| 摘要 |
PURPOSE: An NOx reduction method is provided to minimize smog due to NOx generated by overheating by dropping temperature of an engine in cold start through adjustment of ignition timing of an engine. CONSTITUTION: An NOx reduction method for cold start comprises the steps of: detecting if temperature of cooling water is lower than a specific level; retarding ignition timing if the temperature of the cooling water is lower than 50deg.C; and igniting in a normal ignition timing if the temperature of the cooling water is over 50deg.C. If the temperature of the cooling water is over 50deg.C, a catalyst of a catalytic converter is in a fully activated state and NOx is not discharged by reductive reaction via the catalyst. Therefore, generation of smog is avoided.
|
