US5950606A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for diagnosing fuel supply system of internal combustion engine
Assignee: Denso Corp
•
Filing: 1998-07-08
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Granted: 1999-09-14
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Expires: 2018-07-08
Abstract
Abstract In an engine fuel supply system, the difference between the actual and target air-fuel ratios, an air-fuel ratio feedback correction coefficient and a learned correction amount are added as a parameter for diagnosing the fuel supply system. The diagnostic parameter is smoothed and the smoothed value is compared with a diagnosis reference value, thereby detecting a malfunction in the fuel supply system. Even if the learned correction amount is not updated, the malfunction in the fuel supply system can be promptly detected from the difference between the actual and target air-fuel ratios and the air-fuel ratio correction coefficient. The diagnosis reference value is determined variably in accordance with engine operating parameters such as the amount of intake air.
Inventors
- 👤 Hisashi Iida
- 👤 Shujiro Morinaga
- 👤 Hidenobu Muto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:59
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/22; F02D41/0025; F02D41/003; F02D41/0032; F02D41/0035; F02D41/0037; F02D41/02; F02D41/14; F02D41/1401; F02D41/1438; F02D41/1493; F02D41/1495; F02D41/24; F02D41/2406; F02D41/2425; F02D41/2429; F02D41/2451; F02D41/2454; F02D41/2458; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
198 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; diagnosing means for diagnosing a fuel supply system including the fuel injection system on a basis using all three parameters of (a) a difference between the actual air-fuel ratio and the target air-fuel ration, (b) the feedback correction amount, and (c) the learned correction amount.
Claim 2
Independent Claim
198 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; diagnosing means for diagnosing a fuel supply system including the fuel injection system on a basis using all three parameters of (a) a difference between the actual air-fuel ratio and the target air-fuel ration, (b) the feedback correction amount, and (c) the learned correction amount.
Claim 3
Dependent Claim
34 words
A system as in claim 1 further comprising: diagnosis inhibiting means for inhibiting the diagnosis means from its diagnosis operation when the air-fuel ratio feedback means is disabled to set the feedback correction amount.
Claim 4
Independent Claim
234 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; and diagnosing means for diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosing means calculates a sum of the difference between the actual air-fuel ratio and the target air fuel ratio, the feedback correction amount and the learned correction amount, and diagnoses the fuel supply system on the basis of the sum.
Claim 5
Independent Claim
234 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; and diagnosing means for diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosing means calculates a sum of the difference between the actual air-fuel ratio and the target air fuel ratio, the feedback correction amount and the learned correction amount, and diagnoses the fuel supply system on the basis of the sum.
Claim 6
Dependent Claim
26 words
A system as in claim 3, wherein: the diagnosing means smoothes the sum and diagnoses the fuel supply system on the basis of the smoothed value.
Claim 7
Independent Claim
216 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; and diagnosing means for diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosis means sets a diagnosis reference value variably on the basis of an engine operating state for diagnosing the fuel supply system.
Claim 8
Independent Claim
216 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; and diagnosing means for diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosis means sets a diagnosis reference value variably on the basis of an engine operating state for diagnosing the fuel supply system.
Claim 9
Independent Claim
262 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; and diagnosing means for diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; a fuel evaporation gas purge system for adsorbing a fuel evaporation gas from a fuel tank and introducing the fuel evaporation gas into an intake system of the internal combustion engine; and diagnosis inhibiting means for inhibiting the diagnosis of the fuel supply system when the concentration of the fuel evaporation gas introduced from the fuel evaporation gas purge system into the intake system is higher than a predetermined value.
