Browse Publications Technical Papers 2000-01-1377
2000-03-06

Misfire Detection from Ionization Feedback Utilizing the SmartFire® Plasma Ignition Technology 2000-01-1377

To test the reliability of the SmartFire® ionization data as a parameter for detecting misfires, we fitted an inline-4 cylinder engine with in-cylinder pressure sensors and compared their data to that provided by ionization current sensing. The ignition circuitry was tested for its ability to recognize misfires, and for its potential to re-strike the ignition early enough in the cycle to provide smooth engine operation. Unique design features of the SmartFire ignition circuit enable the measurement of ion current as early as 300 microseconds after the initiation of the spark discharge, thereby allowing early detection of improper combustion.
We compared the indicated mean effective pressure (IMEP) to the integrated ionization signal. When a misfire was measured by the IMEP, the integrated ion signal indicated the misfire as well. The ignition circuitry successfully identified the cycles with improper combustion. The system was also able to indicate the need for an ignition re-strike in order to smooth out engine operation and perhaps avoid a complete misfire. Misfire detection for on-board diagnostics (OBD) and for ignition re-strike has broad applications in passenger vehicles. Detecting and controlling improper combustion through the ionization signal is likely to be particularly valuable, as it provides a low-cost method for meeting OBD requirements and extending catalyst life.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Effect of DPF Design Parameters on Fuel Economy and Thermal Durability

2012-01-0847

View Details

TECHNICAL PAPER

KE-Jetronic - A New Continuously Injecting Electronically Controlled Multipoint Injection System with Limp-Home Capability

820253

View Details

JOURNAL ARTICLE

Real Time Implementation of DOC-DPF Models on a Production-Intent ECU for Controls and Diagnostics of a PM Emission Control System

2009-01-2904

View Details

X