Patent ID: 6176222
Filing Date: 2001-01-23
Classification: F02D,F02M

Abstract:
A control method for an internal combustion engine in which fuel vapor delivered to an engine cylinder in a given engine cycle is generated in part from liquid fuel delivered by injection for that cycle and in part from puddled liquid fuel from prior injections, the control method comprising the steps of:modeling the injected and puddled liquid fuel as comprising a plurality of components of varying volatility, each component having a characteristic evaporative time constant;estimating a mass fraction of each component of the injected liquid fuel and a mass of each component of the puddled liquid fuel;determining a first quantity of fuel vapor that will be collectively generated in the given engine cycle from said plurality of components of the puddled liquid fuel, based on said evaporative time constants and the estimated masses of puddled liquid fuel;determining a desired quantity of fuel vapor for delivery to the engine cylinder;determining a second quantity of fuel vapor to be generated by injected liquid fuel according to a difference between said desired quantity of fuel vapor and said first quantity of fuel vapor;determining, based on said mass fractions and evaporative time constants, a commanded quantity of injected liquid fuel such that a fuel vapor quantity generated by such liquid fuel in the given engine cycle equals said second quantity of fuel vapor; andinjecting liquid fuel into said engine in accordance with said commanded quantity.