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Investigation into producer gas utilization in high performance natural gas engines




Wise, Daniel M., author
Olsen, Daniel B., advisor
Caille, Gary, committee member
Marchese, Anthony, committee member
Sharvelle, Sybil, committee member

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A wide range of fuels are used in industrial gas fueled engines including well-head gas, pipeline natural gas, producer gas, coal gas, digester gas, landfill gas, and liquefied petroleum gas. Many industrial gas fueled engines operate both at high power density for increased efficiency and at ultra-lean air-fuel ratios for low NOx emissions. These two conditions require that engine operation occurs in a narrow air-fuel ratio band between the limits of misfire and the initiation of knock. The ability to characterize these limits for a given fuel is essential for efficient and effective engine operation. This work pursues two primary research objectives: (1) to characterize producer gas blends by developing prognostic tools with respect to a given blend's resistance to knock and (2) to develop a process to determine knock onset for a given fuel gas through direct indication from pressure transducer data at varied air-fuel ratios (ranging from stoichiometric to ultra-lean) as well as varied intake conditions (ranging from naturally aspirated to boosted intake pressures replicating turbocharged engines) and to quantitatively characterize the knock event using discreet and repeatable metrics derived from the analysis of the data. Methane number determination for natural gas blends is traditionally performed with research engines at stoichiometric conditions where the onset of knock is identified through subjective audible indication. To more closely replicate the operating conditions of a typical industrial engine, a Cooperative Fuel Research (CFR F2) engine is modified for boosted fuel/air intake and variable exhaust back pressure (to simulate turbocharger operation) with the incorporation of piezoelectric pressure transducers at the cylinder head to allow quantitative analysis of cylinder pressure conditions and transients precursive to, during, and following a knock event of varying magnitude. The interpretation of this data provides for evaluation of unique analytical methods to quantify and characterize engine knock under these conditions. In the course of this study an objective and consistent method for measuring methane number is developed, measured methane number for a total of 35 producer gas blends is provided, and a prognostic tool for predicting methane number, utilizing neural networks, is presented.


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producer gas
methane number


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