Variable lift actuator

An actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• a control spring biasing said control piston in at least one of said first and second directions;
• and
• a first chamber formed between said first end of said cylinder and said first side of said actuation piston, a second chamber formed by said second side of said control piston and said second end of said cylinder, a third chamber formed between said second side of said actuation piston and said first side of said control piston, a first fluid flow passageway between said first port and said first chamber, a second fluid flow passageway between said second port and said second chamber, and a third fluid flow passageway between said third port and said third chamber.

A control system for controlling an actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• and
• a control spring biasing said control piston in at least one of said first and second directions;
• wherein the first port communicates with a fluid supply system supplying a fluid, wherein said fluid supply system comprises a switch operable between at least a first and second position, wherein said fluid supply system supplies said fluid at a high pressure when said switch is in the first position, and wherein said fluid supply system supplies said fluid at a low pressure when said switch is in the second position.

A control system for an engine valve comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• a control spring biasing said control piston in at least one of said first and second directions;
• and
• a piston rod connected to said second side of said actuation piston and extending through an opening in said control piston, wherein said piston rod is connected to at least one engine valve.

An actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• and
• a control spring biasing said control piston in at least one of said first and second directions;
• wherein at least one of said first side of said control piston and said second side of said actuation piston comprise a recess.

An actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• an actuation chamber formed between said first end of said cylinder and said first side of said actuation piston, an exhaust chamber formed by said second side of said control piston and said second end of said cylinder, and a control chamber formed between said second side of said actuation piston and said first side of said control piston;
• a first fluid flow passageway communicating with said actuation chamber, a second fluid flow passageway communicating with said exhaust chamber, and a third fluid flow passageway communicating with said control chamber, wherein said second fluid flow passageway is more restrictive to fluid flow than said third fluid flow passageway;
• and
• a control spring disposed between said second side of said control piston and said second end of said cylinder.

An actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• an actuation chamber formed between said first end of said cylinder and said first side of said actuation piston, an exhaust chamber formed by said second side of said control piston and said second end of said cylinder, and a control chamber formed between said second side of said actuation piston and said first side of said control piston;
• a first fluid flow passageway communicating with said actuation chamber, a second fluid flow passageway communicating with said exhaust chamber, and a third fluid flow passageway communicating with said control chamber, wherein said third fluid flow passageway is more restrictive to fluid flow than said second fluid flow passageway;
• and
• a control spring disposed between said second side of said control piston and said second end of said cylinder.

An actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• an actuation chamber formed between said first end of said cylinder and said first side of said actuation piston, a control chamber formed between said second side of said control piston and said second end of said cylinder, and an exhaust chamber formed between said second side of said actuation piston and said first side of said control piston;
• a first fluid flow passageway communicating with said actuation chamber, a second fluid flow passageway communicating with said control chamber, and a third fluid flow passageway communicating with said exhaust chamber, wherein said third fluid flow passageway is more restrictive to fluid flow than said second fluid flow passageway;
• and
• a control spring disposed between said first side of said control piston and said second side of said actuation piston.

An actuator comprising:

• a cylinder defining a longitudinal axis and comprising a first and second end;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• an actuation chamber formed between said first end of said cylinder and said first side of said actuation piston, a control chamber formed between said second side of said control piston and said second end of said cylinder, and an exhaust chamber formed between said second side of said actuation piston and said first side of said control piston;
• a first fluid flow passageway communicating with said actuation chamber, a second fluid flow passageway communicating with said control chamber, and a third fluid flow passageway communicating with said exhaust chamber, wherein said second fluid flow passageway is more restrictive to fluid flow than said third fluid flow passageway;
• and
• a control spring disposed between said first side of said control piston and said second side of said actuation piston.

A method of controlling an actuator comprising:

• providing an actuator comprising:
• a cylinder defining a longitudinal axis and comprising a first and second end;
• a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• a first chamber formed between said first end of said cylinder and said first side of said actuation piston, a second chamber formed between said second side of said control piston and said second end of said cylinder, and a third chamber formed between said second side of said actuation piston and said first side of said control piston;
• and
• a control spring engaging said second side of said control piston;
• applying a first pressure to said first side of said actuation piston in said first chamber with a fluid moving through said first port;
• moving said actuation piston in said first direction in response to said application of said first pressure;
• applying a second pressure to said second side of said actuation piston in said third chamber with a fluid moving through said third port;
• engaging said first side of said control piston with said second side of said actuation piston;
• applying a third pressure to said second side of said control piston in said second chamber with a fluid moving through said second port;
• and
• biasing said second side of said control piston with said control spring.

A method of controlling an actuator comprising:

• providing an actuator comprising:
• a cylinder defining a longitudinal axis and comprising a first and second end;
• a first port communicating with said first end of said cylinder, a second port communicating with said second end of said cylinder, and a third port communicating with said cylinder between said first and second ends;
• an actuation piston disposed in said cylinder and moveable along said longitudinal axis in a first and second direction, said actuation piston comprising a first and second side;
• a control piston disposed in said cylinder, said control piston moveable along said longitudinal axis in a first and second direction and comprising a first and second side, wherein said first side of said control piston faces said second side of said actuation piston;
• a first chamber formed between said first end of said cylinder and said first side of said actuation piston, a second chamber formed between said second side of said control piston and said second end of said cylinder, and a third chamber formed between said second side of said actuation piston and said first side of said control piston;
• and
• a control spring disposed between said control piston and said actuation piston;
• applying a first pressure to said first side of said actuation piston in said first chamber with a fluid moving through said first port;
• moving said actuation piston in said first direction in response to said application of said first pressure;
• applying a second pressure to said second side of said actuation piston in said third chamber with a fluid moving through said third port;
• biasing said first side of said control piston with said control spring engaged with said second side of said actuation piston;
• and
• applying a third pressure to said second side of said control piston in said second chamber with a fluid moving through said second port.