N. V. Deshpande

3D CFD Simulations of Hydrogen Fuelled Spark Ignition Engine

By supporting hydrogen as an alternative fuel to the conventional fuel i.e. gasoline, new era of renewable and carbon neutral energy resources can be introduced. Hence, development of hydrogen fuelled internal combustion engine for improved power density and less emission of NOx has become today’s need and researchers are continuously extending their efforts in the improvement of hydrogen fuelled internal combustion engine. In this work, three dimensional CFD simulations were performed using CFD code (AVL FIRE) for premixed combustion of hydrogen. The simplified 3D geometry of engine with single valve i.e. inlet valve was considered for the simulation. Various combustion models for spark ignition for hydrogen i.e. Eddy Breakup model, Turbulent Flame Speed Closure Combustion Model, Coherent Flame model, Probability Density Function model were tested and validated with available simulation results. Results obtained in simulation indicate that the properties of hydrogen i.e. high flame speed, wide flammability limit, and high ignition temperature are among the main influencing factors for hydrogen combustion being different than that of gasoline. Different parameters i.e. spark advance angle (TDC to 40° before TDC in the step of 5°), rotational speed (1200 to 3000 rpm in the step of 300 rpm), equivalence ratio (0.5 to 1.2 in the step of 0.1), and compression ratio (8, 9 and 10) were used to simulate the combustion of hydrogen in spark ignition engine and to investigate their effects on the engine performance, which is in terms of pressure distribution, temperature distribution, species mass fraction, reaction progress variable and rate of heat release for complete cycle. The results of power output for hydrogen were also compared with that of gasoline. It has been observed that power output for hydrogen is almost 12–15% less than that of gasoline.Copyright

Ceramic Composite Diesel Filter Trap

Diesel engine is a major source of power of the future but the major growing concern is the emissions of nitrogen oxides and diesel particulates. This work deals with the particulate emission control of diesel engine exhaust using ceramic filter. The selection of CFT with suitable size, geometry, cell density, wall thickness and microstructure becomes most important. In order to achieve required particulate matter emission limits and lower backpressure, optimization of porosity, pore size distribution, mean pore size and pore connectivity in CFT is crucial. CFT are developed and tested on the basis of porosity, diameter and length of CFT with necessary recommended trials. Further experiments were carried out to understand the effect of porosity, diameter and length of CFT on the back pressure, rate of back pressure rise, filtration efficiency and break power of diesel engine. The investigation of the research work provides adequate relevant information about the development of ceramic type ceramic filter trap (CFT) with naturally available material and effect of CFT on particulate matter concentration and on engine performance. Use of CFT reduced smoke drastically without increasing back pressure beyond tolerable back pressure limit. Performance of developed CFT was compared with established CFT and matches with it. Cost of developed CFT is the distinct advantage which will promote cottage industries in undeveloped nations, and provide rural employment.Copyright

Experimental Investigations on the Effect of Long Term Biodiesel Usage on Thermal Decomposition of CI Engine Crankcase Oil

The gradual depletion of world petroleum reserves, increases in prices of petroleum based fuels and environmental pollution due to exhaust emissions have encouraged studies to search for alternative fuels. Biodiesel is an alternative diesel fuel consisting of alkyl monoesters of fatty acids derived from vegetable oils. It has been the focus of considerable amount of recent research because it is renewable and reduces the emission of some pollutants. The desirability of developing biodiesel from different tree borne oil seeds and decreasing the dependency on petroleum based fuels has been discussed by many over the last few decades. However some of the important issues like compatibility of biodiesel with the crankcase lubricating oil, thermal stability of lubricating oil with biodiesel usage, changes in physical and chemical properties of lubricating oil with biodiesel etc. have not been sufficiently investigated. This needs to be addressed in order to ensure the long term acceptability of biodiesel in an existing family of diesel engines. In the present work these issues have been addressed. For this purpose engine endurance tests were conducted on CI engines. Two new single cylinder four stroke CI engines were operated for 512 hours each for diesel and 100% biodiesel fuel. The endurance tests were conducted as per BIS 10000 part IX norms. Biodiesel from Jatropha oil was prepared in-house using transesterification process. The sample of lubricating oil was collected through a one way valve connected to the crankcase sump after every 128 hours intervals. Thermograviometric analysis (TGA) was used to evaluate the thermal stability of lubricating oil samples obtained from both the engines. The thermal decomposition of lubricating oil samples were measured as a function of various reaction parameters such as temperature, time and heating rates. This TGA test involves a weight change as the oil was heated. The weight loss data of the sample was logged using the in situ computer. Early decomposition of biodiesel fueled engine lubricating oil was observed as compared to diesel fueled engine lubricating oil. The changes in viscosity of lubricating oil were also monitored during the endurance test and discussed in detail. A higher level of crank case dilution was observed in case of biodiesel as compared to diesel.Copyright

