Method for determining the amount of fluid to be introduced into an exhaust system by means of a fluid supply system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-10
- Publication Date
- 2026-08-11
AI Technical Summary
[0010]However, as has already been shown, the required amount can sometimes vary very dynamically, for example, depending on driving conditions. This can also result in the maximum amount of fluid that can be introduced into the exhaust system via the fluid supply system (hereinafter referred to as the maximum amount) being less than the required amount. This can lead to insufficient exhaust gas treatment.
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Figure CN122543828A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for determining the amount of fluid to be introduced into an exhaust gas system by means of a fluid supply system, a method for operating a fluid supply system, and a computing unit and computer program for performing said method. Background Technology
[0002] In the aftertreatment of exhaust gases in motor vehicles, especially for the reduction of nitrogen oxides (NOx), the so-called SCR (Selective Catalytic Reduction) method can be used. Here, an aqueous urea solution (HWL) is introduced into the exhaust gas as a reducing agent. For this purpose, a dispensing module or valve including nozzles can be used as a component of the fluid supply system to inject or introduce the aqueous urea solution into the exhaust gas stream. Upstream of the SCR catalyst, the aqueous urea solution reacts to generate ammonia, which then combines with nitrogen oxides at the SCR catalyst, thereby producing water and nitrogen. Summary of the Invention
[0003] According to the present invention, a method for determining the amount of fluid and a method for operating a fluid supply system, characterized by the independent claims, are proposed, along with a computing unit and a computer program for performing said methods. Advantageous designs are the subject of the dependent claims and the following description.
[0004] The present invention relates to a fluid supply system used in exhaust aftertreatment in a vehicle having an internal combustion engine, its operation, and the determination of the amount of fluid to be introduced by means of such a fluid supply system.
[0005] The fluid supply system has a delivery unit, for example in the form of a pump or including a pump, which is connected to a fluid storage tank via a delivery line and has a pressure line. The delivery unit is connected to a dispensing module via the pressure line, the dispensing module being configured to discharge fluid. Such a fluid supply system is used in exhaust aftertreatment systems to introduce fluid, such as a reducing agent or reducing agent solution, into the exhaust system. As an additional option, a return device can be connected to the fluid storage tank, through which excess fluid can be returned. A baffle or throttle in the return device can control the return flow. In this context, particularly applicable to so-called commercial vehicles (especially heavy-duty commercial vehicles), a dual-pump configuration can also be used for delivery and thus as a delivery unit, with one pump responsible for delivery and one pump responsible for return. The latter is particularly suitable for passenger cars or, where necessary, light-duty commercial vehicles.
[0006] One or more catalysts, particularly SCR catalysts, are installed in the exhaust gas system. Specifically, an aqueous urea solution reacts upstream of the SCR catalyst to generate ammonia, which then combines with nitrogen oxides at the SCR catalyst to produce water and nitrogen.
[0007] In the case of exhaust aftertreatment systems, the fluid supply system is typically designed such that it dispenses the necessary amount of fluid, or reducing agent, into the exhaust gas, calculated based on the amount of nitrogen oxides emitted at the motor outlet. Adherence to this requirement is crucial to ensure that no harmful emissions are emitted from the vehicle's exhaust pipe. This necessary amount is typically determined within the framework of a so-called dispensing strategy, and will hereinafter referred to as the required amount.
[0008] This allocation strategy is typically implemented within the framework of controlling the internal combustion engine, and the required quantities are therefore determined, particularly in the motor controller (ECU), or the software running there.
[0009] Typically, the fluid supply system, particularly one or more dispensing modules and, if necessary, the delivery unit, is controlled through an exhaust gas aftertreatment controller (DCU - Dosing Control Unit), or the software running there. The exhaust gas aftertreatment controller is then in communication with the motor controller. However, it is also conceivable that the software for controlling the fluid supply system runs on the motor controller.
[0010] However, as has already been shown, the required amount can sometimes vary very dynamically, for example, depending on driving conditions. This can also result in the maximum amount of fluid that can be introduced into the exhaust system via the fluid supply system (hereinafter referred to as the maximum amount) being less than the required amount. This can lead to insufficient exhaust gas treatment.
[0011] In this context, information has been proposed regarding the maximum amount of fluid that can be introduced into the exhaust gas system via a fluid supply system. Specifically, this maximum amount can be determined, or has already been determined, using the fluid supply system or a portion thereof.
