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Engine Test

RotasPro Noise Analysis. Engine Test. Discom Industrial Measurement Inc. Cabin noise. Base System. Engines, Gearboxes and Components. APAS-II. ROTAS-Mobil. MESAM 4.

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Engine Test

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  1. RotasPro Noise Analysis Engine Test

  2. Discom Industrial Measurement Inc. Cabin noise Base System Engines, Gearboxes and Components APAS-II ROTAS-Mobil MESAM 4 The company was founded in 1985. It is situated in Göttingen in the heart of Germany. Since 1989 the main product are measurement system for the acoustical quality analysis. There are 18 employees and more than 500 test systems deployed. Base system are ROTAS and MESAM-4 (a joint development with DaimlerChrysler). Build on top of them are APAS for the cabin noise analysis, ROTAS-GP for the analysis of gearboxes, transmissions and engines, ROTAS-ZP for the single gear test, ROTAS-TMO for the test of tapered roller bearings.

  3. Discom: Customers and Applications American Axle, USA Front and Rear Axles, 5 Systems Jatco, Japan CVT Transmissions GM, USA, Opel D and A Gearboxes and Axle Testers, Gear Testers 44 Systems Bentley, UK Cabin Noise Analysis APAS, 2 Systems Borg-Warner, USA,UK Transmissions und Axles 11 Systems Renault, Peugeot Transmissions, Gear Testers 11 Systems DaimlerChrysler D, US Cooperation MESAM4, gearboxes, transmissions and engines. 48 Systems Robert Bosch Starters, injection pumps, production database 6 Systems SKF D, USA, India, Ukraine Tapered Roller Bearings, 35 Systems Eaton, Br and India Manual transmissions, mobil system SAIC Shanghai Automobile Internatiol Corp. Gearboxes test systems, 5 Systems First Automobile Works, China Gearboxes 2 Systems Skoda, Cz Gearboxes, 7 Systems Fiat, Iveco, Tata, It, Brazil, India Manual Transmissions 20 Systems SFT, Magna Stey Powertrain Axles and gearboxes 28 Systems Ford, D Gear Testers 4 Systems Tongil, Korea Axles, Durability test Stand, 1 System Graziano, ItalyGearboxes and Axles for Audi, Aston Martin, Ferrari, Lamborghini, Maserrati Volkswagen D, ES, SA,AR, China,B,SK,BR Gearboxes, Transmissions, Gear Testers, Cabin Noise Production Database, 178 Systems Getrag, USA Sc, Single Flank Gear Tester for Cummins Engine Gears with Tors. Acceleration Cummins ZF D Gear Testers 4 Systems Hyundai, Korea Gear tester 2 Systems

  4. Rotas NVH Testing • End of line test with vehicle correlation and the ability to find production errors • Separation of noise components from shafts with synchronous averaging • Calibrated evaluation for comparison of the production process with car experiences • Simultaneous measurement and evaluation of all transmission order components • Recognition of nicks on gears and bearings • Trainable system in combination with fixed limits • Test results stored in central data base • Intranet evaluation of test results for groups of test benches

  5. ROTAS Test Stand Configuration Parameter- und Limit Database Sensors Test Stand Control Rotas Analysis Program Result Database Archives, SQL-DB Presentation Web Statistics

  6. Rotas Analyzers TAS USB Measurement frontend. 10 analog channels, 4 speed inputs, D/A monitor outputs. Mobile system with USB power for 5 ICP sensors 19”-Industrial PC. TAS Frontend RAID system Dual Core and I7 CPUs Panel with IPC and TAS Frontend. AC and UPS build into panel

  7. BKS03 Accelerometer The BKS03 has a linear frequency range of up to 10 kHz and can be used to pick up the NVH signal also from unfinished surfaces

  8. Order Analysis Exact order analysis is accomplished by generating of the same amount of samples per revolution of a part, independent of its revolutionary speed. Digital resampling allows for the processing of 3 to 5 shafts of a transmission. From this resampled time domain signal, spectra evaluation produces order components. These are the amplitudes of sine components, which are cyclic with the revolution of the part Input One rev Input One rev Input One rev Constant number of samples per revolution

