| 摘要 |
<p>An engine crank angle detecting device that enhances the reliability of detection of a crank angle reference position while suppressing influences of variations in engine rotation. It comprises a ring gear (42) fixed to the crank shaft (41) of a single-cylinder engine (30), the ring gear (42) having a plurality of equispaced projections (teeth) (43) disposed around the periphery thereof and a single unequal spacing (tooth-lacking portion) (44), a crank angle sensor (3) for detecting the rising and falling edges at opposite ends of a projection (43) of the ring gear (42), the crank angle sensor (3) recognizing each projection (43) and unequal spacing (44) by detecting the tooth width of each projection (43) and the spacing between adjacent projections and calculating the ratio therebetween, the crank angle sensor (3) and unequal spacing (44) being so arranged that the unequal spacing (44) is detected when the piston (31) of the engine (30) is in the vicinity of the lower dead point.</p> |
