Rubber seed (Hevea brasiliensis) oil biodiesel emission profiles and engine performance characteristics using a TD202 diesel test engine

In this study, biodiesel produced from seeds obtained from a Nigerian bioengineered rubber tree (Hevea brasiliensis, NIG800 series) was investigated for engine performance analysis and emission study. All tests were conducted for diesel, biodiesel, and blends over the entire speed range (1500-3500 rpm, at increments of 500 rpm) under full load operating conditions. The results showed that the brake specific fuel consumption is higher for biodiesel and blends compared to diesel due to the lower heating value of the biodiesel, but B20 and diesel results were the same (0.20 kg/kWh) at 2750 rpm. Exhaust gas temperature is significantly higher for biodiesel because the higher oxygen content (10-12%) and higher cetane number assisted complete combustion. Engine power, brake thermal efficiency, and engine torque were higher with diesel fuel compared to biodiesel and blends because of the higher energy content of diesel fuel. There is a significant reduction in carbon monoxide, unburned total hydrocarbons, and smoke opacity with biodiesel, but nitric oxide and carbon dioxide increased slightly. The B20 blend at 2500 rpm shows the best performance, and biodiesel sourced from rubber seeds is environmentally friendly and can be used in modern diesel engines without technical modifications.