JP2007139397A - Glow plug with combustion pressure sensor - Google Patents
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- JP2007139397A JP2007139397A JP2005337915A JP2005337915A JP2007139397A JP 2007139397 A JP2007139397 A JP 2007139397A JP 2005337915 A JP2005337915 A JP 2005337915A JP 2005337915 A JP2005337915 A JP 2005337915A JP 2007139397 A JP2007139397 A JP 2007139397A
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Abstract
Description
本発明は、ディーゼルエンジン等の内燃機関の始動補助装置として使用すると共に、内燃機関の燃焼圧の変化を検知することができる燃焼圧検知機能付きグロープラグに関するものである。 The present invention relates to a glow plug with a combustion pressure detection function that can be used as an auxiliary start device for an internal combustion engine such as a diesel engine and can detect a change in combustion pressure of the internal combustion engine.
この種の燃焼圧センサ付きグロープラグとしては、例えば特開2004−278934号公報に記載の燃焼圧検知機能付きグロープラグが提案されている。これは、プラグケースとこの内側に保持されたグロープラグ本体と燃焼圧検知機構とを備え、グロープラグ本体は、ハウジング、シース部材、ヒータ部材、及び中軸を備える。燃焼圧検知機構は、内燃機関の燃焼圧の変化によって、グロープラグ本体のハウジングや中軸に生じる軸線方向の変位を電気信号に変換する圧電素子を含み、圧電素子は、プラグケースの内方突出部と中軸の外方突出部との間に挟持され、プラグケースのケース基端部と中軸6との間に形成されている。 As this type of glow plug with a combustion pressure sensor, for example, a glow plug with a combustion pressure detection function described in JP-A-2004-278934 has been proposed. This includes a plug case, a glow plug main body held inside the plug case, and a combustion pressure detecting mechanism, and the glow plug main body includes a housing, a sheath member, a heater member, and a central shaft. The combustion pressure detection mechanism includes a piezoelectric element that converts an axial displacement generated in the housing and the middle shaft of the glow plug body into an electric signal due to a change in the combustion pressure of the internal combustion engine, and the piezoelectric element is an inward protruding portion of the plug case. Is formed between the case base end portion of the plug case and the middle shaft 6.
また、例えば実開平4−57056号公報公報に記載の着火センサ付グロープラグにおいては、圧電素子をシース側に押圧する為の弾性部材が圧電素子と支持体(ブッシュ)との間に弾性部材(スプリング)が介装されている。 For example, in the glow plug with an ignition sensor described in Japanese Utility Model Publication No. 4-57056, an elastic member for pressing the piezoelectric element toward the sheath is an elastic member (bush) between the piezoelectric element and the support (bush). Spring) is installed.
さらに、例えば特開2002−327919号公報や特開2004−124911号公報に記載の燃焼圧センサ付グロープラグにおいては、圧電素子が圧力伝達部と支持部との何れも剛体により挟持されたものが提案されている。
解決しようとする問題点は、例えば上記の特許文献2から特許文献4に開示の従来技術おいては、ハウジングとパイプ部材が固定され、さらにハウジングの弾性力を利用して微小変形する為に拘束力が大きくなる事や、圧電素子が剛体と剛体に直接挟まれ、与圧調整バネもないので、グロープラグの締め付けやハウジングおよび内部部品の熱膨張により与圧が変化し易くなる。その結果検出しようとする燃焼圧力に対する燃焼圧センサの出力が小さくなり、S/N比が大きいという問題があった。 The problem to be solved is that, for example, in the prior art disclosed in Patent Document 2 to Patent Document 4 described above, the housing and the pipe member are fixed and further restrained because they are deformed minutely using the elastic force of the housing. Since the force is increased, the piezoelectric element is directly sandwiched between the rigid bodies and there is no pressurizing adjustment spring, the pressurization is likely to change due to the tightening of the glow plug and the thermal expansion of the housing and internal components. As a result, there is a problem that the output of the combustion pressure sensor with respect to the combustion pressure to be detected becomes small and the S / N ratio is large.
