Apparatus and method for diagnosing exhaust recirculation system in internal combustion engine
First Claim
1. An apparatus for diagnosing an exhaust gas recirculation system having exhaust gas recirculation control valve means interposed in an exhaust gas recirculation passage of an internal combustion engine so as to recirculate part of exhaust gas into a suction system of the engine in response to an EGR control signal, comprising:
- a) detecting means for detecting an engine driving condition;
b) combustion state related parameter measuring means for measuring a combustion state related parameter of at least one combustion chamber of engine cylinders;
c) combustion time duration measuring means for measuring a length of a combustion time duration in one combustion stroke within the combustion chamber including at least an approximately end period of the one combustion stroke on the basis of the measured combustion state related parameter;
d) predictive combustion time duration determining means for determining a target recirculation rate to be normally achieved by controlling an opening angle of the exhaust gas recirculation control valve means via the EGR control signal on the basis of the detected engine driving condition and for determining a length of a predictive combustion time duration on the basis of the determined target exhaust gas recirculation rate; and
e) failure diagnosing means for comparing the length of the measured combustion time duration with that of the predictive combustion time duration so as to diagnose whether a failure occurs in the exhaust gas recirculation system according to a result of the comparison.
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Accused Products
Abstract
In apparatus and method for diagnosing an EGR (Exhaust Gas Recirculation) system in an internal combustion engine, a combustion time duration (MT) in one combustion stroke is measured, the combustion time duration including at least an approximately combustion end period, a predictive (reference) combustion time duration (MTA) in one combustion stroke is derived on the basis of engine driving condition and a target EGR rate to be carried out by the EGR system, and the measured combustion time duration (MT) is compared with the predictive (reference) combustion time duration (MTA). Depending on a result of the comparison, the diagnosing apparatus and method determine whether a failure in the EGR system occurs.
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Citations
11 Claims
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1. An apparatus for diagnosing an exhaust gas recirculation system having exhaust gas recirculation control valve means interposed in an exhaust gas recirculation passage of an internal combustion engine so as to recirculate part of exhaust gas into a suction system of the engine in response to an EGR control signal, comprising:
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a) detecting means for detecting an engine driving condition; b) combustion state related parameter measuring means for measuring a combustion state related parameter of at least one combustion chamber of engine cylinders; c) combustion time duration measuring means for measuring a length of a combustion time duration in one combustion stroke within the combustion chamber including at least an approximately end period of the one combustion stroke on the basis of the measured combustion state related parameter; d) predictive combustion time duration determining means for determining a target recirculation rate to be normally achieved by controlling an opening angle of the exhaust gas recirculation control valve means via the EGR control signal on the basis of the detected engine driving condition and for determining a length of a predictive combustion time duration on the basis of the determined target exhaust gas recirculation rate; and e) failure diagnosing means for comparing the length of the measured combustion time duration with that of the predictive combustion time duration so as to diagnose whether a failure occurs in the exhaust gas recirculation system according to a result of the comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for diagnosing an exhaust gas recirculation system having exhaust gas recirculation control valve means interposed in an exhaust gas recirculation passage of an internal combustion engine so as to recirculate part of exhaust gas into a suction system of the engine in response to an EGR control signal, said apparatus comprising:
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a) first measuring means for measuring an engine driving condition; b ) first detecting means for detecting an ignition timing of a corresponding one of combustion chambers in engine cylinders; b) second measuring means for measuring a magnitude of the inner cylinder pressure (Pi) in the corresponding one of the engine combustion chambers from a time when the first detecting means detects the ignition timing; c) time duration measuring means for measuring a predetermined time duration from a start time at which the inner cylinder pressure indicates a first predetermined value (MPi) when the ignition timing is detected to an end time at which the inner combustion chamber pressure again indicates the first predetermined value (MPi); d) reference time duration calculating means for driving a targets exhaust gas recirculation rate on the basis of the detected engine driving condition and for calculating a reference time duration (MT1, MT2) on the basis of the calculated target gas recirculation rate; e) comparing means for comparing the predetermined time duration (MT) and the reference time duration (MTA) and for diagnosing whether a failure occurs in the exhaust gas recirculation system according to a result of the comparison; and f) outputting means for outputting a warning signal when said comparing means diagnoses that the failure occurs in the exhaust gas recirculation system.
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11. A method fior diagnosing an exhaust gas recirculation system having exhaust gas recirculation control valve means interposed in an exhaust gas recirculation passage of an internal combustion engine so as to recirculate part of exhaust gas into a suction system of the engine in response to an EGR control signal, comprising the steps of:
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a) detecting an engine driving condition; b) measuring a combustion state related parameter of at least one combustion chamber of engine cylinders; c) measuring a length of a combustion time duration in one combustion stroke within the combustion chamber including at least an approximately end period of the one combustion stroke on the basis of the measured combustion state related parameter; d) determining a target recirculation rate to be normally achieved by controlling an opening angle of the exhaust gas recirculation control valve means via the EGR control signal on the basis of the detected engine driving condition and determining a length of a predictive combustion time duration on the basis of the determined target exhaust gas recirculation rate; e) comparing the length of the measured combustion time duration with that of the predictive combustion time duration so as to diagnose whether a failure occurs in the exhaust gas recirculation system according to a result of the comparison; and f) outputting a warning signal if diagnosing that the failure occurs in the exhaust gas recirculation system at the step e).
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Specification