Method and Device for Detecting the Cetane Number

A method for detecting the cetane number of the fuel used by a direct-injection diesel engine equipped with a turbocharger comprises the steps of operating the diesel engine with at least two different delays of the start of injection with respect to a nominal start of injection, measuring the turbocharger speed depending on the delay, and determining the cetane number from the variation of the turbocharger speed with the delay. The invention also concerns a device for detecting the cetane number of the fuel used by a direct-injection diesel engine equipped with a turbocharger.