Measurement of Fuel Injection Pump Sound Power Using Acoustic Intensity Techniques 930200
Increasingly severe noise legislation and customer expectations for improved vehicle refinement continue to require fuel injection equipment manufacturers to reduce the noise generated by injection pumps. The measurement of injection pump noise or, more recently, sound power level has hitherto been carried out in anechoic or semi-anechoic chambers using purpose built quiet drive rigs which have themselves required continual quietening in order to allow accurate measurements to be made.
The accuracy and speed of the measurements were improved some years ago with the development of the microcomputer based Lucas-CEL sound power analysis system. However, recent advances in acoustic intensity technology due to the ready availability of low-cost processing power has led to a re-evaluation of the measurement of pump sound power. A personal computer based system using a combination of proprietary and in-house software and hardware has been developed and applied to measure pump sound power level.
This paper compares results obtained using the new system with those obtained with the old system, and discusses the relative advantages and disadvantages of the two systems. The acoustic intensity method offers some additional benefits, which are discussed and illustrated with test results.