Investigation of 2-butoxyethanol as biodiesel additive on fuel property and combustion characteristics of two neat biodiesels

Neat biodiesels are not preferred for use in the compression ignition (CI) engines due to their high viscosities and related operational difficulties. This study investigated the fuel properties and combustion characteristics when 2-butoxyethanol additive was mixed separately with waste cooking oil biodiesel (W100) and rapeseed oil biodiesel (R100). Compared to neat biodiesels, the viscosities (at 40 ⁰C) of the W100 and R100 were reduced by 12.5% and 9.8% respectively, when they were blended separately with 15% 2-butoxyethanol. Four different samples such as W100, mixture of 85% W100 and 15% 2-Butoxyethanol (W85), R100, mixture of 85 % R100 and 15% 2-Butoxyethanol (R85) were tested in a multi-cylinder CI engine. The thermal efficiency of the W85 fuel was higher than fossil diesel by approximately 3.7%. Total combustion duration of the biodiesel-additive blends were shorter than neat biodiesels and fossil diesel. Biodiesel-additive blends provided approximately 6% higher in-cylinder peak pressures. At full load, W85 fuel gave up to 5.4% reduced NOx emissions than neat biodiesel. The CO, HC and smoke emissions were decreased by up to 36%, 100% and 79% respectively. The study concluded that 2-butoxyethanol could effectively be used as biodiesel additive to improve fuel property; and to achieve better combustion and reduced pollution.