bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of In-Cylinder Friction Using the Floating Liner Principle
Authors: Gore M. , Howell-Smith S. J. , King P. D. , Rahnejat H. 
Published: July 2013

The regime of lubrication changes in a transient manner in many load bearing conjunctions. This is particularly true of any conjunction which is subjected to changes in contact kinematics as the result of stop-start or motion reversals and loading. One such conjunction in the IC engine is the piston-bore contact. A repercussion of these transient events under otherwise perceived steady operating condition is the underlying changes in the mechanisms giving rise to engine efficiency, such as parasitic losses, mainly due to friction. Understanding the nature of these losses is the prelude to any form of palliation.
A single cylinder motocross motorbike engine’s cylinder barrel is redesigned to accept wet liners with various incorporated instrumentation. The paper describes one such barrel which incorporates an instrumented floating liner for the purpose of measurement of in-cylinder friction. The principle and design of the floating liner is described. A series of tests are carried out in order to ensure the operational integrity and repeatability of the device. The basic test includes motorised running of the engine without the cylinder head installed. This renders simplified motion of the liner, subject to resistance by friction only. In a sense, under this type of motion, the liner should undergo a form of simple harmonic motion, which is verified using a number of suitably positioned accelerometers.
Some more representative tests are reported under motorised conditions with the cylinder head installed. Thus, the effect of chamber pressure is introduced. However, with no combustion pressure, heat output and resulting side forces, a better understanding of tribological conditions is accrued owing to the reduced physical interactions. The results show the dominance of a mixed regime of lubrication at the dead centre reversals.
Effect of Hydrogen and CO Addition, Produced Through POM (Partial Oxidation of Methane) on a CHP Gas Engine
Authors: Saikaly Khalil , Criner-Thai Karine , Mati Karim 
Published: July 2013

This article presents a summary of some experimental results obtained on a 1.4 MW CHP engine. Tests concern the effect of H2 and CO addition to the natural gas at the engine inlet. Hydrogen and CO were obtained through the partial oxidation of methane.
A honey-comb Platinum based catalyst was used for the partial oxidisation of methane. Part of the natural gas main stream was deviated and mixed with air to supply the catalyst. Catalyst output (mixture of H2, CO, H2O, CO2, N2 and methane) are then mixed with the main stream of natural gas supplying the engine.
Two different tests were conducted, the first one is an operation under a constant average combustion chamber temperature and the other one is an operation at a constant NOX level in the exhaust gases.
Results showed a decrease of about 10% in NOX emissions when operating under constant combustion chamber temperature (this temperature is the average temperature of the four strokes inside the cylinders); and a slight increase of engine efficiency for a constant NOX emissions level.
NOx Reduction Potential of Dedicated Cylinders for an EMD 2-Stroke Model 710 Diesel Engine
Authors: Uzkan Teoman , Moravec Keith E. , Heilenbach James W. 
Published: July 2013

To satisfy the Tier-4 requirements EMD as well as other large engine manufacturers are investigating the emission reduction potentials of different technologies whether they are application ready or in concept stage. One of the recent trends is to use dedicated cylinders as EGR gas suppliers. In this study the NOx reduction potential of dedicated cylinders for the two-cycle EMD 16-710 engine is evaluated analytically.
The performance of the well known and documented 16-710 T-2 engine is chosen as the base case. An analytical model is developed to simulate the engine operation by using the commercially available GT-Power code. Model parameters are adjusted to fit predictions to test data.
The base model is then modified for a high pressure cooled EGR system. The system parameters are changed to optimize the system for selected criteria. Predicted performance of the system is compared against the base case.
The system model with EGR is further modified to accommodate the use of dedicated cylinders as the gas supplier to the EGR loop. The following dedicated cylinder variables are changed to optimize the system performance for NOx reductions; (a). Number of dedicated cylinders, (b). Location of dedicated cylinders, (c). Dedicated cylinder’s flow rate (EGR rate), (d). Compression ratio, (e). Injection timing, (f). Valve timing, (g). Valve lift profile, (h). Valve opening and closing times. Predicted results are compared against cases with and without EGR.
The study demonstrates that a 3-cylinder dedicated system, supplying the EGR gases, has the potential to reduce the tailpipe BSNOx below Tier-4 emissions level at Notch 8 operation condition of the engine. The study also suggests that designing the dedicated cylinders as if they are a different engine, for BHP while designing the normal cylinders to reduce BSNOx can be a successful strategy.
During this study the basic mechanisms of EGR in reducing the engine NOx is classified into three groups. It is shown that the Flow Diversion Effect of EGR can be above 40% of total BSNOx reduction.
The Abnormal Combustion Affected by Lubricating Oil Ignition in Premixed Gas Engine
Authors: Yasueda Shinji , Takasaki Koji , Tajima Hiroshi 
Published: July 2013

