US5404855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable displacement high pressure pump for fuel injection systems
Assignee: Cummins Engine IP Inc
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Filing: 1994-06-30
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Granted: 1995-04-11
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Expires: 2014-06-30
Abstract
Abstract A variable displacement high pressure pump having a plurality of high pressure pumping units which receive fuel from a low pressure fuel pump. A rotary cam-driven roller tappet, for producing pumping displacement of the pumping plunger of a respective pumping element, is connected to the pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle. As a result, the capacity of the pumping chamber can be limited to an extent that is less than the full stroke achievable by the pumping plunger being retracted to the maximum extent which is permitted by the driving cam. In this way, the quantity of fuel to be pressurized and injected into the common rail does not have to be determined by a cutting-off of a spilling flow of excess metered fuel during the compression stroke of the pumping plunger, so that a low pressure solenoid valve can be used, in the case of time-stroke and time-pressure metering, and no solenoid is required to control metering in the case of pressure-time metering.
Inventors
- 👤 Bai-Mao Yen
- 👤 Lester L. Peters
- 👤 Julius P. Perr
- 👤 Bryan W. Swank
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:27
CPC Classifications
F; F04; F04B; F04B9/00; F04B9/02; F04B9/06; F02; F02M; F02M41/00; F02M41/16; F02M45/00; F02M45/02; F02M45/04; F02M45/12; F02M51/00; F02M55/00; F02M55/02; F02M55/025; F02M59/00; F02M59/20; F02M59/30; F02M59/34; F02M59/36; F02M59/44; F02M59/46; F02M59/466; F02M63/00; F02M63/0003; F02M63/0007; F02M63/0008; F02M63/02; F02M63/0225; F02D; F02D41/00; F02D41/22; F02D2041/224; F02D2041/225; F04B2205/00; F04B2205/05; F04B2205/15
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
186 words
A variable displacement high pressure pump for supplying fuel to a common rail fuel injection system having a plurality of fuel injectors connected to a common Eel supply rail, said high pressure pump comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to a common rail of a common rail fuel injection system; and wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle.
Claim 2
Dependent Claim
186 words
A variable displacement high pressure pump for supplying fuel to a common rail fuel injection system having a plurality of fuel injectors connected to a common Eel supply rail, said high pressure pump comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to a common rail of a common rail fuel injection system; and wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle.
Claim 3
Dependent Claim
192 words
A variable displacement high pressure pump according to claim 1, wherein, for metering of fuel into the pumping chamber on a time/stroke basis, said separated link connects said pumping plunger with said roller tappet via a link plunger that is articulated to the roller tappet; wherein a fuel supply line having a check valve at the fuel supply inlet of each of the pumping elements is connected to the outlet of said low pressure pump for supplying a first flow of fuel from the low pressure pump to each pumping chamber; wherein a single solenoid valve is provided for controlling a second flow of fuel from the outlet of the low pressure pump to metering orifices of all of said plurality of high pressure pumping elements, each .of said metering orifices being located at an inlet to a portion of said bore that is disposed between the pumping plunger and the link plunger of a respective one of said plurality of high pressure pumping elements; and wherein said portion of the bore between the pumping plunger and the link plunger is communicated with a drain port during part of each pumping cycle.
Claim 4
Dependent Claim
26 words
A variable displacement high pressure pump according to claim 2, wherein said separated link comprises a spring acting between the pumping plunger and the link plunger.
Claim 5
Dependent Claim
234 words
A variable displacement high pressure pump for a common rail fuel injection .system comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to a common rail of a fuel injection system; wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller, tappet during at least a portion of each pumping cycle; and wherein, for metering of fuel into the pumping chamber on a time-pressure basis, a single solenoid valve is provided for controlling a time metered flow of a constant-pressure supply of fuel from the outlet of the low pressure pump to the pumping chamber of each of the pumping elements, a check valve being located at each fuel supply inlet for preventing a return flow of fuel from the pumping chamber.
Claim 6
Dependent Claim
234 words
A variable displacement high pressure pump for a common rail fuel injection .system comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to a common rail of a fuel injection system; wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller, tappet during at least a portion of each pumping cycle; and wherein, for metering of fuel into the pumping chamber on a time-pressure basis, a single solenoid valve is provided for controlling a time metered flow of a constant-pressure supply of fuel from the outlet of the low pressure pump to the pumping chamber of each of the pumping elements, a check valve being located at each fuel supply inlet for preventing a return flow of fuel from the pumping chamber.
Claim 7
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 4, wherein said separated link comprises a free-floating relationship between the pumping plunger and the roller tappet in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 8
Dependent Claim
101 words
A variable displacement high pressure pump according to claim 1, wherein, for metering of fuel into the pumping chamber on a pressure-time basis, a variable orifice is provided for controlling the pressure of a pressure metered flow of a supply of fuel from the outlet of the low pressure pump to the pumping chamber of each of the pumping elements during a constant time window, a check valve being located at each fuel supply inlet for preventing a return flow of fuel from the pumping chamber and a flow control orifice being located at said inlet, downstream of said check valve.
Claim 9
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 6, wherein said separated link comprises a free-floating relationship between the pumping plunger and the roller tappet in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 10
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 1, wherein said separated link comprises a free-floating relationship between the pumping plunger and the roller tappet in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 11
Dependent Claim
137 words
A variable displacement high pressure pump for a fuel injection system comprising a constant low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to a fuel injection system; and wherein a single solenoid valve controls fuel flow from said low pressure pump to said plurality of high pressure pumping elements at different time intervals.
Claim 12
Dependent Claim
137 words
A variable displacement high pressure pump for a fuel injection system comprising a constant low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to a fuel injection system; and wherein a single solenoid valve controls fuel flow from said low pressure pump to said plurality of high pressure pumping elements at different time intervals.
