Exhaust leak detection
First Claim
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1. A method for detecting an exhaust leak in an engine control system having an exhaust gas oxygen sensor upstream of a catalyst and an exhaust gas oxygen sensor downstream of the catalyst and an electronic engine control system for operating an internal combustion engine, including the steps of:
- monitoring the output voltage signals from the exhaust gas oxygen sensor downstream of the catalyst;
computing the average output voltages from the exhaust gas oxygen sensor downstream of the catalyst;
comparing the computed average with respect to a calibrated constant;
if the average is smaller than the constant, setting a code indicating an exhaust leak; and
monitoring the output voltage signals from the exhaust gas oxygen sensor upstream of the catalyst determining a leak condition if the upstream exhaust gas oxygen sensor switches rapidly at idle and low engine speeds.
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Abstract
A method of operating an engine detects an exhaust leak from the engine exhaust of an internal combustion engine using engine operating parameters. Signals from an exhaust gas oxygen sensor downstream of a catalyst indicates a leak if the signals are smaller than a predetermined constant.
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Citations
4 Claims
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1. A method for detecting an exhaust leak in an engine control system having an exhaust gas oxygen sensor upstream of a catalyst and an exhaust gas oxygen sensor downstream of the catalyst and an electronic engine control system for operating an internal combustion engine, including the steps of:
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monitoring the output voltage signals from the exhaust gas oxygen sensor downstream of the catalyst; computing the average output voltages from the exhaust gas oxygen sensor downstream of the catalyst; comparing the computed average with respect to a calibrated constant; if the average is smaller than the constant, setting a code indicating an exhaust leak; and monitoring the output voltage signals from the exhaust gas oxygen sensor upstream of the catalyst determining a leak condition if the upstream exhaust gas oxygen sensor switches rapidly at idle and low engine speeds.
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2. An apparatus for detecting an exhaust leak including:
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an internal combustion engine having an input for receiving an air/fuel mixture and an output for passing exhaust gas; a catalyst coupled to said engine output for processing exhaust gas passed by the engine and having an output for passing the processed exhaust gas; a downstream exhaust gas oxygen sensor coupled to the output of said catalyst; an electronic engine control module coupled to receive an input from said downstream exhaust gas oxygen sensor and having an output for controlling the air/fuel input to said engine input and including means for monitoring the voltage output signal of the exhaust gas oxygen sensor downstream of said catalyst, computing the average output voltages from the exhaust gas oxygen sensor downstream of the catalyst, comparing the computed average with respect to a calibrated constant, and, if the average is smaller than the constant, setting a code indicating an exhaust leak. - View Dependent Claims (3, 4)
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Specification