Method for controlling a power machine system
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- PERKINS ENGINES CO LTD GES NACH DEM RECHT DES VERIGTEN KONIGREICHS
- Filing Date
- 2016-04-12
- Publication Date
- 2026-07-09
Smart Images
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Abstract
Description
Technical field
[0001] This disclosure relates to a method for controlling a power machine system with an aftertreatment module and a reducing agent injector provided therein. The injection of a reducing agent fluid by the reducing agent injector is controlled in such a way as to reduce the formation of solid reducing agent deposits on the reducing agent injector during low-stress cycles. background
[0002] Engine systems for vehicles and the like may include an aftertreatment module for removing unwanted gas emissions or pollutants from the exhaust gases of an internal combustion engine. In particular, a selective catalytic reduction (SCR) system may be provided in the exhaust stream to remove nitrogen oxides (NOx). An SCR system may include a reducing agent injector positioned upstream of a catalyst, and the reducing agent injector may inject a liquid reducing agent into the exhaust gases before they contact the catalyst. Suitable liquid reducing agents may include anhydrous ammonia, aqueous ammonia, and urea. The high temperature of the exhaust gases can vaporize the liquid reducing agent, and upon contact with the catalyst, the gaseous reducing agent can react with the NOx in the exhaust gas to form nitrogen and water.
[0003] However, if the exhaust gas temperature is too low, such as during low-load engine operation and in low-stress cycles, the reducing agent can deposit as solid components on components of the SCR system. In particular, the reducing agent can deposit on, in, or around an outlet nozzle of the reducing agent injector if eddy currents in the exhaust gas flow carry the injected reducing agent back towards the outlet nozzle. Additionally, small amounts of reducing agent can unintentionally escape from the reducing agent injector onto the outlet nozzle, especially if it is fully pressurized. Since the outlet nozzle can have a relatively low surface temperature due to the low exhaust gas temperature, the recirculated and escaped reducing agent can condense on it, and the liquid components of the reducing agent can evaporate.Solid reducing agent deposits can subsequently remain in or on the outlet nozzle, which can therefore become partially or completely clogged. This can lead to increased growth of the reducing agent deposit and result in reduced conversion efficiency of the SCR system. Furthermore, the reducing agent injector can be flushed (cleaned) with exhaust gas to remove any residual reducing agent fluid from the injector and its supply line. Partial or complete blockages can reduce the efficiency of the flushing (cleaning) cycles, potentially causing residual reducing agent fluid to become fixed or crystallized within the injector.
[0004] Power engine systems can therefore be designed to minimize solid reducing agent deposits during low engine loads and low-stress cycles. For example, the exhaust gas temperature can be kept relatively high to prevent the reducing agent injector surface from becoming too cold. Furthermore, the power engine system can be arranged to provide a high exhaust gas flow rate, and / or the internal routing can be optimized to prevent eddy currents. The design of the reducing agent injector can also be optimized to prevent leakage or escape of the reducing agent fluid.However, a power machine system must be designed to operate across an entire range of stress cycles and power machine loads, and such designs of the power machine system may not be suitable for cycles with medium and high stress. Summary
[0005] The present disclosure provides a method for controlling a power engine system, wherein the power engine system comprises: an exhaust aftertreatment module for receiving exhaust gas from an internal combustion engine, the exhaust aftertreatment module comprising a reducing agent injector that is selectively actuated to inject a reducing agent fluid from an injector outlet into the exhaust aftertreatment module, and a control system configured to control a reducing agent fluid injection from the reducing agent injector in one of several different operating modes, the several different operating modes comprising: a first operating mode with injection of reducing agent fluid according to a first set of injection parameters to react with and substantially reduce one or more components of the exhaust gas in the exhaust aftertreatment module,and a second operating mode with injection of reducing agent fluid according to a second injection parameter set for expelling solid reducing agent deposits that have formed above the injector outlet, the method comprising: determining which of the several operating modes is to be carried out, wherein the first operating mode is carried out when the exhaust gas temperature is above a threshold temperature, and the second operating mode is carried out when the exhaust gas temperature is below the threshold temperature.
[0006] The present disclosure further provides a computer program with program instructions which, when executed on a computer with at least one memory and at least one processor, cause the computer to perform the above procedures. The present disclosure further provides a computer-readable medium carrying such a computer program. The present disclosure further provides a computer programmed to perform the above procedures.
