Patent ID: 6298838
Filing Date: 2001-10-09
Classification: F02B,F02D,Y02T

Abstract:
A method for ethanol content learning based on engine roughness comprising the steps of:establishing a trigger threshold based on engine speed and manifold pressure;establishing a fix threshold based on engine speed and manifold pressure;obtaining a first measured engine roughness;incrementing fuel delivery by a first ethanol amount if a first measured roughness is greater than said trigger threshold;obtaining a second measured engine roughness after incrementing fuel delivery by said first ethanol amount;decrementing fuel delivery by said first ethanol amount if said second measured roughness is greater than said trigger threshold;incrementing fuel delivery by a second ethanol amount if said second measured roughness is not greater than said trigger threshold but greater than said fix threshold;obtaining a third measured roughness after incrementing fuel delivery by a second ethanol amount; anddecrementing said fuel delivery by said second ethanol amount if said third measured roughness is greater than said trigger threshold.