| 摘要 |
PURPOSE:To remove an air bubble as well as to prevent oil from degradation, by interconnecting a hydraulic passage to a return passage when an oil pump remains unlifted, in case of a device which selects valve operation characteristics by means of hydraulic pressure. CONSTITUTION:Each of rocker arms 6 and 7 is shifted in the axial direction of a rocker shaft 9 by hydraulic pressure to be selectively added to each of hydraulic chambers 12 and 13 and comes into contact with each of cams 4a, 5a or 4b, 5b selectively according to engine conditions. The feed of oil to these hydraulic chambers 12 and 13 takes place by means of an oil pump 17 via both a hydraulic passage 42 and a control part 21. When a plunger 19 of the pump 17 still remains unlifted, an on-off valve gear 44A has the hydraulic passage 42 interconnected through to a return passage 45, replacing oil inside the hydraulic passage 42 with a fresh one by degrees, thus not only deaerating performance in time of starting is improved but also oil degradation is prevented. |
