Improved Engines and Fuels through Studies in Knocking Combustion

摘要

The research explored the characteristics and sources of combustion generated particles that are emitted during knocking combustion in a spark ignited engine. Using the forward lobe of a laser mie scattering polar diagram, a size estimate of these particles has been made as between 0.3 and 0.9 microns. The work has shown that the frequency of particle emission correlates with the intensity of knock. Evidence suggests that these particles function as ignition sources in the end-gas, i.e., act as the symptom and cause of the anomalous combustion. The conjecture has been used to explain the roles of known anti-knock compounds, to suggest materials that have anti-knock properties, and to provide a novel explanation in the mechanism for the lowering of Research Octane Number of ethanol on addition of the known anti-knock, tetraethyl lead, to that fuel.