Experimental Investigations of Porosity, Diameter and Length of Ceramic Diesel Particulate Filter (DPF)

Diesel engine is the most efficient power plant among all known types of internal combustion engines. The Diesel engine is a major candidate to become the power plant of the future. Environmental benefits of Diesel such as low green house gas emissions are balanced by growing concern with emission of Nitrogen oxide (NOx) and Diesel Particulates (PM). The concern over Diesel particulate has increased in recent year because of health concerns. The objective of this research work is to identify the possibility of development of foam type diesel particulate filters (DPF) with indigenous ceramic materials which are easily available and cheaper. While developing the foam type diesel particulate filters, the main aim is to develop required porous structure for DPF with substantial strength, with low back pressure to minimize loss of engine performance, and with high trapping efficiency to reduce the particulate matter. The objective of this research work is also to investigate the effect of new developed filters without any regeneration arrangement and without any control or monitoring system, on the reduction of dry particulate matter and on the performance of diesel engine in terms of parameters like smoke density, back pressure, brake thermal efficiency and brake power. Use of DPF reduces smoke density with back pressure in acceptable limit. Parameters like brake power loss, increase in brake specific fuel consumption and decrease in brake thermal efficiency are caused by increased engine back pressure created by installation of the DPF system. This power penalty is within permissible limits, but can be further reduced by incorporating a regeneration system.Copyright

Parametric Optimization of WEDM of High Chromium High Carbon Die Steel Using ANN

In this research, single pass cutting of HCHC (High Chromium High Carbon) die steel AISI D3 Grade has been used where material removal rate (MRR) and surface roughness (SR) are of primary importance. In general, achieving a high level cutting speed with a better surface finish is extremely difficult task because in wire cut electric discharge machining (WEDM), no particular parametric combination is expected to yield simultaneously in the best MRR and the best SR. Hence it can be considered as multi objective optimization problem. This research presents an attempt at multi objective optimization of the process parametric combinations by modeling the process using artificial neural network (ANN). A feed forward back propagation neural network based on matrix experimental design is developed to model the WEDM process. Based on the developed model, different response parameters are calculated for various input parameter setting. Finally they are compared to find out optimal combination of machining parameter setting. Electronica make EZEECUT PLUS model has been used for experimentation and a methodology has been suggested to determine the optimal combination of control parameters in WEDM. Research findings in the area of machining HCHC die steel through WEDM process will open up a new horizon and will certainly solve various challenging problems faced by the engineers and die makers in the field of modern manufacturing industry.Copyright

Jatropha and Pongamia Straight Vegetable Oils as an Alternative to Diesel as a Fuel

With the fossil fuel depleting very fast, researchers have concentrated on developing new agro-based alternative fuels, which will provide sustainable solution to the energy crisis. Presently, bio-diesels, which are obtained from trans-esterification of straight vegetable oil (SVO), are being used along with diesel in blends. The transesterification process, which is a costly, time consuming and oil quality dependent process is eliminated in the present study. The straight vegetable oils, namely, Jatropha and Pongamia have been analyzed in details. The trial was conducted on a 4-stroke, single cylinder diesel engine, having compression ratio 17.5:1. The experiments were carried out for fuel consumption and emission levels at various loads and without any engine modifications. The results obtained were comparable to and better than diesel. The CO and NOx emission was found less for Jatropha as well as for Pongamia. The specific fuel consumption (SFC) was found to be low for both Jatropha and Pongamia oil at moderate loads. The brake thermal efficiency was also found to be better for both Jatropha and Pongamia oil as compared to diesel© 2005 ASME

Use of Ethanol Based Oxygenates for Smoke Reduction in C.I. Engines

Diesel Engines have better fuel economy compared to gasoline engines. Society is now aware of various harmful effects of pollution and various researchers are trying to use fuel reformulation method to meet the forthcoming stringent air pollution norms for the diesel engines. This paper presents an experimental investigation on use of three different low price ethanol based oxygenate-diesel blends (oxygenate 4, 8 and 12% in blend) as an oxygen enriched fuel in diesel engine and its effect on brake thermal efficiency, smoke density and emissions of CO, HC, NOx etc is studied. It was observed that there is substantial reduction in the smoke density of exhaust gases and the observed reduction was found proportional to the mass of oxygen present in the blend. Marginal increase in NOx and brake thermal efficiency was observed and there was no significant change in the brake power of the engine.Copyright