The Challenges of Turbocharger Matching for North American Freight Locomotives

2019 ◽  
Author(s):  
Thomas Lavertu ◽  
Matthew Hart ◽  
Christopher Homison ◽  
Preeti Vaidya
Keyword(s):  
North American ◽  
Engine Performance ◽  
Ambient Air ◽  
Ambient Conditions ◽  
Efficient Operation ◽  
Engine Efficiency ◽  
Air Temperatures ◽  
Wide Range ◽  
The Impact ◽  
Operating Points

Abstract Engine development is centered on developing a solution for best performance while meeting emissions and operational requirements. This will lead to a tradeoff between engine efficiency and emissions across a wide range of load and ambient operating points. Proper airflow to the engine through turbocharger matching is critical to ensure efficient operation and to meet emissions. This study addresses the challenges of turbocharger matching for vehicle advanced emissions control using a North American freight locomotive application as an example. The airflow trends in moving across the various operating points will be shown along with the impact on both the turbocharger and engine performance. First, the airflow trends across the locomotive load set points will be discussed along with the performance and emissions tradeoffs to meet required airflows. Results on the impact on turbocharger performance such as speed will be shown along with the engine efficiency and emissions implications. Next, the ambient operating requirements for a locomotive will be reviewed and the impact on turbocharger matching. Locomotives operate in a wide range of ambient conditions, including altitudes up to 3,050 meters and across ambient air temperatures ranging from −40 °C to well over 38 °C (including higher temperature operation). This thermal swing provides stress on the turbocharger to efficiently deliver the necessary airflow across all conditions. Trends in turbocharger performance will be reviewed and discussed across this range of ambient conditions. In addition, challenges unique to locomotive applications, such as unventilated tunnel operation and vibrational loading, will be reviewed. Finally, potential for advanced technologies such as variable geometry turbines and their applicability to locomotive operation will be discussed.

Ambient Condition Effects on NOx and CO Emissions From Process Heaters

2008 ◽  
Author(s):  
Wesley R. Bussman ◽  
Charles E. Baukal
Keyword(s):  
Atmospheric Pressure ◽  
Ambient Air ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Fuel Gas ◽  
Natural Draft ◽  
Actual Operating ◽  
Wide Range ◽  
Pollution Emissions

Because process heaters are typically located outside, their operation is subject to the weather. Heaters are typically tuned at a given set of conditions; however, the actual operating conditions may vary dramatically from season to season and sometimes even within a given day. Wind, ambient air temperature, ambient air humidity, and atmospheric pressure can all significantly impact the O2 level, which impacts both the thermal efficiency and the pollution emissions from a process heater. Unfortunately, most natural draft process burners are manually controlled on an infrequent basis. This paper shows how changing ambient conditions can considerably impact both CO and NOx emissions if proper adjustments are not made as the ambient conditions change. Data will be presented for a wide range of operating conditions to show how much the CO and NOx emissions can be affected by changes in the ambient conditions for fuel gas fired natural draft process heaters, which are the most common type used in the hydrocarbon and petrochemical industries. Some type of automated burner control, which is virtually non-existent today in this application, is recommended to adjust for the variations in ambient conditions.

scholarly journals Impact of Transformer Turns Ratio on the Power Losses and Efficiency of the Wide Range Isolated Buck–Boost Converter for Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5645
Author(s):  
Hamed Mashinchi Maheri ◽  
Dmitri Vinnikov ◽  
Andrii Chub ◽  
Vadim Sidorov ◽  
Elizaveta Liivik
Keyword(s):  
High Efficiency ◽  
Input Voltage ◽  
Power Losses ◽  
Efficient Operation ◽  
Wide Range ◽  
Photovoltaic Applications ◽  
Theoretical Predictions ◽  
Converter Topology ◽  
Isolation Transformer ◽  
The Impact

In this paper, the impact of transformer turns ratio on the performance of the quasi-Z-source galvanically isolated DC-DC converters is studied. Embedded buck–boost functionality enables these converters to regulate the input voltage and load in a wide range, which makes them suitable for such demanding application as photovoltaic microconverters. The isolation transformer here plays a central role as its turns ratio defines the point of transition between the boost and buck modes and overall capability of the converter to regulate the input voltage in a wide range at high efficiency. The studied quasi-Z-source galvanically isolated DC-DC converter is benchmarked in terms of power loss of components and weighted power conversion efficiency for three different turns ratios of isolation transformer to achieve the best and optimized turns ratio lead to the efficient operation. Operation in a wide range of input voltage at high efficiency is the main criterion for assessing the effect of turns ratio on the efficiency of the converter. The proposed loss model and theoretical predictions of the efficiency were validated with the help of a 300 W experimental prototype of the photovoltaic microconverter based on the quasi-Z-source galvanically isolated DC-DC converter topology.

