APPARATUS AND METHOD FOR DETECTING MISFIRE USING VARABLE VALVE LIFT APPARATUS OF VEHICLE

摘要

PURPOSE: A misfire determining apparatus and method using a variable valve lift device for a vehicle are provided to improve reliability by the occurrence of actual misfire and final misfire based on an engine roughness value which is received after correcting an intake valve to a set final valve lift value. CONSTITUTION: A misfire determining apparatus using a variable valve lift device for a vehicle comprises a misfire symptom sensing unit, a final valve lift value setting unit, and an actual misfire determining unit. The symptom sensing unit senses misfire symptoms based on an engine roughness value after starting an engine and determines misfire symptoms when the engine roughness value is reduced below a predetermined threshold. The final valve lift value setting unit sets a final valve lift value based on an offset valve lift value, which is calculated based on a first engine roughness value in segment short time of each cylinder after sensing misfire symptoms, and a reference valve lift value, which is calculated based on a second engine roughness value in segment long time. The final valve lift value setting unit includes a valve lift correcting member for correcting the valve lift of an intake valve to the final valve lift value. The actual misfire determining unit controls the intake valve with a valve lift value corrected by the final valve lift value and determines actual misfire based on the received variation of engine roughness value. [Reference numerals] (100) Sensing misfire symptoms; (300) Setting a final valve lift value; (500) Determining a misfire; (AA) Start; (BB) End