また、上記の特許文献1に開示の従来技術においては、圧電素子の支持体にバネが含まれている為、燃焼圧力の伝達が遅延するという問題があった。 Further, the conventional technique disclosed in Patent Document 1 has a problem in that the transmission of combustion pressure is delayed because the support of the piezoelectric element includes a spring.
さらに、上記の特許文献2から特許文献4に開示の従来技術においては、圧電素子をグロープラグの取り付けネジ近傍に配置する為、圧力伝達体の長さが長くなり、特に圧力伝達媒体がシース管と電極棒との複数部品に及び質量が大きくなる為、振動や加速度感度が増加し、燃焼圧センサのS/N比が大きかったり、燃焼圧力の伝達遅延を生じるという問題があった。 Further, in the prior art disclosed in Patent Document 2 to Patent Document 4 described above, since the piezoelectric element is arranged in the vicinity of the mounting screw of the glow plug, the length of the pressure transmission body becomes long. As a result, the vibration and acceleration sensitivity are increased, the S / N ratio of the combustion pressure sensor is large, and the combustion pressure is delayed.
本発明は、一端側が内燃機関の燃焼室側に位置するように前記内燃機関に取り付けられる筒状のハウジングと、前記ハウジングの前記一端側から露出するように前記ハウジングの内部に保持されると共に、前記一端側が前記燃焼室内に露出したシース管と、前記シース管内に設けられ、通電により発熱する発熱体と、一部が前記ハウジングの他端から突出するように前記ハウジング内に収納されると共に、前記発熱体と電気的に導通された金属製の電極棒と、前記内燃機関の燃焼圧の発生に伴い前記シース管に作用する力が伝達されることにより、前記燃焼圧を検出する圧電素子よりなる燃焼圧センサとを備えた、燃焼圧センサ付きグロープラグにおいて、
前記圧電素子は、前記ハウジングの内部に保持された前記シース管の端部と前記電極棒の燃焼室側端部とに挟まれた空間部に配置され、前記内燃機関の燃焼圧の発生に伴い、前記シース管から略直接的に前記圧電素子へ伝達されることを特徴とする。
The present invention has a cylindrical housing attached to the internal combustion engine so that one end side is located on the combustion chamber side of the internal combustion engine, and is held inside the housing so as to be exposed from the one end side of the housing, A sheath tube having one end exposed in the combustion chamber; a heating element provided in the sheath tube that generates heat when energized; and a portion that is housed in the housing so as to protrude from the other end of the housing; From a metal electrode rod that is electrically connected to the heating element and a piezoelectric element that detects the combustion pressure by transmitting a force acting on the sheath tube as the combustion pressure of the internal combustion engine is generated. In a glow plug with a combustion pressure sensor, comprising a combustion pressure sensor
The piezoelectric element is disposed in a space portion sandwiched between an end portion of the sheath tube held inside the housing and an end portion on the combustion chamber side of the electrode rod, and accompanying the generation of combustion pressure of the internal combustion engine , Being transmitted from the sheath tube almost directly to the piezoelectric element.
本発明の前記ハウジングは、前記燃焼室側に配置されるフロントハウジングと前記内燃機関に取り付けられるリアハウジングとの二体からなり、前記燃焼圧センサは、前記フロントハウジングと前記リアハウジングとに挟まれた空間部に配置されていることを特徴とする。 The housing of the present invention comprises two bodies, a front housing disposed on the combustion chamber side and a rear housing attached to the internal combustion engine, and the combustion pressure sensor is sandwiched between the front housing and the rear housing. It is arrange | positioned in the open space part.
本発明の前記圧電素子は、前記ハウジングの内部に保持された前記シース管の段部内側と前記ハウジングの内径段部との間に収納された与圧バネにより前記シース管を介して規定の圧力が印加されていること特徴とする。 The piezoelectric element of the present invention has a predetermined pressure through the sheath tube by a pressurizing spring housed between the inside of the step portion of the sheath tube held inside the housing and the inner diameter step portion of the housing. Is applied.
本発明の前記圧電素子の材料は、ランガサイト系結晶としたこと特徴とする。 The material of the piezoelectric element of the present invention is a langasite crystal.
