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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.

Laser is emerging as a strong contender as an alternative ignition source for internal combustion (IC) engines. Short laser pulses of few nanoseconds duration delivered by a Q-switched laser are focused by a lens inside the engine cylinder containing combustible fuel-air mixture. If the peak intensity at the focal point exceeds threshold intensity level, breakdown of combustible gases occurs, which leads to plasma formation. If the energy of the spark generated by plasma is high enough, the mixture ignites. In this investigation, laser ignition (LI) was performed in a single cylinder engine at constant speed and wide open throttle conditions using CNG as fuel. Combustion behavior was recorded using a high speed data acquisition system. For laser ignition of the engine, a laser spark plug was designed and manufactured. Laser spark plug consists of combination of lenses and optical windows.

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.

Mixture formation in GDI engine is considered crucial in determining combustion and emissions characteristics, which mainly depend on fuel spray quality. However, spray characteristics change with variations in control parameters such as fuel injection parameters, fuel injection strategy, engine operating conditions, and fuel properties. Growing research interest in the use of methanol as an additive with gasoline has motivated the need for deeper investigations of spray characteristics of these fuels. Although, it can be noted that sufficient literature is available in the area of spray characterization under several independent influencing factors, however, comparative analysis of gasohol spray behavior under different ambient conditions is hardly studied.

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.

Alternative fuels, coupled with advanced engine technologies, are potential solutions to overcome energy crisis and environmental degradation challenges, that transport sector faces. Methanol has emerged as a potential candidate as an alternate fuel due to adequate availability of indigenous feedstocks, such as coal, biomass, and municipal solid waste (MSW). Policy makers of several countries are focusing on developing roadmap for methanol fueled vehicles, especially in developing countries like China and India. These countries have the largest two-wheeler market globally; therefore, methanol adaptability on 2-wheeler engine becomes important national priority. This study is aimed at feasibility assessment of methanol (M100) fueled two-wheeler engine using simulations. Present study was divided into four different phases.

Several experimental studies have been conducted for evaluating coefficient of friction and wear in simulated engine conditions using a piston ring segment and a liner piece rubbing against each other in reciprocating mode under load and lubricated conditions. In the present experimental investigation, a non-firing engine simulator has been developed in order to simulate engine conditions to a much closer extent. This machine can operate at similar linear speed, stroke, and load and can simulate almost similar engine operating conditions except firing pressures. This machine can also be used for comparing liners with different surface properties and the effects of surface texture on wear and oil consumption. One cylinder liner has been used for experimentation and the wear and surface properties behaviour were evaluated at several locations in the liner. Surface profile, roughness parameters are evaluated at several locations in the liner and at the top compression ring.

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.

Due to the increasingly stricter emission legislations and growing demand for lower fuel consumption, there have been significant efforts to improve combustion efficiency, while satisfying the emission requirements. Homogenous Charge Compression Ignition (HCCI) combustion offers significant efficiency improvements compared to conventional gasoline engines. However, due to the nature of HCCI, fully homogeneous charge HCCI combustion can be realized only in a limited operating range. Control of HCCI engines to obtain the desirable operation requires understanding of how different charge variables influence the cyclic variations in HCCI combustion. Under certain operating conditions, HCCI engines exhibit large cyclic variations in ignition timing. Cyclic variability ranging from stochastic to deterministic patterns can be observed. One important design goal for engine development is to minimize cyclic variability.

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.

Homogeneous Charge Compression Ignition (HCCI) offers great promise for excellent fuel economy and extremely low emissions of NOx and PM. HCCI combustion lacks direct control on the "start of combustion" such as spark timing in SI engines and fuel injection timing in CI engines. Auto ignition of a homogeneous mixture is very sensitive to operating conditions of the engine. Even small variations of the load can change the timing from "too early" to "too late" combustion. Thus a fast combustion phasing control is required since it sets the performance limitation of the load control. Crank angle position for 50% heat release is used as combustion phasing feedback parameter. In this study, a dual-fuel approach is used to control combustion in a HCCI engine. This approach involves controlling the combustion heat release rate by adjusting fuel reactivity according to the conditions inside the cylinder. Two different octane fuels (methanol and n-heptane) are used for the study.

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.

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.

Biodiesel made from Jatropha oil by transesterification process has viscosity and other important physical properties comparable to mineral diesel hence it can be used as an alternate fuel in conventional diesel engines. It is important to investigate the spray characteristics of biodiesel because emissions from the engines are dependent on fuel atomization process and resulting fuel-air mixing. This study focuses on the Jatropha biodiesel spray investigations using Phase Doppler Interferometry (PDI) for measurement of various microscopic spray parameters such as Sauter mean diameter (SMD) and spray droplet size and velocity distributions. The spray and engine experiments were carried out for Jatropha biodiesel (JB100) and their 20% blends (JB20) with mineral diesel as baseline. Fuel injection pressure during the spray experiments was maintained at 200 bars for all tests, quite similar to small horse power agricultural engines, and the fuel injection quantity was varied.

The rising concerns of emissions have put enormous strain on the automotive industry. Industry is, therefore looking for next-generation engines and advanced combustion technologies with ultra-low emissions and high efficiency. To achieve this, more insights into the combustion and pollutant formation processes in IC engines is required. Since conventional measures have not been insightful, in-situ measurement of combustion and pollution formation through optical diagnostics is being explored. Gaining full optical access into the diesel engine combustion chamber is a challenging task. The late-compression flow dynamics is not well understood due to limited access into the engine combustion chamber. These flow structures contribute immensely to fuel-air mixing and combustion. The objective of this study is to understand the role of combustion chamber design on vertical plane air-flow structures.

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.

Use of alternative fuels, and reduction of particulate and NOx emissions are major challenges for making diesel engines environmentally benign. Measures adopted for reducing gravimetric particulate emissions necessarily always do not reduce particulate number concentration, which is strongly related with adverse health effects. Current emission norms in some parts of the world limit particulate number concentration along with particulate mass. In this scenario, it becomes important to investigate effect of fuel injection parameters and fuel injection strategies such as pilot injections on particulate size-number distribution. A single cylinder research engine is used to evaluate the effect of different fuel injection strategies and injection timings (for pilot and main injections) on particulate size-number distribution and total particulate numbers.

IC engines are facing two major challenges in the 21st century namely threat of fossil fuel depletion and environmental concerns. HCCI engine is an attractive solution to meet stringent emission challenges due to its capability to simultaneously reduce NOx and PM. HCCI technology can be employed with different alternative fuels without significant modifications in the existing engines. In this study, HCCI combustion was investigated using B20 (20% v/v biodiesel with diesel). Investigations were carried out on a two cylinder engine, in which one cylinder was modified to operate in HCCI mode however the other cylinder operated in conventional CI combustion mode. A dedicated fuel vaporizer was used for homogeneous fuel-air mixture preparation. The experiments were performed at three different intake charge temperatures (160°C, 180°C and 200°C) and three different EGR ratios (0%, 10% and 20% EGR) at different engine loads.