Abstract: The invention relates to the measuring of the cetane number of fuels supplied to diesel engines. According to the invention, the combustion chamber of a diesel engine for measuring the cetane number of a fuel is decoked by creating, between two measurement cycles, for 80 to 160 seconds, strong turbulence in the gases inside the combustion chamber. The invention finds its application in research laboratories, test laboratories and the units which manufacture these fuels in crude oil processing plants.

Abstract: An apparatus and method for testing and monitoring fuels produced for diesel engines. The cetane number of a supply fuel for a diesel engine is measured based on the value of the cetane number of two reference fuels. The autoignition delay is measured and compared to the delay for the reference fuels. The delay is measured using a diesel engine which operates at a constant speed with a constant volume compression ratio. The sample of the supply fuel may be drawn and tested in a research laboratory or may be used on line during the production of the fuel.