bluuebunny/crossref_metadata_2025 huggingface dataset:
General Capability of Parametric 3D Blade Design Tool for Turbomachinery
Authors: Siddappaji Kiran , Turner Mark G. , Merchant Ali
Published: July 2013

A design tool for generating 3D blades for various turbomachinery applications using a parametric approach has been developed. The tool can create a variety of 3D blade geometries based on only a few basic parameters and limited interaction with a CAD system. A general approach for creating the blade geometries is implemented which makes it robust and easy to create different 3D blade shapes for various turbomachinery components. The geometric and aerodynamic parameters are used to create 2D airfoils and these airfoils are stacked on the desired stacking axis. The tool generates a specified number of 2D blade sections in a 3D Cartesian coordinate system. These sections can be lofted in a CAD package to obtain a solid 3D blade model, which has been demonstrated using Unigraphics-NX and Solidworks.

The geometry modeler can also be used for generating 3D blades with special features like bent tip, split tip and other concepts, which can be explored with minimum changes to the blade geometry. The use of control points for the definition of splines makes it easy to modify the blade shapes quickly and smoothly to obtain the desired blade model. Blade shapes for axial turbomachines, radial turbomachines and wind turbines are generated to show the general capability of the tool. Other novel blade shapes are also shown which shows the full utility of this tool when integrated with CAD. The executable of the code that generates sections is freely available on the web.
Multiphase CFD Model Development for a Rotating Centrifugal Separator
Authors: DeMore Daniel , Maier William
Published: July 2013

The present paper describes the development of a Computational Fluid Dynamic (CFD) modeling approach suitable for the analysis, design, and optimization of rotating centrifugal separator stage geometries. The Homogeneous Multiple Size Group (MUSIG) model implemented in the commercial code CFX V13.0 was utilized as a basis for the CFD modeling method. The model was developed through a series of studies to understand the impact of droplet size distribution, particle coalescence, rotor/stator interface treatment, and mesh resolution on the prediction of separation efficiency for a given rotating separator geometry. This model was then validated against the OEM’s extensive in-house experimental separation testing database. The resulting CFD modeling method is shown to adequately reproduce observed trends in separation performance over a wide range of operating conditions.
Optimization of Turbomachinery Flow Surfaces Applying a CFD-Based Throughflow Method
Authors: Pasquale David , Persico Giacomo , Rebay Stefano
Published: July 2013

This work proposes an optimization strategy for the preliminary stage of turbomachinery design, based on the application of a throughflow code in the context of a fully automated optimization strategy. The code solves for the circumferentially-averaged flow equations, including the effects of aerodynamic and friction forces and of blade thickness; the outcome of the code is the flow distribution on the meridional surface. In this research the definition of an ‘optimal’ mean flow surface is the final aim of a multi-objective optimization procedure, in which non-concurrent goals are simultaneously considered. Evolutionary algorithms are used in the global optimization process, based on the coupling of a Genetic Algorithm with a metamodel.

The optimization method is applied to a low speed axial compressor, for which the optimization goals are the minimization of aerodynamic loss and discharge kinetic energy at the exit of the stage, as well as the uniformity of work exchange along the blade span. The method proves to match all the objectives, providing a clear improvement with respect to classical and well-established design methods.
Flow Control in an Aggressive Inter-Turbine Duct Using Low Profile Vortex Generators
Authors: Zhang Yanfeng , Hu Shuzhen , Zhang Xue Feng , Benner Michael , Vlasic Edward
Published: July 2013

This paper presents the experimental investigation of the flow in an aggressive inter-turbine duct (AITD). The goal is to improve the understanding of the flow mechanisms within the AITD and of the underlying physics of low-profile vortex generators (LPVGs).

The flow structures in the AITD are dominated by counter-rotating vortices and boundary layer separations in both the casing and hub regions. At the first bend of the AITD, the casing boundary layer separates in a 3D mode because of the upstream wakes; this is followed by a massive 2D boundary layer separation. Due to the effect of the radial pressure gradient at the first bend, the streamwise vorticity generated by the casing 3D separation stays close to the casing endwall, and later mixes with the casing counter-rotating vortices formed at the second bend.

By using LPVGs with different configurations installed on the casing, the casing boundary layer separation is significantly reduced. The streamwise vortices generated by the LPVGs have the potential to generate another pair of counter-rotating vortices at the AITD second bend, which help to delay/prevent the boundary layer separation. Therefore, the total pressure loss in the AITD was significantly reduced.
The Effect of Reynolds Number on a Transonic Swept Fan OGV in a Small Turbofan Engine
Authors: Sonoda Toyotaka , Arima Toshiyuki , Endicott Giles , Olhofer Markus , Sendhoff Bernhard
Published: July 2013

