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Fourier Transform Infrared Spectroscopy Models to Predict Cetane Number of Different Biodiesels and Their Blends

Indian Institute of Technology-Kiran Raj Bukkarapu, Anand Krishnasamy
  • Technical Paper
  • 2020-01-0617
To be published on 2020-04-14 by SAE International in United States
The ignition quality of a fuel is described by its cetane number. Experimental methods used to determine cetane number employ Co-operative fuel research (CFR) engine and Ignition quality tester (IQT) which are expensive, have less repeatability and require skilled operation, and hence least preferred. There are many prediction models reported, which involve number of double bonds and number of carbon atoms whose determination is not direct. Using models that relate biodiesel composition to its cetane number is limited by the range of esters involved. Hence, a model to predict cetane number of biodiesels that addresses the limitations of the existing models, without ignoring the influence of factors such as degree of unsaturation and number of carbon atoms, is needed. Fourier transform infrared spectroscopy (FTIR) could be one such method. Five biodiesels with significant compositional variations were prepared from Camelina, Coconut, Karanja, Linseed and Palm oils, and blended in different volume proportions to arrive at 70 samples. The range of cetane number covered was from 42.2 to 65.4. Peak absorbance of different functional groups of these…
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A Holistic Approach to Develop a Common Rail Single Cylinder Diesel Engine for Bharat Stage VI Emission Legislation

Indian Institute of Technology-Vikraman Vellandi, A. Ramesh, Anand Krishnasamy
  • Technical Paper
  • 2020-01-1357
To be published on 2020-04-14 by SAE International in United States
The upcoming Bharat Stage VI (BS VI) emission legislation has put enormous pressure on the future of small diesel engines which are widely used in the Indian market. The present work investigates the emission reduction potential of a common rail direct injection single cylinder diesel engine by adopting a holistic approach of lowering the compression ratio, boosting the intake air and down-speeding the engine. Experimental investigations were conducted across the entire operating map of a mass-production, light-duty diesel engine to examine the benefits of the proposed approach and the results are quantified for the modified Indian drive cycle (MIDC). By reducing the compression ratio from 18:1 to 14:1, the oxides of nitrogen (NOx) and soot emissions are reduced by 40% and 75% respectively. However, a significant penalty in fuel economy, unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are observed with the reduced compression ratio. Intake air boosting using a mechanically driven supercharger could overcome the penalty in HC and CO emissions. However, the mechanical frictional losses of the supercharger resulted in a further penalty…
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Experimental Investigation of Multiple Injection Strategies on Combustion Stability, Performance and Emissions in a Methanol-Diesel Dual Fuel Non-Road Engine

Indian Institute of Technology-Kasinath Panda, A. Ramesh
  • Technical Paper
  • 2020-01-0308
To be published on 2020-04-14 by SAE International in United States
In this work methanol was port injected while diesel was injected using a common rail system in a single cylinder non-road CI engine. Experiments were conducted with single (SPI) and double (DPI - pilot and main) injection of the directly injected diesel at 75% load and at a constant speed of 1500 rpm. The effects of methanol to diesel energy share (MDES) and injection scheduling on combustion stability, efficiency and emissions were evaluated. Initially, in the SPI mode, the methanol to diesel Energy Share (MDES) was varied, while the injection timing of diesel was always fixed for best brake thermal efficiency (BTE). Increase in the MDES resulted in a reduction in NOx and smoke emissions because of the high latent heat of vaporization of methanol and the oxygen available. Enhanced premixed combustion led to a raise in brake thermal efficiency (BTE). Coefficient of variation of IMEP, peak pressure and BTE were deteriorated which limited the usable MDES to 43%. DPI of diesel i.e. early pilot for enhancing the reactivity of the charge along with main…
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Analysis of Combustion Noise in a Small Common-Rail Direct-Injection Diesel Engine at Different Engine Operating Conditions

Indian Institute of Technology-Hiresh Bundele, Mayank Mittal, Pramod Mehta
Kistler Instruments India Pvt., Ltd.-Ramesh KJ
  • Technical Paper
  • 2020-01-0419
To be published on 2020-04-14 by SAE International in United States
Stringent emission regulations on one hand and increasing demand for better fuel economy along with lower noise levels on the other hand require adoption of advanced common-rail direct-injection technologies in diesel engines. In the present work, a small 0.9-l, naturally aspirated, two-cylinder, common-rail direct-injection diesel engine is used for the analysis of combustion noise at different engine operating conditions. Experiments are conducted at different loads and engine speeds, incorporating both single and multiple (i.e. pilot and main) injections along with different injection timings. In the case of multiple injections, the influence of pilot injection quantity is also evaluated on the combustion noise while maintaining the same load. In-cylinder pressure was recorded with the resolution of 0.1 crank angle degree, and it was used for the quantitative analysis of noise assessed from the resulting cylinder pressure spectra, and sound pressure level. Results showed that the quantity of pilot injection has a considerable influence on combustion noise.
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Experimental Investigation of Combustion Stability and Particle Emission from CNG/Diesel RCCI Engine

Indian Institute of Technology-Mohit Raj Saxena, Rakesh Kumar Maurya
  • Technical Paper
  • 2020-01-0810
To be published on 2020-04-14 by SAE International in United States
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. Too advanced diesel injection results in a partial burn/misfire operating condition. The results indicate that the double diesel injection strategy has a relatively higher concentration of nucleation mode particles and it increases with advancing the diesel injection…
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Determination of Range of Fuel Premixing Ratio in Gasoline/Butanol-Diesel Dual-Fuel Engine for Lower Exhaust Emissions and Higher Efficiency

Indian Institute of Technology-Mohit Raj Saxena, Rakesh Kumar Maurya
  • Technical Paper
  • 2020-01-1128
To be published on 2020-04-14 by SAE International in United States
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. The influence of fuel PMR on combustion pressure, heat release rate, and coefficient of variance (COV) of indicated mean effective pressure (IMEP), brake thermal efficiency (BTE), combustion duration, and gaseous emissions…
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A Computational Study on the Effect of Injector Location on the Performance of a Small Spark-Ignition Engine Modified to Operate under the Direct-Injection Mode

Indian Institute of Technology-Jubin V. Jose, Hemant Thakur, Mayank Mittal, A. Ramesh
  • Technical Paper
  • 2020-01-0286
To be published on 2020-04-14 by SAE International in United States
In a direct-injection (DI) engine, charge motion and mixture preparation are among the most important factors deciding the performance and emissions. This work was focused on studying the effect of injector positioning on fuel-air mixture preparation and fuel impingement on in-cylinder surfaces during the homogeneous mode of operation in a naturally aspirated, small bore, 0.2 l, light-duty, air-cooled, four-stroke, spark-ignition engine modified to operate under the DI mode. A commercially available, six-hole, solenoid-operated injector was used. Two injector locations were identified based on the availability of the space on the cylinder head. One location yielded the spray-guided (SG) configuration, with one of the spray plumes targeted towards the spark plug. In the second location, the spray plumes were targeted towards the piston top in a wall-guided (WG) configuration so as to minimize the impingement of fuel on the liner. A CFD model was developed and validated using experimental data obtained on the same engine with the SG configuration. Computational results showed that both SG and WG configurations yielded similar levels of IMEP, however, in-cylinder turbulence…
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Microscopic and Macroscopic Spray Characteristics of Gasohols Using a Port Fuel Injection System

Indian Institute of Technology-Utkarsha Sonawane, Ankur Kalwar
  • Technical Paper
  • 2020-01-0324
To be published on 2020-04-14 by SAE International in United States
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. Macroscopic and microscopic spray characteristics of different gasohols such as M15 (15% methanol blended with 85% gasoline, v/v), M85 (85% methanol blended with 15% gasoline, v/v), M100 (100% methanol), and G100 (100% Gasoline) were experimentally investigated using a port fuel multi-hole solenoid injector. A Constant Volume Spray Chamber (CVSC) having glass windows was used for the experiments at a…
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Analysis of In-Cylinder Flow and Cycle-to-Cycle Flow Variations in a Small Spark-Ignition Engine at Different Throttle Openings

Indian Institute of Technology-Afaque Alam, Mayank Mittal
TVS Motor Co., Ltd.-V Lakshminarasimhan
  • Technical Paper
  • 2020-01-0793
To be published on 2020-04-14 by SAE International in United States
Flow variations from one cycle to the next significantly influence the mixture formation and combustion processes in engines. Therefore, it is important to understand the fluid motion and its cycle-to-cycle variations (CCVs) inside the engine cylinder. Researchers have generally investigated the cycle-to-cycle flow variations in moderate- to large-sized engines. In the present work, we have performed the flow measurement and analysis in a small spark-ignition engine. Experiments are conducted in an optically accessible, single-cylinder, port-fuel-injection engine with displacement volume of 110 cm3 at different throttle openings (i.e. 50% and WOT) using particle image velocimetry. Images are captured at different crank angle positions during both intake and compression strokes over a tumble measurement plane, bisecting the intake and exhaust valves and passing through the cylinder axis. The histograms of vorticity are used as a metric for the quantification of cycle-to-cycle flow variations. It is found that for wide-open (i.e. 100%) throttle, cycle-to-cycle variations first increased from 76 CAD (after TDC of intake) to a maximum value at about 118 CAD, and then decreased during the late…
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Performance of Isolated UAV Rotors at Low Reynolds Number

Indian Institute of Technology-Dhwanil Shukla
Georgia Institute of Technology-Yashvardhan Tomar, Narayanan Komerath
  • Technical Paper
  • 2020-01-0046
Published 2020-03-10 by SAE International in United States
Vertical takeoff and landing vehicle platforms with many small rotors are gaining importance for small UAVs as well as distributed electric propulsion for larger vehicles. To predict vehicle performance, it must be possible to gauge interaction effects. These rotors operate in the less-known regime of low Reynolds number, with different blade geometry. As a first step, two identical commercial UAV rotors from a flight test program are studied in isolation, experimentally and computationally. Load measurements were performed in Georgia Tech’s 2.13 m × 2.74 m wind tunnel. Simulations were done using the RotCFD solver which uses a Navier-Stokes wake computation along with rotor-disc loads calculation using low-Reynolds number blade section data. It is found that in hover, small rotors available in the market vary noticeably in performance at low rotor speeds, the data converging at higher RPM and Reynolds number. This is indicative of the high sensitivity of low-Re rotor flows to minor geometrical differences/imperfections in the rotors. It requires proper handling in computations. CFD results show a higher deviation from the experimental thrust data…
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