1. An acoustic structure comprising:
a plurality of resonance tubes; and
a plurality of openings formed on side faces of the resonance tubes at prescribed positions; and
at least one adjuster adjusting an opening area of the opening formed on the side faces of the plurality of resonance tubes.
2. The acoustic structure according to claim 1, further comprising:
a plurality of boards supporting the plurality of resonance tubes,
wherein each of the resonance tubes is divided into two tubes which are combined together with open ends positioned opposite to each other, and
wherein the two tubes forming each of the resonance tubes are movable independently in an axial direction along a pair of the boards interposing the resonance tube therebetween, thus adjusting the opening area of the opening of the resonance tube.
3. The acoustic structure according to claim 1, further comprising:
a plurality of adjusters which are independently movable to shield at least part of the plurality of openings formed in the plurality of resonance tubes while the plurality of resonance tubes are mutually moved in the axial direction, thus adjusting the opening area of the openings of the resonance tubes.
4. The acoustic structure according to claim 1, further comprising:
a plurality of boards supporting the plurality of resonance tubes,
wherein each of the boards is divided into two boards which are combined together with distal ends positioned opposite to each other,
wherein the plurality of openings are formed on predetermined side faces of the resonance tubes which are positioned opposite to each other when the plurality of resonance tubes are combined together, and
wherein the two boards are interposed between a pair of resonance tubes and independently movable in an axial direction so as to adjust the opening area of the opening of the pair of resonance tubes.
5. The acoustic structure according to claim 1, further comprising:
a sheet member, corresponding to the at least one adjuster, which is movable along a baffle surface formed by the side faces of the plurality of resonance tubes combined together,
wherein the plurality of openings is exposed on the side faces of the plurality of resonance tubes forming the baffle surface, and
wherein the sheet member is movable along the baffle surface to shield at least part of the plurality of openings exposed on the baffle surface.
6. The acoustic structure according to claim 1, wherein the at least one adjuster adjusts a ratio of the opening area of the openings of the resonance tubes to a sectional area of internal cavities of the resonance tubes.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A fuel injector comprising:
a barrel defining a first fluid passage, a second fluid passage and a piston bore including an upper bore and a lower bore;
an intensifier piston including a shoulder and a stepped top;
a first actuation cavity defined by said upper bore, said stepped top and said first fluid passage;
a second actuation cavity defined by said lower bore, said shoulder and said second fluid passage;
said piston being slidably received in said piston bore wherein said shoulder is received in said lower bore and said stepped top is received in said upper bore;
said stepped top having a first surface open to fluid pressure in said first actuation cavity and said shoulder having a second surface open to fluid pressure in said second actuation cavity;
said piston being moveable between a first position and a second position; said stepped top being sealable with said upper bore when said piston moves between said first position and said second position;
a source of actuation fluid;
a drain passage;
a control valve to open and close fluid communication between said first and second fluid passages and said source of actuation fluid and said drain passage.
2. The fuel injector of claim 1 wherein
said first surface defines a first area open to fluid pressure in said first actuation cavity; and
said second surface defines a second area open to fluid pressure in said second actuation cavity;
3. The fuel injector of claim 2 wherein said first area is smaller than said second area.
4. The fuel injector of claim 1 wherein said second surface is annular in shape.
5. The fuel injector of claim 2 wherein said first surface and said second surface are axially aligned.
6. The fuel injector of claim 1 wherein said piston isolates said upper bore from fluid communication from said lower bore.
7. The fuel injector of claim 1 further including a piston return spring.
8. The fuel injector of claim 1 further including a plunger actuated by said piston.
9. The fuel injector of claim 1 wherein said control valve includes a three position spool.
10. The fuel injector of claim 9 wherein said control valve opens said first and second fluid passages to said drain when said control valve is in a first position.
11. The fuel injector of claim 9 wherein said control valve isolates said first fluid passage from said drain and opens fluid communication between said first fluid passage and said source of actuation fluid when said control valve is in a second position.
12. The fuel injector of claim 9 said control valve isolates said first and said second fluid passages from said drain and opens fluid communication between said first and second fluid passages and said source of actuation fluid when said control valve is where in a third position.
13. The fuel injector of claim 1 wherein said control valve includes a solenoid.
14. A method of operating an intensifier piston arrangement, an intensifier piston having a first effective area and a second effective area, the method comprising:
delivering a first fluid flow from a common fluid source to said first area;
moving said intensifier piston a first preselected distance;
delivering a second fluid flow from said common fluid source to said second area;
moving said intensifier piston a second preselected distance;
maintaining said first area in direct fluid isolation from said second area.
15. The method of claim 14 further including sending a first signal and moving a valve from a first position to a second position.
16. The method of claim 15 further including sending a second signal and moving said valve to a third position.
17. The method of claim 16 further including sending a third signal and moving said valve to a first position and draining said fluid flow from said first and second areas.
18. The method of claim 15 further including sending a second signal and moving a second valve from a first position to a second position.
19. A method of operating a intensifier piston system comprising:
delivering a first signal;
moving a valve to a first position in response to said first signal;
allowing fluid flow to a first effective area of an intensifier piston;
delivering a second signal;
moving said valve to a second position in response to said second signal;
allowing a fluid flow to a second effective area of said intensifier piston.
20. The method of claim 19 wherein moving a valve to a first position includes moving a three position spool valve to said first position.
21. The method of claim 19 further including allowing said fluid flow to a stepped top of said intensifier piston.
22. The method of claim 19 further including allowing said fluid flow to a shoulder of said intensifier piston.
23. The method of claim 19 further including maintaining said first effective area in direct fluid isolation from said second effective area.
24. The method of claim 19 further including:
delivering a third signal;
moving said valve to a third position in response to said third signal; and
draining said fluid flow from said first and second effective areas.
25. An intensifier assembly comprising:
a barrel defining a first fluid passage, a second fluid passage and a piston bore including an upper bore and a lower bore;
an intensifier piston including a shoulder and a stepped top;
a first actuation cavity defined by said upper bore, said stepped top and said first fluid passage;
a second actuation cavity defined by said lower bore, said shoulder and said second fluid passage;
said piston being slidably received in said piston bore wherein said shoulder is received in said lower bore and said stepped top is received in said upper bore;
said stepped top having a first surface open to fluid pressure in said first actuation cavity and said shoulder having a second surface open to fluid pressure in said second actuation cavity;
said piston being moveable between a first position and a second position; said stepped top being sealable with said upper bore when said piston moves between said first position and said second position;