Feedback control in selective catalytic reduction
First Claim
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1. An apparatus for generating a dosing command for introducing a reductant into an exhaust system comprising:
- at least one sensor configured to detect NOx produced during engine combustion; and
a controller operatively connected with the at least one sensor, the controller configured to receive an output of the at least one sensor based on the NOx detected by the at least one sensor, the controller configured to process the output from the at least one sensor and generate a resulting dosing command having an instruction to introduce a reductant into the exhaust system, the resulting dosing command including a lower limit dosing command, an upper limit dosing command, and a weighing factor, the weighing factor configured to be applied to the lower and upper limit dosing commands in a calculation to provide the resulting dosing command, such that the resulting dosing command is a value within end values of the lower and upper limit dosing commands.
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Abstract
An apparatus for introducing a reductant into an exhaust system is described. The apparatus includes a controller that generates a resulting dosing command used as an instruction to release an amount of reductant into the exhaust system. The controller includes a feedback control module that generates a weighing factor. The weighing factor is configured to be applied to a lower limit dosing command and configured to be applied to an upper limit dosing command, where the lower and upper limit dosing commands converted by the weighing factor are used by the controller to generate the resulting dosing command.
12 Citations
24 Claims
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1. An apparatus for generating a dosing command for introducing a reductant into an exhaust system comprising:
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at least one sensor configured to detect NOx produced during engine combustion; and a controller operatively connected with the at least one sensor, the controller configured to receive an output of the at least one sensor based on the NOx detected by the at least one sensor, the controller configured to process the output from the at least one sensor and generate a resulting dosing command having an instruction to introduce a reductant into the exhaust system, the resulting dosing command including a lower limit dosing command, an upper limit dosing command, and a weighing factor, the weighing factor configured to be applied to the lower and upper limit dosing commands in a calculation to provide the resulting dosing command, such that the resulting dosing command is a value within end values of the lower and upper limit dosing commands. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 24)
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14. A method of generating a dosing command to introduce a reductant into an exhaust system comprising:
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detecting NOx produced during engine combustion with a sensor; receiving an output of the NOx detected by the sensor with a controller; processing the output with the controller to generate a dosing command that comprises; calculating a lower limit dosing command with the controller, the lower limit dosing command comprising a calculation based on a maximum allowed NOx emission for the exhaust system; calculating an upper limit dosing command with the controller, the upper limit dosing command comprising a calculation based on a maximum allowed ammonia slip; generating a weighing factor with the controller, the weighing factor comprising a calculation based on a detected NOx output; processing the lower limit and upper limit dosing commands with the controller using the weighing factor; and generating a resulting dosing command with the controller based on a calculation of the processed lower limit and upper limit dosing commands, the resulting dosing command being a value within end values of the lower and upper limit dosing commands. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A selective catalyst reduction exhaust system comprising:
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a selective catalyst reduction device including an inlet and an outlet; at least one sensor operatively connected to the outlet of the selective catalyst reduction device, the at least one sensor configured to detect NOx produced during engine combustion; a controller operatively connected with the at least one sensor, the controller configured to receive an output of the at least one sensor based on the NOx detected by the at least one sensor, the controller configured to process the output from the at least one sensor and generate a resulting dosing command having an instruction to introduce a reductant into the exhaust system, the resulting dosing command including a lower limit dosing command, an upper limit dosing command, and a weighing factor, the weighing factor configured to be applied to the lower and upper limit dosing commands, the weighing factor configured to convert the lower and upper limit dosing commands to end values of the resulting dosing command; and a doser operatively connected to the controller and connected to the selective catalyst reduction device, the doser configured to receive the resulting dosing command and configured to introduce the reductant into the exhaust system at the inlet of the selective catalyst reduction device and based on the resulting dosing command.
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Specification