。なお前記標準偏差に代えて、統計における分散を採用しても良い。また同図において、例えば第一気筒１００ａにおける気筒別変動率Ｎの挙動は、最初の３回までの発生期間Ｐはそれぞれ略同様の値を検出しているため、判定値ＯＶよりも低い値を示している。その後、第一気筒１００ａの発生期間Ｐが他の３つの気筒と略同様の値を検出するようになると、前記３回までの発生期間Ｐを含んで演算される気筒別変動率Ｎは上昇し判定値ＯＶを超える挙動を示すようになる。   The variation rate N for each cylinder is calculated based on the generation period P of the ionic current I generated for each cylinder of the engine 100 as shown in FIG. For example, in the present embodiment, an average and a standard deviation are calculated from a total of eight occurrence periods P of the occurrence period P detected this time and, for example, seven occurrence periods P detected before that, and the deviation is calculated as the average. The value divided by the value is calculated as the fluctuation rate. In addition, in the same figure, the case where the number of detections of the generation period P from the first explosion of the engine 100 is less than 8 is also illustrated, but the variation rate similar to the above is calculated based on the number less than 8 detected. It is illustrated. Instead of the standard deviation, variance in statistics may be adopted. Further, in the figure, for example, the behavior of the variation rate N for each cylinder in the first cylinder 100a is detected to be a value lower than the determination value OV since the substantially same value is detected in the first three occurrence periods P. Show. Thereafter, when the generation period P of the first cylinder 100a detects a value substantially similar to that of the other three cylinders, the cylinder specific variation rate N calculated including the generation period P up to three times increases. A behavior exceeding the judgment value OV is exhibited.

全気筒変動率ＮＡは、図２（ｃ）に示すように、エンジン１００のうち全ての気筒すなわち第一気筒１００ａ、第二気筒１００ｂ、第三気筒１００ｃ及び第四気筒１００ｄにおいてそれぞれ発生するイオン電流Ｉの発生期間Ｐから演算するものとしている。例えば本実施形態では、検出した発生期間Ｐとそれ以前に検出された例えば７個の発生期間Ｐとの計８個の発生期間Ｐから平均と標準偏差とを演算し、当該偏差を前記平均値で除した値を変動率として演算している。また同図において、エンジン１００の初爆からの全気筒の発生期間Ｐの合計検出数が８に満たない場合は、検出された８よりも少ない個数を基に演算したものとして図示している。なお全気筒変動率ＮＡにおいても前記標準偏差に代えて、統計における分散を用いても良い。また同図において、全気筒変動率ＮＡの挙動は、第一気筒１００ａにおける最初の３回までの発生期間Ｐが第二気筒１００ｂ、第三気筒１００ｃ及び第四気筒１００ｄとは異なる値を検出しているため、最初の３回の発生期間Ｐを検出した際に、全気筒変動率ＮＡは、判定値ＯＶを超える挙動を示している。   As shown in FIG. 2C, the total cylinder fluctuation rate NA is an ionic current generated in all cylinders of the engine 100, that is, the first cylinder 100a, the second cylinder 100b, the third cylinder 100c, and the fourth cylinder 100d. It is assumed that the calculation is performed from the generation period P of I. For example, in the present embodiment, an average and a standard deviation are calculated from a total of eight occurrence periods P including a detected occurrence period P and, for example, seven occurrence periods P detected before that, and the deviation is calculated as the average value. The value divided by is calculated as the rate of change. Further, in the same figure, when the total number of occurrence periods P of all cylinders from the initial explosion of the engine 100 is less than 8, it is shown as a calculation based on the number less than 8. Note that the variance in statistics may be used instead of the standard deviation in the all cylinder variation rate NA. In the same figure, the behavior of the variation rate NA of all cylinders is such that the occurrence period P up to the first three times in the first cylinder 100a is different from those in the second cylinder 100b, the third cylinder 100c and the fourth cylinder 100d. Therefore, when the first three occurrence periods P are detected, the all-cylinder variation rate NA shows a behavior exceeding the determination value OV.

