Search Results

Diesel engines are employed particularly in the field of heavy transportation and agriculture on account of their higher thermal efficiency and durability. As these engines, are the backbones of contemporary global transportation and accounts a 30% of world's energy consumption, which is second highest after the industrial sector. Therefore, the fossil fuel consumption becomes the prime concern. Following the global energy crisis and the increasingly stringent emission norms, the search for alternative renewable fuels has intensified. Currently, biodiesel (BD) has been identified as the most attractive and practical choice to replace fossil fuel as the main source of energy, due to the similarity in the properties with conventional diesel. However, its development and application have been hindered by the high cost of required feedstock. Therefore, in recent years, researchers have been seeking the alternative sources of non-edible oil which are economical.

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.

Rapid depletion of fossil fuels is urgently demanding an extensive research work to find out the viable alternative fuel for meeting sustainable energy demand without any environmental impact. In the future, our energy systems will need to be renewable, sustainable, efficient, cost-effective, convenient and safe. Therefore, researchers has shown interest towards alternative fuels like vegetable oils, alcohols, LPG, CNG, Producer gas, biogas in order to substitute conventional fuel i.e. diesel used in compression ignition (CI) engine. However, studies have suggested that trans-esterified vegetable oils retain quite similar physico-chemical properties comparable to diesel. Besides having several advantages, its use is restricted due to higher emissions i.e. NOx, CO, HC and deposits due to improper combustion. Hence, there is a need of cleaner fuel for diesel engines for the forthcoming stringent emissions norms and the fossil depletion.

Due to high energy demand and limited availability of fossil fuels, the energy necessity becomes a point of apprehension as it results in hike of fuel prices. It is essential to develop renewable energy resources while considering the impact on environment. In the last decade, demand of alternative fuels has increased a lot. Therefore, researchers have already started working on the aim of developing a green fuel to overcome the future energy demand. And as we know that the biodiesel is generally prepared from the non-edible and renewable resources thus, it can be among the competitive alternative future fuels. Besides that, it does not require any prior engine modifications for its usual advantage among other alternative fuels while using it within certain boundaries. However, the process biodiesel production is in itself time consuming which increases the cost of production while decreasing the yield.

Primary energy sources can be divided into non-renewable and renewable. The over-exploration of non-renewable sources for energy availability imposes considerable impacts on the environment. Reducing the use of fossil fuels would significantly reduce the carbon dioxide emissions and other pollutants produced. The future drift for sustainable production of renewable energy is cautiously thoughtful for it has been increasingly understood that first generation biofuels, majorly produced from food crops that are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-edible feedstock such as microalgae, which potentially offers greatest opportunities in the longer term. Microalgae are considered a very promising feedstock for biodiesel production due to their very high yield and their no competition with food crops.

Internal combustion engines are the backbone of contemporary global transportation. But the major drawbacks associated with them, are the exhaust gases. These include carbon monoxide (CO), unburned hydrocarbons (UBHC), oxides of nitrogen (NOx), odor, particulate matter (PM) etc. Among them the emissions of oxides of nitrogen (NOx) and the particulate matter are the reasons of serious concern. For NOx reduction in recent developing technologies, diesel water emulsion was found the best approach for the existing engines by researchers. In the present study, performance and emission statistics of a diesel engine using diesel water emulsion operating at different compression ratios from 17:1 to 18:1 was performed. Stable Emulsions were prepared with 5%, 10%, 15%, 20% and 25 % (v/v) water concentration with variable agitation speed ranging from 5000-15000 rpm along with two surfactants. Various physico-chemical properties of emulsions were tested for all six samples including diesel.

Globally, transportation is the second largest energy consuming sector after the industrial sector and is completely dependent on petroleum products and alternative technologies. So, fossil fuel consumption for energy requirement is a primary concern and can be addressed with the fuel consumption reduction technologies. Transportation sector is mainly using diesel engines because of production of high thermal efficiency and higher torque at lower RPM. Therefore, diesel consumption should be targeted for future energy security and this can be primarily controlled by the petroleum fuel substitution techniques for existing diesel engines. Some of the fuel, which includes biodiesel, alcohol-diesel emulsions and diesel water emulsions etc. Among which the diesel water emulsion (DWE) is found to be most suitable fuel due to reduction in particulate matter and NOx emission, besides that it also improves the brake thermal efficiency.