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Journal Article

Investigations on Spark and Corona Ignition of Oxymethylene Ether-1 and Dimethyl Carbonate Blends with Gasoline by High-Speed Evaluation of OH* Chemiluminescence

2018-03-01
Abstract Bio-fuels of the 2nd generation constitute a key approach to tackle both Greenhouse Gas (GHG) and air quality challenges associated with combustion emissions of the transport sector. Since these fuels are obtained of residual materials of the agricultural industry, well-to-tank CO2 emissions can be significantly lowered by a closed-cycle of formation and absorption of CO2. Furthermore, studies of bio-fuels have shown reduced formation of particulate matter on account of the fuels’ high oxygen content therefore addressing air quality issues. However, due to the high oxygen content and other physical parameters these fuels are expected to exhibit different ignition behaviour. Moreover, the question is whether there is a positive superimposition of the fuels ignition behaviour with the benefits of an alternative ignition system, such as a corona ignition.
Journal Article

Soot Observations and Exhaust Soot Comparisons from Ethanol-Blended and Methanol-Blended Gasoline Combustion in a Direct-Injected Engine

2018-05-07
Abstract Particulate formation was studied under homogeneous-intent stoichiometric operating conditions when ethanol-blended (E10) or methanol-blended (M20) gasoline fuel was injected during intake stroke of a 4-stroke direct-injected engine. The engine was tested at wide open throttle under naturally aspirated conditions for a speed-load of 1500 rev/min and 9.8 bar indicated mean effective pressure. In-cylinder soot observations and exhaust soot measurements were completed for different fuel rail pressures, injection timings, coolant and piston temperatures of the optical engine. Fuel delivery settings were tested with both single and split injections during intake stroke. The target piston temperature of the optical engine was attained using pre-determined number of methane port fuel injection firing cycles. Overall, the in-cylinder soot observations correlated well with the engine-out soot measurements. A warmer cylinder head favored soot reduction for both fuels.
Journal Article

Corrosion Behavior of Automotive Materials with Biodiesel: A Different Approach

2018-05-07
Abstract The issue of material compatibility of biodiesel has been discussed by few researchers but the reported corrosion rates were alarmingly high. This study addresses the corrosion issue of biodiesel with automotive materials with a different but systematic approach following SAE J1747 standard. In earlier studies while conducting material compatibility studies with biodiesel, mention of any specific standard/s has not been generally observed. Earlier studies were conducted by storing the samples for a long time without any change of fuel. However in actual automotive application, change of fuel is always on a periodic basis due to consumption of fuel and the SAE standard recommends for the same. This difference has a significant effect on the material compatibility as this periodic change does not result in making the fuel particularly biodiesel more acidic which is otherwise when stored for a long time during the test period.
Journal Article

Compatibility Assessment of Fuel System Thermoplastics with Bio-Blendstock Fuel Candidates Using Hansen Solubility Analysis

2018-03-01
Abstract The compatibility of key fuel system infrastructure plastics with 39 bio-blendstock fuel candidates was examined using Hansen solubility analysis. Fuel types included multiple alcohols, esters, ethers, ketones, alkenes and one alkane. These compounds were evaluated as neat molecules and as blends with the gasoline surrogate, dodecane and a mix of dodecane and 10% ethanol (E10D). The plastics included polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyoxymethylene (POM), polybutylene terephthalate (PBT), polypropylene (PP), high density polyethylene (HDPE), along with several nylon grades. These materials have been rigorously studied with other fuel types, and their volume change results were found to correspond well with their predicted solubility levels.
Journal Article

The Impacts of Pd in BEA Zeolite on Decreasing Cold-Start NMOG Emission of an E85 Fuel Vehicle

2018-10-25
Abstract In the development of hydrocarbon (HC) traps for E85 fuel vehicle emission control, the addition of palladium (Pd) to BEA zeolite was studied for trapping and decreasing cold-start ethanol emissions. BEA zeolite after a laboratory aging at 750°C for 25 hours released nearly all of the trapped ethanol as unconverted ethanol at low temperature, and some ethene was released at a higher temperature by a dehydration reaction. The addition of Pd to BEA zeolite showed a decrease in the release of unconverted ethanol emissions even after the lab aging. The release of methane (CH4), acetaldehyde (CH3CHO), carbon monoxide (CO), and CO2 from Pd-BEA zeolite during desorption (temperature programmed desorption (TPD)) demonstrated that multiple ethanol reaction mechanisms were involved including dehydrogenation and decomposition reactions.
Journal Article

Limitations of Monoolein in Simulating Water-in-Fuel Characteristics of EN590 Diesel Containing Biodiesel in Water Separation Testing

2018-10-18
Abstract In modern diesel fuel a proportion of biodiesel is blended with petro-diesel to reduce environmental impacts. However, it can adversely affect the operation of nonwoven coalescing filter media when separating emulsified water from diesel fuel. This can be due to factors such as increasing water content in the fuel, a reduction in interfacial tension (IFT) between the water and diesel, the formation of more stable emulsions, and the generation of smaller water droplets. Standard water/diesel separation test methods such as SAE J1488 and ISO 16332 use monoolein, a universal surface-active agent, to simulate the effects of biodiesel on the fuel properties as part of water separation efficiency studies. However, the extent to which diesel/monoolein and diesel/biodiesel blends are comparable needs to be elucidated if the underlying mechanisms affecting coalescence of very small water droplets in diesel fuel with a low IFT are to be understood.
Journal Article

Disc Pad Physical Properties vs. Porosity: The Question of Compressibility as an Intrinsic Physical Property

2017-09-17
Abstract Disc pad physical properties are believed to be important in controlling brake friction, wear and squeal. Thus these properties are carefully measured during and after manufacturing for quality assurance. For a given formulation, disc pad porosity is reported to affect friction, wear and squeal. This investigation was undertaken to find out how porosity changes affect pad natural frequencies, dynamic modulus, hardness and compressibility for a low-copper formulation and a copper-free formulation, both without underlayer, without scorching and without noise shims. Pad natural frequencies, modulus and hardness all continuously decrease with increasing porosity. When pad compressibility is measured by compressing several times as recommended and practiced, the pad surface hardness is found to increase while pad natural frequencies and modulus remain essentially unchanged.
Journal Article

Erosion Wear Response of Linz-Donawitz Slag Coatings: Parametric Appraisal and Prediction Using Imperialist Competitive Algorithm and Neural Computation

2019-03-14
Abstract Slag, generated from basic oxygen furnace (BOF) or Linz-Donawitz (LD) converter, is one of the recyclable wastes in an integrated steel plant. The present work aims at utilization of waste LD slag to develop surface coatings by plasma spraying technique. This study reveals that LD slag can be gainfully used as a cost-effective wear-resistant coating material. A prediction model based on an artificial neural network (ANN) is also proposed to predict the erosion performance of these coatings. The 2.27% error shows that ANN successfully predicts the erosion wear rate of the coatings both within and beyond the experimental domain. In addition to it, a novel optimization algorithm called imperialist competitive algorithm (ICA) is used to obtain minimum erosion wear rate of 12.12 mg/kg.
Journal Article

Studies on Friction Mechanism of NAO Brake-Pads Containing Potassium Titanate Powder as a Theme Ingredient

2017-09-17
Abstract Potassium titanate (KT) fibers/whiskers are used as a functional filler for partial replacement of asbestos in NAO friction materials (FMs). Based on little information reported in open literature; its exact role is not well defined since some papers claim it as the booster for resistance to fade (FR), or wear (WR) and sometimes as damper for friction fluctuations. Interestingly, KT fibers and whiskers (but not powder) are proved as carcinogens by the International Agency for Research on Cancer (IARC). However, hardly any efforts are reported on exploration of influence of KT powder and its optimum amount in NAO FMs (realistic composites) in the literature. Hence a series of five realistic multi-ingredient compositions in the form of brake-pads with similar parent composition but varying in the content of KT powder from 0 to 15 wt% (in the steps of 3) were developed. These composites were characterized for physical, mechanical, chemical and tribological performance.
Journal Article

Experimental Investigation of Ethanol-Diesel-Butanol Blends in a Compression Ignition Engine by Modifying the Operating Parameters

2018-10-31
Abstract The rapid utilization of fossil fuels has triggered the finding of alternative renewable fuel that replaces or reduces the consumption by alternative fuels for fueling compression ignition (CI) engines. One such renewable fuel is ethanol which can be manufactured from biomass. The present study details the utilization of an optimum amount of ethanol in CI engine by modifying the operating parameters. It was already published in the previous paper that 45% ethanol can be utilized along with diesel using 10% butanol as cosolvent. This fuel is also meeting the minimum requirement with respect to properties as per ASTM standards. This experimental study was performed to investigate the influence of modifying the engine operating parameters on the performance, combustion, and emission parameters fueled with the blend containing 45% ethanol under various load conditions.
Journal Article

Experimental Study of Ignition Delay, Combustion, and NO Emission Characteristics of Hydrogenated Vegetable Oil

2019-02-01
Abstract In this article, a comparative study of hydrogenated vegetable oil (HVO) and Diesel was performed in two constant volume combustion rigs and an optical accessible compression-ignited chamber (OACIC). Ignition, combustion, and nitric oxide (NO) emissions were studied under constant ambient gas density of 16.4 kg/m3, 21% vol oxygen concentration, and two different injection pressures of 800 and 1000 bar. Emission of NO was measured only in the OACIC, while a line-of-sight soot temperature distribution by applying two-color pyrometry was investigated in both setups. In general, the HVO as alternative fuel showed shorter ignition delay and less NO emission than Diesel for both injection pressures. Due to difference in the molecular structure, soot temperature of biofuel flames had narrower temperature spectrum than conventional fuel. Moreover, this study reveals the significance of wall-jet interaction for utilization of the biofuel.
Journal Article

Rapid Methodology to Simultaneous Quantification of Differ Antioxidants in Biodiesel Using Infrared Spectrometry and Multivariate Calibration

2019-03-21
Abstract The aim of this work is to quantify three different antioxidants in biodiesel - Santoflex, baynox, and tocopherol-using Middle Infrared (MIR) spectroscopy and chemometrics. For the construction of the models, 28 samples containing an antioxidant in the range of 0.1 to 500 mg/kg in biodiesel were used. We developed three models based on PLS 1 multivariate calibration method to quantify each of the three antioxidants separately and a model based on PLS 2 method to quantify simultaneously all the antioxidants. All models were compared to the values of root mean square error of calibration (RMSEC) and validation (RMSEP). For the baynox, santoflex, and tocopherol antioxidants quantification using PLS 1, the values of RMSEC and RMSEP were 37.2, 18.8, 9.0 mg/kg, and 26.7, 21.1, 68.6 mg/kg, respectively.
Journal Article

Investigation into the Tribological Properties of Biodiesel-Diesel Fuel Blends Under the Run-In Period Conditions

2019-06-25
Abstract Lubricity is a very important issue for diesel fuel injectors and pumps (of an engine) that are lubricated by the fuel itself. Biodiesel as an alternative fuel has a number of technical advantages compared to conventional diesel. It is required to perform more research about the tribological behavior of biodiesel blends under run-in period conditions at different rotational speeds. Friction characteristics of biodiesel (mixture of sunflower and soybean methyl ester) were studied by using a four-ball wear testing machine. Results indicated that the friction was reduced with the increase in rotational speed under the run-in period conditions. Moreover, the results showed that the friction coefficient decreases at rotational speeds of 600 and 900 rpm as the proportion of biodiesel increases in the fuel blend.
Journal Article

A Multiscale Cylinder Bore Honing Pattern Lubrication Model for Improved Engine Friction

