Technical Progress Report

An ignition source was constructed that is capable of producing a pulsed corona discharge for the purpose of igniting mixtures in a test chamber. The corona generator can also be used as the ignition source for one cylinder on a test engine. The first tests were performed in a cylindrical shaped chamber to study the characteristics of the corona and analyze various electrode geometries. Next a test chamber was constructed that closely represented the dimensions of the combustion chamber of the test engine at USC. Combustion tests were performed in this chamber and various electrode diameters and geometries were tested. Higher peak pressures and faster pressure rise times were realized consistently in all test chambers versus standard spark plug ignition. A test engine was purchased for the project that has two spark plug ports per cylinder to The data acquisition and control system hardware for the USC engine lab was updated with new equipment. New software was also developed to perform the engine control and data acquisition functions including cylinder pressure monitoring. A ceramic corona electrode has been designed that fits in the new test engine and is capable of withstanding the pressures and temperatures encountered inside the combustion chamber. The corona ignition system was tested on the engine and an increase in both peak pressure and IMEP were seen in the initial test. There are issues that must be addressed before on-engine testing can continue such as EMF interference from the corona generator and electrical insulation on portions of the piston and cylinder head to prevent arcing. The EMF issue can be solved with proper shielding and grounding and various ceramic coatings are being researched for electrical insulation