GB2613024A

GB2613024A - System and method for controlling operation of exhaust gas treatment apparatus

Info

Publication number: GB2613024A
Application number: GB2116826.5A
Authority: GB
Inventors: James Eager Anthony; Brian Raymond Max; Krishnakanthan Soundarrajan
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2023-05-24
Also published as: GB202116826D0; WO2023097198A1

Abstract

An engine system (100, fig 1) comprises an engine, a selective catalytic reduction (SCR) module (124, fig 1) and a controller (152, fig 1). A method for controlling operations of the SCR module includes, prior to a time-initiated cleaning event to clear the SCR module of sulphur accumulation, determining 280 whether fuel for combustion in an engine (104, fig 1) comprises a high sulphur content. If fuel with a high sulphur content is determined, a mode of the engine is activated 290 to increase a temperature of an exhaust gas entering into the SCR module to assist with conversion of nitrogen oxides (NOx) such that a rate of drop in an efficiency of the conversion is lowered and the SCR module is allowed to reach up to the time-initiated cleaning event with the efficiency of the conversion being maintained at least equal to or higher than an efficiency threshold.

Description

SYSTEM AND METHOD FOR CONTROLLING OPERATION OF

EXHAUST GAS TREATMENT APPARATUS

TECHNICAL FIELD

[0001] The present disclosure relates to the field of exhaust gas treatment. More particularly, the present disclosure relates to controlling operation of an exhaust gas treatment apparatus, such as a selective catalytic reduction (SCR) module.

Background

[0002] An exhaust gas treatment apparatus general ly includes a number of modules to treat an exhaust gas. For example, an exhaust gas treatment apparatus may include one or more of a diesel oxidation catalyst (DOC) module, a diesel particulate filter ( DP F) module, and a selective catalytic reduction (SC R) module. These modules may be arranged in seri es such that the exhaust gas may flow through each of them for treatment The DOC module may cause constituents of exhaust gas to oxidise; the DPF module may filter soot from exhaust gas in order to prevent the soot from being released into the atmosphere; and the SC R module may cause NOx (nitrogen oxides) present in the exhaust gas to undergo a chemical reaction with ammonia to produce Nitrogen and water.

[0003] A performance or efficiency of each of these modules may decrease with usage. For example, an efficiency of an SCR module may be influenced by an accumulation of sulphur on the SCR module. If a high sulphur fuel is used, an accumulation of sulphur on the S C R module may be even quicker and may result in the deactivation of the SC R module. Commonly, such accumulation may be removed by an SC R cleaning process that involves increasing the temperature of the SCR module. As an example, unburnt fuel may be introduced upstream of the DOC module such that said fuel may be oxidised in the DOC. In so doing, a temperature of the exhaust gas leaving the DOC module and entering the SCR module may be increased and an effective reaction of NOx to produce Nitrogen and water may occur at the SC R module. In an event a high sulphur fuel is used, the need for cleaning the SCR module may be considerably greater than when regular (e.g., I ow sulphur) fuel is used.

[0004] U.S. Patent No. 9,988,999 discloses a system and method for regeneration of an aftettreatment devi ce or component The disclosed method or system employs one or more regeneration modes of operation in which the at least one aftertreatment device is regenerated by obtaining a target condition of an exhaust gas. The regeneration modes of operation can include a combustion phase retardation operating mode, a selected cylinder firing operating mode, a charge flow reduction operating mode, an engine output increase operating mode, an exhaust heating operating mode, and a hydrocarbon dosing operating mode.

SUMMARY

[0005] In one aspect, the disclosure is di rected to a method for controlling operations of a selective catalytic reduction (SCR) module of an engine system. The method includes, prior to a time-initiated cleaning event of the SCR module to clear the SC R module of sulphur accumulation, determining whether fuel for combustion in an engine of the engine system comprises a high sulphur content If fuel with a high sulphur content is determi ned, the method further includes using a control ler to activate a mode of the engine to increase a temperature of an exhaust gas entering into the SC R module to assist with a conversion of nitrogen oxides (N0x) in the exhaust gas at the SCR module such that a rate of drop in an efficiency of the conversion is lowered and the SCR module is allowed to reach up to the time-initiated cleaning event with the efficiency of the conversion being maintained at least equal to or higher than an efficiency threshold.

[0006] In another aspect, the disclosure relates to an engine system. The engine system includes an engine, a selective catalytic reduction (SCR) module for treating exhaust gas released from the engine, and a system for controlling operations of the selective catalytic reduction (SCR) nodule. The system includes a controller, wherein pri or to a ti me-initiated cleaning event of the SCR module to clear the SCR module of sulphur accumulation, the controller is configured to detect whether fuel applied for combustion in the engine comprises high sulphur content When fuel with high sulphur content is detected, the controller is configured to activate a mode of the engine to increase a temperature of the exhaust gas entering into the SCR module to assist with a conversion of nitrogen oxides (N Ox) in the exhaust gas at the SCR module such that a rate of drop in an efficiency of the conversion is lowered and the SCR module is allowed to reach up to the time-initiated cleaning event with the efficiency of the conversion being maintained at least equal to or higher than an efficiency threshold.