A Simplified Method to Evaluate the Impact of Component Design on Engine Performance

2007 ◽  
Author(s):  
Francesco Montella ◽  
J. P. van Buijtenen
Keyword(s):  
Design Process ◽  
Engine Performance ◽  
Simulation Software ◽  
Fast Method ◽  
Engine Simulation ◽  
Engine Model ◽  
Component Design ◽  
Wide Range ◽  
Engine Component ◽  
The Impact

This paper presents a simplified and fast method to evaluate the impact of a single engine component design on the overall performance. It consists of three steps. In the first step, an engine system model is developed using available data on existing engines. Alongside the cycle reference point, a sweep of operating points within the flight envelop is simulated. The engine model is tuned to match a wide range of conditions. In the second step, the module that contains the engine component of interest is analyzed. Different correlations between the component design and the module efficiency are investigated. In the third step, the deviations in efficiency related to different component configurations are implemented in the engine baseline model. Eventually, the effects on the performances are evaluated. The procedure is demonstrated for the case of a two-spool turbofan. The effects of tip leakage in the low pressure turbine on the overall engine performance are analyzed. In today’s collaborative engine development programs, the OEMs facilitate the design process by using advanced simulation software, in-house available technical correlations and experience. Suppliers of parts have a limited influence on the design of the components they are responsible for. This can be rectified by the proposed methodology and give subcontractors a deeper insight into the design process. It is based on commercially available PC engine simulation tools and provides a general understanding of the relations between component design and engine performance. These relations may also take into account of aspects like production technology and materials in component optimization.

Distributed Hydrologic Modeling in Northwest Mexico Reveals the Links between Runoff Mechanisms and Evapotranspiration

2012 ◽  
Vol 13 (3) ◽  
pp. 785-807 ◽  
Author(s):  
Agustín Robles-Morua ◽  
Enrique R. Vivoni ◽  
Alex S. Mayer
Keyword(s):  
North American ◽  
Land Surface ◽  
Temporal Variations ◽  
Hydrologic Model ◽  
Runoff Generation ◽  
Limited Region ◽  
The North ◽  
Wide Range ◽  
Infiltration Excess ◽  
The Impact

Abstract A distributed hydrologic model is used to evaluate how runoff mechanisms—including infiltration excess (RI), saturation excess (RS), and groundwater exfiltration (RG)—influence the generation of streamflow and evapotranspiration (ET) in a mountainous region under the influence of the North American monsoon (NAM). The study site, the upper Sonora River basin (~9350 km2) in Mexico, is characterized by a wide range of terrain, soil, and ecosystem conditions obtained from best available data sources. Three meteorological scenarios are compared to explore the impact of spatial and temporal variations of meteorological characteristics on land surface processes and to identify the value of North American Land Data Assimilation System (NLDAS) forcing products in the NAM region. The following scenarios are considered for a 1-yr period: 1) a sparse network of ground-based stations, 2) raw forcing products from NLDAS, and 3) NLDAS products adjusted using available station data. These scenarios are discussed in light of spatial distributions of precipitation, streamflow, and runoff mechanisms during annual, seasonal, and monthly periods. This study identified that the mode of runoff generation impacts seasonal relations between ET and soil moisture in the water-limited region. In addition, ET rates at annual and seasonal scales were related to the runoff mechanism proportions, with an increase in ET when RS was dominant and a decrease in ET when RI was more important. The partitioning of runoff mechanisms also helps explain the monthly progression of runoff ratios in these seasonally wet hydrologic systems. Understanding the complex interplay between seasonal responses of runoff mechanisms and evapotranspiration can yield information that is of interest to hydrologists and water managers.

Design relations for predicting surface-ice clearing capacity of open channels

2000 ◽  
Vol 27 (6) ◽  
pp. 1230-1239 ◽  
Author(s):  
I Morin ◽  
R D Townsend ◽  
B Morse
Keyword(s):  
Environmental Parameters ◽  
Operating Conditions ◽  
Water Current ◽  
Ambient Conditions ◽  
Navigation Channel ◽  
Wide Range ◽  
Ice Concentration ◽  
Wind Characteristics ◽  
Surface Ice ◽  
The Impact

Numerical simulations are performed to evaluate the impact of various hydraulic and environmental parameters on the ice clearing capacity of a Lac St-Pierre navigation channel. The Lagrangian particle-dynamics (Pdyn) model is used to simulate a wide range of "operating" conditions that are representative of conditions observed on Lac St-Pierre. Simple relationships are developed that express both ice velocity and flux as functions of the geometry of the channel (width and plan-form shape) and ambient conditions (ice concentration, thickness, water current, wind magnitude and direction). These relationships reflect the importance of wind characteristics and areal ice concentration in regard to predicting both surface ice velocities and flux.Key words: ice clearing, channel geometry, ambient conditions.