本発明は、前記ハウジングの他端近傍の外周面に締付部が形成され、前記締付部は内周側に収納部を有し、前記収納部に前記燃焼圧センサからの電気信号を変換及び増幅するアンプが収納されていることを特徴とする。 In the present invention, a tightening portion is formed on an outer peripheral surface near the other end of the housing, the tightening portion has a storage portion on an inner peripheral side, and an electric signal from the combustion pressure sensor is converted into the storage portion. And an amplifier to be amplified is housed.
本発明は、前記ハウジングの内径面と前記シース管の外径面との接触部の隙間はシール部材により柔軟且つ気密に保持されていること特徴とする。 The present invention is characterized in that the clearance between the inner diameter surface of the housing and the outer diameter surface of the sheath tube is held flexible and airtight by a seal member.
本発明の燃焼圧センサ付きグロープラグは、圧電素子をグロープラグの取り付けネジより前側に設置したので、圧力伝達体の長さを短く軽量化でき、また圧力伝達媒体がシース管のみであるから、振動、加速度による燃焼圧センサの出力変動を軽減して、燃焼圧力の伝達の遅れも軽減できる。 In the glow plug with a combustion pressure sensor of the present invention, since the piezoelectric element is installed on the front side of the mounting screw of the glow plug, the length of the pressure transmission body can be shortened and reduced in weight, and the pressure transmission medium is only a sheath tube. The fluctuation in the output of the combustion pressure sensor due to vibration and acceleration can be reduced, and the delay in the transmission of the combustion pressure can also be reduced.
また、与圧バネが燃焼圧力の伝達経路に含まれない(圧力伝達方向に対して与圧バネと圧電素子が力学的に並列)構成なので、燃焼圧力の遅延が無く、グロープラグの締め付けやハウジングおよび内部部品の熱膨張等による与圧の変化が軽減されると共に、ハウジングの内径面とシース管の外径面との接触部の隙間がシール部材により柔軟且つ気密に保持されていることにより、燃焼圧力伝達軸方向の拘束力を小さくできるので、感度が向上し且つ振動や熱膨張による燃焼圧出力の変動を受け難くなり、燃焼圧力の伝達精度が安定して、S/N比が向上する。 In addition, since the pressurized spring is not included in the combustion pressure transmission path (the pressurized spring and the piezoelectric element are mechanically parallel to the pressure transmission direction), there is no delay in combustion pressure, glow plug tightening and housing And the change in the pressurization due to the thermal expansion of the internal parts is reduced, and the clearance between the inner diameter surface of the housing and the outer diameter surface of the sheath tube is held flexibly and airtightly by the seal member. Since the restraint force in the combustion pressure transmission axis direction can be reduced, the sensitivity is improved and the combustion pressure output is less susceptible to fluctuations due to vibration and thermal expansion, the combustion pressure transmission accuracy is stabilized, and the S / N ratio is improved. .
また、圧電素子をグロープラグの取付部より前側に設置したので、ハウジングの他端近傍の外周面形成した締付部の内周側に収納部を形成し、その収納部に前記燃焼圧センサからの電気信号を変換及び増幅するアンプを収納したことにより、ユニットとしての小型化が可能となった。 Further, since the piezoelectric element is installed in front of the glow plug mounting portion, a storage portion is formed on the inner peripheral side of the tightening portion formed on the outer peripheral surface near the other end of the housing, and the combustion pressure sensor is connected to the storage portion. By storing an amplifier that converts and amplifies the electrical signal, the unit can be miniaturized.
さらに、従来の燃焼圧センサ付きグロープラグよりも圧電素子がより燃焼室側に近くなる事により、より高い耐熱性を要求されるが、キューリー点が1200℃以上と高いランガサイト系結晶を用いる事により支障なく使用可能とする事が出来る。 Furthermore, the piezoelectric element is closer to the combustion chamber side than the conventional glow plug with a combustion pressure sensor, so higher heat resistance is required. However, a Langasite crystal having a high Curie point of 1200 ° C. or higher should be used. Can be used without any problem.
