Patent ID: 6079396
Filing Date: 2000-06-27
Classification: F02D

Abstract:
An internal combustion engine air/fuel ratio control method, comprising the steps of:sensing an engine startup operation;sampling an input signal indicating engine speed following the engine startup operation;estimating fuel volatility as a function of engine speed;identifying the estimated fuel volatility as one of a high volatility and a low volatility;modifying a correction value, by (a) increasing the correction value upon identifying the estimated fuel volatility as a low volatility, and (b) decreasing the correction value upon identifying the estimated fuel volatility as a high volatility;correcting an air/fuel ratio control command as a function of the modified correction value; andcontrolling engine air/fuel ratio in accordance with the corrected air/fuel ratio control command to provide for accurate engine air/fuel ratio control over a range of fuel volatilities.