Process for measuring the cetane number of supply fuels for diesel engines and apparatus for performing this process
AssigneeElf Antar France
InventorsJoseph Cellier, Guy Mille, Alex Mottas
Life of this patent
Estimating the term…
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.
Claims9
Process for measuring a value of a cetane number of a supply fuel for diesel engines by comparison with a known value of a cetane number of at least one reference fuel, said supply and reference fuels respectively having autoignition delays, said processes consisting of using a measurement diesel engine rotating at a constant speed and successively supplied by said reference fuel and said supply fuel, said measurement engine having a constant compression ratio and a constant injection advance, characterized in that said process consists of calculating the cetane number of the supply fuel based on the value of the cetane number of the reference fuel and the respectively measured values of the autoignition delays of the reference fuel and the supply fuel.
Apparatus for measuring a cetane number of a supply fuel for diesel engines comprising:
- a measuring diesel engine rotating at a constant speed and supplied at a constant flow rate, with a predetermined injection advance or lead, while successively receiving said supply fuel and at least one reference fuel having a known cetane number, said supply and reference fuels respectively having autoignition delays,
- means for successively supplying the measuring engine with the reference fuel and the supply fuel,
- a sensor for detecting each fuel injection time into the engine,
- a sensor for measuring pressure of a combustion chamber of the engine and supplying a pressure measurement signal on an output,
- means for processing the pressure measurement signal for said reference fuel and for said supply fuel and processing a value of a cetane number of the reference fuel in order to calculate a value of the cetane number of the supply fuel, characterized in that the processing means comprises:
- a circuit for detecting a pressure peak, connected to the output of the pressure sensor, in order to detect in the pressure measurement signal the time at which a pressure peak appears which corresponds to an autoignition for the reference fuel and for the supply fuel, following the injection time,
- a measuring circuit connected to an output of the injection sensor and to an output of the a pressure peak detection circuit in order to measure the delays separating the injection and pressure peak appearance times, for each of the reference and supply fuels, said delays respectively corresponding to the autoignition delays of said fuels
- a processing unit connected to an output of the measuring circuit and to storage means for calculating the value of the cetane number of the supply fuel based on the cetane numbers of the reference fuel and autoignition delays of the reference and supply fuels.
Dependencies are inferred from the claim text.