Claim 10
Independent Claim
262 words
A system for diagnosing a fuel supply system of an internal combustion engine, said system comprising: air-fuel ratio detecting means for detecting an actual air-fuel ratio of an exhaust gas; basic fuel injection amount setting means for setting a basic fuel injection amount on the basis of an engine operating state; air-fuel ratio feedback means for setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning means for learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; required fuel injection amount setting means for setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; a fuel injection system for injecting fuel on the basis of the required fuel injection amount; and diagnosing means for diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; a fuel evaporation gas purge system for adsorbing a fuel evaporation gas from a fuel tank and introducing the fuel evaporation gas into an intake system of the internal combustion engine; and diagnosis inhibiting means for inhibiting the diagnosis of the fuel supply system when the concentration of the fuel evaporation gas introduced from the fuel evaporation gas purge system into the intake system is higher than a predetermined value.
Claim 11
Independent Claim
163 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating state; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; diagnosing a fuel supply system including the fuel injection system on a basis using all three parameters of (a) a difference between the actual air-fuel ratio and the target air-fuel ratio, (b) the feedback correction amount, and (c) the learned correction amount.
Claim 12
Independent Claim
163 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating state; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; diagnosing a fuel supply system including the fuel injection system on a basis using all three parameters of (a) a difference between the actual air-fuel ratio and the target air-fuel ratio, (b) the feedback correction amount, and (c) the learned correction amount.
Claim 13
Dependent Claim
29 words
A method as in claim 7 further comprising: inhibiting the diagnosis step from its diagnosis operation when the air-fuel ratio feedback is disabled to set the feedback correction amount.
Claim 14
Independent Claim
200 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating sate; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; and diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosing step includes calculating a sum of the difference between the actual air-fuel ratio and the target air fuel ratio, the feedback correction amount and the learned correction amount, and diagnosing the fuel supply system on the basis of the sum.
Claim 15
Independent Claim
200 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating sate; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; and diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosing step includes calculating a sum of the difference between the actual air-fuel ratio and the target air fuel ratio, the feedback correction amount and the learned correction amount, and diagnosing the fuel supply system on the basis of the sum.
Claim 16
Dependent Claim
26 words
A method as in claim 9, wherein: the diagnosing step smoothes the sum and diagnoses the fuel supply system on the basis of the smoothed value.
Claim 17
Independent Claim
181 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating state; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; and diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosis step sets a diagnosis reference value variably on the basis of an engine operating state for diagnosing the fuel supply system.
Claim 18
Independent Claim
181 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating state; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; and diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; wherein the diagnosis step sets a diagnosis reference value variably on the basis of an engine operating state for diagnosing the fuel supply system.
Claim 19
Independent Claim
216 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating sate; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; and diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; absorbing a fuel evaporation gas from a fuel tank and introducing the fuel evaporation gas into an intake system of the internal combustion engine; and inhibiting the diagnosis of the fuel supply system when the concentration of the fuel evaporation gas introduced from the fuel evaporation gas purge system into the intake system is higher than a predetermined value.
Claim 20
Independent Claim
216 words
A method for diagnosing a fuel supply system of an internal combustion engine, said method comprising: detecting an actual air-fuel ratio of an exhaust gas; setting a basic fuel injection amount on the basis of an engine operating sate; setting a feedback correction amount used for correcting a deviation of the actual air-fuel ratio from a target air-fuel ratio; learning a correction amount used for correcting the deviation of the actual air-fuel ratio from the target air-fuel ratio and updating and storing the learned correction amount; setting a required fuel injection amount on the basis of the basic fuel injection amount, the learned correction amount, and the feedback correction amount; injecting fuel on the basis of the required fuel injection amount; and diagnosing a fuel supply system including the fuel injection system on the basis of a difference between the actual air-fuel ratio and the target air-fuel ratio, the feedback correction amount and the learned correction amount; absorbing a fuel evaporation gas from a fuel tank and introducing the fuel evaporation gas into an intake system of the internal combustion engine; and inhibiting the diagnosis of the fuel supply system when the concentration of the fuel evaporation gas introduced from the fuel evaporation gas purge system into the intake system is higher than a predetermined value.