[0007] The present disclosure further provides a power engine system comprising: an exhaust aftertreatment module for receiving exhaust gas from an internal combustion engine, wherein the exhaust aftertreatment module has a reducing agent injector that is selectively actuated to inject a reducing agent fluid from an injector outlet into the exhaust aftertreatment module, and a control unit connected to the reducing agent injector and programmed to: store a first and a second set of injection parameters, inject reducing agent fluid from the reducing agent injector in one of several different operating modes, wherein the several different operating modes include: a first operating mode with injection of reducing agent fluid according to the first set of injection parameters to react with and substantially reduce one or more components of the exhaust gas in the exhaust aftertreatment module,and a second operating mode with injection of reducing agent fluid according to the second injection parameter set for expelling solid reducing agent deposits that have formed above the injector outlet, and determining which of the several operating modes is to be carried out, wherein the first operating mode is carried out when the exhaust gas temperature is above a threshold temperature, and the second operating mode is carried out when the exhaust gas temperature is below the threshold temperature.
[0008] The present disclosure further provides a method for controlling a reducing agent injector for injecting a reducing agent fluid from an injector outlet into an exhaust gas, wherein the method comprises: determining which of several different operating modes is to be carried out, wherein the several different operating modes comprise: a first operating mode with injection of reducing agent fluid according to a first set of injection parameters for reacting with and substantially reducing one or more components of the exhaust gas, and a second operating mode with injection of reducing agent fluid according to a second set of injection parameters for expelling solid reducing agent deposits that have formed above the injector outlet, wherein the execution of the first operating mode is determined when the exhaust gas temperature is above a threshold temperature, and the execution of the second operating mode is determined.when the exhaust gas temperature is below the threshold temperature.
[0009] Only by way of example are embodiments of a method for controlling a power machine system now described with reference to the attached drawings, as shown therein. Brief description of the drawings
[0010] Fig. Figure 1 is a schematic representation of a power machine system suitable for carrying out the method of the present disclosure,
[0011] Fig. Figure 2 is a schematic representation of an exhaust aftertreatment module of the engine system of Fig. 1,
[0012] Fig. Figure 3 is a schematic representation of a reducing agent injector of the exhaust aftertreatment module of Fig. 2 in a closed position, and
[0013] Fig. Figure 4 is a schematic representation of the reducing agent injector of Fig. 3 in an open position and with injection of reducing agent. Detailed description
[0014] The present disclosure relates generally to a method for controlling a power engine system with an aftertreatment module in which a reducing agent injector is positioned. The reducing agent injector can be controlled to inject a reducing agent fluid in such a way as to expel solid reducing agent deposits that have formed on or in the reducing agent injector. The reducing agent can be injected when the exhaust gas temperature is below a threshold temperature associated with the effective operation of the aftertreatment module. The reducing agent fluid can be injected periodically.
[0015] Fig. Figure 1 represents an exemplary embodiment of a power machine system 10which may be suitable for carrying out the method of the present disclosure. The power engine system 10 can a first line 11 to direct intake gas, such as outside air, to a turbocharger 12 exhibit. The turbocharger 12 can a turbocharger compressor 13 , the one with the first line 11 connected and arranged so that it is powered by a turbine 14 over a wave 15 is driven, exhibit. The power engine system 10 It can also include an additional (turbo)charger (supercharger) 16 for receiving intake gas from the turbocharger compressor 13 via a second line 17 exhibit a drive arrangement 18 The additional charger can be used for selective (optional) driving of the additional charger 16 It is intended to be a power machine. 19 can be used for the mechanical transfer of power to the next charger16 about the drive arrangement 18 the further loader is arranged. The power engine system 10 Furthermore, a third line can be used. 20 to direct the intake gas from the next turbocharger 16 to a cooler 21 exhibit the power machine system 10 Furthermore, a bypass arrangement may be used. 22 furthermore, they feature a turbocharger to selectively allow intake gas to enter the further turbocharger. 16 avoids.
