THE EFFECTS OF AIR-FUEL RATIO ON AUTOMOBILES VIBRATIONS

This paper studies the effect of the change in air-fuel ratio on the engine and automobiles vibrations. Principle of vibration analysis is used to determine the system behavior. Air-fuel ratio is studied, as an input parameter, for stoichiometric, rich and lean fuels. Such changes in air-fuel ratios makes the engine and so the automobile to vibrate significantly. A benzene automobile with1800 CC - 4 cylinders engine is tested and an accurate vibrometer is used to sense such vibrations. It is found that there is an effect for the air-fuel mixture on the vibration of the engine and on the car as a whole. Rich mixtures have the highest frequencies at most record time. It is theoretically expected due to the high energy released by the combustion in which all of the oxygen is consumed.