I.c. engine intake manifold with telescopic runners of continuously variable length

摘要

The intake manifold 10, which provides airflow communication between a plenum volume 14 and a plurality of engine cylinders 16, has a telescopic arrangement of a permanent runner assembly 12, having a number of fixed length passages 24, and an active runner assembly 18, having a number of active runner passages 26. The extension and retraction of the active runner passages 26 is effected by a drive system 20 and a controller 22, eg in response to engine speed. The drive system may include a pinion gear 33 engaging gear teeth 32 on the active runner passages 26. The pinions 33 may be mounted on a common shaft to rotate together or may be individually driven via a clutch arrangement (36, fig.3). The runner passages 24,26 need not be of constant radius because a seal 28 and anti-rotation member 30 between the passages allows a clearance and/or the active runner passages may be flexible.