[0016] The power machine 19 This can be an internal combustion engine, such as a compression-ignition or spark-ignition engine. A fuel, such as diesel, gasoline, or natural gas, can be selectively injected into the engine cylinders within the engine. 19The intake gases are used for combustion, driving the pistons and thus rotating a crankshaft, providing engine output torque and power. The byproduct of the combustion process is exhaust gas, which is routed from the engine cylinders along a fifth pipe. 23 of the power engine system 10 for example, it is routed via an exhaust manifold. The exhaust gas may contain undesirable gaseous emissions or pollutants, such as nitrogen oxides (NOx), particulate matter (e.g., soot), sulfur oxides, carbon monoxide, unburned hydrocarbons, and / or other organic components. As is known, the exhaust gas temperature can depend on the intake gas temperature and the engine load. The fifth pipe 23 exhaust gas from the engine 19 to the turbine 14 of the turbocharger 12 guide. The power engine system10 Furthermore, a sixth line can be added. 24 to direct exhaust gas from the turbine 14 to an exhaust aftertreatment module 25 exhibiting a turbine bypass arrangement. 26 It may be provided to selectively allow exhaust gas to enter the turbine. 14 avoids.
[0017] The exhaust aftertreatment module 25 It can capture the exhaust gas and treat it to remove pollutants before the exhaust gas is released into the atmosphere via a seventh pipe. 27 is directed. As detailed in the Fig. As shown in 2, the exhaust aftertreatment module 25 a system for selective catalytic reduction or an SCR system 28 exhibit and can have a diesel oxidation catalyst 29 exhibit. The diesel oxidation catalyst 29 can be used to collect exhaust gases from the sixth line 24 arranged and upstream of the SCR system 28be positioned. The SCR system 28 can an SCR line 30 exhibiting characteristics of the diesel oxidation catalyst 29 to an SCR catalyst arrangement 31 This leads to a reducing agent injector. 32 can in the SCR line 30 for the selective injection of a reducing agent fluid 33 into the SCR line 30 upstream of the SCR catalyst assembly 31 be positioned. The reducing agent fluid 33 It may contain aqueous urea, aqueous ammonia, or the like. In particular, the reducing agent fluid may contain aqueous ammonia. 33 It may be a diesel exhaust fluid (DEF) and the DEF may meet the ISO standard 22241 and contain urea from 31.8 wt% to 33.2 wt%.
[0018] The SCR catalyst arrangement 31 can create a mixer in the direction of the exhaust gas flow 34 , a catalyst substrate 35and another oxidation catalyst or AMOx 36 exhibit. The reducing agent injector 32 can the reducing agent fluid 33 preferably as a liquid selectively introduced into the exhaust gas stream to provide a dose (portion) of the reducing agent 33 for the SCR catalyst arrangement 31 inject. The high exhaust gas temperature can cause the reducing agent fluid to... 33 to cause it to evaporate, and the resulting combination of gases can act on the catalyst substrate 35 touch the reducing agent fluid 33 It can react with the NOx in the exhaust gas to reduce it to nitrogen and water, which comes from the engine system 10 via the seventh line 27 is directed. The catalyst substrate 35 may contain zeolites, vanadium, or the like.
[0019] The mixer 34This can ensure a uniform distribution and conversion of the reducing agent fluid. 33 upon entering the catalyst substrate 35 promote. During operation of the power engine system 10 Is it possible that there is too much reducing agent fluid? 33 is injected into the exhaust gas (i.e., an excess of urea compared to the amount required for proper NOx reduction). In the case where the reducing agent fluid 33 If urea is present, this situation is known as "ammonia slip" and a small amount of ammonia can pass through the catalyst substrate. 35 ammonia will be released into the atmosphere if not handled otherwise. To minimize ammonia leakage, the AMOx can be used. 36 downstream of the catalyst substrate 35 be positioned. The AMOx 36may have a substrate coated with a catalyst that oxidizes residual ammonia in the exhaust gas to form water and elemental nitrogen.
[0020] The power engine system 10 may furthermore include at least one sensor capable of measuring one or more parameters relating to one or more of the components of the power machine system 10 relating to, and is arranged to send signals relating to it to a controller. In particular, the power machine system can 10 have a temperature sensor that is connected to the control system for determining the exhaust gas temperature at the outlet of the engine 19 and / or in the exhaust aftertreatment module 25communicates (is in a communicating connection). The control unit can be capable of determining the exhaust gas temperature in any known way, for example, via engine maps or algorithms based on the intake gas temperature and the engine load. The control unit can also be equipped with one or more actuators to control the operation of the engine. 19 be in a communicating connection. In particular, the control unit can be used to control the turbocharger. 12 , furthermore, charger 16 , of the fuel injection volume flow to the engine 19 and the injection volume flow rate of the reducing agent fluid 33 through the reducing agent injector 32The control system must be operable (operable or controllable). It can be a computer and can be operated to store and execute one or more computer programs, and must have at least one memory, at least one processing unit, and at least one communication means. The control system can be an electronic control unit (ECU).
[0021] An example of a reducing agent injector 32 , which is suitable for such a power machine system 10 suitable is in the Fig. 3 and Fig. 4 shown. The reducing agent injector 32 can a case 37 for installation in the SCR system 28 , especially in the wall of the SCR line 30 , upstream of the SCR catalyst assembly 31 exhibit. Inside the casing 37 can a passage 38 from a reducing agent fluid inlet 39 to a nozzle 40 and an injector outlet41 lead. The reducing agent fluid inlet 39 can be in fluid connection with a reducing agent fluid supply system. The reducing agent fluid supply system can have a storage tank containing reducing agent fluid. 33 and a pump for selectively pumping the reducing agent fluid 33 from the storage tank via fluid lines to the reducing agent fluid inlet 39 exhibit. The pump can be controlled by the controller. A valve component. 42 can within the passage 38 be positioned and operated by an actuator 43 The actuator must be movable between an open position and a closed position. 43 It could be an electrically activated solenoid (electromagnet) or the like. The actuator 43It can be electronically connected to the control unit, allowing the control unit to manage its movement between the open and closed positions. The closed position is in Fig. 3 shown, in which the injector outlet 41 is closed and the reducing agent fluid 33 cannot flow through it. The open position is in Fig. 4 shown, in which the injector outlet 41 is open and the reducing agent fluid 33 can flow.
[0022] During operation of the power engine system 10 The control unit controls the injection of the reducing agent fluid. 33 to control the reduction of NOx by the SCR system 28 The SCR system 28 It can be more effective if the exhaust gas temperature is above a threshold temperature. The threshold temperature can be set by the exhaust aftertreatment module. 25be assigned. The threshold temperature can be the minimum temperature at which a chemical reaction occurs between the reducing agent fluid. 33 and the NOx reduction can take place reliably. The threshold temperature can be in the range of 80°C to 250°C, and particularly around 210°C. If the exhaust gas temperature is below the threshold, the injection of the reducing agent fluid may not be sufficient. 33 This can increase ammonia slip and lead to the formation of undesirable components, such as ammonium hydrogen sulfate, and impair the performance of the exhaust aftertreatment module. 25 deteriorate. Therefore, the SCR system could deteriorate. 28 It can only be operated if the exhaust gas temperature is above the threshold temperature.
[0023] The SCR system 28A preferred NOx conversion efficiency of at least 90% can be achieved when the exhaust gas temperature is above the threshold temperature. The NOx conversion efficiency can be further improved by positioning a first NOx sensor upstream of the SCR system. 28 and a second NOx sensor downstream of the SCR system 28 A NOx conversion efficiency of at least 90% indicates that the amount of NOx in the exhaust gas is reduced by at least 90% between the first and second NOx sensors of the SCR system. 28 was reduced.
[0024] The control system can operate the power machine system 10 in one of several operating modes (operating types or operating states). In particular, one or more computer programs may contain program instructions which, when executed in the control system, cause the control system to determine which of the several operating modes is to be implemented and the power machine system.10 The system can be operated in one of several operating modes. These modes can include a first, second, third, and fourth operating mode. If the exhaust gas temperature exceeds the threshold temperature, the controller can switch to the first operating mode to inject one or more portions of reducing agent fluid. 33 from the reducing agent injector 32 Perform with a first set of injection parameters. The first operating mode can use the reducing agent fluid. 33 for reacting with and significantly reducing one or more components of the exhaust gas in the exhaust aftertreatment module 25and in particular to reduce NOx in the exhaust gas. The first set of injection parameters can include a dosing duration and a dosing volume flow rate. The dosing duration can be the time the exhaust gas temperature is above the threshold temperature. The dosing volume flows can be based, for example, on the exhaust gas temperature, the amount of NOx in the exhaust gas, and the exhaust gas flow rate, and the dosing volume flows can be, for example, in the range of 40 ml / h to 8000 ml / h. If the exhaust gas temperature is below the threshold temperature of the SCR system 28 The control unit can then direct the reducing agent injector. 32 Do not operate in the first operating mode to avoid ammonia slippage.
