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Technical Paper

Near Nozzle Flow and Atomization Characteristics of Biodiesel Fuels

2017-10-08
2017-01-2327
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.
Technical Paper

CI/PCCI Combustion Mode Switching of Diesohol Fuelled Production Engine

2017-03-28
2017-01-0738
Premixed charge compression ignition (PCCI) combustion is an advanced combustion technique, which has the potential to be operated by alternative fuels such as alcohols. PCCI combustion emits lower oxides of nitrogen (NOx) and particulate matter (PM) and results thermal efficiency similar to conventional compression ignition (CI) engines. Due to extremely high heat release rate (HRR), PCCI combustion cannot be used at higher engine loads, which make it difficult to be employed in production grade engines. This study focused on development of an advanced combustion engine, which can operate in both combustion modes such as CI combustion as well as PCCI combustion mode. This Hybrid combustion system was controlled by an open engine control unit (ECU), which varied the fuel injection parameters for mode switching between CI and PCCI combustion modes.
Technical Paper

An Experimental Investigation on Spray Characteristics of Waste Cooking Oil, Jatropha, and Karanja Biodiesels in a Constant Volume Combustion Chamber

2016-10-17
2016-01-2263
In this study, macroscopic spray characteristics of Waste cooking oil (WCO), Jatropha oil, Karanja oil based biodiesels and baseline diesel were compared under simulated engine operating condition in a constant volume spray chamber (CVSC). The high pressure and high temperature ambient conditions of a typical diesel engine were simulated in the CVSC by performing pre-ignition before the fuel injection. The spray imaging was conducted under absence of oxygen in order to prevent the fuels from igniting. The ambient pressure and temperature for non-evaporating condition were 3 MPa and 300 K. Meanwhile, the spray tests were performed under the ambient pressure and temperature of 4.17 MPa and 804 K under evaporating condition. The fuels were injected by a common-rail injection system with injection pressure of 80 MPa. High speed Mie-scattering technique was employed to visualize the evaporating sprays.
Technical Paper

Effects of Spray Droplet Size and Velocity Distributions on Emissions from a Single Cylinder Biofuel Engine

2016-04-05
2016-01-0994
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.
Technical Paper

Macroscopic and Microscopic Spray Characteristics of Diesel and Karanja Biodiesel Blends

2016-04-05
2016-01-0869
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).
Technical Paper

Microscopic and Macroscopic Spray Characteristics of GDI Injector Using Gasohol Fuels at Various Injection Pressures

2016-04-05
2016-01-0868
The development of advanced gasoline direct injection (GDI) injector requires in-depth investigations of macroscopic and microscopic spray characteristics. Over the years, GDI injectors have undergone exponential improvement to be able to deliver fuel at high injection pressure. High fuel injection pressure (FIP) leads to superior fuel atomization, and consequently superior fuel-air mixing. Present investigations aim to improve our fundamental knowledge of the furl-air mixture preparation mechanisms of different test fuels. Experiments were conducted to study spray breakup of GDI injector. This study focuses on the spray investigations using Phase Doppler Interferometry (PDI) for the measurement of various spray related studies such as determination of arithmetic mean diameter (AMD), sauter mean diameter (SMD) and spray droplet velocity distributions.
Technical Paper

Effect of Intake Charge Temperature and EGR on Biodiesel Fuelled HCCI Engine

2016-02-01
2016-28-0257
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.
Technical Paper

An Experimental Study of Microscopic Spray Characteristics of a GDI Injector Using Phase Doppler Interferometry

2016-02-01
2016-28-0006
Gasoline Direct Injection (GDI) engine is known for its higher power and higher thermal efficiency. Researchers are steadily determining and resolving the problems of fuel injection in a GDI engine. In order to meet the stringent emission norms such as PM and NOx emitted by a GDI engine, it is necessary to investigate the microscopic spray characteristics and fuel-air mixing process. This paper aims to share the fundamental knowledge of the interacting mixture preparation mechanisms at the wide range of fuel injection pressures. The investigations were carried out at five different fuel injection pressures viz: 40, 80, 120, 160, 200 bar, for 24 mg fuel per injection. A high speed CCD camera was used to determine the macroscopic spray characteristics of the GDI injector. It was found that spray penetration length increased with increasing fuel injection pressure. Phase Doppler Interferometry (PDI) was used to determine the droplet size and droplet velocity for different test fuels.
Journal Article

