• Energy Research

In the transportation sector, the share of biofuels such as biodiesel is increasing and it is known that such fuels significantly affect NOx emissions. In addition to NOx emission from diesel engines, which is a significant challenge to vehicle manufacturers in the most recent emissions regulation (Euro 6.2), this study investigates NO2 which is a toxic emission that is currently unregulated but is a focus to be regulated in the next regulation (Euro 7). This manuscript studies how the increasing share of biofuels affects the NO2, NOx, and NO2/NOx ratio during cold-start (in which the after-treatment systems are not well-effective and mostly happens in urban areas). Using a turbocharged cummins diesel engine (with common-rail system) fueled with diesel and biofuel derived from coconut (10 and 20% blending ratio), this study divides the engine warm-up period into 7 stages and investigates official cold- and hot-operation periods in addition to some intermediate stages that are not defined as cold in the regulation and also cannot be considered as hot-operation. Engine coolant, lubricating oil and exhaust temperatures, injection timing, cylinder pressure, and rate of heat release data were used to explain the observed trends. Results showed that cold-operation NOx, NO2, and NO2/NOx ratio were 31-60%, 1.14-2.42 times, and 3-8% higher than the hot-operation, respectively. In most stages, NO2 and the NO2/NOx ratio with diesel had the lowest value and they increased with an increase of biofuel in the blend. An injection strategy change significantly shifted the in-cylinder pressure and heat release diagrams, aligned with the sudden NOx drop during the engine warm-up. The adverse effect of cold-operation on NOx emissions increased with increasing biofuel share.

In the transportation sector, the share of biofuels such as biodiesel is increasing and it is known that such fuels significantly affect NOx emissions. In addition to NOx emission from diesel engines, which is a significant challenge to vehicle manufacturers in the most recent emissions regulation (Euro 6.2), this study investigates NO2 which is a toxic emission that is currently unregulated but is a focus to be regulated in the next regulation (Euro 7). This manuscript studies how the increasing share of biofuels affects the NO2, NOx, and NO2/NOx ratio during cold-start (in which the after-treatment systems are not well-effective and mostly happens in urban areas). Using a turbocharged cummins diesel engine (with common-rail system) fueled with diesel and biofuel derived from coconut (10 and 20% blending ratio), this study divides the engine warm-up period into 7 stages and investigates official cold- and hot-operation periods in addition to some intermediate stages that are not defined as cold in the regulation and also cannot be considered as hot-operation. Engine coolant, lubricating oil and exhaust temperatures, injection timing, cylinder pressure, and rate of heat release data were used to explain the observed trends. Results showed that cold-operation NOx, NO2, and NO2/NOx ratio were 31-60%, 1.14-2.42 times, and 3-8% higher than the hot-operation, respectively. In most stages, NO2 and the NO2/NOx ratio with diesel had the lowest value and they increased with an increase of biofuel in the blend. An injection strategy change significantly shifted the in-cylinder pressure and heat release diagrams, aligned with the sudden NOx drop during the engine warm-up. The adverse effect of cold-operation on NOx emissions increased with increasing biofuel share.

Energy is a basic requirement for development in the world. The continuously rising demand for energy resources and the fast depletion of fossil fuel is raises researcher's concern to focus on alternative sources of energy that can replace the shortage of fossil fuels soon. Biodiesel is recognized as one of the potential alternative renewable energy fuels that can be easily available in a wide range in every part of the world. This paper reviews biodiesel's prospect and focuses on the different fuel properties (physicochemical) of 100 biodiesels from first-, second- and third-generation followed by the evaluation of CI engine characteristics. It has been observed that the fuel properties of first-, second- and third-generation biodiesel are compatible with the ASTM standards. The present paper discussed the potential of various generations of biodiesel feedstocks from production perspectives. This paper also examined many aspects of these feedstocks which include different biodiesel feedstock sources, biodiesel conversion technology, and second-generation biodiesel performance and emission characteristics. Most of the studies showed that biodiesel derived from plant feedstock is costly than diesel. Thus, more influence is to be given to non-edible sources. However, the engine characteristics are shown promising behavior with biodiesel and a slight increase in NOX is also reported on using various biodiesel.

Energy is a basic requirement for development in the world. The continuously rising demand for energy resources and the fast depletion of fossil fuel is raises researcher's concern to focus on alternative sources of energy that can replace the shortage of fossil fuels soon. Biodiesel is recognized as one of the potential alternative renewable energy fuels that can be easily available in a wide range in every part of the world. This paper reviews biodiesel's prospect and focuses on the different fuel properties (physicochemical) of 100 biodiesels from first-, second- and third-generation followed by the evaluation of CI engine characteristics. It has been observed that the fuel properties of first-, second- and third-generation biodiesel are compatible with the ASTM standards. The present paper discussed the potential of various generations of biodiesel feedstocks from production perspectives. This paper also examined many aspects of these feedstocks which include different biodiesel feedstock sources, biodiesel conversion technology, and second-generation biodiesel performance and emission characteristics. Most of the studies showed that biodiesel derived from plant feedstock is costly than diesel. Thus, more influence is to be given to non-edible sources. However, the engine characteristics are shown promising behavior with biodiesel and a slight increase in NOX is also reported on using various biodiesel.

