JPS63225130A - Knock sensor - Google Patents
Knock sensorInfo
- Publication number
- JPS63225130A JPS63225130A JP5897487A JP5897487A JPS63225130A JP S63225130 A JPS63225130 A JP S63225130A JP 5897487 A JP5897487 A JP 5897487A JP 5897487 A JP5897487 A JP 5897487A JP S63225130 A JPS63225130 A JP S63225130A
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric element
- engine
- knocking
- shape memory
- temperature
- 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
Links
- 229910001285 shape-memory alloy Inorganic materials 0.000 claims abstract description 19
- 230000004044 response Effects 0.000 claims description 5
- 230000035945 sensitivity Effects 0.000 abstract description 7
- 238000001514 detection method Methods 0.000 abstract 1
- 229910004337 Ti-Ni Inorganic materials 0.000 description 1
- 229910011209 Ti—Ni Inorganic materials 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- KHYBPSFKEHXSLX-UHFFFAOYSA-N iminotitanium Chemical compound [Ti]=N KHYBPSFKEHXSLX-UHFFFAOYSA-N 0.000 description 1
- 230000006903 response to temperature Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L23/00—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid
- G01L23/22—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
- G01L23/221—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines for detecting or indicating knocks in internal combustion engines
- G01L23/222—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines for detecting or indicating knocks in internal combustion engines using piezoelectric devices
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、エンジンの振動からノッキングを検出して、
点火時期を制御するノックセンサに関するものである。Detailed Description of the Invention (Industrial Application Field) The present invention detects knocking from engine vibration,
This invention relates to a knock sensor that controls ignition timing.
（従来の技術）
自動車等のエンジンがノッキングを起こすと、エンジン
のノッキング特有の振動が発生する。この振動をノック
センサで検出し、センサ出力を計測することによりエン
ジンのノッキングを検知できる。(Prior Art) When the engine of an automobile or the like causes knocking, vibrations peculiar to engine knocking are generated. Engine knocking can be detected by detecting this vibration with a knock sensor and measuring the sensor output.
従来のノックセンサを第３図及び第４図により説明する
。第３図（ａ）は従来のノックセンサの側面図、第３図
（ｂ）は同斜視図、第４図はノッキングの特徴周波数と
エンジン温度との関係を示すグラフである。同図におい
て、１１はバイモルフ型圧電素子、１２は筐体、１３は
おさえ板、１４はビス、１５は電気出力端子、１６は取
付部である。圧電素子１１は、それとおさえ板１３のそ
れぞれの長手方向を直交させるようにして、おさえ板１
３と筐体１２との間にその一端が挟持され、おさえ板１
３の一端をビス１４により筐体１２にとめることにより
固定されている、取付部１６はノックセンサをエンジン
に取り付けるためのものである。A conventional knock sensor will be explained with reference to FIGS. 3 and 4. FIG. 3(a) is a side view of a conventional knock sensor, FIG. 3(b) is a perspective view thereof, and FIG. 4 is a graph showing the relationship between the characteristic frequency of knocking and engine temperature. In the figure, 11 is a bimorph type piezoelectric element, 12 is a housing, 13 is a holding plate, 14 is a screw, 15 is an electric output terminal, and 16 is a mounting portion. The piezoelectric element 11 is attached to the presser plate 1 so that the longitudinal direction of the piezoelectric element 11 and the presser plate 13 are orthogonal to each other.
3 and the housing 12, one end of which is held between the holding plate 1 and the housing 12.
A mounting portion 16, which is fixed by fastening one end of the knock sensor 3 to the housing 12 with a screw 14, is for mounting the knock sensor to the engine.
このノックセンサは、圧電素子１１をその一端で支える
片持ちぼり構造を有し、圧電素子１１は筐体１２から伝
わる振動に応じて振動し、その振動による外力に応じた
電気出力を得ることができる。This knock sensor has a cantilever structure that supports a piezoelectric element 11 at one end, and the piezoelectric element 11 vibrates in response to vibrations transmitted from the housing 12, and can obtain an electrical output in accordance with the external force caused by the vibration. can.