[0007] A machine, such as a large truck, an off-road truck, a bulldozer, an excavator, a tracked vehicle, and/or the like, often include an engine that for example, may be powered by combusting fuel (e.g., diesel fuel). Owing to various factors, such as a region in which the machine operates, a fuel employed in the machine may be of a low quality and may possess high sulphur content A fuel with high sulphur content may significantly affect a working and operable life of an aftertreatment device (e.g., an SCR module) associated with the engine of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic view of an exemplary engine system, in accordance with

an embodiment of the present disclosure;

[0009] FIG. 2 illustrates an exemplary method for controlling operations of a selective catalytic reduction (SCR) module of the engine system in accordance with an embodiment of the present disclosure; and [0010] FIGS. 3 to 6 are trend charts of an efficiency data associated with an efficiency of the SC R module in various scenarios, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0011] Reference will now be made in detail to specific embodiments or features, examples of which are illustrated i n the accompany i ng drawings. Generally, correspondi ng reference numbers may be used throughout the drawings to refer to the same or corresponding parts, e.g., 1, 1 1 ", 101 and 201 could refer to one or more comparable components used in the same and/or different depicted embodiments.

[0012] Referring to FIG. 1, an engine system 100 is shown. The engine system 100 may include an engine 104 (e.g., an internal combustion engine) and an aftertreatment system 108 for the engine 104. The engine system 100 may be applied in machines, such as such as articulated trucks, off-highway trucks, bulldozers, excavators, tracked vehicles, loaders, and/or the like. T he engine system 100 may be also applied in stationary machines, such as generator sets applicable in domestic and commercial establishments. The engine 104 may include a one or more cylinders (not shown) within which a fuel may be supplied for combustion. The fuel may include, but not limited to, diesel fuel, any derivative of diesel fuel, or any other combustible fuel which may potentially include sul phur content Said fuel when received into the cylinders of the engine 104 may be combusted for the production of motive power. Once the fuel is combusted, burnt residual constituents of the fuel may be released into the aftertreatment system 108 as exhaust gas.

[0013] The aftertreatment system 108 includes one or more aftertreatment apparatuses 112 to treat exhaust gas. The aftertreatment apparatuses 112 may include a diesel oxidation catalyst (DOC) module 116, a diesel particulate filter (DPF) module 120, and a selective catalytic reduction (SC R) module 124. According to an exemplary embodiment, exhaust gas may flow through each of the DOC module 116, the DPF module 120, and the SC R module 124, in the exemplary sequence of the aftertreatment apparatuses 112 as they are listed here. In that manner, the exhaust gas released from the engine 104 may be treated before being released into the atmosphere 128. As an example, the DOC module 116 may cause certain constituents of the exhaust gas to oxidise; the DPF module 120 may filter soot from the exhaust gas in order to prevent soot from being released into atmosphere 128; and the SC R module 124 may cause nitrogen oxides ( i.e., N Ox) present in the exhaust gas to undergo a conversion or a chemical reaction with ammonia to produce Nitrogen and water. Said ammonia may be maintained in an ammonia tank 132 and injected at the SCR module 124 through an ammonia injector 136. A skilled person may readily understand that aspects of the present disclosure are applicable to a wide range of exhaust gas treatment apparatuses, and they are not limited to the examples described herein, which are provi ded simply for assisting the reader in understanding one exemplary context of the present disclosure.

[0014] Performance of each of the aftertreatment apparatuses 112 may reduce overtime and with use. For example, performance or efficiency of the SCR module 124 may be influenced by sulphur accumulation on the SC R module 124. If high sulphur fuel is used, sulphur accumulation on the SC R module 124 may be relatively quick and the efficiency of the SC R module 124 may also reduce commensurately.

[0015] With regard to determi ni ng the efficiency of the SCR module 124, in one example, the engine system 100 may include a pair of NOx sensors. One NOx sensor (e.g., a first NOx sensor 140) may be located upstream of the SCR module 124 and the other NOx sensor (e.g., a second NOx sensor 144) may be located downstream of the SC R module 124. An indication of the efficiency of the SCR module 124 may be derived from said pair of NOx sensors 140, 144. For example, a difference between the values of NOx sensed by the NOx sensors 140, 144, at any given point may indicate the efficiency of the SC R module 124 or an efficiency of conversion of NOx at the SCR module 124 may be derived. For ease in understanding and reference, said efficiency of conversion may be referred to as:efficiency data herei nafter.

