Electronic control system for internal combustion engine

An electronic control system for internal combustion engine, in which parameters necessary for the engine control are found out by use of auxiliary quantities to thereby control the operating characteristic quantities of the internal combustion engine, said electronic control system comprising:

• memory means for storing in advance, in the form of a two-dimensional map, at least one parameter selected from the group comprising a charging efficiency per se and related values of the charging efficiency corresponding to a degree of opening of the throttle valve and a number of engine revolution under a reference atmospheric condition;
• and computing means for computing atmospheric pressure related values which include therein at least the atmospheric pressure value and are dependent on the atmospheric pressure, in accordance with a predetermined computation equation which takes a ratio of a parameter selected from the group comprising a charging efficiency per se and related values of the charging efficiency to be found out by selective use of signals of the intake air flow rate and a number of revolution of the internal combustion engine.