Method and system for optimizing purge of exhaust gas constituent stored in an emission control device
First Claim
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1. A system for optimizing a purge time for an emission control device located in the exhaust passage of an engine, during which an amount of a previously-stored constituent gas of the engine-generated exhaust gas is released from the device, the system comprising:
- an oxygen sensor providing an output signal representative of the concentration of oxygen present in the exhaust flowing through the device during a sampling period; and
a control module for detecting the peak voltage of the sensor output voltage, calculating a purge time correction factor related to the peak voltage, and calculating a subsequent purge time as a function of the product of the correction factor and a present purge time.
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Abstract
A method and system for optimizing the purging of a constituent gas of a vehicle engine'"'"'s generated exhaust gas from an emission control device is disclosed wherein the amplitude of the output signal generated by a downstream switching oxygen sensor, and the time response of the sensor, is used to iteratively adjust a current purge time to obtain an optimized purge time.
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Citations
20 Claims
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1. A system for optimizing a purge time for an emission control device located in the exhaust passage of an engine, during which an amount of a previously-stored constituent gas of the engine-generated exhaust gas is released from the device, the system comprising:
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an oxygen sensor providing an output signal representative of the concentration of oxygen present in the exhaust flowing through the device during a sampling period; and
a control module for detecting the peak voltage of the sensor output voltage, calculating a purge time correction factor related to the peak voltage, and calculating a subsequent purge time as a function of the product of the correction factor and a present purge time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A closed-loop method of optimizing a purge time for an emission control device located in the exhaust passage of an engine upstream from a switching oxygen sensor, during which an amount of a previously-stored constituent gas of the engine-generated exhaust gas is released from the device, the method comprising:
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detecting the voltage of the sensor for an existing purge time, following an existing fill time, to determine whether the purge time should be changed;
if the peak voltage of the sensor is less than a predetermined reference voltage then calculating a first saturation time based on the peak voltage;
if the peak voltage is greater than the reference voltage then measuring the time that the peak voltage remains above the reference voltage and calculating a second saturation time related to the time that the peak voltage remains above the reference voltage;
utilizing the error between a desired saturation time and the calculated saturation time as feedback to a controller for producing a purge time correction factor;
calculating the next purge time equal to the product of the correction factor and the previous purge time and;
storing the purge time when the difference between a present and subsequent purge time is greater than a predetermined tolerance. - View Dependent Claims (9)
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10. A method of optimizing a purge time for an emission control device located in the exhaust passage of an engine upstream from an oxygen sensor, during which an amount of a previously-stored constituent gas of the engine-generated exhaust gas is released from the device, the method comprising:
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detecting the sensor output voltage;
calculating a purge time correction factor related to a characteristic of the sensor output voltage; and
calculating a subsequent purge time as a function of the product of the correction factor and a present purge time. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification