Noise Measurements of Electric In-Tank Fuel Pumps 870982
In this report, several types of noise measurement data are compared to subjective evaluations for interior vehicle noise generated by the in-tank electric fuel pumps. The various noise measurements are discussed and data is presented to show the correlation of each measurement type to a group subjective rating. Additionally, vibration data is evaluated to define a specification for acceptance of the pump assembly and to help identify problem areas for pumps not meeting this specification.
In recent years, automobile companies have made many improvements to reduce the interior noise levels of their vehicles. This reduction of interior ambient noise has revealed other acoustical problems which were masked and not apparent as early as five years ago. Instrument cluster squeaks and rattles, mechanical or electrical speedometers and (or) gages and in-tank electric fuel pumps are some examples of these acoustical generators which have of late been receiving attention. This paper addresses some of the problems associated with the measurement of noise generated by electric in-tank fuel pumps and suggests methods of noise measurement and production sorting by correlating vibration data to in-vehicle sound pressure measurements.
High performance engines which make use of throttle body injection (TBI) and multiport fuel injection (MPFI) require that fuel pumps deliver high pressure and (or) high flow rates of fuel. In order to meet these performance requirements, fuel pumps have been designed to be more efficient and to operate at higher speeds. The inefficient work of the pump is dissipated in the form of heat, vibration and radiated sound. Noise and vibration generated by the in-tank fuel pump is additionally burdened by the drum-like effect of the fuel tank. This additional sound appears to vary with the fuel level. Subjective ratings are complicated by the physiological and psychological responses not only between people but also for the same person at different times. (1) Moreover, noise generated by a fuel pump is complex and contains a variety of spectra generated by a great many structural components. Noise generated by components in one pump assembly may be perceived differently from noise which is generated by components in a different pump assembly. Therefore, a valid and reliable method to measure this subjective noise and to identify the components generating that noise needs to be developed.