Visar resultat 1 - 5 av 18 avhandlingar innehållade ordet Autoignition.
Sammanfattning : The modeling work developed in this thesis can be divided in two main areas of investigations: autoignition related to spark ignition engine and combustion and emissions formation in relation to diesel engines. A first version of a detailed kinetics engine simulation program, extended to handle full cycle calculations, was employed in order to demonstrate the strong effect that nitric oxide from the residual gas has on the autoignition onset. LÄS MER
Sammanfattning : Knock in SI engines limits both power density and fuel conversion efficiency. The main mechanisms with the potential to generate the cylinder pressure fluctuations generally observed during knocking combustion are discussed. It is reasoned that some mechanisms of flame acceleration can further amplify a shock wave generated by autoignition. LÄS MER
Sammanfattning : This thesis is based on experimental investigations into engine knock in, (a) a multi-cylinder turbocharged engine, and (b) a single-cylinder engine featuring optical access. The optical access facilitated the measurement of temperature in the end-gas using coherent anti-Stokes Raman spectroscopy (CARS). LÄS MER
Sammanfattning : To fully understand the elementary reactions behind the ignition of automotive fuels the interaction between the fuel components must be known. The ignition initiation is most often caused by loss of an H radical from a reactive fuel molecule, for example n-heptane. The formed alkyl radical is prone to react with oxygen under lean conditions. LÄS MER
Sammanfattning : Autoignition in SI engines is an abnormal combustion mode and may lead to engine knock which is an undesired phenomenon in SI engines. It may cause damage and it is a source of noise in engines. Knock limits the compression ratio of the engine and a low compression ratio means low fuel conversion efficiency of the engine. LÄS MER