| 摘要 |
PURPOSE:To improve durability in a spark plug at the trailing side by making an ignition timing change in the trailing side spark plug larger than that at the leading side at the time of knocking detection, in the case of a device which is provided with each spark plug at the leading side (L side) and the trailing side (T side). CONSTITUTION:A T side spark plug 13 and an L side spark plug 14 are attached to a middle stage part of a rotary housing 1 at a distance of top and bottom, thile a piezoelectric type knock sensor 15 is installed in side housing. An output signal of this knock sensor 15 is inputted into a control unit 18 as a knock pulse signal out of a knock control unit 16. And, at the time of knocking unoccurrence, ignition timing is controlled on the basis of engine speed and intake air quantity with a first map. On the other hand, at the time of knocking occurrence, each ignition timing of these spark plugs 13, 14 is retarded, but when a retard value exceeds the specified limit value, the T side spark plug 13 is stopped, and ignition timing of the L side spark plug 14 is controlled on the basis of a second map. |
