Patent ID: 7533660
Filing Date: 2009-05-19
Classification: F02D,Y02T

Abstract:
1. A method for recognising the fuel type in a diesel engine ignited by compression of mixture; the method comprising the steps of: determining a stoichiometric air/fuel ratio of the last type of fuel used; determining a quantity of fresh air fed to a number of cylinders of the engine; determining a quantity of fuel injected in the cylinders; determining the theoretical air/fuel ratio of combustion according to the quantity of fresh air fed to cylinders, according to the quantity of fuel injected into cylinders, and according to the stoichiometric air/fuel ratio of the last type of fuel used; determining an actual air/fuel ratio of combustion; comparing the theoretical air/fuel ratio with the actual air/fuel ratio; and recognising the fuel type actually used according to the comparison between the theoretical air/fuel ratio and the actual air/fuel ratio so that if the difference between the theoretical air/fuel ratio and the actual air/fuel ratio is lower than a first threshold value, then it is assumed that the type of fuel actually used is identical to the last type of fuel used, and if the difference between the theoretical air/fuel ratio and the actual air/fuel ratio is higher than the first threshold value, then it is assumed that the type of fuel actually used is different from the last type of fuel used.