Turbocharged CNG Engines for Urban Transportation: Evaluation of Turbolag Reduction Strategies by Means of Computational Analyses

2009 ◽  
Author(s):  
Mirko Baratta ◽  
Ezio Spessa
Keyword(s):  
Public Transportation ◽  
High Performance ◽  
Exhaust Valve ◽  
Liquid Fuels ◽  
Transient Condition ◽  
Specific Reference ◽  
Engine Model ◽  
Spark Timing ◽  
Pollutant Reduction ◽  
1D Numerical Simulation

Nowadays, many urban buses for public transportation are fuelled by compressed natural gas (CNG), due to its potential for energy saving and pollutant reduction, with specific reference to particulate matter emissions. However, turbocharging is required to recover the gaseous-fuel related power gap with respect to more traditional engines running on liquid fuels. Therefore, turbolag reduction is fundamental to achieve high performance during engine transients. Significant support for the study of turbocharged CNG engines and guidelines for the turbomatching process can be provided by 1D numerical simulation tools. In this paper, the topic of turbolag reduction is analyzed, and different strategies, namely, Early-Exhaust Valve Opening-Variable Valve Actuation (E-EVO-VVA) and spark timing control for combustion retard (ComR), are analyzed by means of a specifically developed and calibrated GT-POWER® engine model. Tip-in maneuvers in which the engine was coupled to a torque hydraulic converter under stall conditions were investigated, so as to reproduce a typical load transient condition for an urban bus accelerating from engine idle. The best improvement of turbolag was obtained by combining E-EVO-VVA and ComR, with a reduction of turbolag ranging from 60% to 70%. When a limit on the incylinder pressure is introduced, in order to prevent excessive exhaust valve mechanical stresses, the higher achievable reduction in turbolag was found to be between 35% and 45%.

scholarly journals Production Cost and Carbon Footprint of Biomass-Derived Dimethylcyclooctane as a High Performance Jet Fuel Blendstock

2021 ◽  
Author(s):  
Nawa Raj Baral ◽  
Minliang Yang ◽  
Benjamin G. Harvey ◽  
Blake A Simmons ◽  
Aindrila Mukhopadhyay ◽  
...  
Keyword(s):  
Production Cost ◽  
High Performance ◽  
Jet Fuel ◽  
Liquid Fuels ◽  
Jet Fuels ◽  
Selling Price ◽  
Low Carbon ◽  
Hydrogenation Catalysts ◽  
Raney Nickel Catalyst ◽  
Biomass Sorghum

<div> <div> <div> <p>Near-term decarbonization of aviation requires energy-dense, renewable liquid fuels. Biomass- derived 1,4-dimethylcyclooctane (DMCO), a cyclic alkane with a volumetric net heat of combustion up to 9.2% higher than Jet-A, has the potential to serve as a low-carbon, high- performance jet fuel blendstock that may enable paraffinic bio-jet fuels to operate without aromatic compounds. DMCO can be produced from bio-derived isoprenol (3-methyl-3-buten-1- ol) through a multi-step upgrading process. This study presents detailed process configurations for DMCO production to estimate the minimum selling price and life-cycle greenhouse gas (GHG) footprint considering three different hydrogenation catalysts and two bioconversion pathways. The platinum-based catalyst offers the lowest production cost and GHG footprint of $9.0/L-Jet-Aeq and 61.4 gCO2e/MJ, given the current state of technology. However, when the conversion process is optimized, hydrogenation with a Raney nickel catalyst is preferable, resulting in a $1.5/L-Jet-Aeq cost and 18.3 gCO2e/MJ GHG footprint if biomass sorghum is the feedstock. This price point requires dramatic improvements, including 28 metric-ton/ha sorghum yield and 95-98% of the theoretical maximum conversion of biomass-to-sugars, sugars-to-isoprenol, isoprenol-to-isoprene, and isoprene-to-DMCO. Because increased gravimetric energy density of jet fuels translates to reduced aircraft weight, DMCO also has the potential to improve aircraft efficiency, particularly on long-haul flights. </p> </div> </div> </div>

scholarly journals Masivo: Parallel Simulation Model Based on OpenCL for Massive Public Transportation Systems’ Routes

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1501
Author(s):  
Juan Ruiz-Rosero ◽  
Gustavo Ramirez-Gonzalez ◽  
Rahul Khanna
Keyword(s):  
Simulation Model ◽  
Transport System ◽  
Public Transport ◽  
Public Transportation ◽  
High Performance ◽  
Simulation Models ◽  
Transportation Systems ◽  
Transport Systems ◽  
Public Transport System ◽  
Speed Up

There is a large number of tools for the simulation of traffic and routes in public transport systems. These use different simulation models (macroscopic, microscopic, and mesoscopic). Unfortunately, these simulation tools are limited when simulating a complete public transport system, which includes all its buses and routes (up to 270 for the London Underground). The processing times for these type of simulations increase in an unmanageable way since all the relevant variables that are required to simulate consistently and reliably the system behavior must be included. In this paper, we present a new simulation model for public transport routes’ simulation called Masivo. It runs the public transport stops’ operations in OpenCL work items concurrently, using a multi-core high performance platform. The performance results of Masivo show a speed-up factor of 10.2 compared with the simulator model running with one compute unit and a speed-up factor of 278 times faster than the validation simulator. The real-time factor achieved was 3050 times faster than the 10 h simulated duration, for a public transport system of 300 stops, 2400 buses, and 456,997 passengers.

Novel process and catalytic materials for converting CO2 and H2 containing mixtures to liquid fuels and chemicals

2015 ◽  
Vol 183 ◽  
pp. 197-215 ◽  
Author(s):  
Nora Meiri ◽  
Yakov Dinburg ◽  
Meital Amoyal ◽  
Viatcheslav Koukouliev ◽  
Roxana Vidruk Nehemya ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
High Performance ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Reactor System ◽  
Liquid Fuels ◽  
High Productivity ◽  
Carbide Phases ◽  
Production Of Hydrogen ◽  
Higher Hydrocarbons

Carbon dioxide and water are renewable and the most abundant feedstocks for the production of chemicals and fungible fuels. However, the current technologies for production of hydrogen from water are not competitive. Therefore, reacting carbon dioxide with hydrogen is not economically viable in the near future. Other alternatives include natural gas, biogas or biomass for the production of carbon dioxide, hydrogen and carbon monoxide mixtures that react to yield chemicals and fungible fuels. The latter process requires a high performance catalyst that enhances the reverse water-gas-shift (RWGS) reaction and Fischer–Tropsch synthesis (FTS) to higher hydrocarbons combined with an optimal reactor system. Important aspects of a novel catalyst, based on a Fe spinel and three-reactor system developed for this purpose published in our recent paper and patent, were investigated in this study. Potassium was found to be a key promoter that improves the reaction rates of the RWGS and FTS and increases the selectivity of higher hydrocarbons while producing mostly olefins. It changed the texture of the catalyst, stabilized the Fe–Al–O spinel, thus preventing decomposition into Fe3O4 and Al2O3. Potassium also increased the content of Fe5C2 while shifting Fe in the oxide and carbide phases to a more reduced state. In addition, it increased the relative exposure of carbide iron on the catalysts surface, the CO2 adsorption and the adsorption strength. A detailed kinetic model of the RWGS, FTS and methanation reactions was developed for the Fe spinel catalyst based on extensive experimental data measured over a range of operating conditions. Significant oligomerization activity of the catalyst was found. Testing the pelletized catalyst with CO2, CO and H2 mixtures over a range of operating conditions demonstrated its high productivity to higher hydrocarbons. The composition of the liquid (C5+) was found to be a function of the potassium content and the composition of the feedstock.

Multi-Cycle Simulation of the Mixture Formation Process of an High Performance Engine at Part Load Condition

2012 ◽  
Author(s):  
Claudio Forte ◽  
Gian Marco Bianchi ◽  
Enrico Corti ◽  
Stefano Fantoni
Keyword(s):  
High Performance ◽  
Load Condition ◽  
Experimental Tests ◽  
Fuel Mixture ◽  
Critical Issue ◽  
Transient Condition ◽  
Mixture Formation ◽  
Part Load ◽  
Cycle Simulation ◽  
Load Conditions

Transient operation of engines leads to air fuel (A/F) ratio excursions, which can increase engine emissions. These excursions have been attributed to the formation of fuel films in the intake port, which are caused by a portion of the intake fuel impinging and adhering on the relatively cool port surface. These films act as a source or sink which cause the AF variations depending upon the transient condition. Gaining a fundamental understanding of the nature and quantity of such films may assist in future fuel mixture preparation designs that could aid in emission reductions, yet would not require overly expensive nor complicated systems. The control of air to fuel ratio is a critical issue for high performance engines: due to the low stroke-to-bore ratio the maximum power is reached at very high regimes, letting little time to the fuel to evaporate and mix with air. The injector located upstream the throttle causes a lot of fuel to impinge the throttle and intake duct walls, slowing the dynamics of mixture formation in part load conditions. The aim of this work is to present a CFD methodology for the evaluation of mixture formation dynamics applied to a Ducati high performance engine under part load conditions. The phenomena involved in the process are highly heterogeneous, and particular care must be taken to the choice of CFD models and their validation. In the present work all the main models involved in the simulations are validated against experimental tests available in the literature, selected based on the similarity of physical conditions of those of the engine configuration under analysis. The multi-cycle simulation methodology here presented reveals to be a useful tool for the evaluation of the mixture dynamics and for the evaluation of injection wall film compensator models.

