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The purpose of the Air Generation System is to provide a constant supply of conditioned fresh air to meet the necessary oxygen availability and to prevent carbon dioxide (CO2) concentrations for the occupants in an aircraft. The engine bleed energy or electrical load energy consumed towards this circumstance accounts to be approx. 5% of total fuel burn and in turn, contributes to the global emissions of greenhouse gases. This paper studies the improvement areas of the present conventional system such as fuel burn consumption associated with an aircraft environmental control system (ECS) depending on, the amount of bleed and ram air usage, electric power consumption. Improved systems for propulsion, power generation, sustainability, hybridization, and environmental control can be desirable for an aircraft.

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.

The crankshaft translates the reciprocatory motion of the piston into rotary motion. A flywheel is generally connected to the crankshaft to reduce the vibrating characteristic of four stroke cycle. Counterweights are added for each reciprocating piston to provide engine balance while operating. Gasoline engines have curtailed compression ratio therefore shorter stoke length as a deduction have higher RPM in comparison to diesel counterpart. A crankshaft is subjected to enormous stresses, potentially equivalent of several tones of force. Failure of the crankshaft is predominantly due to violent vibrations, insufficient lubrication, excessively pressurized cylinder. This research aims to examine the stress subjected to acute points on a crankshaft. Three dimension model of 4 stroke single cylinder engine crankshaft is modeled using SolidWorks v18. End conditions were applied taking into consideration the engine mountings of the crankshaft.

The power generation, agriculture, and transportation sectors are dominated by diesel engines due to better thermal efficiency and durability. Diesel engines are also a major contributor to the air pollutants such as NOx and particulate matter. Acetone-butanol-ethanol (ABE) is considered a promising alternative fuel as it emits less pollutants compared to conventional fuels. In current work, the ABE used was of the ratio (3:6:1) and four samples were prepared for engine trial ABE (10%90%diesel), ABE (20%80%diesel), ABE (30%70%diesel) and ABE (40%60%diesel). Their physio-chemical properties like kinematic viscosity, density, specific gravity and calorific value were checked and tested on compression ignition engine at different operating parameters. The experimental work was conducted upon Kirloskar 4-stroke single cylinder, vertical, air-cooled 661cc compression ignition engine at different speeds and loads.

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.

Biodiesel is a potential substitute for diesel and extensive research is carried in India on production and utilization of biodiesel from a variety of edible/non-edible, animal fat and waste oils. However, issues like stability, clogging, increased NOx, and high consumption rate etc. are some of the critical issues which are associated with long-term use of these alternative fuels in a diesel engine. The recent developments in science and technology may have concreted a method to create nano measure vigorous resources that have incredible benefits to micron sized constituents. Nano liquids may be a fresh period of compact-fluid complex constituents comprising of nano sized concrete elements disseminated into a base liquid. The present study investigates the effect of doping metal oxides nanoparticles with waste fish oil-based biodiesel. For the present study, the blends of fuel are prepared by using 30ppm each of titanium dioxide and alumina nanoparticles respectively.

Diesel engine widely uses in India in farming, transportation, and industrial sectors due to higher thermal efficiency, robust construction and heavy load carrying capacity. However, diesel engine emits a large number of gaseous emissions and particulate matter which caused serious detrimental environmental consequences and health hazards. The use of biofuel has shown a positive impact in resolving these issues of environmental degradation. India is also a net importer of petroleum-derived fuels and a substantial amount in precious foreign exchange is spent for this. In the last three decades in India, a lot of research work on renewable diesel-like fuels have been carried out, and the most promising of them is biodiesel. However,Biodiesel suffers from the drawback of relatively higher kinematic viscosity. But higher alcohols such as n-butanol and n-octanol could be blended with the biodiesel to bring its properties similar to diesel fuel.