しかしてこのイオン電流Ｉによるプログラムの概要は、図３に示すようなものである。   The outline of the program by the ion current I is as shown in FIG.

すなわち、イオン電流Ｉを検出した後、当該イオン電流Ｉを基に発生期間Ｐを計算するステップＳ１が完了した後、ステップＳ２において、エンジン１００の初爆後のサイクル数が予め決められた基準値である８よりも少ないか否かを判定する。そして、判定したサイクル数が基準値たる所定サイクル以上であった場合にはステップＳ３へ進む。また判定したサイクル数が基準値たる所定サイクルよりも少なかった場合には、ステップＳ４へと進む。   That is, after detecting the ion current I, after step S1 for calculating the generation period P based on the ion current I is completed, in step S2, the number of cycles after the initial explosion of the engine 100 is a predetermined reference value. It is determined whether the number is less than 8. If the determined number of cycles is equal to or greater than a predetermined cycle as a reference value, the process proceeds to step S3. If the determined number of cycles is less than the predetermined cycle as the reference value, the process proceeds to step S4.

ステップＳ３では、それぞれの気筒の発生期間Ｐにより気筒別変動率Ｎを演算する。すなわち、本実施形態では第一気筒１００ａ、第二気筒１００ｂ、第三気筒１００ｃ及び第四気筒１００ｄから検出された発生期間Ｐによって、それぞれ４つの気筒別変動率Ｎが算出される。   In step S3, the cylinder specific variation rate N is calculated from the generation period P of each cylinder. That is, in this embodiment, four cylinder-specific fluctuation rates N are calculated based on the generation periods P detected from the first cylinder 100a, the second cylinder 100b, the third cylinder 100c, and the fourth cylinder 100d.

一方ステップＳ４では、全ての気筒の発生期間Ｐを基に、全気筒変動率ＮＡを演算する。   On the other hand, in step S4, the all cylinder variation rate NA is calculated based on the generation period P of all the cylinders.

ステップＳ５では、算出された気筒別変動率Ｎ或いは全気筒変動率ＮＡを基に空燃比の判定を実施する。本実施形態では、気筒別変動率Ｎ及び全気筒変動率ＮＡが判定値ＯＶよりも小さい際には燃焼状態を良好すなわち制御範囲内にある空燃比を検知したと判定する。一方、判定値ＯＶよりも大きくなる際には燃焼状態を不良すなわち制御目標値から外れた空燃比を検知したと判定する。   In step S5, the air-fuel ratio is determined based on the calculated cylinder specific variation rate N or all-cylinder variation rate NA. In the present embodiment, when the cylinder specific variation rate N and the total cylinder variation rate NA are smaller than the determination value OV, it is determined that the combustion state is good, that is, an air-fuel ratio within the control range is detected. On the other hand, when it becomes larger than the judgment value OV, it is judged that the combustion state is poor, that is, an air-fuel ratio deviating from the control target value is detected.

以上の構成において、エンジン１００を始動すると、その初爆から基準値を上回るまで基準値である所定サイクルよりも少ない７サイクルまでの間はステップＳ１、Ｓ２、Ｓ４、Ｓ５を繰り返し実行する。従って、この間は全気筒変動率ＮＡに基づいて空燃比の検知が行われる。そしてこの後時間が経過し、初爆から基準値すなわち所定サイクルである８サイクルよりも後は、ステップＳ１、Ｓ２、Ｓ３、Ｓ５を実行する。すなわち、所定サイクル以後は、継続的に気筒別変動率Ｎに基づいて空燃比の検知が行われる。   In the above configuration, when engine 100 is started, steps S1, S2, S4, and S5 are repeatedly executed from the initial explosion until 7 cycles that are less than the predetermined cycle that is the reference value until the reference value is exceeded. Accordingly, during this period, the air-fuel ratio is detected based on the all cylinder variation rate NA. Then, after this time elapses, and after the first explosion and after the reference value, that is, eight cycles which is a predetermined cycle, steps S1, S2, S3 and S5 are executed. That is, after the predetermined cycle, the air-fuel ratio is continuously detected based on the cylinder specific variation rate N.

