The protection of the environment and pollution control are issues of paramount importance. Researchers today are engrossed in mitigating the harmful impacts of petroleum waste on the environment. Lubricating oils, which are essential for the smooth operation of engines, are often disposed of improperly after completing their life. In the experimental work presented in this paper, deteriorated engine oil was regenerated using the acid treatment method and was reused in the engine. The comparison of the properties of reused oil, the engine’s performance, and the emissions from the engine are presented. The reuse of regenerated oil, the evaluation of performance, and emissions establish the usefulness of the regeneration of waste lubricating oil. For the used oil, total acid number (TAN), specific gravity, flash point, ash content, and kinematic viscosity changed by 60.7%, 6.7%, 4.4%, 96%, and 15.5%, respectively, compared with fresh oil. The regeneration partially restored all the lost lubricating oil properties. The performance parameters, brake power (BP), brake specific fuel consumption (BSFC), and exhaust gas temperature (EGT) improved with regenerated oil in use compared with used oil. The emissions CO and NO_X contents for acid-treated oil were 9.7% and 17.3% less in comparison with used oil, respectively. Thus, regenerated oil showed improved performance and oil properties along with significantly reduced emissions when employed in an SI engine.

Alcoholic fuels have recently come to light as a sustainable source for powering today’s vehicles. Various studies have investigated the effects of alcoholic fuels on engine efficiency and emission characteristics. However, scarce literature is available for their effects on lubricant. Therefore, propanol-gasoline fuel mixtures, with concentrations of 9% (P9) and 18% (P18) propanol, were made to compare their engine characteristics and lubricating oil condition with that of pure gasoline (0 percent propanol (P0)). To determine the rate of deterioration, the characteristics of the lubricating oil were evaluated after 100 h of engine operation, as suggested by the manufacturer. When compared with unused lube oil, P18 showed reductions in flash point temperature and kinematic viscosity of 14% and 36%, respectively, at 100 °C. For P18, which contains Fe (27 PPM), Al (11 PPM), and Cu (14 PPM), the highest wear element concentrations in the lubricating oil were found. The moisture in the degraded oil was well within the allowable limit for the three fuel mixtures. With the increase in propanol percentage in the propanol-gasoline blend, the engine performance was increased. Compared to P9 and P0, P18 had the partially unburned emissions.

The transportation sector stands at the forefront of global challenges, where its significant contribution to greenhouse gas emissions and air pollution has become an urgent matter demanding immediate attention. For addressing these compelling concerns and leading the automotive industry toward a sustainable future, it is, therefore, imperative to explore the realm of alternative fuel that can effectively mitigate the environmental impact of automobiles. Methanol, a renewable alternative fuel, has gathered quite an attention due to its potential to be used as a wonderful alternative to neat gasoline in spark ignition engines. However, there are some core challenges that must be addressed to utilize methanol on a commercial scale in the transport sector. These core challenges include cold start issues, enhanced NOx emissions, 100% methanol utilization, transportation concerns and lubricant oil deterioration. In this chapter, these challenges along with their potential solutions have been discussed in detail. Moreover, different techniques such as artificial neural network and response surface methodology have been discussed to predict and optimize the usage of methanol in SI engines. The adoption of methanol, as an alternative to gasoline, will help us achieve some important sustainable development goals, thus fulfilling the promise of a sustainable future for the upcoming world.