The substitution of mineral oil with vegetable oil as a lubricant in a CI engine is explored in this study. The experiments have been conducted with neat pongamia oil, blend of pongamia oil and mineral oil (50% V/V), and neat mineral oil as lubricants; and neat pongamia oil, blends of pongamia oil, and diesel in proportions of 20, 40, and 100, neat pongamia ester, and blends of pongamia ester and diesel in proportions of 20, 40, and 100 as fuel. For various combinations of fuel and lubricant, NOx, smoke, CO, HC, BSEC, EGT, and friction power were compared. It was found that there was no difficulty in operating the engine using the lubricants considered in this work. Further, it was found that the best results were recorded for the fuel-lubricant combination of neat pongamia as both fuel and lubricant.

The paper presents an analysis of the performance of a Proton Exchange Membrane (PEM) fuel cell, which is equipped with a flow field design featuring dual inlets and outlets, while operating under conditions of excess stoichiometry. These experiments were conducted using a fuel cell system connected to a station that allowed for the precise adjustment of gas flow rates. During the initial phase of experimentation, various proportions of excess oxygen were systematically applied, while maintaining constant hydrogen flow rates of 80 mL/min and 100 mL/min. Particularly noteworthy, for the case of a 100 mL/min hydrogen gas flow rate and the optimized excess oxygen proportion of 150%, further experiments were undertaken to ascertain the ideal humidification conditions. The outcomes of these experiments revealed that a hydrogen gas flow rate of 100 mL/min consistently outperformed the 80 mL/min flow rate in terms of fuel cell performance. Moreover, it was observed that the introduction of excess oxygen significantly improved performance, up to a 50% oxygen proportion for the 80 mL/min hydrogen flow rate and up to a 150% proportion for the 100 mL/min hydrogen flow rate. One intriguing observation pertained to the influence of humidification. Specifically, it was found that the utilization of a humidification temperature of 100°C, or the absence of humidification altogether, resulted in notably diminished power output. In contrast, intermediate humidification temperatures of 60°C, 70°C, 80°C, and 90°C consistently yielded identical maximum power points (MPP) when combined with a 150% excess oxygen supply and a hydrogen flow rate of 100 mL/min. The twin inlet-twin outlet flow field provides a slight advantage over the conventional serpentine flow field in the overall analysis.

The cycle-by-cycle fluctuations in peak pressure of combustion in a CI engine were studied for lower and higher blends of diesel and ester, and water-in-ester emulsions, at four injection timings and three injection pressures using coefficient of variation. The sunflower ester-diesel blends are found to have lower cycle-by-cycle fluctuations than pongemia ester-diesel blends. The fluctuations are found to be higher than that of diesel for higher blend proportions of ester. The water-in-ester emulsion show higher cycle-by-cycle fluctuations than that of ester-diesel blends. In most cases, the Brake specific energy consumption is also found to be higher where the coefficient of variation has higher values.

Hydrogen fuel cells are gaining popularity in power-consuming devices due to their zero-emission characteristics. However, ohmic resistance, which arises from the resistance to electron flow through the electrodes and external circuit, can cause reduced efficiency and voltage drops in a fuel...