Sökning: "autoignition"

Visar resultat 1 - 5 av 19 avhandlingar innehållade ordet autoignition.

1. 1. Full Cycle Engine Simulations with Detailed Chemistry

   Författare :Adina Gogan; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; plasmas; Gaser; Gases; fluid dynamics; aktuariematematik; programmering; operationsanalys; Statistik; actuarial mathematics; programming; operations research; Statistics; detailed kinetics; emissions; engine knock; autoignition; modeling; spark ignition engine; diesel engine; fluiddynamik; plasma; Technological sciences; Teknik; Thermal engineering; applied thermodynamics; Termisk teknik; termodynamik; Motors and propulsion systems; Motorer; framdrivningssystem; stochastic reactor model;

   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

3. 2. Engine Knock: Characteristics and Mechanisms

   Författare :Klaas Burgdorf; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; SWACER; SI engines; quasi-detonation; autoignition; developing detonation; knock;

   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

4. 3. Knock in Gasoline Engines - the Effects of Mixture Composition on Knock Onset and Heat Transfer

   Författare :Börje Grandin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; SI engines; knock; heat transfer; thermal-boundary layer; cooled EGR; coherent anti-Stokes Raman spectroscopy CARS ; autoignition;

   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

5. 4. Kinetic modelling of autoignition phenomena

   Författare :David Johansson; Pehr Björnbom; Johan Andrae; Ulf Henriksson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical engineering; Kemiteknik;

   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

7. 5. Development of Zonal Models for Analysis of Engine Knock

   Författare :Shahrokh Hajireza; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; homogeneous autoignition; engine knock; Zonal modeling; SI engine; hot-spot autoignition; exothermic centers; wall heat transfer; application of detailed chemical kinetic mechanism of n-heptane and iso-octane; Motors and propulsion systems; Motorer; framdrivningssystem;

   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