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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"natural gas engines"”.
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Fundamental studies of flame propagation in lean-burn natural gas engines
<p>Lean-burn natural gas engines offer enhanced thermal efficiencies and reduced soot and NOx emissions. However, cycle-to-cycle variability in combustion that can result from unreliable ignition, variability in equivalence ratio and quenching is a challenge. Reliability of ignition can be improved …
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Characterization of the composition and toxicity of particulate matter emissions from advanced heavy-duty natural gas engines
Heavy-duty natural gas engines compliant with the 2010 EPA emissions standards have a clear advantage over diesel engines in meeting regulations with minimal after-treatment configuration. Heavy-duty natural gas engines are largely promoted as a cleaner burning engine with respect to low PM mass …
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NO<sub>x</sub> reduction for natural gas engines with increased ignition energy and plasma jet ignitors
… tested on a Waukesha ASTM-CFR engine fueled with natural gas. The pollutant emissions, fuel and air flow rates and dynamic cylinder pressure were measured for the full range of Air/Fuel ratios. From these measurements the indicated power and specific fuel consumption were calculated. The energy …
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A systems view of quality
… of construction and mining equipment, diesel and natural gas engines and industrial gas turbines, is committed to continually improving the quality of their products. Caterpillar currently employs many of the well-known quality techniques, such as statistical process control, yet experience …
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Improving the Efficiency of Gas Engines using Pre-chamber Ignition
… and understand the combustion phenomenon in engines operating on gaseous fuels, and develop technologies as an alternative to the present diesel engine technologies for heavy duty applications; which are facing severe challenges like stringent emissions norms, high technology costs and …
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Determination and analysis of natural gas vehicle tailpipe emissions based on continuous CVS measurement
… on the continuous measurement data obtained from natural gas vehicle emissions testing, a new approach was used in this study to calculate instantaneous DF of the CVS system during the test cycle. Using the instantaneous DF improves the accuracy of mass emission measurements, especially when the …
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Laser ignition for internal combustion engines via fiber optic delivery
… and improve the efficiency of Otto cycle engines, the ignition system is often a limiting factor. Many "high energy" ignition systems have been developed, but almost all of these are based on traditional electric arc spark plugs. Laser ignition represents a fundamentally different approach …
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Nitric oxide conversion in a spark-ignited natural gas engine
… percentage of stationary engine applications are natural gas fueled. The cleanest of these large bore engines currently produce on the order of one gram of NOx per brake-horsepower hour (g/bhp-hr) of work done. The goal of this work is to reduce these emissions to 0.1 g/bhp-hr levels. Selective …
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Oxidation catalyst degradation in the exhaust stream of a large bore 2-stroke natural gas engine
Lean burn 2-stroke natural gas engines are commonly used for power generation and gas compression. These engines, however, contribute to air pollution primarily through emissions of carbon monoxide, volatile organic compounds and some unburned hydrocarbons. Oxidation catalysts aid in reducing these …
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Computational fluid dynamics modeling of a large bore two-stroke natural gas engine
Natural gas fueled engines have been used for many years in stationary applications such as gas compression and electric power generation. In the United States alone, there are over 8,000 large bore (bore >30 cm) slow speed (speed < 500 rpm) natural gas engines in use. The most common configuration …
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Development and testing of a solid core fiber optic delivery system and ultraviolet preionization for laser ignition
Laser ignition of natural gas engines has shown potential to improve many facets of engine performance including brake thermal efficiency, exhaust emissions, and durability as compared with traditional spark ignition. Laser ignition technology has yet to transition to industry primarily because no …
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Dual fuel conversion of a direct-injection diesel engine
Dual fuel pilot-injected diesel natural gas engines offer significant potential to reduce oxides of nitrogen (NOx) and particulate matter (PK emissions while maintaining diesel-like efficiency. A 1994 Navistar T444E turbocharger V-8 diesel engine was converted to dual fuel diesel and compressed …
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Autoignition and emission characteristics of gaseous fuel direct-injection compression-ignition combustion
Heavy-duty natural gas engines offer air pollution and energy diversity benefits. However, current homogeneous-charge lean-burn engines suffer from impaired efficiency and high unburned fuel emissions. Natural gas direct-injection engines offer the potential of diesel-like efficiencies, but require …
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Evaluation of advanced air-fuel ratio control strategies and their effects on three-way catalysts in a stoichiometric, spark ignited, natural gas engine
… levels, engine emissions are under scrutiny. Natural gas engines are increasing in popularity over diesel engines, due to the high availability of fuel and fewer pollutant emissions than comparable diesel engines. Pollutants such as NOx, CO, and THCs (total hydrocarbons) are harmful to the …
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Diluted Operation of a Heavy-Duty Natural Gas Engine - Aiming at Improved Effciency, Emission and Maximum Load
Most heavy-duty engines are diesel operated. Severe emission regulations, high fuel prices, high technology costs (e.g. catalysts, fuel injection systems) and unsustainably in supplying fuel are enough reasons to convenience engine developers to explore alternative technologies or fuels. Using …
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Advanced control techniques and sensors for gas engines with NSCR
… reconfigured to operate utilizing an electronic gas carburetor (EGC2) with lambda sensor feedback, manufactured by Continental Controls Corporation (CCC) and a high reduction efficiency NSCR catalyst system manufactured by DCL International. A Data Acquisition (DAQ) system manufactured by …