Laser diagnostics of diesel engines

Features and techniques of laser diagnostics for characterizing liquid particles, solid particles and molecules in non-reacting and reacting diesel sprays are presented. The extinction method is a line-of-sight measurement and can provide mean diameter of all fuel droplets in a spray, soot concentration in a spray flame averaged along the optical path, and soot diameter in the diesel exhaust. 2-D images of scattering from those particles in a plane irradiated by a laser sheet can provide spatial distribution of particle size and number density if combined with other 2-D imaging techniques. LIF techniques are advantageous diagnostics in imaging fuel vapour, radicals and combustion products in mixture formation and combustion processes.