A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM.

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Wide range modeling study of dimethyl ether oxidation

: Partial contents: Non-Premixed turbulent combustion; Premixed turbulent combustion; Elementary reactions kinetics; Kinetic mechanisms--models and experiments; Laminar premixed flames; Laminar diffusion flames; Microgravity combustion; Chemical flame inhibition; Fire safety; Spray combustion; Catalytic combustion. p1-16 pages vary. Materials synthesis; Metals combustion; Propellants; NOx formation and control; Soot formation and destruction; Incineration and fuel substitution; Diesel engines; Spark ignition engines; Gas turbines; Active combustion control; High speed combustion; Detonations; Coal and char combustion; Fluidized beds; Porous media, fixed bed combustion, and furnaces,

Twenty-Sixth Symposium (International) on Combustion, Volume 2.

Exhaust emissions from diesel engine powered vehicles are considerably high during cold start and warm‐up, because of the poor catalyst performance due to the insufficient catalyst temperature. The controlled heat injection allowed by electrically heated catalysts can effectively reduce the catalyst light‐off time with relatively moderate fuel penalty. This paper compares the exhaust temperature and emissions of a case study diesel vehicle in cold and warm start conditions, and proposes two electrically heated catalyst control strategies, which are evaluated in terms of emission reduction and energy consumption with different target temperature settings. In addition, a new performance indicator, that is, the specific emission reduction, is used to evaluate the after‐treatment system and associated thermal management. For the worldwide harmonized light vehicle test cycle, the results without electrically heated catalyst show that from both cold and warm start conditions a large amount of operating points of the engine is located in the region of partial catalyst light off. Moreover, emissions, especially in terms of carbon monoxide and hydrocarbon, significantly decrease with the electrically heated catalyst implementation, for example, by at least 50% from cold start; however, they still tend to be rather substantial when the fuel is re‐injected after the engine cutoff phases. The exhaust temperature is lower than the target values in the sections of the driving cycle in which the electrically heated catalyst power is saturated according to the maximum level allowed by the device. The carbon dioxide penalty brought by the electrically heated catalyst ranges from 3.93% to 6.65% and from 6.49% to 9.35% for warm and cold start conditions, respectively.

On the emission reduction through the application of an electrically heated catalyst to a diesel vehicle

Experimental analysis and modeling of internal combustion engine operating with wet ethanol

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Ethanol as a Fuel for Road Transportation Main Report

Combusting ethanol-water fuels with a Catalytic Plasma Torch (CPT) promises to reduce pollutant emissions from low-compression engines in urban areas. This project involves obtaining a van with a spark-ignition (SI) engine from Valley Transit and working with Aqualytic Technologies Inc. to convert the vehicle to burn aquanol as well as gasoline. Upon completion, the vehicle will be used on a daily basis as part of the Valley Transit van fleet in Lewiston, Idaho. Emission and performance data will be collected periodically to verify durability of the catalytic ignition system. The goal of this project is to demonstrate the feasibility of retrofitting a spark ignition engine for catalytic operation and to monitor long-term operation in a public transit application.

Homogeneous charge combustion of aqueous ethanol

Aqueous Ethanol Fueled Catalytic Ignition Engine

The A platinum (pt) wire was used to study surface reactions with fuel-lean mixtures of propane and oxygen in a plug flow reactor under low Re flow regimes. The average wire temperature, catalytic ignition temperature, power at ignition, and heat generation were determined by measuring the voltage of current supplied to 127 µm ‘seasoned’ Pt wires. The average wire temperature and catalytic ignition temperatures are reported with a 3 percent error, while the average power and power at ignition are reported with an 8.5 percent error. A one step surface reaction model was used to find values of the ratios of the sticking coefficients SO2;O/SF;O = 5.25±12%, the pre-exponential constant for oxygen desorption, AO2;D = 1.99E12±165% 1/s), and the activation energy for oxygen desorption, EO2;D = 47±17%kJ/kmol, for propane-oxygen mixtures on Pt. These values were within the uncertainty reported for other hydrocarbon fuels. The model predicted the ignition temperature to within 1%. However, predicted rates of heat generation were as much as two orders of magnitude higher than measured. The results will assist the design and modeling of catalytic igniters used in engines burning under fuel-lean conditions. Future research will introduce water and use aqueous ethanol.

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Catalytic ignition temperatures of propane-oxygen-nitrogen mixtures over platinum

The use of one-dimensional computation fluid dynamic (CFD) engine simulation is an essential tool to the engine development process Engine design through simulation can drastically reduce time needed to perform engine experiments and prototyping, as most engine experiments can be simulated within the software As long as a model can be validated to high degree of accuracy (ie ±5%), the model can be used with a high level of confidence to optimize engine parameters This work used only a small fraction of WAVE’s potential More sophistication is possible in the areas of combustion kinetics, computational fluid dynamics, and emissions abatement through the use of advanced features and co-simulation The intention of this research was to lean the process of one-dimensional CFD engine simulation and document what has been learned about the process as well as the potential of the software for future work The research opportunities available with this software are endless and far-reaching The software can also be used as essential engine technology tool in technical elective courses such as ME433 – Combustion Engine Systems Any questions that may arise about standard engine operation or combustion process can be investigated with WAVE

One-Dimensional Engine Modeling and Validation Using Ricardo Wave

Aqueous fuels have the potential for lower emissions and higher engine efficiency than can be experienced with gasoline or diesel fuels. Past attempts to burn aqueous fuels in over-the-road vehicles have been unsuccessful due to difficulties in initiating combustion. For this project, the authors adapted and used SmartPlug (TM), catalytic igniter technology developed by Automotive Resources, Inc. (Sandpoint, Ohio)-in a transit van supplied by Valley Transit of Lewiston, Idaho. The adaptation entailed retrofitting the cylinders with total seal piston rings, installing corrosion-proof components in the fuel system, and reprogramming the fuel computer. They completed several hundred miles of vehicle testing to demonstrate the robustness of the conversion. Future emission studies are planned to quantify the emission reduction associated with the use of aqueous fuels. The information gained on this project will enable future conversions achieving higher efficiencies and lower emissions than currently possible on existing platforms.

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J Steciak

Papers

Homogeneous charge combustion of aqueous ethanol

Aqueous Ethanol Fueled Catalytic Ignition Engine

Catalytic ignition temperatures of propane-oxygen-nitrogen mixtures over platinum

One-Dimensional Engine Modeling and Validation Using Ricardo Wave

Catalytically assisted combustion of aquanol in demonstration vehicles