LASER TOOLS FOR DIESEL ENGINE DIAGNOSIS. PAPER C48/85

Two portable laser instruments are described which allow the engineer to simply "stand and point" laser beams at a target surface in order to obtain a measurement of time resolved vibration velocity. The first supplements the accelerometer and measures normal surface velocity but offers the advantage of non-contact measurement. Its use is demonstrated in detecting reduced nozzle pressures in fuel injectors. The second instrument is a laser torsional vibrometer which measures torsional oscillations of rotating machinery parts and in particular crankshaft oscillation. Comparisons are made with the more standard technique which utilises a slotted disc. The new instrument provides advantages of non-contact measurement, insensitivity to shaft radial motion and the ability to measure oscillations of shafts of arbitrary cross-section. For the covering abstract of the conference see IRRD 287559. (Author/TRRL)