Abstract: A variable camshaft timing (VCT) system for an internal combustion engine is described. In one example, the system includes a spool valve that displaces oil from one phaser chamber to another phaser chamber when the spool valve is moved. The system may respond faster than systems that employ a pump to move oil between phaser chambers.

Abstract: An oil pressure relief valve for use in the lubrication system of an internal combustion engine is controlled by both pump outlet pressure 3 and pilot pressure 2. The action of the valve reduces the start-up pressure spikes associated with known pilot-operated valves, while also permitting a fuel economy benefit.

Abstract: 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.

Abstract: A check valve 50 for a vacuum pump 1 is disclosed in which opening of the check valve 50 is controlled by centrifugal force by arranging a valve member 40 to slide along a slide axis Y-Y inclined with respect to an axis of rotation of a housing 27 in which the valve member 40 is slideably supported. The housing 27 rotates with a rotor 10 of the vacuum pump 1 and, in a one embodiment, the slide axis Y-Y is arranged at a right angle with respect to the axis of rotation X-X so as to maximize the effect of centrifugal force on the valve member 40 as the housing 27 is rotated.

Abstract: An oil pressure relief valve for use in the lubrication system of an internal combustion engine is controlled by both pump outlet pressure 3 and pilot pressure 2. The action of the valve reduces the start-up pressure spikes associated with known pilot-operated valves, while also permitting a fuel economy benefit.