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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.

In this study, the influence of fuel premixing ratio (PMR) on the performance, combustion, and emission characteristics of dual-fuel operation in the compression ignition (CI) engine have been investigated. For dual fuel operation in CI-engine, two fuels of different reactivity are utilized in the same combustion cycle. In this study, low reactivity fuels (gasoline/butanol) is injected into the intake manifold, and high reactivity fuel (diesel) is directly injected into the cylinder. To operate the conventional CI engine in dual-fuel mode, the intake manifold of the engine was modified and a solenoid based port fuel injector was installed. A separate port fuel injector controller was used for injecting the gasoline or butanol. Suitable instrumentation was used to measure in-cylinder pressure and exhaust gas emissions. Experiments were performed by maintaining the constant fuel energy at different fuel PMR for different engine loads at constant engine speed.

In the present work, the in-cylinder tumble/swirl flow and its effect on the homogeneity, turbulence, and combustion of methane are investigated in a canted valve engine using ANSYS. The study is focused on the impact of initial swirl and tumble on the charge preparation, turbulent kinetic energy, and combustion of methane. The flow simulation was performed in ANSYS using hybrid mesh for cold flow simulation to study the tumble/swirl flow variation. For combustion simulation, a 2D axisymmetric model was used with an initial swirl and tumble ratio for studying the effect on premixed combustion. The flow simulation was performed for suction and compression to see the variation in the swirl and tumble with crank position and engine speed. The combustion simulation was performed only for compression and power stroke to save the computation time. The results depict that the flow inside the cylinder plays a significant role in the preparation of a homogeneous charge.

Homogenous charge compression ignition (HCCI) combustion emerged as a potential technique for reducing automotive pollution. Controlling the combustion timing at different engine operating conditions is one of the major challenges for the commercial application of HCCI combustion engines. To control HCCI ignition timing, it is often necessary to know the characteristics of HCCI cyclic variations. In this study, cyclic combustion variations in an HCCI engine are analyzed. Combustion stability and cycle-to-cycle variations of HCCI combustion parameters were investigated on a modified four-stroke diesel engine. The experiments were conducted by varying intake air temperatures and relative air-fuel ratios at constant engine speed. In the steady-state engine operating condition, in-cylinder pressure signals of 2000 consecutive engine combustion cycles are acquired for each test condition.

This paper presents the experimental investigation of combustion stability and nano-particle emissions from the CNG-diesel RCCI engine. A modified automotive diesel engine is used to operate in RCCI combustion mode. An open ECU is used to control the low and high reactivity fuel injection events. The engine is tested for fixed engine speed and two different engine load conditions. The tests performed for various port-injected CNG masses and diesel injection timings, including single and double diesel injection strategy. Several consecutive engine cycles are recorded using in-cylinder combustion pressure measurement system. Statistical and return map techniques are used to investigate the combustion stability in the CNG-diesel RCCI engine. Differential mobility spectrometer is used for the measurement of particle number concentration and particle-size and number distribution. It is found that advanced diesel injection timing leading to higher cyclic combustion variations.

Depleting fossil-fuels and increasing harmful emissions by the combustion of fossil fuels in IC engine is a matter of great concern. It is necessary to explore solutions complying with the prevailing emission norms in different sectors. Methanol has the potential amongst all primary alcohols for widespread use in transport sector due to its clean-burning, high octane rating, sources of production like high ash coal, and biomass. The addition of methanol to gasoline can significantly reduce engine-out emissions. Gasoline-Methanol blends (Gasohols) can be used to reduce dependence of the transport sector on fossil fuels. This study deals with investigation of spray characteristics of methanol-gasoline blends as it affects engine performance and emissions characteristics to a great extent.

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.

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.

New combustion concepts developed in internal combustion engines such as homogeneous charge compression ignition (HCCI) have attracted serious attention due to the possibilities to simultaneously achieve higher efficiency and lower emissions, which will impact the environment positively. The HCCI combustion concept has potential of ultra-low NOX and particulate matter (PM) emission in comparison to a conventional gasoline or a diesel engine. Environmental Legislation Agencies are becoming increasingly concerned with particulate emissions from engines because the health and environmental effects of particulates emitted are now known and can be measured by sophisticated instruments. Particulate emissions from HCCI engines have been usually considered negligible, and the measurement of mass emission of PM from HCCI combustion systems shows their negligible contribution to PM mass. However some recent studies suggest that PM emissions from HCCI engines cannot be neglected.

Homogeneous charge compression ignition (HCCI) engines are attracting attention as next-generation internal combustion engines mainly because of very low NOx and PM emission potential and excellent thermal efficiency. Particulate emissions from HCCI engines have been usually considered negligible however recent studies suggest that PM number emissions from HCCI engines cannot be neglected. This study is therefore conducted on a modified four cylinder diesel engine to investigate this aspect of HCCI technology. One cylinder of the engine is modified to operate in HCCI mode for the experiments and port fuel injection technique is used for preparing homogenous charge in this cylinder. Experiments are conducted at 1200 and 2400 rpm engine speeds using gasoline, ethanol, methanol and butanol fuels. A partial flow dilution tunnel was employed to measure the mass of the particulates emitted on a pre-conditioned filter paper.

