| 摘要 |
PURPOSE:To lower the exhaust temperature easily to normal level by correction controlling the firing timing nearer to the lead angle side than the standard firing timing when the exhaust temperature has exceeded over the setting level under heavy load high rotation area of engine. CONSTITUTION:A firing timing controller 9 comprising a microcomputor will select the basic firing timing from a map on the basis of an engine rotation signal and a boost pressure signal provided from a negative pressure sensor 11. Then the firing timing is corrected to decide whether it is in the area for suppressing the exhaust temperature or not or whether it is in the heavy load/high rotation area or not from the boost pressure or rotation to enter into the heavy load/high rotation area, and upon exceeding of the exhaust temperature detected by an exhaust temperature sensor 8 over the setting level, an exhaust temperature lead angle correction value is added to the basic injection timing for every specific injection times considering the detection time delay of sensor 8 thus to perform lead angle correction of an ignitor 13. Consequently, the exhaust temperature can be lowered to normal level easily and quickly resulting in improvement of durability of exhaust system. |
