Journal of Energy Bioscience 2025, Vol.16, No.5, 216-226 http://bioscipublisher.com/index.php/jeb 218 fatty acids is relatively low, approximately 7% (Nath et al., 2016; Nje et al., 2023). Through breeding and genetic engineering, researchers have developed different types of rapeseed oil, such as high oleic acid type (oleic acid up to 86%) and high erucic acid type (erucic acid up to 78%), which can meet the needs of industrial use and biodiesel production. 3.2 Key quality parameters: viscosity, density, iodine value, saponification value Rapeseed oil and biodiesel produced from it can generally meet international standards (EN14214, ASTM D-6751) (Rashid and Anwar, 2008; Essamlali et al., 2017; Rezki et al., 2020). In terms of parameters, the kinematic viscosity of rapeseed oil biodiesel is usually between 4.0 and 5.0 mm²/s (at 40 ℃), meeting the standards (Shapovalov et al., 2025). Its density is 0.88~0.90 g/cm³(at 15 ℃), which is similar to mineral diesel. The iodine value reflects the unsaturation of oil products. The iodine value of rapeseed oil biodiesel is generally between 110 and 120 g I2/100 g, which is higher than that of palm oil and soybean oil (Rashid and Anwar, 2008; Nath et al., 2016). The saponification value is usually between 190 and 195 mg KOH/g, which indicates that it is very suitable for ester exchange reactions. 3.3 Oxidative stability and implications for storage and engine performance Due to the high proportion of unsaturated fatty acids, the oxidation stability of rapeseed oil biodiesel is relatively poor. It is prone to oxidation during storage, which will increase the acid value, increase the viscosity and form precipitates (Rashid and Anwar, 2008; Khan et al., 2023). If the stability is insufficient, it may affect the long-term use of the engine. However, this problem can be improved by adding antioxidants or increasing the proportion of oleic acid. 4 Fuel Properties of Rapeseed Oil Biodiesel 4.1 Cetane number, calorific value, pour point, cloud point, flash point The cetane number of rapeseed oil biodiesel (RME) is generally between 51 and 54, which is slightly higher than that of diesel, which is beneficial for engine ignition and combustion (Karaosmanoglu et al., 1997; Rashid and Anwar, 2008). Its high calorific value is slightly lower than that of mineral diesel, approximately 37~40 MJ/kg, but it can still meet the energy requirements of the engine (Ong'era et al., 2023). However, its freezing point and cloud point are relatively high, and its fluidity at low temperatures is worse than that of diesel. Additives need to be added or it needs to be mixed with diesel to improve (Rashid and Anwar, 2008; Stiemicek et al., 2010; Brock et al., 2018). Its flash point is usually greater than 120°C, higher than that of diesel, so the fuel is safer. 4.2 Emission characteristics compared with diesel and other biodiesels When rapeseed oil biodiesel is used in the engine, CO and particulate matter (PM) emissions can be reduced by up to 60%, but NOx and CO2 emissions are slightly higher than those of diesel (Buyukkaya, 2010; Aldhaidhawi et al., 2017). Compared with biodiesel such as soybean oil and palm oil, its emission performance is roughly similar. However, due to the high proportion of unsaturated fatty acids, NOx emissions are slightly higher. If hydrogen or nano-additives are added during combustion, the emissions of CO and HC can be further reduced, but NOx still needs to be controlled through post-treatment (Brock et al., 2018; Thiagarajan et al., 2024; Gulcan et al., 2025). 4.3 Engine performance outcomes from literature studies Many studies have shown that the power of rapeseed oil, biodiesel and their blended fuels in engines is similar to that of diesel. The fuel consumption rate is slightly higher than that of diesel, approximately 8%~11% more, and the thermal efficiency is also slightly lower (Buyukkaya, 2010; Latypov et al., 2021; Zapevalov et al., 2021). The ignition delay time is shortened, the combustion is more stable, but the exhaust temperature will increase slightly. The study also found that the addition of nanoparticles (such as TiO2, CeO2) can improve energy utilization efficiency and heat release efficiency, and also reduce costs, but the environmental impact still needs to be further evaluated (Gulcan et al., 2025).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==