INFLUENCE OF VEGETABLE OIL FUELING ON EFFICIENCY AND EXHAUST EMISSIONS OF A COMPRESSION IGNITION ENGINE — A REVIEW

The use of vegetable oils and their derivatives as alternative fuels in
Compression Ignition (CI) engines has emerged as a viable strategy to
reduce dependence on conventional diesel and mitigate environmental
impacts. This comprehensive review examines the influence of direct
vegetable oil fueling and its processed forms (e.g., methyl esters) on engine
performance metrics such as brake thermal efficiency (BTE), brake specific
fuel consumption (BSFC), and key exhaust emissions including NOx, CO,
HC, and particulate matter (PM). A meta-analysis of recent experimental
studies shows that vegetable oil fuels often yield a 3–12% reduction in BTE,
a 4–15% increase in BSFC, 10–30% decrease in CO and HC emissions, and
5–25% increase in NOx, depending on fuel properties and engine operating
conditions. The review contextualizes these findings with respect to
combustion characteristics, fuel physicochemical properties, and engine
modifications. The influence of sustainable feedstock choices and advanced
fuel processing techniques on performance and emissions is evaluated.