| 摘要 |
<p>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 12 having a spool 19 slidably located within a bore 18 in a valve sleeve 17. The spool 19 comprises one land dividing the bore 18 into a valve advance chamber 21 and a valve retard chamber 22, with the valve retard chamber 22 and the valve advance chamber 21 both being connected to a hydraulic oil supply. The valve advance chamber 21 and the valve 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 spool cause rotation of the vane. Such an arrangement allows the position of the angle of the vane to be determined directly by the position of the spool and to have a swift VCT response rate.
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