In this paper, Reynolds effects on a transonic swept fan outlet guide vane (OGV) in a small turbofan engine are evaluated using a CFD model, successfully assessed with respect to experimental data. The flow-fields are evaluated at two Reynolds number conditions, a high Reynolds condition (corresponding to take-off conditions) and a low Reynolds number condition (corresponding to cruise conditions). The CFD results show large differences in the overall OGV performance between these two points. The flow mechanism for the deterioration in the OGV’s performance at the low Reynolds number condition is shown. Finally a new idea for improving the OGV performance is proposed.
Comparison Between Unstructured and Structured Meshes With Different Turbulence Models for a High Pressure Turbine Application
Authors: Tomita Jesuino Takachi , da Silva Lucilene Moraes , da Silva Diego Thomas
Published: July 2013

For the CFD community the mesh generation is still one of the most important stages to obtain a good flow solution based on the full Navier-Stokes equations. For turbomachinery blade passages this task is not straightforward mainly due to the 3D domain and the complex geometries involved. The mesh quality and and elements distribution, orthogonality, smoothing, aspect ratio and angles are very important to guarantee a good numerical stability and solution accuracy. Moreover, the structure of the mesh inside the boundary-layer should be built carefully mainly in the regions where there are horseshoe vortices and tip leakage flow. In this work, the 3D turbulent flow is calculated and compared for structured and unstructured meshes including two equation models and Reynolds stress models. A high pressure turbine with 4.0 total-to-total pressure ratio is used in this study. A commercial software is used for mesh generation and flow calculation. The results are presented comparing the pressure ratio and efficiency from numerical solutions and experimental data and flow properties distributions along the blade span.
Simulation of Radial Compressor Aeroacoustics Using CFD
Authors: Mendonça Fred , Baris Onur , Capon Geoff
Published: July 2013

This paper focuses on the application of CFD to the prediction of radial compressor aeroacoustics. It concentrates mainly on automotive turbocharger operations in the low mass-flow range where blade leading-edge and tip separation reduce the compressor performance and induce transient flow behaviour. Whereas the blade-passing is tonal and at high frequency, usually beyond the human hearing range, transience in the flow are turbulence-dominated, broad-band in nature, and in magnitude a significant source of aeroacoustics which appears well within the range of peak human hearing (1–5kHz). Other noise sources occur due to distortions in the flow upstream of the compressor face, and rotating stall.

The simulation methodology enumerated here pays attention to all the above flow-induced aeroacoustics. Due consideration is given to turbulence modelling, to ensure that both the narrow-band and broad-band sources are directly resolved in the CFD. Appropriate discretisation practices are adopted, so as to capture both turbulent-convection and sound-propagation mechanisms. Pressure-wave non-reflective boundary conditions are applied to the computational boundaries to remove any artificial resonances in the domain.

STAR-CCM+, the commercial CFD code used here, was previously benchmarked against experimental data for the same compressor under ideal installation conditions, then the compressor performance assessed under real installation conditions [1]. The main foci of the studies reported here are to exploit possible improvements in modelling of the device performance and efficiency curves using more detailed wall modelling, comparing low-y+ versus high-y+ wall resolution, and to explore the viability for transient CFD calculations to capture the noise sources in the compressor at the challenging low mass flow end of the performance characteristic.
Advanced Thermal Management for Modern Diesel Engines: Optimized Synergy Between Engine Hardware and Software Intelligence
Authors: Körfer Thomas , Busch Hartwig , Kolbeck Andreas , Severin Christopher , Schnorbus Thorsten , Honardar Sharareh
Published: July 2013

Both, the continuous tightening of the exhaust emission standards and the global efforts for a significant lowering of CO2 output in public traffic display significant developments for future diesel engines. These engines will utilize not only the mandatory Diesel oxidation catalyst (DOC) and particulate trap (DPF), but also a DeNOx aftertreatment system as well — at least for heavier vehicles. The DOC as well as actually available sophisticated DeNOx aftertreatment technologies, i.e. LNT and SCR, depends on proper exhaust gas temperatures to achieve a high conversion rates. This aspect becomes continuously critical due to intensified measures for CO2 reduction, which will conclude in a drop of exhaust gas temperatures. Furthermore, this trend has to be taken into account regarding future electrification and hybridization scenarios. In order to ensure the high NOx conversion rates in the EAS intelligent temperature management strategies will be required, not only based on conventional calibration measures, but also a further upgrade of the engine hardware.

Advanced split-cooling and similar thermal management technologies offer the merit to lower CO2 emissions on one hand and increase exhaust gas temperature at cold start and warm-up simultaneously on the other hand. Besides this, also variable valve train functionalities deliver a substantial potential of active thermal management. In the context of this paper various concepts for exhaust gas temperature management are investigated and compared. The final judgment will focus on the effectiveness concerning real exhaust temperature increase vs. corresponding fuel economy penalty. Further factors, like operational robustness, consequences on operational strategies and related software algorithms as well as cost are assessed. The utilized reference engine in this advanced program is represented by a refined I-4 research engine to achieve best combustion efficiency at minimal engine-out emissions. The detailed studies were performed with an injection strategy, featuring one pilot injection and one main injection event, and an active, advanced closed-loop combustion control. The engine used in this study allows fulfillment of Euro 6 and Tier 2 Bin 5 emissions standards, while offering high power densities above 80 kW/ltr.

