AIR-FUEL RATIO CONTROL DEVICE FOR ENGINE

摘要

PROBLEM TO BE SOLVED: To control an air-fuel ratio to be proper without wastefully injecting an excessive amount of fuel after releasing an exhaust brake without being affected by rise of auction air pressure (and suction air temperature) by working of the exhaust brake on an air-fuel ratio control device of an engine surnished with a means to assume intake fluid quantity A of the engine in accordance with engine speed and suction air pressure on the throttle valve downstream side and a means to find basic supply quantity of fuel in accordance with the intake fluid quantity A. SOLUTION: There are provided a means to judge whether starting of fuel injection is required or not when an exhaust brake is released (step 1-step 5), a means to find intake fluid quantity B in accordance with engine speed Ne and throttle opening when the opening of fuel injection is required in accordance with this judgement (step 6-step 8) and a means to select the intake fluid quantity B as the intake fluid quantity A required to find the basic fuel injection quantity under a condition of establishment of intake fluid quantity B<=intake fluid quantity A with a limit that specified time passes after the time of releasing the exhaust brake by comparing the intake fluid quantity A and the intake fluid quantity B with each other (step 9 and the step 3).