Heat exchangers are widely used in various transportation, industrial, or domestic applications such as thermal power plants, means of heating, transporting and air conditioning systems, electronic equipment and space vehicles. In all these applications improvements in the efficiency of the heat exchangers can lead to substantial cost, space and material savings. Hence considerable research work has been done in the past to seek effective ways to improve the efficiency of heat exchangers. In this paper the effect of natural convection is justified between exterior solid wall surfaces and the surrounding air inside the enclosure. Designing of electronic devices, heavy industrial equipments such as boilers, turbines etc. and building aerodynamics are some of the real world application associated with this study.

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 use of alternative fuel has many advantages and the main ones are its renewability, biodegradability with better quality exhaust gas emission, which do not contribute to raise the level of carbon dioxide in the atmosphere. The use of non-edible vegetables oils as an alternative fuels for diesel engine is accelerated by the energy crisis due to depletion of resources and increase in environmental problems. In Asian countries like India, great need of edible oil as a food so cannot use these oils as alternative fuels for diesel engine. However there are many issues related to the use of vegetable oils in diesel engine that is high viscosity, low calorific value, high self-ignition temperature etc. Jatropha curcas has been promoted in India as a sustainable substitute to diesel fuel. This research prepared micro emulsions of ethanol and Jatropha vegetable oil in different ratio and find out the physico-chemical parameters to compare with mineral diesel oil.

The increment in the application of fossil fuels is leading the world into a catastrophic state both environmentally and economically. Current demand for fuels exceeds its imminent supply and rather sooner than later energy demands will have to shift towards non-conventional fuels to cope with the situation. With constant developments in the automotive sector, several solutions have been found but none have been as good as gasoline to substitute it in the commercial market. One such solution being compressed air might solve this global fuel crisis, which serves a glowing advantage of being cheaper and greener as it produces zero tail-pipe emissions, and can help in decreasing automobile’s contribution to global warming. Though the potential energy stored in the compressed air limits its application to light duty vehicles and still there will be a need for other alternative solutions for the heavy duty vehicles in order to relieve the pressure from the fossil fuels.

Rapid depletion in fuel resources owing to the low efficiency of current automobiles has been a major threat to future generations for fuel availability as well as environmental health. Advanced new generation of internal combustion (IC) engines are expected to have far better emissions levels both gaseous (NOx and CO) and particulate matter, at the same time having far lower fuel consumption on a wide range of operating condition. These criteria could be improved having a homogeneous combustion process in an engine. Homogeneous mixing of fuel and air in HCCI leads to cleaner combustion and lower emissions. Since peak temperatures are significantly lower than in typical SI engines, NOx levels and soot are reduced to some extent. Because of absence of complete homogeneous combustion but quasi homogeneous combustion present in HCCI, there is still a possibility of further reducing the emissions as well as enhancing the engine performance.

The diesel engine has for many decades now assumed a leading role in both the medium and medium-large transport sector due to their high efficiency and ability to produce high torque at low RPM. Furthermore, energy diversification and petroleum independence are also required by each country. In response to this, biodiesel is being considered as a promising solution due to its high calorific value and lubricity conventional petroleum diesel. However, commercial use of biodiesel has been limited because of some drawbacks including corrosivity, instability of fuel properties, higher viscosity, etc. Biodiesel are known for lower CO, HC and PM emissions. But, on the flip side they produce higher NOx emissions. The addition of alcohol to biodiesel diesel blend can help in reducing high NOx produced by the biodiesel while improving some physical fuel properties.

Recent scenario of fossil fuel depletion as well as rising emission levels has witnessed an ever aggravating trend for decades. The solution to the problems has been addressed by investments and research in the field of fuels; such as the use of cleaner fuels involving biodiesel, alcohol blends, hydrogen and electric drivelines, as well as improvement in traditional technologies such as variable geometry systems, VVT load control strategies etc. The developments have highlighted the enormous potential present in such systems in terms of maximizing engine efficiency and emission reductions. The present paper aims at designing and implementing an intake runner system for a CI engine capable of providing flexibility with variations in operating conditions. Primarily, the design aims at altering the air flow phenomenon within the primary intake of the engine by inducing swirl in the runner through a secondary runner.

