Diesel Engine Health: Laser Diagnostics

This paper describes two simple laser instruments which the automotive engineer can use in vibrational studies of diesel engines. The first is a ‘normal surface velocity’ instrument which the engineer can hand hold and simply ‘point’ at the target surface for measurement. Field tests have shown it to be quick and easy to use with excellent accuracy and reliability. It is a particular time-saver in test cell use where the necessity for many accelerometer fittings is removed. The second is a laser torsional vibrometer which can measure the torsional oscillation of rotating machinery parts. This has shown itself to be superior to the more standard techniques of slotted discs and slip rings, etc. and provides advantages of higher frequency response, greater accuracy and non-contact measurement. Conclusions drawn herald a step forward in measurement techniques and demonstrate the great potential of laser technology in heavy engineering applications.