As a résumé, it can be stated, that with all accomplished variations a significant increase in temperature downstream low pressure turbine can be achieved. The PI and PoI quantities define dominant parameters for emission formation under cold and warm conditions. By using an exhaust cam-phaser CO-, HC- and NOx emissions can be significantly lowered, separating VVT functions from the other investigated strategies.
Hydrotreated Algae Renewable Fuel Performance in a Military Diesel Engine
Authors: Caton Patrick A. , Williams Sherry A. , Kamin Richard A. , Luning-Prak Dianne , Hamilton Leonard J. , Cowart Jim S.
Published: July 2013

A vegetable oil from algae has been processed into a Hydrotreated Renewable Diesel (HRD) fuel. This HRD fuel was tested in an extensively instrumented legacy military diesel engine along with conventional Navy diesel fuel. Both fuels performed well across the speed-load range of this HMMWV engine. The high cetane value of the HRD (77 v. 43) leads to significantly shorter ignition delays with associated longer combustion durations and modestly lower peak cylinder pressures as compared to diesel fuel operation. Both brake torque and brake fuel consumption are better (5–10%) with HRD due to the cumulative IMEP effect with moderatly longer combustion durations. Carbon dioxide emmisions are considerably lower with HRD due to the improved engine efficiency as well the more advantageous hydrogen-carbon ratio of this HRD fuel.
Model-Based Calibration of a Biogas Engine Control System
Authors: Flory Michael , Hiltner Joel , Hardenburger Clay
Published: July 2013

Pipeline natural gas composition is monitored and controlled in order to deliver high quality, relatively consistent gas quality in terms of heating value and detonation characteristics to end users. The consistency of this fuel means gas-fired engines designed for electrical power generation (EPG) applications can be highly optimized. As new sources of high quality natural gas are found, the demand for these engines is growing. At the same time there is also an increasing need for EPG engines that can handle fuels that have wide swings in composition over a relatively short period of time. The application presented in this paper is an engine paired with an anaerobic digester that accepts an unpredictable and varying feedstock. As is typical in biogas applications, there are exhaust stream contaminants that preclude the use of an oxygen or NOx sensor for emissions feedback control. The difficulty with such a scenario is the ability to hold a given exhaust gas emission level as the fuel composition varies. One challenge is the design of the combustion system hardware. This design effort includes the proper selection of compression ratio, valve events, ignition timing, turbomachinery, etc. Often times simulation tools, such as a crank-angle resolved engine model, are used in the development of such systems in order to predict performance and reduce development time and hardware testing. The second challenge is the control system and how to implement a robust control capable of optimizing engine performance while maintaining emissions compliance. Currently there are limited options for an OEM control system capable of dealing with fuels that have wide swings in composition. Often times the solution for the engine packager is to adopt an aftermarket control system and apply this in place of the control system delivered on the engine. The disadvantage to this approach is that the aftermarket controller is not calibrated and so the packager is faced with the task of developing an entire engine calibration at a customer site. The controller must function well enough that it will run reliably during plant start-up and then eventually prove capable of holding emissions under typical operating conditions. This paper will describe the novel use of a crank-angle resolved four-stroke engine cycle model to develop an initial set of calibration values for an aftermarket control system. The paper will describe the plant operation, implementation of the aftermarket controller, the model-based calibration methodology and the commissioning of the engine.
Investigating Trends in Simulated Ignition Timing Across a Wide Range of Conditions Including Fuel Reactivity
Authors: Johnson Michael V. , Goldsborough S. Scott , Smith Timothy A. , McConnell Steven S.
Published: July 2013

Continued interest in kinetically-modulated combustion regimes, such as HCCI and PCCI, poses a significant challenge in controlling the ignition timing due to the lack of direct control of combustion phasing hardware available in traditional SI and CI engines. Chemical kinetic mechanisms, validated based on fundamental data from experiments like rapid compression machines and shock tubes, offer reasonably accurate predictions of ignition timing; however utilizing these requires high computational cost making them impractical for use in engine control schemes. Empirically-derived correlations offer faster control, but are generally not valid beyond the narrow range of conditions over which they were derived.

