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Video

Characterization and Potential of Dual Fuel Combustion in a Modern Diesel Engine

2011-12-05
Diesel Dual Fuel, DDF, is a concept which promises the possibility to utilize CNG/biogas in a compression ignition engine maintaining a high compression ratio, made possible by the high knock resistance of methane, and the resulting benefits in thermal efficiency associated with Diesel combustion. Presenter Fredrik K�nigsson, AVL Sweden
Video

Blue Bird Propane Powered Vision School Bus

2012-04-10
Propane autogas, the world?s third most-used engine fuel, powers vehicles, transit buses, and now school buses. Blue Bird has recently launched the Next Generation Vision type C school bus, powered by a ROUSH CleanTech liquid propane autogas fuel system and a Ford 6.8L V10 engine. The bus reduces operating costs by up to 40%, greenhouse gas emissions by up to 24%, and maintains the factory horsepower, torque, and towing capacity ratings. Learn about how school districts are saving over $.30 / mile using this clean, domestically-produced fuel. Presenter Brian Carney, Roush CleanTech.
Video

Propane Autogas: The Clear Choice

2012-04-10
The presentation by Tucker Perkins, President of CleanFUEL USA, provides important information to those wanting to learn about alternative fuels, specifically propane autogas. CleanFUEL USA provides liquid propane injection engine system for the 6L engine in the GM G4500 cutaway chassis used in many Type A busses. They are also developing an 8L engine in partnership with Freightliner/ThomasBuilt Bus for the Type C bus. This presentation discussed many of the advantages of propane autogas use, such as better economics, lower emissions, and inexpensive infrastructure for the fueling network. Presenter Tucker Perkins, CleanFUEL USA
Video

Powertrain Innovation Requires Infrastructure Innovation!

2012-04-10
Who are the people who know the most about the buses in your fleet? They are most likely the operators and the servicing technicians. They are also the key people whose knowledge, level of training and attitude can determine the success or failure of new powertrain technologies. Training and recruitment of both need to be held to a higher standard than we have seen in the past. I will argue that even the culture of those involved in fleet operations needs to be changed. The bar for technical competence and product knowledge needs to be raised for operators and technicians. In return managers should find ways to include them as stakeholders, investing them with both additional responsibility and accountability. This will require greater access to training and recognition of achievement. Where are the busses stored and serviced? Most likely in an all-purpose state/county/municipal service facility servicing a variety of equipment.
Video

Natural Gas for School Buses: A Case for Using the Only Domestically Produced Alternative Fuel

2012-04-10
A review of the processes that lead to the conclusion that CNG was the best solution for the fleet, including the efforts to gain public support for alternative fuels for school buses. MISD is now home for 42 CNG powered school buses (of 200). The presentation will include training and design tips for safety and smooth operations along with maintenance considerations for using CNG. Alternative fuels, the dilemma of which comes first - refueling station or operational buses ? has an impact on grant approval and funding, bearing discussion of the option of a public/private model. Unlike other alternative fuels, CNG has a national security impact Presenter Charles Stone, Mansfield Indep School Dist
Collection

Natural Gas Engines and Vehicles, 2013

2013-04-09
The 9 papers in this technical collection cover fuel injection, combustion, controls, performance and emissions of SI engines fueled with methane based fuels such as natural gas, producer gas, coke oven gas or hydrogen-natural gas blends.
Collection

Natural Gas Engines and Vehicles, 2011

2011-04-12
The 5 papers in this technical paper collection cover natural gas engines and vehicles. Topics include: sliding mode control of air path in diesel-dual-fuel engine; optimization of natural gas automotive engine cooling jacket using CFD analysis; waste coke oven gas used as a potential fuel for engines; and more.
Technical Paper

LPG and Prechamber as Enabler for Highly Performant and Efficient Combustion Processes Under Stoichiometric Conditions

2021-09-05
2021-24-0032
The European Union has defined legally binding CO2-fleet targets for new cars until 2030. Therefore, improvement of fuel economy and carbon dioxide emission reduction is becoming one of the most important issues for the car manufacturers. Today’s conventional car powertrain systems are reaching their technical limits and will not be able to meet future CO2 targets without further improvement in combustion efficiency, using low carbon fuels (LCF), and at least mild electrification. This paper demonstrates a highly efficient and performant combustion engine concept with a passive pre-chamber spark plug, operating at stoichiometric conditions and powered with liquefied petroleum gas (LPG). Even from fossil origin, LPG features many advantages such as low carbon/hydrogen ratio, low price and broad availability. In future, it can be produced from renewables and it is in liquid state under relatively low pressures, allowing the use of conventional injection and fuel supply components.
Technical Paper

Under-Expanded Jets Characterization by Means of CFD Numerical Simulation Using an Open FOAM Density-Based Solver