[0025] In the fourth operating mode, the controller can operate the reducing agent injector. 32 and the reducing agent fluid supply system for removing residual reducing agent fluid 33Rinse (clean) it. In particular, the control unit can activate the pump of the reducing agent fluid supply system to extract the reducing agent injector. 32 (of the reducing agent fluid) 33 ) from the passage 38 This can control hardening and / or crystallization of the remaining reducing agent fluid. 33 prevent. The fourth operating mode can be used after the power unit is switched off. 19 be performed.
[0026] However, the reducing agent injector can 32 Do not use reducing agent fluid after performing the fourth operating mode. 33 be filled. Therefore, the third operating mode can be carried out, in which the reducing agent injector 32 by refilling (refilling) the passage 38 with reducing agent fluid 33 is prepared. After the reducing agent injector 32Once prepared, it can be supplied by the control system with a small preparation dose or portion of reducing agent fluid. 33 and / or air (if no reducing agent fluid) 33 next to the injector outlet 41 (after preparation) to check if the reducing agent injector 32 Normally, it can be actuated. In particular, a pressure sensor can be positioned in the reducing agent fluid supply system, and the controller can determine, by detecting a small change in the pressure output of the pressure sensor during the small preparation dose, that the preparation dose has been delivered and that the reducing agent injector is ready. 32 It works normally. The reducing agent injector 32 For example, it can inject the preparation dose in less than 50 ms. The reducing agent injector 32The control system can take this into account in such a way that it is in the prepared state after the small preparatory dose has been injected.
[0027] The third operating mode cannot cause the reducing agent injector to 32 immediately ready for injection of reducing agent fluid 33 Therefore, the control system may not be able to immediately execute the first operating mode as soon as the exhaust gas temperature reaches the threshold temperature. For example, the third operating mode 5The system requires between 120 and 120 seconds to reach the preparation state due to the length of the fluid lines in the reducing agent fluid supply system. The controller can therefore execute the third operating mode when at least one preparation parameter has been met. This at least one preparation parameter can be a predetermined preparation temperature, and the third operating mode can be executed when the exhaust gas temperature is below the threshold temperature but above the predetermined preparation temperature. The predetermined preparation temperature can be selected based on the time required to execute the third operating mode, referred to as the preparation time, and the threshold temperature.In particular, the predetermined preparation temperature can be selected such that the preparation time is the same as the time it takes for the exhaust gas temperature to rise from the predetermined preparation temperature to the metering temperature during a heating of the engine. 19 increases. For example, the predetermined preparation temperature can be in the range of approximately 80°C to approximately 250°C, or from approximately 80°C to approximately 120°C, and particularly 110°C. The control can adjust the reducing agent injector. 32 not for injecting reducing agent fluid 33 Control when the exhaust gas temperature is below the predetermined preparation temperature.
[0028] During injection in the first or third operating mode, the reducing agent fluid 33 back to the nozzle 40 after injection by eddy currents in the exhaust gases, which pass through the SCR line 30move, be guided. When the reducing agent injector 32 In the closed position, reducing agent fluid can 33 through the injector outlet 41 due to the high pressure of the reducing agent 33 in the passage 38 Leakage. A leakage of the reducing agent fluid. 33 can occur particularly in aged and worn reducing agent injectors 32 probable. The leaked reducing agent fluid 33 can lead to reducing agent fluid 33 at or in the nozzle 40 deposits. The amount that leaks out and deposits can increase if the reducing agent injector is used. 32 is not open for an extended period of time, such as after performing the third operating mode but before performing the first operating mode. The nozzle 40can typically have a relatively low surface temperature, such as around 200°C, so that the reducing agent fluid 33 at the nozzle 40 can condense. The liquid components of the reducing agent fluid 33 can subsequently evaporate and solid reducing agent deposits can form. 44 can at the nozzle 40 remain. Fig. 3 represents the reducing agent injector 32 in the closed position with the nozzle 40 formed solid reducing agent deposits 44 that show the injector outlet 41 Partially clog. Interruption of the reducing agent fluid flow. 33 from the reducing agent injector 32 can the conversion efficiency of the SCR system 28 reduce. If these solid reducing agent deposits 44 to build up further, you can access the injector outlet. 41Complete blockage. Partial or complete blockages can reduce the efficiency or effectiveness of flushing the reducing agent injector. 32 in the fourth operating mode, so that the remaining reducing agent fluid 33 within the reducing agent injector 32 can fix (fix) or crystallize.
