Multi-mode variable cam timing phaser

A variable cam timing phaser for an internal combustion engine including a housing assembly with an outer circumference for accepting drive force and a rotor assembly having at least one vane, the rotor assembly being coaxially located within the housing for connection to a camshaft, wherein the housing assembly and the rotor assembly define at least one vane chamber, the vane within the vane chamber acting to shift relative angular position of the housing assembly and the rotor assembly when fluid is supplied to the first chamber or the second chamber, the phaser comprising:

• a control valve for directing fluid from a fluid input to and from the first chamber and the second chamber through a first chamber line, a second chamber line, and a supply line coupled to the fluid input, the control valve comprising:
• a hollow sleeve with a plurality of ports, where at least two of the ports are connected by a first recess and at least two other ports are connected by a second recess;
• a spool received within the hollow sleeve comprising:
• a plurality of lands for selectively blocking the plurality of ports of the hollow sleeve;
• a working central passage located within the spool;
• an inlet passage located within the spool;
• a recirculation check valve received within the working central passage, limiting the flow of fluid between the first and second chambers through the working central passage;
• an inlet check valve received within the inlet central passage, allowing fluid from the fluid input to flow to the first and second chambers, and preventing flow from the first and second chambers to the fluid input during cam torque reversals;
• the control valve being movable between positions wherein the phaser operates in a plurality of modes under control of the control valve, the modes comprising:
• a first mode using cam torque to move the vane in a first direction, in which fluid from the first chamber is recirculating to the second chamber through the recirculation check valve;
• a second mode using cam torque to move the vane in the second direction, in which fluid from the second chamber is recirculated to the first chamber through the recirculation check valve;
• a third mode for holding the phaser in position, in which fluid is routed to the first and the second chambers from the fluid input through the inlet check valve of the spool;
• wherein in the first mode and second mode, makeup fluid is supplied from the fluid input to one of the first chamber or the second chambers through the inlet check valve of the spool;
• and
• wherein in the third mode, makeup fluid is supplied from the fluid input to both the first chamber and the second chamber through the inlet check valve of the spool.