System for controlling the urea supply to SCR catalysts
First Claim
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1. A reductant dosing control system, for use in an SCR system of a motor vehicle, comprising:
- an input receiving a NOx feedback signal from an NOx sensor provided to said SCR system;
a base dosing module calculating a quantity of required reductant to inject in front of a SCR catalyst of said SCR system based on the NOx feedback signal, wherein the SCR catalyst has ammonia storage properties; and
an output signaling a reductant metering mechanism to periodically inject excess reductant based on the required quantity of reductant.
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Abstract
A reductant dosing control system, for use in a Selective Catalytic Reduction (SCR) system of a motor vehicle includes an input receiving a NOx feedback signal from an NOx sensor provided to the SCR system. A base dosing module calculates a required quantity of reductant to inject in front of a SCR catalyst of the SCR system based on the NOx feedback signal. The SCR catalyst has ammonia storage properties. An output signals a reductant metering mechanism to periodically or continuously inject excess reductant based on the required quantity of reductant.
80 Citations
20 Claims
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1. A reductant dosing control system, for use in an SCR system of a motor vehicle, comprising:
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an input receiving a NOx feedback signal from an NOx sensor provided to said SCR system;
a base dosing module calculating a quantity of required reductant to inject in front of a SCR catalyst of said SCR system based on the NOx feedback signal, wherein the SCR catalyst has ammonia storage properties; and
an output signaling a reductant metering mechanism to periodically inject excess reductant based on the required quantity of reductant. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A reductant dosing control method, for use in an SCR system of a motor vehicle, comprising:
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receiving a NOx feedback signal from an NOx sensor provided to said SCR system;
calculating a required quantity of reductant to inject in front of a SCR catalyst of said SCR system based on the NOx feedback signal, wherein the SCR catalyst has ammonia storage properties; and
periodically supplying an excess amount of reductant based on the required quantity of reductant. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A selective catalytic reduction system for use in a motor vehicle, comprising:
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a Zeolite based catalyst resident in an exhaust system receptive of NOx exhaust exiting a diesel engine;
a supply of reductant;
a reductant dosing mechanism adapted to inject reductant into the exhaust system before the catalyst according to a variable reductant dosing setpoint;
an NOx feedback sensor supplying a NOx feedback signal indicating an amount of NOx exhaust exiting the diesel engine; and
a reductant dosing control system adapted to calculate a required quantity of reductant to inject in front of the Zeolite based SCR catalyst based on the NOx feedback signal, to modify the quantity of reductant based on sensory signals from engine mass airflow sensors of said diesel engine and temperature sensors of the enclosure, and to communicate a reductant set point to said reductant dosing mechanism based on the required quantity of reductant. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification