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Technical Paper

Numerical investigation of Electrostatic Spray Painting Transfer Processes for vehicle Coating

2019-09-16
2019-01-1856
In this study we examined numerically the electrostatic spray transfer processes in the rotary bell spray applicator, which is this case implemented in a full 3D representation. The algorithm implemented and developed for this simulation includes airflow, spray dynamics, tracking of paint droplets and an electrostatic modularized solver to present atomization and in-flight spray phenomena for the spray forming procedure. The algorithm is implemented using the OpenFOAM package. The shaping airflow is simulated via an unsteady 3D compressible Navier-Stokes method. Solver for particle trajectory was developed to illustrate the process of spray transport and also the interaction of airflow and particle that is solved by momentum coupling. As the numerical results in this paper indicates dominant operating parameter voltage setting, further the charge to mass ratio and air-paint flow rate deeply effect the spray shape and the transfer efficiency (TE).
Technical Paper

Optimization of CI Engine Performance and Emissions Fueled by Blends of Alternative Fuels Methyl Ester Using Taguchi and Multi Regression Analysis

2019-09-16
2019-01-1893
Today’s frenetic engine manufacturing and transportation sector and its related traces viz; noise and vibration of our modern societies has adverse effect on environment as well as all of us. Modern research affords us the opportunity to understand the subject better and to develop advance technologies. Widely immediate slogan and goal of all industries might be to improve the performance and reduce emission using alternative fuel while, make the quietest and smoothest running Engines. To, reduce the dependency on diesel fuel (Due to rapid worldwide depletion) Biodiesel is one of the immediate, alternative and complimentary solution. In the Present study, to optimize the operating parameters of the Direct Injection Single Cylinder (5.2 kw) CI engine with respect to Brake Thermal Efficiency (BTE), Carbon monoxide (CO), Oxides of Nitrogen, Hydrocarbons (HC) etc..
Technical Paper

The benefits of using Composite Bearings in Aircraft Shock Absorbers

2019-09-16
2019-01-1898
This paper will use actual examples from aircraft recently introduced into service, to describe the main advantages of changing from the currently used metallic bearings, to composite bearings. Abstract: The introduction of composite bearing in a recently introduced twin aisle aircraft has resulted in: • Weight saving, by replacing bronze bearings with plastic bearings • Lowering of the particle count in the shock absorber oil, (Reduced contamination with metal particles) leading to reduced wear on seals and bearings. Qualification testing showed that Composite Bearings are able to provide longer service life than bronze bearings.
Technical Paper

Effects of In-cylinder flow structures on soot formation and oxidation in a swirl-supported light-duty diesel engine

2019-08-15
2019-24-0009
In this paper, computation fluid dynamics (CFD) simulations are performed to describe the effect of in-cylinder flow structures on the formation and oxidation of soot in a swirl-supported light-duty diesel engine. The focus of the paper is on the effect of swirl motion and injection pressure on late cycle soot oxidation. The structure of the flow at different swirl numbers is studied to investigate the effect that varying swirl number imposes on the coherent flow structures. These coherent flow structures are studied to understand the mechanism that leads to efficient soot oxidation in late cycle. Effect of varying injection pressure at different swirl numbers and the interaction between spray and swirl motions are discussed. The complexity of diesel combustion, especially when soot and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution.
Technical Paper

A Computationally Efficient Progress Variable Approach for In-Cylinder Combustion and Emissions Simulations

2019-08-15
2019-24-0011
The use of complex reaction schemes is accompanied by high computational cost in 3D CFD simulations but is particularly important to predict pollutant emissions in in-cylinder simulations. One solution to tackle this problem is to use tabulated chemistry. The approach presented herein combines pre-tabulated progress variable-based source terms for auto-ignition as well as soot and NOx source terms for advanced emission predictions. The method is coupled to CONVERGE v2.4 via user-coding and tested over various speed and load passenger-car Diesel engine conditions. This work includes the comparison between the combustion progress variable (CPV) model and the on-line chemistry solver in CONVERGE 2.4. Both models are also compared against experimental data by means of combustion and emission parameters. A detailed mechanism comprising 190 species, having n-decane/α-methyl-naphthalene as main fuels, is used for both on-line and tabulated chemistry simulations.
Technical Paper

Computational Chemistry Consortium: surrogate fuel mechanism development, pollutants submechanisms and components library.

2019-08-15
2019-24-0020
The Computational Chemistry Consortium (C3) is dedicated to leading the advancement of combustion and emissions modeling in internal combustion engines. The C3 cluster combines the expertise of different groups involved in combustion research aiming to refine existing chemistry models and to develop more efficient tools for the generation of surrogate and multi-fuel mechanisms, and suitable mechanisms for CFD applications. In addition to the development of more accurate kinetic models for different components of interest in real fuels’ surrogates and for pollutants formation (NOx, PAHs, soot), the core activity of C3 is to develop a tool capable of merging high fidelity kinetics from different sources (i.e. different partners), resulting in a high-fidelity model for a specific application.
Technical Paper

Experimental and numerical investigation of the maximum pressure rise rate for an LTC concept in a single cylinder CI engine

2019-08-15
2019-24-0023
In the foreseeable future, the transportation sector will continue to rely on internal combustion engines. Therefore, reduction of engine-out emissions and increase in engine efficiency are important goals to meet future legislative regulations and restricted fuel resources. One viable option, which provides lower peak temperatures and increased mixture homogeneity and thus simultaneously reduces nitric oxide as well as soot, is a low-temperature combustion (LTC) concept. However, this might result in an increase of unburnt hydrocarbon, carbon monoxide, and combustion noise due to early combustion phasing and lower engine efficiency. Various studies show that these drawbacks can be compensated by advanced injection strategies, e.g. by employing multiple injections. The aim of this work is to identify the optimum injection strategy, which enables a wide range of engine operating points in LTC mode with reduced engine-out emissions.
Technical Paper

Potential to reduce nano-particle emission in SG-DISI engine with normal butane.

2019-08-15
2019-24-0022
Under lean stratified combustion, differed from the stoichiometric homogeneous charge combustion, flame could propagate through extremely rich air-fuel mixture. The rich mixture causes considerable amount of particulate matter, but, due to large effect of efficiency improvement, the attractive point is on fuel economy compare to homogeneous charge SI combustion. The easiest way to reduce particulate matter is changing fuel to gaseous hydrocarbon, to minimize evaporating and mixing period. In this study, to reduce the particulate emission and to develop the way to mitigation of emission, the emission data of particulate under low and medium-low load conditions from normal butane fueled research engine are dealt to optimize combustion strategies, with respect to injection and ignition. Especially, particulate number density were collected in the research engine, and the causes of particulate formation were speculated with visualized combustion data.
Technical Paper

Effects of Droplet Behaviors on Fuel Adhesion of Flat Wall Impinging Spray injected by a DISI Injector

2019-08-15
2019-24-0034
Owing to the short impingement distance and high injection pressure, it is difficult to avoid the fuel spray impingement on the combustion cylinder wall and piston head in Direct Injection Spark Ignition (DISI) engine, which is a possible source of hydrocarbons and soot emission. For better understanding of the mechanisms behind the spray-wall impingement, the fuel spray and adhesion on a flat wall using a mini-sac injector with a single hole was examined. The microscopic characteristics of impinging spray were investigated through Particle Image Analysis (PIA). The droplet size and velocity were compared before and after impingement. The adhered fuel on the wall was measured by Refractive Index Match-ing (RIM). Time-resolved fuel adhesion evolution as well as adhesion mass, area, and thickness were discussed. Moreover, the relationships between droplets behaviors and fuel adhesion on the wall were discussed.
Technical Paper

Experimental High Temperature Analysis of a Low-Pressure Diesel Spray for DPF Regeneration

2019-08-15
2019-24-0035
In the current automotive scenario, particulate filter technology is mandatory in order to attain emission limits in terms of particulate matter for Diesel engines. Despite DPF is often considered a mature technology, significant issues can derive from the use of the engine fuel injectors to introduce in the exhaust pipe the fuel needed to light on the particulate matter in the filter during its regeneration, primarily the lubricant oil dilution with fuel a consequence of significant spray impact on the cylinder liner. As an alternative, the fuel required to start regeneration can be introduced in the exhaust pipe by an auxiliary low pressure injector spraying in the hot exhaust gas stream. In this conditions, the spray evolution and its possible interaction with the surrounding gas stream are relevant in order to better identify the overall layout of the system, so to have the fuel vaporized at the DPF inlet section.
Technical Paper