2021-09-05
2021-24-0057
Among the others, natural gas (NG) is regarded as a potential solution to enhance the environmental performance of internal combustion engines. Low carbon-to-hydrogen ratio, worldwide relatively homogeneous distribution and reduced price are the reason as, lately, many researchers efforts have been put in this area. In particular, this work focuses on the characterization of the injection process inside a constant volume chamber (CVC), which could provide a contribution to the development of direct injection technologies for a gaseous fuel. Direct injection of a gaseous fuel involves the presence of under-expanded jets whose knowledge is fundamental to achieve the proper mixture formation prior to the combustion ignition. For this reason, a density based solver was developed within the OpenFOAM library in order to simulate the jet issued from an injector suitable for direct injection of methane.
Technical Paper

Effects of EGR, Variable Valve Timing, High Turbulence and Water Injection on Efficiency and Emissions of a HD Stoichiometric Natural Gas Engine

2021-09-05
2021-24-0048
The EU recently decided to reduce CO2 emissions of commercial vehicle fleets by 30% until 2030. One possible way to achieve this target is to convert commercial vehicle diesel engines into stoichiometric natural gas engines. Based on this, a commercial vehicle single cylinder diesel engine with variable valve actuation and high-pressure EGR is converted into natural gas operation to increase efficiency and thus reduce CO2. Additionally, a water injection system is integrated. All three technologies are investigated on their own and in combination. To reduce longer combustion durations caused by Miller valve timing and charge dilution, a piston bowl with extra high turbulence generation is designed. Additionally, a swirl variation is carried out. The results show, that high swirl motion and high turbulence can lead to a disadvantage in efficiency despite faster combustion durations due to higher wall heat losses.
Technical Paper

Characterization of Cycle-by-Cycle Variations of an Optically Accessible Heavy-Duty Diesel Engine Retrofitted to Natural Gas Spark Ignition

2021-09-05
2021-24-0045
The combustion process in spark-ignition engines can vary considerably cycle by cycle, which may result in unstable engine operation. The phenomena amplify in natural gas (NG) spark-ignition (SI) engines due to the lower NG laminar flame speed compared to gasoline, and more so under lean burn conditions. The main goal of this study was to investigate the main sources and the characteristics of the cycle-by-cycle variation in heavy-duty compression ignition (CI) engines converted to NG SI operation. The experiments were conducted in a single-cylinder optically-accessible CI engine with a flat bowl-in piston that was converted to NG SI. The engine was operated at medium load under lean operating conditions, using pure methane as a natural gas surrogate. The CI to SI conversion was made through the addition of a low-pressure NG injector in the intake manifold and of a NG spark plug in place of the diesel injector.
Technical Paper

Model Development of a CNG Active Pre-chamber Fuel Injection System

2021-09-05
2021-24-0090
Natural gas as an internal combustion engine fuel is taking a predominant role as a mid-term solution to pollution due to combustion driven human activities both in the energy and transport sectors. Engine researchers and manufacturers are in the process of investigating and improving strategies that decrease emissions and fuel consumption, without compromising engine performance and efficiency; active pre-chamber configurations are to be accounted for as one of these. A relatively small amount of fuel (up to 10 % of the total fuel-energy requirement) is introduced in the confined volume of the pre-chamber and forms a close-to-stoichiometric mixture with fresh charge that is introduced from the main combustion chamber during the compression stroke. After spark-ignition the products of this early stage of combustion can ignite ultra-lean mixtures (with λ up to 2) through the Turbulent Jet Ignition mechanism, hence reducing fuel consumption as well as noxious emissions such as NOx.
Technical Paper

Modeling of Three Way Catalyst Behavior Under Steady and Transient Operations in a Stoichiometric Natural Gas Fueled Engine

2021-09-05
2021-24-0074
Methane abatement in the exhaust gas of natural gas engines is much more challenging in respect to the oxidation of other higher order hydrocarbons. Under steady state λ sweep, the methane conversion efficiency is high at exact stoichiometric, and decreases steeply under both slightly rich and slightly lean conditions. Transient lean to rich transitions can improve methane conversion at the rich side. Previous experimental work has attributed the enhanced methane conversion to activation of methane steam reforming. The steam reforming rate, however, attenuates over time and the methane conversion rate gradually converges to the low steady state values. In this work, a reactor model is established to predict steady state and transient transition characteristics of a three-way catalyst (TWC) mounted in the exhaust of a natural gas heavy-duty engine.
Technical Paper

Development of Dual Fuel (Diesel + CNG) Engine for Off-Road Application

2021-09-22
2021-26-0119
The evolution of engine technology has so far seen the most beneficial side of progress in the fields of transportation, agriculture, and mobility. With the advent of innovation, there is also an impact on our environment that needs to be balanced. This is where fuels like CNG, LPG, LNG, etc. outperform conventional fossil fuels in terms of pollution & operational cost. This paper enlightens on the use of innovative dual-fuel technology where diesel & CNG fuels are used for combustion simultaneously inside the combustion chamber. Dual fuel system adaptation for farm application ensures self-reliance of the farmer where he can generate Bio-CNG to use the renewable fuel for farming making him less dependent on conventional fossil fuel thus promoting a green economy. The dual-fuel system is adapted to the existing in-use diesel engine with minimum modifications. This makes it feasible to retrofit a CNG fuel system on an existing diesel engine to operate it on dual fuel mode.
Technical Paper