図1は、本発明の燃焼圧センサ付きグロープラグの全体縦断面図である。一端側が内燃機関の燃焼室側に位置するように内燃機関に取り付けられる筒状のハウジング(1)と、ハウジングの一端側から露出するようにハウジングの内部に保持されると共に、一端側が前記燃焼室内に露出したシース管(2)と、シース管内に設けられ、通電により発熱する発熱体(3)と、一部がハウジングの他端から突出するようにハウジング内に収納されると共に、発熱体と電気的に導通された金属製の電極棒(4)と、内燃機関の燃焼圧の発生に伴いシース管に作用する力が伝達されることにより、燃焼圧を検出する圧電素子(5)よりなる燃焼圧センサ(6)とを備えた、燃焼圧センサ付きグロープラグであって、圧電素子は、ハウジングの内部に保持さたシース管の端部と電極棒の燃焼室側端部とに挟まれた空間部に配置され、前記内燃機関の燃焼圧の発生に伴い、シース管から略直接的に圧電素子へ伝達される。 FIG. 1 is an overall longitudinal sectional view of a glow plug with a combustion pressure sensor of the present invention. A cylindrical housing (1) attached to the internal combustion engine so that one end side is positioned on the combustion chamber side of the internal combustion engine, and held inside the housing so as to be exposed from one end side of the housing, and one end side is the combustion chamber An exposed sheath tube (2), a heating element (3) provided in the sheath tube and generating heat when energized, and being housed in the housing so that a part protrudes from the other end of the housing, It consists of an electrically conductive metal electrode rod (4) and a piezoelectric element (5) for detecting the combustion pressure by transmitting the force acting on the sheath tube as the combustion pressure of the internal combustion engine is generated. A glow plug with a combustion pressure sensor comprising a combustion pressure sensor (6), wherein the piezoelectric element is sandwiched between the end of the sheath tube held inside the housing and the end of the electrode rod on the combustion chamber side Placed in an open space It is, with the generation of combustion pressure of the internal combustion engine is substantially transmitted directly to the piezoelectric element from the sheath tube.
また、この実施例では、ハウジング(1)は、燃焼室側に配置されるフロントハウジング(7)と内燃機関に取り付けられるリアハウジング(8)との二体からなっており、燃焼圧センサは、フロントハウジングとリアハウジングとに挟まれた空間部に配置されている。しかしながら、勿論ハウジングを一体としても良く、さらに燃焼圧センサの組込の容易さに応じて三体以上の複数体にしても良い。 In this embodiment, the housing (1) is composed of two bodies, a front housing (7) disposed on the combustion chamber side and a rear housing (8) attached to the internal combustion engine. It arrange | positions in the space part pinched | interposed by the front housing and the rear housing. However, of course, the housing may be integrated, and more than two bodies may be provided depending on the ease of incorporation of the combustion pressure sensor.
圧電素子(5)は、ハウジング(1)の内部に保持されたシース管(2)の段部内側とハウジングの内径段部との間に収納された与圧バネ(9)によりシース管を介して規定の圧力が印加されており、材料は、ランガサイト、ランガテイト、ランガナイト等のランガサイト系結晶を用いている。 The piezoelectric element (5) is passed through the sheath tube by a pressurizing spring (9) housed between the stepped inner side of the sheath tube (2) held inside the housing (1) and the inner diameter stepped portion of the housing. A specified pressure is applied, and the material used is a langasite crystal such as langasite, langate, langanite.
さらに、ハウジング(1)の他端近傍の外周面に締付部(10)が形成され、締付部は内周側に収納部(11)を有し、収納部に燃焼圧センサ(6)からの電気信号を変換及び増幅するアンプ(12)が収納されており、ハウジングの内径面と前記シース管(2)の外径面との接触部の隙間は、例えば10μm〜100μmの金属箔例えばインコネルや析出硬化型のSUSなどを用いるシール部材(13)により柔軟且つ気密に保持されている。 Further, a tightening portion (10) is formed on the outer peripheral surface in the vicinity of the other end of the housing (1), the tightening portion has a storage portion (11) on the inner peripheral side, and the combustion pressure sensor (6) in the storage portion. An amplifier (12) that converts and amplifies an electrical signal from the housing is housed, and a gap between the contact portion between the inner diameter surface of the housing and the outer diameter surface of the sheath tube (2) is, for example, a metal foil of 10 μm to 100 μm, for example It is held in a flexible and airtight manner by a seal member (13) using inconel, precipitation hardening type SUS, or the like.