[0029] As in Fig. As shown in section 4, the solid reducing agent deposits can be 44 from the blockage of the injector outlet 41 by opening the reducing agent injector 32 and injection of reducing agent fluid 33 into the SCR system 28 be removed. While the reducing agent fluid 33 from the injector outlet 41 As the flowing water is removed, the solid reducing agent deposits will be removed. 44 , which the injector outlet 41 partially clogged, away from the nozzle 40emitted. During low-load cycles, when the exhaust gas temperature is below the threshold temperature, meaning the first operating mode is rarely used, solid reducing agent deposits can form. 44 in and around the injector outlet 41 and the nozzle 40 form or thaw.
[0030] The controller can therefore select the second operating mode, in which the reducing agent fluid 33 from the reducing agent injector 32 for expelling and / or reducing the formation of solid reducing agent deposits 44 at the nozzle 40 and above the injector outlet 41 The injection process is carried out. In particular, the control unit can direct the reducing agent injector. 32 control while the exhaust gas temperature remains below the threshold temperature of the SCR system. 28 is and the reducing agent fluid 33It cannot be injected to reduce the amount of NOx in the exhaust gas. In particular, the second operating mode can be used when the SCR system is 28 It has a NOx conversion efficiency of less than 90%. The second operating mode can be carried out while the power unit is running. 19 is operated in low power machine load conditions and / or low load cycles when the first operating mode is not required.
[0031] The controller can then periodically execute the second operating mode and can execute the second operating mode after a predetermined time has elapsed since a previous execution of the first operating mode or a previous execution of the third operating mode. The second operating mode can therefore be used to provide a dose to the SCR system. 28This can be carried out if the exhaust gas temperature is between the predetermined preparation temperature and the threshold temperature. This can occur if the engine system 10 The engine was started and the exhaust gas temperature rose above the predetermined preparation temperature (i.e., so that the third operating mode was carried out), but since starting the engine system 10 This can occur if the system was operated with low engine loads or in a low-load cycle, so the exhaust gas temperature has not yet reached the threshold temperature. Alternatively, this can occur if the first operating mode was previously executed and the exhaust gas temperature subsequently falls below the threshold temperature for the predetermined duration.
[0032] The predetermined time duration can depend on the specific arrangement of the power machine system. 10depend on and is chosen in such a way as to prevent a sufficiently large amount of solid reducing agent deposits from forming. 44 forms, so that the injector outlet 41 is completely blocked. The predetermined duration can be at least 10 minutes, at least 20 minutes, or at least 30 minutes. The predetermined duration can range from 10 minutes to 10 hours. The predetermined duration can be approximately 60 minutes.
[0033] In the second operating mode, the controller can control the reducing agent injector. 32 for injecting reducing agent fluid 33 The system is operated or controlled according to a second set of injection parameters. This second set of injection parameters can include a predetermined injection volume flow rate and a predetermined metering duration. The predetermined injection volume flow rate can be selected such that a pressure is maintained behind the solid reducing agent deposits. 44to expel these from the injector outlet 41 The volume is increased as high as possible in a single dose. Therefore, the predetermined injection volume flow rate can be significantly larger than the metering quantity of the first operating mode. The predetermined metering duration can be significantly shorter than the metering duration of the first operating mode.
[0034] The predetermined dosing duration can range from 1 second to 120 seconds. Specifically, the predetermined dosing duration can be approximately 2 seconds. The predetermined injection volume flow rate can be a maximum injection volume flow rate of the reducing agent injector. 32 The predetermined injection flow rate can be between approximately 10 ml / h and approximately 12 l / h or between approximately 40 ml / h and approximately 8 l / h. In particular, the predetermined injection flow rate can be approximately 8 l / h.