Two-Stage Turbocharging Solutions for Tier 4 Rail Applications

2015 ◽  
Author(s):  
Simone Bernasconi ◽  
Ennio Codan ◽  
David Yang ◽  
Pierre Jacoby ◽  
German Weisser
Keyword(s):  
Catalytic Reduction ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Ambient Conditions ◽  
Two Stage ◽  
Optimum Performance ◽  
Engine Model ◽  
High Fuel Efficiency ◽  
Wide Range ◽  
Turbocharging System

With the introduction of the EPA Tier 4 NOx emission limits for rail diesel engines this year, engine developers are forced to implement more advanced emission control technologies such as selective catalytic reduction (SCR) or cooled external exhaust gas recirculation (EGR). The integration and control of these systems for ensuring optimum performance throughout the operating range brings about new challenges on top of the well-known requirement for unconstrained operability in a very wide range of conditions. As a consequence, engines and their subsystems have to be designed for maximum flexibility. The turbocharging system in particular needs to be capable of dealing with extreme ambient conditions associated with high altitudes, hot summers, severe winters, tunnel operation, etc. This flexibility must be achieved without compromising reliability and while ensuring continuous in-use compliance with the emissions standards throughout the life of the installation. At the same time, engine performance should be maintained at the highest level possible. This study demonstrates that all of these targets can be met by combining two-stage turbocharging and EGR with suitable control elements. Two-stage turbocharging, which has become increasingly popular in other industry sectors due to its potential for improving the bsfc / NOx emissions trade-off when used in combination with correspondingly optimized valve actuation (Miller timing), is starting to be adopted also for rail applications. A variety of EGR concepts was proposed or put into practice over the past few years, and the most important or promising of these have been taken into consideration for this study. Extensive simulations of the resulting engine and turbocharging systems have been performed using ABB’s in-house simulation platform, based on a generic engine model that can be considered representative of the rail sector. It is shown that integration of EGR, two-stage turbocharging and appropriate control elements is highly attractive as it offers outstanding operational flexibility and very high fuel efficiency without any compromise in terms of reliability. The selection and specification of control elements and turbocharging system components depends on the EGR concept applied. As is shown below, this can be tailored to the application to ensure optimum performance and flexibility. In view of these obvious benefits, we are very confident that such integrated EGR / two-stage turbocharging systems will be adopted more widely on railway engines.

scholarly journals Effect of urban Morphology on Subtropical Humid Microclimate: the case of Bhopal, India

2019 ◽  
Vol 8 (3) ◽  
pp. 2376-2382
Keyword(s):  
Thermal Stress ◽  
Urban Areas ◽  
Central India ◽  
Ground Cover ◽  
Field Measurements ◽  
Ambient Air ◽  
Urban Morphology ◽  
Air Temperatures ◽  
New City ◽  
The Impact

In a humid subtropical atmosphere, urbanisation leads to increased thermal stress. The outside thermal stress depends on the flexibility of the geometrical arrangement of the buildings and its morphology and also materials to absorb solar radiation (albedo). The purpose of this study is to look at the influence of the morphology and water bodies on the microclimate of Bhopal, a town in central India. In this study the impact of urban morphology on microclimate is assessed through filed measurements. The field measurements included ambient air temperatures, humidity and wind speed. These metrological parameters were measured at nine sites in which three are in the old city, four in a new city and two sites falls in the suburbs. All three types of sites differed in terms of the building height by street width (H/W) ratio, ground cover, and distance to the lakes. In urban areas air high-temperature differences were mostly found during daytime. A highest intra-urban dissimilarity of 6ºC has been traced on clear days. Within the urban areas, the humidity was found normal (up to25-30%), and showed little diurnal variation. Few other factors that affected the temperature were also observed and are discussed in this paper

Plasma volume conservation in pigeons: effects of air temperature during dehydration

1994 ◽  
Vol 267 (6) ◽  
pp. R1449-R1453 ◽  
Author(s):  
N. Carmi ◽  
B. Pinshow ◽  
M. Horowitz
Keyword(s):  
Blood Cell ◽  
Air Temperature ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Total Body Water ◽  
Ambient Air ◽  
Columba Livia ◽  
Ambient Conditions ◽  
Air Temperatures ◽  
Total Body