The thermal efficiency of gas engines have been improved considerably in the last decade and now some of gas engines has achieved higher efficiency than diesel engines by introducing the state of the arts technologies. But at the same time, the abnormal combustion with the high peak firing pressure has been seen in recent years especially on high BMEP engines. This combustion has the unique characteristics such that it occurs temporally with the limited crank angle of advanced timing and the retarded spark ignition timing makes it worse.
As the results of researches including the visualization tests on the single cylinder engine, this combustion was confirmed to be the kind of pre-ignition caused by the auto ignition of in-cylinder lubricating oil. And it was found to be one of the causes of the cyclic variation of peak firing pressure on premixed combustion gas engine.
The lubricating oil can be ignited in the cylinder near the end of compression stroke where the temperature in cylinder is high enough for fuel oil to ignite. This is a natural phenomenon because the auto ignition temperature of lubricating oil is same level as that of fuel oil. But this phenomenon has not been considered so deeply so far because it has not caused serious combustion problems. But from now, more careful design by adding the view of the abnormal combustion caused by lubricating oil will be required for the future engines having the higher BEMP and thermal efficiency. Especially in case of gas engine ignited by fuel oil, such as Micro Pilot and Dual Fuel engine, the stable combustion window where combustion can be initiated and controlled not by lubricating oil but by fuel oil will become narrow.
In this paper, the characteristics of this abnormal combustion on production engines and the visualization data of combustions measured on a test engine are introduced and then the consideration about the mechanism and the analysis of this phenomenon are described in detail.
Assessment of Friction for Cam-Roller Follower Valve Train System Subjected to Mixed Non-Newtonian Regime of Lubrication
Authors: Turturro A. , Rahmani R. , Rahnejat H. , Delprete C. , Magro L. 
Published: July 2013

The tribology of cam-roller follower conjunction is highly dependent on the engine type and working conditions. The interface experiences transient conditions due to variations in contact geometry and kinematics, as well as loading. These lead to instantaneous and capricious behavior of the lubricant through the contact, which determines the regime of lubrication. The resulting frictional characteristics are affected by the shear of the lubricant film and the interaction of rough surfaces themselves. Thus, specific analysis is required for any intended new engine configuration. Therefore, a tribo-dynamic model, combining valve train dynamics, contact kinematics and tribological analysis is required. An important issue is to develop a simple yet reliable and representative model to address the above mentioned pertinent issues. This would make for rapid scenario-building simulations which are critical in industrial design time-scales.
The current model has been developed in response to the above mentioned requirements. A multi-body dynamic model for the valve train system based on the key design parameters is developed and integrated with an EHL tribological model for the cam-follower contact. To keep the model simple and easy to use and to avoid time-consuming computations, the analytical EHL model makes use of Grubin’s oil film thickness equation. Viscous and boundary contributions to friction are obtained as these account for the losses which adversely affect the engine fuel efficiency.
Actual Tip Layout and Off-Axis Stroke in Nozzle Flow Modeling Under Ballistic Needle Displacement
Authors: Chiatti Giancarlo , Palmieri Fulvio 
Published: July 2013

The injection of small amount of diesel fuel is mainly achieved through the shortening of energizing signal. Consequently, in such injection phases, the needle does not reach the mechanical stroke-end and its displacement may be defined as ballistic.
By means of a detailed 3D-CFD modeling, the behavior of nozzle flow is investigated under typical pilot/split injection conditions, namely high injection pressure and low needle lift. The investigation focuses on the effects of the restricted flow passage on fuel flow at hole inlets. Once the modeling details are described, the influence of different elements on the internal fuel flow is shown and discussed, pointing out the role of different driving factors; investigations take into account actual injector tip layouts and the response to the needle off-axis operating conditions. Results are presented highlighting the flow pattern features within the nozzle and their reflects on the hole-to-hole differences.
Reducing Emissions From Diesel-Hauled Commuter Trains by Recouping Braking Energy
Authors: Eggleton Peter 
Published: July 2013