このときの電気出力は、圧電素子１１が筐体１２から伝
わる振動によって共振を起こす共振周波数のところで最
大となる。即ち、ノックセンサの感度が最大となる。圧
電素子１１の共振周波数ｆ０は、で与えられる。ここで
、ｔは圧電素子の厚さ、Ｑは圧電素子のおさえ板１３と
筐体１２との挟持端（以後、固定端という）から先端ま
での突出している長さ、Ｅは圧電素子のヤング率、ρは
圧電素子の密度を示す、そこで、従来のノックセンサは
、圧電素子１１の共振周波数ｆ０をエンジンから発生す
るノッキング時の振動周波数ｆｋに一致させる、即ちｆ
０＝ｆｋになるように、圧電素子１１の厚さ。The electrical output at this time becomes maximum at a resonant frequency where the piezoelectric element 11 resonates due to vibrations transmitted from the housing 12. That is, the sensitivity of the knock sensor becomes maximum. The resonance frequency f0 of the piezoelectric element 11 is given by: Here, t is the thickness of the piezoelectric element, Q is the protruding length from the clamping end (hereinafter referred to as fixed end) of the piezoelectric element between the holding plate 13 and the housing 12 to the tip, and E is the young of the piezoelectric element. The ratio, ρ, indicates the density of the piezoelectric element.Therefore, in the conventional knock sensor, the resonant frequency f0 of the piezoelectric element 11 is made to match the vibration frequency fk during knocking generated from the engine, that is, f
The thickness of the piezoelectric element 11 is set so that 0=fk.
長さを定めて設計製作され、これをエンジンのシリング
に近い゛壁面に固定し、ノッキング時の振動を検出して
いた。It was designed and manufactured to a specific length and was fixed to a wall near the engine sill to detect vibrations during knocking.
（発明が解決しようとする問題点）
しかし、上記従来のノックセンサでは、圧電素子の共振
周波数ｆ０を、特定の条件における１つのノッキング時
の振動周波数ｆｋに一致させているので、ｆｏは固定値
になっている。(Problem to be Solved by the Invention) However, in the conventional knock sensor described above, the resonant frequency f0 of the piezoelectric element is made to match the vibration frequency fk during one knocking under specific conditions, so fo is a fixed value. It has become.
実際のエンジンから発生するノッキング時の周波数につ
いては、エンジン自体の温度が低温から高温になるにつ
れて、ノッキングの特徴周波数ｆ、は第４図に示すよう
に変化する。即ち、低温時のノッキング特徴周波数をｆ
ｈＬ６ｖ、高温時のノッキング特徴周波数をｆｈｌｌ
ｌ、、とすれば、ｆ□ｌＪｈ＞ ｆ ｈＬｏｗ
の関係となる。Regarding the frequency of knocking occurring in an actual engine, the characteristic frequency f of knocking changes as shown in FIG. 4 as the temperature of the engine itself goes from low to high. That is, the knocking characteristic frequency at low temperature is f
hL6v, fhlll knocking characteristic frequency at high temperature
l, , then there is a relationship f□lJh>f hLow.
このため、従来のセンサでは、圧電素子の共振周波数を
ある特定の温度条件でのエンジンから発生するノッキン
グ周波数に一致させることはできるが、すべての温度範
囲のノッキング特徴周波数に一致させることができない
ため、全温度範囲で生じるノッキングについてＳ／Ｈの
高い測定ができないという問題があった。For this reason, with conventional sensors, although it is possible to match the resonant frequency of the piezoelectric element to the knocking frequency generated by the engine under certain temperature conditions, it is not possible to match the knocking characteristic frequency over the entire temperature range. However, there was a problem in that high S/H could not be measured for knocking that occurs over the entire temperature range.
本発明は、エンジンの全温度範囲で生じるノッキングを
高感度で検出できるノックセンサを提供するものである
。The present invention provides a knock sensor that can detect knocking occurring in the entire engine temperature range with high sensitivity.
（問題点を解決するための手段）
本発明は、上記問題点を解決するために、振動を検知し
て電気出力を得る圧電素子の一端を、温度変化に応じて
形状を変化させる形状記憶合金でそれぞれの長手方向が
相互に直交するように挟持し、さらにそれらをおさえ板
と筐体との間に、前記圧電素子と前記おさえ板のそれぞ
れの長手方向が相互に直交するようにして挟み込み、前
記おさえ板の一端を前記筐体に固定し、前記形状記憶合
金の形状をエンジン温度変化に応じて変化させるのに伴
って、前記圧電素子の前記形状記憶合金による挟持端か
ら先までの突出長を変化させることにより、前記圧電素
子の前記エンジン温度変化に応じる共振周波数の変動を
、前記エンジン温度変化範囲で生じるノッキングの特徴
周波数の変動に一致させるものである。(Means for Solving the Problems) In order to solve the above problems, the present invention provides that one end of a piezoelectric element that detects vibrations and obtains an electrical output is made of a shape memory alloy that changes shape in accordance with temperature changes. sandwiching the piezoelectric element and the press plate so that their respective longitudinal directions are orthogonal to each other, and further sandwiching them between a holding plate and a housing so that their respective longitudinal directions are perpendicular to each other, One end of the presser plate is fixed to the casing, and as the shape of the shape memory alloy changes in accordance with changes in engine temperature, the protrusion length of the piezoelectric element from the end held by the shape memory alloy to the tip. By changing , the variation in the resonant frequency of the piezoelectric element in response to the engine temperature change is made to match the variation in the characteristic frequency of knocking that occurs in the engine temperature change range.
（作 用）
本発明は、上記構成により、圧電素子を上下から挟持し
ている形状記憶合金がエンジン温度の変化に応じて形状
を変えるために、その変化に伴って挟持されている圧電
素子の固定端から先端までの長さも変化する。この長さ
の変化により、圧電素子の共振周波数の変動がノッキン
グの特徴周波数の変動に全く一致するので、変化するエ
ンジン温度の全範囲で生じるノッキングのすべてに対し
最大感度で検出できることになる。(Function) With the above configuration, the shape memory alloy that holds the piezoelectric element between the top and bottom changes its shape in response to changes in engine temperature, so that the shape of the piezoelectric element that is held between the top and bottom changes as the shape changes. The length from the fixed end to the tip also varies. This length variation ensures that the variation in the resonant frequency of the piezoelectric element exactly matches the variation in the characteristic frequency of knocking, so that it can be detected with maximum sensitivity for all knocking occurring over the entire range of varying engine temperatures.
（実施例） 本発明の一実施例を第１図及び第２図により説明する。(Example) An embodiment of the present invention will be described with reference to FIGS. 1 and 2.
第１図（ａ）は本発明の一実施例のノッキングセンサの
側面図、第１図（ｂ）は同実施例の斜視図、第２図（ａ
）は同実施例の形状記憶合金の長さとエンジン温度との
関係を示すグラフ、第２図（ｂ）は同実施例のノックセ
ンサの圧電素子の共振周波数とエンジン温度との関係を
示すグラフである。同図において、１はバイモルフ型圧
電素子、２は筐体、３はおさえ板、４はビス、５は電気
出力端子、６は取付部、７は形状記憶合金、０は圧電素
子１の固定端から先端までの長さ、ｔは圧電素子の厚さ
である。FIG. 1(a) is a side view of a knocking sensor according to an embodiment of the present invention, FIG. 1(b) is a perspective view of the same embodiment, and FIG.
) is a graph showing the relationship between the length of the shape memory alloy and the engine temperature in the same example, and FIG. 2(b) is a graph showing the relationship between the resonance frequency of the piezoelectric element of the knock sensor in the same example and the engine temperature. be. In the figure, 1 is a bimorph type piezoelectric element, 2 is a housing, 3 is a holding plate, 4 is a screw, 5 is an electric output terminal, 6 is a mounting part, 7 is a shape memory alloy, 0 is a fixed end of the piezoelectric element 1 The length from to the tip, t is the thickness of the piezoelectric element.
圧電素子１の一端は、例えばＴｉ−Ｎｉ系の形状記憶合
金７によってそれぞれの長手方向が相互に直交するよう
に挟持され、さらに、それらの圧電素子１と２枚の形状
記憶合金７は、おさえ板３と筐体２との間に圧電素子１
とおさえ板３のそれぞれの長手方向が直交するように挟
み込まれ、おさえ板３の一端をビス４で筐体２にとめる
ことにより固定されている。取付部６はノックセンサを
エンジン側面に取り付けるためのものである。One end of the piezoelectric element 1 is held between, for example, Ti-Ni-based shape memory alloys 7 such that their respective longitudinal directions are perpendicular to each other, and the piezoelectric element 1 and the two shape memory alloys 7 are held together. A piezoelectric element 1 is placed between the plate 3 and the housing 2.
The holding plates 3 are sandwiched so that their longitudinal directions are perpendicular to each other, and are fixed by fastening one end of the holding plates 3 to the casing 2 with screws 4. The attachment portion 6 is for attaching the knock sensor to the side of the engine.
次に、動作について説明する。Next, the operation will be explained.
エンジン温度に対する形状記憶合金７の圧電素子１の長
手方向への伸びの関係が、第２図（ａ）に示す関係にな
るような形状記憶合金７を使用すれば、圧電素子１の念
も同様に伸び、圧電素子１の共振周波数ｆＩ、は、前記
（１）式によって第２図（ｂ）に示すように、ノックセ
ンサを取り付けたエンジン壁面温度が高くなるにつれて
、高くなる。このｆｏの温度変化に応じる変動を、第４
図に示すノッキングの特徴周波数ｆ、の温度変化に応じ
る変動に一致させるように圧電素子１のＱを変化させる
形状記憶合金７を使用することにより、エンジンの低温
から高温に至る全温度範囲のノッキングを感度よく検出
できるノックセンサが得られることになる。If the shape memory alloy 7 is used such that the longitudinal elongation of the piezoelectric element 1 has a relationship with the engine temperature as shown in FIG. The resonant frequency fI of the piezoelectric element 1 increases as the temperature of the wall surface of the engine to which the knock sensor is attached increases, as shown in FIG. 2(b) according to equation (1). The fluctuation of fo in response to temperature change is expressed as
By using the shape memory alloy 7 that changes the Q of the piezoelectric element 1 to match the fluctuation of the knocking characteristic frequency f, which corresponds to temperature changes, as shown in the figure, knocking can occur over the entire temperature range of the engine from low to high temperatures. This results in a knock sensor that can detect with high sensitivity.
（発明の効果）
本発明によれば、圧電素子を上下から挟持している形状
記憶合金が、エンジン温度の変化に従って形状を変える
ことに伴い、圧電素子の固定端がら先端までの長さを変
化させることによって、エンジン温度変化に応じる圧電
素子の共振周波数の変動が、ノンキングの特徴周波数の
変動と全く一致するので、エンジンの全温度範囲で生じ
るノッキングを高感度で検出できる。(Effects of the Invention) According to the present invention, the length from the fixed end of the piezoelectric element to the tip changes as the shape memory alloy that sandwiches the piezoelectric element from above and below changes its shape according to changes in engine temperature. By doing so, the variation in the resonant frequency of the piezoelectric element in response to changes in engine temperature completely matches the variation in the characteristic frequency of non-king, so that knocking occurring in the entire temperature range of the engine can be detected with high sensitivity.
第１図（ａ）は本発明の一実施例のノックセンサの側面
図、第１図（ｂ）は同実施例の斜視図、第２図（ａ）は
同実施例の形状記憶合金の長さとエンジン温度との関係
を示すグラフ、第２図（ｂ）は同実施例の、圧電素子の
共振周波数とエンジン温度との関係を示すグラフ、第３
図（ａ）は従来のノックセンサの側面図、第３図（ｂ）
は同斜視図、第４図はノッキングの特徴周波数とエンジ
ン温度との関係を示すグラフである。
１・・・バイモルフ型圧電素子、 ２・・・筐体、３・
・・おさえ板、 ４・・・ビス、 ５・・・電気出力端
子、 ６・・・取付部、 ７・・・形状記憶合金、 ト
・・圧電素子の固定端から先端までの長さ、 ｔ・・・
圧電素子の厚さ。
特許出願人 松下電器産業株式会社
第１図
置・・圧電宸Ｊ
２・・置俸
（ｂ） ３”’洞１１
４ ・・ヒ゛ ス
第２図
（ａ）
エン５゛ン湿友
第４図
工／ジン逼及
第３図
１１・・・圧電敷テ
１２°・筐吟FIG. 1(a) is a side view of a knock sensor according to an embodiment of the present invention, FIG. 1(b) is a perspective view of the same embodiment, and FIG. 2(a) is a length of the shape memory alloy of the same embodiment. FIG. 2(b) is a graph showing the relationship between the resonant frequency of the piezoelectric element and the engine temperature in the same example.