そして、検知された空燃比に基づいて、各気筒１００ａ、１００ｂ、１００ｃ、１００ｄに配された４つの燃料噴射弁５から噴射される燃料噴射量をそれぞれ調節することによって、各気筒１００ａ、１００ｂ、１００ｃ、１００ｄ毎に空燃比の制御が行われる。   Then, based on the detected air-fuel ratio, the cylinders 100a, 100b, 100c, 100d are each adjusted by adjusting the fuel injection amounts injected from the four fuel injection valves 5 arranged in the cylinders 100a, 100b, 100c, 100d. The air-fuel ratio is controlled every 100c and 100d.

従って、本実施形態に係る内燃機関たるエンジン１００のイオン電流Ｉによる空燃比検知方法は、エンジン１００の運転が初爆から所定サイクルになるまでの間は全気筒変動率ＮＡに基づいて各気筒１００ａ、１００ｂ、１００ｃ、１００ｄの空燃比を検知し、所定サイクル以降の内燃機関の運転では気筒別変動率Ｎに基づいて各気筒１００ａ、１００ｂ、１００ｃ、１００ｄ毎に空燃比を検知するものである。つまり、エンジン１００の始動時すなわち初爆から所定サイクルに至るまでの間といった発生期間Ｐのサンプル数が少ない段階では全気筒からの発生期間Ｐをサンプリングして全気筒変動率ＮＡを算出し、この算出した全気筒変動率ＮＡを採用することにより、初爆直後から変動率の演算に要する十分量のサンプル数を得ることができるので、始動直後から正確な変動率を全気筒変動率ＮＡとして得ることができ、発生期間Ｐの変動を早いタイミングで検知して早いタイミングで空燃比の制御を行うことができる。具体的には、図２（ａ）において第一気筒１００ａの発生期間Ｐが初爆時から他の気筒よりも長いことを、直後に検出される他の気筒の発生期間Ｐをサンプリングすることにより、いち早く全気筒変動率ＮＡを通じて検出することによって制御範囲から空燃比が外れていることを検知することができる。さらに、始動直後から変動率の演算に十分な発生期間Ｐのサンプル数を得られるので、始動直後に発生期間Ｐが突発的に変動してもその影響を過度に受けてしまうことによる、誤った空燃比の検知に基づく空燃比制御を有効に回避することができる。また本実施形態では、所定サイクル以後、すなわち変動率の演算に十分なサンプル数が得られる状態となれば、気筒別変動率Ｎに切り換えて空燃比の制御を行うので、各気筒１００ａ、１００ｂ、１００ｃ、１００ｄの状態に応じた制御をそれぞれ的確に行うことができるものとなっている。   Therefore, in the air-fuel ratio detection method using the ion current I of the engine 100 as the internal combustion engine according to the present embodiment, each cylinder 100a is based on the all-cylinder variation rate NA until the operation of the engine 100 reaches a predetermined cycle from the initial explosion. , 100b, 100c, 100d are detected, and in the operation of the internal combustion engine after a predetermined cycle, the air-fuel ratio is detected for each cylinder 100a, 100b, 100c, 100d based on the variation rate N for each cylinder. That is, when the number of samples of the generation period P is small, such as when the engine 100 is started, that is, from the first explosion to a predetermined cycle, the generation period P from all cylinders is sampled to calculate the all cylinder variation rate NA. By adopting the calculated all-cylinder variation rate NA, it is possible to obtain a sufficient number of samples required for the variation rate calculation immediately after the first explosion, so that an accurate variation rate is obtained as the all-cylinder variation rate NA immediately after starting. It is possible to detect the fluctuation of the generation period P at an early timing and control the air-fuel ratio at an early timing. Specifically, in FIG. 2A, the generation period P of the first cylinder 100a is longer than that of the other cylinders since the first explosion, and the generation period P of the other cylinders detected immediately after is sampled. By quickly detecting through the all cylinder variation rate NA, it is possible to detect that the air-fuel ratio is out of the control range. Furthermore, since the number of samples of the generation period P sufficient for the calculation of the fluctuation rate can be obtained immediately after the start, even if the generation period P fluctuates immediately after the start, the influence is excessively affected. Air-fuel ratio control based on air-fuel ratio detection can be effectively avoided. Further, in the present embodiment, after a predetermined cycle, that is, when a sufficient number of samples are obtained for calculating the variation rate, the air-fuel ratio is controlled by switching to the variation rate N for each cylinder, so that each cylinder 100a, 100b, Control according to the states of 100c and 100d can be performed accurately.

