Abstract: A dosing control system for an exhaust system of an engine includes: a tank containing a reductant solution having urea; an injector operable to inject the reductant solution into an exhaust flow upstream of an SCR apparatus; first and second NOx sensors disposed to sense NOx emissions in the exhaust flow upstream and downstream, respectively, of the SCR apparatus; and a control module. The control module is disposed in signal communication with the first and second NOx sensors and in operable communication with the injector, the control module being operable to set an original dosing level and decrease a dosing of the reductant solution injected by the injector based on a determination from signals received from the first and second NOx sensors that a reduction in a conversion efficiency of the SCR apparatus below a defined level of conversion efficiency has occurred.

Abstract: A monitoring system for a single can oxidation catalyst (OC)/particulate filter (PF) member includes a controller including a first temperature sensor input configured to receive a first exhaust temperature upstream of an OC portion of the single can OC/PF member, a second temperature sensor input configured to receive a second exhaust temperature downstream of the first temperature. The controller is configured and disposed to calculate an exothermic capacity of the OC portion and determine washcoat deterioration of a PF portion of the single can OC/PF member based on the exothermic capacity of the OC portion.

Abstract: A vehicle includes an engine, an exhaust system, and a controller. The exhaust system includes a selective catalytic reduction (SCR) device, and a rear nitrogen oxide (NOx) sensor. The controller, which is in communication with the NOx sensor, includes a processor and tangible, non-transitory memory. A plurality of data maps and a plurality of binary maps are recorded in memory. Each data map is indexed by a different pair of exhaust system performance values. Each cell of each data map is populated by estimated downstream NOx levels. The binary maps are indexed by one of the pairs of exhaust system performance values. Each cell of each binary map is populated by a binary value, i.e., a 0 or 1. The controller uses the data maps and the binary maps to execute a control action with respect to the exhaust system, such as verifying plausibility of the rear NOx sensor.

Abstract: A method of increasing a weighting factor of an exponentially weighted moving averaging (“EWMA”) filter is provided. The method includes monitoring a data stream containing raw data values, and determining an EWMA value based on the data stream by an electronic control module. The method includes determining if the EWMA value is between a predetermined maximum fault threshold value and a predetermined minimum fault threshold value. The method includes increasing the weighting factor of the EWMA filter to more heavily weigh incoming raw data values of the data stream based on the difference between the first raw data value and a previously calculated filtered value exceeding the calibration value.

Abstract: A control method and system for monitoring a selective catalytic reduction (“SCR”) device of an exhaust gas treatment system is disclosed. The method includes monitoring a plurality of operating conditions related to determining an efficiency of the SCR device and a SCR temperature. The method includes determining if each of the operating conditions are within a respective predetermined range and if the SCR temperature is below an operating temperature range. The method includes activating a hydrocarbon supply based on if each of the operating conditions are within the respective predetermined range and if the SCR temperature is below the operating temperature range. The hydrocarbon supply is located upstream of the SCR device to generate heat if activated. The method includes monitoring the SCR temperature to determine if the SCR device is operating within the operating temperature range.

Abstract: A vehicle that includes an engine, an exhaust system, and a controller, and a method are disclosed herein. The exhaust system includes a passage for directing the exhaust gas stream from the engine through the series of exhaust after-treatment devices, including a selective-catalytic reduction device and a diesel particulate filter (DPF). The exhaust after-treatment devices are employed to reduce various exhaust emissions of the engine. The exhaust system, may however, prematurely return failing emissions results due to the amount of contaminants that have flowed through the exhaust system since the last regeneration even of the particulate filter. Therefore, the controller may, via the present method, alter the threshold of the SCR efficiency diagnostic due to contaminants accumulated on the DPF and selectively enable or disable the diagnostic based on a set of recorded instructions, to improve the robustness of the SCR efficiency diagnostic and prevent inaccurate failing emissions results.

Abstract: An exhaust treatment system includes a particulate filter having a filter substrate configured to trap soot contained in exhaust gas. A regeneration system is configured to perform a regeneration operation that regenerates the particulate filter by burning away soot stored in the filter substrate. A control module is in electrical communication with the regeneration system to generate a first control signal that initiates the regeneration operation based on a comparison between at least one operating condition of the exhaust treatment system and a threshold value. The control module generates a second control signal in response to detecting at least one diagnostic signal. The second control signal initiates the regeneration operation independently of the comparison.

Abstract: A method of detecting a thermal event is provided that relies not only on monitored exhaust temperatures, but also on temperature gradients propagating in the direction of exhaust flow. Specifically, the method of detecting a thermal event in a vehicle exhaust system includes monitoring at least one operating parameter at multiple locations spaced in exhaust flow of the vehicle exhaust system. The method then includes initiating a protective action if the monitoring indicates that at least one respective predetermined temperature requirement and a respective predetermined temperature gradient requirement are exceeded at two of the multiple temperature sensor locations within a predetermined time period.

Abstract: A method of monitoring an exhaust treatment system of a vehicle is provided. The method includes: determining a modeled resistance of exhaust flow in the exhaust treatment system; determining a measured resistance of exhaust flow in the exhaust treatment system; evaluating the modeled resistance and the measured resistance to determine a fault status; and generating at least one of a warning signal and a message based on the fault status.

Abstract: Embodiments of the invention include a method for performing diagnostics of a selective catalytic reduction (“SCR”) device in an exhaust gas treatment system of an internal combustion engine. The method includes monitoring an amount of sulfur in the SCR device of the exhaust treatment system and monitoring, by an SCR diagnostics module, an efficiency of the SCR device and indicating when the efficiency of the SCR device falls below an efficiency diagnostics threshold. Based on determining that the amount of sulfur in the SCR device is above a first threshold, the method includes disabling an operation of the SCR diagnostics module.

