Current stoichiometric spark-ignited engine technologies require costly catalytic converters for reductions in tailpipe emissions. Load control is achieved by using a throttle, which is a leading contributor to reductions in efficiency. Spark-ignited lean burn natural gas engines have been proven to be more efficient and emit fewer pollutants than their stoichiometric counterparts. Load reduction in these engines can be achieved by regulating the air/fuel ratio of the intake charge thereby reducing the efficiency penalties inherent to throttling. Partially stratified charge (PSC) can provide further reductions in emissions and improvements in efficiency by extending the lean limit of operation. PSC is achieved by the ignition of a small quantity of natural gas in the vicinity of the spark plug. This creates an easily ignitable mixture at the spark plug electrodes, thereby providing a high energy ignition source for the ultra-lean bulk charge. Stratified charge engine operation using direct injection (DI) has been proposed as a method of bridging the throttleless load reduction gap between idle and ultra-lean conditions. A previous study was conducted to determine if PSC can provide a high-energy ignition source in a direct injected stratified charge engine. Difficulties with igniting the PSC injections in an air-only bulk charge were encountered. This study focuses on a fundamental Schlieren image-based analysis of PSC combustion. Natural gas was injected through a modified spark plug located in an optically accessible combustion bomb. The relationships between PSC injection timing, fuel supply pressure and spark timing were investigated. Spark timing is defined as the duration between commanded start of injection and the time of spark. As the fuel supply pressure was increased, the minimum spark timing that lead to successful combustion also increased. The largest spark timing window that led to successful combustion was determined to be 80 ms wide at an injection fuel supply pressure of 300 psi. The amount of unburned natural gas increased with increasing spark timing. A cold flow study of the PSC injection system was also conducted. The PSC injection solenoid was found to have a consistent average injection delay of 1.95 ms. The slope of the linear response region of observed injection duration to commanded injection duration was 8.4. Due to plenum effects, the average observed injection duration of the entire PSC system was an order of magnitude longer than the commanded injection duration and was found to vary significantly with fuel supply pressure.

This dissertation rethinks textual images of the other’s beauty, depicted in works by D. H. Lawrence, Muriel Spark, and Virginia Woolf, whose fascination with the other, called by this dissertation the beloved, urged them to inscribe the beloved’s original beauty in texts. Their works make perceptible the singularity of the beloved, while revealing the writers’ predicament in translating the beloved’s ineffability in texts. Taking the untranslatability of the beloved into consideration, this dissertation traces the ways in which these writers’ texts capture the beloved’s original beauty at moments of revelation, related to epiphanies entering the terrain of literary modernism. My study thereby scrutinizes the dynamics of images of beauty and their impacts on art and politics in the context of modernism. In doing so, I argue that the texts I consider express the beloved’s singularity in challenge of the beautified images that many other artists invented for self-directed purposes in the early and mid-twentieth century. First, I explore Lawrence’s creation of aesthetic spaces in Lady Chatterley’s Lover (1928) in keeping with his desire for making palpable visual spectacles through the text. Analyzing how this ambition helped to create the novel’s aesthetic scenes, I would like to define Lawrence as an aesthete whose aspiration lay in expressing the beauty of things. Then, I discuss Spark’s affection for her characters and her desire to visualize the figure’s originality in The Prime of Miss Jean Brodie (1961) and The Girls of Slender Means (1963). Considering Spark in relation to both modernists and Fascists, I propose that her making of the image of her character breaks away from Fascism’s aestheticization of human figures. Finally, I investigate Woolf’s love for words by focusing on “The Duchess and the Jeweller” (1938), a short story written for expressing various modes of beauty in words. Drawing to the represented link between words and smell, considered the most “wasteful” sense, I examine how the sensory medium makes perceptible intrinsic qualities of words, and argues that her depiction of words, linked to smell, reveals the anti-utilitarian nature of words, unconstrained by a craftsman’s manipulation of words.

No description available.

No description available.

Current stoichiometric spark-ignited engine technologies require costly catalytic converters for reductions in tailpipe emissions. Load control is achieved by using a throttle, which is a leading contributor to reductions in efficiency. Spark-ignited lean burn natural gas engines have been proven to be more efficient and emit fewer pollutants than their stoichiometric counterparts. Load reduction in these engines can be achieved by regulating the air/fuel ratio of the intake charge thereby reducing the efficiency penalties inherent to throttling. Partially stratified charge (PSC) can provide further reductions in emissions and improvements in efficiency by extending the lean limit of operation. PSC is achieved by the ignition of a small quantity of natural gas in the vicinity of the spark plug. This creates an easily ignitable mixture at the spark plug electrodes, thereby providing a high energy ignition source for the ultra-lean bulk charge. Stratified charge engine operation using direct injection (DI) has been proposed as a method of bridging the throttleless load reduction gap between idle and ultra-lean conditions. A previous study was conducted to determine if PSC can provide a high-energy ignition source in a direct injected stratified charge engine. Difficulties with igniting the PSC injections in an air-only bulk charge were encountered. This study focuses on a fundamental Schlieren image-based analysis of PSC combustion. Natural gas was injected through a modified spark plug located in an optically accessible combustion bomb. The relationships between PSC injection timing, fuel supply pressure and spark timing were investigated. Spark timing is defined as the duration between commanded start of injection and the time of spark. As the fuel supply pressure was increased, the minimum spark timing that lead to successful combustion also increased. The largest spark timing window that led to successful combustion was determined to be 80 ms wide at an injection fuel supply pressure of 300 psi. The amount of unburned natural gas increased with increasing spark timing. A cold flow study of the PSC injection system was also conducted. The PSC injection solenoid was found to have a consistent average injection delay of 1.95 ms. The slope of the linear response region of observed injection duration to commanded injection duration was 8.4. Due to plenum effects, the average observed injection duration of the entire PSC system was an order of magnitude longer than the commanded injection duration and was found to vary significantly with fuel supply pressure.

Internal combustion engine emissions are currently a major source of air pollution. The harmful impact of engine emissions can be reduced when engines are fuelled by alternatives to petrol and diesel such as natural gas. The use of lean burn technology in spark-ignition engines has been dominant; however, the lean burn technique can not economically satisfy the increasingly restricted future emission standards particularly for NOx emissions. In this thesis, the use of the stoichiometric air-fuel mixture with exhaust gas recirculation (EGR) technique in a spark ignition natural gas engine is investigated. The aim of the research is to optimize the key engine operating conditions in order to obtain the lowest NO emissions accompanied with low fuel consumption and high power. This is achieved via both experimental and computer simulation research. / PhD Doctorate

Thesis (M.S.)--University of Nevada, Reno, 2006. / "August, 2006." Includes bibliographical references. Online version available on the World Wide Web.

Thesis (M.S.)--University of Missouri--Rolla, 1982. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed ) Includes bibliographical references (p. 57-58).

Thesis (M.S.)--West Virginia University, 1998. / Title from document title page. "December 1998." Document formatted into pages; contains ix, 104 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 78-79).

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Ronald Matthews. Vita. Includes bibliographical references. Also available from UMI.