Reduction of Transient Particulate Matter Spikes with Decision Tree Based Control

Decision trees have been proposed as a basis for modifying table based injection to reduce transient particulate spikes during the turbocharger lag period. It has been shown that decision trees can detect particulate spikes in real time. In well calibrated electronically controlled diesel engines these spikes are narrow and are encompassed by a wider NOx spike. Decision trees have been shown to pinpoint the exact location of measured opacity spikes in real time thus enabling targeted PM reduction with near zero NOx penalty. A calibrated dimensional model has been used to demonstrate the possible reduction of particulate matter with targeted injection pressure pulses. Post injection strategy optimized for near stoichiometric combustion has been shown to provide additional benefits. Empirical models have been used to calculate emission tradeoffs over the entire FTP cycle. An empirical model based transient calibration has been used to demonstrate that such targeted transient modifiers are more beneficial at lower engine-out NOx levels.

A Decision-Tree-Based Approach to Smoke Spike Detection in a Heavy-Duty Diesel Engine

Smoke spikes occurring during transient engine operation have detrimental health effects and increase fuel consumption by requiring more frequent regeneration of the diesel particulate filter. This paper proposes a decision tree approach to real-time detection of smoke spikes for control and on-board diagnostics purposes. A contemporary, electronically controlled heavy-duty diesel engine was used to investigate the deficiencies of smoke control based on the fuel-to-oxygen-ratio limit. With the aid of transient and steady state data analysis and empirical as well as dimensional modeling, it was shown that the fuel-to-oxygen ratio was not estimated correctly during the turbocharger lag period. This inaccuracy was attributed to the large manifold pressure ratios and low exhaust gas recirculation flows recorded during the turbocharger lag period, which meant that engine control module correlations for the exhaust gas recirculation flow and the volumetric efficiency had to be extrapolated. The engine control module correlations were based on steady state data and it was shown that, unless the turbocharger efficiency is artificially reduced, the large manifold pressure ratios observed during the turbocharger lag period cannot be achieved at steady state. Additionally, the cylinder-to-cylinder variation during this period were shown to be sufficiently significant to make the average fuel-to-oxygen ratio a poor predictor of the transient smoke emissions. The steady state data also showed higher smoke emissions with higher exhaust gas recirculation fractions at constant fuel-to-oxygen-ratio levels. This suggests that, even if the fuel-to-oxygen ratios were to be estimated accurately for each cylinder, they would still be ineffective as smoke limiters. A decision tree trained on snap throttle data and pruned with engineering knowledge was able to use the inaccurate engine control module estimates of the fuel-to-oxygen ratio together with information on the engine control module estimate of the exhaust gas recirculation fraction, the engine speed, and the manifold pressure ratio to predict 94% of all spikes occurring over the Federal Test Procedure cycle. The advantages of this non-parametric approach over other commonly used parametric empirical methods such as regression were described. An application of accurate smoke spike detection in which the injection pressure is increased at points with a high opacity to reduce the cumulative particulate matter emissions substantially with a minimum increase in the cumulative nitrogrn oxide emissions was illustrated with dimensional and empirical modeling.

Representations of the Human/ Nonhuman Primate Divide: the Influence of Science, Fiction, and Science-Fiction on the Concept of 'Being Human'

For as far back as human history can be traced, mankind has questioned what it means to be human. One of the most common approaches throughout Western culture's intellectual tradition in attempts to answering this question has been to compare humans with or against other animals. I argue that it was not until Charles Darwin's publication of The Descent of Man and Selection in Relation to Sex (1871) that Western culture was forced to seriously consider human identity in relation to the human/ nonhuman primate line. Since no thinker prior to Charles Darwin had caused such an identity crisis in Western thought, this interdisciplinary analysis of the history of how the human/ nonhuman primate line has been understood focuses on the reciprocal relationship of popular culture and scientific representations from 1871 to the Human Genome Consortium in 2000. Focusing on the concept coined as the "Darwin-Müller debate," representations of the human/ nonhuman primate line are traced through themes of language, intelligence, and claims of variation throughout the popular texts: Descent of Man, The Jungle Books (1894), Tarzan of the Apes (1914), and Planet of the Apes (1963). Additional themes such as the nature versus nurture debate and other comparative phenotypic attributes commonly used for comparison between man and apes are also analyzed. Such popular culture representations are compared with related or influential scientific research during the respective time period of each text to shed light on the reciprocal nature of Western intellectual tradition, popular notions of the human/ nonhuman primate line, and the development of the field of primatology. Ultimately this thesis shows that the Darwin-Müller debate is indeterminable, and such a lack of resolution makes man uncomfortable. Man's unsettled response and desire for self-knowledge further facilitates a continued search for answers to human identity. As the Human Genome Project has led to the rise of new debates, and primate research has become less anthropocentric over time, the mysteries of man's future have become more concerning than the questions of our past. The human/ nonhuman primate line is reduced to a 1% difference, and new debates have begun to overshadow the Darwin-Müller debate. In conclusion, I argue that human identity is best represented through the metaphor of evolution: both have an unknown beginning, both have an indeterminable future with no definite end, and like a species under the influence of evolution, what it means to be human is a constant, indeterminable process of change.