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Butanol, which can be produced from biomass, has been suggested as an alternative to ethanol, due to its higher energy density, lower oxygen content and more favorable hygroscopic and corrosive properties. In the Czech Republic, E85 is widely sold at fuel stations and used in ordinary vehicles, both with and without aftermarket control units. This work investigates the potential of ordinary automobiles to run on butanol, and the associated effects on exhaust emissions under real driving conditions. A Škoda Felicia car with a throttle body injection and a Škoda Fabia car with a multi-point port injection have been run on gasoline and its mixtures with up to 85% volume of ethanol, of n-butanol, and of isobutanol (2-methyl-1-propanol). An auxiliary control unit has been used with higher alcohol content. On each fuel, each car was driven 5-6 times along a local test route.

Bioethanol, produced from renewable sources, is promoted as a fuel in higher concentrations in newer flexible fuel engines, and in lower concentrations in the general fleet. Introduction of a blend of 85% ethanol with gasoline (E85) at a competitive price in the Czech Republic has, however, spontaneously resulted in this fuel being used in “ordinary” engines not adapted for this fuel. This study investigates the operation of a typical gasoline car with fuel injection and three-way catalyst on gasoline, E85, and additionally on a blend of 85% n-butanol with gasoline, as butanol features better material compatibility than ethanol. The car was equipped with a portable, on-board emissions monitoring system and driven along a route comprising city and rural roads, including hills. Multiple runs were made on each fuel to verify test-to-test repeatability.

To reduce exhaust emissions and dependency on petroleum-based fuels, various alcohols have been considered as gasoline substitutes for spark ignition engines. In the existing vehicle fleet, the use of ethanol, the most widely used alcohol, is practically limited to blends in relatively small concentrations with gasoline, due to its hygroscopicity, aggressivity, substantially lower heat content, and high latent heat. Butanol has relatively low toxicity, can be produced from biomass, and has higher energy density, lower latent heat, lower hygroscopicity and lower aggressivity than ethanol. In this study, the effects of blends of 30% and 50% of n-butanol (1-butanol) with gasoline on combustion process, engine control unit adaptation and exhaust emissions before and after a three-way catalyst were examined on a 1.2-liter, three-cylinder, four-valves-per-cylinder, naturally aspirated port-fuel-injected Skoda 1.2 HTP spark ignition engine coupled to an engine dynamometer.

Neat, non-esterified vegetable oils, alternative, locally produced, renewable fuels for diesel engines, have considerably higher viscosity than diesel fuel, even when heated. While mechanical injection pumps with volumetric fuel metering compensate for higher viscosity of the fuel by an increased injection pressure, and possibly longer ignition delay is on some engines compensated by an earlier injection due to higher density and bulk modulus of vegetable oils, newer common-rail type systems do not have such mechanism, and inject vegetable oils and diesel fuel at comparable timing and pressures. The complexity of the newer injection systems also raises the issue of the effects of varying fuel properties. This paper reports on laboratory experiments carried on a four-cylinder, 4.5-liter Cummins ISBe4 engine with a Bosch Common Rail injection system, fitted with an auxiliary heated secondary fueling system, and operated on fuel-grade rapeseed oil heated to 50-60°C.