[0016] Further, sulphur that accumulates on the SC R module 124 may be removed by an SCR cleaning process or an SCR cleaning event to improve the efficiency data. During operation of the engine 104, a number of such SCR cleaning event may be implemented, for example, in regular intervals. For the purposes of the present disclosure, cleaning events implemented in regular time intervals may be referred to as time-initiated cleaning events. One or more aspects of the present disclosure also discusses another type of cleaning event in which a cleaning event may be implemented based on the fall ing efficiency data -such a cleaning event may be referred to as threshold-initiated cleaning events, i.e., in which a cleaning event is implemented upon the efficiency data falling below a first predefined efficiency threshold.

[0017] According to an aspect of the present disclosure, an SC R cleaning event involves increasing the temperature of the SCR module 124 so as to result in the cornbusli on and clearing of the sulphur accumulation from the SCR module 124. To do 5Q a temperature of the exhaust gas entering the SCR module 124 may be increased by one or more methods. A first method may include hydrocarbon dosing (HCD) or supplying and introduci ng fuel (i.e., unburnt fuel) (e.g., the same fuel that is used in the engine 104 for combustion and the generation of motive power) upstream of the DOC module 116 for oxidation at the DOC module 116. In so doing, a temperature of the exhaust gas leaving or exiting the DOC module 116 and then entering the SC R module 124 may be elevated and a temperature at the Sc R module 124 may be i ncreased. A second method may include injecting fuel (i.e., unburnt fuel) into one or more cylinders of the engine 104 during a non-combustion period of the engine 104, such that the injected fuel is released unburnt out of the cylinders of the engine 104 so as to be combusted and oxidised at the DOC modul e 1 1 6. In so doing, a temperature of the exhaust gas leaving or exiting the DOC module 116 and then entering the SCR module 124 may be raised and accordingly a temperature at the SC R module 124 may be increased.

[0018] According to an aspect of the present disclosure, a system and method for controlling operations of the SC R module is discussed further below. The system is indicated and or referred to as system 148. The method is executable by the system 148 and is discussed later below by way of a flowchart 200 provided in FIG. 2. T he system 148 includes a controller 152 that may be communicably coupled to the engine 104 to control various aspects of a working of the engine 104. The controller 152 may also be communicably coupled to one or more of the modules (e.g., the SC R module 124) and the NOx sensors 140, 144. Additionally, or optionally, the controller 152 may also be communicably coupled to the ammonia injector 136 and to a device (e.g., an ammonia quality sensor 156) that may provide an indication of a quality of the ammonia in the ammonia tank 132. The controller 152 may be configured to run a set of instructions based on which the method may be performed. In some embodiments, the method may be in operation whenever the engine 104 is active or in operation. Alternatively, there may be provisions to move or switch the method to an inactive state while the engine 104 is in operation, if an operator of the engine system 100 desires to do so.

[0019] The controller 152 may be communicably coupled to or may be one and the same as the engine system -s electronic control module(ECM). Alternatively, the controller 152 may be configured as a stand-alone entity. Further, the controller 152 may be a microprocessor-based device, and/or may be envisioned as an application-specific integrated circuit or other logic devices, which provide controller functionality, and such devices being known to those with ordinary skill in the art. In one example, it is possible for the controller 152 to include or be representative of one or more controllers having separate or integral ly configured processing units to process a variety of data (or input or commands). In some embodiments, a transmission of data between the control ler and various other devices (e.g., the SCR module 124 and the NOx sensors 140, 144) may be facilitated wi rel essly or through a standardized CA N bus protocol. Further, the controller 152 may be optimally suited for accommodation within certain panels or portions of the engine system 100 from where the controller 152 may remain accessible for ease of use, service, calibration, and repairs.

[0020] Processing units of the controller 152, to convert and/or process various input command signals, and/or the like, may include, but are not limited to, an X86 processor, a Reduced Instruction Set Computing (RISC) processor, an Application Specific Integrated Circuit (ASIC) processor, a Complex Instruction Set Computing (CISC) processor, an A c:ktanced RISC Machine (A R M) processor, or any other processor.

[0021] Examples of a memory configured within the controller 152 may include a hard disk drive (HDD), and a secure digital (SD) card. Further, such a memory may include non-volatiletvolatile memory units such as a random-access memory (RAM) /a read only memory (ROM), which may include associated input and output buses. Said memory may be configured to store various other instruction sets for various other functions of the engine system, along with the set of instruction, discussed above.

Industrial Applicability

[0022] Referring to FIG. 2, the flowchart 200 is discussed. FIGS. 3 to 6 are also discussed in conjunction with the discussions that relate to the flowchart 200. The flowchart 200 includes a number of steps.

