NOx sensor plausibility monitor
First Claim
1. A vehicle comprising:
- an internal combustion engine; and
an exhaust system in fluid communication with the engine, and including;
a selective catalytic reduction (SCR) device;
a rear NOx sensor positioned downstream of the SCR device, and configured to measure NOx levels downstream of the SCR device; and
a controller in communication with the rear NOx sensor, wherein the controller includes a processor and tangible, non-transitory memory on which is recorded;
a plurality of data maps each indexed by a different pair of exhaust system performance values and each having a plurality of cells, wherein the cells of each data map are populated by estimated downstream NOx levels; and
a plurality of binary maps each indexed by a corresponding one of the pairs of exhaust system performance values and having a plurality of cells, wherein each of the cells of each of the binary maps is populated by a binary value of 1 or 0;
wherein the processor is configured to;
extract information from the data maps and binary values from the binary maps, receive measurements of the downstream NOx levels from the rear NOx sensor, verify the plausibility of the received measurements of the downstream NOx levels using the extracted binary values from the binary maps and the extracted information from the data maps, and execute a control action with respect to the exhaust system using the downstream NOx level measurements from the rear NOx sensor and the extracted information from the data maps, including diagnosing performance of the rear NOx sensor within the exhaust system.
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Accused Products
Abstract
A vehicle includes an engine, an exhaust system, and a controller. The exhaust system includes a selective catalytic reduction (SCR) device, and a rear nitrogen oxide (NOx) sensor. The controller, which is in communication with the NOx sensor, includes a processor and tangible, non-transitory memory. A plurality of data maps and a plurality of binary maps are recorded in memory. Each data map is indexed by a different pair of exhaust system performance values. Each cell of each data map is populated by estimated downstream NOx levels. The binary maps are indexed by one of the pairs of exhaust system performance values. Each cell of each binary map is populated by a binary value, i.e., a 0 or 1. The controller uses the data maps and the binary maps to execute a control action with respect to the exhaust system, such as verifying plausibility of the rear NOx sensor.
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Citations
18 Claims
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1. A vehicle comprising:
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an internal combustion engine; and an exhaust system in fluid communication with the engine, and including; a selective catalytic reduction (SCR) device; a rear NOx sensor positioned downstream of the SCR device, and configured to measure NOx levels downstream of the SCR device; and a controller in communication with the rear NOx sensor, wherein the controller includes a processor and tangible, non-transitory memory on which is recorded; a plurality of data maps each indexed by a different pair of exhaust system performance values and each having a plurality of cells, wherein the cells of each data map are populated by estimated downstream NOx levels; and a plurality of binary maps each indexed by a corresponding one of the pairs of exhaust system performance values and having a plurality of cells, wherein each of the cells of each of the binary maps is populated by a binary value of 1 or 0; wherein the processor is configured to;
extract information from the data maps and binary values from the binary maps, receive measurements of the downstream NOx levels from the rear NOx sensor, verify the plausibility of the received measurements of the downstream NOx levels using the extracted binary values from the binary maps and the extracted information from the data maps, and execute a control action with respect to the exhaust system using the downstream NOx level measurements from the rear NOx sensor and the extracted information from the data maps, including diagnosing performance of the rear NOx sensor within the exhaust system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for use in a vehicle having a controller, an internal combustion engine, and an exhaust system having a selective catalytic reduction (SCR) device and a rear NOx sensor positioned downstream of the SCR device, the method comprising:
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recording a plurality of data maps in memory of the controller, wherein each of the data maps is indexed by a different pair of exhaust system performance values, and wherein cells of each of the data map are populated by estimated downstream NOx levels; recording a plurality of binary maps each having at least nine cells in the memory of the controller, wherein each of the binary maps is indexed by a corresponding one of the pairs of exhaust system performance values, and wherein each of the at least nine cells is populated by a 1 or a 0; receiving, via the controller, the exhaust system performance values, including downstream NOx level measurements from the rear NOx sensor; extracting information from the data maps and the binary maps; and verifying, via the controller, the plausibility of the downstream NOx level measurements from the rear NOx sensor using the extracted information, including; comparing, via the controller, the downstream NOx level measurements to calibrated thresholds for a plurality of different vehicle throttle events to thereby verify the plausibility of the downstream NOx level measurements; and executing a control action with respect to the exhaust system using the NOx level measurements from the rear NOx sensor and the extracted information from the data maps, including diagnosing performance of the rear NOx sensor within the exhaust system. - View Dependent Claims (10, 11, 12, 13)
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14. A controller for a vehicle having an engine and an exhaust system that includes a rear nitrogen oxide (NOx) sensor, the controller comprising:
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a host machine having a processor that is in communication with the rear nitrogen oxide (NOx) sensor, wherein the rear NOx sensor is positioned downstream of a selective catalytic reduction (SCR) device and transmits measured downstream NOx levels to the processor; and tangible, non-transitory memory on which is recorded; process instructions that are executable by the processor; a plurality of data maps each indexed by a different pair of exhaust system performance values, and each having a plurality of cells, wherein the cells of each data map are populated by estimated downstream NOx levels; and a plurality of binary maps each indexed by a corresponding one of the pairs of exhaust system performance values, and each having a plurality of cells, wherein each cell of each binary map is populated by a binary value of 1 or 0; wherein the processor is configured to selectively execute the process instructions such that the host machine extracts information from the data maps and from the binary maps, and thereafter verifies the plausibility of the measured downstream NOx levels from the rear NOx sensor using the extracted information, and to execute a control action with respect to the exhaust system using the NOx level measurements from the rear NOx sensor and the extracted information from the data maps, including identifying ideal entry conditions for diagnosing performance of the rear NOx sensor within the exhaust system. - View Dependent Claims (15, 16, 17, 18)
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Specification