US5203870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for detecting abnormal state of evaporative emission-control system
Assignee: Toyota Motor Corp
•
Filing: 1991-06-26
•
Granted: 1993-04-20
•
Expires: 2011-06-26
Abstract
Abstract In an evaporative emission-control system having a canister for trapping a fuel-vapor evaporated from the fuel tank and a purge control valve for executing a purging, an amount of fuel-vapor trapped in the canister is measured while the engine is stopped or in an idle state. The trapped fuel-vapor is purged from the canister and mixed with an air-fuel mixture when the amount of fuel-vapor trapped in the canister is sufficient for diagnosis while the vehicle is running in a predetermined driving condition. In this purge operation, a concentration of a vapor-laden air from the canister is measured and the occurrence of an abnormal state of the evaporative emission-control system is determined when a change of the concentration of the vapor-laden air after the purging is less than a predetermined value.
Inventors
- 👤 Nobuaki Kayanuma
- 👤 Kenichi Uchida
- 👤 Takayuki Otsuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:36
CPC Classifications
F; F02; F02M; F02M25/00; F02M25/08; F02M25/0809; F02M2025/0845
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
221 words
A method of detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising the steps of: detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which fuel-vapor flows into the canister; purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; detecting a concentration of a vapor-laden air from the canister when the purging is executed; and determining the occurrence of an abnormal state of the evaporate emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel-vapor trapped in the canister is executed, and a change of the concentration of the vapor-laden air from the canister before and after the purging is less than a predetermined value.
Claim 2
Independent Claim
221 words
A method of detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising the steps of: detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which fuel-vapor flows into the canister; purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; detecting a concentration of a vapor-laden air from the canister when the purging is executed; and determining the occurrence of an abnormal state of the evaporate emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel-vapor trapped in the canister is executed, and a change of the concentration of the vapor-laden air from the canister before and after the purging is less than a predetermined value.
Claim 3
Dependent Claim
39 words
A method as set forth in claim 1, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 4
Dependent Claim
39 words
A method as set forth in claim 1, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 5
Dependent Claim
39 words
A method as set forth in claim 1, further comprising the step of prohibiting an execution of a diagnosis of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is less than a predetermined amount.
Claim 6
Dependent Claim
71 words
A method as set forth in claim 4, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting a time for which the purging is not executed, and prohibiting a diagnosis of the evaporative emission-control system when a difference between the time for which the purging is not executed and a time for which the purging is executed is less than a predetermined time.
Claim 7
Dependent Claim
39 words
A method as set forth in claim 5, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 8
Independent Claim
226 words
A method of detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising the steps of: detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which fuel-vapor flows into the canister; purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; detecting a concentration of a vapor-laden air from the canister when the purging is executed; and determining the occurrence of an abnormal state of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel-vapor trapped in the canister is executed, and the detected concentration of a vapor-laden air is smaller than the calculated concentration of a vapor-laden air in accordance with the amount of fuel-vapor trapped in the canister.
Claim 9
Independent Claim
226 words
A method of detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising the steps of: detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which fuel-vapor flows into the canister; purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; detecting a concentration of a vapor-laden air from the canister when the purging is executed; and determining the occurrence of an abnormal state of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel-vapor trapped in the canister is executed, and the detected concentration of a vapor-laden air is smaller than the calculated concentration of a vapor-laden air in accordance with the amount of fuel-vapor trapped in the canister.
Claim 10
Dependent Claim
39 words
A method as set forth in claim 7, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 11
Dependent Claim
39 words
A method as set forth in claim 7, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 12
Dependent Claim
39 words
A method as set forth in claim 7, further comprising the step of prohibiting an execution of a diagnosis of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is less than a predetermined amount.
Claim 13
Dependent Claim
71 words
A method as set forth in claim 10, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting a time for which the purging is not executed, and prohibiting a diagnosis of the evaporative emission-control system when a difference between the time for which the purging is not executed and a time for which the purging is executed is less than a predetermined time.
Claim 14
Dependent Claim
39 words
A method as set forth in claim 11, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 15
Independent Claim
226 words
An apparatus for detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising: means for detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which fuel-vapor flows into the canister; means for purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; means for detecting a concentration of a vapor-laden air from the canister when the purging is executed; and means for determining the occurrence of an abnormal state of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel-vapor trapped in the canister is executed, and a change of the concentration of the vapor-laden air from the canister before and after the purging is less than a predetermined value.
