In an effort to increase efficiency and reduce pollutants, many engines are using increasing quantities of dilution with excess air or exhaust gas recirculation. The ability to reliably ignite and propagate the flame through the combustion chamber is a critical aspect to fully realizing the benefits of the dilution. The higher ignition energy requirements and slower flame propagation speeds can lead to penalties in terms of combustion efficiency, thermal efficiency, or failed ignition altogether. This issue can be additionally exacerbated by the increasing use of biofuels.
The Clean Combustion Engine Lab has several recent technology developments in ignition control and combustion engine control areas including prototypes of several high-energy spark ignition devices. These are based on the following recent intellectual property protections:
- Multi-pole ignition, multi-coil ignition (CAN Patent 2850790, US Patent 9441604)
- Elastic breakdown ignition in responsive distributions or “eBIRD” (CAN Patent 2901240, US Patent 14/821,596)
- Enhanced capacitor ignition (US Provisional Patent 62/174,448)
- Micro pre-chamber ignition
- Corona ignition (CAN Patent 2856543, US Patent 9484719)
The multi-pole distributed spark ignition system, igniters, and associated control methods were developed to implement multiple sites of high energy ignition within a single spark plug. The high frequency resonant corona ignition system was developed to achieve ignition and enhance the ignition flame kernel formation through promptly controlling the multiple plasma pilot and post discharges.
Engine test results
Engine tests using the multi-pole ignition system, the enhanced capacitor ignition system and the conventional spark ignition system (baseline) were conducted. Test results are displayed in the figure above. The application of the multi-pole ignition system and the enhanced capacitor ignition system have enhanced the controllability of combustion phasing under lean conditions. Furthermore, the new technologies can also reduce the combustion variations existed during engine operation under 10 bar IMEP.