Patent ID: 6038917
Filing Date: 2000-03-21
Classification: G01F,G01N

Abstract:
A method for determining a fuel economy of a gasoline powered motor vehicle having an engine, a plurality of fuel injectors and an intake manifold, said method comprising the steps of:determining a nominal fuel flow through said fuel injectors under static pressure conditions;determining an additional quantity of fuel flow through said fuel injectors caused by dynamic pressure transients by determining a pressure drop across said intake manifold;determining a total mass quantity of fuel used for a given period of time by adding said determined nominal fuel flow to said additional quantity of fuel flow to produce a total mass fuel used value;converting said total mass fuel used value to a total fuel used volume value by using an estimated octane value for said fuel and a density of said fuel which is determined by estimating a temperature of said fuel flowing through said injectors based on a temperature of coolant flowing through said engine; andusing said total fuel used volume value to determine an instantaneous fuel economy value.