| 摘要 |
PURPOSE: A method and a system for diagnosing the misfire of vehicles are provided to prevent the wrong judgment of the misfire. CONSTITUTION: A system for diagnosing the misfire of vehicles comprises a unit for determining a primary misfire(10), a computing unit(21), first and second comparison units, an ECU(Engine Control Unit)(27). The unit for determining a primary misfire determines the primary misfire if the difference between engine roughness and a pre-determined misfire reference value is more than a pre-set critical value. The computing unit receives engine PRM, and the engine roughness for a pre-set time, and integrates the difference between the received engine RPM and the average value of calculated engine RPM for a pre-determined time if the misfire is not determined. The first comparison unit compares an integrated value with a pre-set value. The second comparison unit compares variation in the engine roughness with the pre-set value. The ECU determines a secondary misfire or a normal ignition in a rough idle state. |
