Air-fuel ratio controller for electronically controlled fuel injection engine

Abstract

Abstract PURPOSE:To improve the fuel consumption by feeding the secondary air into an intake passage and spreading the control range for airfuel-ratio, when the air-fuel-ratio is made overrich by the evaporated gas purge and the min. fuel injection quantity state continues and the control-disabled state is generated. CONSTITUTION:An internal combustion engine equipped with an evaporated fuel adsorbing device (canister) 20 having a purging passage is equipped with a calculating means 1 which corrects the fundamental fuel injection quantity according to the air-fuel ratio feedback correction coefficient FAF and calculates the final fuel injection quantity TAU. The FAF is calculated on the basis of the output of an O2 sensor 14 by a calculating means 2, and the lower limit value as lower limit guard is set. When it is detected by a purge detecting means 3 that a large quantity of purged gas is discharged into an intake passage 11, the lower limit guard is released by a guard control means 4. In this case, a secondary air feeding means 5 for feeding the secondary air into the intake passage 11 when the fuel injection quantity becomes the min of a fuel injection valve is provided.

Inventors

• 👤 Takaaki Ito
• 👤 Koji Uranishi

Bibliographic Details