METHOD TO DETERMINE A CETANE NUMBER OF A FUEL

摘要

A method of determining the cetane number of a fuel in an internal combustion engine comprising, during running of the engine, i) with respect to one cylinder, performing a routine comprising a series of injections wherein for each injection a quantity of fuel is injected into said cylinder, and during said routine varying the angle at which said injections takes place with respect to crankshaft angle; ii) measuring engine speed at intervals during said series of injections and determining values for changes in engine speed consequent to said injections; iii) determining cetane number from a pre-stored relationship relating said cetane number to changes in engine speed consequent to changes in said test injection angle.