| 초록 |
Various technologies have been developed and applied to gasoline vehicles in order to satisfy the customer’s needs and the increasingly strict emissions regulations. Variable cam timing(VCT) systems are one of these technologies that are currently being used by the majority of automotive companies because they can improve engine performance and fuel economy, as well as reduce the regulated emissions by adjusting the valve timing. In conventional VCT systems, the oil control valve(OCV), which has a spool and solenoid function, is normally assembled into the cylinder head. Another type of VCT is the center bolt type VCT system. The control valve is being internalized into the bolt, which mounts the phaser, and the solenoid part is being shifted to the timing chain cover. In this paper, the possible problem of the hydraulic flow rate of the center bolt per the control requirement is described, and what needs to be considered when odifying the center bolt design for improving controllability is introduced. |
