Although it has long been recognized that tight air to fuel ratio control under all engine operating conditions should improve engine fuel economy and simplify emissions control, economical, precision and packageable devices for measuring these parameters have not been available for engine control application. Fuel and air input systems, consequently, have continued to rely on other alternate methods of controlling the air to fuel mix.In recent years, advancements in both sensor and electronic technology have begun to make available to the engine control systems engineer compact,high accuracy/reliability devices that offer possibilities of even tighter fundamental controls. At Ford Motor Company, one such car engineering concept that has been under development for several years is a precision engine air input measuring meter. Using both temperature and pressure sensors to normalize incoming air calculations, this vortex shedding principle meter constantly reports at a high electronic data rate the mass air inflow to the engine. Key elements of this composite device are economical, wide range, high accuracy sensors.