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Use of biodiesel from non-edible vegetable oil as an alternative fuel to mineral diesel is attractive economically and environmentally. Diesel engines emit several harmful gaseous emissions and some of them are regulated worldwide, while countless others are not regulated. These unregulated species are associated with severe health hazards. Karanja biodiesel is a popular alternate fuel in South Asia and various governments are considering its large-scale implementation. Therefore it is important to study the possible adverse impact of this new alternate fuel. In this study, unregulated and regulated emissions were measured at varying engine speeds (1500, 2500 and 3500 rpm) for various engine loads (0%, 20%, 40%, 60%, 80% and 100% rated load) using 20% Karanja biodiesel blend (KB20) and diesel in a 4-cylinder 2.2L common rail direct injection (CRDI) sports utility vehicle (SUV) engine.

Better understanding of flow phenomena inside the combustion chamber of a diesel engine and accurate measurement of flow parameters is necessary for engine optimization i.e. enhancing power output, fuel economy improvement and emissions control. Airflow structures developed inside the engine combustion chamber significantly influence the air-fuel mixing. In this study, in-cylinder air flow characteristics of a motored, four-valve diesel engine were investigated using time-resolved high-speed Tomographic Particle Imaging Velocimetry (PIV). Single cylinder optical engine provides full optical access of combustion chamber through a transparent cylinder and flat transparent piston top. Experiments were performed in different vertical planes at different engine speeds during the intake and compression stroke under motoring condition. For visualization of air flow pattern, graphite particles were used for flow seeding.

Increased environmental awareness and depletion of resources are driving industry to develop alternative fuels that are environmentally more acceptable. Fatty acids esters (biodiesel) are known to be good alternative fuels. Due to economic reasons, the use of cheap raw materials for biodiesel production is preferred. In this case, ricebran oil, non-edible grade is used. Base catalyzed transesterification of ricebran oil is investigated and process parameters for ricebran biodiesel production are optimized. Various properties like viscosity, density, flash point, calorific value of biodiesel thus prepared are characterized as per ASTM D6751 and found comparable to mineral diesel. Steady state engine dynamometer test at 1800 rpm has been carried out to evaluate the performance and emission characteristics of a medium duty transportation DI diesel engine. Emission tests with all the fuel blends have also been carried out using European 13 MODE test (ECE R49).

This experimental study was undertaken to investigate the use of vegetable oil derivatives to substitute mineral diesel fuel. Straight vegetable oils pose some problems like injector coking, carbon deposits etc., when used as a fuel in an engine. These problems are due to high viscosity, low volatility and polyunsaturated character of vegetable oils. Transesterified vegetable oil derivative called “biodiesel” appear to be most convenient way of utilizing vegetable oil as a substitute fuel in diesel engines. In present investigation, rice bran oil (non-edible) was transesterified to methyl ester and reaction conditions for transeterifcation process for rice bran oil were optimized. Various properties like viscosity, density, flash point of the biodiesel thus prepared are comparable to diesel and found to be in acceptable range as per ASTM norms (ASTM D6751). Experimental investigations were carried out on a four stroke, four cylinders, transportation DI diesel engine.

Environmental concerns have increased significantly world over in the past decade. Regulatory agencies are becoming increasingly concerned with particulate emissions as the health and environmental effects are getting understood better due to rapid development in instrumentation. Biodiesel is one of the most promising alternative diesel fuels, which is getting global acceptability among the automotive/ engine manufactures as well as users due to numerous benefits it offers over the conventional diesel. While much of literature is available on particulate emitted by diesel fuelled engine, little is known by particulate emissions from biodiesel fuelled compression ignition (CI) engine. This study concentrates on the characterization of particulate emissions from mineral diesel vis-à-vis biodiesel (B100) and its optimum blend (20%, B20) with mineral diesel.

Poor oxidation stability is the central problem associated with the commercial acceptance of the biodiesel. The EU standard (EN14214) specifies a minimum value of 6 h for biodiesel induction period at 110°C, measured with Rancimat instrument. Most of the freshly prepared biodiesel generally have lower induction periods than prescribed by the standards. Anti-oxidants are therefore added to enhance the oxidation/ storage stability of biodiesel. Oxidation is an exothermic process, and the reaction heat evolved makes it possible to use thermo gravimetric analysis (TGA). In the present study, the oxidation stability of methyl esters derived from Karanja oil and Neem oil, stabilized with anti-oxidant pyrogalol (PY) was studied by DSC. Onset temperature of freshly prepared Karanja biodiesel (KOME) and Neem biodiesel (NOME) was observed to be 148 and 153°C respectively. The stability increases with increasing anti-oxidant dosage.

