| 摘要 |
PURPOSE:To prevent the air-fuel ratio of the engine from being overcorrected or being insufficiently corrected by a method wherein the allowable range of the air-fuel ratio is switched in proportion to the altitude of a place on which a vehicle travels so that the air-fuel ratio may follow flexibly the variation of the density of air taking place when the altitude of the place changes suddenly. CONSTITUTION:Q block numbers detected on the base of the quantity of sucked air measured by an air flow meter 12 are stored in RAM104 and the average value of the correcting amounts of 1st and 2nd Q blocks and the average value of the correcting amounts of 15th and 16th Q blocks are stored in the RAM104 as the minimum reference value and the maximum reference value, respectively. Next, the difference between the two reference values is calculated and values to be interpolated between the two reference values are calculated. That is, provisional correcting values of 3rd-14th Q blocks are calculated, the calculated values are stored in the RAM104 and when the Q block of the present air is at a low ground, a guard amount of about 3-5% is added to each of the correcting values to thereby obtain a learned critical value while when it is at a high ground, a guard amount of about 8-10% is added to each of the correcting values to thereby obtain another learned critical value. Further, in case when the above mentioned critical values are the correcting values actually experienced, the correcting values are stored in a non-volatile RAM106 and when smaller, the learned critical values are stored in the RAM106 so that the stored values are used to control the air-fuel ratio in performing an open loop control. |
