METHOD AND DEVICE FOR CONTROLLING SUPPLY OF VAPOR-LIQUID FUEL MIXTURE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To optimally control supply of the air-fuel mixture to an internal combustion engine independently of a change of the fuel condition with consumption of the vapor-liquid fuel mixture. SOLUTION: H/C ratio Rhc of the air-fuel mixture in the gaseous condition is computed on the basis of a detected concentration B of butane (S150). A theoretical air-fuel ratio Rt is computed on the basis of the H/C ratio Rhc (S200). A correction coefficient Ka of a fuel injection period is computed on the basis of the concentration B of butane and the theoretical air-fuel ratio Rt (S250). A basic fuel injection period Tb as the optimal fuel injection period when the natural gas is contained at 100 % is computed (S300). A first target fuel injection period T1 is computed on the basis of the basic fuel injection period Tb and the correction coefficient Ka (S400). A second target fuel injection period T2 for reducing a deviation between the real air-fuel ratio Ra and the theoretical air-fuel ratio Rt is computed (S450). A fuel injection period in relation to an air intake pipe 32 by a fuel injection device 28 is controlled on the basis of the final target fuel injection period Tt as the sum of the first and the second target fuel injection periods (S500, S550). COPYRIGHT: (C)2004,JPO