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A range of gasoline/alcohol blends containing methanol, ethanol, iso-propanol and n-propanol, up to 5% oxygen content by mass, was tested in a multi-valve production engine to quantify the raw exhaust emissions, performance and burn-rate. A heat-release model was developed to facilitate the quantification of burn-rate. The engine was operated with various control strategies to enable the results to represent the response of different engine types. With standard open-loop engine calibration the alcohols reduced the equivalence ratio which resulted in increased combustion duration and reduced regulated emissions, while there was no difference between the effects of the different alcohols.

The Motor Octane Number (MON) ranks fuels by their chemical resistance to knock. Evaporative cooling coupled with fuel chemistry determine Research Octane Number (RON) antiknock ratings. It is shown in this study that fuel Octane sensitivity (numerically RON minus MON) is linked to an important difference between the two test methods; the RON test allows each fuel's evaporative cooling characteristics to affect gas temperature, while the MON test generally eliminates this effect by pre-evaporation. In order to establish RON test charge temperatures, a computer model of fuel evaporation was adapted to Octane Engine conditions, and simulations were compared with real Octane Test Engine measurements including droplet and gas temperatures. A novel gas temperature probe yielded data that corresponded well with model predictions. Tests spanned single component fuels and blends of isomers, n-paraffins, aromatics and alcohols.