This paper focuses on the combustion performance of various blends of biodiesel fuels and diesel fuel from lean to rich mixtures. The biodiesel blend fuel combustion experiments were carried out using a liquid fuel burner and biodiesel fuel made from various plant oil feedstocks, including jatropha, palm and coconut oils. The results show that jatropha oil methyl ester blend 25 (JOME B25) and coconut oil methyl ester blend 25 (COME B25) blended at 25% by volume in diesel fuel produced lower carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions due to more complete combustion. Overall, JOME B25 had the highest CO emission reduction, at about 42.25%, followed by COME B25 at 26.44% emission reduction relative to pure diesel fuel. By contrast, the palm oil methyl ester blend 25 (POME B25) showed a 48.44% increase in these emissions. The results showed that the nitrogen oxides (NO_x) emissions were slightly higher for all biodiesel blend fuels compared with pure diesel fuel combustion. In case of sulphur dioxide (SO₂) and UHC emissions, all biodiesel blends fuels have significantly reduced emissions. In the case of SO₂ emission, the POME B25, JOME B25 and COME B25 emissions were reduced 14.62%, 14.45% and 21.39%, respectively, relative to SO₂ emission from combusting pure diesel fuel. UHC emissions of POME B25, JOME B25 and COME B25 showed 51%, 71% and 70% reductions, respectively, compared to diesel fuel. The conclusion from the results is that all the biodiesel blend fuels are suitable and can be recommended for use in liquid fuel burners in order to get better and ‘greener’ environmental outcomes.

A study on the application of oxygenated turpentine oil as a bio-additive in diesel fuel was conducted. The purpose of this research was to investigate the effect of oxygenated turpentine oil additive in diesel fuel on the performance and emission characteristics in diesel engines. Oxygenated turpentine oil is obtained from the oxidation process of turpentine oil. In this experimental study, the influences of oxygenated turpentine oil-diesel blended fuel OT0.2 (0.2% vol oxygenated turpentine oil and 99.8% vol diesel) were compared with pure diesel on engine performance, and emission characteristics were examined in a one-cylinder four-stroke CI engine. The test was performed at two engine loads (25% and 50%) and seven engine speeds (from 1200–2400 rpm with intervals of 200 rpm). The physiochemical characteristics of test fuels were acquired. The engine indicated power, indicated torque, fuel flow rate, and emissions (carbon dioxide, CO₂; carbon monoxide, CO; and nitrogen oxide, NO_X) were examined. The results revealed that the engine power shows slight increments of 0.7–1.1%, whereas the engine torque slightly decreased with oxygenated turpentine usage compared to pure diesel in most conditions. Furthermore, a reduction in NO_X emission decreased by about 0.3–66% with the addition of oxygenated turpentine in diesel compared to diesel. However, usage of OT0.2 decreased fuel flow rate in most speeds at low load but gave a similar value to diesel at 50% load. CO emissions slightly increased with an average of 1.2% compared to diesel while CO₂ emissions increased up to 37.5% than diesel. The high-water content, low cetane number, and low heating value of oxygenated turpentine oil were the reasons for the inverse effect found in the engine performances.