Fuel Flexible Distributed Combustion for Gas Turbine Engines

2012 ◽  
Author(s):  
Ahmed E. E. Khalil ◽  
Ashwani K. Gupta
Keyword(s):  
Gas Turbine ◽  
High Performance ◽  
Low Noise ◽  
Liquid Fuels ◽  
Low Emission ◽  
Wide Range ◽  
Efficient Combustion ◽  
Pollutants Emission ◽  
Significant Performance ◽  
Reduction Of Nox

Distributed Combustion provides significant performance improvement of gas turbine combustors including uniform thermal field in the entire combustion chamber (improved pattern factor), ultra low emission of NOx and CO, low noise, enhanced stability and higher efficiency. Distributed combustion with swirl have been investigated to determine the beneficial aspects of such flows on clean and efficient combustion under simulated gas turbine combustion conditions with close focus on NOx emission. Near Zero emissions of NO and CO have been demonstrated using methane under distributed combustion conditions with heat release intensities commensurable to gas turbine applications. In this paper, distributed combustion is further investigated using both gaseous and liquid fuels with emphasis on pollutants emission and combustor performance with each fuel. Performance evaluation with the different fuels is established to outline the flexibility of the combustor in handling a wide range of fuels with different calorific values and phases with focus on ultra-low pollutants emission. Results obtained on pollutants emission and OH* chemiluminescence for the specific fuels examined at various equivalence ratios are presented. Near distributed combustion conditions with less than 5 PPM of NO emission were demonstrated under novel premixed conditions for the various fuels tested thus outlining the combustor ability to handle different fuels with high performance. Further reduction of NOx can be made with true distributed combustion condition.

Mean Value Engine Model Including Spark Timing for Powertrain Control Application

2013 ◽  
Author(s):  
Hadi Adibi Asl ◽  
Mohammadreza Saeedi ◽  
Roydon Fraser ◽  
Paul Goossens ◽  
John McPhee
Keyword(s):  
Mean Value ◽  
Powertrain Control ◽  
Engine Model ◽  
Spark Timing ◽  
Control Application

Capillary zone electrophoresis for haemoglobinopathy diagnosis

2012 ◽  
Vol 66 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Nicole Borbely ◽  
Lorraine Phelan ◽  
Richard Szydlo ◽  
Barbara Bain
Keyword(s):  
Capillary Electrophoresis ◽  
Capillary Zone Electrophoresis ◽  
High Performance ◽  
Reference Range ◽  
Specific Reference ◽  
Specific Method ◽  
Alkaline Ph ◽  
Zone Electrophoresis ◽  
Microcolumn Chromatography ◽  
Capillary Zone

AimsCapillary zone electrophoresis (CE) at alkaline pH is increasingly used in haemoglobinopathy diagnosis. We report our evaluation of automated CE, using the Capillarys 2 Flex Piercing instrument, as a routine diagnostic method for the detection of variant haemoglobins and the diagnosis of β thalassaemia.MethodsA Capillarys 2 Flex Piercing instrument with Phoresis software was evaluated in our laboratory over a 6-week period, comparisons being made with high performance liquid chromatography (HPLC) and, for haemoglobin A2 quantification, with microcolumn chromatography.ResultsThe instrument was easy to use and was suitable for the quantification of haemoglobin A2. Quantification of A2 was precise and the percentage was stable with ageing of the blood specimen. Results differ among HPLC, CE and microcolumn chromatography and use of an instrument-specific, method-specific reference range is therefore recommended until such time as there is standardisation between methods and manufacturers. Common variant haemoglobins were provisionally identified without difficulty. There are some uncommon variant haemoglobins that are detected by HPLC but not by capillary electrophoresis, but the reverse also occurs.ConclusionsCapillary electrophoresis using a Capillarys 2 Flex Piercing instrument is suitable for haemoglobinopathy diagnosis.

Inner space- and architecture-controlled nanoframes for efficient electro-oxidation of liquid fuels

2019 ◽  
Vol 7 (33) ◽  
pp. 19280-19289 ◽  
Author(s):  
Daowei Gao ◽  
Shuna Li ◽  
Guolong Song ◽  
Mingchuan Luo ◽  
Yipin Lv ◽  
...  
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Liquid Fuels ◽  
Electro Oxidation

Three-dimensional PtCuNi NFs with tunable inner architecture and composition are synthesized with high performance for the MOR and FAOR.

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