Abstract: A fuel-injected internal combustion engine and a method for calculating mass air flow in the fuel-injected internal combustion engine having an electronic control of the air fuel ratio employing a throttle for air flow control, including a device for sensing air pressure downstream of the throttle. The method for calculating mass air flow includes measuring the speed of the fuel-injected internal combustion engine, measuring the opening of the throttle, and, omputing total intake mass air flow using algorithms, which includes the product of two terms, a first term substantially representing a function of the downstream air pressure and a second term being substantially a function of the speed of said fuel-injected combustion engine and the throttle opening.

Abstract: A method of mass-flow determination for an internal combustion engine which comprises developing two terms, one being a function of the air pressure downstream of the throttle and the other being a function of engine speed and throttle opening as determined by appropriate transducers. Specifically the invention recognises that the term which is a function of air pressure is a substantially straight line and, for calibration purposes can be accepted so calibration is effectively done by modifying the other term to provide optimum performance under various conditions. The mass flow determination is a product of the two terms. The invention also provides an internal combustion engine being controlled by the use of the method.