Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

James E Smith

Committee Co-Chair

Andrew Lowery

Committee Member

Roy Nutter


The Quarter-Wave Coaxial Cavity Resonator (QWCCR) Plasma Igniter is a spark ignition replacement system based on a novel technology. This system creates coronal plasma through the use of radio frequency voltage step-up. Because this device is an open loop resonant structure, it is sensitive to changes in the environment it operates in, the physical and the combustion environment. A relationship can be developed between the effects of the pressure in the combustion environment and the changes in resonance frequency experienced by the igniter. These diagnostic capabilities can be utilized to detect and alleviate misfires, incomplete fuel burns, etc. in an engine cycle.;A series of tests were conducted to prove these principles. The QWCCR plasma igniter was inserted into the Cooperative Fuel Research (CFR) test engine. Data was collected via an in-cylinder pressure computer and a network analyzer. The engine was set at different increments in crank angle to map the changes in the parameters at different volumes throughout the compression and power strokes. During these tests there was no fuel or combustion only air as the medium in-cylinder.;The results compare a baseline frequency calculated from the in-cylinder pressure data and an experimental frequency that was collected using the network analyzer. The percent error between these two is at a maximum 1.725%. Three-dimensional plots were created from this data to show that frequency and pressure can be predicted and to show that this is a valid means of tracking changes in the combustion chamber. The results demonstrate that QWCCR Plasma igniter can be used as a diagnostics tool. This validation provides numerous additional opportunities for diagnostic capabilities using the other fundamental parameters of the igniter physical and electro-magnetic properties.