Combustion Characteristics of Diesohol Fuel in a Modern Diesel Engine

To reduce diesel consumption, alternative fuels such as biodiesel have been studies to use in compression ignition (CI) engines. However, biodiesel is still limited to a maximum concentration of 7 % in Thailand. Therefore, other alternative fuels have been searched to replace diesel use. Due to its oversupply in domestic market, ethanol is one of the promising fuel to apply in the CI engine. To use as the blend called diesohol, ethanol is mixed with diesel which added biodiesel as an additive to prevent phase separation. This study has investigated the use to diesohol in a modern diesel engine. Engine performance, fuel consumption and exhaust emissions including HC, NOX were measured. Also, formaldehyde and acetaldehyde formed during ethanol combustion were evaluated. To clearly understand the effect of ethanol on the engine performance and emissions, combustion characteristics was studies by means of in-cylinder pressure measurement. The percentage of ethanol, mixed in the blend, was varied as 5 and 10 %v/v while the concentration of biodiesel was added as 3, 7 and 10 % v/v. The result shows that engine torque and power were reduced when using diesohol as the fuel. HC and NOX were increased as well as carbonyl emissions were higher than the engine using diesel fuel.