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	Speed effect on ionization Signal at Stoichiometric
	High speed combustion imaging to confirm ionization characteristics

Use of an exhaust oxygen sensor to regulate air/fuel (A/F) ratio is a common approach used in conjunction with an exhaust catalyst to reduce vehicle tailpipe emissions. However, the exhaust oxygen sensor remains non-functional for a certain period after a cold start. It was thought that other sensors could be used to regulate A/F ratio during the time when the exhaust oxygen sensor remains non-functional. Southwest Research Institute (SwRI) investigated use of an ion-current sensor for this purpose.

Approach

• In-cylinder ion sensing (sparkplug)

• Correlation of ion signal and A/F ratio

• Online calibration

Challenges

• Weak ion signal at light load and lean A/F

• Strong speed/load, fuel property effects

Tools Used

• RPECS™ with high-speed DAQ

• Ion sensing ignition system

Conclusion

Studies concluded that an ion-current sensor is a promising replacement for oxygen sensor during a cold start.

For more information about our powertrain control capabilities, or how you can contract with SwRI, please contact Jayant Sarlashkar at jsarlashkar@swri.org or (210) 522-5506.

powertraincontroltech.swri.org

| Engine and Vehicle R&D Department | Engine, Emissions & Vehicle Research Division | SwRI Home |

Southwest Research Institute^® (SwRI^®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 11 technical divisions.

December 28, 2012