Abstract: This feature of the present invention comprises a method and apparatus which uses an ionization signal to optimize the air to fuel ratio AFR of the combustion mixture when the engine is operated at wide open throttle (WOT). This feature of the present invention optimizes the air to fuel ratio AFR on-line using the relationship between an air to fuel ratio AFR index CAFR and the air to fuel ratio AFR. In a preferred embodiment, the real-time control strategy adjusts the engine air to fuel ratio AFR based upon an air to fuel ratio AFR gradient parameter.

Abstract: This feature of the present invention comprises a closed loop which uses estimated MBT timing criteria and ignition diagnostics (knock, partial-burn, and misfire) to control engine ignition. When the engine is not knock limited, it operates at its MBT timing. When the engine is knock limited, the engine runs at its inaudible knock limit. When the engine is misfire/partial-burn limited, the engine is maintained at its misfire/partial-burn limit. Three different embodiments of the closed loop MBT timing control architecture are disclosed: a cylinder-by-cylinder control, an average control and a mixed control.

Abstract: This feature of the present invention is a robust multi-criteria minimum timing for the best torque (MBT) timing estimation method and apparatus utilizing different ionization signal waveforms that are generated under different engine operating conditions. This feature of the present invention determines and combines multiple MBT timing criteria to increase the reliability and robustness of MBT timing estimation based upon spark plug ionization signal waveforms. In a preferred embodiment, the present invention combines MBT timing estimation criteria comprising a maximum flame acceleration location, a 50% burn location, and a second peak location.

Abstract: Internal combustion engine (ICE) on-plug ignition coils with transistor drivers located in powertrain control modules (PCM) or other remote locations are prone to high electrical and magnetic interference (EMI) emissions and are subject to interference from other components due to long connecting wires. Ionization detection circuits have even greater sensitivity to EMI because of their very low signal current levels (microampere). The present feature of the invention integrates both the coil driver transistor and ionization detection circuits into the on-plug ignition coil. In a preferred embodiment, parts rated at 140 degrees centigrade are used in both the coil driver transistor and the ionization circuits which are located on the coil to address temperature and thermal shock concerns. Additionally, parts rated at 20 G are used in both the coil driver transistor and the ionization circuits to address vibration concerns.

Abstract: The present feature of the invention comprises a method and apparatus for determining cylinder ID. When a cylinder is compressed, the resistance increases across the spark plug gap. Thus, if a spark coil is only partially charged before activation of the spark, the air gap is not broken down and no ignition occurs in the cylinder in compression. The failure of a spark plug to spark is reflected in the ionization signal. In a preferred embodiment, the dwell time is selected so that the spark plug located in a cylinder that is not in compression will spark, while a spark plug in a cylinder that is in compression will not. The cylinder in compression will output an ionization signal with a shorter duration than a cylinder not in compression. In a preferred embodiment, two methods are used to calculate the duration of the spark, edge detection and integration.

Abstract: The present feature of the invention is generally directed to a subsystem of an ignition diagnostics and feedback control system using ionization current feedback. It utilizes the ionization signal from an ionization detection circuit to monitor ignition parameters, such as primary charge timing, primary charge duration, ignition/spark timing, and ignition/spark duration for future “smart” ignition system control. In addition, the ionization signal is also used to detect spark plug carbon fouling, as well as plug insulator overheating. These parameters can be monitored for every cylinder of the engine for each engine cycle.