Sökning: "variable compression"

Visar resultat 6 - 10 av 45 avhandlingar innehållade orden variable compression.

1. 6. Control of HCCI by aid of Variable Valve Timings with Specialization in Usage of a Non-Linear Quasi-Static Compensation

   Författare :Fredrik Agrell; Hans-Erik Ångström; Wai K. Cheng; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HCCI; Homogeneous; Charge Compression Ignition; Engine Control; Variable Valve Timings; Other technology; Övriga teknikvetenskaper;

   Sammanfattning : This doctoral thesis is about controlling the combustion timing of the combustion concept Homogeneous Charge Compression Ignition, HCCI, by means of variable valve timings. The HCCI research usually is regarded to have started in Japan during the later part of the 1970´s. The world of HCCI has since grown and HCCI is of today researched worldwide. LÄS MER

3. 7. Integrated Variable-Gain and CMOS Millimeter-Wave Amplifiers

   Författare :Mohammad Anowar Masud; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LNA; MMIC; FinFET; CMOS; HEMT; GaAs; WLP; VGA; BCB;

   Sammanfattning : Variable Gain Amplifier finds extensive use in the high frequency demonstrators specially those operating in the millimeter-wave regions and beyond where the incoming RF signal level can have wide variations. To maintain a constant signal level an IF VGA has been designed that can offer a dynamic variation of gain as much as 45 dB together with a high maximum gain and a low noise figure. LÄS MER

4. 8. HCCI Combustion by Retaining Residuals. Development and Analyses of a Method to Reduce Fuel Consumption for Passenger Car Gasoline Engines

   Författare :Lucien Koopmans; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; gasoline; variable valve timing; homogeneous charge compression ignition HCCI ; internal combustion engines; fuel-consumption; engine emissions; controlled auto-ignition CAI ;

   Sammanfattning : The demand for more powerful engines on one hand, and greater fuel-efficiency on the other, requires a revolution in engine combustion technology. Homogeneous charge compression ignition (HCCI) can be a fuel-saving, low emissions approach that seems to be very suitable for large displacement passenger car engines. LÄS MER

5. 9. Adaptive image compression with wavelet packets and empirical mode decomposition

   Författare :Anna Linderhed; Roland Wilson; Linköpings universitet; []
   Nyckelord :;

   Sammanfattning : This thesis addresses the problem of using wavelet packets and empirical mode decomposition (EMD) for image compression. The wavelet packet basis selection algorithm is studied through an extensive experimental survey of the generated decomposition trees. LÄS MER

7. 10. CFD Modelling of a Free-Piston Engine Using Detailed Chemistry

   Författare :Miriam Bergman; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; free-piston; combustion; Diesel; compression ignition; chemical kinetics; HCCI; Computational Fluid Dynamics;

   Sammanfattning : The Free Piston Engine, FPE, which is capable of operating in a variable compression ratio mode, is highly suitable for the promising Homogeneous Charge Compression Ignition (HCCI) concept, allowing flexible auto-ignition control on a cycle-to-cycle basis without any hardware modifications. In this study, the effects of varying the start of injection on the emission formation and efficiency of such an engine have been investigated, using simulations based on the KIVA-3V CFD code. LÄS MER