Method and apparatus for detecting air in fuel

摘要

This disclosure relates to detection of air in the fuel supply system of an internal combustion engine of the character wherein the fuel rate supplied to the engine is controlled by regulating the feed pressure to a set of fuel injectors. A pressure sensor is connected in the fuel supply system and an engine speed sensor is connected to the engine. The engine is started, brought to a stable intermediate no-load speed, the throttle is snapped to a wide open position, and the rate of change of fuel pressure with time is sensed during the initial pressure rise from no load pressure to full load pressure. This measured rate is compared with a reference rate obtained from an engine where no air is present in the fuel system, and the pressure of air is indicated by a comparison of the measured and reference rates.