[0023] At a first step 210, the controller 152 may receive an efficiency data associated with the SCR module 124. In some embodiments, the controller 152 may itself compute the efficiency data by using and comparing values of NOx obtained from the NOx sensors 140, 144. For example, greater the difference between the values of the NOx sensors 140, 144, better or higher may be the conversion of NOx in the exhaust gas at the SC R module 124, and correspondingly, better or higher may be the efficiency data. Although not limited, in operation, the efficiency data may be computed and/or generated on a continuous basis. In some embodiments, the efficiency data may be converted to percentages or appropriate values so as to be outputted and be comprehensible to one or more operators of a machine in which the engine system 100 may be applied.

[0024] At step 220, the controller 152 may detect whether there is any I oweri ng or a reduction in the efficiency data. More particularly, the controller 152 may detect if any reduction in the efficiency data (caused, for example, by one or more of an accumulation of sulphur, high sulphur fuel, prolonged usage, and the like) is such that the efficiency data drops below a first predefined efficiency threshold 160 (see FIGS. 3 to 6).

[0025] In the event the controller 152 deterrri nes the efficiency data has not fallen below the first predefined efficiency threshold 160, the method moves to step 230 at which step, the controller 152 may determine if a time interval, T, since any previous SCR cleaning event (e.g., a ti ire-initiated cleaning event) or since the start of the engine 104 has elapsed. In the event that the time interval, T, has not elapsed, the method returns to step 210.

[0026] In the event the time interval, T, has elapsed and/or passed, the method moves to step 240, at which step, the controller 152 may implement a ti ire-initiated SC R cleaning event. As an example, the time-initiated SC R cleaning event may occur every 60 hours. In other words, the time interval, T, may be exemplarily equal to 60 hours. Once the time-initiated cleaning event is concluded, the method returns to step 210.

[0027] The aforementioned operation, as discussed so far, relates to a scenario when the SC R module 124 is operati ng as expected in regular operation, e.g., using regular (low sulphur) fuel. Notably, in such a scenario, the method may remain within the bounds of the flowchart 200 that is delimited by the dashed boundary 244.

[0028] FIG. 3 shows an example trend chart 300 of the efficiency data (e.g., in percentages) against time (e.g., in hours) when the method is operating within the dashed boundary 244 of the flowchart 200 of FIG. 2. In the example trend chart 300 of FIG. 3, the effici ency data, as shown, does not fall below the first predefi ned efficiency threshold 160. As may be noted, the trend chart 300 of FIG. 3 covers a period including two SC R cleaning events (e.g., two time-initiated cleaning events as correspondingly indicated by the period between time, B, and time, C, and the period between time, D, and ti me, E), which exemplarily occur at 60 hour intervals. T hus, for the trend chart 300 of the efficiency data in FIG. 3, the ti me interval, T, is exemplarily 60 hours.

[0029] Notably, in FIG. 3, engine operation begins at time, A; a first time-initiated cleaning event begins at time, B, (that is after 60 hours of engine operation, e.g., from ti me, A); the first time-initiated cleaning event concludes at time, C; a second time-initiated cleaning event begins at time, D, (that is after 60 hours of engine operation, e.g., from ti me, C); and the second time-initiated cleaning event concludes at time, E. After each of the time-initiated cleaning events, it may be noted that the efficiency data returns to approximately an efficiency data as seen after (e.g., immediately after) any previous SC R cleaning event [0030] In an event a high sulphur fuel is used, the efficiency data may reduce rapidly such that the regular cleaning events at the predefined time interval, T, to clean the SCR module 124, may be insufficient. Referring again to FIG. 2, at step 220, and prior to a next, time-initiated cleaning event, if the controller 152 determines a drop in the efficiency data to below the first predefined efficiency threshold 160, the method may move to step 250, at which step, the controller 152 may exemplarily check if the ammonia, configured to be injected into the SC R module 124, is too dilute or not (e.g., by reading values from the ammonia quality sensor 156) and/or if the ammonia injector 136 is blocked. If such a check is posi tive ( i.e., if the controller 152 determines that the ammonia is indeed too di lute and/or the ammonia injector 136 is blocked), then the controller 152 may infer that the reason for low, fallen efficiency data is one or more of a low quality of ammonia or a faulty ammonia injector operation, rather than inferring that the fuel has a high sulphur content, and so the method returns to step 210.

[0031] If the aforementioned check is negative (i.e., if the controller 152 determines that neither is the ammonia too diluted and nor is the ammonia injector 136 blocked), the method moves to step 260, at which step, the controller 152 implements the threshold-i niti ated cleaning event of the SCR module 124. The threshold-initiated cleaning event may occur regardless of the ti me internal, T, and/or the ti me passed since any previous SC R cleaning event or the start of the engine 104. Also, it may be noted that the threshold-initiated cleaning event may be identical (in function and working) to the time-initiated cleaning event [0032] Following a start of the threshold-initiated cleaning event at step 260, at step 270, the controller 152 may check if the efficiency data has recovered to exceed a second predefined efficiency threshold 164 (see FIG. 4). The second predefined efficiency threshold 164 may be higher than the first predefined efficiency threshold 160. If the efficiency data does not exceed the second predefined efficiency threshold 164, it may not be inferred that the reason for the low efficiency data is due to the use of high sulphur fuel, and, rather, the controller 152 may infer that the low efficiency data may be caused by other factors associated with a working of the aftertreatment system 108 (e.g., a faulty SCR module, etc.), and so the method returns to step 210.

