The objective of this research work is to evaluate the performance, combustion, and exhaust emissions of a variable compression ratio diesel engine utilizing diesel 25% rubber seed biodiesel mixture (B25) blended with 25 ppm and 50 ppm of alumina nanoparticle running with different operating conditions. An ultrasonicator was used to make uniform dispersion of alumina (Al) nanoparticles in the diesel–biodiesel mixture. Biodiesel mixture blended with nanoparticles has physicochemical characteristics that are comparable to ASTM (American Society for Testing and Materials) D6751 limitations. The results revealed that the B25 exhibited a lower cylinder peak pressure and lower HRR (heat release rate) than diesel at maximum power. BTE (brake thermal efficiency) of B25 is 2.2% lower than diesel, whereas BSFC of B25 is increased by 6% in contrast to diesel. Emissions of HC (hydrocarbon), CO (carbon monoxide), and smoke for B25 were diminished, while emissions of NOx (nitrogen oxide) were higher at maximum power. Further, the combustion and performance of diesel engine were improved with the inclusion of alumina nanoparticles to biodiesel blends. In comparison to B25, BTE of B25 with 50% alumina nanoparticles (B25Al50) mixture was enhanced by 4.8%, and the BSFC was diminished by 8.5%, while HC, CO, and smoke were also diminished by 36%, 20%, and 44%, respectively. At peak load, the maximum cylinder pressure and HRR of B25 were improved by 4.2% and 6.7%, respectively, with the presence of 50% alumina nanoparticles in a biodiesel blend (B25Al50).

Increasing cost of petroleum fuels, fast depletion of petroleum resources and excessive automotive engine pollution lead to the researchers to search for an alternate fuel like waste lubricant oil and Waste Transformer Oil (WTO) for Compression Ignition engines. In the present investigation, WTO is blended with diesel fuel in the ratio of 30:70 (WTO30) on volume basis and is used in a diesel engine to evaluate the performance, emission and combustion characteristics. Initially the engine was operated with diesel and WTO30 and then the test was repeated with WTO30 at different compression ratios. The results revealed that the BTE was increased by 1.12% at CR20 and CO, HC and smoke emissions were decreased and the NOx emissions were increased for WTO30 with an increase in CR when compared to that of diesel. The cylinder pressure and heat release were increased for WTO30 at CR20:1 compared to that of WTO30 at maximum load.

This research work investigates the influence of different injection timing (IT) on working characteristics of an engine with 20% Yellow Oleander biodiesel (YOBD20) blend. Experimental tests have been conducted with a YOBD20 blend at different ITs such as 23°BTDC, 25°BTDC, and 21°BTDC were original, advanced, and retarded ITs. From the experimental results, BTE of YOBD20 with advanced IT of 25°bTDC increased by about1.24% higher than YOBD20 at original IT, while the BSFC was diminished by 9% and the NOx emission were increased by 14.2%, while CO, HC, and smoke emissions were decreased by 26.2%, 22%, and 28%, respectively, when contrast with diesel at original IT of 23°BTDC. Further, the NOx emission was diminished by 32% for YOBD20 with retarded IT of 21°BTDC with the penalty of BTE by 0.896% and the other emissions were increased as compared to diesel at original IT. The cylinder pressure, heat release rate (HRR) and rate of pressure rise (ROPR) were increased at advanced IT and for the retarded IT, the performance was slightly inferior due to slow combustion. Further, the NO emission would be reduced with the help of adopting with exhaust gas recirculation (EGR) along with retarding the injection timing. Abbreviation: YOBD: Yellow Oleander Biodiesel; YOBD20: 20% Yellow Oleander Biodiesel +80% Diesel; ppm: Parts per million; CO2: Carbon dioxide; BTDC: Before Top Dead Center; MROPR: Maximum rate of pressure rise; EGT: Exhaust gas temperature; NOx: Oxides of Nitrogen; UBHC: Unburned Hydrocarbon; HRR: Heat release rate; IP: Injection pressure; NOP: Nozzle opening pressure; kWh-kilo Watt hour; EGR: Exhaust gas recirculation; CA: Crank angle

This research investigates the cause of nozzle opening pressure (NOP) on diesel engine overall performance, emission and combustion characteristics using 20%Yellow Oleander biodiesel (YOBD20) blend with different operating conditions. Initially the engine test was conducted using diesel and YOBD20 at standard NOP of 200bar and then the experiment was repeated with YOBD20 at different NOPs of 200bar, 220bar, 240bar and 260bar. The obtained results were compared to diesel and YOBD20 blend at recommended NOP of 200bar. The results showed that BTE, CO, HC and smoke emissions were decreased, while the NOx emissions were increased with an increase in NOPs. The combustion parameters like cylinder pressure, heat release rate and the rate of pressure rise were enhanced with an increase in NOPs at full load. It is found the YOBD20 with 240bar NOP gave the better performance and drastic reduction in all emissions except NOx emissions.

Conservation of energy is an important task for the present world which can be achieved by minimizing the usage of conventional fuel and by utilizing non-conventional sources. Solar energy is abundant source of renewable energy which can be used for the thermal and electrical applications. In solar thermal applications there is a need of energy storage for later use. This thermal energy Storage can be done by sensible/Latent heat storage methods. In the present work latent heat storage method using phase change materials is considered. Experiments have been conducted in a cylindrical shell type heat exchanger and spherical ball type storage chamber for the solar thermal energy storage. Paraffin wax, Palmitic acid and eutectic mixture of paraffin wax and Palmitic acid have used as phase change materials (PCMs) to store the solar energy and the results were compared for both the type of storage devices.