US5033443A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 00:40
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.
References Cited (Backward Citations)
US3456629A
Cited
FR2067883A5
Cited
JPS54112419A
Cited
US4469069A
Cited
EP0116168A2
Cited
US4530337A
Cited
US4625694A
Cited
JPS61106971A
Cited
GB2170557A
Cited
DE3541049A1
Cited
US4694810A
Cited
US4831991A
Cited
GB2186920A
Cited
JPS6321359A
Cited
US4840155A
Cited
US4831986A
Cited
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 |