  9. Revolution Synchronous Transmission Analysis The transmission noise is the sum of the noise originating from the individual mechanical components. For the gear noise components, the individual sources can be isolated by the transmission ratio. Input Shaft Interm. Shaft Output Shaft Synchronous order analysis: The signals are acquired synchronous to the inner shafts. Acoustical Stroboscope Input Shaft Interm. Shaft Output Shaft

  10. Synchronous Averaging Signal For every shaft, averaging is performed synchronous to its revolution. Signal components of the synchronousshaft are enhanced, other noise components are attenuated. One shaft is shown. Rotas can do the processing for 3 to 5 shafts simultaneously. Usually, only one sensor is needed. The synchronization can be done for inner shafts, for which only the transmission ration is known. + Background + Signal + Background + Signal + Background Summe * 1/n = Average: Signal enhanced

  11. Synchronous Averaging Cylinder Noise peaks are shown in the synchronous channel that is synched with the respective shaft. A valuable nick detection is based on the Crest value: Crest = Peak value/RMS value 9 1 2 3 4 5 6 7 8 10 11 12 12 Cylinder Engine, 700 UPM, 1 Rev Cam Shaft

  12. dBg VGW 105 VGW-lim 90 75 60 45 10 20 30 40 50 60 70 80 90 Ord Evaluation of Order Spectra The order spectra of the synchronous channels and of the mix channel are compared with a limit curve. Every order of the limit curve has an underlying error code. This error code is generated from transmission ratios in a semiautomatic fashion. If the limit curve is exceeded, the error code gives rise to an error message in plain text. The limit curves consist of portions, which are generated by a learning process and of portions which are set to fixed values. The learn rnode is used for those spectral portions, where there are results from driving experiments available yet. Generally this holds true for tooth spacing problems, ghost orders and bearing noise (in the mix channel). Fixed limits are adopted from driving experiments, usually for the gear mesh and for the side bands.

  13. Spectral Limits Hats for gear mesh orders and their side bands Limit curve from Average + Offset + n times standard deviation. Overridden by minimum and maximum polygons and by the fixed hats.

  14. Learning What is learned Learning methods For all measurements, the following statistical properties are computed: Average (AV) und Standard deviation (STD) From these numbers, a limit L is generated according to L = AV + Offset + n* STD. The offset and the multiplier of the standard deviation is selectable. For spectral measures, an offset of 5 dB and a std-factor of 3 is normally used. Maximum and minimum values set upper and lower bounds for the limit L. A new learn consist of a base learn (usually 5 units), where all units are accepted that are below maximum polygons and below hats. The base learn is followed by an additional learning (usually 100 units). Here every unit is evaluated against the already established limit curves. Only error free units will be added to the learning sample. Another available choice consists of a indefinite learn process with a selectable time constant. During the whole learning process, the fixed limits apply. This assures, that all known data (like limits from car experiments) will be used as a guidance during the process.

  15. Order spectrograms Order spectrograms are recorded for the engine vibration signal. From these order tracks for arbitrary orders and order spectra for arbitrary speeds can be generated: 2) Order spectrum at 2241 RPM Order track for the 65. order 1) Ordnungs-Spektrogramm 4. Gang Zug

  16. Order Tracking • The critical noise sources in a car are usually the gear mesh orders and their sidebands. • These noise sources are highly speed dependent. Detailed speed dependent evaluation uses the track of mesh orders and sidebands over speed. • The gear mesh H1 base order and its harmonics are tracked over speed and compared with speed dependet limit curves. • The track form depends on torque, drive/coast and on the resonances within the gearbox and the test stand. • Within speed bands, average and maximum amplitudes can be evaluated and compared to limits. The single values are ideal for statistical analysis over time. Speed band Tracked Value Curve 1Curve 2 H1 Max Bd1 79.1 dB75.5 dB H1 Aver Bd1 76.2 dB71.9 dB

  17. Synchronous Angular Spectrogram 0.35 g Rev 400 300 200 100 0 0.05 g 0 45 90 135 180 225 270 315 Short-time spectra are computed over the revolution of the engine. Several spectra are averaged and indicate spectral abnormalties at certain angles. Nicks and Ticks of all kinds can be identified with this method Ordnung Grad NW