なお、エンジン１００を低回転で運転している場合や負荷が低い場合など、別途設定した条件に合致した場合には、所定サイクル以後であっても全気筒変動率ＮＡを採用するようにしてもよい。気筒間のばらつきが大きい場合には、全気筒変動率ＮＡを採用する方が、的確な空燃比の制御を早く行い得る場合もあるからである。   When the engine 100 is operated at a low speed or when the load is low, when the condition set separately is met, the all-cylinder variation rate NA may be adopted even after a predetermined cycle. Good. This is because, when the variation among cylinders is large, it is sometimes possible to control the air-fuel ratio more accurately by adopting the all-cylinder variation rate NA.

さらに、上記実施形態では、エンジン１００の４つの気筒１００ａ、１００ｂ、１００ｃ、１００ｄが初爆から順次燃焼をしていく毎に全気筒変動率ＮＡの値は随時更新されるものとなっている。そこで全気筒変動率ＮＡを基に各気筒１００ａ、１００ｂ、１００ｃ、１００ｄの噴射燃料の調節を行う際に、当該全気筒変動率ＮＡの算出時に最も新しく発生期間Ｐをサンプリングした気筒に対して制御を行うようにしてもよい。言い換えれば全気筒変動率ＮＡに基づく空燃比の制御を、発生期間Ｐを最後にサンプリングした気筒に対して順次行うようにしてもよい。そうすることにより全気筒変動率ＮＡを、気筒毎の燃焼状態に対して迅速且つ有効に反映させた値として適用することができる。   Further, in the above embodiment, every time the four cylinders 100a, 100b, 100c, and 100d of the engine 100 are sequentially burned from the initial explosion, the value of the all cylinder variation rate NA is updated as needed. Therefore, when adjusting the injected fuel of each cylinder 100a, 100b, 100c, 100d based on the total cylinder variation rate NA, control is performed on the cylinder that has most recently sampled the generation period P when calculating the total cylinder variation rate NA. May be performed. In other words, the air-fuel ratio control based on the total cylinder fluctuation rate NA may be sequentially performed on the cylinders whose generation period P is sampled last. By doing so, it is possible to apply the total cylinder fluctuation rate NA as a value that reflects the combustion state of each cylinder quickly and effectively.

