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Turboexpansion is a concept which is aimed at reducing the fuel consumption of pressure-charged combustion engines by providing over-cooled air to the engine prior to its induction in the combustion chamber. The performance of the engine is dependent on intake charge density which is preferred to be high at reduced charge air temperature. This becomes achievable through a cooling system known as a turbo expander which expands a high-pressure gas to produce work that is usually employed to drive a compressor. Though, initially used for the purpose of refrigeration in industries, for the past few decades various researches have proved its efficiency in internal combustion engines. In gasoline engines, it is usually employed to extend the knock limit and reduce carbon emissions. Also, an extension to the knock limit allows several improvements in parameters such as increased specific output, an increase in compression ratio and a reduction in the fuel consumption of the engine.

The interest of using alternative fuels in diesel engines has been accelerated exponentially due to a foreseen scarcity in world petroleum reserves, increase in the prices of the conventional fossil fuels and restrictions on exhaust emissions such as greenhouse gases from internal combustion (IC) engines initiated by environmental concerns. The constant trade-off between efficiency and emissions should be in proper balance with the conventional fuels in a fuel design process for future combustors. Unlike gasoline and diesel, alcohols act as oxygenated fuels. Adding alcohols to petroleum products allows the fuel to combust properly due to the presence of oxygen, which enhances premixed combustion phase, improves the diffusive combustion phase which increases the combustion efficiency and reduces air pollution. The higher activation energy of alcohols leads to better resistance to engine knocking that allows higher compression ratios and greater engine thermal efficiencies.

Increased dependency on fossil fuels has led to its depletion as well as affected the environment adversely. Moreover, increasing crude oil prices is pressurizing vehicle manufacturers to invent new technology so as to increase fuel economy and at the same time to keep emissions under control. Hydrogen has gained popularity not just in terms of being an abundant alternative but also due to being a very clean propellant. In the present investigation, hydrogen boosting has been performed on an SI engine running on gasoline-methanol and ethanol-gasoline blends to determine the additional advantages of the same compared to pure gasoline operation. The engine selected for experimental analysis is a single cylinder, air cooled spark ignition engine that has been modified for hydrogen injection in the intake manifold prior to the port with the injection timing being held constant throughout the experiment.

For the last decade, the lubricant industry has been trying to formulate biodegradable lubricants with technical characteristics superior to those based on petroleum. A renewable resource, mahua oil, is good alternative to mineral oil because of its environmentally friendly, non toxic and readily biodegradable nature. The triacylglycerol structure of mahua oil is amphiphilic in character that makes it an excellent candidate as lubricant and functional fluid. It is also very attractive for industrial applications that have potential for environmental contact through accidental leakage, dripping or generates large quantities of after-use waste materials requiring costly disposal. Vegetable oil in its natural form has limited use as industrial fluids due to poor thermo-oxidation stability, low temperature behavior and other tribochemical degrading processes.

The transportation sector faces great and urgent challenges, including climate impacts of greenhouse gas emissions, local health impacts of criteria pollutants, and political & economic impacts of petroleum dependence. While several revolutionary solutions are being developed to reduce the impact of motor vehicles, such as increased fuel economy standards and accelerated adoption of hybrid vehicles, revolutionary new approaches must also be evaluated. One such opportunity is found in Compressed Air Engine (CA Engine), which is powered solely by compressed air stored in a vehicle on-board pressurized tank. Proponents of this technology claim CA Engines are greener and cheaper to operate, since they do not consume fossil fuels and produce zero tail-pipe emissions, while offering the power and performance needed for light-duty vehicle use.

Gasoline has been the major fuel in transportation, its good calorific value and high volatility have made it suitable for use in different injection methods. The drastic increase in use of carbon based fuels has led to increase in harmful emissions, thus resulting in implementation of stricter emissions norms. These harmful emissions include carbon monoxide and NOx. To meet the new norms and reduce the harmful emissions, better techniques have to be implemented to achieve better combustion of gasoline and reduce the amount of carbon monoxide in the exhaust. One such way of doing this is by enriching gasoline with hydrogen. Due to its low activation energy and high calorific value, the high energy released from hydrogen can be used to achieve complete combustion of gasoline fuel. However, there are certain drawbacks to the use of hydrogen in spark ignition engine, knocking and overheating of engine parts being the major problems.

