Patent ID: 7231896

Claim:
A phaser for an internal combustion engine comprising: a housing having an outer circumference for accepting drive force; a rotor for connection to a camshaft coaxially located within the housing having at least one vane, wherein the housing and the rotor define at least one chamber, separated by the vane into an advance chamber and a retard chamber, the vane being capable of rotation to shift relative angular position of the housing and the rotor; a control valve comprising a spool having at least one land and at least one slot on an outer circumference of the spool defined by at least two edges at an angle, slidably mounted within a bore in the rotor, the spool being moveable to at least a first position, a second position, and a third position; an advance passage connecting the advance chamber to the control valve; a retard passage connecting the retard chamber to the control valve and a common passage connecting the advance passage to the retard passage having at least one check valve; a means for connecting the housing to the spool, such that the spool rotates with the housing and moves translationally relative to the rotor; and a supply line for supplying fluid to the spool valve of the phaser having a first end connected to supply and a second end connected to the spool valve; wherein when the spool is in the first position, the slot on the outer circumference of the spool is in fluid communication with the supply line and the common passage; wherein when the spool is moving to the second position, the slot on the outer circumference of the spool is in fluid communication with the supply line, the retard passage and the common passage, allowing fluid flow between the retard chamber and the advance chamber; wherein when the spool is moving to the third position, the slot on the outer circumference of the spool is in fluid communication with the supply line, the advance passage and the common passage, allowing fluid flow between the advance chamber and the retard chamber; and wherein the angles and placements of the edges of the slot are positioned such that the phase angle directly relates to an axial position of the spool.