초록 ▼

An engine spark timing control system and method for addressing various engine output torque constraints. Preignition and knock concerns are addressed according to the conventional practice of calibrating spark control table, and the most limiting of the drivetrain-related torque constraints is refe

An engine spark timing control system and method for addressing various engine output torque constraints. Preignition and knock concerns are addressed according to the conventional practice of calibrating spark control table, and the most limiting of the drivetrain-related torque constraints is referenced to such table to determine the additional retard, if any, required to satisfy such constraint. With this control, the preignition spark control table or any of the drivetrain-related torque constraints may be changed at will without violating the other constraints or calibrations.

대표청구항 ▼

In a spark ignition system for the engine of a motor vehicle drivetrain adapted to initiate combustion in various engine cylinders in accordance with a spark timing control signal supplied thereto, a method of operation comprising the steps of: looking up a basic spark timing value from a calibratio

In a spark ignition system for the engine of a motor vehicle drivetrain adapted to initiate combustion in various engine cylinders in accordance with a spark timing control signal supplied thereto, a method of operation comprising the steps of: looking up a basic spark timing value from a calibration table of empirically determined and previously stored timing values chosen to maximize engine output torque within engine durability and drivability constraints; computing a MBT torque value corresponding to the engine output torque which would be obtained with a MBT spark timing setting chosen to maximize engine output torque without regard for said engine durability and drivability constraints; determining a final engine overtorque value corresponding to the amount by which the computed MBT torque value exceeds an engine torque constraint corresponding to a drivetrain-related torque constraint; determining an overtorque spark retard value representative of the deviation from the MBT spark timing setting which would cause the engine output torque to be reduced from the MBT torque value in the amount of said final engine overtorque value; determining a calibration spark retard value representative of the deviation from the MBT spark timing setting inherent in said calibration table; retarding the basic spark timing value in accordance with a supplemental spark retard value determined in relation to the amount by which the overtorque spark retard value exceeds the calibration spark retard value; and supplying a spark timing control signal to said spark ignition system in accordance with the retarded basic spark timing value, thereby to limit the engine output torque in the amount required to satisfy said drivetrain-related torque constraint.