[0012] The maximum quantity can depend on various parameters. These parameters include, in particular, the drift of one or more of the multiple dispensing modules, the pressure of the fluid in the fluid supply system, the maximum operating time of one or more of the multiple dispensing modules, the temperature of one or more of the multiple dispensing modules, the exhaust back pressure in the exhaust system, and the maximum operating frequency of the delivery unit of the fluid supply system. The maximum quantity can therefore be determined based on at least one of these parameters, and is therefore very real-time. Specific values of these parameters can be determined, for example, using appropriate sensors or control data, based on which the maximum quantity can be determined.
[0013] Then, taking into account the maximum amount, the required amount of fluid to be introduced into the exhaust gas system via the fluid supply system is determined. This can include different steps, specifically limiting the desired amount of fluid to the maximum amount, redistributing at least a portion of the desired amount of fluid among multiple dispensing modules, and pre-saving a portion of the desired amount of fluid for the required amount to be determined for a later introduction process. In particular, the last two steps are achieved while still performing exhaust gas reduction as desired or at least as well as possible.
[0014] In addition, the required quantity is determined as is usually done, for example, based on the rationing strategy or the current operating conditions of the internal combustion engine.
[0015] This information is then provided regarding the required quantity, more specifically, to control the fluid supply system for introduction. The fluid supply system can then be controlled accordingly to introduce the required quantity of fluid.
[0016] Subsequently, the introduced quantity, together with (and then the new) maximum quantity, can be determined and provided as the introduced quantity. The time between the operation of the two dispensing valves depends in particular on the dispensing requirements specified by the dispensing strategy.
[0017] Here, the fluid supply system is therefore controlled primarily by the operating frequency of the dispensing module. The pump, or delivery unit, simply needs to respond and maintain a stable pressure. Ideally, or normally, this balances out; otherwise, the dispensing module would remain open for too long (dispensing demands would be too high), and the pump would not be able to respond quickly enough, resulting in a sudden pressure drop. However, a pressure greater than 4.5 bar should always be maintained appropriately to achieve a spray pattern and prevent leaks.
[0018] In terms of system technology, the frequency can typically be between the minimum opening and 1 second (1000 ms) remaining (wherein referred to as leakage), the minimum opening being, for example, a 10 ms operating time, in which case the needle valve 100% springs back and is immediately pressed back by the spring. The valve opening time is typically between 10 ms for the minimum amount and 100 ms for a larger amount. The needle valve then briefly closes and immediately opens again.
[0019] However, there is absolutely no correlation between the valve opening time and the motor, or internal combustion engine, and the exhaust aftertreatment system. It depends purely on the motor's emissions and the untreated emissions that need to be reduced. This is the task of the rationing strategy.
[0020] Depending on where and how the software for the fluid supply system executes, the aforementioned steps can be implemented on one or different computing units. When the software for the fluid supply system runs on a separate DCU, while the dispensing strategy runs on the ECU, the maximum quantity is determined in the DCU and obtained and used in the ECU. The required quantity is then determined in the ECU, obtained in the DCU, and used to control the fluid supply system. When the software for the fluid supply system runs on the ECU, as with the dispensing strategy, all the mentioned steps are implemented on the ECU; however, data exchange can still be achieved between different software modules where necessary.
[0021] In one implementation, in addition to information about the maximum quantity, information about the amount of fluid introduced into the exhaust system via the fluid supply system is also provided, received, or output. If a separate calculation unit exists, the introduced quantity can also be determined in the DCU. The introduced quantity can also be taken into account when determining (and subsequently the next) required quantity.
[0022] The maximum quantity can be determined jointly for multiple distribution modules and / or individually for each of the multiple distribution modules. This allows for a more precise adaptation or determination of the required quantity across multiple distribution modules. Specifically, and generally, the required quantity can then be determined jointly for multiple distribution modules and / or individually for each of the multiple distribution modules. In the latter case, the required quantity includes, for example, a portion of the required quantity for each distribution module. This applies correspondingly to the maximum quantity.
[0023] The computing unit according to the invention, such as a controller for a motor vehicle, especially an exhaust aftertreatment controller or a motor controller, is configured, particularly in terms of programming technology, to execute the method according to the invention.
[0024] It is also advantageous to implement the method according to the invention as a computer program or a computer program product having program code for performing all the method steps, because this results in particularly low cost, especially when the controller used for implementation is also used for other tasks and therefore already exists. Finally, a machine-readable storage medium is provided having a computer program stored thereon as described above. Suitable storage media or data carriers for providing the computer program are, in particular, magnetic, optical, and electrical memories, such as hard disks, flash memory, EEPROM, DVDs, etc. Downloading the program via a computer network (Internet, intranet, etc.) is also feasible. Such downloading can be performed via wired or cable connections or wirelessly (e.g., via WLAN networks, 3G, 4G, 5G, or 6G connections, etc.).