This study discusses initial work in the development of an ignition correlation based on a detailed chemical kinetic mechanism for three component gasoline surrogate, composed of n-heptane, iso-octane and toluene, or toluene reference fuel (TRF). Simulations are conducted over a wide range of conditions including temperature, pressure, equivalence ratio and dilution for a range of tri-component blends in order to produce ignition delay time and investigate trends in ignition as pressure, equivalence ratio, temperature and fuel reactivity are varied. A modified, Arrhenius-based power law formulation will be used in a future study to fit the computed ignition delay times.
Numerical Comparative Analysis of In-Cylinder Tumble Flow Structures in Small PFI Engines Equipped by Heads Having Different Shapes and Squish Areas
Authors: Falfari Stefania , Bianchi Gian Marco , Nuti Luca
Published: July 2013

For increasing the thermal engine efficiency, faster combustion and low cycle-to-cycle variation are required. In PFI engines the organization of in-cylinder flow structure is thus mandatory for achieving increased efficiency. In particular the formation of a coherent tumble vortex with dimensions comparable to engine stroke largely promotes proper turbulence production extending the engine tolerance to dilute/lean mixture. For motorbike and scooter applications, tumble has been considered as an effective way to further improve combustion system efficiency and to achieve emission reduction since layout and weight constraints limit the adoption of more advanced concepts. In literature chamber geometry was found to have a significant influence on bulk motion and turbulence levels at ignition time, while intake system influences mainly the formation of tumble vortices during suction phase. The most common engine parameters believed to affect in-cylinder flow structure are:

1. Intake duct angle;

2. Inlet valve shape and lift;

3. Piston shape;

4. Pent-roof angle.

The present paper deals with the computational analysis of three different head shapes equipping a scooter/motorcycle engine and their influence on the tumble flow formation and breakdown, up to the final turbulent kinetic energy distribution at spark plug. The engine in analysis is a 3-valves pent-roof motorcycle engine. The three dimensional CFD simulations were run at 6500 rpm with AVL FIRE code on the three engines characterised by the same piston, valve lift, pent-roof angle and compression ratio. They differ only in head shape and squish areas. The aim of the present paper is to demonstrate the influence of different head shapes on in-cylinder flow motion, with particular care to tumble motion and turbulence level at ignition time. Moreover, an analysis of the mutual influence between tumble motion and squish motion was carried out in order to assess the role of both these motions in promoting a proper level of turbulence at ignition time close to spark plug in small 3-valves engines.
A Reduced Chemical Kinetic Mechanism for CFD Simulations of High BMEP, Lean-Burn Natural Gas Engines
Authors: Martinez-Morett David , Tozzi Luigi , Marchese Anthony J.
Published: July 2013

Recent developments in numerical techniques and computational processing power now permit time-dependent, multi-dimensional computational fluid dynamic (CFD) calculations with reduced chemical kinetic mechanisms (approx. 20 species and 100 reactions). Such computations have the potential to be highly effective tools for designing lean-burn, high BMEP natural gas engines that achieve high fuel efficiency and low emissions. Specifically, these CFD simulations can provide the analytical tools required to design highly optimized natural gas engine components such as pistons, intake ports, precombustion chambers, fuel systems and ignition systems. To accurately model the transient, multi-dimensional chemically reacting flows present in these systems, chemical kinetic mechanisms are needed that accurately reproduce measured combustion data at high pressures and lean conditions, but are of sufficient size to enable reasonable computational times. Presently these CFD models cannot be used as accurate design tools for application in high BMEP lean-burn gas engines because existing detailed and reduced mechanisms fail to accurately reproduce experimental flame speed and ignition delay data for natural gas at high pressure (40 atm and higher) and lean (0.6 equivalence ratio (ϕ) and lower) conditions. Existing methane oxidation mechanisms have typically been validated with experimental conditions at atmospheric and intermediate pressures (1 to 20 atm) and relatively rich stoichiometry. These kinetic mechanisms are not adequate for CFD simulation of natural gas combustion in which elevated pressures and very lean conditions are typical. This paper provides an analysis, based on experimental data, of the laminar flame speed computed from numerous, detailed chemical kinetic mechanisms for methane combustion at pressures and equivalence ratios necessary for accurate high BMEP, lean-burn natural gas engine modeling. A reduced mechanism that was shown previously to best match data at moderately lean and high pressure conditions was updated for the conditions of interest by performing sensitivity analysis using CHEMKIN. The reaction rate constants from the most sensitive reactions were appropriately adjusted in order to obtain a better agreement at high pressure lean conditions. An evaluation of this adjusted mechanism, “MD19”, was performed using Converge CFD software. The results were compared to engine data and a remarkable improvement on combustion performance prediction was obtained with the MD19 mechanism.
Assessment of Thermo-Structural Effects on EHL Piston Skirt Lubrication
Authors: Littlefair B. , Howell-Smith S. , Rahnejat H. , Theodossiades S.
Published: July 2013

The in situ profiles of the piston skirt and cylinder bore surface are subject to thermo-elastic global deformation due to differential operating temperatures and forces. In operation, a lubricant film is entrained into and pressurized within the gap between these profiles. This film not only supports the prevailing contact load, but also inhibits direct interaction of surfaces, thus reducing friction and thereby improving fuel efficiency. The reduction of reciprocating mass in motorsport applications has been achieved through the use of partial circumferential skirts for a number of years now. The response of the shape to both mechanical and structural loadings differs from the classic full circumferential skirt studies. This paper provides a ‘snapshot’ into how the inherent piston side load is supported by the piston skirt. It highlights the importance of the operational temperature on the skirt profile, conjunctional gap and the lubricant film. Additionally, it shows how a given piston skirt shape and its structural stiffness perform in operation.
Cyclic Combustion Variations in Dual Fuel Partially Premixed Pilot-Ignited Natural Gas Engines
Authors: Srinivasan K. K. , Krishnan S. R. , Qi Y.
Published: July 2013