[0033] In the event the controller 152 detects that the efficiency data attained by the threshold-initiated cleaning event exceeds the second predefi ned efficiency threshold 164, the method moves to step 280, at which step, the conVol I er 152 may detect or determine that the fuel applied for combustion has a high sulphur content and, in response, the controller 152 may output a high sulphur fuel warning or alert. In some embodiments, the warning or alert may be outputted through an output device (not shown), such as a display device, lighting device, audio alert device, and the like. For example, the high sulphur warning may include one or more of: a visible and/or audio warning outputted to an operator, a service engineer, a fleet operator, or to any stakeholder of the engine system 100, so as to indicate to them that the fuel has a high sulphur content [0034] At step 290, in response to the determination of the fuel to have high sulphur content and/or in response to the high sulphur vvaming or alert the controller 152 may activate a mode, e.g., a thermal management mode. The mode helps to increase a temperature of the exhaust gas entering into the Sc R modul e 124 to assist with a conversion of nitrogen oxides (N0x) in the exhaust gas at the SC R module 124 such that a rate of drop in an efficiency of the conversion (or a rate of drop in the efficiency data) (owing to the high sulphur content in the fuel) is lowered and the SC R module 124 is al lowed to reach up to the next time-initiated cleaning event. For example, the SC R module 124 may be allowed to reach up to the next tine-initiated cleaning event with the efficiency of the conversion (or the efficiency data) being maintained at least equal to or higher than an efficiency threshold (e.g., a primary efficiency threshold 168, see FIGS. 3 to 6). Although not limited, said primary efficiency threshold 168 may be a predetermined value of efficiency and may be equal to the first predefined efficiency threshold 160.

[0035] In some embodiments, activating the mode includes altering one or more operational parameters of the engine 104. For example, the operational parameters may include a load associated with the engine 104 and altering the operational parameters may include increasing the load associated with the engine 104. An increase in the load on the engine 104 may include connecting one or more parasitic loads (e.g., an electric load, a hydraulic load, etc.) to the engine 104. In some embodiments, the operational parameters may include an injection of the fuel into the engine 104 to power the engine 104 and altering the parameters may include increasing the injection of the fuel into the engine 104. Such altering of parameters raises the temperature of the exhaust gas exiting the engine 104 and entering the aftertreatment apparatuses 112.

[0036] Referring to FIG. 4, a graph or a trend chart 400 of the efficiency data (e.g., in percentages) against ti me (e.g., in hours) in an event that high sulphur fuel is used, is shown. Operation of the engine 104 begins at lime, A. Efficiency data drops rapidly such that efficiency data drops below the first predefined efficiency threshold 160 at time, F, i.e., before time interval, T, (e.g., well before 60 hours of engine operation) has elapsed. As a result, the controller 152 (at step 260 in FIG. 2) triggers and implements the threshold-initiated cleaning event. In FIG.4, thethreshold-initiated cleaning event (which takes place between lime, F, and ti me, G) results in the efficiency data to return towards the efficiency data seen at the start of the session of operation of the engine 104 (e.g., compare time, A, and ti me, G, in FIG. 4), and, in process, may also result in the efficiency data exceeding the second predefined efficiency threshold 164 (which the controller 152 determines at step 270 of FIG. 2). At ti me, G, or as soon as the efficiency data exceeds the second predefined efficiency threshold 164, the controller 152 determines that the fuel applied for combustion i n the engine 104 to be having high sulphur content and outputs a high sulphur fuel warning (i.e., at step 280 in FIG. 2). Also, the controller 152 may halt the threshold-initiated cleaning event at the time, G, or as soon as the efficiency data exceeds the second predefined efficiency threshold 164.

[0037] Once the controller 152 halts the threshold-initiated cleaning event at the time, G, the controller 152 may activate the mode (i.e., step 290 in FIG. 2). Given that the mode may i ncl udetaki ng steps to increase the temperature of the SC R module 124, the mode may in turn cause a reduction in the rate of drop of the efficiency data. Hence, in the trend chart 400 of FIG. 4, the gradient of the plot of the efficiency data between time, G, and ti me, B is lesser than the gradient of the plot of the efficiency data between ti me, A, and time, F. As noted above, the mode may allow the SCR module 124 to reach up to the ti me-initiated cleaning event (i.e., the next ti me-initiated cleaning event indicated by the plot of the efficiency data between time, B and time, C) with the efficiency of the conversion being maintained at least equal to or higher than an efficiency threshold (e.g., the primary efficiency threshold 168).