Total Life Cycle Analysis of CNG and Hydrogen Enriched CNG Powered Vehicles: A Comparative Evaluation

2021-09-22
2021-26-0105
Vehicles consume energy and release harmful emissions throughout their life period from the manufacturing stage of raw materials to the vehicle scrapyard. The current Green-House Gas (GHG) emissions from diesel and petrol vehicles are reported to be 164 g CO2/km and 156 g CO2/km respectively. Thus, enormous research studies are been carried out for low-carbon alternative fuel-powered vehicles to reduce the overall GHG emissions. Numerous research on hydrogen as a transportation fuel has demonstrated the potential of reduced vehicular emissions compared to conventional fuels. Life cycle assessment (LCA) is a comprehensive methodology used for estimating the overall environmental impact of vehicles. In this present work, a comparative LCA is conducted between Compressed Natural gas (CNG) powered vehicles and H-CNG powered vehicles. The effect of the two alternative vehicles is assessed from various points in their lifetime using the GREET model software.
Technical Paper

EGR Strategies Pertaining to High Pressure and Low Pressure EGR in Heavy Duty CNG Engine to Optimize Exhaust Temperature and NOx Emissions

2021-09-22
2021-26-0114
CNG has proven to be a concrete alternative to gasoline and diesel fuel for sustained mobility. Due to stringent emission norms and sanctions being imposed on diesel fuel vehicles, OEMs have shifted their attention towards natural gas as an efficient and green fuel. Newly implemented BS VI emission norms in India have stressed on the reduction of Nitrogen Oxides (NOx) from the exhaust by almost 85% as compared to BS IV emission norms. Also, Indian Automotive market is fuel economy cautious. This challenges to focus on improving fuel economy but without increase in NOx emissions. Exhaust Gas Recirculation (EGR) has the potential to reduce the NOx emissions by decreasing the in-cylinder temperature. The objective of the paper is to model a CNG TCIC engine using 1D simulation in order to optimize the NOx emissions and maintain exhaust temperatures under failsafe limits.
Technical Paper

Development of an all Speed Governed Diesel-CNG Dual Fuel Engine for Farm Applications

2021-09-22
2021-26-0101
This paper discusses the development of an all speed governed diesel-natural gas dual fuel engine for agricultural farm tractor. A 45 hp, 2.9 liters diesel-natural gas dual fuel engine with a novel closed loop secondary fuel injection system was developed. A frugal approach without any modification of the base mechanical diesel fuel injection system was followed. This approach helped to minimize the cost impact, while meeting performance and emissions at par with neat diesel operation. Additional cost on gas injection system is redeemed by cost savings on diesel fuel. The dual fuel technology developed by Mahindra & Mahindra Ltd., substitutes on an average approximately 40% of diesel with compressed natural gas, meeting the TREM III A emission norms for dual fuel while meeting all application requirements. The governing performance of the tractor was found to be superior than base diesel tractor.
Technical Paper

Chemical Profiling of Exhaust Particulate Matter from Indian In-Service Vehicles

2021-09-22
2021-26-0192
Particulate matter is one of the major pollutant responsible for deteriorating air quality, particularly in urban centers. Information on contributing sources with the share from different sources is a first and one of the important steps in controlling pollution. Diverse sources, anthropogenic as well as natural, like industries, transport, domestic burning, construction, wind-blown dust, road dust contribute to particulate matter pollution. Receptor modeling is a scientific method which is utilized for assessment of the contribution of various sources based on chemical characteristics of particulate matter sources and ambient air particulate matter. Representative data of fractions of various chemical species in the particulate matter from the different sources i.e. source fingerprint is an essential input for the receptor modeling approach.
Technical Paper

The Study and Deep Insights of Port Injection Turbocharged CNG Engine Development for Trucks and Buses

2021-09-22
2021-26-0214
The intensifying demand of cleaner fuelled vehicles considering current norms of BSIV and upcoming stringent norms of BSVI with low cost solutions has promoted the development of CNG and dual fuel vehicles. CNG vehicle is anticipated to discover its extensive use for environment fortification and effective deployment of energy capitals. Thus, CNG vehicles can be pretty effective in averting environment deterioration. CNG has low carbon to hydrogen ratio, this leads to very low CO2 emissions compared to gasoline and diesel vehicles. CNG engines have the potential of low NOx and particulate emissions. Natural gas vehicle development has been directed on the way to current use of direct injection and port injection with S.I. engines. Generally for low cost development, all OEMs prefer optimization of existing engines. Similarly for this project, a diesel engine was converted to S.I. engine for development of low emission CNG engine.
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