END-OF-LINE ACOUSTIC ENGINE TESTING DISCOM Noise Analysis for Engine Test
ACOUSTIC TESTING FOR THE HEART OF THE CAR The engine is the heart of the car. If it isn t working, neither is the car, so end-of-line quality assurance testing is absolutely necessary to prevent bad engines from making it into a finished vehicle. And because the engine can be so costly to fix and replace when there are problems, the key to a cost-effective production line goes beyond that quality assurance; the key is identifying the root cause of the problem. Tracing the failure back to its root cause and mitigating or eliminating problems before they happen not only ensures the overall quality of the engine, it saves time, improves cost-effectiveness and increases production line yield. Innovation in engine testing Immune to the environment getting good, consistent data Continuous learning DISCOM Noise Analysis for An additional benefit of cyclical from testing iterations of a continuously refines Engine Test introduces a new data and synchronous averaging particular engine type and parameters method for detecting pulse noise that saves time and reduces consistent test parameters. This Evaluation limits are generated from engines. Combining angular cost is that background noise is enables Hot and Cold engine by a combination of known cycle information with spectral averaged out of the calculated testing without having to use standards and learned statistics. signatures and rotationally orders. This means that you will specialized software for each Limit learning has two phases: synchronous averaging enables not have to create additional test type. 1. Base learning DISCOM to detect anomalous delays at the test stand while 2. Additional learning noise, associate that noise with the engine under test is isolated For even more data a mechanical error, differentiate from its environment. The system is modular, so it can Base learning begins the the noise from other patterns easily be expanded by adding: learning process with only a and pinpoint the source and Hot and cold Acquisition hardware small number (about five) of cause of the noise. This method of testing is based (including more sensors, test units. In this phase, the on learned test limits set by laser vibrometers, torsional measured value is compared to accelerometers, microphones, the upper boundaries from the CYCLE SPECTROGRAM Short-time spectra are computed over the revolution of the engine. Several spectra are averaged and indicate spectral abnormalities at certain angles. Spectral and timing information is combined. Pulse components of all kinds can be identified with this method. Cylinder head on motor cycle torque and temperature inputs, CAN bus interface) Front ends to accommodate the extra hardware Speed inputs for Crankshaft known standards, which are based on R&D specifications and predictions. By the end of this stage, the preliminary limits are set. Timing Gear, Camshaft Gating The additional learning phase and Ignition and Injector uses a larger production run, signals typically 200 units. Each unit is Custom analysis and tested against the previously evaluation methods established limit values. The data from each unit is added to the
Cycle spectrogram bands can be overlaid to enable limit curves to be self-learned (showing 100 overlaid bands) statistics and used to further fine tune the limit values. This can happen even with full production running and does not require specially prepared units. The learning process can be restarted or extended at any time, including for refining the limits of specific components in the unit, such as single gears, or specific values. So even later in the production phase, the system s limits can be continuously refined. a stand-alone system and to be a part of a greater powertrain measurement environment. The system can learn from its own data and use data from and provide data for related measurements in other test areas, such as gear testing. Mobile tests performed in a completed vehicle can be used to correlate in-cabin data with teststand data, further increasing the accuracy and efficacy of the parameter limits. automatically provides the engine type to be measured and serial number, then begins the test sequence. Each test cycle consists of a number of steps that generate specific results. Test steps can be run in any sequence, or even repeated or omitted. In each test step all measurements applicable for that test step are performed, all limits applied and, if exceeded, applicable text error messages are generated. Know your production The results of every test run, from every test stand in the production line, are collected in a large results database. This database is the anchor point for Web.Pal, an Intranet-based production analysis tool, that highlights current production problems, offers trend analysis, helps refine limits, and closes the loop of continuously enhanced production quality. Part of a learning measurement system DISCOM Noise Analysis for Engine Test is designed both as The end-of-line test sequence All testing is performed under simulated operational conditions. The test stand control
UNIQUE DATA PROCESSING AND ANALYSIS TasAlyser software is the data analysis part of the system. It controls data acquisition and processes the signals. Using rotationally synchronous averaging, this software computes one synchronous analysis channel for each acoustic component and each sensor. Rotationally synchronous averaging: Separates the synchronous channels for order analysis Processes time signals for the detection of defects Processes periodic signals corresponding to the cyclic nature of engines TasAlyser has numerous display capabilities for evaluation and results
SAMPLE MEASUREMENT CYCLE Speed 1500 RPM 1000 RPM Low1 OILP Buildup Low2 OILP OK High1 VVT off High2 VVT on High3 VVT Off Time
www.bksv.com/production-testing DISCOM For the past 20 years, DISCOM has developed and distributed systems for acoustical quality analysis used in end-of-line testing, and these systems are highly respected and used worldwide by companies in and around the automotive industry. Brüel & Kjær acquired DISCOM on July 26, 2016. This acquisition enables Brüel & Kjær to better support its customers by expanding its production quality testing capabilities to end-of-line analysis solutions. Brüel & Kjær also provides networks for DISCOM to better support customers and additional resources to facilitate adaptation to the ever-evolving automotive industry. Brüel & Kjær Sound & Vibration Measurement A/S DK-2850 Nærum Denmark Telephone: +45 77 41 20 00 Fax: +45 45 80 14 05 www.bksv.com info@bksv.com Local representatives and service organizations worldwide Brüel & Kjær DISCOM Neustadt 10-12 37073 Göttingen Germany Telephone: +49 551 54833-0 discom.info@bksv.com BG 1956 11 ËBG-1956---PÎ 06/2017