Dual fuel pilot ignited natural gas engines are identified as an efficient and viable alternative to conventional diesel engines. This paper examines cyclic combustion fluctuations in conventional dual fuel and in dual fuel partially premixed low temperature combustion (LTC) at 1700 rev/min and 6 bar brake mean effective pressure (bmep). Conventional dual fueling with 95% (energy basis) natural gas (NG) substitution reduces NOx emissions by almost 90%t relative to straight diesel operation; however, this is accompanied by 98% increase in HC emissions, 10 percentage points reduction in fuel conversion efficiency (FCE) and 12 percentage points increase in COVimep. Dual fuel LTC is achieved by injection of a small amount of diesel fuel (2–3 percent on an energy basis) to ignite a premixed natural gas–air mixture to attain very low NOx emissions (less than 0.2 g/kWh). Cyclic variations in both combustion modes were analyzed by observing the cyclic fluctuations in start of combustion (SOC), peak cylinder pressures (Pmax), combustion phasing (Ca50), and the separation between the diesel injection event and Ca50 (termed “relative combustion phasing”). For conventional dual fueling, as % NG increases, Pmax decreases, SOC and Ca50 are delayed, and cyclic variations increase. For dual fuel LTC, as diesel injection timing is advanced from 20° to 60°BTDC, the relative combustion phasing is identified as an important combustion parameter along with SoC, Pmax, and CaPmax. For both combustion modes, cyclic variations were characterized by alternating slow and fast burn cycles, especially at high %NG and advanced injection timings. Finally, heat release return maps were analyzed to demonstrate thermal management strategies as an effective tool to mitigate cyclic combustion variations, especially in dual fuel LTC.
Numerical Simulation of Direct Injection Engine With Using Porous Medium
Authors: Mohammadi Arash , Jazayeri Ali , Ziabasharhagh Masoud
Published: July 2013

Porous media (PM) has interesting advantages in compared with free flame combustion due to the higher burning rates, the increased power range, the extension of the lean flammability limits, and the low emissions of pollutants. Future clean internal combustion (IC) engines should have had minimum emissions level (for both gaseous and particulate matter) under possible lowest fuel consumption permitted in a wide range of speed, loads and having good transient response. These parameters strongly depend on mixture formation and combustion processes which are difficult to be controlled in a conventional engine. This may be achieved by realization of homogeneous combustion process in engine. This paper deals with the simulation of direct injection IC engine equipped with a chemically inert PM, with cylindrical geometry to homogenize and stabilize the combustion of engine. A 3D numerical model for PM engine is presented in this study based on a modified version of the KIVA-3V code. Due to lack of any published data for PM engines, numerical results of thermal and combustion wave propagation in a porous medium are compared with experimental data of lean methane-air mixture under filtration in packed bed and very good agreement is seen. For PM engine simulation methane as a fuel is injected directly inside hot PM that is assumed, mounted in cylinder head. Lean mixture is formed and volumetric combustion occurs in PM and in-cylinder. Mixture formation, pressure and temperature distribution in both phases of PM and in-cylinder fluid with the production of pollutants CO and NO and also effects of injection time in the closed part of the cycle are studied.
A Numerical Investigation of Combustion Chamber Geometry Effects on Natural Gas Direct Injection Properties in a SI Engine With Centrally Mounted Multi-Hole Injector
Authors: Yadollahi Bijan , Boroomand Masoud
Published: July 2013

Due to the vast resources of natural gas (NG), it has emerged as an alternative fuel for SI internal combustion engines in recent years. The need to have better fuel economy and less emission especially that of greenhouse gases has resulted in development of NG fueled engines. Direct injection of natural gas into the cylinder of SI internal combustion engines has shown great potential for improvement of performance and reduction of engine emissions especially CO2 and PM. Direct injection of NG into the cylinder of SI engines is rather new thus the flow field phenomena and suitable configuration of injector and combustion chamber geometry has not been investigated completely.

In this study a numerical model has been developed in AVL FIRE software to perform investigation of direct natural gas injection into the cylinder of spark ignition internal combustion engines. In this regard, two main parts have been taken into consideration aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multidimensional numerical simulation of transient injection process, mixing and flow field have been performed via different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature.

