Chapter 9 - Vibration and Noise

Abstract

This chapter explores vibration and noise in relation to engine testing. Vibration is considered in this chapter with particular reference to the design and operation of engine test facilities, engine mountings, and the isolation of engine-induced disturbances. Almost always the engine itself is the only significant source of vibration and noise in the engine test cell. Secondary sources such as the ventilation system, pumps, and circulation systems or the dynamometer are usually swamped by the effects of the engine. The chapter discusses the fundamentals of vibration and outlines its sources. The practical considerations in the design of engine and test bed mountings are discussed in addition to noise and its fundamentals. The theory of noise generation and control is considered and an account is given of the particular problems involved in the design of anechoic cells. Moreover, the chapter explains the testing of engines and vehicles for noise, vibration, and harshness (NVH) that forms a substantial element of vehicle development program.