[0038] Referring to FIG. 5, in some embodiments, the controller 150 may also deactivate the mode (e.g., to save fuel) during a run up to the next, time-initiated cleaning event. Said deactivation may be performed by the controller 152 if the efficiency of the conversion or if the efficiency data remains above a secondary efficiency threshold 172 for a predetermi ned duration. As may be noted from FIG. 5, the secondary efficiency threshold 172 is represented by a dotted line in FIG. 5 and, exemplarily, may be higher than the primary efficiency threshold 168. In some embodiments, the dotted line representing the secondary efficiency threshold 172 may acquire a position at least about midway (or relatively higher than the midway) between the lines indicating the primary efficiency threshold 168 and the second predefined efficiency threshold 164 in the trend chart 500 of the efficiency data of FIG. 5.

[0039] An exemplary manner of determining the predetermined duration and the secondary efficiency threshold 172 is now discussed. In the trend chart 500 of the efficiency data shown in FIG. 5, the controller 152 may determine that a plot of a falling efficiency data (i.e., when neither the mode, nor the SCR cleaning event is active), for any given point on a plot of the efficiency data between time, A, and time, C, may be similar (and thus parallel) to the plot between time, A, and time, F. With said plot of the falling efficiency data in store, the controller 152 may apply (e.g., by superimposing) the plot of the falling efficiency data corresponding to a number of points along the plot from lime, G, to a ti me, I. As an example, the controller 152 may apply the plot of the falling efficiency data corresponding to time, I, and may determi ne that the plot of the falling efficiency data, starting from time, I, would either remain above the primary efficiency threshold 168 or would meet the primary efficiency threshold 168, but would refrain (e.g., certainly) from dropping below the primary efficiency threshold 168 before the start of the next, lime-initiated cleaning event. Accordingly, the controller 152 may infer that even if the mode were deactivated at time, I, or thence onwards any time up until time, B" (i.e., prior to the SC R module 124 reaching up to the next ti me initiated cleaning event), the efficiency data of the SCR module 124 would not drop or recede below the primary efficiency threshold 168. Therefore, the controller 152 may deactivate the mode at time, I, or at any time between time, I, and time, B ", for a remainder of the corresponding interval. In some embodiments, the controller 152 may determi ne the predetermined duration as the time span between time, G, and time, I, and the secondary efficiency threshold 172 as the percentage of efficiency that corresponds to ti me, I. The controller 152 may similarly al so determine predetermined durations and secondary efficiency thresholds for one or more subsequent intervals of operation of the SCR modul e 124.

[0040] In the trend chart 500 of the efficiency data of FIG. 5, the plot of the efficiency data moves from time, I, to time, B", with time, B", indicating a poi nt on the primary efficiency threshold 168. Further, time, B' al so indicates a start of the next time-initiated cleaning event -i.e., time, B ", to lime, C, represents the next ti me-i nitiated cleaning event In some embodiments, the mode may be deactivated only when at least 80% of the interval (e.g., 80% of the 60 hour period) is over.

[0041] In some embodiments, the control I er 152 may also re-activate the mode if either the efficiency of the conversion (i.e., the efficiency data) drops below the primary efficiency threshold 168, or if a rate of drop in the efficiency of the conversion exceeds a predefined rate threshold after deactivating the mode.

[0042] FIG. 6 shows a graph or a trend chart 600 of the efficiency data against time in an event that high sulphur fuel is used. Said trend chart 600 of the efficiency data in FIG. 6 illustrates another scenario. In the trend chart 600 of the efficiency data, operation of the engine 104 begins at time, A. Efficiency data drops rapidly such that efficiency data drops below the first predefi ned efficiency threshold 160 before ti me interval, T, (e.g., well before 60 hours of engine operation) has elapsed. As a result the controller 152 triggers and implements a threshold-initiated cleaning event (i.e., at step 260 in FIG. 2). As with the discussion in FIGS. 4 and 5, in FIG. 6, the threshold-initiated cleaning event (which takes place between ti me, F, and time, G) results in the efficiency data to return towards the efficiency data seen at the start of the session of operation of the engine (e.g., compare time, A, and time, G), and, in process, may also result in the efficiency data exceeding the second predefined efficiency threshold 164 (which the controller 152 determines at step 270 of FIG. 2). At ti me, G, the controller 152 determines a high sulphur fuel and outputs a high sulphur fuel warning (i.e., at step 280 in FIG. 2). Also, the controller 152 may halt the threshold-initiated cleaning event at the time, G, or as soon as the efficiency data exceeds the second predefi ned efficiency threshold 164.

