EP0521545A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for diagnosing faults in engine air intake valve
Assignee: Motors Liquidation Co
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Filing: 1992-06-11
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Granted: —
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Expires: 2012-06-11
Abstract
Abstract A system is disclosed for diagnosing faulty check valve operation in an internal combustion engine (10) having a back flow preventing check valve (32) positioned in each intake air passage (26) leading to an engine cylinder (16). The system measures the pressure in the engine air induction system (12), upstream of each check valve (32) and downstream from an air intake throttle valve (30). The system produces an indication of faulty check valve operation when an abnormal fluctuation in the measured pressure is detected. Preferably, the diagnostic function is performed when the engine (10) operates in a defined mode, at idle speeds with light engine loading, where the pressure differential appearing across each check valve (32) is essentially maximized. The engine cylinder (16) associated with a faulty check valve (32) is identified based upon the sensed rotational position of the engine (10) when an abnormal fluctuation in pressure is detected.
Inventors
- 👤 Richard Stephen Davis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:33
CPC Classifications
G; G01; G01M; G01M15/00; G01M15/02; F; F02; F02B; F02B29/00; F02B29/02; F02B77/00; F02B77/08; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
153 words
Apparatus for diagnosing the state of operation of a check valve of an internal combustion engine, which internal combustion engine comprises at least one engine cylinder (16), an air induction system (12) including a throttle valve (30) for regulating air flow into the engine (10) and an air passage (26) disposed between the throttle valve and the or each engine cylinder, the or each air passage including a check valve (32) disposed therein for allowing air flow in a direction towards its associated cylinder and for preventing back flow in the opposite direction; the apparatus comprising a pressure sensor (44,34) for measuring the pressure in the air induction system between the or each check valve and the throttle valve, processing means (34) for detecting abnormal fluctuations in the measured pressure, and a fault indicator (34,46) for indicating the occurrence of a fault in response to a detected abnormal fluctuation in the measured pressure.
Claim 2
Dependent Claim
42 words
Apparatus according to claim 1, comprising control means (34,38,40,30) for enabling the detection of abnormal fluctuations in the measured pressure only when the engine is determined to be operating substantially at idle and when the engine load is below a predetermined load.
Claim 3
Dependent Claim
58 words
Apparatus according to claim 1 or 2, comprising engine position sensing means (34,40,42) for determining the rotational position of the engine on occurrence of an abnormal fluctuation in the measured pressure; and cylinder indentifying means (34,40,42) for identifying the cylinder associated with the abnormal fluctuation in the measured pressure on the basis of the determined engine rotational position.
Claim 4
Dependent Claim
33 words
Apparatus according to claim 1, 2 or 3, wherein the processing means (34) is adapted to obtain a plurality of samples of the measured air pressure over more than one complete engine cycle.
Claim 5
Dependent Claim
63 words
Apparatus according to any one of claims 1 to 4, wherein the processing means (34) is adapted to obtain a peak value associated with the measured pressure in the induction system to compare the peak value with a predetermined threshold value, and to determine that an abnormal fluctuation in the measured air pressure has occurred when the peak value exceeds the threshold value.
Claim 6
Dependent Claim
53 words
Apparatus according to claim 5, wherein the processing means (34) is adapted to obtain a plurality of samples of the measured pressure so as to produce a set of sampled pressure values, and to select a largest value from among the set of sampled pressure values, the largest value forming the peak value.
Claim 7
Dependent Claim
67 words
Apparatus according to any one of claims 1 to 4, wherein the processing means (34) is adapted to obtain a peak-to-peak value associated with the magnitude of the measured pressure in the air induction system, to compare the peak-to-peak value with a predetermined threshold value, and to determine that an abnormal fluctuation in the measured air pressure has occurred when the peak-to-peak value exceeds the threshold value.
Claim 8
Dependent Claim
64 words
Apparatus according to claim 7, wherein the processing means (34) is adapted to obtain a plurality of samples of the measured pressure so as to produce a set of sampled pressure values, to select a largest value and a smallest value from among the set of sampled pressure values, and to subtract the smallest value from the largest value, thereby obtaining the peak-to-peak value.
Claim 9
Dependent Claim
27 words
Apparatus according to any preceding claim, wherein the fault indicator (34,46) is adapted to indicate a fault on the occurrence of a predetermined number of abnormal fluctuations.
References Cited (Backward Citations)
No citation records indexed.
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