Three servovalve thrust reverser actuator system
The subject matter of this specification can be embodied in, among other things, an engine assembly having a nacelle partially surrounding an engine, and a thrust reverser having a first element movable relative to the nacelle between a stowed and deployed position, a first hydraulic actuator configured to move the first element between the stowed and deployed position, the first hydraulic actuator being connected to a fluid source and a return reservoir, and a second element movable between a stowed and deployed position, a second hydraulic actuator configured to move the second element between the stowed and deployed position, the second hydraulic actuator being connected to the fluid source and the return reservoir, and a fluid control system having a servo valve operable to selectively route fluid between the fluid source, the first hydraulic actuator, and the return reservoir, and a controller configured to operate the servo valve.
1 . An engine assembly, comprising:
a nacelle configured to at least partially surround an engine;
a thrust reverser coupled to the nacelle, the thrust reverser comprising:
a first thrust-reversing element movable relative to the nacelle between a first stowed position and a first deployed position,
a first hydraulic actuator operably coupled to move the first thrust-reversing element between the first stowed position and the first deployed position, the first hydraulic actuator being fluidically connected to a pressurized fluid source and a fluid return reservoir,
a second thrust-reversing element movable relative to the nacelle between a second stowed position and a second deployed position, and
a second hydraulic actuator operably coupled to move the second thrust-reversing element between the second stowed position and the second deployed position, the second hydraulic actuator being fluidically connected to the pressurized fluid source and the fluid return reservoir; and
a fluid control system comprising:
an electrohydraulic servo valve operable to selectively route fluid between the pressurized fluid source, the first hydraulic actuator, and the fluid return reservoir, and
a controller configured to operate the electrohydraulic servo valve;
wherein the first hydraulic actuator, the second hydraulic actuator, and the electrohydraulic servo valve are fluidically connected in parallel between the pressurized fluid source and the fluid return reservoir.
2 . The engine assembly of claim 1 , wherein the controller is configured to operate the electrohydraulic servo valve such that a first mechanical output of the first hydraulic actuator is urged toward positional synchronicity with a second mechanical output of the second hydraulic actuator.
3 . The engine assembly of claim 1 , wherein the fluid control system further comprises an isolation control unit including an isolation control valve operable to selectively inhibit or permit fluid flow between the second electrohydraulic servo valve, the pressurized fluid source, and the fluid return reservoir.
4 . The engine assembly of claim 1 , wherein:
the thrust reverser further comprises a third hydraulic actuator operably coupled to move the first thrust-reversing element between the first stowed position and the first deployed position, the third hydraulic actuator being fluidically connected to the pressurized fluid source and the fluid return reservoir; and
the fluid control system further comprises:
an additional electrohydraulic servo valve operable to selectively route fluid between the pressurized fluid source, the third hydraulic actuator, and the fluid return reservoir; and
another controller configured to operate the additional electrohydraulic servo valve.
5 . The engine assembly of claim 1 , wherein the fluid control system further comprises an anti-cavitation check valve residing on a return fluid line in fluidic communication with the fluid return reservoir, the anti-cavitation check valve configured to permit fluid flow from the fluid return reservoir to at least one of the first hydraulic actuator and the second hydraulic actuator, while inhibiting fluid flow from the at least one of the first hydraulic actuator and the second hydraulic actuator to the fluid return reservoir.
6 . The engine assembly of claim 1 , further comprising:
a first position sensor configured to provide a first position feedback signal representative of a position of a first mechanical output of the first hydraulic actuator, wherein the controller is configured to operate the electrohydraulic servo valve based on the first position feedback signal; and
a second position sensor configured to provide a second position feedback signal representative of a position of a second mechanical output of the second hydraulic actuator, wherein the controller is configured to operate the electrohydraulic servo valve based on the first position feedback signal and the second position feedback signal.
7 . A fluid control system configured to operate a first hydraulic actuator coupled to a first thrust-reversing element coupled to a nacelle of an engine assembly and a second hydraulic actuator coupled to a second thrust-reversing element coupled to the nacelle of the engine assembly, the fluid control system comprising:
an electrohydraulic servo valve operable to selectively route fluid between a pressurized fluid source, the first hydraulic actuator, and a fluid return reservoir; and
a controller configured to operate the electrohydraulic servo valve, wherein the first hydraulic actuator, the second hydraulic actuator, and the electrohydraulic servo valve are fluidically connected to the pressurized fluid source and the fluid return reservoir;
wherein the first hydraulic actuator, the second hydraulic actuator, and the electrohydraulic servo valve are fluidically connected in parallel between the pressurized fluid source and the fluid return reservoir.
8 . The fluid control system of claim 7 , wherein the controller is configured to operate the electrohydraulic servo valve such that a first mechanical output of the first hydraulic actuator is urged toward positional synchronicity with a second mechanical output the second hydraulic actuator.
9 . The fluid control system of claim 7 , wherein the fluid control system further comprises an isolation control unit including an isolation control valve operable to selectively inhibit or permit fluid flow between the second electrohydraulic servo valve, the pressurized fluid source, and the fluid return reservoir.
10 . The fluid control system of claim 9 , further comprising a third hydraulic actuator operably coupled to move the first thrust-reversing element between a stowed position and a deployed position, the third hydraulic actuator being fluidically connected to the pressurized fluid source and the fluid return reservoir; and
the fluid control system further comprises:
an additional electrohydraulic servo valve operable to selectively route fluid between the pressurized fluid source, the third hydraulic actuator, and the fluid return reservoir; and
another controller configured to operate the additional electrohydraulic servo valve.
11 . The fluid control system of claim 7 , further comprising an anti-cavitation check valve residing on a return fluid line in fluidic communication with the fluid return reservoir, the anti-cavitation check valve configured to permit fluid flow from the fluid return reservoir to at least one of the first hydraulic actuator and the second hydraulic actuator, while inhibiting fluid flow from the at least one of the first hydraulic actuator and the second hydraulic actuator to the fluid return reservoir.
12 . The fluid control system of claim 7 , further comprising:
a first position sensor configured to provide a first position feedback signal representative of a position of a first mechanical output of the first hydraulic actuator; and
a second position sensor configured to provide a second position feedback signal representative of a position of a second mechanical output of the second hydraulic actuator, wherein the controller is configured to operate the electrohydraulic servo valve based on the first position feedback signal and the second position feedback signal.