Cyclic variability of pulsed spray vapor fields

 A two wavelength extinction technique is used to quantitatively measure the temporal fuel vapor field produced by pulsed automotive fuel injectors. Line-of-sight measurements are spatially deconvoluted to yield a picture of the overall, cycle-averaged, radial vapor concentration profiles. Vapor measurements are also given for single, consecutive, injection pulses, showing cycle-to-cycle variations in the vapor field. Methods to characterize the cyclic variability in the vapor field of a pulsed spray are discussed. As an illustrative example, the differences between an air assist and a non-air assist injector are shown as a function of duty cycle and axial location. Received: 11 August 1997/Accepted: 10 February 1998