Recirculating hydraulic fluid control valve

A hydraulic fluid control valve, comprising:

• a valve housing having:
• a first fluid port configured to be fluidly connected to a first hydraulic actuation chamber;
• a second fluid port configured to be fluidly connected to a second hydraulic actuation chamber, the first and second hydraulic actuation chambers configured to receive and exit hydraulic fluid;
• and
• a spool disposed within a bore of the valve housing, the spool having:
• a first aperture;
• a second aperture;
• an outer annulus;
• and,
• an inner fluid chamber arranged radially inwardly of the outer annulus;
• and
• in a first axial position of the spool, the inner fluid chamber is configured to recirculate hydraulic fluid from the first hydraulic actuation chamber to the second hydraulic actuation chamber, the inner fluid chamber configured to receive the hydraulic fluid from the first hydraulic actuation chamber via the first aperture;
• and
• in a second axial position of the spool, the inner fluid chamber is configured to recirculate hydraulic fluid from the second hydraulic actuation chamber to the first hydraulic actuation chamber, the inner fluid chamber configured to receive the hydraulic fluid from the second hydraulic actuation chamber via the second aperture;
• and,
• each of the first aperture and the second aperture are continuously fluidly connected to each other when the spool is in at least one of the first axial position or the second axial position;
• or
• the inner fluid chamber is continuously open from the first aperture to the second aperture;
• and
• wherein the valve housing is absent of a vent port.

A hydraulic fluid control valve configured to be attached as a single unit to an internal combustion engine, the hydraulic fluid control valve comprising:

• a coil;
• an armature surrounded by the coil and configured to be actuated by a magnetic field generated by the coil;
• a push pin attached to the armature;
• a valve housing having:
• a first radial fluid port configured to be fluidly connected to a first hydraulic actuation chamber;
• a second radial fluid port configured to be fluidly connected to a second hydraulic actuation chamber;
• and,
• a third radial fluid port arranged between the first and second radial fluid ports, the third radial fluid port configured to be fluidly connected to a pressurized hydraulic fluid source;
• and,
• a spool disposed within a bore of the valve housing and actuated by the push pin, the spool having:
• a first outer land;
• a second outer land;
• an outer annulus formed by the first and second outer lands;
• and
• an inner fluid chamber configured to directly contact hydraulic fluid, the inner fluid chamber having a radial outer wall including:
• a first aperture arranged at a first spring end;
• a second aperture;
• and
• a third aperture arranged at a second end, opposite the first spring end, and the third aperture sealingly separated from the push pin;
• and
• the inner fluid chamber configured to:
• i) continuously fluidly connect the first, second, and third apertures to each other, ii) recirculate hydraulic fluid from either one of the first or second hydraulic actuation chambers to a remaining one of the first or second hydraulic actuation chambers, and iii) route hydraulic fluid to a vent passage of the hydraulic fluid control valve;
• and
• the first and second outer lands, the radial outer wall, and the first, second, and third apertures are all formed integrally with the spool.