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CN-115596537-B - Multi-layer exhaust gas burner control for SCR catalyst warm-up

CN115596537BCN 115596537 BCN115596537 BCN 115596537BCN-115596537-B

Abstract

An exhaust gas control system for a vehicle includes a temperature sensor positioned in the exhaust system downstream of an exhaust gas burner and upstream of an SCR catalyst. The temperature sensor is configured to generate a measurement signal indicative of a temperature of exhaust flowing through the exhaust system at an outlet of a DPF positioned downstream of the exhaust burner. The exhaust control module is configured to turn on the exhaust burner to heat the exhaust gas, monitor a temperature of the exhaust gas based on the measurement signal, turn off the exhaust burner based on an upper threshold temperature of the exhaust gas subsequent to turning on the exhaust burner, and turn on the exhaust burner based on a lower threshold temperature of the exhaust gas subsequent to turning off the exhaust burner. The lower threshold temperature is less than the upper threshold temperature.

Inventors

  • THOMAS M. HARRIS
  • James E. McCarthy Jr.

Assignees

  • 天纳克汽车经营有限公司

Dates

Publication Date
20260505
Application Date
20220705
Priority Date
20220524

Claims (11)

  1. 1. An exhaust gas control system for a vehicle, the exhaust gas control system comprising: A temperature sensor positioned downstream of an exhaust gas burner and upstream of a selective catalytic reduction catalyst in an exhaust system of the vehicle, wherein the temperature sensor is configured to generate a measurement signal indicative of a temperature of exhaust gas flowing through the exhaust system at an outlet of a diesel particulate filter positioned downstream of the exhaust gas burner, and An exhaust control module configured to: detecting a cold start condition, and in response to detecting the cold start condition, turning on the exhaust gas burner to heat the exhaust gas, wherein turning on the exhaust gas burner comprises combusting air and fuel in a combustion chamber of the exhaust gas burner, Monitoring the temperature of the exhaust gas based on the measurement signal, Subsequently to turning on the exhaust gas burner, turning off the exhaust gas burner based on the temperature of the exhaust gas reaching a first upper threshold temperature, and Continuing to monitor the decreasing exhaust gas temperature subsequent to closing the exhaust gas burner and opening the exhaust gas burner based on the temperature of the exhaust gas reaching a first lower threshold temperature, wherein the first lower threshold temperature is less than the first upper threshold temperature; The exhaust control module is further configured to detect a sustained low load condition after the cold start condition and operate the exhaust burner based on a second upper threshold temperature and a second lower threshold temperature in response to detecting the sustained low load condition, the second upper threshold temperature being less than the first upper threshold temperature.
  2. 2. The exhaust gas control system of claim 1, wherein the temperature sensor is positioned at an outlet of the diesel particulate filter.
  3. 3. The exhaust control system of claim 1, wherein the exhaust control module is configured to turn on the exhaust burner prior to engine start-up.
  4. 4. The exhaust gas control system of claim 1, wherein the exhaust gas control module is configured to maintain the exhaust gas at the first lower threshold temperature.
  5. 5. The exhaust gas control system of claim 1, wherein, subsequent to turning on the exhaust gas burner based on the temperature of the exhaust gas reaching the first lower threshold temperature, the exhaust gas control module is configured to turn off the exhaust gas burner based on the temperature of the exhaust gas reaching the first upper threshold temperature.
  6. 6. The exhaust gas control system of claim 1, wherein the first upper threshold temperature is greater than or equal to 300 ℃.
  7. 7. The exhaust control system of claim 1, wherein the exhaust control module is configured to detect a cold start condition and to turn on the exhaust burner prior to engine start in response to detecting the cold start condition.
  8. 8. The exhaust control system of claim 1, wherein the exhaust control module is configured to increase engine idle speed when the exhaust burner is turned on.
  9. 9. The exhaust control system of claim 1, wherein the exhaust control module is configured to detect a cold start condition, operate the exhaust burner based on a first set of thresholds including the first upper threshold temperature and the first lower threshold temperature in response to detecting the cold start condition, and operate the exhaust burner based on a second set of thresholds including the second upper threshold temperature and the second lower threshold temperature in response to not detecting the cold start condition.
  10. 10. The exhaust gas control system of claim 1, further comprising: An air pump configured to pump air into a combustion chamber of the exhaust gas combustor; A spark plug configured to ignite an air/fuel mixture within a combustion chamber of the exhaust gas combustor; A fuel control module configured to selectively actuate fuel injectors and initiate fuel injection prior to engine start-up when an engine of the vehicle is shut-down; A pump control module configured to selectively turn on the air pump prior to the engine starting when the engine is off, and A spark control module configured to selectively apply power to the spark plug and begin providing spark when the engine is off and before the engine is started.
  11. 11. The exhaust gas control system of claim 1, further comprising: A diesel emission fluid injector configured to inject a diesel emission fluid into the exhaust system upstream of the selective catalytic reduction catalyst, and A diesel emission fluid control module configured to selectively actuate the diesel emission fluid injector and initiate injection of diesel emission fluid prior to engine start-up when an engine of the vehicle is shut down.