Abstract: The capacity of a platinum-containing diesel oxidation catalyst (DOC) to simultaneously convert NO to NO2, CO to carbon dioxide, and remaining hydrocarbons to carbon dioxide and water in the exhaust system of a vehicle diesel engine may be evaluated and diagnosed using measured DOC exhaust inlet temperatures and outlet temperatures at a relatively high exhaust temperature and, soon thereafter, at a relatively low exhaust inlet temperature. Values of the platinum-containing DOC exotherms at the high and low DOC inlet temperatures are found to provide a basis for evaluation of both NO conversion and the HC and CO conversion capabilities of the DOC. The process may be repeated as the catalyzed DOC conversion efficiency changes with use. The practice may also be used to evaluate the performance of oxidation catalysts used in a like way in treating the exhaust from a lean-burn gasoline engine.

Abstract: An exhaust gas treatment system includes a particulate filter to collect particulate matter from exhaust gas flowing therethrough. The particulate filter realizes a pressure thereacross in response to the exhaust gas flow. A delta pressure sensor determines a first pressure upstream from the particulate filter and a second pressure downstream from the particulate filter. A delta pressure module is in electrical communication with the delta pressure sensor. The delta pressure module determines a pressure differential value based on a difference between the first pressure and the second pressure and generates a diagnostic signal based on a plurality of the pressure differential values and a predetermined time period.

Abstract: A system and method for initiating an engine after-run state and controlling a nitrogen oxide sensor self-diagnostic tool are provided. The system may include an internal combustion engine, an exhaust system, a selective catalytic reduction (SCR) device and at least two NOx sensors to measure the efficiency of the SCR device and a controller or host machine. The controller, via the present method, executes a first control action to disable the self-diagnostic tool when one of an occurrence of a particulate filter regeneration event and a non-occurrence of a calibration threshold is detected. The controller executes a second control action, initiating an engine after-run state and enabling the self-diagnostic tool when one of a non-occurrence of a particulate filter regeneration event and an occurrence of the calibration threshold is detected.

Abstract: A method of monitoring regeneration of a particulate filter is provided. The method includes evaluating whether a regeneration event is based on a fixed threshold condition; selectively setting a pass or fail status based on the evaluating; and generating a message indicating the pass or fail status.

Abstract: An exhaust gas treatment system includes a particulate filter to collect particulate matter from exhaust gas flowing therethrough. A regeneration module performs a regeneration operation that regenerates the particular filter. The regeneration operation generates an exothermic event which heats the particulate filter above a target temperature that burns the particulate matter. At least one temperature sensor is disposed adjacent the particular filter to determine at least one temperature of the exhaust gas. The exhaust gas treatment system further includes a temperature diagnostic module to determine a temperature profile of the particulate filter based on the temperature of the exhaust gas. The temperature diagnostic module further determines a temperature deviation of the particulate filter based on a comparison between the temperature profile and a target temperature.

Abstract: An oxidation catalyst (OC)/hydrocarbon injector (HCI) testing system includes a controller having a first oxygen sensor input configured and disposed to receive a first oxygen sensor value upstream of an oxidation catalyst (OC) device and a second oxygen sensor input configured to receive a second oxygen sensor value downstream of the OC device. The controller is configured and disposed to perform a first test to detect one of a faulty OC device and a faulty HCI based on a difference between the first and second oxygen sensor values.

Abstract: An internal combustion engine includes a particulate filter that is configured to treat exhaust gas. A method for monitoring the particulate filter includes employing a soot sensor to monitor the exhaust gas downstream of the particulate filter. A fault is detected in the particulate filter when accumulated soot mass indicated by the soot sensor exceeds a soot mass threshold over a course of engine operation between a first regeneration event and a second regeneration event of the particulate filter. A control module associated with operation of the internal combustion engine is notified of the fault.

Abstract: Embodiments of the invention include a method for performing diagnostics of a selective catalytic reduction (“SCR”) device in an exhaust gas treatment system of an internal combustion engine. The method includes monitoring an amount of sulfur in the SCR device of the exhaust treatment system and monitoring, by an SCR diagnostics module, an efficiency of the SCR device and indicating when the efficiency of the SCR device falls below an efficiency diagnostics threshold. Based on determining that the amount of sulfur in the SCR device is above a first threshold, the method includes disabling an operation of the SCR diagnostics module.

Abstract: A dosing control system for an exhaust system includes: a reductant fluid tank operable to contain a reductant solution comprising urea; an injector disposed in operable communication between a reductant tank and an SCR apparatus, the injector being operable to inject the reductant solution from the reductant tank into a flow of exhaust upstream of the SCR apparatus; a urea quality sensor (UQS) configured and disposed to sense a concentration of the urea in the reductant solution; and, a control module disposed in signal communication with the UQS and in operable communication with the injector, the control module being operable to adjust a dosing of the reductant solution injected by the injector based on a concentration of the urea in the reductant solution.

Abstract: A method for assessing NO2 generation efficiency in a diesel engine after-treatment (AT) system having a diesel oxidation catalyst (DOC) downstream of the engine generating the NO2 and a selective catalytic reduction (SCR) catalyst downstream of the DOC converting NOX with the aid of the NO2. Engine exhaust gas flow is passed into the AT system and a reductant is injected into the gas flow between the DOC and the SCR catalyst. SCR inlet gas flow temperature is monitored during transient engine operation and DOC inlet and SCR catalyst outlet NOX concentrations are detected when the SCR catalyst inlet gas flow temperature is in a predetermined range. SCR catalyst NOX conversion efficiency is determined using the detected DOC inlet and SCR catalyst outlet concentrations of NOX. Additionally, whether the NO2 generation efficiency is at or above threshold efficiency is assessed by comparing the determined and threshold NOX conversion efficiencies.