Performance of Naturally Aspirating IC Engines Operating at High Altitude

Abstract

The loss of power and the increase of fuel consumption of naturally aspirating IC engines operating with low atmospheric pressure at high altitude as well as changes in the mixture quality with non adapting mixture formation systems are principally known. Other effects like the additional advance of ignition timing in petrol engines or the injection timing of Diesel engines as well as changes of the exhaust gas quality are usually not considered and no measures are taken in many developing countries - even when having extended highlands - for improving the economic and environmental consequences of such unfavourable engine operation.

After reconsidering the important influences and their theoretical background in high altitude engine operation some results out of road and laboratory tests with conventional petrol engines obtained in Ethiopia are shown as well as proposals for simple adaptation of engine systems.