Exhaust aftertreatment system diagnostic and conditioning
An engine diagnostic tool includes a diagnostic engine calibration module structured to include a plurality of diagnostic processes for operating an internal combustion engine system of an immobilized vehicle. One or more of the plurality of diagnostic processes are structured to be an intrusive diagnostic process for the internal combustion engine system, wherein the intrusive diagnostic process causes the internal combustion engine system to operate outside of one or more calibration parameters. The diagnostic engine module is further structured to control the order and timing of each diagnostic process in the plurality of diagnostic processes.
1. A method for diagnosing and conditioning a system of a vehicle, comprising:
immobilizing the vehicle in a controlled environment;
removing a production engine calibration program from an electronic control unit of the internal combustion engine system;
uploading a diagnostic engine calibration program to the electronic control unit;
running the diagnostic engine calibration program while the vehicle is immobilized in the controlled environment without user intervention, the diagnostic engine calibration including a plurality of diagnostic processes for operating an immobilized vehicle, wherein the plurality of diagnostic processes includes a high NOx sensor rationality test that includes disabling a DEF dosing event, providing an amount of engine out NOx at or above a predefined high NOx concentration threshold, operating an engine at or above a high speed threshold, determining a NOx concentration across a SCR system, and comparing the determined NOx concentration against a predetermined fault threshold to diagnose a NOx sensor;
removing the diagnostic engine calibration program from the electronic control unit after completion of the plurality of diagnostic processes; and
uploading the production engine calibration program to the electronic control unit;
wherein one or more of the plurality of diagnostic processes cause the internal combustion engine system to operate outside of one or more calibration parameters.
2. The method of claim 1 , further comprising controlling the order and timing of each diagnostic process in the plurality of diagnostic processes.
3. The method of claim 1 , wherein the diagnostic processes include a SCR performance test before an SCR regeneration event, wherein the SCR performance test before an SCR regeneration event includes substantially maximizing an exhaust gas flow rate, and monitoring a NOx conversion efficiency at various DEF dosing rates.
4. The method of claim 1 , wherein the diagnostic processes include a SCR performance test with an SCR regeneration event, wherein the SCR performance test with an SCR regeneration event includes elevating an exhaust gas temperature and reducing an engine speed for a predetermined amount of time followed by substantially maximizing an exhaust gas flow rate, and monitoring a NOx conversion efficiency at various DEF dosing rates.
5. The method of claim 1 , wherein the plurality of diagnostic processes includes a low NOx sensor rationality test, wherein the low NOx sensor rationality test includes disabling a DEF dosing event, providing about 75 ppm to 100 ppm NOx out of the engine, and determining a NOx concentration across the SCR system, wherein the determined NOx concentration is compared against a predetermined fault threshold.
6. The method of claim 1 , wherein the plurality of diagnostic processes includes a DOC and DPF temperature sensor rationality test, wherein the DOC and DPF temperature sensor rationality test includes comparing DOC and DPF temperature sensor readings to each other after an engine has run at an idle speed for a predetermined amount of time after running the engine at a relatively higher speed for another predetermined amount of time.
7. The method of claim 1 , wherein the plurality of diagnostic processes includes a SCR temperature sensor rationality test, wherein the SCR temperature sensor rationality test includes comparing SCR temperature sensor readings to each other after an engine has run at an idle speed for a predetermined amount of time after running the engine at a relatively higher speed for another predetermined amount of time.