A fuel composition for spark ignition engine.

The invention relates to a fuel composition for spark ignition engine. The composition according to the invention comprises: (1) a gasoline spark ignition engine and (2) an oxygen-containing organic compound which contains both in its molecule (a) a triple bond or a double bond and (b) an oxygen atom. The fuel composition of the invention allows in particular to optimize the ignition timing and to improve the flame propagation speed in a wide range of fuel / air ratios, the engine output independently operating conditions and the ignition capacity without metal components with a lean or rich mixture and to reduce fluctuations of cycles due to variations of the mixture, thereby lowering the fluctuations of the mean effective pressure indicated, the maximum cylinder pressure, etc. independently of variations in the mixing ratio.