Description

Multi-layer exhaust gas burner control for SCR catalyst warm-up Cross Reference to Related Applications The present application claims the benefit of U.S. provisional application No. 63/220,100 filed on 7.9 of 2021. The entire disclosure of the above-referenced application is incorporated herein by reference. Technical Field The present disclosure relates to exhaust gas control systems and methods, and more particularly to systems and methods for controlling a selective reduction catalyst (SCR) temperature and airflow into an exhaust system. Background The information provided in this section is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Air is drawn into the engine through an intake manifold. The air is mixed with fuel from one or more fuel injectors to form an air/fuel mixture. The air/fuel mixture is combusted within one or more cylinders of the engine. Combustion of the air/fuel mixture produces torque. Exhaust gas produced by combustion of the air/fuel mixture is expelled from the cylinders into an exhaust system. Exhaust from an engine burning diesel fuel with excess air may contain Particulate Matter (PM) and gases. The exhaust gas contains nitrogen oxides (NOx), such as Nitric Oxide (NO) and nitrogen dioxide (NO 2). The exhaust treatment system may be used to reduce the amount of NOx and PM in the exhaust. The exhaust treatment system may include a Diesel Oxidation Catalyst (DOC). The DOC removes hydrocarbons and/or oxides of carbon from the exhaust. The exhaust treatment system may also include a Diesel Particulate Filter (DPF) that removes Particulate Matter (PM) from the exhaust. The exhaust treatment system may also include a Selective Catalytic Reduction (SCR) catalyst. Diesel Exhaust Fluid (DEF) injectors inject DEF (e.g., aqueous urea) into a decomposition tube or reactor located upstream of an SCR catalyst. When DEF encounters hot exhaust gases in the decomposition tube, the water partially evaporates and the urea decomposes to form ammonia. Ammonia (NH 3) provided by the DEF is absorbed by the SCR catalyst. When ammonia is present on the surface of the SCR catalyst and the catalyst is hot, NOx in the exhaust gas will react with the ammonia to form nitrogen (N 2). In this way, the amount of NOx emitted by the engine is reduced. Disclosure of Invention An exhaust gas control system for a vehicle includes a temperature sensor positioned in an exhaust system of the vehicle downstream of an exhaust gas burner and upstream of a Selective Catalytic Reduction (SCR) catalyst. The temperature sensor is configured to generate a measurement signal indicative of a temperature of exhaust gas flowing through the exhaust system at an outlet of a Diesel Particulate Filter (DPF) positioned downstream of the exhaust burner. The exhaust control module is configured to turn on the exhaust gas burner to heat the exhaust gas by combusting air and fuel in a combustion chamber of the exhaust gas burner, monitor a temperature of the exhaust gas based on the measurement signal, turn off the exhaust gas burner based on an upper threshold temperature of the exhaust gas subsequent to turning on the exhaust gas burner, and turn on the exhaust gas burner based on a lower threshold temperature of the exhaust gas subsequent to turning off the exhaust gas burner. The lower threshold temperature is less than the upper threshold temperature. In other features, the temperature sensor is positioned at an outlet of the DPF. The exhaust control module is configured to turn on the exhaust burner prior to engine start-up. The exhaust control module is configured to maintain the exhaust at the lower threshold temperature. The exhaust control module is configured to shut down the exhaust burner based on the upper threshold temperature subsequent to turning on the exhaust burner based on the lower threshold temperature. The upper threshold temperature is greater than or equal to 300 ℃. The exhaust control module is configured to detect a cold start condition and to turn on the exhaust burner prior to engine start in response to detecting the cold start condition. The exhaust control module is configured to increase an engine idle speed when the exhaust burner is turned on. In other features, the exhaust control module is configured to detect a cold start condition, operate the exhaust burner based on a first set of thresholds including the upper threshold temperature and the lower threshold temperature in response to detecting the cold start condition, and operate the exhaust burner based on a second set of thresholds including a second upper threshold temperature and a second lower threshold temperature in response to not detecting