V. K. Rao

Improving the Fuel Economy of Stoichiometrically Fuelled S.I. Engines by Means of EGR and Enhanced Ignition - A Comparison of Gasoline, Methanol and Natural Gas

This paper describes an experimental study in which the potential for fuel economy improvements with EGR was investigated using an automotive V6 engine. Steady state engine dynamometer tests were run at 2,000 rpm and 200 kPa Brake Mean Effective Pressure (BMEP). The engine was fueled with gasoline, methanol or natural gas. Plasma jet ignition was evaluated as a means of improving EGR tolerance. EGR tolerance with methanol was found to be better than with gasoline, while natural gas showed the poorest EGR tolerance. Plasma jet ignition extended EGR limits for all three fuels. Fuel economy benefits were realized with natural gas and gasoline at low EGR rates and without EGR but plasma jet ignition provided no improvements with methanol until over 10% EGR was used. Plasma jet ignition made stable operation possible with methanol at 40% EGR, where fuel economy improvements were ultimately limited by the slow burning associated with the high EGR rate. Both slow burning and high cyclic variation affected gasoline at high EGR rates, while stability limits to spark advance with natural gas caused fuel economy to degrade at relatively low EGR rates.

Review of the Cold Starting Performance of Methanol and High Methanol Blends in Spark Ignition Engines: High Methanol Blends

This paper summarizes the results of a survey and analysis of cold starting data for spark ignition engines utilizing high methanol blends. All available published information, as well as additional data supplied by contributing agencies was considered. The report includes graphical comparisons of test results and a detailed discussion of the various factors which influence cold starting. Recommendations are made for further work needed to improve cold starting.

Volatility and flammability of methanol/gasoline blends

Computational procedures are described for combining a simple multicomponent fuel volatility model with flammability data to facilitate the analyses of a wide variety of practical situations involving methanol/gasoline blends. These include fire hazards, fuel droplet or film evaporation, ignition, combustion and engine cold starting

A Vapour Pressure Model for Methanol/Gasoline M85 Blends

This paper presents an analytical model for M85 volatility behaviour. It uses a recently developed technique for gasoline volatility in conjunction with a modified form of Raoults Law corrected for non-ideality. Vapour pressure, methanol/gasoline distribution in the vapour phase and enthalpy of evaporation are all calculated using explicit equations. Constants needed for the equations are given for one M85 blend and a simple method of deriving them for any other gasoline/methanol mixture using only measured RVP is outlined. In addition to describing the new predictive technique, the paper gives the results of an experimental program in which vapour phase composition and vapour pressure behaviour were measured at various temperatures and vapour/liquid ratios.

COLD STARTING PERFORMANCE OF GASOLINE/METHANOL M10 BLENDS IN A SPARK IGNITION ENGINE

Engine cold starting tests have been conducted in a laboratory cold chamber to compare the performance of three 10% methanol/90% gasoline blends with that of Indolene. The blends had different Reid Vapour Pressures and tests were conducted over a wide range of fuel/air ratios at temperatures as low as -45 deg C. It was found that all M10 blends tested had poorer starting performance than Indolene at cold temperatures, including those of nominally higher volatility. Cold starting did not correlate to Reid Vapour Pressure even when comparing two oxygenated fuels. Graphs are presented showing minimum cold starting temperature as a function of fuel-air equivalence ratio.