Tomographic Particle Image Velocimetry for Flow Analysis in a Single Cylinder Optical Engine

2015-04-14
2015-01-0599
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.
Technical Paper

Unregulated and Regulated Emissions from Biodiesel Fuelled CRDI SUV Engine

2015-04-14
2015-01-0889
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.
Technical Paper

Noise, Vibrations and Combustion Investigations of Preheated Jatropha Oil in a Single Cylinder Genset Engine

2015-04-14
2015-01-1668
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.
Journal Article

Particulate Morphology and Toxicity of an Alcohol Fuelled HCCI Engine

2014-04-15
2014-01-9076
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.
Technical Paper

Experimental Investigation of Close-Loop Control of HCCI Engine Using Dual Fuel Approach

2013-04-08
2013-01-1675
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.
Technical Paper

Comparative Evaluation of Turbochargers for High Horsepower Diesel-Electric Locomotives

2013-04-08
2013-01-0930
Indian Railways have a fleet of high-horsepower diesel-electric locomotives rated at 2310 kW. These high horsepower diesel-electric locomotives have evolved from original design of 1940 kW locomotives. Adoption of new design turbochargers was essential for this upgrading efforts and a series of new design turbochargers were evaluated on the engine test-bed before their use on the diesel locomotives. The objective was to increase engine power output, improve fuel efficiency and limit thermal loading. Test-bed evaluation of different turbochargers was carried out for comparing five different turbochargers. Each turbocharger had different size nozzle ring, diffuser, turbine blade assembly, impeller and inducer. The compressor maps of turbochargers were used to plot the engine load lines and to calculate surge margins. The tests involved measuring critical parameters for various combinations of engine speed and load for every turbocharger.
Technical Paper

Effect of Multiple Injections on Particulate Size-Number Distributions in a Common Rail Direct Injection Engine Fueled with Karanja Biodiesel Blends

2013-04-08
2013-01-1554
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.
Technical Paper

Macroscopic Spray Parameters of Karanja Oil and Blends: A Comparative Study

2012-01-09
2012-28-0028
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.
Technical Paper

Comparative Study of PM Mass and Chemical Composition from Diesel and Biodiesel Fuelled CRDI SUV Engine

2012-01-09
2012-28-0012
Adverse health effects of particulate matter (PM) originating from diesel engine exhaust are largely attributed to the complex chemical composition of the exhaust species. This study was set out to characterize particulate emissions from a Euro-III-compliant modern automotive common rail direct injection (CRDI) sports utility vehicle (SUV) diesel engine operated at different loads at rated engine speed (1800 rpm), employing diesel and 20% biodiesel blends (B20) produced from Karanja oil. This study is mainly divided into two main sections, first one includes the gravimetric analysis in order to assess the amount of Benzene Soluble Organic Fraction (BSOF) and trace metals using Inductively Coupled Plasma-Optical Emission Spectrometer (ICPOES). The second section includes real-time measurements for Organic Carbon (OC), Elemental Carbon (EC) and total particle-bound Polycyclic Aromatic Hydrocarbons (PAHs).
Journal Article

Effect of Start of Injection on the Particulate Emission from Methanol Fuelled HCCI Engine

2011-12-06
2011-01-2408
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.
Technical Paper

Experimental Investigation on Intake Air Temperature and Air-Fuel Ratio Dependence of Random and Deterministic Cyclic Variability in a Homogeneous Charge Compression Ignition Engine

2011-04-12
2011-01-1183
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.
Technical Paper

Oxidation Stability of Biodiesel Produced from Non-Edible Oils of African Origin

2011-04-12
2011-01-1202
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.
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