Sökning: "engine knock"

Visar resultat 1 - 5 av 26 avhandlingar innehållade orden engine knock.

1. 1. 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

3. 2. 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

4. 3. 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

5. 4. Gasoline Engine HCCI Combustion - Extending the high load limit

   Författare :Daniel Dahl; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NVO; stratified charge; gasoline engine; high load; knock.; HCCI; stoichiometric; CAI; ringing; SCCI;

   Sammanfattning : There is an increasing global focus on reducing emissions of greenhouse gases.For the automotive industry this means reducing CO2 emissions of the vehiclesmanufactured, which is synonymous with reducing their fuel consumption oradapting them for using renewable fuels. LÄS MER

7. 5. On the Impact of Piston Motion and In-Cylinder Charge Composition on Energy Release, Auto Ignition and Emission Formation in Premixed Charge Internal Combustion Engines

   Författare :Ola Stenlåås; Förbränningsmotorer; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bränslen; sprängämnen; Carbochemistry; petrochemistry; fuels and explosives technology; Petrokemi; Internal Combustion Engine; Emission; SI; Spark Ignition; HCCI; Homogeneous Charge Compression Ignition; zone model; Chemical Kinetic; Engine simulation; Reformed Methanol; Hydrogen; Knock; Auto Ignition; NO; Piston Motion; Nitric Oxide; Premixed Charge;

   Sammanfattning : The results presented in this thesis can be divided into four areas of investigation: Investigation of the effect of new volume-crank angle relations on engine emissions, power and efficiency; investigation of nitrogen oxides effect on auto ignition and knock in SI engines; investigation of premixed SI and HCCI engine operation with the alternative fuels hydrogen and reformed methanol gas (RMG); software development of a detailed chemical kinetics zonal engine model. Model development of the in-house two-zone chemical kinetic code focused on expansion of the Jacobian matrix to allow simulations of variable in-cylinder charge. LÄS MER