High Power Igniter for Vehicles

Lean-burn engines have the potential to provide more efficient and cleaner operation. However, extremely lean mixtures are more difficult to ignite than the near-stoichiometric mixtures used in todays combustion engines. Reliably igniting extremely lean fuel-air mixtures requires more energy be efficiently delivered to the fuel charge than present-day spark ignition systems typically supply. A more efficient means of fuel ignition is through non-equilibrium plasma. This type of plasma initiates the ignition of fuel by the generation of various ionized species that are extremely chemically active, and thus promote the oxidation reactions which initiate combustion. In addition, with proper electrode design, the volume of plasma can be significantly greater than the spark produced by a conventional spark plug, enhancing the initiation of combustion. This type of plasma results from the application of large electric fields to a gas. In order to create this type of plasma, a fast rise time, short duration voltage pulse is required. Pulses with a slower rise time will result in the formation of an arc breakdown. Conventional ignition system designs are not capable of creating these fast rise times and short duration pulses, largely due to the parasitic inductance and capacitance in the ignition coil and to limitations on the speed and peak power of the switching devices used to drive the coil. In this SBIR, DTI will develop a lower repetition rate igniter that will be cost, form, fit, and function comparable to conventional ignition systems. The overall challenge in this SBIR is not meeting the pulse requirementsDTI has demonstrated a plasma ignition pulser whose operational requirements far exceed the requirements needed for automotive operation. In Phase I we will construct a prototype pulser and characterize its performance with an off-the shelf electrode. This prototype will be optimized to meet the small size, simple construction, and low cost needed for widespread use in the automotive market. Improving the ability to initiate and sustain combustion in lean fuel-air mixtures has the potential to provide enormous benefits. Internal combustion engines can be made more fuel-efficient and cleaner burning through the use of lean-burn techniques (the excess air associated with lean fuel-air mixtures promotes complete combustion as well as lowering peak combustion temperatures and thus the potential for reduced nitrogen oxide emissions). Key industries that would benefit from this technology would be the automotive, stationary engine, aircraft, and potentially stationary burner manufacturers and users. The technology is readily adaptable for the various operating points needed by these applications.