Two path two step actuator

An electro-hydraulically actuated engine valve, comprising:

• a hydraulic connector comprising a first hydraulic fluid port, a second hydraulic fluid port, and a hydraulic fluid outlet;
• a spool valve assembly, comprising a first spool inlet, a second spool inlet, a spool outlet, a first spool port, a second spool port, an actuatable spool, and actuation devices;
• an actuator, comprising:
• a hollow first piston comprising a first extant with a first outer diameter D1 and a second extant comprising a second outer diameter D2, where D1>D2;
• a second piston slidable within the first piston;
• and
• an actuator housing comprising a recess, a first tubular port in communication with the first piston, and a second tubular port in communication with the second piston;
• a valve stem assembly abutting the actuator housing;
• and
• a valve stem slidably housed in the valve stem assembly, the valve stem abutting the second piston, the valve stem comprising a valve head configured to adjust an opening or closing of a fluid exchange area of an engine block,
• wherein the first hydraulic fluid port and the second hydraulic fluid port are configured to connect to a source of hydraulic fluid,
• wherein the hydraulic fluid outlet is configured to connect to a sump,
• wherein the first spool inlet aligns with the first hydraulic fluid port, the second spool inlet aligns with the second hydraulic fluid port, and the spool outlet aligns with the hydraulic fluid outlet,
• wherein the spool further comprises grooves,
• wherein the spool is slidable in the spool valve assembly to slide the grooves in to and out of alignment with the first spool inlet, the second spool inlet, the spool outlet, the first spool port, and the second spool port,
• wherein the first extant has a length L1 and wherein the second extant has a length L2, and
• wherein the first tubular port extends for a length L4, where L4 L2,
• wherein the recess extends for a length L3, where L3>(L2+L1), and
• wherein the first piston and the second piston are housed in the recess.

A method of operating an electro-hydraulic actuator, the actuator comprising:

• a hollow first piston comprising a first extant and a second extant;
• a second piston slidable within the first piston;
• and
• an actuator housing comprising a recess, a first tubular port in fluid communication with the first piston, and a second tubular port in fluid communication with the second piston,
• wherein the first extant has a length L1 and wherein the second extant has a length L2,
• wherein the first extant has a diameter D1, wherein the second extant has a diameter D2 and D2<D1,
• wherein the first tubular port extends for a length L4, where L4 L2,
• wherein the recess extends for a length L3, where L3>L2>L1, and
• wherein the first piston and the second piston are housed in the recess,
• the method comprising:
• supplying fluid at a first pressure to the first tubular port;
• and
• supplying fluid at a second pressure to the second tubular port,
• wherein, when the first tubular port and the second tubular port receive a predetermined fluid pressure, the first piston travels slower than the second piston.

An actuator, comprising:

• a hollow first piston comprising:
• a first extant and a second extant;
• and
• an inner surface with a first edge and a second edge;
• a second piston slidable within the first piston, the second piston comprising:
• a third edge;
• and
• a ring;
• and
• an actuator housing comprising:
• a recess;
• a first tubular port in fluid communication with the first piston;
• and
• a second tubular port in fluid communication with the second piston,
• wherein the first piston and the second piston are housed in the recess,
• wherein the first tubular port extends alongside the second extant, and
• wherein the second piston is configured to travel between a first position where the third edge abuts the first edge and a second position where a ring surface of the ring abuts the second edge.