Two-Dimensional Temperature Measurements in an SI Engine Using Two-Line Tracer LIF

Transient two-dimensional temperature distributions in the compression stroke and in the unburned end-gas of an SI engine were measured employing laser-induced fluorescence (LIF) of a fuel marker that possesses strongly temperature-dependent spectroscopic properties. The use of two different excitation wavelengths simplifies the otherwise complicated relation between LIF signal intensity and system parameters. The temperature fields obtained in this manner can be used to correct measured tracer-LIF maps and thus help to determine fuel distributions. Averaged temperature fields are compared to model calculations based on a homogeneous reactor assumption.