| 摘要 |
A variable camshaft timing (VCT) system 10 for an internal combustion engine includes a vane 13 mounted to the end of an engine camshaft, surrounded by a housing 14. The vane 13 separates a chamber in the housing 14 into a phaser advance chamber 15 and a phaser retard chamber 16. The VCT system 10 also includes a control valve (actuator) having a spool (piston) 19 slidably located within a bore 18 in a valve sleeve (cylinder) 17. The spool/piston 19 comprises one land dividing the bore 18 into an advance chamber 21 and a retard chamber 22 both connected to a hydraulic oil supply. The advance chamber 21 and the retard chamber 22 are in hydraulic communication with the phaser advance chamber 15 and the phaser retard chamber 16 respectively through an advance line 11 and a retard line 23, such that displacements of the piston 19, eg by a stepper motor or solenoid, cause rotation of the vane 13. Such an arrangement allows the position of the angle of the vane to be determined directly by the position of the piston and to have a swift VCT response rate. |