[0043] Once the controller 152 halts the threshold-initiated cleaning event the controller 152 may activate the mode (i.e., step 290 in FIG. 2). Given that the mode may include taking steps to increase the temperature of the SCR module 124, the mode may in turn cause a reduction in the rate of drop of the efficiency data. Hence the gradient of the plot between time, G, and time, H, is lesser than the gradient of the plot between time, A, and time, F. While the difference in the gradient may reduce or lower the rate of drop in the efficiency data, the controller 152, in some embodiments, may extrapolate the plot between time, G, and lime, H, and determine if the manner of the rate of drop in the efficiency data is sufficient to allow the SCR module 124 to reach up to the next lime-initiated cleaning event. In the case of the exemplary trend chart 600 in FIG. 6, the controller 152 may extrapolate and determine that at time, J, the plot between time, G, and time, H, may meet or intersect with the primary efficiency threshold 168, and thence may potentially drop or recede further below the primary efficiency threshold 168, before the completion of time interval, T (or before the exemplary 60 hour period or without reaching up to the next time-initiated cleaning event). In such a scenario, the controller 152 may determine that the mode, in its manner of working, may fail to allow the SCR module 124 to reach up to said next, time-initiated cleaning event without the efficiency data being maintained at least equal to or higher than the primary efficiency threshold 168.

[0044] In response to such a scenario, the controller 152 may further alter the operational parameters of the engine 104. For example, the controller 152 may further increase or connect additional load to the engine 104 and/or further increase the injection of the fuel into the engine 104 so as to increase (e.g., proportionately) the temperature of the exhaust gas exiting the engine 104. In so doing, the controller 152 may help further increase the temperature of the SC R module 124, cause more NOx at the SC R module 124 to undergo conversion, and thereby improve the efficiency data to an extent (see plot between time, H, and ti me, B") allowing the SCR module 124 to reach up to said next, time-initiated cleaning event (see plot between time, B and time, C) with the efficiency of the conversion being maintained at least equal to or higher than the primary efficiency threshold 168.

[0045] Further, in some embodiments, a temperature at the SCR module 124 during a period when the mode is an activated state may be lower than a temperature at the SCR module during a period when the time-i nitiated cleaning event or the threshold-initiated cleaning event is active or in process. For example, the temperature at the SCR module 124 during a period when the mode is an activated state may be between 2756C to 3256C and the temperature at the SCR module 124 during a period when the time-initiated cleaning event or the threshold-initiated cleaning event is in process may be between 4506C to 5006C.

[0046] With the above discussed method, even when a fuel with high sulphur content is used to power the engine 104, the efficiency data of the SCR module 124 may be maintained above a threshold (e.g., above the primary efficiency threshold 168) for a considerable period, thus improving a working of the SCR module 124 and its aftertreatment performance (i.e., conversion of NOx in the exhaust gases into nitrogen and water). The system and method, as described above, prevents derati ng of the aftertreatment system' s overall performance and provides the operator, firstly, with the indication of the the fuel with the high sulphur content, and, secondly, a mechanism by which said fuel may be used up until a better quality fuel (e.g., a fuel with relatively lower sulphur content) is avai labia A I so, the system and method, as discussed herein, allows the SC R module 124 to reach up to the next opportunity to clean itself (e.g., via hydrocarbon dosing) without significantly affecting its conversion efficiency.

[0047] It will be apparent to those skilled in the art that various modificati ons and variations can be made to the system of the present disclosure without departing from the scope of the di scl osure. Other embodi ments will be apparent to those skilled in the art from consi derati on of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.

