Patent ID: 7761218
Filing Date: 2010-07-20
Classification: F02D,Y02T

Abstract:
1. An air-fuel ratio control method of an engine using an air-fuel ratio control means configured to use an intake air flow rate estimated using an intake pipe pressure value and an engine revolution number, and the engine revolution number, to determine a fuel injection time, and output a fuel-injection signal to an injector to thereby control an air-fuel ratio of a supplied fuel, wherein the engine revolution number is controlled by opening and closing of a throttle valve by an engine revolution number control means based on a difference between a detected engine revolution number and a target engine revolution number, and the air-fuel ratio control means applies values of at least the engine revolution number and the intake air flow rate to a fuel injection time formula which is derived from a plurality of sets of relational data groups including experimentally-obtained intake air flow rates, experimentally-obtained fuel injection times, experimentally-obtained engine revolution numbers, and experimentally-obtained air-fuel ratios to thereby calculate the fuel injection time for realizing a target air fuel ratio.