The aim of the present investigation is to examine the characteristics of diesel engine for varying concentrations of diethyl ether (DEE) as an oxygenated additive in repurpose used cooking oil (RUCO) biodiesel and diesel blends. In the beginning, several pilot experimentations are carried out on diesel and B20 blend. Afterward, 0.8%, 1.6%, 2.4%, 3.2%, and 4% of DEE was blended with biodiesel/diesel. The IS standards are followed for investigating the various properties of biodiesel blends. Property investigation results revealed that the increasing concentration of DEE reduces the density, viscosity, calorific value, flash point with increase in cetane number. All the prepared blends are examined on water-cooled diesel engine at six distinct loads and constant engine speed. The investigation revealed that the BTE (brake thermal efficiency) increased by 16.06% while BSFC (brake specific fuel consumption) decreased by 4.12% for 0.8% concentration of DEE in a blend when contrasted with diesel. All tested fuel shows nearly the same trend of BSEC at all loading conditions and compression ratios. Further, the CI engine fueled with biodiesel-DEE-diesel blends has shown 20.41%, 34.69%, and 23.33% a maximum reduction in CO, HC, and NOx emissions as compared to diesel fuel at notable working conditions. The CO₂ emission reduced in ternary blends due to lower carbon content in the blend. It can be noted that the minimum 0.8% concentration of DEE at CR15 in the ternary blend provided significant increment in BTE as 16.06%, with a 4.12% reduction in BSFC while CO, HC and NOx emissions minimized by 15.07%, 3.45%, and 14.70% than that of diesel fuel. In minimum concentration of DEE, the A0.8B19.2 blend provided luminous results in both performance and emission characteristics at CR15.

The miniaturisation of systems has widely attracted researchers to contribute to the thermal performance enhancement utilising efficient heat transfer devices. Pulsating heat pipe (PHP) is an inimitable passive two-phase energy conversion/transport device capable of transferring extensive heat energy by oscillating liquid slugs and vapour plugs from hot to cold areas suitable for the management of generation of heat in electronics. Several theoretical, experimental and visualisation studies are made on PHP to understand operational mechanisms and to arrive at optimal conditions. Although PHP has potential application in the field of heat management, its effective utilisation is limited due to complex operational mechanisms.It is observed that PHPs are effective and reliable devices for utilisation in numerous energy systems. It is observed that PHPs are effective and reliable devices for utilisation in numerous energy systems. Advanced research is directed towards numerical simulations on the evaluation of PHP performance with non-conventional working fluids. It is found that the use of ternary hybrid nanofluid in PHP has scope for research work. The objective of this paper is to review the existing methodologies for enhancing the PHP overall performance and its applications.

A study of the existing literature on the effects of diethyl ether with different biodiesels such as Fish, Neem, Calophyllum Inophyllum, Cottonseed, and Soybean biodiesel was undertaken. Till date, no study related to the combined effects of repurpose used cooking oil biodiesel/diethyl ether/diesel blends and different compression ratios with different loading conditions has been reported in the literature. Moreover, the current study reveals that there are some major flaws in the existing scenario such as no reduction in harmful exhaust gases such as carbon dioxide, hydrocarbon, carbon monoxide, and nitrogen oxide. There is no noticeable improvement in the performance characteristics such as brake thermal efficiency and brake specific fuel consumption. This investigation has been carried out for controlling harmful emissions and improving the performance of the engine. The present study investigates the combined impact of compression ratios on emission and performance characteristics of a diesel engine using ternary blends in comparison with diesel. This study provides eco-friendly working conditions that result in fewer emissions with improved performance. The results show that a higher compression ratio is useful for minimizing nitrogen oxide emission, while a lower compression ratio is useful for minimizing carbon monoxide emission. CR16 works effectively with a higher proportion of diethyl ether (2.4 and 3.2%) and provides better results for minimizing emissions with improved performance. The following eco-friendly blends delivered lower emissions with improved performance. These blends are: A0.8_B19.2: CR16 and CR15; A1.6_B18.4: CR17 and CR16; A2.4_B17.6: CR16, CR15, and CR14; A3.2_B16.8: CR16 and CR15.

Biodiesel is a renewable energy source which is gaining prominence as an alternative fuel over fossil diesel for different applications. Due to their higher viscosity and lower volatility, biodiesels are blended with diesel in various proportions. B20 blends are viable and sustainable solutions in diesel engines with acceptable engine performance as they can replace 20% fossil fuel usage. Biodiesel blends are slightly viscous as compared with diesel and can be used in common rail direct injection (CRDI) engines which provide high pressure injection using an electronic control unit (ECU) with fuel flexibility. In view of this, B20 blends of three biodiesels derived from cashew nutshell (CHNOB (B20)), jackfruit seed (JACKSOB (B20)), and Jamun seed (JAMNSOB (B20)) oils are used in a modified single-cylinder high-pressure-assisted CRDI diesel engine. At a BP of 5.2 kW, for JAMNSOB (B20) operation, BTE, NOx, and PP increased 4.04%, 0.56%, and 5.4%, respectively, and smoke, HC, CO, ID, and CD decreased 5.12%, 6.25%, 2.75%, 5.15%, and 6.25%, respectively, as compared with jackfruit B20 operation.

Environmentally friendly, renewable, and green fuels have many benefits over fossil fuels, particularly regarding energy efficiency, in addition to addressing environmental and socioeconomic problems. As a result, green fuels can be used in transportation and power generating applications. Furthermore, being green can ably address the emission-related issues of global warming. In view of the advantages of renewable fuels, two B20 fuel blends obtained from methyl esters of cashew nutshell (CHNOB), jackfruit seed (JACKFSNOB), and jamun seed oils (JAMSOB) were selected to evaluate the performance of a common rail direct injection (CRDI) engine. Compatibility of the nozzle geometry (NG) and combustion chamber shape (CCS) were optimized for increased engine performance. The optimized CCS matched with an increased number of injector nozzle holes in NG showed reasonably improved brake thermal efficiency (BTE), reduced emissions of smoke, HC, and CO, respectively, while NOx increased. Further combustion parameters, such as ignition delay (ID) and combustion duration (CD) reduced, while peak pressure (PP) and heat release rates (HRR) increased at the optimized injection parameters. The CRDI engine powered with JAMSOB B20 showed an increase in BTE of 4–5%, while a significant reduction in HC and CO emissions was obtained compared to JACKFSNOB B20 and CHNOB B20, with increased NOx.