METHOD, APPARATUS AND PROGRAM FOR ESTIMATING ALCOHOL CONCENTRATION IN ALCOHOL FUEL MIXTURE SUPPLIED TO INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a method, an apparatus and a program for efficiently and surely estimating an alcohol concentration in an alcohol fuel mixture supplied to an internal combustion engine.SOLUTION: The operation of the internal combustion engine supplied with the alcohol fuel mixture is controlled in a stoichiometric condition. A first parameter is determined (S426) on the basis of a signal from a pressure sensor sensing a pressure inside a combustion chamber of the internal combustion engine controlled in the stoichiometric condition. An alcohol concentration of the alcohol fuel mixture is determined on the basis of the determined first parameter and on the basis of a prestored relationship between the first parameter and the alcohol concentration of the alcohol fuel mixture.