Method for optimizing the operation of a thermal engine by determining the proportion of oxygenated compounds in the fuel

A method for optimising the operation of a thermal engine having combustion parameters controlled by an electronic housing and at least one engine mapping, characterised in that the method comprises:

• a step of carrying out a near-infrared spectroscopic analysis of a bio-fuel containing a mixture of alcohols and/or ethers and/or water in order to determine the proportion of water and of at least one other oxygenated compound of the alcohol and/or ether type contained in the bio-fuel;
• and
• a step of selecting and/or modifying said mapping on the basis of the result of said step of analysis and determination in order to optimise the operation of the thermal engine;
• wherein the step of carrying out a near-infrared spectroscopic analysis of the bio-fuel includes a phase of correction as a function of the multiple overlapping of characteristic bands associated with bonds of the oxygen atoms present in the bio-fuel, wherein the bonds of the oxygen atoms present in the bio-fuel are R—O—H bonds present in primary alcohols and/or C—O—C bonds present in esters and/or H—O—H bonds present in water;
• and
• wherein the step of carrying out a near-infrared spectroscopic analysis of the bio-fuel also includes a phase of correction as a function of a measurement of the bio-fuel temperature from at least one temperature detector.