以上、本発明の一実施形態について説明したが、本発明は、同実施形態に限定されるものではない。例えば、上記実施形態ではイオン電流による空燃比制御について説明したが、Ｏ2センサの測定値による空燃比制御を併用することも勿論可能である。また上記実施形態において気筒別変動率並びに全気筒変動率を、標準偏差や分散を採用して演算する態様を例示したが、その他種々の統計的手法を採用することが可能である。また、基準値すなわち所定サイクル及び判定値は上記実施形態で例示した値に限定されることはなく、他の所要の値を採用することができる。その他、各部の具体的構成についても、本発明の趣旨を逸脱しない範囲で種々変形が可能である。 Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, in the above embodiment, the air-fuel ratio control by the ion current has been described, but it is of course possible to use the air-fuel ratio control by the measured value of the O 2 sensor in combination. In the above-described embodiment, the variation rate for each cylinder and the variation rate for all cylinders are calculated by using standard deviation and variance, but various other statistical methods can be employed. Further, the reference value, that is, the predetermined cycle and the determination value are not limited to the values exemplified in the above embodiment, and other required values can be adopted. In addition, the specific configuration of each part can be variously modified without departing from the spirit of the present invention.

本発明の第一実施形態おけるエンジン及び電子制御装置の概略構成を示す概略構成説明図。BRIEF DESCRIPTION OF THE DRAWINGS Schematic structure explanatory drawing which shows schematic structure of the engine and electronic control apparatus in 1st embodiment of this invention. 同実施形態の発生期間、気筒別変動率及び全気筒変動率を示すグラフ。The graph which shows the generation | occurrence | production period of the same embodiment, the change rate for every cylinder, and the change rate for all cylinders. 同実施形態の制御手順を示すフローチャート。The flowchart which shows the control procedure of the embodiment.

符号の説明Explanation of symbols

１００…内燃機関（エンジン）
１００ａ、１００ｂ、１００ｃ、１００ｄ…気筒
６…電子制御装置
７…中央演算処理装置
８…記憶装置
９…入力インターフェース
１１…出力インターフェース
Ｉ…イオン電流
Ｐ…発生期間
Ｎ…気筒別変動率
ＮＡ…全気筒変動率
ＯＶ…判定値 100: Internal combustion engine (engine)
100a, 100b, 100c, 100d ... Cylinder 6 ... Electronic control device 7 ... Central processing unit 8 ... Storage device 9 ... Input interface 11 ... Output interface I ... Ion current P ... Generation period N ... Variation rate for each cylinder NA ... All cylinders Fluctuation rate OV ... judgment value

Claims (1)

多気筒の内燃機関におけるそれぞれの気筒の燃焼室内に発生するイオン電流を検出し、検出したイオン電流の発生している発生期間を計測し、当該発生期間を基に演算した各気筒における変動率に基づいて各気筒の空燃比を検知し得るものであって、
少なくとも内燃機関の運転が初爆から所定サイクルになるまでの間は、計測した全気筒における発生期間を基に算出された全気筒変動率に基づいて各気筒の空燃比を検知する内燃機関のイオン電流による空燃比検知方法。 In a multi-cylinder internal combustion engine, the ion current generated in the combustion chamber of each cylinder is detected, the generation period during which the detected ion current is generated is measured, and the variation rate in each cylinder calculated based on the generation period is calculated. The air-fuel ratio of each cylinder can be detected based on
Ion of the internal combustion engine that detects the air-fuel ratio of each cylinder based on the variation rate of all cylinders calculated based on the measured occurrence period in all cylinders at least until the operation of the internal combustion engine reaches the predetermined cycle An air-fuel ratio detection method using electric current.
JP2006028126A 2006-02-06 2006-02-06 Air-fuel ratio detection method using ion current of internal combustion engine Expired - Fee Related JP4592612B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006028126A JP4592612B2 (en) 2006-02-06 2006-02-06 Air-fuel ratio detection method using ion current of internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006028126A JP4592612B2 (en) 2006-02-06 2006-02-06 Air-fuel ratio detection method using ion current of internal combustion engine

Publications (2)

Publication Number Publication Date
JP2007205321A true JP2007205321A (en) 2007-08-16
JP4592612B2 JP4592612B2 (en) 2010-12-01

Family

ID=38484985

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006028126A Expired - Fee Related JP4592612B2 (en) 2006-02-06 2006-02-06 Air-fuel ratio detection method using ion current of internal combustion engine

