| 摘要 |
PURPOSE:To provide optimum characteristic of ignition timing by controlling the ignition timing according to the displacement of a piston of a variable venturi carbureter. CONSTITUTION:When the air to fuel ratio A/F is set leaner using a variable venturi carbureter, it is desirable that A/F may depend on the rate Q of intake flow. In such desirable case, the rate between the displacement of a piston and the intake flow rate may be 1:1. A specific sliding section of the piston is detected to advance the ignition timing. If the flow rate of intake air in an intake passage (a) is increased, the piston 1 is pulled to the opposite side of the intake passage (a) so that a negative pressure of intake air is fed into the second negative pressure chamber B of a spark advance device. The optimum characteristic of ignition timing may be thus obtained. |