1 ハウジング
2 シース管
3 発熱体
4 電極棒
5 圧電素子
6 燃焼圧センサ
7 フロントハウジング
8 リアハウジング
9 与圧バネ
10 締付部
11 収納部
12 アンプ
13 シール部材
14 絶縁スリーブ
15 リング
16 スリーブ
17 バネ
18 蓋
19 ゴムワッシャー
20 絶縁リング
21 ナット
22 電極膜
23 金属箔
24 テーパリング
DESCRIPTION OF SYMBOLS 1 Housing 2 Sheath tube 3 Heating element 4 Electrode rod 5 Piezoelectric element 6 Combustion pressure sensor 7 Front housing 8 Rear housing 9 Pressurizing spring 10 Tightening part 11 Storage part 12 Amplifier 13 Sealing member 14 Insulating sleeve 15 Ring 16 Sleeve 17 Spring 18 Lid 19 Rubber washer 20 Insulating ring 21 Nut 22 Electrode film 23 Metal foil 24 Tapered ring
Claims (6)
前記圧電素子は、前記ハウジングの内部に保持された前記シース管の端部と前記電極棒の燃焼室側端部とに挟まれた空間部に配置され、前記内燃機関の燃焼圧の発生に伴い、前記シース管から略直接的に前記圧電素子へ伝達されることを特徴とする燃焼圧センサ付きグロープラグ。 A cylindrical housing (1) attached to the internal combustion engine so that one end side is located on the combustion chamber side of the internal combustion engine, and held inside the housing so as to be exposed from the one end side of the housing, A sheath tube (2) having one end exposed in the combustion chamber, a heating element (3) provided in the sheath tube and generating heat when energized, and a part projecting from the other end of the housing. The metal electrode rod (4) that is housed and electrically connected to the heating element, and the force acting on the sheath tube with the generation of the combustion pressure of the internal combustion engine is transmitted. In a glow plug with a combustion pressure sensor, comprising a combustion pressure sensor (6) comprising a piezoelectric element (5) for detecting the combustion pressure,
The piezoelectric element is disposed in a space portion sandwiched between an end portion of the sheath tube held inside the housing and an end portion on the combustion chamber side of the electrode rod, and accompanying the generation of combustion pressure of the internal combustion engine A glow plug with a combustion pressure sensor, wherein the glow plug is transmitted almost directly from the sheath tube to the piezoelectric element.
The gap between the contact portions between the inner diameter surface of the housing (1) and the outer diameter surface of the sheath tube (2) is held in a flexible and airtight manner by the seal member (13). 5. A glow plug with a combustion pressure sensor according to 5.
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JP2005337915A JP2007139397A (en) | 2005-11-23 | 2005-11-23 | Glow plug with combustion pressure sensor |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009243710A (en) * | 2008-03-28 | 2009-10-22 | Ngk Spark Plug Co Ltd | Glow plug |
JP2010190445A (en) * | 2009-02-16 | 2010-09-02 | Mikuni Corp | Glow plug including combustion pressure sensor |
JP2013117375A (en) * | 2013-03-21 | 2013-06-13 | Ngk Spark Plug Co Ltd | Glow plug |
RU2485401C2 (en) * | 2008-02-13 | 2013-06-20 | БоргВарнер БЕРУ Системс ГмбХ | Ignition plug capable of pressure measurement |
-
2005
- 2005-11-23 JP JP2005337915A patent/JP2007139397A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2485401C2 (en) * | 2008-02-13 | 2013-06-20 | БоргВарнер БЕРУ Системс ГмбХ | Ignition plug capable of pressure measurement |
JP2009243710A (en) * | 2008-03-28 | 2009-10-22 | Ngk Spark Plug Co Ltd | Glow plug |
JP2010190445A (en) * | 2009-02-16 | 2010-09-02 | Mikuni Corp | Glow plug including combustion pressure sensor |
JP2013117375A (en) * | 2013-03-21 | 2013-06-13 | Ngk Spark Plug Co Ltd | Glow plug |
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