APPARATUS, SYSTEM AND METHOD FOR MITIGATING DIESEL EXHAUST FLUID DEPOSITS AND ASSOCIATED CONDITIONS
FIG2 is a block diagram of a controller of the engine system of FIG1 according to one embodiment of the invention
More specifically, as shown in the illustrated embodiment of FIG2, the controller 300 includes a diagnostic fault module 310, fault mitigation module 320, diagnostic interrupt module 330, and decomposition tube regeneration module 340. The controller 300 also receives an SCR inlet NOx signal 350 from the NOx sensor 160, an SCR outlet NOx signal 355 from the NOx sensor 162, a DPF outlet pressure signal 360 from the pressure sensor 164, and other diagnostic signals from any of various other sensors. The controller 300 is configured to issue OBD commands 370 to the OBD system user interface 500 when a diagnostic fault is set. In certain implementations, the OBD system user interface 500 includes an MIL, or other indicated, that is illuminated, or otherwise activated, in response to the receipt of an OBD command 370. Additionally, the controller 300 is configured to issue a decomposition tube regeneration command 375 when operating conditions warrant regeneration of the DEF decomposition tube 239. Referring back to FIG2, in certain embodiments, the controller 300 includes a system override module 380. In certain instances, the initiation of a commanded regeneration of the DEF decomposition tube 375 as discussed above may be inhibited by the actions of a user or operator. In such instances, to prevent DEF deposits from growing too large for easy decomposition, the system override module 380 may light the DPF lamp to alert the user of the need for an active regeneration of the DEF decomposition tube 375. The alert can be communicated via a DPF lamp on the dashboard, as opposed to an OBD lamp, such as an MIL. In response to the alert, the user should change whatever action is preventing the initiation of the regeneration event. Operator actions that may prohibit a regeneration event on the DEF decomposition tube 375 can include a regeneration inhibit or disable switch in the ON position, tough duty cycles (e.g., frequent stops and starts) where an aftertreatment system cannot attain the requisite regeneration temperatures.
block diagram
310
diagnostic fault module
375
regeneration command DEF decomposition tube
365
other diagnostic signals
325
request
335
diagnostic interrupt command
350
SCR inlet NOx signal
380
system override module
360
DPF outlet pressure signal
300
controller
355
SCR outlet NOx signal
320
fault mitigation module
370
command commands
395
regeneration frequency module
340
regeneration module
390
modified DEF rate command
330
diagnostic interrupt module
['1. An apparatus (300) for mitigating on-board diagnostic, OBD, faults generated by an OBD system of an internal combustion engine, ICE, system (10) having a selective catalytic reduction system (230) with a diesel exhaust fluid, DEF, decomposition tube (239),  characterized in that  the apparatus comprises: a fault mitigation module (320) configured to monitor at least one OBD signal of the OBD system and issue a request (325) for regenerating the DEF decomposition tube (239) when a value of the at least one OBD signal (352) reaches a predetermined regeneration threshold (353) corresponding with the at least one OBD signal (352), the regeneration threshold (353) being reachable prior to an OBD fault threshold (354) corresponding with the at least one OBD signal (352); and a regeneration module (340) configured to regenerate the DEF decomposition tube (239) according to the issued request (325); characterized in that  the at least one OBD signal comprises at least one of a first OBD signal corresponding with a NO x  conversion efficiency of the selective catalytic reduction system and a second OBD signal corresponding with a particulate matter filter outlet high pressure.', '2. The apparatus of claim 1, further comprising a system override module (380) configured to alert a user of user actions preventing the initiation of a requested regeneration event and implement measures for mitigating consequences of the user actions if the user does not cease the user actions within a predetermined time period.', '3. The apparatus of claim 2, further comprising a diagnostic interrupt module (330) configured to suspend monitoring of the at least one OBD signal (352) in response to the issuance of a request (325) for regenerating the DEF decomposition tube (239), wherein the measures for mitigating consequences of the user actions comprise overriding the suspension of the monitoring of the at least one OBD signal (352) to re-enable the monitoring of the at least one OBD signal (352).']