Temperature gradient correction of ammonia storage model

摘要

An exhaust gas treatment system includes a SCR device that stores a reductant that reacts with the NOx emissions and a reductant supply system to inject the reductant according to a reductant load model. At least one temperature sensor or model generates a temperature signal indicating an SCR temperature of the SCR device. The exhaust gas treatment system further includes a control module in electrical communication with the reductant supply system. The control module is configured to determine an amount of reductant that slips from the SCR device based on the at least one temperature signal and the rate of change of the SCR temperature. The control module further determines a correction factor based on the amount of slipped reductant to modify the reductant load model.

主权项

1. An exhaust gas treatment system for use with an internal combustion engine to treat exhaust gas containing NOx emissions, the exhaust gas treatment system comprising:
a selective catalytic reductant (SCR) device that stores a reductant that reacts with the NOx emissions; a reductant supply system configured to inject the reductant according to a reductant load model; and an electronic control module including a non-transitory memory having computer readable instructions stored thereon, and a computer processor configured to execute the computer readable instructions that perform operations of: generating at least one temperature signal indicating an SCR temperature of the SCR device; determining an actual amount of reductant that slips from the SCR device based on the at least one temperature signal and a rate of change of the SCR temperature; determining a correction factor based on the actual amount of slipped reductant to modify the reductant load model, the correction factor based on a difference between the actual amount of slipped reductant and an amount of reductant stored on the SCR device, the amount of reductant stored on the SCR device is based on the reductant load model stored in the non-transitory memory, an age of the SCR device, and the correction factor; calculating the age of SCR device based on a temperature realized by the SCR device over a time period to determine an age factor; updating the load model based on the age factor to the determine the amount of reductant stored on the SCR device; determining a desired load of the SCR device based on at least one driving condition; and adjusting the reductant injected by the reductant supply system based on the updated load model and the correction factor to achieve the desired load.