SE461291B - MADE TO MONITOR PERIODIC VIBRATIONS OF A MACHINE EQUIPMENT - Google Patents
MADE TO MONITOR PERIODIC VIBRATIONS OF A MACHINE EQUIPMENTInfo
- Publication number
- SE461291B SE461291B SE8804663A SE8804663A SE461291B SE 461291 B SE461291 B SE 461291B SE 8804663 A SE8804663 A SE 8804663A SE 8804663 A SE8804663 A SE 8804663A SE 461291 B SE461291 B SE 461291B
- Authority
- SE
- Sweden
- Prior art keywords
- vibration
- sequence
- characteristic
- time
- frequency spectrum
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
- G01H1/003—Measuring characteristics of vibrations in solids by using direct conduction to the detector of rotating machines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P17/00—Testing of ignition installations, e.g. in combination with adjusting; Testing of ignition timing in compression-ignition engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Description
10 15 20 30 35 461 291 Uppfinningen och dess fördelar förklaras närmare nedan med hänvisning till bifogade ritningar, som schematiskt askadliggör ett utföringsexempel. 10 15 20 30 35 461 291 The invention and its advantages are explained in more detail below reference to the accompanying drawings, which schematically neutralize an embodiment.
Pig. 1 visar schematiskt ett antal fartygsdieselmotorer, en samlingsväxel samt ett övervakningssystem för ut- förande av sättet enligt uppfinningen; och Fig. 2 visar ett blockschema över de väsentliga förfarings- stegen enligt uppfinningen.Pig. 1 schematically shows a number of marine diesel engines, a gear unit and a monitoring system for practicing the method according to the invention; and Fig. 2 shows a block diagram of the essential procedure the steps according to the invention.
I fig. 1 visas starkt schematiskt ett antal parallella, fler- cylindriga fartygsdieselmotorer D1,...,DN, vilka med sina motoraxlar M1,...,MN är anslutna till en samlingsväxel VX med en gemensam utgående axel UA. En första vibrationssensor A1,...,AN är anbringad på samlingsväxeln VX pa ett ställe i förlängningen av resp. motoraxel M1,...,MN. Denna sensor A1,...,AN användes dels för övervakning av tillhörande lager och drev i samlings- växeln, dels för övervakning och analys av tändningssekvensen i resp. dieselmotor under två motorvarv, motsvarande en period. En ytterligare sensor B1,...,BN är anbringad på motorblocket hos resp. dieselmotor, nämligen pa den cylinder, som kommer först i tändningssekvensen. Denna sensor B1,...,BN utnyttjas såsom triggsensor.Fig. 1 shows very diagrammatically a number of parallel, multiple cylindrical marine diesel engines D1, ..., DN, which with their motor shafts M1, ..., MN are connected to a gear unit VX with a common output shaft UA. A first vibration sensor A1, ..., AN is mounted on the VX assembly in one place in the extension of resp. motor shaft M1, ..., MN. This sensor A1, ..., AN was used partly for monitoring associated bearings and gears in the gear unit, partly for monitoring and analysis of the ignition sequence in resp. diesel engine during two engine revolutions, corresponding to one period. One additional sensor B1, ..., BN is mounted on the engine block of resp. diesel engine, namely on the cylinder, which comes first in the ignition sequence. This sensor B1, ..., BN is used as trigger sensor.
Den sensor, som användes för övervakning av tändningssekvensen, är sålunda placerad pa avstand från motorblocket, ehuru på en därmed vibrationskopplad maskindel (samlingsväxeln VX), vilket har visat sig fördelaktigt vid kartläggning av tändninge- sekvensen genom att vissa störande signalkomponenter härigenom försvinner.The sensor used to monitor the ignition sequence is thus placed at a distance from the engine block, although on a thus vibration-coupled machine part (assembly gear VX), which has been shown to be beneficial in mapping ignition the sequence by thereby interfering with certain signal components disappears.
De bada sensorerna A1,...,AN resp. B1,...,BN är anslutna till var sin ingång hos en mikroprocessor 1 via var sin förstärkare 2A resp. 2B och en A/D-omvandlare 3A resp. en pulsformare 3B. En 10 15 20 30 35 3 -- 461 291 indikeringsanordning 4, exempelvis en bildskärm, är kopplad till en utgång hos mikroprocessorn 1. I stället för enbart en bild- skärm eller annan indikerande anordning kan givetvis en dator- terminal eller persondator användas för dubbelriktad kommunika- tion med mikroprocessorn 1.The two sensors A1, ..., AN resp. B1, ..., BN are connected to each input of a microprocessor 1 via each amplifier 2A resp. 2B and an A / D converter 3A resp. a pulse shaper 3B. One 10 15 20 30 35 3 - 461 291 display device 4, for example a monitor, is connected an output of the microprocessor 1. Instead of just an image screen or other indicating device, a computer terminal or personal computer can be used for bidirectional communication with the microprocessor 1.
Vibratíonssignalen fran respektive sensor A1,...,AN samples, varvid samplingen påbörjas vid erhållande av en triggsignal fràn sensorn B1,...,BN, och varje samplat, digitaliserat amplitud- värde tillföras mikroprocessorn 1 för konventionell uppbyggnad av ett flertal tidsserier (jämför fig. 2, högre delen). Varje sadan tidsserie motsvarar tvà motorvarv (en period) eller en multipel därav. Pa grundval av dessa tidsserier bildas ett tidsmedelvärde för de olika cylindrarnas tândningsögonblick i tändningssekvensen. Dessa tidsmedelvärden bildar tillsammans en karakteristisk vibrations- eller tändningssekvena för en period.The vibration signal from the respective sensor A1, ..., AN samples, wherein the sampling is started when a trigger signal is received from the sensor B1, ..., BN, and each sampled, digitized amplitude value is added to the microprocessor 1 for conventional construction of a number of time series (compare Fig. 2, the higher part). Each such a time series corresponds to two engine revolutions (one period) or one multiple thereof. On the basis of these time series, one is formed time average value for the moment of ignition of the different cylinders in the ignition sequence. These time averages together form one characteristic vibration or ignition sequence for a period.
Emellertid varierar tändningsögonblicken för varje dieselmotor- cylinder tämligen kraftigt, varför det är svart att pa detta sätt få fram en representetiv karakteristisk vibrationssekvens.However, the ignition moments for each diesel engine vary. cylinder quite powerful, which is why it is black on this way to produce a representative characteristic vibration sequence.
Enligt uppfinningen kan den karakteristiska vibrationssekvensen förbättras avsevärt genom ett man dessutom omvandlar vibratione- signalen fran tidsdomän till frekvensdomân (se vänstra delen av fig. 2). Sålunda sker i detta fall sampling utan någon trigg- puls, varvid tidsserier uppbygges och dessa tidsserier omvandlas genom Fourier-transformering (FFT = Fast Fourier Transform) för bildande av ett karakteristiskt frekvensspektrum. Härvid användes ett frekvensomràde som väsentligen motsvarar motorvarv- talet multiplicerat med antalet cylindrar i respektive motor, således för en 10-cylindrig motor ca 10-15 ggr motorvarvtalet.According to the invention, the characteristic vibration sequence can significantly improved by a man also converting vibration the signal from time domain to frequency domain (see left part of Fig. 2). Thus, in this case, sampling takes place without any trigger pulse, whereby time series are built up and these time series are converted by Fourier transform (FFT = Fast Fourier Transform) for formation of a characteristic frequency spectrum. Hereby used a frequency range that substantially corresponds to the engine speed the number multiplied by the number of cylinders in each engine, thus for a 10-cylinder engine about 10-15 times the engine speed.
Tidsskillnader mellan olika tändningar i tändningesekvensen motsvarar toppar i frekvensspektrum. En topp vid frekvensen f har en momentan niva, som är proportionell mot styrkan (ampli- tuden) i de tändningar som motsvarar tidsskillnaden ti+1-ti = 1/f, där ti och ti+1 är tva pà varandra följande tändningstid- punkter. 10 15 20 461 291 4 -- I ett idealfall, där endast ett eller tva tidsintervall förekom- mer mellan tändningarna, uppvisar frekvensspektrum endast en eller tva toppar. Om tändningstidpunkterna avviker periodiskt fran de teoretiska, kommer frekvensspektrum att innehålla flera toppar. I extremfallet, da alla tidsintervall mellan tändningar- na är olika, uppkommer lika manga toppar som antalet cylindrar, dvs. 10 toppar vid en 10-cylindrig motor. Också toppar, som motsvarar tidsskillnaderna mellan tändningar som inte följer direkt pa varandra, t.ek. ti+2-ti, kommer att finnas i frekvens- spektrum, fast vid lägre frekvenser.Time differences between different ignitions in the ignition sequence corresponds to peaks in the frequency spectrum. A peak at the frequency f has an instantaneous level, which is proportional to the strength (ampli- tuden) in the ignitions corresponding to the time difference ti + 1-ti = 1 / f, where ti and ti + 1 are two consecutive ignition times. points. 10 15 20 461 291 4 - In an ideal case, where only one or two time intervals occur, more between the ignitions, the frequency spectrum has only one or two peaks. If the ignition times deviate periodically from the theoretical ones, the frequency spectrum will contain several peaks. In the extreme case, since all time intervals between ignition are different, there are as many peaks as the number of cylinders, i.e. 10 tops on a 10-cylinder engine. Also tops, like corresponds to the time differences between ignitions that do not follow directly on each other, t.ek. ti + 2-ti, will be in the frequency spectrum, fixed at lower frequencies.
De sålunda beräknade topparna i frekvensspektrum kan ateromvand- las till tändningsíntervall uttryckta i delar av motorns period eller arbetscykel, eller i grader. Denna ateromvandling kan göras särskilt exakt, om man samtidigt mäter motorvarvtalet, lämpligen med en särskild givare C på tillhörande motoraxel.The peaks in the frequency spectrum thus calculated can be read to ignition intervals expressed in parts of the engine period or work cycle, or in degrees. This conversion can be made particularly accurate, if at the same time the engine speed is measured, preferably with a special sensor C on the associated motor shaft.
De mindre noggranna mätningarna genom medelvärdesbildning av de triggade tidsserierna kan användas för identifiering av de olika cylindrarna i de fran frekvensspektrum àteromvandlade tidsinter- vallen, sa att en korrigerad, karakteristisk tändningssekvens kan bestämmas.The less accurate measurements by averaging the triggered time series can be used to identify the different ones the cylinders in the frequency-converted time intervals from the frequency spectrum embankment, said that a corrected, characteristic ignition sequence can be determined.
Denna korrigerade tändningssekvens, för var och en av dieselmo- torerna, kan fortlöpande visas pa bildskärmen 4, exempelvis i form av ett polärdiagram. f!!This corrected ignition sequence, for each of the diesel engines can be continuously displayed on the screen 4, for example in in the form of a polar diagram. f !!
Claims (11)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8804663A SE461291B (en) | 1988-12-27 | 1988-12-27 | MADE TO MONITOR PERIODIC VIBRATIONS OF A MACHINE EQUIPMENT |
PCT/SE1989/000706 WO1990007645A1 (en) | 1988-12-27 | 1989-11-30 | A method of monitoring machine vibrations |
AU48192/90A AU4819290A (en) | 1988-12-27 | 1989-11-30 | A method of monitoring machine vibrations |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8804663A SE461291B (en) | 1988-12-27 | 1988-12-27 | MADE TO MONITOR PERIODIC VIBRATIONS OF A MACHINE EQUIPMENT |
Publications (3)
Publication Number | Publication Date |
---|---|
SE8804663A SE8804663A (en) | 1988-12-27 |
SE8804663D0 SE8804663D0 (en) | 1988-12-27 |
SE461291B true SE461291B (en) | 1990-01-29 |
Family
ID=20374334
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
SE8804663A SE461291B (en) | 1988-12-27 | 1988-12-27 | MADE TO MONITOR PERIODIC VIBRATIONS OF A MACHINE EQUIPMENT |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU4819290A (en) |
SE (1) | SE461291B (en) |
WO (1) | WO1990007645A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1161656A1 (en) * | 1999-03-13 | 2001-12-12 | Textron Systems Corporation | Sensor plug and method and apparatus for determining an amount of oil in a device |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2190198A (en) * | 1986-04-28 | 1987-11-11 | Vipac Pty Ltd | Vibrational analysis system for a machine |
-
1988
- 1988-12-27 SE SE8804663A patent/SE461291B/en not_active IP Right Cessation
-
1989
- 1989-11-30 WO PCT/SE1989/000706 patent/WO1990007645A1/en unknown
- 1989-11-30 AU AU48192/90A patent/AU4819290A/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
AU4819290A (en) | 1990-08-01 |
WO1990007645A1 (en) | 1990-07-12 |
SE8804663A (en) | 1988-12-27 |
SE8804663D0 (en) | 1988-12-27 |
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