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.

The continued reliance on fossil fuel energy resources is not sufficient to cater to the current energy demands. The excessive and continuous use of crude oil is now recognized as unviable due to its depleting supplies and elevating environmental degradation by increased emissions from automobile exhaust. There is an urgent need for a renewable and cleaner source of energy to meet the stringent emission norms. Hythane is a mixture of 20% hydrogen and 80% methane. It has benefits of low capital and operating costs and is a cleaner alternative than crude oil. It significantly reduces tailpipe emissions and is the cheapest way to meet new emission standards that is BS-IV. Hythane produces low carbon monoxide (CO), carbon dioxide (CO2) and hydrocarbons (HC) on combustion than crude oil and helps in reduction of greenhouse gases.

Non-edible vegetable oils have a huge potential for biodiesel production and also known as second generation feedstock’s. Biodiesel can be obtained from edible, non-edible, waste cooking oil and from animal fats also. This paper focuses on production of biodiesel obtained from mixture of sesame (Sesamum indicum L.) oil and neem (Azadirachta indica) oil which are easily accessible in India and other parts of world. Neem oil has higher FFA content than sesame oil. Biodiesel production from neem oil requires pretreatment neutralization procedure before alkali catalyzed Trans esterification process also it takes large reaction time to achieve biodiesel of feasible yield. Neem oil which has very high FFA and sesame oil which has low FFA content are mixed and this mixture is Trans esterified with no pre-treatment process using molar ratio of 6:1.Fuel properties of methyl ester were close to diesel fuel and satisfied ASTM 6751 and EN 14214 standards.

The Automobile industry is under great stress due to greenhouse gas emissions and health impacts of pollutants. The rapid decrease of fossil fuels has promoted the development of engine designs having higher fuel economy. At the same time, these designs keep the stringent emission standards in check without sacrificing brake power. Variable Compression Ratio (VCR) is one such measure. This work reviews the technological advancements in the design of a VCR engine. VCR engines can minimize possible risks of irregular combustion while optimizing Brake specific fuel consumption towards higher power and torque. An increase in fuel economy is seen for VCR naturally aspirated engines when coupled with downsizing. In addition to this, emissions of carbon dioxide decreases due to effective utilization of fuel at high loads. Since the first VCR design, there have been various modifications and improvements in VCR engine design.

The growing energy demand and limited petroleum resources in the world have guided researchers towards the use of clean alternative fuels like alcohols for their better tendency to decrease the engine emissions. To comply with the future stringent emission standards, innovative diesel engine technology, exhaust gas after-treatment, and clean alternative fuels are required. The use of alcohols as a blending agent in diesel fuel is rising, because of its benefits like enrichment of oxygen, premixed low temperature combustion (LTC) and enhancement of the diffusive combustion phase. Several researchers have investigated the relationship between LTC operational range and cetane number. In a light-duty diesel engine working at high loads, a low-cetane fuel allowed a homogeneous lean mixture with improved NOx and smoke emissions joint to a good thermal efficiency.

The danger posed by climate change and the striving for securities of energy supply are issues high on the political agenda these days. Governments are putting strategic plans in motion to decrease primary energy use, take carbon out of fuels and facilitate modal shifts. Man's energy requirements are touching astronomical heights. The natural resources of the Earth can no longer cope with it as their rate of consumption far outruns their rate of regeneration. The automotive sector is without a doubt a chief contributor to this mayhem as fossil fuel resources are fast depleting. The harmful emissions from vehicles using these fuels are destroying our forests and contaminating our water bodies and even the air that we breathe. The need of the hour is to look not only for new alternative energy resources but also clean energy resources. Hydrogen is expected to be one of the most important fuels in the near future to meet the stringent emission norms.