Globally, the demand for energy is increasing due to both increase in population and enhancement in the lifestyle of people. Most of the energy demand at present is met from fossil fuels, which are not only exhaustible but also a threat to the environment. Various routes of sustainable energy resources are being explored to address the above-mentioned issues and fuel made from used tyre may be one of the promising options. India is one of the fastest growing economies and every year 10 million new vehicles are registered. Due to poor road conditions, nearly fourfold tyres of this number are dumped as waste. This large stock of dumped tyres are non-biodegradable and creates other problems like a breeding site for mosquitos, or source of pollution in case of accidental fire. In order to cope with the large pile-up of used tyres, pyrolysis of these tyres could be a sustainable route.

In view of the rapid depletion, increasing prices and uneven distribution of conventional petroleum fuels; the interest in the use of alternative fuels has increased exponentially. Fuels such as biodiesel & alcohol have been evaluated both at experimental and commercial scale due to improved emission characteristics as compared to conventional fuels. Alcohols are oxygenated and result in improving the engine performance. As a blend with conventional gasoline, the alcohols enhance the premixed and diffusive combustion phase which improves the combustion efficiency. The present investigation evaluates studies on stability and homogeneity along with physicochemical properties like density, viscosity, calorific value, copper-strip corrosion and solubility at room temperature of Propan-2-ol and gasoline blends. Comprehensive engine trials on unmodified petrol engine fuelled with blends of Propan-2-ol and gasoline blends in the proportions of 5, 10, 15 and 20% by volume have been conducted.

The world today is facing severe oil crisis and environmental pollution, thus there is a great urgency of developing and applying bio based products as a substitute to mineral oil based products. Rapid industrialization and automation in the last decade has increased the demand of mineral oil based lubricant that will get exhausted in the years to come. Also in addition to the above fact, the biodegradability of mineral-oil based lubricants is around 25% maximum. About 50% of all lubricants sold worldwide end up in the Environment. Due to extensive use of mineral oil based lubricants, several environmental issues such as surface water and groundwater contamination, Air pollution, soil contamination, agricultural product and food contamination are emerging very rapidly. This has led the researchers to look for plant oil based bio- lubricant as an alternative to mineral oil based lubricant.

The economics of operating internal combustion engines in cars, buses and other automotive equipment is heavily affected by friction and wear losses caused by abrasive contaminants. As such, dust is a universal pollutant of lubricating oils. Road dust consists of depositions from vehicular and industrial exhausts, tire and brake wear, dust from paved roads or potholes, and from construction sites. Present research investigates the influence of dust powder of size 5 μm-100 μm as contaminant in SAE 20W-40 lubricant on the relative motion of a plane surface over the other having circular surface in contact. A pin-on-disk setup as per ASTM G99 has been used to conduct the experiments, firstly at increasing rpm keeping constant load of 118 N, and secondly by increasing loads, keeping rpm constant at 1000. The contaminated lubricant has been used to study its influence on friction and wear rate at the interface of pin of 12 mm diameter and disk at track diameter of 98 mm.

The need for advanced lubricants is increasing rapidly due to the current wide range of operational usage, i.e., high loads and speeds of motion between friction pairs, broader temperature range, and the overall requirements for increased reliability and service life of machinery. It is essentially important to develop specialized anti-friction and anti-wear materials that will help in preventing wear and decreasing friction, thereby saving fuel and electricity. Simultaneously, such materials are also expected to reduce vibration, noise and maintenance of machine parts. Thus, the research into extending the service life of such materials continues to be imperative. Nanoparticles (NPs) present a novel approach in this regard, as they can be used in lubricants in between two mating contact surfaces as a third body.