In the second part, using the moving mesh capability, the validated model has been applied to methane injection into the cylinder of a direct injection engine. Five different piston head shapes have been taken into consideration in investigations. An inwardly opening multi-hole injector has been adapted to all cases. The injector location has been set to be centrally mounted. The effects of combustion chamber geometry have been studied on mixing of air-fuel inside cylinder via quantitative and qualitative representation of results. Based on the results, suitable geometrical configuration for a NG DI engine has been discussed.
Powertrain Waste Heat Recovery: A Systems Approach to Maximize Drivetrain Efficiency
Authors: Laboe Kevin , Canova Marcello
Published: July 2013

Up to 65% of the energy produced in an internal combustion engine is dissipated to the engine cooling circuit and exhaust gases [1]. Therefore, recovering a portion of this heat energy is a highly effective solution to improve engine and drivetrain efficiency and to reduce CO2 emissions, with existing vehicle and powertrain technologies [2,3].

This paper details a practical approach to the utilization of powertrain waste heat for light vehicle engines to reduce fuel consumption. The “Systems Approach” as described in this paper recovers useful energy from what would otherwise be heat energy wasted into the environment, and effectively distributes this energy to the transmission and engine oils thus reducing the oil viscosities. The focus is on how to effectively distribute the available powertrain heat energy to optimize drivetrain efficiency for light duty vehicles, minimizing fuel consumption during various drive cycles. To accomplish this, it is necessary to identify the available powertrain heat energy during any drive cycle and cold start conditions, and to distribute this energy in such a way to maximize the overall efficiency of the drivetrain.
Retracted: “Development of an Electronic Fuel Injection System for a 4-Stroke Locomotive Diesel Engine” [ASME 2012 Internal Combustion Engine Division Spring Technical Conference, Torino, Piemonte, Italy, May 6–9, 2012, Conference Sponsors: Internal Combustion Engine Division, ISBN: 978-0-7918-4466-3, Copyright © 2012 by ASME. Paper No. ICES2012-81163, pp. 93-99; 7 pages; doi: 10.1115/ICES2012-81163]
Authors: ASME
Published: July 2013

Reason: This paper was removed as a dual publication. Please see https://asmedigitalcollection.asme.org/ICEF/proceedings/ICEF2012/55096/83/238117. October 2, 2020.

Copyright © 2020 by ASME
Modeling the Thermal Behavior of Internal Combustion in Hybrid Electric Vehicles With and Without Exhaust Gas Heat Recirculation
Authors: Donateo Teresa , Pacella Damiano
Published: July 2013

A first-order lumped-parameter model for the prediction of thermal behavior of a single-cylinder gasoline engine for Hybrid Electric Vehicles (HEVs) has been implemented. The model is coupled with a zero-dimension in-cylinder model that evaluates the working cycle of the engine according to the actual operating conditions and calculates the temperature of the exhaust gases, the overall efficiency of the engine and the exhaust gases flow rate. The model takes into account the possibility of using exhaust gas heat recirculation in order to enhance engine warm-up during cold start which improves its efficiency. The supervisory strategy takes into account not only predicted speed and ambient and road conditions along a future time window but also actual battery state of the charge and engine temperature to select the optimal power split between the ICE-generator group and the batteries. The proposed model represents an improvement with respect to a previous investigation of the authors where the temperature of the engine were assumed to increase/decrease of on Celsius degree in each seconds according to the state of the engine (ON/OFF).
Startup and Idle Emissions Analysis of a 2009 VW Jetta Using PEMS SemtechD
Authors: Johnson Michael V. , Duncan Samuel , McConnell Steven S.
Published: July 2013

A 2009 Volkswagen Jetta was tested using a Portable Emissions Measurement System (PEMS) SemtechD emissions analyzer to determine when the emissions and fuel consumption will be the smallest in regards to startup vs. idle emissions. An idle time equivalent was calculated to determine when idle emissions became equal to startup emissions at four different ambient temperatures for a cold start. The mass of Total Hydrocarbons (THC) emitted limited the idle time equivalent to less than the startup time for all ambient temperatures. The temperature of the Catalytic Converter (CC) was monitored to determine how quickly the car cools down and therefore, how beneficial it is to turn the car off after a certain time period. For the temperature range tested, it was more beneficial for reduced emissions to turn off the car compared to idling by a factor of at least four. The data suggests a trend that idling would never be the best option; however, more testing needs to be done with a greater range of CC cool down temperatures to confirm this initial assessment.
Performance and Exhaust Emission Characteristics of a Spark Ignition Engine Operated With Gasoline and CNG Blend
Authors: Dashti Mehrnoosh , Hamidi Ali Asghar , Mozafari Ali Asghar
Published: July 2013

Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption.

Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion.

In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the engine performance parameters and emission characteristics of CNG/gasoline blend fuelled engine. A spark ignition engine cycle simulation based on the first law of thermodynamic has been developed by stepwise calculations for compression process, ignition delay time, combustion and expansion processes. The building blocks of the model are mass and energy conservation equations. Newton-Raphson method has been used to solve the equations numerically and there was no need to solve them analytically. In the quasi-dimensional combustion model, the cylinder is divided into two zones separated by a thin flame front. The flame front propagates spherically throughout the combustion chamber to the point that it contacts the cylinder wall and head. The model effectively describes the thermodynamic processes and chemical state of the working fluid via a closed system containing compression, combustion, and expansion processes.