Country Status (1)

Country Link
JP (1) JP4592612B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013205262A (en) * 2012-03-29 2013-10-07 Daihatsu Motor Co Ltd Control device for internal combustion engine

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0534244A (en) * 1991-08-01 1993-02-09 Hitachi Ltd Combustion state detector of internal combustion engine
JPH08261047A (en) * 1995-03-27 1996-10-08 Daihatsu Motor Co Ltd Lean limit sensing method
JPH10176594A (en) * 1996-12-18 1998-06-30 Daihatsu Motor Co Ltd Combustion fluctuation detecting method for internal combustion engine
JP2000045846A (en) * 1998-07-30 2000-02-15 Toyota Motor Corp Fuel injection quantity control device for internal combustion engine
JP2000054942A (en) * 1998-08-07 2000-02-22 Toyota Motor Corp Air-fuel ratio control device for internal combustion engine
JP3150429B2 (en) * 1992-07-21 2001-03-26 ダイハツ工業株式会社 Lean limit detection method using ion current

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0534244A (en) * 1991-08-01 1993-02-09 Hitachi Ltd Combustion state detector of internal combustion engine
JP3150429B2 (en) * 1992-07-21 2001-03-26 ダイハツ工業株式会社 Lean limit detection method using ion current
JPH08261047A (en) * 1995-03-27 1996-10-08 Daihatsu Motor Co Ltd Lean limit sensing method
JPH10176594A (en) * 1996-12-18 1998-06-30 Daihatsu Motor Co Ltd Combustion fluctuation detecting method for internal combustion engine
JP2000045846A (en) * 1998-07-30 2000-02-15 Toyota Motor Corp Fuel injection quantity control device for internal combustion engine
JP2000054942A (en) * 1998-08-07 2000-02-22 Toyota Motor Corp Air-fuel ratio control device for internal combustion engine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013205262A (en) * 2012-03-29 2013-10-07 Daihatsu Motor Co Ltd Control device for internal combustion engine

Also Published As

Publication number Publication date
JP4592612B2 (en) 2010-12-01

Similar Documents

Publication Publication Date Title
US7448253B2 (en) Combustion state determination method of internal combustion engine
JP4799200B2 (en) Operation control method based on ion current of internal combustion engine
JP4721907B2 (en) Air-fuel ratio determination method for internal combustion engine based on ion current
JP4619299B2 (en) Method for determining the combustion state of an internal combustion engine
JP4592612B2 (en) Air-fuel ratio detection method using ion current of internal combustion engine
JP5022347B2 (en) Misfire detection method for internal combustion engine
JP2007138802A (en) Combustion condition detection device for internal combustion engine
JP2007182845A (en) Air-fuel ratio-determining method for internal combustion engine based on ion current
JP2004232568A (en) Method of determining combustion state of internal combustion engine
JP4381253B2 (en) Combustion state detection method for internal combustion engine
JP3234418B2 (en) Lean limit detection method
JP2007182844A (en) Determining method for ion current detection system of internal combustion engine
JP3234419B2 (en) Lean limit detection method
JP4749171B2 (en) Air-fuel ratio determination method for internal combustion engine based on ion current
JP4443522B2 (en) Method for determining lean combustion of an internal combustion engine
JP4293939B2 (en) Control method for internal combustion engine
JP5009843B2 (en) Method for determining the combustion state of an internal combustion engine
JP5009844B2 (en) Method for determining the combustion state of an internal combustion engine
JPH10176595A (en) Measuring method for combustion period in internal combustion engine
GB2447177A (en) Air-fuel ratio judging method of internal combustion engine based on ion current
JPH09228940A (en) Combustion time measuring method

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20080528

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20091225

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20100112

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100302

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20100914

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20100914

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130924

Year of fee payment: 3

R150 Certificate of patent or registration of utility model

Ref document number: 4592612

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees