JP2006064682A

JP2006064682A - Sound apparatus for measuring volume of engine combustion chamber

Info

Publication number: JP2006064682A
Application number: JP2004274174A
Authority: JP
Inventors: Yasushi Ishii; 泰石井
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-08-25
Filing date: 2004-08-25
Publication date: 2006-03-09

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly measure the volume of a combustion chamber, having a complicated shape in a dried state, as it is, with high accuracy, in an engine manufacturing process. <P>SOLUTION: A reference vessel is mounted on the combustion chamber of a transferred engine head block. An alternating volume change is given differentially to the spaces inside the reference vessel and the combustion chamber by a loudspeaker, the output of a second microphone for detecting the sound pressure, at a place where the sound pressure inside the communication pipe communicating through the space inside the reference vessel and the space inside the combustion chamber is rectified synchronously by the output of a first microphone for detecting the sound pressure in the reference vessel. The volume difference between the combustion chamber and a standard vessel is determined from a signal that is synchronously rectified, when the reference vessel is mounted to the standard vessel and a signal synchronously rectified, when the reference vessel is mounted to the combustion chamber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、エンジン製造工程において、複雑な形状をした燃焼室の容積と標準容器の容積との差を、音を利用して乾燥状態のままで精度よく測定する測定装置にかかわる。The present invention relates to a measuring apparatus for accurately measuring a difference between a volume of a combustion chamber having a complicated shape and a volume of a standard container in an engine manufacturing process in a dry state using sound.

自動車等のエンジンの燃焼室容積は、エンジンの性能やノッキングの特性に影響するので、その製造工程においては燃焼室容積を管理する必要がある。しかし燃焼室は吸排気弁や点火栓等が突出していて複雑な形状をしているので、寸法を計測してその容積を算出することは非常に難しい。Since the combustion chamber volume of an engine such as an automobile affects the engine performance and knocking characteristics, it is necessary to manage the combustion chamber volume in the manufacturing process. However, since the combustion chamber has a complicated shape with protruding intake and exhaust valves and spark plugs, it is very difficult to measure the dimensions and calculate the volume.

エンジンの製造工程では、燃焼室が組み込まれたエンジンヘッドブロックが燃焼室が上向きになるように転置されてベルトコンベアによって送られてくるが、この状態において燃焼室容積を測定するのに、従来は透明なアクリル板などを燃焼室の上に置き、その中央に穿たれた小孔にビュレットから液体を滴下し、燃焼室がいっぱいになるまでに滴下した液体の容積から燃焼室容積を求めるという方法が採られている。しかしながら、この方法は測定に長時間を要するだけでなく、測定後に使用した液体を除去しなければならないなど、問題点が多々ある。In the engine manufacturing process, the engine head block incorporating the combustion chamber is transposed so that the combustion chamber faces upward and is sent by a belt conveyor. Conventionally, in this state, in order to measure the combustion chamber volume, A method in which a transparent acrylic plate or the like is placed on the combustion chamber, liquid is dropped from the burette into a small hole drilled in the center, and the volume of the combustion chamber is calculated from the volume of liquid dropped until the combustion chamber is full. Has been adopted. However, this method not only requires a long time for the measurement, but also has many problems such as the liquid used after the measurement must be removed.

一方、複雑な形状の物体の体積を乾燥状態のままで測定する一つの方法として、スピーカなどの音源によって物体を入れた測定容器内部の空間に交番的な体積変化を与えて内部の気体を断熱的に圧縮膨張せしめ、そのときの交番的圧力変化をマイクロホン等で検出して物体の体積をその形状にかかわりなく求めるという方法がある。
特開平１０−３８６５８号公報特開２０００−１７１２８２号公報 On the other hand, as one method for measuring the volume of an object with a complicated shape in a dry state, the internal gas is insulated by applying an alternating volume change to the space inside the measurement container containing the object by a sound source such as a speaker. There is a method in which compression / expansion is performed and an alternating pressure change at that time is detected by a microphone or the like to determine the volume of the object regardless of its shape.
JP-A-10-38658 JP 2000-171282 A

この種の測定方法として、出願人は特許文献１において、基準容器と測定容器の双方にスピーカによって交番的体積変化を差動的に与え、そのときに生ずるこれらの容器内の気体の交番的圧力変化の大きさの比、すなわち音圧の大きさの比から、交番的体積変化の大きさには無関係に、かつ、容器内の気体の静圧力にも影響されないで、測定容器の中に入れた物体の体積とそれと比較される標準物体の体積との差を測定する音響式体積計を示した。出願人はまた、特許文献２において、上記の基準容器と測定容器を連通する連通管の内部の音圧を検出することにより、比較的精度の低いマイクロホンを用いて同様に体積差を測定できる音響式体積計を示した。以下、これら二つの体積計を前願発明と称する。As an example of this type of measurement method, in Japanese Patent Application Laid-Open No. H10-260260, the applicant differentially applies an alternating volume change to both the reference container and the measurement container by a speaker, and generates an alternating pressure of the gas in these containers. The ratio of the magnitude of the change, that is, the ratio of the sound pressure, is placed in the measurement container regardless of the magnitude of the alternating volume change and without being affected by the static pressure of the gas in the container. An acoustic volume meter that measures the difference between the volume of the measured object and the volume of the standard object compared with it is presented. The applicant also disclosed in Japanese Patent Application Laid-Open No. 2004-228688, an acoustic that can similarly measure a volume difference using a relatively low accuracy microphone by detecting the sound pressure inside the communication pipe that communicates the reference container and the measurement container. An expression volume meter was shown. Hereinafter, these two volume meters are referred to as the prior invention.

前願発明において、比較される標準物体の体積が既知であれば、これに測定された体積差を加えて被測定物体の体積を求めることができるが、燃焼室の場合には、求められるものは、前願発明におけるような測定容器の中に入れた物体の体積ではなく、燃焼室という容器の容積である。したがって、気体の音圧を利用するにしても、前願発明をそのまま適用することはできず、それとは異なった構造と測定方式を持つ新しい装置を創出する必要がある。In the invention of the previous application, if the volume of the standard object to be compared is known, the volume of the object to be measured can be obtained by adding the measured volume difference to the standard object. Is not the volume of the object placed in the measurement container as in the invention of the previous application, but the volume of the container called the combustion chamber. Therefore, even if the sound pressure of gas is used, the invention of the previous application cannot be applied as it is, and it is necessary to create a new apparatus having a structure and measurement method different from that.

上記のような課題を解決するための本発明装置の一形態は、一つの基準容器と、この基準容器を転置したエンジンヘッドブロックの燃焼室の上に載せたときに基準容器内部の空間と燃焼室内部の空間に交番的体積変化を差動的に与えるように設置されたスピーカなどの音源と、基準容器内部と燃焼室内部の空間を連通する連通管と、上記体積変化が与えられたことによって生ずる基準容器内部の交番的圧力変化、すなわち音圧、を検出する第１圧力検出器のマイクロホンと、上記連通管内部の音圧がほぼ０となる位置に設けられた検出函の音圧を検出する第２圧力検出器のマイクロホンと、第１圧力検出器の出力で第２圧力検出器の出力を同期整流する手段と、基準容器を燃焼室に載せたときの同期整流された信号の大きさと基準容器を既知の容積を有する標準容器に載せたときの同期整流された信号の大きさとから燃焼室の容積と標準容器の容積との差を求める手段とからなる。One form of the device of the present invention for solving the above problems is that one reference container and the space inside the reference container and the combustion when the reference container is placed on the combustion chamber of the engine head block to which the reference container is transferred A sound source such as a speaker installed so as to differentially give an alternating volume change to the indoor space, a communication pipe communicating the inside of the reference container and the space inside the combustion chamber, and the volume change given above The microphone of the first pressure detector that detects the alternating pressure change inside the reference container, that is, the sound pressure, and the sound pressure of the detection box provided at the position where the sound pressure inside the communication pipe becomes almost zero. The microphone of the second pressure detector to detect, means for synchronously rectifying the output of the second pressure detector with the output of the first pressure detector, and the magnitude of the synchronously rectified signal when the reference vessel is placed in the combustion chamber And the reference container is known And means for determining the difference between the volumes of the standard container combustion chamber from the magnitude of the synchronous rectified signal when placed on a standard container with a volume.

このように、連通管を使用するという本発明の方式によれば、比較的精度の低い安価なマイクロホンを用いて容積差を測定することができる。また、気体の断熱的な圧縮膨張を利用する原理からして、本発明においては容器の形状は測定に影響しないから、上記の比較される標準容器は燃焼室と同じ形状である必要はない。たとえば金属ブロックの上面を平面に加工し、この面に円柱状の窪みを穿ったものを標準容器として使用すれば、その容積は寸法測定により容易に求められる。したがって本発明装置により燃焼室の容積と上記の標準容器の容積との差が測定されたならば、この容積差に寸法から求められた標準容器の容積を加えることにより燃焼室容積が求められる。ただ、実際のエンジン製造工程では、燃焼室容積の絶対値は必ずしも必要ではなく、燃焼室容積の標準値からの容積差だけが知れればそれで十分という場合も多い。As described above, according to the method of the present invention using the communication pipe, the volume difference can be measured using an inexpensive microphone with relatively low accuracy. Further, from the principle of utilizing adiabatic compression and expansion of gas, in the present invention, since the shape of the container does not affect the measurement, the standard container to be compared does not need to have the same shape as the combustion chamber. For example, if the upper surface of a metal block is machined into a flat surface and a cylindrical recess is formed on this surface, the volume can be easily obtained by measuring the dimensions. Therefore, when the difference between the volume of the combustion chamber and the volume of the standard container is measured by the apparatus of the present invention, the volume of the combustion chamber is obtained by adding the volume of the standard container obtained from the dimensions to this volume difference. However, in an actual engine manufacturing process, the absolute value of the combustion chamber volume is not always necessary, and it is often sufficient if only the volume difference from the standard value of the combustion chamber volume is known.

本発明装置を使用すれば、エンジン燃焼室の容積を、液体を使うことなく乾燥状態のままで検査することができる。所要時間は燃焼室一つ当たり数秒以下で済むのでエンジンの生産効率は大いに向上する。以下、実施例により本発明の動作原理などを詳細に説明する。If the apparatus of the present invention is used, the volume of the engine combustion chamber can be inspected in a dry state without using liquid. Since the time required is less than a few seconds per combustion chamber, the production efficiency of the engine is greatly improved. Hereinafter, the working principle of the present invention will be described in detail by way of examples.

図１において、１は内部空間の容積がＶ_１の基準容器、２は上下が転置されたエンジンヘッドブロックで３は容積Ｖの燃焼室である。基準容器１はその下部にアダプタ８が付けられており、この状態で基準容器１を燃焼室３の上に載せるが、このときアダプタ８の下面とエンジンヘッドブロック２の上面が密着して燃焼室３内部の空間が音響的にシールされる。しかし、アダプタを付けずに基準容器１をそのまま燃焼室の上に載せても測定に必要な音響的シールが得られる場合もあるので、アダプタ８は必須のものではない。In FIG. 1, reference numeral 1 is a reference container having a volume V _{1 in} the internal space, 2 is an engine head block in which the top and bottom are transposed, and 3 is a combustion chamber having a volume V. The reference container 1 has an adapter 8 attached to the lower part thereof, and the reference container 1 is placed on the combustion chamber 3 in this state. At this time, the lower surface of the adapter 8 and the upper surface of the engine head block 2 are in close contact with each other. The space inside 3 is acoustically sealed. However, the adapter 8 is not indispensable because an acoustic seal necessary for measurement may be obtained even if the reference container 1 is placed on the combustion chamber as it is without attaching an adapter.

基準容器１の隔板４にはスピーカ６が付けられており、端子１３を通して交番的な駆動電気信号ｓがスピーカ６に供給されるとスピーカのコーン状の振動板７が振動し、その表裏によって、基準容器１と燃焼室３の内部空間に微小な交番的体積変化が差動的に与えられる。その結果生じた基準容器１内部の音圧はマイクロホン１１によって検出され、その出力信号ｅ_１は信号処理装置１５にとりこまれる。隔板４にはまた、基準容器１と燃焼室３の内部空間を連通する連通管５と５’があり、その間に設けられた検出函９内部の音圧は可撓性チューブ１４によってマイクロホン１２に導かれて検出され、その出力信号ｅ_２も信号処理装置１５にとりこまれる。なおＶ_２は隔板４の下の空間とこれに通ずる容積Ｖの燃焼室３の空間の全部の容積を表わす。A speaker 6 is attached to the partition plate 4 of the reference container 1. When an alternating drive electric signal s is supplied to the speaker 6 through the terminal 13, the cone-shaped diaphragm 7 of the speaker vibrates, A minute alternating volume change is differentially given to the internal space of the reference container 1 and the combustion chamber 3. The resulting sound pressure inside the reference container 1 is detected by the microphone 11, and the output signal e ₁ is captured by the signal processing device 15. The partition plate 4 also has communication pipes 5 and 5 ′ communicating with the internal space of the reference container 1 and the combustion chamber 3, and the sound pressure inside the detection box 9 provided therebetween is transmitted by the flexible tube 14 to the microphone 12. The output signal e ₂ is also captured by the signal processor 15. V ₂ represents the total volume of the space below the partition plate 4 and the space of the combustion chamber 3 having a volume V communicating therewith.

いま、スピーカ駆動信号ｓによってスピーカ６が駆動され、振動板７が押し出されて隔板４より下の全空間の容積Ｖ_２がΔＶ_Ｖなる微小体積だけ圧縮されるものとすると、基準容器１の内部容積Ｖ_１はΔＶ_Ｖだけ膨張する。また連通管５、５’を通して隔板４より下の空間にΔＶ_Ｐなる微小体積の気体が流入するものとすると、基準容器１からはΔＶ_Ｐの体積の気体が連通管５、５’を通して流出する。このとき基準容器１の内部空問および隔板４より下の空間に生ずる微小圧力変化をそれぞれ−ΔＰ_１、ΔＰ_２とし、またNow, assuming that the speaker 6 is driven by the speaker drive signal s, the diaphragm 7 is pushed out, and the volume V ₂ of the entire space below the partition plate 4 is compressed by a minute volume of ΔV _V , the reference container 1 internal volume _{V 1} is expanded only ΔV _V. The outflow through 'the [Delta] V _P becomes the minute volume gas in the space below the diaphragm 4 through is assumed to flow, communication pipe 5 and 5 gas volume [Delta] V _P from the reference container 1' communicating pipe 5,5 To do. At this time, the minute pressure changes generated in the internal space of the reference container 1 and the space below the partition plate 4 are set to −ΔP ₁ and ΔP ₂ , respectively.

数１Number 1

ΔＶ＝ΔＶ_Ｖ＋ΔＶ_Ｐ ΔV = ΔV _V + ΔV _P

とおくと、気体の断熱変化の関係式よりつぎのようになる。Then, from the relational expression of the adiabatic change of gas, it becomes as follows.

数２Number 2

ΔＰ_１／Ｐ_０＝γΔＶ／Ｖ_１ ΔP ₁ / P ₀ = γΔV / V ₁

数３Number 3

ΔＰ_２／Ｐ_０＝γΔＶ／Ｖ_２ ΔP ₂ / P ₀ = γΔV / V ₂

ここでＰ_０は基準容器１および隔板４より下の空間の内部の気体、通常は空気、の平均的な静圧であり、γ（ガンマ）はその気体の比熱比で、空気では約１．４である。上記二つの式よりHere, P ₀ is the average static pressure of the gas inside the space below the reference container 1 and the partition plate 4, usually air, and γ (gamma) is the specific heat ratio of the gas, and about 1 for air. .4. From the above two formulas

数４Number 4

ΔＰ_１／ΔＰ_２＝Ｖ_２／Ｖ_１ ΔP ₁ / ΔP ₂ = V ₂ / V ₁

なる関係式がえられる。すなわち圧力変化の大きさの比は体積変化ΔＶ、静圧力Ｐ_０、比熱比γにはよらず、容積比Ｖ_２／Ｖ_１によって定まる。The following relational expression is obtained. That is, the ratio of the magnitude of the pressure change is determined not by the volume change ΔV, the static pressure P ₀ , and the specific heat ratio γ but by the volume ratio V ₂ / V ₁ .

スピーカ６を駆動する交番的信号ｓが周波数ｆの正弦波の場合には、時間をｔで表わすと、−ΔＰ_１とΔＰ_２はそれぞれ次式で示すような、互いに１８０度位相の異なる周波数ｆの正弦波音圧となる。When the alternating signal s driving the speaker 6 is a sine wave having a frequency f, when the time is represented by t, −ΔP ₁ and ΔP ₂ are each a frequency f having a phase difference of 180 degrees from each other as shown by the following equations. The sine wave sound pressure.

数５Number 5

−ΔＰ_１＝−Ｐ_１ｓｉｎ２πｆｔ−ΔP ₁ = −P ₁ sin2πft

数６Equation 6

ΔＰ_２＝Ｐ_２ｓｉｎ２πｆｔΔP ₂ = P ₂ sin2πft

ここでＰ_１、Ｐ_２は音圧振幅で、それらの比はWhere P ₁ and P ₂ are sound pressure amplitudes, and their ratio is

数７Number 7

Ｐ_１／Ｐ_２＝Ｖ_２／Ｖ_１ _{_{_{P 1 / P 2 = V 2}}} / V 1

である。It is.

図２は連通管５、５’および検出函９の内部構造を示す。長さＬ_２の連通管５’の下端は隔板４より下の容積Ｖ_２の空間に開口していて、そこでの音圧はΔＰ_２であり、長さＬ_１の連通管５の上端は容積Ｖ_１の基準容器１の内部空間に開口していて、そこでの音圧は−ΔＰ_１である。したがって検出函９内部の音圧は、上記二つの音圧を連通管５’の音響インピーダンスＺ_２と連通管５の音響インピーダンスＺ_１とで比例按分したものになり、この音圧が可撓性チューブ１４を通ってマイクロホン１２によって検出される。そしてFIG. 2 shows the internal structure of the communication tubes 5, 5 ′ and the detection box 9. The lower end of the communication pipe 5 ′ having a length L ₂ opens into a space having a volume V ₂ below the partition plate 4, and the sound pressure there is ΔP ₂ , and the upper end of the communication pipe 5 having a length L ₁ is it is open to the internal space of the reference vessel 1 volume V _1, the sound pressure at which is -DerutaP _1. Therefore detection box making 9 inside the sound pressure becomes to those pro rata with the acoustic impedance Z ₁ of the acoustic impedance Z ₂ and communicating pipe 5 of the two sound pressure connecting pipe 5 ', this sound pressure flexible It is detected by the microphone 12 through the tube 14. And

数８Number 8

Ｚ_１／Ｚ_２＝Ｐ_１／Ｐ_２ _{_{_{Z 1 / Z 2 = P 1}}} / P 2

の場合には、検出函９内部の音圧の大きさはほとんど０になる。In this case, the magnitude of the sound pressure inside the detection box 9 is almost zero.

ここで検出函９の作用と効果を説明する。本発明装置では、連通管５、５’の長さＬ_１、Ｌ_２を変えて上記の音響インピーダンスＺ_１、Ｚ_２を調整するなどの方法によって検出函９内部の音圧がほぼ０となるようにして、その状態において容積差の測定を行なう。したがってマイクロホン１２によって検出される音圧を小さい。一方、スピーカ６が周波数ｆの信号で駆動されると、連通管５、５’の内部に同じ周波数の振動流が生ずるが、その流速をｖとしその気体の密度をρとすると、ρｖ^２／２なる大きさの動圧が５、５’内部に発生する。この動圧の大きさは検出すべき音圧より大きくなる場合もあるが、連通管５、５’の内部断面積に比べて大きな内部断面積を有する検出函９を設けてそこにおける流速を小さくすることにより、上記の動圧を小さくすることができる。上記の動圧は流速ｖの２乗に比例するから、検出函９を設けることは信号対雑音比を良くするためにきわめて効果的である。Here, the operation and effect of the detection box 9 will be described. In the device of the present invention, the sound pressure inside the detection box 9 becomes almost zero by adjusting the acoustic impedances Z ₁ and Z ₂ by changing the lengths L ₁ and L ₂ of the communication pipes 5 and 5 ′. Thus, the volume difference is measured in that state. Therefore, the sound pressure detected by the microphone 12 is small. On the other hand, when the speaker 6 is driven by a signal having a frequency f, an oscillating flow having the same frequency is generated inside the communication pipes 5 and 5 ′. If the flow velocity is v and the gas density is ρ, ρv ² / A dynamic pressure of 2 is generated inside 5, 5 ′. Although the magnitude of this dynamic pressure may be greater than the sound pressure to be detected, a detection box 9 having a larger internal cross-sectional area than the internal cross-sectional area of the communication pipes 5 and 5 'is provided to reduce the flow velocity there. By doing so, the above-mentioned dynamic pressure can be reduced. Since the above dynamic pressure is proportional to the square of the flow velocity v, it is very effective to provide the detection box 9 in order to improve the signal-to-noise ratio.

図３は信号処理装置１５の内部構造の一例である。信号発生器２０は交番的なスピーカ駆動信号ｓを発生し、その信号はスピーカ６に供給される。マイクロホン１２の信号ｅ_２は増幅器２２で増幅され同期整流器１６の入力となる。一方マイクロホン１１の信号ｅ_１は増幅器２１で増幅され、位相基準の信号として同期整流器１６のもう一つの入力となる。信号ｅ_１は基準容器１内部の音圧−ΔＰ_１を表わすが、同期整流器１６ではマイクロホン１２の信号ｅ_２の波形の内で信号ｅ_１と同相の成分が検出され、その同相成分の大きさを表わす出力信号Ｑは指示計器１８によって表示される。１７は加算器で、同期整流器の出力Ｑに−Ｑ_Ｓなるバイアスを与えるものであるが、その作用については後述する。なお、隔板４の下の空間の音圧ΔＰ_２を可撓性チューブによってマイクロホン１１に導入して検出し、その出力信号を位相基準の信号として同期整流器１６に与えて、これと同相の成分を信号ｅ_２の中から抽出するようにしてもよい。この場合は基準となる信号の位相が１８０°変わるわけであるから、同期整流器１６の出力Ｑの極性は反転する。FIG. 3 shows an example of the internal structure of the signal processing device 15. The signal generator 20 generates an alternating speaker driving signal s, which is supplied to the speaker 6. The signal e _{2 of the} microphone 12 is amplified by the amplifier 22 and input to the synchronous rectifier 16. On the other hand, the signal e _{1 of the} microphone 11 is amplified by the amplifier 21 and becomes another input of the synchronous rectifier 16 as a phase reference signal. Signal e ₁ represents an acoustic pressure -DerutaP ₁ of the internal reference vessel 1, the signal e ₁ and phase components within the synchronous rectifier 16 in the waveform of the signal e ₂ microphones 12 is detected, the magnitude of the in-phase component The output signal Q representing is displayed by the indicating instrument 18. 17 is an adder, but is intended to provide a -Q _S becomes biased to the output Q of the synchronous rectifiers will be described later operation thereof. The sound pressure ΔP ₂ in the space below the partition plate 4 is detected by introducing it into the microphone 11 through a flexible tube, and its output signal is given to the synchronous rectifier 16 as a phase reference signal, and the component in phase with this May be extracted from the signal e ₂ . In this case, since the phase of the reference signal changes by 180 °, the polarity of the output Q of the synchronous rectifier 16 is inverted.

本発明装置はマイクロホン１２によって検出される検出函９の音圧がほぼ０となるような状態で作動するが、そのために、数８の関係式がほぼ満たされるように連通管５、５’の音響インピーダンスＺ_１、Ｚ_２を調整する。前述したように連通管５、５’の長さＬ_１、Ｌ_２を変えることもその調整方法の一つであるが、連通管５、５’の内径を変えるという方法もある。また、基準容器１の容積Ｖ_１を変えると、数７の関係によってＰ_１／Ｐ_２が変わるから、この比がＺ_１／Ｚ_２にほぼ等しくなるように基準容器１の容積Ｖ_１を定めるというのも一つの方法である。The device according to the present invention operates in such a state that the sound pressure of the detection box 9 detected by the microphone 12 is almost zero. For this reason, the communication pipes 5 and 5 ′ are so arranged that the relational expression of Formula 8 is substantially satisfied. The acoustic impedances Z ₁ and Z ₂ are adjusted. As described above, changing the lengths L ₁ and L ₂ of the communication pipes 5 and 5 ′ is one of the adjustment methods, but there is also a method of changing the inner diameter of the communication pipes 5 and 5 ′. Also, changing the volume _{V 1} of the reference container 1, from _P 1 / _{P 2} by the relation of 7 changes, determine the volume _{V 1} of the reference container 1 so that this ratio is approximately equal to _Z 1 / _{Z 2} That is one way.

図４のグラフは、同期整流器１６の出力信号Ｑと、エンジン燃焼室の容積Ｖと標準容器の容積Ｖ_Ｓとの容積差Ｖ_Ｄ The graph of FIG. 4 shows the output signal Q of the synchronous rectifier 16, the volume difference V _D between the engine combustion chamber volume V and the standard vessel volume V _S.

数９Number 9

Ｖ_Ｄ＝Ｖ−Ｖ_Ｓ V _D = V−V _S

の関係を表わす。このＶ_Ｄが小さくなるように、標準容器は、その容積Ｖ_Ｓが測定されるエンジン燃焼室容積Ｖに近いものを使用する。本発明装置のキャリブレーションの手続きは、まず基準容器１を標準容器の上に載せて、そのときのＱの値としてＱ_Ｓを得る。これはグラフのＱ_Ｓ点に対応する。つぎに容積Ｖ_Ｔを有する第２の標準容器の上に基準容器を載せて、そのときのＱの値としてＱ_Ｔを得る。これはグラフのＴ点に対応する。Ｑ_Ｓ点とＴ点を結んだ直線が、基準容器を測定される燃焼室の上に載せたときのＱの値と、燃焼室容積Ｖと標準容積Ｖ_Ｓとの容積差Ｖ_Ｄの関係を表わす。すなわちRepresents the relationship. The V _D so smaller standard container uses close to the engine combustion chamber volume V of the volume V _S is measured. Procedures calibration of the device of the present invention, first a reference vessel 1 placed on a standard container, obtaining Q _S as the value of Q at that time. This corresponds to the _QS point of the graph. Next, the reference container is placed on the second standard container having the volume V _T, and Q _T is obtained as the Q value at that time. This corresponds to the T point of the graph. Q straight line connecting _the point _S and T point, the value of Q when placed on the combustion chamber to be measured the reference container, the relationship between the volume difference V _D between the combustion chamber volume V and the standard volume V _S Represent. Ie

数１０Number 10

Ｋ＝（Ｖ_Ｔ−Ｖ_Ｓ）／（Ｑ_Ｔ−Ｑ_Ｓ）K = (V _T −V _S ) / (Q _T −Q _S )

とするとIf

数１１Equation 11

Ｖ_Ｄ＝Ｋ（Ｑ−Ｑ_Ｓ）V _D = K (Q−Q _S )

が測定式である。さらに図３に示したように、加算器１７において−Ｑ_ＳなるバイアスをＱに加えて（Ｑ−Ｑ_Ｓ）の信号を作りこれを指示計器１８の入力にすると、容積差Ｖ_Ｄの値を、その正負の符号も含めて、指示計器１８で直読することができる。容積差Ｖ_Ｄの値が測定されれば、これに標準容器の容積Ｖ_Ｓを加えてIs a measurement formula. As further shown in FIG. 3, when the input of the adder -Q _S becomes biased in 17 in addition to the Q (Q-Q _S) creates a signal which indicating instrument 18, the value of the volume difference V _D , Including the sign of the sign, can be directly read by the indicating instrument 18. If the value of the volume difference V _D is measured, add the volume V _{S of the} standard container to this

数１２Number 12

Ｖ＝Ｖ_Ｄ＋Ｖ_Ｓ V = V _D + V _S

として燃焼室容積Ｖの値を知ることができる。As a result, the value of the combustion chamber volume V can be known.

容積差Ｖ_Ｄと同期整流された信号Ｑの関係は一般には非線形であり、数１１に示した線形の測定式は容積差Ｖ_Ｄの絶対値が小さいときに近似的に成り立つものである。工場の製造ラインでは同一種の多数のエンジンが製造され、それらの燃焼室容積の分布の範囲は１％程度である。したがって、それらの燃焼室容積に近い容積の標準容器を使用すれば、容積差Ｖ_Ｄの絶対値は数１１の測定式が十分に成り立つような小さな値になる。そして測定された小さな値の容積差Ｖ_Ｄに標準容器の容積Ｖ_Ｓを加えたものが燃焼室容積Ｖであるから、マイクロホン１２の感度変化により、仮に容積差Ｖ_Ｄの測定値に１０％の誤差を生じても、最終的にえられる燃焼室容積Ｖの値に対してはたかだか０．１％の誤差を生ずるに過ぎない。温度変化などにより測定装置内部の気体の密度や粘度が変化すると連通管の音響インピーダンスＺ_１、Ｚ_２が変化し、その結果、検出函９内部の音圧が変化して容積差Ｖ_Ｄの測定値に誤差を生ずる。しかしこの変化は時間的に緩やかで、数十分に１回程度キャリブレーションを行なうことによりその影響を回避できる。The relationship between the volume difference V _D and the synchronously rectified signal Q is generally non-linear, and the linear measurement equation shown in Equation 11 is approximately established when the absolute value of the volume difference V _D is small. Many engines of the same type are manufactured in the factory production line, and the distribution range of the combustion chamber volume is about 1%. Therefore, if standard containers having a volume close to those combustion chamber volumes are used, the absolute value of the volume difference V _D becomes a small value that satisfies the measurement formula of Equation 11 sufficiently. And since the volume difference V _D of the measured small value plus the volume V _S of the standard container is combustion chamber volume V, the change in sensitivity of the microphone 12, 10% if the measured value of the volume difference V _D Even if an error occurs, the error of the combustion chamber volume V finally obtained is only 0.1%. When the density or viscosity of the gas inside the measuring device changes due to a temperature change or the like, the acoustic impedances Z ₁ and Z _{2 of the} communication tube change, and as a result, the sound pressure inside the detection box 9 changes and the volume difference V _D is measured. An error occurs in the value. However, this change is gradual in time, and the influence can be avoided by performing calibration about several tens of times.

図５はディジタル計算機を使用した信号処理装置１５の構成の一例である。マイクロホン１１、１２の出力信号ｅ_１およびｅ_２は増幅器２１および２２によって増幅されたのち、それぞれアナログディジタル変換器２３および２４によってディジタル量に変換されディジタル計算機２５にとり込まれる。２６は信号発生器で、交番的なスピーカ駆動信号ｓを発生してスピーカ６に供給するとともに、同期パルスを発生し、導線２７を通してアナログディジタル変換器２３、２４とディジタル計算機２５に供給する。上記のアナログディジタル変換と計算機へのデータのとり込みはこの同期パルスに同期して行なわれる。上記の同期パルスをディジタル計算機２５で発生して２３と２４に供給し、アナログディジタル変換と計算機へのデータのとり込みを計算機自身で制御するようにしてもよい。FIG. 5 shows an example of the configuration of the signal processing device 15 using a digital computer. The output signals e ₁ and e ₂ of the microphones 11 and 12 are amplified by the amplifiers 21 and 22, converted into digital quantities by the analog / digital converters 23 and 24, respectively, and taken into the digital computer 25. A signal generator 26 generates an alternating speaker driving signal s and supplies it to the speaker 6, and also generates a synchronization pulse, which is supplied to the analog / digital converters 23 and 24 and the digital computer 25 through the conductor 27. The analog-to-digital conversion and the data fetching into the computer are performed in synchronism with this synchronizing pulse. The above-mentioned synchronization pulse may be generated by the digital computer 25 and supplied to 23 and 24 so that the analog / digital conversion and the data fetching into the computer may be controlled by the computer itself.

計算機２５の内部では、上記のとりこまれたｅ_１およびｅ_２の信号波形についてフーリエ変換を行ない、ｅ_１の振幅Ｅ_１と位相θ_１およびｅ_２の振幅Ｅ_２と位相θ_２を算出する。そしてInside the computer 25 performs Fourier transform on the the captured _{e 1} and _{e 2} of the signal waveform, it calculates the amplitude _{E 2} and the phase theta ₂ of the amplitude _{E 1} and phase theta ₁ and _{e 2} of _{e 1.} And

数１３Equation 13

Ｑ＝Ｅ_２ｃｏｓ（θ_２−θ_１）Q = E ₂ cos (θ ₂ −θ ₁ )

を算出するが、このＱは信号ｅ_２の中の信号ｅ_１と同相の成分の振幅であり、図３の同期整流器１６の出力Ｑと同等である。数１３のＱを用い、実施例１の場合と同様にキャリブレーションを行なって数１１の測定式を作成して計算機の中に記憶し、その測定式を使って容積差Ｖ_Ｄ求める。また、標準容器の容積Ｖ_Ｓの値を計算機に記憶しておけば、測定されたＶ_Ｄの値から数１２によって燃焼室容積Ｖを求めることができる。Calculating a, this Q is the amplitude of the signals e ₁ and phase components in the signal e _2, it is equivalent to the output Q of the synchronous rectifier 16 in FIG. Using Q in Equation 13, calibration is performed in the same manner as in the first embodiment, and a measurement equation of Equation 11 is created and stored in the computer, and the volume difference V _D is obtained using the measurement equation. Further, by storing the value of the volume V _S of the standard container in the computer, it is possible to determine the combustion chamber volume V by the number 12 from the value of the measured V _D.

計算機を使用する場合には、信号Ｑを信号ｅ_１の振幅Ｅ_１で除した量When using a calculator, the amount obtained by dividing the signal Q by the amplitude E ₁ of the signal e ₁

数１４Number 14

Ｒ＝Ｑ／Ｅ_１ R = Q / E ₁

を算出して、このＲをＱの代わりに用いた測定式And a measurement formula using this R instead of Q

数１５Number 15

Ｖ_Ｄ＝Ｋ’（Ｒ−Ｒ_Ｓ）V _D = K ′ (R−R _S )

をキャリブレーションを行なって作成することができる。ここでCan be created by calibration. here

数１６Equation 16

Ｋ’＝（Ｖ_Ｔ−Ｖｓ）／（Ｒ_Ｔ−Ｒ_Ｓ）K ′ = (V _T −Vs) / (R _T −R _S )

であり、Ｒ_Ｔ、Ｒ_ＳはそれぞれＱ_Ｔ、Ｑ_Ｓに対応するＲの値である。数１５の式を使って容積差Ｖ_Ｄを測定すると、これは基準容器１の中の音圧の大きさが一定となるようにスピーカ駆動信号ｓの振幅を制御しつつ信号Ｑを使って容積差を測定することに等価であり、容積差の測定精度の向上に効果がある。R _T and R _S are values of R corresponding to Q _T and Q _S , respectively. When the volume difference V _D is measured using the equation (15), the volume is calculated using the signal Q while controlling the amplitude of the speaker driving signal s so that the sound pressure in the reference container 1 is constant. This is equivalent to measuring the difference and is effective in improving the measurement accuracy of the volume difference.

本発明の一実施例の装置である。It is an apparatus of one Example of this invention. 検出函の構造の一例である。It is an example of the structure of a detection box. 本発明で使用される信号処理装置の一例である。It is an example of the signal processing apparatus used by this invention. 本発明の測定式のグラフである。It is a graph of the measurement type | formula of this invention. ディジタル計算機を用いた信号処理装置の一例である。It is an example of the signal processing apparatus using a digital computer.

符号の説明Explanation of symbols

１内部容積Ｖ_１の基準容器
２エンジンヘッドブロック
３容積Ｖの燃焼室
４隔板
７スピーカのコーン状の振動板
１１、１２マイクロホン
１３端子
１４可撓性チューブ
１７加算器
１８指示計器
２１、２２増幅器
２７導線DESCRIPTION OF SYMBOLS ₁ Reference | standard container 2 of internal volume V ₁ Engine head block 3 Combustion chamber 4 of volume V Diaphragm 7 Speaker-cone diaphragm 11, 12 Microphone 13 Terminal 14 Flexible tube 17 Adder 18 Indicators 21, 22 Amplifier 27 Conductor

Claims

基準容器と、基準容器を転置したエンジンヘッドブロックの燃焼室に載せたときに基準容器内部の空間と燃焼室内部の空間に交番的体積変化を差動的に与える手段と、基準容器内部の空間と燃焼室内部の空間とを連通する連通管と、連通管内部の音圧がほぼ０となる場所に設けた検出函と、基準容器内部の空間または燃焼室内部の空間の音圧を検出する第１圧力検出器と、検出函内部の音圧を検出する第２圧力検出器と、第１圧力検出器の出力信号で第２圧力検出器の出力信号を同期整流する手段と、燃焼室とほぼ同容積の標準容器に基準容器を載せたときの同期整流によって得られた信号の大きさと燃焼室に基準容器を載せたときの同期整流によって得られた信号の大きさとにより燃焼室の容積と標準容器の容積との差を求める手段とからなる音響装置。 A reference vessel, means for differentially changing an alternating volume between the space inside the reference vessel and the space inside the combustion chamber when placed in the combustion chamber of the engine head block to which the reference vessel is transposed, and the space inside the reference vessel A communication pipe that communicates with the space inside the combustion chamber, a detection box provided in a place where the sound pressure inside the communication pipe becomes almost zero, and the sound pressure in the space inside the reference container or the space inside the combustion chamber A first pressure detector, a second pressure detector for detecting the sound pressure inside the detection box, means for synchronously rectifying the output signal of the second pressure detector with the output signal of the first pressure detector, a combustion chamber, The volume of the combustion chamber is determined by the magnitude of the signal obtained by synchronous rectification when the reference container is placed on a standard container of approximately the same volume and the magnitude of the signal obtained by synchronous rectification when the reference container is placed on the combustion chamber. From the means to find the difference from the volume of the standard container That the acoustic device.

基準容器と、基準容器を転置したエンジンヘッドブロックの燃焼室に載せたときに基準容器内部の空間と燃焼室内部の空間に交番的体積変化を差動的に与える手段と、基準容器内部の空間と燃焼室内部の空間とを連通する連通管と、連通管内部の音圧がほぼ０となる場所に設けた検出函と、基準容器内部の空間または燃焼室内部の空間の音圧を検出する第１圧力検出器と、検出函内部の音圧を検出する第２圧力検出器と、第１圧力検出器の出力信号で第２圧力検出器の出力信号を同期整流する手段と、燃焼室とほぼ同容積の標準容器に基準容器を載せたときの同期整流によって得られた信号の大きさと燃焼室に基準容器を載せたときの同期整流によって得られた信号の大きさとにより燃焼室の容積と標準容器の容積との差を求める手段と、この求められた容積の差に標準容器の容積を加えて燃焼室の容積を求める手段とからなる音響装置。 A reference vessel, means for differentially changing an alternating volume between the space inside the reference vessel and the space inside the combustion chamber when placed in the combustion chamber of the engine head block to which the reference vessel is transposed, and the space inside the reference vessel A communication pipe that communicates with the space inside the combustion chamber, a detection box provided in a place where the sound pressure inside the communication pipe becomes almost zero, and the sound pressure in the space inside the reference container or the space inside the combustion chamber A first pressure detector, a second pressure detector for detecting the sound pressure inside the detection box, means for synchronously rectifying the output signal of the second pressure detector with the output signal of the first pressure detector, a combustion chamber, The volume of the combustion chamber is determined by the magnitude of the signal obtained by synchronous rectification when the reference container is placed on a standard container of approximately the same volume and the magnitude of the signal obtained by synchronous rectification when the reference container is placed on the combustion chamber. A means for determining the difference from the volume of the standard container, and Acoustic device to the difference between the determined volume and means for determining the volume of the combustion chamber by adding the volume of the standard container.

上記第１圧力検出器の出力信号で第２圧力検出器の出力信号を同期整流する手段としてディジタル計算機を用いた請求項１または請求項２の装置。 3. An apparatus according to claim 1, wherein a digital computer is used as means for synchronously rectifying the output signal of the second pressure detector with the output signal of the first pressure detector.

上記燃焼室とほぼ同容積の標準容器に基準容器を載せたときの同期整流によって得られた信号の大きさと燃焼室に基準容器を載せたときの同期整流によって得られた信号の大きさとにより燃焼室の容積と標準容器の容積との差を求める手段としてディジタル計算機を用いた請求項１または請求項２の装置。 Combustion based on the magnitude of the signal obtained by synchronous rectification when the reference container is placed on a standard container having the same volume as the combustion chamber and the magnitude of the signal obtained by synchronous rectification when the reference container is placed on the combustion chamber 3. An apparatus according to claim 1, wherein a digital computer is used as means for determining the difference between the chamber volume and the standard container volume.

上記求められた容積の差に標準容器の容積を加えて燃焼室の容積を求める手段としてディジタル計算機を用いた請求項２の装置。 3. An apparatus according to claim 2, wherein a digital computer is used as means for obtaining the volume of the combustion chamber by adding the volume of the standard vessel to the difference in the obtained volumes.

上記同期整流によって得られた信号に代えて、上記同期整流によって得られた信号を上記第１圧力変換器の出力の大きさで除した信号を用いる請求項４の装置。 5. The apparatus according to claim 4, wherein a signal obtained by dividing the signal obtained by the synchronous rectification by the magnitude of the output of the first pressure transducer is used instead of the signal obtained by the synchronous rectification.