OPERATION OF THE SPARK IGNITION ENGINE WITP NATURAL GAS

Abstract

Natural gas is considered nowadays to be one of the most vital sources of energy. It is extracted from different areas. Natural gas consists of different gases which differ in percentages depending on the extraction place, and also differ within the same source from time to another. This obviously results in variation in both the physical and chemical propertiesand hence particular considerations should be taken when using natural gas as a fuel in internal combustion engines. The aim of this work is to study the effect of using the associated natural gas as a fuel ,on a natural gas engine specified and adjusted with another natural gas fuel by the engine manufacturer. The experimental work was performed on a stationary gas engine generator set ,on an off shore platform for crude oil collection in the Gulf of suez. It has a brake power of 450 kW at 1200 rpm and compression ratio of 7:1. Appropriate adjustments of the engine fuel system, and the ignition timing were implemented to accommodate for the difference in gas characteristics. The main differences between the two gases are the calorific value and the Octane number. The engine was loaded by different loads (I/4, 1/2, 3/4, and full load). The measurements include the values of the brake power and the percentages of the dry volume ) fractions of CO and 02 in the exhaust during each run. Hence, the air/fuel ratio was calculated. Also, the differential pressure between the gas and air at the mixer entry was monitored.