| 摘要 |
PURPOSE:To prevent ignition timing from becoming inappropriate due to abnormality in a knocking sensing system and prevent durability of an engine from deteriorating by calculating limit values of retardation angle compensation amount based on the retardation angle compensation amount and by keeping the retardation angle compensation of the ignition timing within the said limit values. CONSTITUTION:A rectified integral value Si for each cylinder outputted from a rectification integrator 6 and processed with analog-digital conversion is compared with a slice level S/L for checking the presence of knocking. If the value Si is not less than S/L, it is judged that there has been knocking. According to the presence or absence of knocking, retardation angle compensation DELTAADVi for each cylinder is calculated and, according to driving conditions, is compared with a basic advance angle value ADV and then variance of average value DELTAADVi and a limit value LiM of the retardation angle compensation amount are calculated. If there are cylinders for which DELTAADVi is greater than LiM, it is judged that a knocking sensing system has sensed abnormality and the retardation angle compensation amount DELTAADVi of the relevant cylinder is kept within the limit value LiM. As a result, durability of an engine can be prevented from deteriorating. |
