The main aim of this book is to analyze the effect of utilization of butanol and ethanol on emissions, exhaust temperature, power and efficiency, taken in definite quantities in spark ignition engine with gasoline. Due to concerning shortage of fossil fuels and there harmful effects on environment and human life has lead the world to think about an effective alternative to these, So we will try to reduce all these emissions from the gasoline engines. It is imminent that the petroleum reserve will be finished soon if some alternative fuels does not at least partly replaces petrol and diesel. It should have satisfactory brake power, thermal efficiency, low polluting emissions and should be long lasting and economical. Government has mandated the use of gasoline-ethanol blends in many countries. The Results obtained by this research will be useful for various Automobiles Industries and researchers working in this field.