Method for calculating air flow rate at cylinder port and throttle valve opening angle

摘要

To improve a control characteristic of an air/fuel ratio during not only a normal driving operation, but also a transition driving operation, (1) based upon an air-flow rate measured by an air-flow rate meter, a calculation is made of pressure at an air intake manifold, and also another calculation is made of an air-flow rate at a cylinder port with employment of the calculation result and an engine revolution number. (2) A throttle valve angle is calculated only from the calculated air flow rate and the engine revolution number without utilizing a throttle valve angle sensor.