The concept of a hybrid braking energy recoupment system was defined for coaches of diesel-hauled regional commuter trains. Functional specifications were developed having the goal of increasing by 25 percent the acceleration rate of a commuter train consisting of 10 bi-level coaches hauled by a 3,000 hp diesel locomotive, typical of the rolling stock now in service in Canada and the U.S.A. Because increasing train acceleration was the primary aim, the concept was named the Hybrid Augmented Traction System (HATS). Analyses of HATS simulations showed that in addition to augmenting acceleration and reducing trip time, braking energy recoupment reduced fuel consumption and corresponding diesel emissions.
Examined were three alternate hybrid systems for train retardation by recoupment of braking energy, its storage and then regeneration based, respectively, on Hydrostatic, Battery and Ultracapacitor energy storage. The Ultracapacitor Hybrid system appeared the most promising due to the capability of ultracapacitors to repeatedly and rapidly accept large charges, be temperature insensitive and flexible in the placement of modules in the limited space available. The study foresees that HATS technology development could be expedited via the procurement process if railway operators specified braking energy recoupment requirements in calls-for-proposals for new capital equipment.
Combustion Noise Real-Time Evaluation and Processing for Combustion Control
Authors: Ponti Fabrizio , Ravaglioli Vittorio , Moro Davide , De Cesare Matteo 
Published: July 2013

Newly developed Diesel engine control strategies are mainly aimed at pollutant emissions reduction, due to the increasing request for engine-out emissions and fuel consumption reduction. In order to reduce engine-out emissions, the development of closed-loop combustion control algorithms has become crucial. Modern closed-loop combustion control strategies are characterized by two main aspects: the use of high EGR rates (the goal being to obtain highly premixed combustions) and the control of the center of combustion. In order to achieve the target center of combustion, conventional combustion control algorithms correct the measured value by varying Main injection timing.
It is possible to obtain a further reduction in pollutant emissions through a proper variation of the injection parameters. Modern Diesel engine injection systems allow designing injection patterns with many degrees of freedom, due to the large number of tuneable injection parameters (such as start and duration of each injection). Each injection parameter’s variation causes variations in the whole combustion process and, consequently, in pollutant emissions production. Injection parameters variations have a strong influence on other quantities that are related to combustion process effectiveness, such as noise radiated by the engine. This work presents a methodology that allows real-time evaluating combustion noise on-board a vehicle. The radiated noise can be evaluated through a proper in-cylinder pressure signal processing. Even though in-cylinder pressure sensor on-board installation is still uncommon, it is believed that in-cylinder pressure measurements will be regularly available on-board thanks to the newly developed piezo-resistive sensors.
In order to set-up the methodology, several experimental tests have been performed on a 1.3 liter Diesel engine mounted in a test cell. The engine was run, in each operating condition, both activating and deactivating pre-injections, since pre-injections omission usually produces a decrease in pollutant emissions production (especially in particulate matter) and a simultaneous increase in engine noise. The investigation of the correlation between combustion process and engine noise can be used to set up a closed-loop algorithm for optimal combustion control based on engine noise prediction.
Large Particles in Modern Diesel Engine Exhaust
Authors: Hoard John , Chafekar Tejas , Abarham Mehdi , Schwader Riley , Upplegger Steven , Styles Dan 
Published: July 2013

During research on diesel engine EGR cooler fouling a test stand giving visual access to the building deposit layer has been developed. Initial experiments reveal the presence of large particles in the exhaust. While conventional wisdom is that diesel particulates typically have log-normal size distributions ranging approximately 10–200 nm, the tests reported here observe small numbers of particles with sizes on the order of tens of μm. Such particles are not generally reported in the literature because exhaust particle sizing instruments typically have inertial separators to remove particles larger than ∼1 μm in order to avoid fouling of the nanoparticle measurement system.
The test stand provides exhaust or heated air flow over a cooled surface with Reynolds number, pressure, and surface temperature typical of an EGR cooler. A window allows observation using a digital microscope camera. Starting from a clean surface, a rapid build of a deposit layer is observed. A few large particles are observed. These may land on the surface and remain for long times, although occasionally a particle blows away.
In order to study these particles further, an exhaust sample was passed over a fiberglass filter, and the resulting filtered particles were analyzed. Samples were taken at the engine EGR passage, and also in the test stand tubing just before the visualization fixture. The resulting images indicate that the particles are not artifacts of the test system, but rather are present in engine exhaust.
MATLAB routines were developed to analyze the filter images taken on the microscope camera. Particles were identified, counted, and sized by the software.
It is not possible to take isokinetic samples and give quantitative measurement of the number and size distribution of the particles because the particles are large enough that inertial and gravitational effects will cause them to at least partially settle out of the flows. Nonetheless, the presence of particles tens of μm is documented.
Such particles are probably the result of in-cylinder and exhaust pipe deposits flaking. While these larger particles would be captured by the diesel particulate filter (DPF), they can affect intake and exhaust valve seating, EGR cooler fouling, EGR valve sealing, and other factors.
Individual and Synergistic Effects of Lubricant Additive Components on Diesel Particulate Filter Ash Accumulation and Performance
Authors: Sappok Alexander , Munnis Sean , Wong Victor W. 
Published: July 2013

