A Noise Testing System Used For Engine Based On Virtual Instrument

This thesis discusses detail about how to research a noise testing system for automobile engine based on virtual instrument (shortly: VI).Firstly this paper analyses what the automobile engine noise make and how the noise work. The noise of engine includes the noise of surface and the noise of eradiating to atmosphere directly. And the noise of surface make of mechanical noise and the noise of combustion. And the thesis discusses how to test the whole noise of engine and how to find good ways to control the noise of engine.Secondly this paper gives a way to use the VI to finish the testing work. And the paper discusses how to research the hardware and software of this engine noise testing VI. About the hardware, the paper advises using microphone as sound sensor, researches signal magnify circuit and chooses the feat DAQ Card: bring forward that using the Sound Card as simply DAQ Card. About the software, this paper suggests that using LabVIEW, which is used broadly in CAT field by the American Company-NI, as the basic software program.At last, this paper records the test about the noise of some generator engine under zero' s or 400W s load via the VI and the Spectralab software. The test process proves that this noise testing Virtual Instrument can fit for testing the noise of automobile engine and for analyzing what engine' s noise include. In the end, this thesis lodges a new concept by researching VI to testing other function of engine not only it' s noise.