Claim 13
Dependent Claim
133 words
A variable displacement high pressure pump according to claim 9, wherein a fuel supply line having a check valve at the fuel supply inlet of each of the pumping elements is connected to the outlet of said low pressure pump for supplying a first flow of fuel from the low pressure pump to each pumping chamber; wherein the single solenoid valve is provided in a second flow of fuel from the outlet of the low pressure pump to a metering orifice at an inlet to a portion of said bore that is disposed at an opposite side of said pumping plunger relative to said pumping chamber; and wherein said portion of the bore at the opposite side of the pumping plunger is communicated with a drain port during part of each pumping cycle.
Claim 14
Dependent Claim
57 words
A variable displacement high pressure pump according to claim 10, wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle.
Claim 15
Dependent Claim
71 words
A variable displacement high pressure pump according to claim 11, wherein said separated link connects said pumping plunger with said roller tappet via a link plunger that is articulated to the roller tappet; and wherein the portion of said bore that is disposed at the opposite side of the pumping plunger is formed between the pumping plunger and the link plunger of each of said plurality of high pressure pumping elements.
Claim 16
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 11, wherein said separated link comprises a free-floating relationship between the pumping plunger and the link plunger in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 17
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 9, wherein said separated link comprises a free-floating relationship between the pumping plunger and the link plunger in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 18
Dependent Claim
185 words
A variable displacement high pressure pump for supplying high pressure fuel to a high pressure fuel accumulator of a fuel injection system having a plurality of fuel injectors, said high pressure pump comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to said high pressure fuel accumulator of the fuel injection system; and wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle.
Claim 19
Dependent Claim
185 words
A variable displacement high pressure pump for supplying high pressure fuel to a high pressure fuel accumulator of a fuel injection system having a plurality of fuel injectors, said high pressure pump comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to said high pressure fuel accumulator of the fuel injection system; and wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle.
Claim 20
Dependent Claim
192 words
A variable displacement high pressure pump according to claim 15, wherein, for metering of fuel into the pumping chamber on a time/stroke basis, said separated link connects said pumping plunger with said roller tappet via a link plunger that is articulated to the roller tappet; wherein a fuel supply line having a check valve at the fuel supply inlet of each of the pumping elements is connected to the outlet of said low pressure pump for supplying a first flow of fuel from the low pressure pump to each pumping chamber; wherein a single solenoid valve is provided for controlling a second flow of fuel from the outlet of the low pressure pump to metering orifices of all of said plurality of high pressure pumping elements, each of said metering orifices being located at an inlet to a portion of said bore that is disposed between the pumping plunger and the link plunger of a respective one of said plurality of high pressure pumping elements; and wherein said portion of the bore between the pumping plunger and the link plunger is communicated with a drain port during part of each pumping cycle.
Claim 21
Dependent Claim
26 words
A variable displacement high pressure pump according to claim 16, wherein said separated link comprises a spring acting between the pumping plunger and the link plunger.
Claim 22
Dependent Claim
231 words
A variable displacement high pressure pump for a fuel injection system comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to an accumulator of a fuel injection system; wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle; and wherein, for metering of fuel into the pumping chamber on a time-pressure basis, a single solenoid valve is provided for controlling a time metered flow of a constant-pressure supply of fuel from the outlet of the low pressure pump to the pumping chamber of each of the pumping elements, a check valve being located at each fuel supply inlet for preventing a return flow of fuel from the pumping chamber.
Claim 23
Dependent Claim
231 words
A variable displacement high pressure pump for a fuel injection system comprising a low pressure pump having an outlet which is connected to a fuel supply inlet of each of a plurality of high pressure pumping elements; wherein each of the pumping elements has a pumping plunger that is mounted for reciprocation in a bore; wherein a variable volume pumping chamber, into which fuel from said low pressure pump is metered via said fuel supply inlet, is formed in said bore between an end of the pumping plunger and an outlet of the pumping element through which fuel pressurized by said pumping plunger is supplied to an accumulator of a fuel injection system; wherein a rotary cam-driven roller tappet for producing pumping displacement of the pumping plunger is connected to each pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle; and wherein, for metering of fuel into the pumping chamber on a time-pressure basis, a single solenoid valve is provided for controlling a time metered flow of a constant-pressure supply of fuel from the outlet of the low pressure pump to the pumping chamber of each of the pumping elements, a check valve being located at each fuel supply inlet for preventing a return flow of fuel from the pumping chamber.
Claim 24
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 18, wherein said separated link comprises a free-floating relationship between the pumping plunger and the roller tappet in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 25
Dependent Claim
101 words
A variable displacement high pressure pump according to claim 15, wherein, for metering of fuel into the pumping chamber on a pressure-time basis, a variable orifice is provided for controlling the pressure of a pressure metered flow of a supply of fuel from the outlet of the low pressure pump to the pumping chamber of each of the pumping elements during a constant time window, a check valve being located at each fuel supply inlet for preventing a return flow of fuel from the pumping chamber and a flow control orifice being located at said inlet, downstream of said check valve.
Claim 26
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 20, wherein said separated link comprises a free-floating relationship between the pumping plunger and the roller tappet in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
Claim 27
Dependent Claim
54 words
A variable displacement high pressure pump according to claim 15, wherein said separated link comprises a free-floating relationship between the pumping plunger and the roller tappet in which said tappet is connected to the pumping plunger, in an abutting manner, only during a pumping phase for pressurizing and injecting fuel from said pumping chamber.
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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) | 1998-04-10 | 1998-10-10 | 1999-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-10 | 2002-10-10 | 2003-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-10 | 2006-10-10 | 2007-04-11 | $7700.00 | Window Closed / Lapsed |