The current CJ-4 oil specification places a limit on the oil’s sulfated ash content of 1.0% to reduce the build-up of lubricant-derived ash in the diesel particulate filter (DPF). Lubricant additives, specifically detergents and anti-wear additives, contribute to most of the sulfated ash content in the oil and ash accumulation in the DPF, and hence are studied with increasing interest in the optimization of the combined engine-oil-aftertreatment system. However, characteristics of ash deposits found in the particulate filter, which are affected by a number of parameters, differ markedly from those of the ASTM-method defined sulfated ash. In addition, ash characteristics and effects on DPF performance vary substantially among the different metallic base in the additives, specifically calcium, magnesium, and zinc. Through a series of carefully-controlled tests with specially-formulated lubricant additives, this work quantified the individual and combined effects of the most common detergent and anti-wear additives on the ash properties which directly influence DPF pressure drop.
The results show that different lubricant additive formulations (Ca, Zn, Mg) produce profound differences in DPF pressure drop. It was found that DPF ash is a complex mixture of metals (Ca, Zn, Mg) in the form of sulfates, phosphates, and oxides. These ash compounds each have unique physical properties, which affect DPF pressure drop differently. In particular, ash containing calcium sulfate compounds resulted in an increase in filter pressure drop by over a factor of two, relative to the same amount of ash composed only of zinc phosphate or magnesium oxide compounds, at the same ash loading in the DPF. In addition, synergistic effects due to specific additive combinations were also explored and showed significant differences in ash composition and degree of exhaust flow restriction imposed by the ash resulting from specific additive combinations, as opposed to the individual additives themselves. Results are useful not only for lubricant formulators to design oils for improved aftertreatment system compatibility, but also to understand the practical effects of ash in the DPF in relation to the standardized sulfated ash definition in the lubricant specification.
Design of Flangeway Gap for Restraining Rail
Authors: Hasan Nazmul 
Published: July 2013

The aim of the paper is to classify restraining rail, discuss the advantages and disadvantages of each type of restraining rail, derive the formula to determine the flangeway gap, and finally, to suggest a type of restraining rail for use. Three types of restraining rail are classified as:
1. Active restraining rail: Defined as the restraining rail that reduces the angle of attack (AOA) by more than 50%.
2. Semi-active restraining rail: Defined as the restraining rail that reduces the AOA by 50% or less, preferably between 40% ∼ 50%.
3. Passive restraining rail: Defined as the restraining rail that does not reduce the AOA. In other words, it plays a passive role in steering the wheel.
A design procedure is established to estimate the flangeway gap. The advantages and disadvantages of each type of restraining rail are discussed from design, maintenance, and functional points of view. The issue of optimization of the rail/wheel profile is also discussed in context with the presence of restraining rail.
One component of the flangeway gap is the space required for the angularity of the wheel. 2D CAD drawings are not efficient for this purpose, as the drawings cannot consider the AOA and the height of restraining rail on top of the rail level.
In this context, Nytram plot is a solution; however, the plot needs a number of sectional drawings at gauge point level, rail level, and the top-of-restraining-rail level from the 3D drawing. A mathematical model that counts both the AOA and the height of restraining rail from the top of the rail level is developed here to capture the essence of the Nytram plot, and thereby to assess the space required for the angularity of the wheel. Finally, a semi-active restraining rail, with a formula for flangeway gap, is suggested for use. Being less elaborate and less time consuming, the formula is easier and quicker than the Nytram plot to estimate flangeway gap. Moreover, one can quickly assess the effect of wheel size, the height of the restraining rail from the top of rail, and the radius of the curve on the flangeway gap.