[0025] Further advantages and design schemes of the present invention can be obtained from the specification and drawings.
[0026] The present invention is schematically illustrated in the accompanying drawings according to embodiments and will now be described with reference to the drawings. Attached Figure Description
[0027] Figure 1 A fluid supply system for exhaust gas aftertreatment in a vehicle is schematically illustrated, wherein the method according to the invention can be performed.
[0028] Figure 2 The flowchart of one implementation method is illustrated schematically. Detailed Implementation
[0029] exist Figure 1The diagram schematically illustrates a fluid supply system 100 for a vehicle, particularly in the form of an SCR supply system, configured for exhaust aftertreatment and capable of performing the method according to the invention. The SCR supply system 100 has a delivery unit 130 configured as a pump, equipped with a filter 132. The pump 130 is configured to deliver fluid, or reducing agent 121 (e.g., an aqueous urea solution), from a fluid reservoir 120 via delivery lines 126 and pressure lines 122 to a dispensing module or dispensing valve 140. The fluid 121 is then introduced or dispensed into the exhaust system 170 or exhaust gas system of the internal combustion engine 192 via the dispensing valve 140.
[0030] In addition, a pressure sensor 142 (which can also be integrated into the pump) is provided, configured to measure at least the pressure in the pressure line 132 and therefore in the fluid. A computing unit 150, for example in the form of an exhaust gas aftertreatment controller, is connected to the pressure sensor 142 and obtains information about the pressure in the pressure line 122. Furthermore, the computing unit 150 is connected to the pump 130 and the dispensing valve 140 to control or operate the SCR supply system 100.
[0031] Furthermore, the SCR supply system 100 includes, for example, a return line 160 through which fluid can be returned to the fluid storage tank 120. A baffle or throttle valve 161, for example, is arranged in the return line 160 to provide localized flow resistance. However, it should be noted that such a return device can be omitted in pumps with actively controlled valves. Additionally, a return pump not shown here, as well as other sensors as mentioned at the beginning, can be installed.
[0032] The calculation unit 150 is configured to receive and use relevant data, particularly from the temperature sensor 177 in the exhaust gas system, which in particular can detect the temperature of the catalyst 174, in order to operate the SCR supply system 100 and, in particular, control the pump 130 and the dispensing valve 140, so as to also supply the urea aqueous solution 121 (fluid) in front of the catalyst, or SCR catalyst 174, into the exhaust gas system 170. It should be noted that the pressure can also be determined in other ways by means of sensors, for example, based on pump operating data.
[0033] Although only one dispensing module 140 is shown here, the SCR supply system can also have multiple dispensing modules, all of which can then supply fluid accordingly. Similarly, multiple catalysts can be configured.
[0034] Furthermore, a computing unit 190 configured as a motor controller for the internal combustion engine 192 is shown as an example. During the operation or control of the internal combustion engine, a dispensing strategy can be implemented on the motor controller 190, while the exhaust aftertreatment controller 150 is used to operate or control the SCR supply system 100.
[0035] The motor controller 190 and the exhaust aftertreatment controller 150 are connected via a CAN bus, for example. However, as already mentioned, it is also conceivable that the software for operating the SCR supply system 100 is integrated into the motor controller, in which case a separate exhaust aftertreatment controller would not be necessary.
[0036] exist Figure 2 The diagram schematically illustrates the flow of a method employing one implementation. This is based on the case of having two separate computing units (as also...). Figure 1 As shown in the diagram, this is achieved through steps executed by the corresponding computing unit. Specifically, an exhaust gas aftertreatment controller 150 and a motor controller 190 are shown here.
[0037] In step 200, the amount of fluid to be introduced into the exhaust gas system via the fluid supply system is determined in the exhaust gas aftertreatment controller 150. This can be achieved, for example, based on operating parameters such as pressure and introduction duration. Information 202 regarding the introduction amount is transmitted to the motor controller 190 in step 204, and is received therein in step 206.
[0038] In step 210, the maximum amount of fluid that can be introduced into the exhaust system via the fluid supply system is determined in the exhaust aftertreatment controller 150. This can be achieved, for example, based on the parameters already mentioned (the drift or pressure of one or more supply modules). Information 212 regarding the maximum amount is transmitted to the motor controller 190 in step 214, and is received there in step 216.
[0039] Information 202 and 212 can be transmitted together in a message or sequentially to each other.