Claim 16
Independent Claim
226 words
An apparatus for detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising: means for detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which fuel-vapor flows into the canister; means for purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; means for detecting a concentration of a vapor-laden air from the canister when the purging is executed; and means for determining the occurrence of an abnormal state of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel-vapor trapped in the canister is executed, and a change of the concentration of the vapor-laden air from the canister before and after the purging is less than a predetermined value.
Claim 17
Dependent Claim
39 words
An apparatus as set forth in claim 13, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 18
Dependent Claim
39 words
An apparatus as set forth in claim 13, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 19
Dependent Claim
38 words
An apparatus as set forth in claim 13, further comprising means for prohibiting an execution of a diagnosis of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is less than a predetermined amount.
Claim 20
Dependent Claim
71 words
An apparatus as set forth in claim 16, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting a time for which the purging is not executed, and prohibiting a diagnosis of the evaporative emission-control system when a difference between the time for which the purging is not executed and a time for which the purging is executed is less than a predetermined time.
Claim 21
Dependent Claim
39 words
An apparatus as set forth in claim 17, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 22
Independent Claim
233 words
An apparatus for detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising: means for detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which the fuel-vapor flows into the canister; means for purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; means for detecting a concentration of a vapor-laden air from the canister when the purging is executed; and means for determining the occurrence of an abnormal state of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel vapor trapped in the canister is executed, and the detected concentration of a vapor-laden air is smaller than the calculated concentration of a vapor-laden air in accordance with the amount of fuel-vapor trapped in the canister.
Claim 23
Independent Claim
233 words
An apparatus for detecting an abnormal state of an evaporative emission-control system in which a fuel-vapor evaporated from the fuel tank is temporarily trapped in a canister when an internal combustion engine is stopped or in an idle state, the trapped fuel-vapor is purged from the canister by a vacuum in a air-intake passage of the engine, and the purged fuel-vapor is mixed with an air-fuel mixture to be burned in a combustion chamber when a vehicle is running in a predetermined driving condition, comprising: means for detecting an amount of fuel-vapor trapped in the canister, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting the time period for which the fuel-vapor flows into the canister; means for purging the fuel-vapor trapped in the canister and mixing the purged fuel-vapor with the air-fuel mixture in an air-intake passage; means for detecting a concentration of a vapor-laden air from the canister when the purging is executed; and means for determining the occurrence of an abnormal state of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is more than a predetermined amount, purging of the fuel vapor trapped in the canister is executed, and the detected concentration of a vapor-laden air is smaller than the calculated concentration of a vapor-laden air in accordance with the amount of fuel-vapor trapped in the canister.
Claim 24
Dependent Claim
39 words
An apparatus as set forth in claim 19, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 25
Dependent Claim
39 words
An apparatus as set forth in claim 19, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
Claim 26
Dependent Claim
38 words
An apparatus as set forth in claim 19, further comprising means for prohibiting an execution of a diagnosis of the evaporative emission-control system when the amount of fuel-vapor trapped in the canister is less than a predetermined amount.
Claim 27
Dependent Claim
71 words
An apparatus as set forth in claim 22, wherein the detection of the amount of fuel-vapor trapped in the canister is carried out by counting a time for which the purging is not executed, and prohibiting a diagnosis of the evaporative emission-control system when a difference between the time for which the purging is not executed and a time for which the purging is executed is less than a predetermined time.
Claim 28
Dependent Claim
39 words
An apparatus as set forth in claim 23, wherein the detection of the concentration of the vapor-laden air from the canister is carried out by a fuel gas sensor disposed downstream of a purge port in the air-intake passage.
References Cited (Backward Citations)
US4318383A
Cited
US4338905A
Cited
JPS58185966A
Cited
US4867126A
Cited
US4671107A
Cited
JPS63186955A
Cited
US4846135A
Cited
JPH01125552A
Cited
US4901702A
Cited
JPH0226754A
Cited
US4949695A
Cited
US4962744A
Cited
JPH02130256A
Cited
JPH02136558A
Cited
US5067469A
Cited
US5021071A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-19 | 1996-10-19 | 1997-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-19 | 2000-10-19 | 2001-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-19 | 2004-10-19 | 2005-04-20 | $7700.00 | Window Closed / Lapsed |