US5848583A
Expired / Lapsed
US
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Determining fuel injection pressure
Assignee: Ford Global Technologies LLC
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Filing: 1994-05-03
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Granted: 1998-12-15
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Expires: 2014-05-03
Abstract
Abstract This invention includes selecting a desired pressure for fuel injection in an internal combustion engine. The selection improves control of fuel injection by keeping the fuel in the fuel rail in a liquid state and by keeping the fuel injectors in an operating region where fuel injector fuel flow is less sensitive to changes in fuel injector pulse width.
Inventors
- 👤 James Craig Smith
- 👤 Darwin Allen Becker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:14
CPC Classifications
F; F02; F02M; F02M37/00; F02M37/20
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
118 words
A method of determining a desired pressure across fuel injectors of an internal combustion engine having a fuel rail coupled to the fuel injectors which have fuel flow curves relating desired fuel mass to be metered into the engine and fuel injector pulse width, including the steps of: determining a first fuel injection pressure required to keep fuel in the fuel rail liquid; determining a second fuel injection pressure to keep the fuel injectors operating in a low-sensitivity region of their fuel flow curve; and selecting the larger of the first and second fuel injection pressures as the desired fuel injection pressure to be maintained so as to provide liquid fuel at a minimum absolute fuel injection pressure.
Claim 2
Independent Claim
118 words
A method of determining a desired pressure across fuel injectors of an internal combustion engine having a fuel rail coupled to the fuel injectors which have fuel flow curves relating desired fuel mass to be metered into the engine and fuel injector pulse width, including the steps of: determining a first fuel injection pressure required to keep fuel in the fuel rail liquid; determining a second fuel injection pressure to keep the fuel injectors operating in a low-sensitivity region of their fuel flow curve; and selecting the larger of the first and second fuel injection pressures as the desired fuel injection pressure to be maintained so as to provide liquid fuel at a minimum absolute fuel injection pressure.
Claim 3
Dependent Claim
90 words
A method as recited in claim 1 wherein the step of determining a first fuel injection pressure includes the steps of: determining the relationship between the fuel rail temperature and the rail pressure needed to keep the fuel liquid; determining the fuel rail temperature; determining a fuel rail pressure needed to keep the fuel in the fuel rail liquid; and comparing fuel rail pressure to the manifold absolute pressure so as to determine a fuel injector pressure differential needed to maintain the fuel in the fuel line as a liquid.
Claim 4
Dependent Claim
60 words
A method as recited in claim 1 wherein determining the second fuel injection pressure includes the steps of: storing the relationship between the fuel mass and a pressure differential at a low sensitivity fuel injection operating point; determining the desired mass of fuel to be injected; and determining the desired pressure differential at a low sensitivity fuel injector operating point.
Claim 5
Dependent Claim
42 words
A method as recited in claim 2 wherein the step of comparing fuel rail pressure to the manifold absolute pressure includes the step of summing the manifold absolute pressure as a negative input and the fuel rail pressure as a positive input.
Claim 6
Independent Claim
103 words
An apparatus for determining a desired pressure across fuel injectors of an internal combustion engine having a fuel rail coupled to the fuel injectors, said apparatus including: means for determining a first fuel injection pressure required to keep fuel in the fuel rail liquid; means for determining a second fuel injection pressure to keep the fuel injectors operating in a low-sensitivity region of their fuel flow curve; and means for selecting the larger of the first and second fuel injection pressures as the desired fuel injection pressure to be maintained so as to provide liquid fuel at a minimum absolute fuel injection pressure.
Claim 7
Independent Claim
103 words
An apparatus for determining a desired pressure across fuel injectors of an internal combustion engine having a fuel rail coupled to the fuel injectors, said apparatus including: means for determining a first fuel injection pressure required to keep fuel in the fuel rail liquid; means for determining a second fuel injection pressure to keep the fuel injectors operating in a low-sensitivity region of their fuel flow curve; and means for selecting the larger of the first and second fuel injection pressures as the desired fuel injection pressure to be maintained so as to provide liquid fuel at a minimum absolute fuel injection pressure.
Claim 8
Dependent Claim
93 words
An apparatus as recited in claim 5 wherein said means for determining a first fuel injection pressure includes: means for determining the relationship between the fuel rail temperature and the rail pressure needed to keep the fuel liquid; means for determining the fuel rail temperature; determining a fuel rail pressure needed to keep the fuel in the fuel rail liquid; and means for comparing fuel rail pressure to the manifold absolute pressure so as to determine a fuel injector pressure differential needed to maintain the fuel in the fuel line as a liquid.
Claim 9
Dependent Claim
64 words
An apparatus in claim 5 wherein said means for determining the second fuel injection pressure includes: means for storing the relationship between the fuel mass and a pressure differential at a low sensitivity fuel injection operating point; means for determining the desired mass of fuel to be injected; and means for determining the desired pressure differential at a low sensitivity fuel injector operating point.
Claim 10
Dependent Claim
41 words
An apparatus as recited in claim 6 wherein said means for comparing fuel rail pressure to the manifold absolute pressure includes means for summing the manifold absolute pressure as a negative input and the fuel rail pressure as a positive input.
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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) | 2001-12-14 | 2002-06-15 | 2002-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-14 | 2006-06-15 | 2006-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-14 | 2010-06-15 | 2010-12-15 | $7700.00 | Window Closed / Lapsed |