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.

Vegetable oils are produced from numerous oil seed crops. While all vegetable oils have high energy content, most require some processing to assure safe use in internal combustion engines. Some of these oils already have been evaluated as substitutes for diesel fuels. However, several operational and durability problems of using straight vegetable oils in diesel engines are reported in the literature, caused by of their higher viscosity and low volatility compared to mineral diesel. In the present research, experiments were designed to study the effect of reducing Jatropha oil's viscosity by blending it with mineral diesel and thereby eliminating the effect of high viscosity and poor volatility on combustion characteristics of the engine. Experimental investigations have been carried out to examine the combustion characteristics of an indirect injection transportation diesel engine running with diesel, and jatropha oil blends with diesel.

Biodiesel (fatty acid methyl ester) is a non-toxic and biodegradable alternative fuel that is obtained from renewable sources. A major hurdle in the commercialization of biodiesel from virgin oil, in comparison to petroleum-based diesel, is its cost of production, primarily the raw material cost. Used cooking oils or waste cooking oils are economical sources for biodiesel production, which can help in commercialization of biodiesel. However, the products formed during cooking/frying (such as free fatty acids and various polymerized triglycerides) affect the transesterification reaction and the biodiesel properties. In present experimental investigations, wastecooking oil obtained from restaurant was used to produce biodiesel through transesterification process and the chemical kinetics of biodiesel production was studied. Biodiesel was blended with petroleum diesel in different proportions.

The interface between the piston rings and cylinder liner play an important role in total frictional losses and mechanical wear of internal combustion engine and is increasingly coming under scrutiny as legislated particulate emission standards are getting more and more stringent. The capacitance method is used for measurement of minimum oil film thickness between piston ring and liner interface. Measurement of capacitance formed between the piston ring and a probe mounted flush in the liner provides an accurate means of determining the oil film thickness provided that the region between the probe and liner is flooded with oil and dielectric constant of the oil is known. This paper presents detailed design and measurement of lubricating oil film thickness using capacitive micro sensor in a non-firing engine simulator. Lubricating oil film thickness was found to vary between 0.2μm to 8μm in the non firing engine simulator.

Biodiesel is being explored as a sustainable renewable fuel for vehicles in India due to mounting foreign exchange expenditure to import crude petroleum. Significant amount of research and development work is being undertaken in India to investigate various aspects of biodiesel utilisation in different types of engines. This study is an effort to jointly investigate the use of biodiesel (B100) in an unmodified BS-III compliant sports utility vehicle (SUV) by a consortium of academia (IIT Kanpur) and Industry (M&M) to realistically assess whether biodiesel is compatible with modern engine technology vehicles. Two identical vehicles were operated in tandem using biodiesel (B100) and mineral diesel (B00) respectively for 30,000 kilometers in field conditions. The lubricating oil samples were collected and detailed analysis for assessing the comparative effect of new fuel (B100) vis-à-vis mineral diesel was carried out.

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).

Due to the demands of the market to increase efficiency and power density of large MW size gas engines, existing ignition schemes are gradually reaching their limits. These limitations initially triggered the development of laser ignition as an effective alternative, first only for gas engines and now for a much wider range of internal combustion engines revealing a number of immediate advantages like no electrode erosion or flame kernel quenching. Within this broad range investigation, laser plasmas were generated by ns Nd-YAG laser pulses and characterized by emission and Schlieren diagnostic methods. High-pressure chamber experiments with lean hydrogen- air mixtures were successfully performed and allowed the determination of essential parameters like minimum pulse energies at different ignition pressures and temperatures as well as at variable fuel air compositions. In this way, relevant parameters were acquired allowing estimation/ development of future laser ignition systems.

The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from vegetable oils present promising “greener” substitutes for fossil fuels. Vegetable oils due to their agricultural origin are able to reduce net CO2 emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported, which are because of their higher viscosity and low volatility compared to mineral diesel. In the present research, experiments were designed to study the effect of reducing Jatropha oil's viscosity by blending with mineral diesel, thereby eliminating its effect on combustion characteristics of the engine. In the present experimental research, vegetable oil (Jatropha Curcus) was used as substitute fuel.

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.

Vegetable oils have energy content suitable to be used as compression ignition (CI) engine fuel. However, several operational and durability problems of using straight vegetable oils in CI engines are reported in the literature, which are primarily caused by their higher viscosity and low volatility compared to mineral diesel. The viscosity can be brought in acceptable range by (i) chemical process of transesterification, (ii) blending of oil with mineral diesel or (iii) by heating the vegetable oil using exhaust gas waste heat. Reduction of viscosity by blending or exhaust gas heating saves the chemical processing cost of transesterification. Present experimental investigations were carried out for evaluating combustion, performance and emission behavior of Jatropha oil blends in unheated conditions in a direct injection CI engine at different load and constant engine speed (1500 rpm).