The disclosure goes more in depth about model, simulation and test procedures for characterization of prototypical unducted fan VSC (UFVSC). The main feature of the UFVSC is its low profile fan, which decreases the inductance and results in wider operating range. The drawback of the UFVSC is its higher cost. The cost can be reduced by designing UFVSC having a higher profile fan and yet its very small in size. Hence model structure and modeling approach were changed to simulate a UFVSC with fan on the primary side and proposed a control technique to improve the output voltage performance of UFVSC. As fan generating noise is the one of the main drawback of the UFVSC, size and cost of this device must be considered with the noise itself. Therefore cost effective approach was employed to decrease the dimensions of a typical UFVSC by reducing the number of parts and still maintaining the device quiet without compromising performance. The developed VSC concept can be employed in the control of power applications where reactive power requirement and voltage regulation are challenging issues. The proposed control module ensures that the real power is supplied to the load and that the reactive power is absorbed from the main source. System model and simulation of the proposed control module and the simulation results are presented.
This thesis examines the possibility of methanol direct fuel injection (DFI) engines in an attempt to improve their performances and reduce their cost. In this study, the effects of the fuel injection timing, the temperature of the cylinder head, and the coolant temperature on the knock characteristics of DFI engines are determined. To validate the analysis, the knock and the recorded vibration emission signals are compared to those from the gasoline engine in a 4-cylinder, 2.0L DFI engine that was equipped with a knock sensor and a vibration sensor, as well as a piston shaft position sensor. The DFI engine exhibits higher engine knock levels and vibration levels than the gasoline engine. Furthermore, the knock and the vibration levels observed for higher levels of coolant temperature and cylinder head temperature were higher than those for the lower levels of coolant temperature and cylinder head temperature. Therefore, as the engine knock level increases, the coolant temperature must be maintained within a certain range. Similarly, the piston shaft vibration emission level increases; therefore, the cylinder head temperature must be maintained within a certain range. d2c66b5586