The model predicts the trends and tradeoffs the performance characteristics at various engine speeds. The variation of indicated power, ISFC and emissions are predicted by the model. Experimental data are also presented to indicate the validity of the model. The predicted results based on the model have shown reasonable agreement with the corresponding experimental data.
Modeling the Unsteady Flows in I.C. Engine Pipe Systems by Means of a Quasi-3D Approach
Authors: Montenegro G. , Della Torre A. , Cerri T. , Onorati A.
Published: July 2013

Increasing demands on the capabilities of engine simulation and the ability to accurately predict both performance and acoustics has lead to the development of several numerical tools to help engine manufacturers during the prototyping stage. One dimensional simulation tools are widely used during this phase and they allow the simulation of several engine configurations within a short time. Certain components, however, such as the intake and exhaust manifolds, exhibit a high degree of geometric complexity, which cannot be accurately modelled by ID codes, unless equivalent ID models are adopted. The need of achieving good accuracy, along with acceptable computational runtime, has given the spur to the development of a geometry based quasi-3D approach. This is designed to model the acoustics and the fluid dynamics of both intake and exhaust system components used in internal combustion engines. Models of components are built using a network, or grid, of quasi-3D cells based primarily on the geometry of the system. The solution procedure is an explicitly time marching pseudo staggered grid approach, where the equations of mass and energy are solved at cell centers while the momentum equation at cell connections or boundaries. The quasi-3D approach has been fully integrated into a ID research code in order to study the behavior of intake and exhaust devices under real engine pulsating flow conditions. This approach was mainly developed to model the acoustic behavior of complex shape silencers, however, in this work it has been extended and applied to the prediction of the fluid dynamic behavior of intake and exhaust systems. The validation was carried on a high performance V4 motorbike engine. In particular, the silencer and the air box have been modeled resorting to a quasi-3D reconstruction. Calculated results of instantaneous pressure traces and volumetric efficiency have been compared to measured data, highlighting a good capability in capturing dynamic effects with a computational runtime much lower than the one required by the integration of fully 3D models with the ID.
Diesel Particulate Filter Retrofit Screening Tests on a 1500 kW Gen Set Locomotive
Authors: Hedrick John , Fritz Steve , Jaczola Michael , Holmes Harold
Published: July 2013

One of the California Air Resources Board’s highest priorities is to reduce NOx and PM emissions from diesel engines. To support this goal, this project evaluated two different brands of experimental diesel particulate filters (DPF’s) on a 1,500 kW GenSet Switcher locomotives to determine their efficiency at reducing PM for this application. The locomotive used for these tests was UPY2737, an NREC Model 3GS-21B Ultra Low Emissions Locomotive (ULEL) originally manufactured in 2007. This is one of 70 of this type of locomotive operating in California. These locomotives are powered by three EPA Tier 3 nonroad, 522 kW, diesel engine driven generator sets.

Upon receipt, the locomotive was baseline emission tested and the results were provided to two DPF system suppliers. Experimental DPF’s provided by these suppliers were then installed and tested using only one of the three engine-gen sets.

The experimental DPF provided by Supplier “A” reduced PM emissions by 92 percent from baseline switch cycle levels, or 77 percent below the US EPA Tier 4 locomotive PM emission limit. Additionally this system essentially did not change the NOX emissions and cycle weighted fuel consumption from the engine. The experimental DPF provided by Supplier “B” also showed no significant change in the switch cycle weighted fuel consumption and NOX emission and reduced the PM emissions by 88 percent, which is 63 percent below the Tier 4 locomotive PM emissions limit.

Based on these successful screening test results, projects are underway to equip all three engines with production intent retrofit DPF systems on two revenue service locomotives, one for each of the two DPF suppliers.
Effects of Jatropha Curcas Oil and Alkyl Ester as Lubricity Enhancer for Diesel Fuel
Authors: Prasad Lalit , Das L. M. , Naik S. N.
Published: July 2013