Gasoline Spray_Models_Calibration_Under_Diesel_Engine_Like_Conditions

2019-08-15
2019-24-0032
Atomization of liquid fuel jets is critical to the performance of Internal Combustion (IC) engine, as it plays a key role in affecting mixture formation, combustion efficiency and soot emissions. In the Gasoline Compression Ignition (GCI) engine investigation, the experimental measurements on the gasoline injection into diesel engine like condition, shows the difficulty in matching the liquid penetration length when the diesel spray model is used. Additional tests performed at lower ambient densities, seen in early injection, revealed a lot of information on liquid jet dynamics behavior. It requires a lot of model calibration effort in matching the measured liquid and vapor penetration length under different ambient pressure conditions. It is found that using droplet Sauter Mean Diameter distribution model shows better match with experiment at low density condition, whereas the KH-ACT breakup model correlates well with measurement at high density condition.
Technical Paper

Morphological characterisation of gasoline soot-in-oil: development of semi-automated 2D-TEM and comparison with novel high-throughput 3D-TEM

2019-08-15
2019-24-0042
Morphology of soot nanoparticles is characteristically complex and 3-dimensional, and plays a defining role in soot-related phenomena. Morphological characterisation of soot is essential to understand the extent of such effects, including harm to human health, and develop strategies to mitigate them. Use of 2D-TEM for characterisation is associated with numerous and significant sources of error and uncertainty related to a 2D-3D information gap. Volume reconstruction by 3D-TEM avoids many of these sources of error, and has been shown in simulation studies to be highly accurate. However, the technique has traditionally been too slow to permit study of enough individual structures to satisfactorily characterise a bulk soot-sample. Similarly, the prevalence of manual image processing in 2D-TEM studies of soot can limit characterisations to as few as 50 individual particles per sample.
Technical Paper

Experimental tests on the feasibility of passive regeneration in a catalytic DPF at the exhaust of a light-duty Diesel engine

2019-08-15
2019-24-0045
Diesel engines are attractive thanks to good performance in terms of fuel consumption, drivability, power output and efficiency. Nevertheless in the last years, increasing restrictions have been imposed to particulate emissions, concerning both mass (PM) and number (PN). Different technologies have been proposed to meet emissions standards and the wall-flow Diesel Particulate Filter (DPF) is currently the most common after-treatment system used to trap PM from the exhaust gases. This technology exhibits good features such that it can be regenerated to remove any accumulation of PM. However, this process involves oxidation of the filtered PM at a high temperature through after and post fuel injection strategies, which results in an increase of fuel consumption and may lead to physical damages of the filter in the long term. This work deals with the experimental testing of a catalytic silicon carbide (SiC) wall flow DPF, aiming at decreasing the soot oxidation temperature.
Technical Paper

Semi-volatile Organic Compounds From a Combined Dual Port Injection/Direct-Injection Technology Light-Duty Gasoline Vehicle

2019-08-15
2019-24-0051
Gasoline direct injection (GDI) has changed the exhaust composition in comparison with the older port fuel injection (PFI) systems. More recently, light-duty vehicle engine manufactures have combined these two technologies to take advantage of the knock benefits and fuel economy of GDI with the low particulate emission of PFI. These dual injection strategy engines have made a significant change in the combustion emission composition produced by these engines. Understanding the impact of these changes is essential for automotive companies and aftertreatment developers. A novel sampling system was designed to sample the entire exhaust generated by a dual injection strategy gasoline vehicle using the United States Federal Test Procedure (FTP). This sampling system was capable of measuring the regulated emissions as well as collecting the entire exhaust from the vehicle for unregulated emissions.
Technical Paper

Assessing exhaust toxicity with biological detector: Configuration of portable air-liquid interface human lung cell model exposure system, sampling train and test conditions.

2019-08-15
2019-24-0050
Air pollution remains to be one of the leading causes of premature death worldwide, with significant share attributed to particulate matter and reactive nitrogen compounds from mobile sources. Due to discrepancies between legislative metrics and health effects, and between laboratory tests and real driving, health-relevant metric applicable to real driving conditions are sought to evaluate the effects of emerging legislation, technologies and fuels. Models of human lung air-liquid interface have been recently explored to simulate effects of exposure to the whole exhaust. In this study, a compact exposure system, utilizing commercially available inserts with 3D in-vitro model of human lung cells, has been designed in-house with the vision of mobile use, minimizing size and power consumption. Due to deposition and reentrainment of semivolatile compounds in a full-flow dilution tunnel, most studies sampled raw exhaust and used a constant dilution ratio.
Technical Paper

Chemical and Physical Characterization of Organic Particulate Matter from Last Generation Exhaust Aftertreatment System of Medium Duty Diesel Engine

