ICE Ignition Using Transient Plasma Acceleration

Lean-burn gasoline engines have difficulty reliably igniting fuel mixtures at sufficiently high air to fuel ratios. Common ignition systems are based on a spark gap driven by a pulse transformer ignition coil). Unfortunately, these systems have small plasma excitation areas, are slow, wear down the spark plug electrodes, and are not suitable for high pressure engines. The use of transient plasma ignition systems has already been demonstrated as effective in standard gasoline engines. This work extends the application of transient plasma ignitions into high pressure, lean burn engines by developing a Spark Plug Equivalent device driven by a tailored high voltage, pulsed power source. Two objectives will be achieved in Phase I. First, transient plasma generation will be demonstrated at 100 atmospheres in dry air, with corona extending past the Spark Plug Equivalent and into the ignition chamber. This will be documented with a high speed camera in a pressure vessel with a window. Second, the ignition of lean fuel ratios of 20:1 at 100 atmospheres will be demonstrated at temperatures similar to those in an internal combustion engine. Phase II and beyond will demonstrate the implementation and reliable operation of transient plasma based ignition systems in lean burn, high pressure gasoline engines. This system will ignite a significantly larger volume of the engine cylinder when compared to a spark plug based system, minimizing the effects of a non-uniform fuel/air mixture. Thus, a faster burn rate with a more consistent burn will be achieved. When compared with standard ignition system timing, this method requires less advancement before the piston reaches top dead center, resulting in higher efficiency. The Corporate Average Fuel Economy standards set a 54.5 miles per gallon average fuel economy goal for 2025. This provides a strong incentive for automobile manufacturers to improve their fuel economy fleet wide. Transient plasma ignition has already demonstrated its ability to provide increased fuel economy in standard engines. Lean burn, high pressure engines provide another way to increase efficiency. The merger of these technologies provides one avenue that should be considered in order to meet the efficiency standards.