Engine modification through reducing nozzle hole diameter (NHD) (i.e., from the base value of 0.28 to the modified value of 0.20 mm) has been shown as an effective strategy in improving engine performance, combustion, and emission parameters. However, it has also led to substantial increases in NOx emission as a major shortcoming. In light of that, the present study was aimed at overcoming this challenge through the application of a partially-cooled exhaust gas recirculation (EGR) system. More specifically, Mahua oil biodiesel-diesel blend (B20) and neat diesel were tested on a modified single cylinder diesel engine under five different engine loads (i.e., 2.46, 4.92, 7.38, 9.84, and 12.3 kg) and in the presence of varying EGR rates (i.e., 10, 20, and 30%). The results obtained revealed that the performance, combustion, and emission characteristics of the modified engine (3-hole nozzle with an orifice diameter of 0.20 mm) were improved for both neat diesel and B20 except in the case of NOx, in comparison with those of the conventional diesel engine (3-hole nozzle with an orifice diameter of 0.28 mm). The considerable increases in NOx emissions caused by the smaller orifice NHD could be successfully compensated for through the implementation of the partially-cooled EGR. Overall and based on the findings of the present study, the proposed engine modification in the presence of partially-cooled EGR rate of 10% could be recommended as efficient combustion conditions for 20% blend of Mahua oil biodiesel and diesel. However, further increments in the EGR rate and in particular at higher loads, adversely affected the performance and emission characteristics of the modified engine due to the recirculation of high amounts of unburnt soot, CO2, H2O, as well as of O2 deficiency. Biofuel; Research; Journal; Biodiesel; Bioethanol; Biogas; Application

The edible and non-edible are the most important feedstocks is to produce biodiesel. Expressions regarding “first generation” and “second generation” of biodiesel are in popular usage. Among both the generations, the second generation is having a very good scope in the future. In this present article, the crude Mahua raw oil has 21% of free fatty acids (FFA). To minimize the FFA to less than 1%, Mahua methyl ester (MME) was produced with an open container as the reactor by two-step of esterification and transesterification methods. The first step was done by the acid catalyzed process by using 0.35 v/v i.e. 175ml of methanol and 1% v/v i.e. 5ml of concentrated H₂SO₄ mixed together and poured in 500ml of warmed preheated Mahua raw oil. The second step was done by alkaline catalyst process by using 0.25 v/v i.e. 125ml of methanol and 0.7% w/v i.e. 3.5gm KOH as catalyst are added in a product produced from the reaction of acid esterification. After two-step process, the crude biodiesel was washed with distilled water over again and later it was added with anhydrous CaCl₂ (Calcium chloride) and heated gently at 50°C. The biodiesel with anhydrous CaCl₂ was shaken vigorously and later separated from the biodiesel to obtain a clean MME biodiesel. These experimental method processes obtained a yield of 85% MME. The high FFA level for crude raw oil was improved to less than 1%. The obtained biodiesel of fuel chemical composition and properties were tested and compared the requirement of American standard for testing materials (ASTM D-6751).

In this article, the mahua tree’s high importance in the present-day plantations is described and the preparation of mahua methyl ester (MME) from the raw mahua seed oil by the two methods of the transesterification process is described. The tested physical properties were compared with the requirement of ASTM D-6751. The obtained MME and its blends of B20, B40, B60, and B80 were investigated in an unmodified diesel engine. From the results of the performance, it has been observed that brake-specific fuel consumption and brake thermal efficiency are slightly improved (B20 and B40) at part-load conditions and approach diesel at full-load conditions. From combustion analysis, it was seen that ignition delay was shorter for biodiesel and its blends compared with the diesel fuel. The emission characteristics of carbon monoxide, hydrocarbons, and smoke opacity were reduced for all the fuel blends, but at high temperatures they undergo an endothermic reaction and produced various oxides of nitrogen.