2019-08-15
2019-24-0053
Particulate Matter from Euro 6 Medium Duty diesel engine was analyzed from engine-out, downstream of particulate filter (DPF), and up to the exit of a selective catalytic reactor (SCR) to characterize its chemical and physical nature. Particular attention was devoted to the analysis of particles down to 23 nm. An array of chemical, physical and spectroscopic techniques (Gas chromatography coupled with mass spectrometry (GC-MS), mobility analyzer, UV-visible absorption and fluorescence spectroscopy) was applied for characterizing the organic particulate matter (PM, constituted of polycyclic aromatic hydrocarbons (PAH), heavy aromatic compounds, soot) in the exhaust. The engine was operated at “full-load” (100% of the total power, representing the best performance of the engine operation) condition, and at different engine speeds. Results showed that the DPF efficiency was greater than 96% in the reduction of the sub 23 nm particles across the speeds range.
Technical Paper

Solid nucleation mode engine exhaust particles detection at high temperatures with an advanced half-mini DMA

2019-08-15
2019-24-0052
Diesel and gasoline direct injection engines emit nucleation mode particles either under special conditions or as part of their size distribution, respectively. Currently, European legislation excludes nucleation mode particles as particle number vehicle emission measurements are limited down to 23 nm. The rationale behind such cut-off size is based on the avoidance of significant uncertainties created during sampling and measuring sub-23 nm solid particles. However, the sub-23 nm particles draw high attention since a large fraction of particles emitted by modern vehicles lies in this size range. In this study we investigate the possibility of accurate nucleation mode particles detection by using the Advanced Half-Mini Differential Mobility Analyzer (HM-DMA). The Advanced HM-DMA system is able to classify aerosol particles in the mobility size range 4 – 30 nm with high resolution and fast spectrum acquisition that can accommodate a hot sample flow up to 200°C.
Technical Paper

Emissive behavior of a heavy-duty SI gas engine during WHTC

2019-08-15
2019-24-0121
In the arduous aim to reduce petroleum fuel consumption and toxic emissions, gaseous fuels can represent an alternative solution for heavy duty applications with respect to conventional liquid fuels. At the same time, the imposition of more stringent emissions regulations in the transport sector, is a crucial aspect to be considered also for the development of future gas engines. Scope of the present paper was to characterize a heavy duty spark ignition engine, under development for Euro VI compliance, with a particular focus on exhaust particulate emissions. In this sense, the engine was installed on a dynamic test bench, accurately instrumented to analyze combustion evolution, performance and exhaust pollutant emissions, along the World Harmonized Transient Cycle (WHTC).
Technical Paper

Large Eddy Simulations and Tracer-LIF Diagnostics of wall film dynamics in an optically accessible GDI research engine

2019-08-15
2019-24-0131
Large Eddy Simulations (LES) and tracer-based Laser Induced Fluorescence (LIF) measurements have been performed to study the dynamics of fuel wall-films on the piston top of an optically accessible, four-valve pent-roof GDI research engine for a total of eight operating conditions. Starting from a reference point, the systematic variations include changes in engine speed (600; 1,200 and 2,000 RPM) and load (WOT and 500 mbar intake pressure); concerning the fuel path the Start Of Injection (SOI=360°, 390° and 420° CA after gas exchange TDC) as well as the injection pressure (10, 20 and 35 MPa) have been varied. For each condition, 40 experimental images were acquired phase-locked at 10° CA intervals after SOI, providing valuable insights with respect to the wall film dynamics in terms of spatial extent, thickness and temperature.
Technical Paper

CFD modeling and validation of the ECN Spray G experiment under a wide range of operating conditions

2019-08-15
2019-24-0130
The increasing diffusion of gasoline direct injection (GDI) engines requires a more detailed and reliable description of the phenomena occurring during the fuel injection process. Currently, one drawback of GDI engines is represented by the impingement on the piston wall, due to typically adopted hollow-cone fuel sprays, which can lead to high emissions of unburned hydrocarbons and soot formation. Within this context, the extensive validation of multi-dimensional models by means of experimental data represents a fundamental task to accurately predict the physical phenomena characterizing the injected spray. The aim of this work was to simulate with OpenFOAM different operating conditions of the 8-hole, ECN Spray G injector placed into a constant volume vessel. The resulting developments of the jet plumes were assessed, along with the physical effects of injection pressure and wall temperature on the wall impingement phenomenon.
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