Claims

C I ai ms What is claimed is: 1. A method for controlling operations of a selective catalytic reduction (SC R) module of an engine system the method comprising: prior to a time-initiated cleaning event of the SC R module to clear the SCR module of sulphur accumulation, determi ning whether fuel for combustion in an engine of the engine system comprises a high sulphur content and if fuel with a high sulphur content is determined, using a controller to activate a mode of the engine to increase a temperature of an exhaust gas entering into the SC R module to assist with a conversion of nitrogen oxides ( N Ox) in the exhaust gas at the SC R module such that a rate of drop in an efficiency of the conversion is lowered and the SCR module is allowed to reach up to the time-initiated cleaning event with the efficiency of the conversion being maintained at least equal to or higher than an efficiency threshold.
2. The method of claim 1, wherein activating the mode includes altering one or more operational parameters of the engine, wherein the one or more operational parameters include a load associated with the engine and altering the one or more operational parameters includes increasing the load associated with the engine.
3. The method of claim 1, wherein activating the mode includes altering one or more operational parameters of the engine, wherein the one or more operational parameters include an injection of the fuel into the engine to power the engine and altering the one or more operational parameters includes increasing the injection of the fuel into the engine.
4. The method of claim 1, wherein determining the fuel to be having high sulphur content includes detecting, by the controller, the efficiency of the conversion of NOx to drop below a first predefi ned efficiency threshold; implementing, by the controller, a threshold-i nit ated cleaning event of the SCR modul e; and determining, by the controller, the fuel to be having high sulphur content if the efficiency of the conversion attained by the threshold-initiated cleaning event exceeds a second predefi ned efficiency threshold.
5. The method of claim 4, wherein the second predefined efficiency threshold is higher than the first predefined efficiency threshold and the threshold-initiated cleaning event is identical to the ti me-i nitiated cleaning event.
6. The method of claim 1, wherein the efficiency threshold is a primary efficiency threshold, the method further comprising deactivating, by the controller, the mode if the efficiency of the conversion remains above a secondary efficiency threshold for a predetermined duration.
7. The method of claim 6, wherein the secondary efficiency threshold is higher than the primary efficiency threshold.
8. The method of claim 6 further comprising re-activating, by the control ler, the mode if either the efficiency of the conversion drops below the primary efficiency threshold, or a rate of drop in the efficiency of the conversion exceeds a predefi ned rate threshold after deactivating the mode.
9. The method of claim 1, wherein a temperature at the SCR module during a period when the mode is an activated state is lower than a temperature at the SCR module during a period when the ti me-initiated cleaning event is in process.
10. The method of claim 1, wherein one or more of the time-initiated cleaning event and the threshold-initiated cleaning event includes one or more of: supplying the fuel upstream of a diesel oxidation catalyst (DOC) module for oxidation at the DOC module to increase temperature of the exhaust gas exiting the DOC module and entering the SCR nodule; and injecting the fuel into one or more cylinders of the engine during a non-combustion period of the engine, such that the fuel injected is released out of the engine to be combusted and ox i di sed at the DOC module to increase temperature of the exhaust gas exiting the DOC module and entering the SCR module.
11. An engine system, comprising; an engi nc a selective catalytic reduction (SC R) module for treating exhaust gas released from the engine; a system for control! i ng operations of the selective catalytic reduction (SC R) module, the system including: a controller, wherein prior to a time-initiated cleaning event of the SCR module to clear the SCR module of sulphur accumulation, the controller is configured to: detect whether fuel applied for combustion in the engine comprises high sulphur content and when fuel with high sulphur content is detected activate a mode of the engine to increase a temperature of the exhaust gas entering into the SCR module to assist with a conversion of nitrogen oxides ( N Ox) in the exhaust gas at the SCR nodule such that a rate of drop in an efficiency of the conversion is lowered and the SCR module is all owed to reach up to the time-initiated cleaning event with the efficiency of the conversion being maintained at least equal to or higher than an efficiency threshold.
12. The engine system of claim 11, wherein to activate the mode the control ler is configured to alter one or more operational parameters of the engine, wherein the one or more operafional parameters include a load associated with the engine and altering the one or more operational parameters includes increasing the load associated with the engine.
13. The engine system of claim 11, wherein to activate the mode the control ler is configured to alter one or more operational parameters of the engine, wherein the one or more operational parameters include an injection of the fuel into the engine to power the engine and altering the one or more operational parameters includes increasing the injection of the fuel into the engine.
14. The engine system of claim 11, wherein to determine the fuel to be having high sulphur content the controller is configured to: detect the efficiency of the conversion of NOx to drop below a first predefined efficiency threshold; i mplement a threshold-initiated cl eani ng event of the SC R module; and determine the fuel to behaving high sulphur content if the efficiency of the conversion attained by the threshold-initiated cleaning event exceeds a second predefined efficiency threshold.
15. The engine system of claim 14, wherein the second predefi ned efficiency threshold is higher than the first predefined efficiency threshold and the threshold-initiated cleaning event is identical to the time-initiated cleaning event
16. The engine system of claim 11, wherein the efficiency threshold is a primary efficiency threshold, the controller configured to deactivate the mode if the efficiency of the conversion remains above a secondary efficiency threshold for a predetermined duration.
17. The engine system of claim 16, wherein the secondary efficiency threshold is higher than the pri mary efficiency threshold.
18. The engine system of claim 16, wherein the controller is configured to re-activate the mode if either the efficiency of the conversion drops below the primary efficiency threshold, or a rate of drop in the efficiency of the conversion exceeds a predefined rate threshold after deactivating the mode.
19. The engine system of claim 11, wherein a temperature at the SCR module during a period when the mode is an activated state is lower than a temperature at the SC R module during a period when the time-initiated cleaning event is in process.
20. The engine system of claim 11, wherein one or more of the tine-initiated cleaning event and the threshold-initiated cleaning event includes one or more of: supplying the fuel upstream of a diesel oxidation catalyst (D 0 C) module for oxidation at the DOC module to i ncrease temperature of the exhaust gas exiting the DOC module and entering the SCR modul e; and injecting the fuel into one or more cylinders of the engine during a non-combustion period of the engine, such that the fuel injected is released out of the engine to be combusted and oxidised at the DOC module to increase temperature of the exhaust gas exiting the DOC module and entering the SCR module.