Patent US5033443A successfully refreshed from Google Patents.
US5033443A
Expired / Lapsed
US
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Pilot injection device for fuel injection pump
Assignee: Denso Corp
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Filing: 1989-06-26
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Granted: 1991-07-23
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Expires: 2009-06-26
Abstract
Abstract A pilot injection device for a fuel injection pump has an accumulate piston movable in response to a fuel pressure from a pressurizing chamber of the fuel injection pump to cause a pilot injection prior to a main injection by the pump. The device is provided with a back-pressure chamber filled with fuel and having a volume variable by the movement of the accumulate piston. Air trapped in the back-pressure chamber can be removed therefrom through a hole to improve the operation characteristic of the pilot injection device.
Inventors
- 👤 Akira Kato
- 👤 Koji Nagata
- 👤 Zenji Kuwabara
- 👤 Terutada Kojima
- 👤 Takashi Yamaguchi
- 👤 Takaaki Ohashi
- 👤 Masato Hattori
- 👤 Noriyosi Toyoda
- 👤 Noriaki Kawai
- 👤 Teruo Sato
- 👤 Toshio Fujimura
- 👤 Tadashi Watanabe
- 👤 Mitsumasa Yamada
- 👤 Tadashi Fukuyama
- 👤 Takeshi Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:57
CPC Classifications
F; F02; F02M; F02M41/00; F02M41/08; F02M41/10; F02M41/12; F02M41/123; F02M41/125; F02M41/126; F02M45/00; F02M45/02; F02M45/04; F02M45/06
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
135 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in fuel pressure in said pressurizing chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein and being capable of controlling the movement of said accumulate piston; means for allowing air accumulated in said back pressure chamber to be removed, said allowing means comprising a through-hole connecting the interior of said back-pressure chamber to the outside thereof; means for opening and closing said through-hole, said opening and closing means comprising a detachable screw; and a stopper connected to said detachable screw for determining the maximum movement of said accumulate piston.
Claim 2
Dependent Claim
135 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in fuel pressure in said pressurizing chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein and being capable of controlling the movement of said accumulate piston; means for allowing air accumulated in said back pressure chamber to be removed, said allowing means comprising a through-hole connecting the interior of said back-pressure chamber to the outside thereof; means for opening and closing said through-hole, said opening and closing means comprising a detachable screw; and a stopper connected to said detachable screw for determining the maximum movement of said accumulate piston.
Claim 3
Dependent Claim
143 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in fuel pressure in said pressurizing chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein and being capable of controlling the movement of said accumulate piston; means for allowing air accumulated in said back-pressure chamber to be removed; a pressure pin connected to said accumulate piston; said cylinder accommodating a first stopper for limiting the movement of said accumulate piston and a second stopper for limiting the movement of said pressure pin; and the distance between said pressure pin and said second stopper being slightly greater than the distance between said accumulate piston and said first stopper.
Claim 4
Dependent Claim
143 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in fuel pressure in said pressurizing chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein and being capable of controlling the movement of said accumulate piston; means for allowing air accumulated in said back-pressure chamber to be removed; a pressure pin connected to said accumulate piston; said cylinder accommodating a first stopper for limiting the movement of said accumulate piston and a second stopper for limiting the movement of said pressure pin; and the distance between said pressure pin and said second stopper being slightly greater than the distance between said accumulate piston and said first stopper.
Claim 5
Dependent Claim
142 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in fuel pressure in said pressuring chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein, and being capable of controlling the movement of said accumulate piston; and means for allowing air accumulated in said back-pressure chamber to be removed; wherein said cylinder accommodates a first stopper for restricting the movement of said accumulate piston and a second stopper for restricting a pressure pin connected to said accumulate piston, wherein a distance between said pressure pin and said second stopper is set to be slightly larger than the distance between said accumulate piston and said first stopper.
Claim 6
Dependent Claim
142 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in fuel pressure in said pressuring chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein, and being capable of controlling the movement of said accumulate piston; and means for allowing air accumulated in said back-pressure chamber to be removed; wherein said cylinder accommodates a first stopper for restricting the movement of said accumulate piston and a second stopper for restricting a pressure pin connected to said accumulate piston, wherein a distance between said pressure pin and said second stopper is set to be slightly larger than the distance between said accumulate piston and said first stopper.
Claim 7
Dependent Claim
162 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in the fuel pressure in said pressurizing chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein and being capable of controlling the movement of said accumulate piston; a pressure pin connected to said accumulate piston; a first stopper defining a maximum stroke position of said accumulate piston; a second stopper defining a maximum stroke position of said pressure pin; means for allowing air accumulated in said back-pressure chamber to be removed therefrom, said allowing means comprising a through-hole which connects an inside of said back-pressure chamber to the outside thereof; and means for opening and closing said through-hole, said opening and closing means comprises a detachable screw, wherein said second stopper is secured to said screw.
Claim 8
Dependent Claim
162 words
A pilot injection device for a fuel injection pump, comprising: means forming a cylinder connected to a pressurizing chamber of said fuel injection pump; an accumulate piston slidably disposed in said cylinder and being movable in response to a rise in the fuel pressure in said pressurizing chamber; means defining therein a back-pressure chamber connected to said cylinder, filled with fuel therein and being capable of controlling the movement of said accumulate piston; a pressure pin connected to said accumulate piston; a first stopper defining a maximum stroke position of said accumulate piston; a second stopper defining a maximum stroke position of said pressure pin; means for allowing air accumulated in said back-pressure chamber to be removed therefrom, said allowing means comprising a through-hole which connects an inside of said back-pressure chamber to the outside thereof; and means for opening and closing said through-hole, said opening and closing means comprises a detachable screw, wherein said second stopper is secured to said screw.
Claim 9
Dependent Claim
27 words
A pilot injection device according to claim 3, wherein said allowing means comprises a through-hole which connects an inside of said back-pressure chamber to the outside thereof.
Claim 10
Dependent Claim
17 words
A pilot injection device according to claim 5, further including means for opening and closing said through-hole.
Claim 11
Dependent Claim
17 words
A pilot injection device according to claim 6, wherein said opening and closing means comprises detachable screw.
Claim 12
Dependent Claim
23 words
A pilot injection device according to claim 6, wherein said opening and closing means comprises a check valve openable by an external force.
Claim 13
Dependent Claim
21 words
A pilot injection device according to claim 6, wherein said opening and closing means comprises a blind cap detachable from outside.
Claim 14
Dependent Claim
40 words
A pilot injection device according to claim 3, wherein said cylinder forming means comprises a member detachably fastened to a high pressure resisting sealing member which is secured to said injection pump to keep said pressurizing chamber in sealed condition.
Claim 15
Dependent Claim
18 words
A pilot injection device according to claim 3, wherein said second stopper is formed in a hollow shape.
Claim 16
Dependent Claim
37 words
A pilot injection device according to claim 3, wherein a minimum diameter of said accumulate piston is smaller than a diameter of a surface of said second stopper at which said pressure pin contacts said second stopper.
Claim 17
Dependent Claim
26 words
A pilot injection device according to claim 3, further including means for restricting a flow of fuel generated due to the movement of said accumulate piston.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-22 | 1995-01-21 | 1995-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-22 | 1999-01-21 | 1999-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-22 | 2003-01-21 | 2003-07-23 | $7700.00 | Window Closed / Lapsed |