METHOD FOR CONTROLLING IGNITION TIMING OF VVL TYPED ENGINE CYLINDER

摘要

Disclosed is a method for controlling the ignition timing of cylinders in a variable valve lift control system capable of preventing engine roughness in a section away from a minimum spark advance for best torque (MBT). The method for controlling the ignition timing of cylinders according to the present invention comprises: a step (a) of reducing torque deviation by retard-controlling the ignition timing of cylinders at which the torque is high based on engine roughness measuring values for the RPMs of an engine with an air fuel ratio set in an initial environment; a step (b) of deducting the ignition timing for the cylinders according to the torque deviation; and a step (c) of correcting the ignition timing in an MBT by retard or advance-controlling the base ignition timing relative to the ignition timing for the cylinders based on a ratio between the engine roughness measuring values for the RPMs of the engine with the set air fuel ratio and the current engine roughness for the RPMs of the engine. When the base ignition timing exists toward an advance section due to wrong deduction, it is retarded toward a retardance section to compensate the deviation between the cylinders. Thus, the present invention can minimize the engine roughness. [Reference numerals] (AA) Start; (BB) End; (S301) Is learning conditions satisfied?; (S303) Learn deviation between cylinders and control mixers of the cylinders; (S305) Receive, filter, and store the engine roughness for valve lifts and the RPMs of an engine; (S307) Calculate ignition timing compensation for the cylinders; (S309) Attribute weighting for the valve lifts and the RPMs of the engine; (S311) Apply the ignition timing compensation for the cylinders; (S313) Is the engine roughness reduced?; (S315) Forward directional control (Advance of base ignition timing); (S317) Deduct the ignition timing at which minimum engine roughness generates; (S319) Backward directional control (Retardance of the base ignition timing)