[en] Several studies of heavy ion reactions have been made recently where light particle-heavy fragment coincidence techniques have been employed to explore the existence of non-equilibrium phenomena. We report the results obtained on the ₁₄N + ₂₇Al system at 100 MeV incident energy. The measurements have been performed at the isochronous cyclotron of the Institut des Sciences Nucleaires at Grenoble. We shall give the schematic feature of what we mean by preequilibrium emission. The experimental data and their analysis will be split in three parts: reaction mechanisms observed in N + Al system, preequilibrium emission in fusion and deep inelastic process