Air-fuel ratio controller for internal combustion engine

Abstract

Abstract PURPOSE:To keep off the worsening of drivability by calculating a decrement correction value for decrement of fuel on the basis of a difference between air-fuel ratio correction factors when the air-fuel ratio correction factor has become less than the specified value and at time just before a purge start. CONSTITUTION:A difference between an air-fuel ratio correction factor at a time when the air-fuel ratio correction factor has become less than the preset value by starting a purge of fuel to an engine inlet system and an air-fuel correction factor at time just before the purge start is found by a substruction means 102. On the basis of a difference between these air-fuel ratio correction factors, a decrement correction value for decrement of fuel is calculated by a decrement correction value calculating means 103. Next, a fundamental fuel injection quantity is compensated for decrement on the basis of this decrement correction value by an air-fuel ratio compensating means 104, while the air-fuel ratio correction factor should be forcibly set to the value just before the purge start. Then, the decrement correction value after being corrected is made smaller by degrees. With this constitution, even if an accelerator pedal is operated during the purge, an air-fuel ratio is in no case rarefied too much and, what is more, drivability will not be worsened at all.

Inventors

• 👤 Koji Uranishi
• 👤 康次 浦西
• 👤 Takaaki Ito
• 👤 隆晟 伊藤

Bibliographic Details