Open / close control device of intake valve for Miller cycle engine

摘要

PURPOSE:To effect regulation to a miller cycle at a high speed area and to a diesel cycle at a low speed area by a method wherein a cylinder having one end making contact with a locker arm and the other end movement of which is controlled through a hydraulic pressure and the force of a spring is incorporated in a cross head which is vertically moved through a guidance of a guide by oscillation of the locker arm of an intake valve device. CONSTITUTION:With a locker arm 8 oscillated, a cross head 9 is vertically moved through guidance of a guide 10 and an intake valve 5 is also vertically moved to effect opening and closing operation. A cylinder 12 having one end making contact with the locker arm 8 and the other end held through the force of a spring 11 and by a hydraulic pressure is incorporated in the central part of the cross head 9. A space 13 between the cylinder 12 and the cross head 9 is communicated with the A port of a control valve 17 through oil passages 14, 15, and 16. During high speed rotation of an engine, a circuit pressure P is increased, a spool 20 is pushed leftward to intercommunicated A and B ports, oil in the space 13 is discharged to a tank 19, the stroke of the cross head 9 is decreased, and the intake valve is operated in a rapid closing miller cycle.