We assessed the effects of the ambient air temperature prevailing during dehydration, which included complete water and food deprivation, on plasma volume (PV) conservation in pigeons (Columba livia) exposed to air temperatures of 25 degrees C (n = 7), 36 degrees C (n = 12), and 40 degrees C (n = 24). The pigeons were dehydrated for 65.4, 32.3, and 27.7 h, on average, at 25, 36, and 40 degrees C, respectively. Dehydration rates averaged 5, 10, and 15.2% of initial total body water (TBW) per day at the three air temperatures, in ascending order. Birds exposed to 25 and 36 degrees C maintained PV despite the fact that they lost, on average, 14 and 17.3% of their TBW, respectively. In contrast, PV in pigeons exposed to 40 degrees C decreased by 8.9%, even though the reduction in TBW (17.7%) was similar to that incurred at 36 degrees C. Mean plasma osmolalities reached 347.7, 345.6, and 374.8 mosmol/kgH2O at 25, 36, and 40 degrees C, respectively. No significant changes occurred in hematocrit (Hct) and hemoglobin concentrations (Hb) during dehydration at 25 and 36 degrees C. However, at 40 degrees C Hb increased by 8.2% with no change in Hct, indicating a decrease in red blood cell volume (RBCV). The results of this study suggest that maintenance of PV and RBCV is affected not only by the dehydration level attained but also by the ambient conditions under which dehydration is induced and the rate at which dehydration takes place.

scholarly journals Spatio-Temporal Variation in the Concentration of Inhalable Particulate Matter (PM10) in Uganda

2019 ◽  
Vol 16 (10) ◽  
pp. 1752 ◽  
Author(s):  
Silver Onyango ◽  
Beth Parks ◽  
Simon Anguma ◽  
Qingyu Meng
Keyword(s):  
Particulate Matter ◽  
Sampling Period ◽  
Ambient Air ◽  
Average Density ◽  
Diurnal Variations ◽  
Time Data ◽  
Seasonal Differences ◽  
Wide Range ◽  
The Impact

Long-term particulate matter (PM10) measurements were conducted during the period January 2016 to September 2017 at three sites in Uganda (Mbarara, Kyebando, and Rubindi) representing a wide range of urbanization. Spatial, temporal and diurnal variations are assessed in this paper. Particulate matter (PM10) samples were collected for 24-h periods on PTFE filters using a calibrated pump and analyzed gravimetrically to determine the average density. Particulate levels were monitored simultaneously using a light scattering instrument to acquire real time data from which diurnal variations were assessed. The PM10 levels averaged over the sampling period at Mbarara, Kyebando, and Rubindi were 5.8, 8.4, and 6.5 times higher than the WHO annual air quality guideline of 20 µg·m−3, and values exceeded the 24-h mean PM10 guideline of 50 µg·m−3 on 83, 100, and 86% of the sampling days. Higher concentrations were observed during dry seasons at all sites. Seasonal differences were statistically significant at Rubindi and Kyebando. Bimodal peaks were observed in the diurnal analysis with higher morning peaks at Mbarara and Kyebando, which points to the impact of traffic sources, while the higher evening peak at Rubindi points to the influence of dust suspension, roadside cooking and open-air waste burning. Long-term measurement showed unhealthy ambient air in all three locations tested in Uganda, with significant spatial and seasonal differences.

scholarly journals The Use of Enhanced Nozzle Maps for Gas-Turbine Performance Modelling

2021 ◽  
Author(s):  
Aws A. Al-Akam ◽  
Theoklis Nikolaidis ◽  
David G. MacManus ◽  
Alvise Pellegrini
Keyword(s):  
Three Dimensional ◽  
Flow Characteristics ◽  
Engine Performance ◽  
Exhaust System ◽  
Limited Range ◽  
Performance Modelling ◽  
Essential Components ◽  
Wide Range ◽  
Aero Engine ◽  
The Impact

Abstract The use of a simulation tool to predict the aero-engine performance before committing to a final engine design has become one of the most cost-saving approaches in this field. However, most of these tools are based on low fidelity thermodynamic models, which are incapable of fully capturing the impact of three-dimensional flow characteristics. An aero-engine exhaust-system is one of the essential components that affect the engine performance. Currently, engine performance models tend to utilize simplified nozzle performance maps. These maps typically provide information over a very limited range of nozzle geometries, which may not apply to the wide range of architectures and designs of aeroengines. The current paper presents a methodology for the development of nozzle performance maps, which takes into account the aerodynamic and the geometric parameters of the nozzle design. The methodology is based on the reduced-order models. These models are integrated into a zero-dimensional engine performance code to improve the accuracy of its thrust calculation. The impact of the new thrust model on the overall engine performance and the operating point is analysed and discussed. The results showed that the implementation of the modified maps, which take into account the flow characteristics and the geometry of the nozzle, affects the thrust calculation. In a typical case of a turbofan operating at cruise conditions, the net thrust estimation with the modified nozzle maps showed a difference of 0.2%, compared with the simple nozzle maps. The new thrust calculation method has the advantage in capturing the multidimensional impact of the flow of the nozzle as compared with the conventional one. Furthermore, the implementation of the new method reduces the uncertainties introduced by a simplified nozzle model and, consequently, it can support the decision-making process in the design of the engine.

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