Claim 21
Independent Claim
86 words
A method for diagnosing abnormalities in an internal combustion engine fuel supply system, said method comprising: generating a first signal representing the difference between an actual air-fuel ratio and a target air-fuel ratio for the engine; generating a second signal representing a feedback correction value for the target air-fuel ratio; generating a third signal representing a learned correction value for the target air-fuel ratio; and using each of said first, second and third signals to diagnose the existence of an abnormality in the fuel supply system.
Claim 22
Independent Claim
86 words
A method for diagnosing abnormalities in an internal combustion engine fuel supply system, said method comprising: generating a first signal representing the difference between an actual air-fuel ratio and a target air-fuel ratio for the engine; generating a second signal representing a feedback correction value for the target air-fuel ratio; generating a third signal representing a learned correction value for the target air-fuel ratio; and using each of said first, second and third signals to diagnose the existence of an abnormality in the fuel supply system.
Claim 23
Dependent Claim
27 words
A method as in claim 13 wherein said using step includes diagnosing the fuel supply system based on the sum of said first, second and third signals.
Claim 24
Dependent Claim
26 words
A method as in claim 14 wherein said using step smoothes said sum and diagnoses the fuel supply system based on the thus smoothed sum value.
Claim 25
Dependent Claim
32 words
A method as in claim 13 wherein said using step uses a reference value to diagnose the fuel supply system which reference value changes as a function of an engine operating state.
Claim 26
Dependent Claim
32 words
A method as in claim 13 wherein: said diagnosis step is inhibited when previously adsorbed evaporated fuel is being returned to an engine intake in a concentration higher than a predetermined value.
Claim 27
Dependent Claim
30 words
A method as in claim 13 wherein: said using step is temporarily inhibited in response to temporary inhibition of the generation of said second signal due to engine operating conditions.
Claim 28
Dependent Claim
93 words
Apparatus for diagnosing abnormalities in an internal combustion engine fuel supply system, said apparatus comprising: means for generating a first signal representing the difference between an actual air-fuel ratio and a target air-fuel ratio for the engine; means for generating a second signal representing a feedback correction value for the target air-fuel ratio, means for generating a third signal representing a learned correction value for the target air-fuel ratio; and means for using each of said first, second and third signals to diagnose the existence of an abnormality in the fuel supply system.
Claim 29
Dependent Claim
93 words
Apparatus for diagnosing abnormalities in an internal combustion engine fuel supply system, said apparatus comprising: means for generating a first signal representing the difference between an actual air-fuel ratio and a target air-fuel ratio for the engine; means for generating a second signal representing a feedback correction value for the target air-fuel ratio, means for generating a third signal representing a learned correction value for the target air-fuel ratio; and means for using each of said first, second and third signals to diagnose the existence of an abnormality in the fuel supply system.
Claim 30
Dependent Claim
29 words
Apparatus as in claim 19 wherein said means for using includes means for diagnosing the fuel supply system based on the sum of said first, second and third signals.
Claim 31
Dependent Claim
30 words
Apparatus as in claim 20 wherein said means for using includes means for smoothing said sum and for diagnosing the fuel supply system based on the thus smoothed sum value.
Claim 32
Dependent Claim
32 words
Apparatus as in claim 19 wherein said means for using uses a reference value to diagnose the fuel supply system which reference value changes as a function of an engine operating state.
Claim 33
Dependent Claim
36 words
Apparatus as in claim 19 wherein: said means for using includes means for inhibiting said diagnosis when previously adsorbed evaporate fuel is being returned to an engine intake in a concentration higher than a predetermined value.
Claim 34
Dependent Claim
31 words
Apparatus as in claim 19 wherein: said means for using is temporarily inhibited in response to temporary inhibition of the means for generating said second signal due to engine operating conditions.
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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) | 2002-09-13 | 2003-03-15 | 2003-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-13 | 2007-03-15 | 2007-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-13 | 2011-03-15 | 2011-09-14 | $7700.00 | Window Closed / Lapsed |