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From the energy security and CO2 reduction point of view, much attention has been paid to the usage of bio-fuel. Recently, highly concentrated ethanol is used in some areas (“E85”; 85% ethanol and 15% gasoline in North America and Sweden, and “ethanol”; 93% ethanol and 7% water in Brazil). In these regions, Flexible Fuel Vehicles FFVs are being introduced that are capable of using fuels with a wide range of ethanol concentrations. Advantages of highly concentrated ethanol in internal combustion engine applications are higher thermal efficiency obtained due to higher octane number, and a reduction of nitrogen oxides due to lower combustion temperatures On the other hand, the latent heat of vaporization for ethanol is greater than gasoline, causing poor cold startability and high NMOG emissions. This paper examines the effect of highly concentrated ethanol on exhaust emissions at cold start in a SI- engine.

During the development of conventional PFI engines, WOT (Wide Open Throttle) performance tends to be sacrificed for exhaust emission reduction in order to meet the latest emissions regulations. To satisfy both power and emissions, a new V-6 engine employing stoichiometric gasoline direct injection, the 3GR-FSE, with variable intake and exhaust valve timing systems, was developed and meets the ULEV exhaust emission standard without sacrificing WOT performance. It is generally understood that THC emissions are reduced during warm-up through quick catalyst light-off by retarding ignition timing. However, the effect of this is limited by engine torque fluctuations. Under this warm-up condition, stratified charge combustion is known to significantly improve the engine torque fluctuation and enable more retard ignition timing.