Mono alkyl esters of long-chain fatty acids derived from renewable lipid feedstock, such as vegetable oils or animal fats, also known as biodiesel are well positioned to replace mineral diesel. The outstanding technical problem with biodiesel is that it is more susceptible to oxidation owing to its exposure to oxygen present in the air and high temperature. This happens mainly due to the presence of varying numbers of double bonds in the free fatty acid molecules. The chemical reactivity of esters can therefore be divided into oxidative and thermal instability, which can be determined by the amount and configuration of the olefinic unsaturation in the fatty acid chains. Many of the plant-derived fatty oils contain polyunsaturated fatty acids that are more prone to oxidation. Increasing production of biodiesel from vegetable oils (edible) places strain on food production, availability and price and leads to food versus fuel conflict.

Thermal loading of diesel engine pistons has increased dramatically in recent years due to applications of various advanced technologies to meet low emission and high power requirements. Control of piston temperatures by cooling of pistons has become one of the determining factors in a successful engine design. The pistons are cooled by oil jets fired at the underside from the crankcase. Any undesirable piston temperature rise may lead to engine seizure because of piston warping. However, if the temperature at the underside of the piston, where oil jet strikes the piston, is above the boiling point of the oil being used, it may contribute to the mist generation. This mist significantly contribute to the non-tail pipe emissions in the form of unburnt hydrocarbons (UBHC's), which has unfortunately not been looked into so seriously, as the current stress of all the automobile manufacturers is on meeting the tail pipe emission legislative limits.

Thermal loading of diesel engine pistons has increased dramatically in recent years due to applications of various technologies to meet low emission and high power requirements. Control of piston temperatures by cooling of these pistons has become one of the determining factors in a successful engine design. The pistons are cooled by oil jets fired at the underside from the crankcase. Any undesirable piston temperature rise may lead to engine seizure due to piston warping. However, if the temperature at the underside of the piston, where the oil jet strikes the piston, is above the boiling point of the oil being used, it may contribute to the mist generation. This mist may significantly contribute to the non-tail pipe emissions in the form of unburnt hydrocarbons (UBHC). The problem of non-tail pipe emissions has unfortunately not been looked into so seriously, as the current stress of all the automobile manufacturers is on meeting the tail -pipe emission legislative limits.

The world energy demand has witnessed uncertainties in two dimensions. The scarcity and depletion of conventional petroleum sources are causes of great concern worldwide. Combustion of fossil fuels has led to unprecedented rise in the global CO2 level, leading to global warming. Therefore, efforts are underway in several countries to search for suitable alternative fuels that are environment friendly. Vegetable oils of non-edible nature are such alternative fuels, which can form part of potential solution. Vegetable oils, due to their agricultural origin, are able to reduce CO2 emissions to the atmosphere along with import substitution of petroleum products In the present research, experiment were designed to study the effect of reducing Neem oil's high viscosity by increasing the fuel temperature and thereby its effect on combustion and emission characteristics of the engine.

High viscosity of vegetable oil causes ignition problems when used in compression ignition engines. There is a need to reduce the viscosity before using it as engine fuel. Preheating and pre-treating of vegetable oils using waste heat of exhaust gases is one of the techniques, which reduces the viscosity and makes it possible to use it as alternate fuel for some niche applications, without requiring major modifications in the engine hardware. Several applications such as decentralized power generation, agricultural engines, and water pumping engines, can use vegetable oils as an alternative fuel. In present investigation, performance, combustion, and emission characteristics of an engine using preheated 20% blend of Jatropha oil with mineral diesel (J20) has been evaluated at a constant speed (1500 rpm) in a single cylinder four stroke direct injection diesel engine.

Fuel atomization and air-fuel mixing processes play a dominant role on engine performance and emission characteristics in a direct injection compression ignition engine. Understanding of microscopic spray characteristics is essential to predict combustion phenomena. The present work investigated near nozzle flow and atomization characteristics of biodiesel fuels in a constant volume chamber. Waste cooking oil, Jatropha, and Karanja biodiesels were applied and the results were compared with those of conventional diesel fuel. The tested fuels were injected by a solenoid injector with a common-rail injection system. A high-speed camera with a long distance microscopic lens was utilized to capture the near nozzle flow. Meanwhile, Sauter mean diameter (SMD) was measured by a phase Doppler particle analyzer to compare atomization characteristics.

Fuel injection pressure (FIP) is one of the most important factors affecting diesel engine performance and particulate emissions. Higher FIP improves the fuel atomization, which results in lower soot formation due to superior fuel-air mixing. The objective of this spray study was to investigate macroscopic and microscopic spray parameters in FIP range of 500-1500 bar, using a solenoid injector for biodiesel blends (KB20 and KB40) and baseline mineral diesel. For these test fuels, effect of ambient pressure on macroscopic spray characteristics such as spray penetration, spray area and cone angle were investigated in a constant volume spray chamber (CVSC). Microscopic spray characteristics such as velocity distribution of droplets and spray droplet size distribution were measured in the CVSC at atmospheric pressure using Phase Doppler Interferometry (PDI).

Diesel engines are very efficient prime movers in their power range. Fuel is directly injected into the combustion chamber. Performance and emission characteristics of diesel engines are highly influenced by the fuel spray parameters and atomization of the injected fuel. As the emission regulations become stringent, it is very important to optimize the combustion in internal combustion engines for different fuels including alternative fuels. Spray visualization using optical techniques play a very important role to analyze macroscopic spray parameters and fuel atomization behavior. In the present experimental study, an important alternative CI engine fuel, Karanja oil and its blends with diesel have been investigated for their spray parameters and fuel atomization relative to mineral diesel. These parameters are different for the two fuels because of difference in the viscosity and density of the fuels.

Di-ethyl ether (DEE) belongs to the family of oxygenated fuels, which have been investigated as an alternative to conventional diesel. However, increasing the proportion of DEE in DEE-diesel blends changes its physicochemical properties. This work shows the non-evaporating and non-reacting spray characteristics of diesel, DEE20 (20% v/v DEE and 80% v/v diesel), and DEE40 (40% v/v DEE and 60% v/v diesel) were investigated. The effect of fuel injection pressure (FIP: 500 and 800 bar) on the spray morphology and droplet size distribution at different axial locations along the spray axis was done. FIP of 800 bar showed a reduction in Sauter mean diameter (SMD) of spray droplets with increasing axial distance due to improved spray atomisation because of the drag forces of the surrounding air on the fuel droplets. DEE20 showed a higher number of droplets having a smaller diameter than DEE40. DEE20 and DEE40 showed superior spray atomisation characteristics than diesel.

Fuel-air mixing is the main parameter, which affects formation of NOx and PM during CI combustion. Hence better understanding of air-flow characteristics inside the combustion chamber of a diesel engine became very important. In this study, in-cylinder air-flow characteristics of four-valve diesel engine were investigated using time-resolved high-speed tomographic Particle Imaging Velocimetry (PIV). For visualization of air-flow pattern, fine graphite particles were used for flow seeding. To investigate the effect of different operating parameters, experiments were performed at different engine speeds (1200 rpm and 1500 rpm), intake air temperatures (room temperature and 50°C) and intake port configurations (swirl port, tangential port and combined port). Intake air temperature was controlled by a closed loop temperature controller and intake ports were deactivated by using a customized aluminum gasket.

The development of more efficient and powerful internal combustion engines requires the use of new and advanced engine technologies. These advanced engine technologies and emission requirements for meeting stringent global emission norms have increased the power densities of engine leading to downsizing. In all these engines, cylinder head and liner are normally cooled but the piston is not cooled, making it susceptible to disintegration/ thermal damage. Material constraints restrict the increase in thermal loading of piston. High piston temperature rise may lead to engine seizure because of piston warping. So pistons are additionally cooled by oil jet impingement from the underside of the piston in heavy duty diesel engines. However, if the temperature at the underside of the piston, where the oil jet strikes the piston, is above the boiling point of the oil, it may contribute to the mist generation.

Biodiesel is mono alkyl ester derived from vegetable oils through transesterification reaction and can be used as an alternative to mineral diesel. In the present research, methyl ester of rice-bran oil (ROME) is produced through transesterification of rice-bran oil using methanol in presence of sodium hydroxide (NaOH) catalyst. Various properties like viscosity, density, flash point, calorific value of the biodiesel thus prepared are characterized and found comparable to diesel. On the basis of previous research for performance, emission and combustion characteristics, a 20% blend of ROME (B20) was selected as optimum biodiesel blend for endurance test. Endurance test of 100 hours was conducted on a medium duty direct injection transportation diesel engine. Tests were conducted under predetermined loading cycles in two phases: engine operating on mineral diesel and engine fuelled with 20% biodiesel blend.

The development of vehicles continues to be determined by increasingly stringent emissions standards including CO2 emissions and fuel consumption. To fulfill the simultaneous emission requirements for near zero pollutant and low CO2 levels, which are the challenges of future powertrains, many research studies are currently being carried out world over on new engine combustion process, such as Controlled Auto Ignition (CAI) for gasoline engines and Homogeneous Charge Compression Ignition (HCCI) for diesel engines. In HCCI combustion engine, ignition timing and combustion rates are dominated by physical and chemical properties of fuel/air/residual gas mixtures, boundary conditions including ambient temperature, pressure, and humidity and engine operating conditions such as load, speed etc.

This paper deals with the evaluation of steel cap pistons for up-gradation of diesel electric locomotives for Indian Railways. These engines are four stroke, medium speed compression ignition engines (CR 12.5: 1) with output of 121 kW per cylinder on series 1 and 167 kW per cylinder on series 2. The series 1 engine uses single piece aluminum pistons, with rating of 0.295 kW/cm2 of piston crown area. A higher version of the series 1 engine with higher fuel efficiency and improvement in lube oil consumption was developed. As part of this improvement program, a composite steel cap piston with forged aluminum skirt was used. The whole engine up-gradation kit including the higher capacity turbocharger, higher fuel delivery pressure fuel pump, modified cam shaft, larger after-cooler along with the steel cap piston were evaluated for performance.