System and method for combined knock and torque timing control

摘要

An ignition control system for controlling ignition knock while maintaining minimum spark for best torque (MBT). Both knock control and MBT control are simultaneously utilized. During knock control, engine cycles are counted between successive knock detections. When the count is less than a first value, a retard signal is generated. An advance signal is generted when the count is greater than a second predetermined value. These retard and advance signals are accumulated as knock trim signals in RAM storage locations as a function of engine speed and load operating points for each cylinder. During MBT control, MBT trim signals are generated by determining convergence of an average difference in indicated mean effective pressure for each cylinder. These MBT trim signals are stored in another RAM as a function of speed and load operating points. Base ignition timing is then corrected by both the knock trim signal and corresponding MBT trim signal at each speed and load operating point.