الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
Natural gas was found to be a good vehicle fuel in comparison with other
alternative fuels such as gasoline for its availability and reduced emissions.
The previous researches proved that the reduction of volumetric efficiency
is about 9.6%, the reduction in average flame speed reaches about 30% at
3000 rpm, and the reduction of power for pure eNG is about 18%, at full
throttle opening when using eNG in a spark ignition engine originally
designed for gasoline.
A practical research was made on a spark ignition engine model (1974) Fiat
128 to study the factors affecting the performance of the engine, and it is
concentrated on three main points:
- Increasing the spark advance.
- Increasing spark power.
- Mixing the NG with air in a new mixing point (below the throttle).
The spark was advanced 10 degrees before the optimum timing for the
gasoline fuel to improve the engine performance in case of using eNG as a
fuel. The increased spark energy provided by the high energy electronic
ignition system in parallel with the normal ignition system improved the ignition of the extremly lean mixtures when increasing the spark duration.