Increasing strict regulation on the sulfur content of diesel fuels results in decreases the lubricity of these fuels. The lubricity of the fuel is an indication of the amount of wear or scarring that occurs between two metal parts covered with the fuel as they come in contact with each other. Low lubricity fuel may cause high wear and scarring and high lubricity fuel may provide reduced wear and longer component life. Previous studies have shown that alkyl esters of triglycerides derived from vegetable oils have increased diesel fuel lubricity at concentration of less than 1%. The major objective of this study was to analyze the effectiveness of indigenous non-edible feedstocks such as jatropha (Jatropha curcas) as an additive in petroleum based diesel fuels. Jatropha oil, and its alky esters (methyl and ethyl ester) and oil-ester blends with diesel were tested as an additive to enhance the lubricity of diesel fuels. In case of fuels, the lubricating behavior is associated with boundary film-forming properties. The analysis was carried out by using ASTM 6079-4 test method using High Frequency Reciprocating Rig (HFRR model D1377) as an analytical tool. The coefficient of friction and wear was observed higher for the low lubricity diesel fuel (LLDF) and it decreases with the addition of additive dose of oil, methyl and ethyl ester of jatropha. It may be due to the better lubricating behavior of non-edible based oil and ester compare to LLDF. During the HFRR test 2±0.20 ml of fluid sample under test is placed in reservoir which is maintained at a specified temperature of 60±2 °C. The HFRR test uses a vertically mounted steel ball to apply force to a horizontally mounted stationary steel disk with an applied load (200±1 g). The test ball is oscillated at a fixed frequency (50 ± 1 Hz) with a fixed stroke length (1 ± 0.02 mm) while the disk is fully immersed in the fluid reservoir. The whole test rig was placed in the humidity cabin with transparent enclosure. The test was kept for 75 minutes and the wear scar on the ball was measured by electronic microscope. It is believed that the high concentration of the particular fatty acid in oil and alkyl ester could be responsible for enhancing the lubricity and subsequent lower wear scar.
Understanding the Acoustic Oscillations Observed in the Injection Rate of a Common-Rail DI Diesel Injector
Authors: Manin Julien , Kastengren Alan , Payri Raul
Published: July 2013

Measuring the rate of injection of a common-rail injector is one of the first steps for diesel engine development. At the same time, this information is of prime interest for engine research and modeling as it drives spray development and mixing. On the other hand, the widely used long-tube method provides results that are neither straightforward, nor fully understood. This study performed on a 0.09 mm axially drilled single-hole nozzle is part of the Engine Combustion Network (ECN) and aims at analyzing these features from an acoustic point of view to separate their impact on the real injection process and on the results recorded by the experimental devices. Several tests have been carried out for this study including rate of injection and momentum, X-ray phase-contrast of the injector and needle motion or injector displacement. The acoustic analysis revealed that these fluctuations found their origin in the sac of the injector and that they were the results of an interaction between the fluid in the chamber (generally gases) and the liquid fuel to be injected. It has been observed that the relatively high oscillations recorded by the long-tube method were mainly caused by a displacement of the injector itself while injecting. In addition, the results showed that these acoustic features also appear on the momentum flux of the spray which means that the real rate of injection should present such behavior.
Further Research Into Wheel Rim Axial Residual Stress and Vertical Split Rim Failures
Authors: Lonsdale Cameron , Oliver John
Published: July 2013

Recent work using x-ray diffraction techniques has shown that the axial residual stress pattern within the railroad wheel rim is significantly different for as-manufactured AAR Class C wheels vs. AAR Class C wheels that have failed due to a vertical split rim (VSR), and non-failed AAR Class C wheels that have been operating in service. VSRs almost always begin at areas of tread damage, resulting from shelling or spalling, and cracking propagates into the rim section under load. At the locations tested, the as-manufactured wheels have a relatively “flat” axial residual stress profile, compressive but near neutral, caused by the rim quenching operation, while wheels that have been in service have a layer of high axial compressive stress at the tread surface, and a balancing zone of axial tensile stress underneath. The magnitude and direction of this tensile stress is consistent with the crack propagation of a VSR failure. When cracks from the tread surface propagate into this sub-surface axial tensile zone, a VSR can occur under sufficient additional service loading, such as loads caused by in-service wheel/rail impacts from tread damage. Further, softer Class U wheels, removed from service and tested, were found to have a balancing axial tensile stress layer that is deeper below the tread surface than that found in used Class C wheels.

This paper describes further efforts to characterize the axial residual stress present in failed VSR and used Class C wheels. Axial residual stress results are obtained near the initiation point of several VSR wheels using x-ray diffraction. Sub-surface axial residual stress patterns are also determined at points of high out-of-roundness for a group of wheels that were tested for TIR (total indicated runout) on the tread surface. Residual stress data and a photo are presented for a wheel rim slice containing a second VSR crack. Additionally, wheel rim ultrasonic testing data, collected by the wheel manufacturer when the wheels were new, are discussed for wheels that have failed due to VSRs and these data are compared to ultrasonic data for non-VSR wheels. Chemistry data are also compared. These data show that the driving force for VSRs is axial residual tensile stress, not a material cleanliness issue.
Integration of Railway Electronic Systems to Achieve Safety and Efficiency
Authors: Cothen Grady C.
Published: July 2013

The railroad industry, including its freight and passenger components, is at a critical crossroads. One path promises a continuation of individual innovations, conceived and priced to address sometimes narrow requirements without relation to larger needs. The other path is directed toward a more connected and effective approach, claiming individual benefits while also achieving synergies not obtainable using the first. This paper advocates an integrated approach, resisting the conventional wisdom presently attending most discussions of communications-based train control systems and electronic braking platforms. It urges a more robust response to the opportunities presently presented, taking into consideration both railroad profitability and the public interest. Appropriate consideration is given to the need for both private and public resources to be applied to achieving the resulting benefits.