US5385134A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for monitoring leakage into exhaust lines
Assignee: Schaeffler Engineering GmbH
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Filing: 1993-06-11
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Granted: 1995-01-31
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Expires: 2013-06-11
Abstract
Abstract A system for monitoring suction leakage of external air into the exhaust gas path of an internal combustion engine during intermittent reduced pressure phases of the engine, during operation, includes an oxygen concentration sensing lambda probe arranged in the path. The probe issues an output signal having a reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of such oxygen concentration during the reduced pressure phases. The output signal is fed to a control device which generates an error signal when that amplitude exceeds a predetermined threshold level indicative of suction entry of external air into the path during a reduced pressure phase.
Inventors
- 👤 Harald Krohm
- 👤 Ludger Holscher
- 👤 Andreas Nithammer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:31
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/22; F01; F01N; F01N11/00; F02B; F02B77/00; F02B77/08; F02B77/085; F02B77/086; F02B77/088; F01N2550/00; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
164 words
In a method for monitoring the air/fuel mixture of an internal combustion engine having an exhaust gas path and arranged for air/fuel mixture fed engine operation including intermittent reduced pressure phases of the engine, during operation, in which the path undergoes periods of reduced pressure relative to the atmospheric pressure of external air, and using a lambda probe in the path for sensing the oxygen concentration in the exhaust gas and for issuing an output signal having a reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of the oxygen concentration during the reduced pressure phases, for controlling the engine operation by controlling the ratio of the air/fuel mixture fed to the engine, the improvement, comprising: monitoring the amplitude of the pulsation frequency component of the probe output signal, and generating an error signal upon said amplitude exceeding a predetermined threshold level indicative of atmospheric pressure external air suction leakage into the path during such reduced pressure phases of engine operation.
Claim 2
Dependent Claim
164 words
In a method for monitoring the air/fuel mixture of an internal combustion engine having an exhaust gas path and arranged for air/fuel mixture fed engine operation including intermittent reduced pressure phases of the engine, during operation, in which the path undergoes periods of reduced pressure relative to the atmospheric pressure of external air, and using a lambda probe in the path for sensing the oxygen concentration in the exhaust gas and for issuing an output signal having a reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of the oxygen concentration during the reduced pressure phases, for controlling the engine operation by controlling the ratio of the air/fuel mixture fed to the engine, the improvement, comprising: monitoring the amplitude of the pulsation frequency component of the probe output signal, and generating an error signal upon said amplitude exceeding a predetermined threshold level indicative of atmospheric pressure external air suction leakage into the path during such reduced pressure phases of engine operation.
Claim 3
Dependent Claim
19 words
Method of claim 1 wherein the pulsation frequency component is filtered out from the output signal for such monitoring.
Claim 4
Dependent Claim
198 words
Method for monitoring the air/fuel mixture of an internal combustion engine including intermittent reduced pressure phases of the engine, during operation, in which the exhaust gas path of the engine undergoes periods of reduced pressure relative to the atmospheric pressure of external air, for indicating suction leakage of external air into the path during such reduced pressure phases of the engine, during operation, comprising: using a sensing and signaling probe in the path for sensing the oxygen concentration in the exhaust gas and for issuing an output signal having a control amplitude and frequency component and a superimposed reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of the oxygen concentration in the path during such reduced pressure phases of the engine, during operation, for controlling the engine by controlling the ratio of the air/fuel mixture fed to the engine, and monitoring the amplitude of the pulsation frequency component of the probe output signal relative to a predetermined threshold level of said amplitude indicative of external air suction leakage into the path during such reduced pressure phases of the engine, during operation, and generating an error signal upon said amplitude exceeding the predetermined threshold level.
Claim 5
Dependent Claim
198 words
Method for monitoring the air/fuel mixture of an internal combustion engine including intermittent reduced pressure phases of the engine, during operation, in which the exhaust gas path of the engine undergoes periods of reduced pressure relative to the atmospheric pressure of external air, for indicating suction leakage of external air into the path during such reduced pressure phases of the engine, during operation, comprising: using a sensing and signaling probe in the path for sensing the oxygen concentration in the exhaust gas and for issuing an output signal having a control amplitude and frequency component and a superimposed reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of the oxygen concentration in the path during such reduced pressure phases of the engine, during operation, for controlling the engine by controlling the ratio of the air/fuel mixture fed to the engine, and monitoring the amplitude of the pulsation frequency component of the probe output signal relative to a predetermined threshold level of said amplitude indicative of external air suction leakage into the path during such reduced pressure phases of the engine, during operation, and generating an error signal upon said amplitude exceeding the predetermined threshold level.
Claim 6
Dependent Claim
31 words
Method of claim 3 wherein a three way catalytic converter is disposed operatively in the path, and the probe is arranged in the path immediately before the three way catalytic converter.
Claim 7
Dependent Claim
187 words
Monitoring apparatus, comprising: an internal combustion engine having an exhaust gas path and arranged for air/fuel mixture fed engine operation including intermittent reduced pressure phases of the engine, during operation, in which the path undergoes periods of reduced pressure relative to the atmospheric pressure of external air, and monitoring means for detecting external air suction leakage into the path, including a sensing and signaling probe arranged for sensing the oxygen concentration in the path and for issuing an output signal having a control amplitude and frequency component and a superimposed reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of such oxygen concentration in the path during such reduced pressure phases of the engine, during operation, and control means responsive to the output signal from the probe for controlling the engine by controlling the ratio of the air/fuel mixture fed to the engine and for generating an error signal upon said reduced pressure phase amplitude of said pulsation frequency component exceeding a predetermined threshold level indicative of external air suction leakage into the path during such reduced pressure phases of the engine, during operation.
Claim 8
Dependent Claim
187 words
Monitoring apparatus, comprising: an internal combustion engine having an exhaust gas path and arranged for air/fuel mixture fed engine operation including intermittent reduced pressure phases of the engine, during operation, in which the path undergoes periods of reduced pressure relative to the atmospheric pressure of external air, and monitoring means for detecting external air suction leakage into the path, including a sensing and signaling probe arranged for sensing the oxygen concentration in the path and for issuing an output signal having a control amplitude and frequency component and a superimposed reduced pressure phase pulsation frequency component of reduced pressure phase amplitude indicative of such oxygen concentration in the path during such reduced pressure phases of the engine, during operation, and control means responsive to the output signal from the probe for controlling the engine by controlling the ratio of the air/fuel mixture fed to the engine and for generating an error signal upon said reduced pressure phase amplitude of said pulsation frequency component exceeding a predetermined threshold level indicative of external air suction leakage into the path during such reduced pressure phases of the engine, during operation.
Claim 9
Dependent Claim
31 words
Apparatus of claim 5 wherein a three way catalytic converter is disposed operatively in the path, and the probe is arranged in the path immediately before the three way catalytic converter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-01-30 | 1998-08-01 | 1999-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-30 | 2002-08-01 | 2003-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-30 | 2006-08-01 | 2007-01-31 | $7700.00 | Window Closed / Lapsed |