[0035] In a particularly preferred embodiment, the predetermined time duration is approximately 60 minutes, the predetermined dosing time duration is approximately 2 seconds, and the predetermined injection volume flow rate is approximately 8 liters per hour. Accordingly, approximately 4.5 ml of the reducing agent fluid can be injected in a single dose. 33 into the SCR system 28 be injected.
[0036] The present disclosure applies to any suitable power engine system 10 featuring an exhaust aftertreatment module 25 with a reducing agent injector 32 applicable. In particular, the power machine system 10 an internal combustion engine 19 exhibit any suitable type. The power machine system 10 Only one or both can come from a turbocharger. 12 and another charger 16 exhibit. The control of the power engine system 10is programmed to perform each of the multiple operating modes. Commercial applicability
[0037] The method of the present disclosure can ensure that the solid reducing agent deposits 44 no blockages via the injector outlet 41 at times when reducing agent fluid 33 not into the SCR system 28 from the reducing agent injector 32 During the first operating mode, the reduced growth of solid reducing agent deposits occurs. 44 This prevents a reduction in the SCR system conversion efficiency. Furthermore, it can improve the efficiency of flushing or cleaning the reducing agent injector. 32 in the fourth operating mode and prevent the settling or crystallization of the remaining reducing agent fluid. 33 , which is inside the reduction injector 32 remaining can be prevented.
[0038] As a consequence, the process can lead to the formation of solid reducing agent deposits. 44 during cycles with low load on the power machine system 10 and if there is very little power or energy output from the power machine 19 required and exhaust gas temperatures are relatively low, prevent. The engine system 10 It can therefore be designed to operate effectively over medium and high load cycles without the need to reduce efficiency to prevent the formation of solid reducing agent deposits. 44 to impair cycles with low load. In particular, exhaust gas flow paths and exhaust gas temperature can, regardless of requirements, impair the formation of solid reducing agent deposits. 44 to prevent, to be controlled.
[0039] The power engine system 10The methods for operating the present disclosure may therefore be particularly suitable for working machines that must be operated with maximum efficiency in medium- and high-load cycles, in which the first operating mode can be carried out, but which can also be operated for extended periods in low-load cycles, in which the second and third operating modes can be carried out. Suitable working machines may include backhoe loaders, excavators, wheel loaders, bulldozers, and the like, which may have working tools such as backhoe buckets and excavator shovels. The working machines can be operated in medium- and high-load cycles when they are moving at a relatively high speed and / or during operation of the working tools.The working machines can be operated in low-load cycles when the working tools are not in use, the working machines are moving at low speeds and / or the power machine system is not in use. 10 the work machines are idling. QUOTES INCLUDED IN THE DESCRIPTION
[0040] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature
[0041] ISO standard 22241
[0017]
Claims
[1] Method for controlling a power-machine system ( 10 ), wherein the power machine system ( 10 ) shows: an exhaust aftertreatment module ( 25 ) for capturing the exhaust gas from an internal combustion engine ( 19 ), wherein the exhaust aftertreatment module ( 25 ) a reducing agent injector ( 32 ) has a nozzle for injecting a reducing agent fluid ( 33 ) from an injector outlet ( 41 ) into the exhaust aftertreatment module ( 25 ) is selectively operable, and a control system designed to inject a reducing agent fluid from the reducing agent injector ( 32 ) to control in one of several different operating modes, the multiple operating modes being: a first operating mode with injection of reducing agent fluid ( 33) according to a first injection parameter set to react with and substantially reduce one or more components of the exhaust gas in the exhaust aftertreatment module ( 25 ), and a second operating mode with injection of reducing agent fluid ( 33 ) according to a second injection parameter set for expelling solid reducing agent deposits ( 44 ), which are located above the injector outlet ( 41 have formed the procedure exhibits: Determine which of the several operating modes is to be carried out, wherein the first operating mode is carried out when the exhaust gas temperature is above a threshold temperature, and the second operating mode is carried out when the exhaust gas temperature is below the threshold temperature. [2] Method according to claim 1, wherein a metering volume flow rate of the first injection parameter set is greater than a predetermined injection volume flow rate of the second injection parameter