Method of controlling air/fuel ratio in internal-combustion engine

Abstract

Abstract PURPOSE:To reduce shock upon switching from a stoichiometric air/fuel ratio to a lean air/fuel ratio and vice versa according to temperatures and load conditions of an internal-combustion engine, by gradually varying the amount of fuel to be injected. CONSTITUTION:An operation control circuit for controlling a valve opening time of a fuel injection valve according to various operational parameters serves to determine at steps 30 to 32 whether or not an air/fuel ratio has been switched from a stoichiometric air/fuel ratio to a lean air/fuel ratio and vice versa. When the operation control circuit determines that the air/fuel ratio has been switched, it computes at a step 33 DELTATp given by equally dividing into n the difference between the present injection amount TPN and the previous injection amount TPO and thereby to restrict at steps 35 and 36 the difference in the injection amount in such a manner that the difference is kept not more than DELTATP.

Inventors

• 👤 Shigeru Sasaki
• 👤 茂 佐々木

Bibliographic Details