Application of Laser Doppler Anemometry to a Motored Diesel Engine

Some problems associated with applying LDA to the measurement of air motion in the engine’s cylinder are studied experimentally for both the forward and the back scattering technique in a motored diesel engine. The effects of the doppler broadening caused by the velocity gradient and the diameters of the scattering particles are discossed. The decaying process and the structure of the in-cylinder flow field are studied using the measurements of the main flow velocity, the turbulent intensity and macro scales and normalised power spectrum of the turbulence. A comparison measurement is also made between the forward scattering and the back scattering techniques.