| 摘要 |
PURPOSE:To make it possible to utilize an inertia effect to the maximum extent all over a drive range by controlling air intake pipe length so that the pressure in an air intake pipe becomes maximum when an air intake cam opens or shuts in accordance with the range of the number of revolution of an engine. CONSTITUTION:Output signals from an air intake pipe pressure sensor 22 provided in the vicinity of an air intake valve 9 in a corresponding air cylinder are sampled with the signal of a cam open angle of the corresponding air cylinder obtained from a crank angle detection sensor 25 and a cam angle detection sensor 28 as a trigger in a controller 30. And air intake pipe length is changed by driving a stepping motor 119 so that the pressure in the air intake pipe becomes maximum at the shutting angle of the air intake pipe 9 in the range of low speed rotation, at the shutting angle or opening angle in the range of middle speed rotation and at the opening angle in the range of high speed rotation. Consequently, as the pressure in the air intake pipe becomes high when the air intake cam opens, a large amount of new air flows in so as to make it possible to widely improve the volumetric efficiency, when the cam opens.
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