AIR-FUEL RATIO CONTROL DEVICE FOR ALCOHOL-GASOLINE MIXED FUEL

摘要

PURPOSE:To precisely control an air-fuel ratio, by detecting the concentration of alcohol in gasoline from outputs of hygrometers provided in a suction passage and an exhaust passage, and adjusting an amount of fuel to be supplied. CONSTITUTION:In an engine using an alcohol-gasoline mixed fuel, hygrometers 23a and 23b are provided in an exhaust pipe 21 and a suction duct 14, respectively. Output signals from the hygrometers together with signals from the other sensors are inputted into a control device 30 to detect the concentration of alcohol in gasoline from the output signals of both the hygrometers and thereby adjust a fuel quantity to be injected from a fuel injection valve 11. Accordingly, an air-fuel ratio may be precisely controlled irrespective of a moisture quantity in the atmosphere.