Method and system for closed loop combustion control of a lean-burn reciprocating engine using ionization detection

摘要

A system and method for controlling knock in a lean burn internal combustion (IC) engine includes a spark plug having an electrode, and an electrical circuit configured to provide a first voltage to the electrode and detect an ion current during a thermal-ionization phase of the combustion process, and provide a second voltage to the electrode to create a spark and initiate a combustion process within a combustion chamber. The engine includes a controller configured to monitor the ion current for a knock condition that includes at least an incipient knock condition, determine a spark crank angle timing of the IC engine where the incipient knock occurs, and adjust the spark timing of the IC engine to operate at a crank angle that does not exceed a threshold level beyond an incipient knock set point.