This study discusses performance and exhaust emissions from spark-ignition engine fueled with ethanol–methanol–gasoline blends. The test results obtained with the use of low content rates of ethanol– methanol blends (3–10 vol.%) in gasoline were compared to ethanol–gasoline blends, methanol– gasoline blends and pure gasoline test results. Combustion and emission characteristics of ethanol, methanol and gasoline and their blends were evaluated. Results showed that when the vehicle was fueled with ethanol–methanol–gasoline blends, the concentrations of CO and UHC (unburnt hydrocarbons) emissions were significantly decreased, compared to the neat gasoline. Methanol–gasoline blends presented the lowest emissions of CO and UHC among all test fuels. Ethanol–gasoline blends showed a moderate emission level between the neat gasoline and ethanol–methanol– gasoline blends, e.g., ethanol–gasoline blends presented lower CO and UHC emissions than those of the neat gasoline but higher emissions than those of the ethanol– methanol–gasoline blends. In addition, the CO and UHC decreased and CO2 increased when ethanol and/or methanol contents increased in the fuel blends. Furthermore, the effects of blended fuels on engine performance were investigated and results showed that methanol–gasoline blends presents the highest volumetric efficiency and torque; ethanol–gasoline blends provides the highest brake power, while ethanol– methanol–gasoline blends showed a moderate level of volumetric efficiency, torque and brake power between both methanol–gasoline and ethanol–gasoline blends; gasoline, on the other hand, showed the lowest volumetric efficiency, torque and brake power among all test fuels.nox depends on engine condition For diesesel engine we take test on biodiesel ,diesel blend ,and butanol-diesel blend. Biodiesel has reduced carbom monoxide emission but incressed NOx emission .

Keywords : DI Diesel Engine, Spiral Manifold, Helical Manifold, Helical-SpiralCombined Manifold, Computational Fluid Dynamics (CFD).