Figure (a) is a side view of a conventional knock sensor, Figure 3 (b)
is a perspective view of the same, and FIG. 4 is a graph showing the relationship between the characteristic frequency of knocking and the engine temperature. DESCRIPTION OF SYMBOLS 1... Bimorph type piezoelectric element, 2... Housing, 3...
... Holding plate, 4... Screw, 5... Electrical output terminal, 6... Mounting part, 7... Shape memory alloy, G... Length from the fixed end to the tip of the piezoelectric element, t ...
Thickness of piezoelectric element. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1: Piezoelectric cylinder J 2: (b) 3"' hole 11 4: Figure 2 (a) En 5-inch valve, Figure 4: / Jin connection Fig. 3 11...Piezoelectric plate 12°・Kingin
Claims (1)
変化に応じて形状を変化させる形状記憶合金でそれぞれ
の長手方向が相互に直交するように挟持し、さらにそれ
らをおさえ板と筐体との間に、前記圧電素子と前記おさ
え板のそれぞれの長手方向が直交するようにして挟み込
み、前記おさえ板の一端を前記筐体に固定し、前記形状
記憶合金の形状をエンジン温度変化に応じて変化させる
のに伴って、前記圧電素子の前記形状記憶合金による挟
持端から先端までの突出長を変化させることにより、前
記圧電素子の前記エンジン温度変化に応じる共振周波数
の変動を、前記エンジン温度変化範囲で生じるノッキン
グの特徴周波数の変動に一致させることを特徴とするノ
ックセンサ。One end of a piezoelectric element that detects vibration and generates electrical output is sandwiched between shape memory alloys that change shape according to temperature changes so that their longitudinal directions are perpendicular to each other, and then held between a holding plate and a housing. The piezoelectric element and the holding plate are sandwiched between the piezoelectric element and the holding plate so that their respective longitudinal directions are perpendicular to each other, one end of the holding plate is fixed to the housing, and the shape of the shape memory alloy is changed according to engine temperature changes. By changing the protrusion length of the piezoelectric element from the end held by the shape memory alloy to the tip thereof, the fluctuation of the resonant frequency of the piezoelectric element in response to the engine temperature change can be adjusted to A knock sensor characterized by matching the fluctuation of the characteristic frequency of knock occurring within a range of variation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5897487A JPS63225130A (en) | 1987-03-16 | 1987-03-16 | Knock sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5897487A JPS63225130A (en) | 1987-03-16 | 1987-03-16 | Knock sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63225130A true JPS63225130A (en) | 1988-09-20 |
Family
ID=13099821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5897487A Pending JPS63225130A (en) | 1987-03-16 | 1987-03-16 | Knock sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63225130A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004537827A (en) * | 2001-07-03 | 2004-12-16 | アール．フェース ブラッドベリー | Self-powered power switch start system |
| JP2014521295A (en) * | 2011-07-11 | 2014-08-25 | コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ | System for converting thermal energy into electrical energy |
| JP2014219343A (en) * | 2013-05-10 | 2014-11-20 | 積水化学工業株式会社 | Piezoelectric type vibration sensor, and leakage detection method using the same |
-
1987
- 1987-03-16 JP JP5897487A patent/JPS63225130A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004537827A (en) * | 2001-07-03 | 2004-12-16 | アール．フェース ブラッドベリー | Self-powered power switch start system |
| JP2014521295A (en) * | 2011-07-11 | 2014-08-25 | コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ | System for converting thermal energy into electrical energy |
| US9528502B2 (en) | 2011-07-11 | 2016-12-27 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | System for conversing thermal energy into electrical energy |
| JP2014219343A (en) * | 2013-05-10 | 2014-11-20 | 積水化学工業株式会社 | Piezoelectric type vibration sensor, and leakage detection method using the same |
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