METHOD AND APPARATUS FOR MEASURING AMOUNT OF EVAPORATED FUEL, METHOD AND APPARATUS FOR CONTROLLING AIR-FUEL RATIO, AND CANISTER

摘要

PROBLEM TO BE SOLVED: To measure a supply amount of an evaporated fuel supplied into an intake pipe from a canister with high accuracy without using an ultrasonic sensor, and to properly control an air-fuel ratio of an air-fuel mixture supplied to an internal combustion engine on the basis of a result of the measurement of the supply amount of the evaporated fuel. SOLUTION: A basic fuel injection time T0 and an air-fuel ratio correction coefficient KF are calculated (S10-S20) on the basis of signals from various sensors, and a flow rate Y of air flowing into a canister and a flow rate X of an air-fuel mixture flowing into an intake pipe are measured (S140, S150) when a purge valve is opened. Then a correction time Tp as a valve opening time of an injector corresponding to the supply amount of the evaporated fuel into the intake pipe is calculated (S160), on the basis of the difference between the flow rate X of the air-fuel mixture and the flow rate Y of the air. The basic fuel injection time T0 is corrected on the basis of the air-fuel ratio correction coefficient KF and the correction time Tp to calculate (S180) an optimum valve opening time T of the injector.