Time-resolved emission spectroscopy for the combustion analysis of series production engines

Abstract

This paper presents a device that detects light emerging from the combustion inside a series production automotive engine. Simulta- neous time and wavelength resolution is achieved by this system and it can be applied in a simple manner to either diesel or spark ignition (SI) engines without any geometrical modification of the combustion cham- ber. An optical probe is inserted into spark plug or glow plug. A fiber is connected to the probe and leads the light to a spectrograph, which provides spectral analysis in the UV and visible wavelength ranges. An intensified streak camera with time resolution in the microsecond range completes the detection unit. This measuring system enables time- resolved emission spectroscopy applied to the light emitted during the combustion in a series production engine. Time-resolved emission spec- tra are presented from both a diesel and an SI engine. The time behavior of the internal temperature in a diesel engine combustion chamber and its dependence on engine speed and load are measured with this setup using a multiple two-color method. In an SI engine, the time behavior of the emissions of specific molecules or radicals is detected. Thus, differ- ences in the combustion process are demonstrated to be caused by operation with different fuels. © 1997 Society of Photo-Optical Instrumentation En- gineers. (S0091-3286(97)02804-3) Subject terms: time-resolved emission spectroscopy; streak camera; series pro- duction engine; continuous radiation at diesel engine; radical radiation at spark ignition engine; time behavior.