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Two-dimensional imaging of fuel-vapour concentration by use of LIEF technique during mixture formation process in a DI diesel engine

2002; IOP Publishing; Volume: 13; Issue: 3 Linguagem: Inglês

10.1088/0957-0233/13/3/322

1361-6501

Hajime Fujimoto, Dae Kyung Choi, Yuta Shima, Jiro Senda,

Vehicle emissions and performance

The laser-induced exciplex fluorescence (LIEF) technique, which is based on spectrally resolved two-colour fluorescent emissions, has been applied to an evaporating diesel spray for the simultaneous separation of liquid and vapour phases on the two-dimensional images. The exciplex system is based on the TMPD/naphthalene system proposed by Melton. The temporal and spatial distribution of liquid and vapour phases during the mixture formation process was detected by this technique. In the LIEF technique, the vapour phase is detected by the monomer fluorescence while the liquid phase is tracked by the exciplex fluorescence. It is able to provide quantitative information on the diffusion state for applying the statistical entropy concept. This concept was put into practice in the image sets obtained through LIEF measurement in order to investigate the diffusion process of vapour phase in the evaporating diesel spray. The laser shadowgraph was taken to deduce the effect of turbulent mixing on the ignition. The experiments were conducted in a direct injection diesel engine with optical access required for the two-dimensional laser imaging.