  18. Hydraulic Valve Defect A defective hydraulic valve is shown in the angular spectrum for two different positions of accelerometers on the cylinder head Rev Synchronous Spectrogram Rev Synchronous Spectrogram Accel back right Accel front left Orders -> Modulation Spectrum Orders -> Orders -> Camshaft Degrees -> Camshaft Degrees ->

  19. Measurement Report A protocol is generated for every unit. It holds information about unit type, serial number, time of measurement and defect report. There are three kinds of report: Short:: serial numbers only for good units, defect report for failing units. Normal: Report line for every unit Long: All measurement values in tabular form. Around 300 measurement results are stored in a protocol database for statistical evaluation. 5000 units use about 20 Mbyte of disk space. The test stand control system can request several protocol variants for own recording purposes.

  20. Server Management of Multiple Test Benches Test Benches Parameter Setting and Statistical Evaluation Data Parameter PC with Internet Explorer Intranet Central archive of test results Parameter setting and statistical evaluation from every PC with intranet access.

  21. Rotas Data Flow Work Group PC has presentation software installed Can use Intranet statistcis via Internet Explorer Rotas Analyzer Test Stand Measurement Archives Rotas Presentation Measurement Database Intranet Statistics Work Group PC Server or Test Stand

  22. Order Spectra 618CKA20013288 29.Feb'2008,07:08:09 Unit x multiple runs in pink. First run highlighted in blue. GM6R Silao Stand 2 Type 8CKA [80] Serial 618CKA20013288 29.Feb'2008,07:08:09 Transmission NOK *** -------------------------------------------------------------------------------- code errortext gear value limit avg u O/Tp ch 16718 Transmission: Order loud in 6-Coast 6-sC 92.3/ 90.1/ 66.7 dBg 57.00 R1 16718 Transmission: Order loud in 6-Coast 6-sC 96.4/ 92.6/ 76.8 dBg 53.00 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 93.5/ 93.4/ 77.5 dBg 54.50 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 96.5/ 95.5/ 77.7 dBg 76.50 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 93.8/ 88.1/ 72.1 dBg 133.00 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 89.5/ 88.7/ 72.6 dBg 135.50 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 89.1/ 89.0/ 72.8 dBg 136.50 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 90.8/ 89.1/ 74.4 dBg 147.00 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 93.2/ 92.8/ 77.0 dBg 166.00 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 92.7/ 92.7/ 76.7 dBg 176.00 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 95.1/ 91.2/ 75.4 dBg 198.50 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 99.0/ 95.1/ 78.4 dBg 233.00 MixR 16718 Transmission: Order loud in 6-Coast 6-sC 96.3/ 95.2/ 78.4 dBg 234.50 MixR

  23. Spectral Statistics Order spectra of production units can be displayed in Campbell or in 3-D graphs. Cuts in the order or in the unit direction show order amplitude versus units or the spectrum of one unit. The pictures show the order spectra of 300 production units. A ghost order of 118 is present in the first 40 units tested.

  24. Order Tracks During the ramps, spectral components are evaluated over the speed. Usually, the main gear mesh orders and their harmonics are tracked. In addition, energy in order bands may be tracked as well. Track limits (shown in red) can be self learned or set manually.

  25. Complete Data Report of a single Unit Macro controlled display of archived data. The database is used for searching of serial numbers, test results etc. Then the presentation software displays a full measurement report Sensor Group 1

  26. Intranet Statistics The information of the SQL measurement database can be retrieved via the intranet. The production results and the measurements can be seen online. An arbitrary time interval can be selected for the analysis.

  27. Statistical Evaulation for Types and Benches Test results The evaluation can be done over gearbox types or over test benches. Any time interval can be specified.

  28. Measurement Statistics and Bench Comparison Over 300 individual measurement results can be evaluated. The comparison of test benches makes it easy to administer large production facilities.

  29. Reject Analysis, Top n and Type Specific The results are shown both in tabular and in graphical form

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