NOx emissions from diesel engines are a concern from both environmental and health perspectives. Recently this attention has targeted cold-start emissions highlighting that emission after-treatment systems are not effective in this period. Using a 6-cylinder, turbocharged, common-rail diesel engine, the current research investigates NOx emissions during cold-start using different engine performance parameters. In addition, it studies the influence of waste lubricating oil on NOx emissions introducing it as a fuel additive (1 and 5% by volume). To interpret the NOx formation, this study evaluates different parameters: exhaust gas temperature, engine oil temperature, engine coolant temperature, start of injection/combustion, in-cylinder pressure, heat release rate, maximum in-cylinder pressure and maximum rate of pressure rise. This study clarified how cold-start NOx increases as the engine is warming up while in general cold-start NOx is higher than hot-start. Results showed that in comparison with warmed up condition, during cold-start NOx, maximum in-cylinder pressure and maximum rate of pressure rise were higher; while start of injection, start of combustion and ignition delay were lower. During cold-start increased engine temperature was associated with decreasing maximum rate of pressure rise and peak apparent heat release rate. During cold-start NOx increased with temperature and it dropped sharply due to the delayed start of injection. This study also showed that using waste lubricating oil decreased NOx and maximum rate of pressure rise; and increased maximum in-cylinder pressure. NOx had a direct correlation with the maximum rate of pressure rise; and an inverse correlation with the maximum in-cylinder pressure.

NOx emissions from diesel engines are a concern from both environmental and health perspectives. Recently this attention has targeted cold-start emissions highlighting that emission after-treatment systems are not effective in this period. Using a 6-cylinder, turbocharged, common-rail diesel engine, the current research investigates NOx emissions during cold-start using different engine performance parameters. In addition, it studies the influence of waste lubricating oil on NOx emissions introducing it as a fuel additive (1 and 5% by volume). To interpret the NOx formation, this study evaluates different parameters: exhaust gas temperature, engine oil temperature, engine coolant temperature, start of injection/combustion, in-cylinder pressure, heat release rate, maximum in-cylinder pressure and maximum rate of pressure rise. This study clarified how cold-start NOx increases as the engine is warming up while in general cold-start NOx is higher than hot-start. Results showed that in comparison with warmed up condition, during cold-start NOx, maximum in-cylinder pressure and maximum rate of pressure rise were higher; while start of injection, start of combustion and ignition delay were lower. During cold-start increased engine temperature was associated with decreasing maximum rate of pressure rise and peak apparent heat release rate. During cold-start NOx increased with temperature and it dropped sharply due to the delayed start of injection. This study also showed that using waste lubricating oil decreased NOx and maximum rate of pressure rise; and increased maximum in-cylinder pressure. NOx had a direct correlation with the maximum rate of pressure rise; and an inverse correlation with the maximum in-cylinder pressure.

The wheel was the first form of transportation developed by early people. Increasing population, longer distances, and shorter travel times need more cheap, faster modes of transportation. Environmental issues were never taken into account when choosing the most cost-effective mode of public transportation. Consequently, in the face of global pollution and warming restrictions, all stakeholders choose modes of transportation with little environmental impact. This has led to the development of sustainable transportation infrastructure, particularly in a country as rapidly developing as India. This paper examines the present situation, legislation, and grading systems for sustainable transportation in India and other developing nations. Furthermore, comparisons of India with developing nations of various continents in different aspects are also present. The difference in cost between a private car and a public vehicle indicates which form of transportation should be chosen. The challenges linked with urban and rural Indian roadways are explored, as well as their respective solutions. In order to accomplish sustainable transportation, traffic density and driver conduct are also considered. This study emphasises that sustainability is not just achieved through the use of cleaner fuel or the modification of road materials, although these are vital. Road design, regulatory changes, psychological behaviour, and transit safety are also crucial.

The wheel was the first form of transportation developed by early people. Increasing population, longer distances, and shorter travel times need more cheap, faster modes of transportation. Environmental issues were never taken into account when choosing the most cost-effective mode of public transportation. Consequently, in the face of global pollution and warming restrictions, all stakeholders choose modes of transportation with little environmental impact. This has led to the development of sustainable transportation infrastructure, particularly in a country as rapidly developing as India. This paper examines the present situation, legislation, and grading systems for sustainable transportation in India and other developing nations. Furthermore, comparisons of India with developing nations of various continents in different aspects are also present. The difference in cost between a private car and a public vehicle indicates which form of transportation should be chosen. The challenges linked with urban and rural Indian roadways are explored, as well as their respective solutions. In order to accomplish sustainable transportation, traffic density and driver conduct are also considered. This study emphasises that sustainability is not just achieved through the use of cleaner fuel or the modification of road materials, although these are vital. Road design, regulatory changes, psychological behaviour, and transit safety are also crucial.