set. [3] Method according to claim 1 or claim 2, wherein the exhaust aftertreatment module ( 25 ) a system ( 28 ) for selective catalytic reduction with a catalyst arrangement ( 31 ) for selective catalytic reduction downstream of the reducing agent injector ( 32 ) exhibits. [4] Method according to claim 3, wherein the system ( 28 ) for selective catalytic reduction in the first operating mode exhibits a NOx conversion efficiency of at least 90%, and the system ( 28 ) exhibits a NOx conversion efficiency of less than 90% for selective catalytic reduction in the second operating mode. [5] Method according to any one of the preceding claims, wherein the several different operating modes also include a third operating mode with filling of the reducing agent injector ( 32 ) with reducing agent fluid ( 33 ), so that the reducing agent injector ( 32 ) in a prepared state ready for injection of reducing agent fluid ( 33 ) is, exhibits, The third operating mode is carried out when at least one preparation parameter has been met and the exhaust gas temperature is below the threshold temperature, and The first operating mode or the second operating mode is performed after the third operating mode has been performed. [6] The method of claim 5, wherein the third operating mode further comprises: Operating the reducing agent injector ( 32 ) after this is used to inject a preparatory dose of reducing agent fluid ( 33 ) was filled, Detecting a pressure drop in the reducing agent injector ( 32 ) during the pre-dose, and Refilling the reducing agent injector ( 32 ) with reducing agent fluid ( 33 ), so that the reducing agent injector ( 32 ) is in the preparation stage. [7] Method according to claim 5 or claim 6, further comprising performing the second operating mode after a predetermined period of time following the performance of the third operating mode. [8] Method according to one of the preceding claims, comprising performing the second operating mode after a predetermined period of time following the performance of the first operating mode. [9] Method according to claim 7 or claim 8, wherein the predetermined time duration is at least 10 minutes, at least 20 minutes or at least 30 minutes, or the predetermined time duration is in the range of approximately 10 minutes to approximately 1 hour, or the predetermined time duration is approximately 60 minutes. [10] Method according to one of the preceding claims, wherein the second injection parameter set comprises a predetermined injection volume flow rate and a predetermined metering time duration, each selected such that a pressure behind solid reducing agent deposits ( 44 ), which are located above the injector outlet ( 41 ) have formed, to expel these from the injector outlet ( 41 ), is raised high enough. [11] Method according to claim 10, wherein the predetermined injection volume flow rate is the maximum injection volume flow rate of the reducing agent injector ( 32 ) is. [12] Method according to claim 10 or claim 11, wherein the predetermined injection volume flow rate is between approximately 10 ml / h and approximately 12 l / h or between approximately 40 ml / h and approximately 8 l / h. [13] Method according to any one of claims 10 to 12, wherein the predetermined dosing time is in a range from approximately 1 second to approximately 120 seconds. [14] Computer program comprising program instructions which, when executed on a computer with at least one memory and at least one processor, cause the computer to execute the method according to any of the preceding claims. [15] Power engine system ( 10 ) with: an exhaust aftertreatment module ( 25 ) for collecting exhaust gas from an internal combustion engine ( 19 ), wherein the exhaust aftertreatment module ( 25 ) a reducing agent injector ( 32 ) has a nozzle for injecting a reducing agent fluid (33 ) from an injector outlet ( 41 ) into the exhaust aftertreatment module ( 25 ) is selectively operable, and a control system that, in conjunction with the reducing agent injector ( 32 ) is set up and programmed for: Saving a first injection parameter set and a second injection parameter set, Injection of reducing agent fluid ( 33 ) from the reducing agent injector ( 32 ) in one of several different operating modes, the several different operating modes being: a first operating mode with injection of reducing agent fluid ( 33 ) according to the first injection parameter set to react with and substantially reduce one or more components of the exhaust gas in the exhaust aftertreatment module ( 25 ), and a second operating mode with injection of reducing agent fluid ( 33) according to the second injection parameter set for expelling solid reducing agent deposits ( 44 ), which are located above the injector outlet ( 41 have formed, and Determine which of the several operating modes is to be carried out, wherein the first operating mode is carried out when the exhaust gas temperature is above a threshold temperature, and the second operating mode is carried out when the exhaust gas temperature is below the threshold temperature.