2019-07-02
Abstract Three-dimensional patterns representing crosshatched plateau-honed cylinder bores based on two-dimensional Fast Fourier Transform (FFT) of measured surfaces were generated and used to calculate pressure flow, shear-driven flow, and shear stress factors. Later, the flow and shear stress factors obtained by numerical simulations for various surface patterns were used to calculate lubricant film thickness and friction force between piston ring and cylinder bore contact in typical diesel engine conditions using a mixed lubrication model. The effects of various crosshatch honing angles, such as 30°, 45°, and 60°, and texture heights on engine friction losses, wear, and oil consumption were discussed in detail. It is observed from numerical results that lower lubricant film thickness values are generated with higher honing angles, particularly in mixed lubrication regime where lubricant film thickness is close to the roughness level, mainly due to lower resistance to pressure flow.
Journal Article

Impact of Dynamic Characteristics of Wheel-Rail Coupling on Rail Corrugation

2019-07-02
Abstract To gain a better understanding of the characteristics of corrugation, including the development and propagation of corrugation, and impact of vehicle and track dynamics, a computational model was established, taking into account the nonlinearity of vehicle-track coupling. The model assumes a fixed train speed of 300 km/h and accounts for vertical interaction force components and rail wear effect. Site measurements were used to validate the numerical model. Computational results show that (1) Wheel polygonalisation corresponding to excitation frequency of 545-572 Hz was mainly attributed to track irregularity and uneven stiffness of under-rail supports, which in turn leads to vibration modes of the bogie and axle system in the frequency range of 500-600 Hz, aggregating wheel wear. (2) The peak response frequency of rail of the non-ballasted track coincides with the excitation frequency of wheel-rail coupling; the resonance results in larger wear amplitude of the rail.
Journal Article

Modelling and Numerical Simulation of Dual Fuel Lean Flames Using Local Burning Velocity and Critical Chemical Timescale

2019-07-02
Abstract Addition of hydrogen to hydrocarbons in premixed turbulent combustion is of technological interest due to their increased reactivity, flame stability and extended lean extinction limits. However, such flames are a challenge to reaction modelling, especially as the strong preferential diffusion effects modify the physical processes, which are of importance even for highly turbulent high-pressure conditions. In the present work, Reynolds-averaged Navier-Stokes (RANS) modelling is carried out to investigate pressure and hydrogen content on methane/hydrogen/air flames.
Journal Article

Performance, Fuel Economy, and Economic Assessment of a Combustion Concept Employing In-Cylinder Gasoline/Natural Gas Blending for Light-Duty Vehicle Applications

2019-04-25
Abstract In current production natural gas/gasoline bi-fuel vehicles, fuels are supplied via port fuel injection (PFI). Injecting a gaseous fuel in the intake port significantly reduces the volumetric efficiency and consequently torque as compared to gasoline. In addition to eliminating the volumetric efficiency challenge, direct injection (DI) of natural gas (NG) can enhance the in-cylinder flow, mixing, and combustion process resulting in improved efficiency and performance. A computational fluid dynamics (CFD) approach to model high-pressure gaseous injection was developed and validated against X-ray data from Argonne’s Advanced Photon Source. NG side and central DI of various designs and injection strategies were assessed experimentally along with CFD correlation. Significant effects on combustion metrics were quantified and explained via improved understanding of the in-cylinder flow effects due to NG injection.
Journal Article

Experimental Studies of the Effect of Ethanol Auxiliary Fuelled Turbulent Jet Ignition in an Optical Engine

2019-07-26
Abstract Internal combustion (IC) engines are widely used in automotive, marine, agricultural and industrial machineries because of their superior performance, high efficiency, power density, durability and versatility in size and power outputs. In response to the demand for improved engine efficiency and lower CO2 emissions, advanced combustion process control techniques and more renewable fuels should be adopted for IC engines. Lean-burn combustion is one of the technologies with the potential to improve thermal efficiencies due to reduced heat loss and higher ratio of the specific heats. In order to operate the IC engines with very lean air/fuel mixtures, multiple turbulent jet pre-chamber ignition has been researched and developed to extend the lean-burn limit. Turbulent Jet Ignition (TJI) offers very fast burn rates compared to spark plug ignition by producing multiple ignition sites that consume the main charge rapidly.
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