This study is intended to examine the ignition characteristics of a cashew nut shell biodiesel (C100) along with ethyne (acetylene) as a dual fuel in a diesel engine. Cashew nut shell oil is employed in this study owing to non-toxic nature, free from sulphur, biodegradable, and free of aromatics. Ethyne gas was introduced at different flow rate of 2, 4, 6 litres per minute (lpm). Experimental results revealed that duel fuelling ethyne gas to base fuel (C100) at 6 lpm reduce 18.1% CO, 9.7% HC, 6.87% Smoke with 11.1% increase in NO emissions. Higher thermal efficiency was observed for ethyne-biodiesel mixture than neat biodiesel in all flow rates. Furthermore, the heat release and peak pressure were enhanced by duel fuelling ethyne gas to base fuel (C100).