[0040] In step 220, the required amount of fluid to be introduced into the exhaust system via the fluid supply system is determined in the motor controller 150. This is achieved, for example, based on the current operation of the internal combustion engine and taking into account the maximum amount. Information 222 regarding the required amount is transmitted to the exhaust aftertreatment controller 150 in step 224, and is received therein in step 226.
[0041] In step 230, the exhaust gas aftertreatment controller 150 then controls the SCR supply system to introduce fluid into the exhaust gas system in the required amount. When, for example, the required amount is allocated to multiple dispensing modules, this can include corresponding control of the multiple dispensing modules.
[0042] The process can then be restarted in step 200 by determining the amount of material introduced in the previously described introduction process.
Claims
1. A method for determining the amount of fluid to be introduced into an exhaust gas system via a fluid supply system, wherein, The fluid supply system (100) is configured for exhaust gas aftertreatment and has one or more dispensing modules (140) configured to introduce fluid (121) into the exhaust gas system of the vehicle's internal combustion engine (192), the method comprising: Provide or receive (216) information (212) about the maximum amount of fluid that can be introduced into the exhaust gas system by means of the fluid supply system. Taking into account the maximum quantity, determine (220) the required amount of fluid to be introduced into the exhaust gas system by means of the fluid supply system; and Provide or output (224) information (222) about the required amount for controlling the fluid supply system to introduce fluid.
2. A method for operating a fluid supply system (100), the fluid supply system being configured for exhaust gas aftertreatment and having one or more dispensing modules (140) configured to introduce fluid (121) into the exhaust gas system of an internal combustion engine (192) of a vehicle, the method comprising: Determine (210) the maximum amount of fluid that can be introduced into the exhaust gas system by means of the fluid supply system; Provide or output (214) information (212) about the maximum quantity; Provide or receive (226) information (222) regarding the required amount of fluid to be introduced into the exhaust gas system by means of the fluid supply system, wherein the required amount has been determined taking into account the maximum amount; and The fluid supply system is controlled based on the required amount to introduce fluid.
3. A method for operating a fluid supply system (100), the fluid supply system being configured for exhaust aftertreatment and having one or more dispensing modules (140) configured to introduce fluid (121) into the exhaust system of an internal combustion engine (192) of a vehicle, the method comprising: Determine (210) the maximum amount of fluid that can be introduced into the exhaust gas system by means of the fluid supply system; Taking into account the maximum amount, determine (220) the required amount of fluid to be introduced into the exhaust gas system by means of the fluid supply system; Provide information about the required quantity (222); and The fluid supply system is manipulated (230) based on the required amount to introduce fluid.
4. The method according to any of the preceding claims, wherein, Determining the required quantity, taking into account the maximum quantity, includes at least one of the following steps: - Limit the desired amount of fluid to the maximum amount; - To redistribute at least a portion of the desired amount of fluid among multiple dispensing modules; and - Reserve a portion of the desired fluid volume in advance for use in the later introduction process where the required amount is yet to be determined.
5. The method according to any one of the preceding claims, wherein, In addition to information about the maximum amount, information is provided, received, or output regarding the amount of fluid introduced into the exhaust gas system by means of the fluid supply system.
6. The method according to any one of the preceding claims, wherein, The maximum quantity is determined or has been determined based on at least one of the following parameters: - Drift of one or more of the multiple rationing modules. - The pressure of the fluid in the fluid supply system, - The maximum control time for one or more of the multiple supply modules. - The temperature of one or more of the multiple supply modules; - The back pressure of the exhaust gas in the exhaust gas system - The maximum operating frequency of the delivery unit of the fluid supply system.
7. The method according to any one of the preceding claims, wherein, The maximum quantity is determined or has been determined jointly for multiple distribution modules and / or individually for each of the multiple distribution modules.
8. The method of any of the preceding claims, wherein, The fluid supply system further includes a delivery unit (130), a delivery pipeline (126), and a pressure pipeline (122). The delivery unit (110) is connected to the fluid storage tank (120) via the delivery pipeline, and the delivery unit (130) is connected to the one or more distribution modules (140) via the pressure pipeline. In the exhaust gas system (170), one or more catalysts are provided downstream.
9. The method of any of the preceding claims, wherein, The fluid supply system (100) has an SCR supply system in which an aqueous urea solution is used as the fluid.
10. A computing unit (150, 190) configured to execute all method steps of the method according to any one of the preceding claims.
11. A computer program, when implemented on the computing unit (150), causes the computing unit (150) to perform all the method steps of the method according to any one of claims 1 to 9.
12. A machine-readable storage medium having a computer program stored thereon according to claim 11.