Pressure sensor diagnosis via a computer
First Claim
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1. A system for a vehicle having an engine with an exhaust system, the system comprising:
- a pressure sensor coupled in the engine exhaust;
a particulate filter coupled in the engine exhaust; and
a computer storage medium having a computer program encoded therein for determining degradation of said exhaust pressure sensor, comprising;
code for determining at least a parameter based on at least two flow conditions;
code for measuring a signal from the exhaust pressure sensor; and
code for determining degradation of the exhaust pressure sensor based at least on said parameter and said signal.
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Abstract
A method is described for controlling regeneration of a particulate filter based on at least a sensor, such as a differential pressure sensor. Degradation of the sensor is then detected in a variety of ways. One approach takes advantage of the slowly varying flow resistance of the filter compared with the more rapid variations in flow caused by changing engine conditions. Default operation is then taken when a degraded sensor is detected.
85 Citations
26 Claims
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1. A system for a vehicle having an engine with an exhaust system, the system comprising:
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a pressure sensor coupled in the engine exhaust;
a particulate filter coupled in the engine exhaust; and
a computer storage medium having a computer program encoded therein for determining degradation of said exhaust pressure sensor, comprising;
code for determining at least a parameter based on at least two flow conditions;
code for measuring a signal from the exhaust pressure sensor; and
code for determining degradation of the exhaust pressure sensor based at least on said parameter and said signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for monitoring a pressure sensor, the sensor responding to both an amount of exhaust gas flow and accumulation of sort in a particulate filer, the method comprising:
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measuring a signal from the pressure sensor at least during two substantially different flow conditions where variation of the amount of exhaust gas flow between said two conditions is greater than a first amount while accumulation of soot is less than a second amount; and
determining degradation of the sensor based on said signal and a reference. - View Dependent Claims (8, 9, 10, 11, 14)
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12. A method for monitoring a pressure sensor in an engine exhaust, the method comprising:
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measuring a signal from the pressure sensor during at least a first and second flow condition wherein said first and second flow condition include a high floe and a low flow condition said measuring occurring while soot buildup is less than a selected amount;
determining an expected response of the sensor during said flow conditions; and
determining degradation of the sensor when said signal differs by an amount from said expected response. - View Dependent Claims (13, 15, 16, 20)
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17. A system for a vehicle having an engine with an exhaust system, the system comprising:
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a pressure sensor coupled in the engine exhaust;
a particulate filter coupled in the engine exhaust; and
a computer storage medium having a computer program encoded therein for determining degradation of said exhaust pressure sensor, comprising;
code for determining an expected sensor response;
code for measuring a signal response from the exhaust pressure sensor during at least a selected engine operating condition; and
code for determining degradation of the exhaust pressure sensor based at least on said expected sensor response and said signal response. - View Dependent Claims (18, 19)
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21. A system for a vehicle having an engine with an exhaust system, the system comprising:
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a particulate filter coupled in the engine exhaust;
a sensor coupled in the engine exhaust; and
a computer storage medium having a computer program encoded therein, comprising;
code for regenerating said particulate filter based on said sensor; and
code for determining degradation of said sensor based on an operating parameter. - View Dependent Claims (22, 23)
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24. A system for a vehicle having an engine with an exhaust system, the system comprising:
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a sensor coupled in the engine exhaust so that the sensor is exposed to the exhaust;
a particulate filter coupled in the engine exhaust with the sensor; and
a computer storage medium having a computer program encoded therein for determining degradation of said sensor, comprising;
code for determining at least an operating parameter of the sensor based on at least two flow conditions of the exhaust;
code for measuring a signal from the sensor over time; and
code for determining degradation of the sensor over time based at least on said parameter and said signal. - View Dependent Claims (25, 26)
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Specification