ELECTRONIC PRESSURE RELIEF IN PUMPS

Abstract

Post-treatment system (100), comprising: a selective catalytic reduction system (150) comprising a catalyst (154) for reducing components of an exhaust gas; a reducing agent storage tank (110); a reducing agent supply assembly (120, 220) which is fluidically coupled to the reducing agent storage tank (110) and the selective catalytic reduction system (150), wherein the reducing agent supply assembly (120, 220) comprises a pump (122, 222) and a metering valve (126) which is fluidically coupled to the pump (122, 222); a sensor circuit (130, 230) configured to detect a rotor position and acceleration, from which a torque generated by the pump (122, 222) can be determined; and a control unit (170, 270) that is communicatively coupled to the reducing agent supply component (120, 220) and the sensor circuit (130, 230), wherein the control unit (170, 270) is configured such that it: the pump (122, 222) is initialized to pressurize a reducing agent in the pump (122, 222), the metering valve (126) opens and thereby supplies the reducing agent to the selective catalytic reduction system (150), the torque generated by the pump (122, 222) is determined based on the rotor position and acceleration detected by the sensor circuit (130, 230), whereby the torque indicates an operating pressure of the pump (122, 222), and as a reaction to the torque exceeding a threshold, the pump (122, 222) stops.

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to aftertreatment systems for use with internal combustion engines (IC engines). BACKGROUND

[0002] Exhaust aftertreatment systems are used to capture and treat exhaust gases produced by internal combustion engines. Generally, exhaust aftertreatment systems comprise any number of several different components to reduce the proportion of harmful exhaust emissions. For example, certain exhaust aftertreatment systems for diesel-powered internal combustion engines include a selective catalytic reduction (SCR) system to convert NOx (NO and NO2 in small proportions) into harmless nitrogen gas (N2) and water vapor (H2O) in the presence of ammonia (NH3). In such aftertreatment systems, an exhaust reducing agent (e.g., a diesel exhaust fluid such as urea) is injected into the SCR system to provide an ammonia source and mixed with the exhaust gas to partially reduce the NOx gases.The byproducts of exhaust gas reduction are then fluidically directed to the catalyst present in the SCR system to essentially break down all NOx gases into relatively harmless byproducts that are expelled from the aftertreatment system.

[0003] An exhaust gas reducing agent is typically fed into the SCR system as an ammonia source to facilitate the reduction of exhaust gas components such as NOx gases (e.g., from diesel exhaust). Pumps are commonly used to supply the reducing agent to the SCR system. Generally, such pumps include mechanical pressure relief valves that are passively activated to relieve pressure and prevent excessive pressure buildup in the pump. Pressure relief valves frequently malfunction or fail and require replacement, significantly increasing the maintenance costs of these systems.

[0004] EP 2 524 140 B1 relates to a method for controlling a motor-driven pump for an SCR system, wherein the pump provides a pressure, is subjected to a hydraulic torque related to this pressure and also to a resistance torque, and is driven by an electric motor which comprises current-supplied windings and develops a torque related to this current, wherein, for controlling the pump, a means for measuring the current in the windings of the motor and a controller of the total current consumed by the motor are used. SUMMARY

[0005] The embodiments described herein generally relate to systems and methods for preventing excessive pressure build-up in pumps, and in particular to using a value of the pump's electrical operating parameter as a proxy for the pump's operating pressure and to stopping the pump when the value of the electrical operating parameter exceeds an operating threshold. The embodiments of the systems and methods described herein are configured to prevent the pump's operating pressure from exceeding the operating threshold, thus eliminating the need for a pressure relief valve in the pump.

[0006] A first set of embodiments comprises an aftertreatment system, specifically an SCR system, which includes a catalyst for reducing the components of an exhaust gas. The aftertreatment system also includes a reducing agent storage tank. A reducing agent supply component is fluidically connected to the reducing agent storage tank and the SCR system. The reducing agent supply component includes a pump and a metering valve that is fluidically coupled to the pump. A control unit is communicatively connected to the reducing agent supply component. The control unit is configured to initialize the pump by pressurizing a reducing agent within the pump. The control unit opens the metering valve, thereby supplying the reducing agent to the SCR system. The control unit determines a value for the pump's electrical operating parameter. This electrical operating parameter indicates the pump's operating pressure.The control unit determines whether the value of the electrical operating parameter exceeds a predefined operating threshold. In response to the value of the electrical operating parameter exceeding the operating threshold, the control unit stops the pump.

[0007] A second set of embodiments comprises a reducing agent supply component, a pump, and a metering valve fluidically coupled to the pump. A sensor circuit is configured to detect one or more electrical parameters of the pump. A control unit is communicatively coupled to the pump and the sensor circuit. The control unit is configured to initialize the pump by pressurizing a reducing agent within it. The control unit opens the metering valve, thereby dispensing a reducing agent. The control unit uses the sensor circuit to determine a value of the pump's electrical operating parameter. This value indicates the pump's operating pressure. The control unit determines whether the value of the electrical operating parameter exceeds a predefined operating threshold.In response to the value of the electrical operating parameter exceeding the operating threshold, the control unit stops the pump.

[0008] A third set of embodiments comprises a method for operating a reducing agent supply component, which includes a pump and a metering valve, designed to be fluidically coupled to a post-treatment system. The pump is initialized to pressurize a reducing agent within the pump to an operating pressure. The metering valve opens, thus supplying the reducing agent to the post-treatment system. The system then determines whether a value of the electrical operating parameter exceeds a predetermined operating threshold of the pump. The value of the electrical operating parameter indicates the pump's operating pressure. In response to the electrical operating parameter exceeding the operating threshold, the pump is stopped.

[0009] A fourth set of embodiments comprises a control circuit, a control unit configured to be communicatively coupled to a reducing agent supply component, which includes a pump and a metering valve fluidically coupled to the pump and a sensor circuit. The control unit includes a torque-adjusting circuit, a metering-control circuit, and a pressure-setting circuit. The torque-adjusting circuit is configured to initialize the pump to pressurize a reducing agent within the pump. The metering-control circuit is configured to open the metering valve, thereby dispensing a reducing agent. The pressure-setting circuit is configured to determine an operating pressure of the pump from a value of the pump's electrical operating parameter provided by the sensor circuit.The electrical operating parameter indicates the pump's operating pressure. The pressure-determining circuit is also configured to detect whether the value of the electrical operating parameter exceeds a predefined operating threshold. The torque-adjusting circuit is configured to stop the pump in response to the electrical operating parameter exceeding the operating threshold.

[0010] It should be clarified that all combinations of the foregoing concepts and further concepts discussed in more detail below (provided that these concepts are not mutually incompatible) are intended to be part of the subject matter disclosed herein according to the invention. In particular, all combinations of the claimed subject matter listed at the end of this disclosure are intended to be part of the subject matter disclosed herein according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing and further features of the present disclosure will become clearer with reference to the following description and the attached claims, which should be read in conjunction with the accompanying drawings. Provided that these drawings merely represent several embodiments according to the disclosure and are therefore not to be regarded as limiting its scope of protection, the disclosure is described in more detail and with reference to the accompanying drawings. Fig. Figure 1 is a schematic representation of a post-treatment system according to one embodiment. Fig. 2 is a schematic block diagram of another embodiment of a control circuit, to which the control unit of Fig. 1 can belong. Fig. 3 is a schematic block diagram of a further embodiment of a sensor circuit of a reducing agent feed component, which is used in the post-treatment system of Fig. 1 is included. Fig. Figure 4 is a schematic flowchart of a method to prevent the operating pressure of a pump enclosed in a reducing agent feed component of a post-treatment system from exceeding a pressure threshold of the pump. Fig. Figures 5-16 are various diagrams showing the performance (pump speed or pressure versus time) of a first pump (Pump 1) providing pressure relief using a pressure relief valve, and a second pump (Pump 2) operated according to the systems and methods described herein. Fig. 17 and Fig. Figure 18 shows diagrams of the operating pressure versus the current consumed by pumps operating at 14 volts or 27 volts, respectively, for a new pump, by a pump operating for more than 20,000 hours, and by a pump operating at a maximum dosing rate for more than 20,000 hours. Fig. 19 is a schematic block diagram of an embodiment of a computer device used in the post-treatment system of Fig. 1 may be included as a control unit.

[0012] Throughout the following detailed description, reference is made to the accompanying drawings. In the drawings, similar symbols normally denote similar components, unless the context indicates otherwise. The illustrative descriptions presented in the detailed description, drawings, and claims are not intended to be restrictive. Other embodiments may be used, and other modifications may be made without departing from the fundamental concept or scope of protection of the subject matter presented here. It is understood that the aspects of this disclosure, generally described herein and illustrated in the figures, may be arranged, substituted, combined, and implemented in a wide variety of different configurations, all of which are expressly suggested and form part of this disclosure. DETAILED DESCRIPTION OF VARIOUS EXECUTION FORMS

[0013] The embodiments described herein generally relate to systems and methods for preventing excessive pressure build-up in pumps, and in particular to using a value of the pump's electrical operating parameter as a proxy for the pump's operating pressure and to stopping the pump when the value of the electrical operating parameter exceeds an operating threshold. The embodiments of the systems and methods described herein are configured to prevent the pump's operating pressure from exceeding the operating threshold, thus eliminating the need for a pressure relief valve in the pump.

[0014] Reducing agent feed components are used to inject or otherwise introduce a reducing agent into a post-treatment component, such as an SCR system, that is enclosed within the post-treatment system. Generally, reducing agent feed components include a pump designed to pressurize the reducing agent to a predetermined operating pressure or other pressure range for delivery into the post-treatment system. To prevent the pump from exceeding the predetermined operating pressure or over-pressurizing the reducing agent, the pump or reducing agent feed component generally includes a mechanical pressure relief valve designed to provide pressure relief.If the pressure exceeds a certain pressure threshold of the pump, the pressure relief valve opens, allowing at least some of the reducing agent to be expelled from the pump and returned, for example, to a reducing agent storage tank. These mechanical pressure relief valves are prone to blockages and malfunctions, which can occur due to dust, contaminants, or the solidification of reducing agent within the valve. This can significantly increase the pump's maintenance frequency and costs.

[0015] Many embodiments of the systems and methods described herein for preventing the pressure of a pump enclosed in a reducing agent feeder from exceeding a pressure threshold without the use of a pressure relief valve can offer, among other things, the following advantages: (1) Real-time control of the pressure supplied by the pump using the current consumed by the pump as a proxy for the pressure. (2) Prevention of the pump pressure exceeding a predetermined pressure threshold by electronically preventing the use of a mechanical pressure relief valve. (3) Reduction of manufacturing and maintenance costs by eliminating the need for a pressure relief valve.

[0016] Fig. Figure 1 is a schematic representation of an aftertreatment system 100 according to one embodiment. The aftertreatment system 100 is configured to receive exhaust gas (e.g., diesel exhaust) from an engine (e.g., a diesel engine) and reduce components of the exhaust gas such as NOx gases, CO, etc. The aftertreatment system 100 comprises a reducing agent storage tank 110 (hereinafter also referred to as "tank 110"), a reducing agent supply component 120, an SCR system 150, and a control unit 170.

[0017] Tank 110 contains an exhaust gas reducing agent formulated to facilitate the reduction of exhaust gas components (e.g., NOx) via a catalyst 154 integrated into the SCR system 150. In embodiments where the exhaust gas is diesel exhaust, the exhaust gas reducing agent may include a diesel emission fluid (DEF), which provides an ammonia source. Suitable DEFs include urea, an aqueous urea solution, or any other DEF (e.g., the DEF available under the trade name ADBLUE®).

[0018] The SCR system 150 is designed to capture and treat the exhaust gas (e.g., diesel exhaust) flowing through it. The SCR system 150 is fluidically coupled to the tank 110 to receive the reducing agent from the tank 110 via the reducing agent supply component 120, as described herein. The SCR system 150 comprises a housing 152, which defines an inlet 151 for supplying the exhaust gas from an engine (e.g., a diesel combustion engine) and an outlet 153 for the discharge of the treated exhaust gas. The SCR system 150 includes at least one catalyst 154, which is positioned within the internal volume formed by the housing 152. The catalyst 154 is formulated such that components of the exhaust gas, for example, NOx contained in the exhaust gas, are selectively reduced in the presence of an exhaust gas reducing agent.Any suitable catalyst 154 can be used, such as platinum-, palladium-, rhodium-, cerium-, iron-, manganese-, copper-, vanadium-based catalysts (including combinations thereof).

[0019] The catalyst 154 can be arranged on a suitable substrate, such as a ceramic (e.g., cordierite) or metallic (e.g., Kanthal) monolithic core, which may, for example, have a honeycomb structure. A washcoat can also be used as a support material for the catalyst 154. Such washcoat materials may include, for example, aluminum oxide, titanium dioxide, silicon dioxide, any other suitable washcoat material, or a combination thereof. The exhaust gas flows over and around the catalyst 154 in such a way that the NOx gases trapped in the exhaust gas are further reduced, resulting in an exhaust gas that is essentially free of carbon monoxide and NOx gases.

[0020] The reducing agent supply component 120 is fluidically coupled to the tank 110 and the SCR system 150 and is configured to supply the reducing agent from the tank 110 to the SCR system 150. The reducing agent supply component 120 comprises a pump 122, which is fluidically coupled to the tank 110 and a metering valve 126. The pump 122 can be a suitable pump, such as a centrifugal pump, a rotary pump, a vacuum pump, a plate pump, a diaphragm pump, or any other suitable pump. In certain embodiments, the pump 122 comprises a diaphragm pump.

[0021] In various embodiments, the pump includes a motor (e.g., the one in Fig. 3 Motor 224 shown), to drive the pump 122. For example, the pump 122 may be a diaphragm pump and the motor may be functionally coupled to the diaphragm to drive the diaphragm to pump the liquid. The torque exerted by the motor on the diaphragm, or the torque generated by the pump 122, corresponds to an operating pressure of the pump 122, i.e., the pressure to which the pump 122 applies the reducing agent. The motor may be operated using a suitable operating signal, for example, using a voltage in the range of 10 volts to 32 volts (e.g., 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, or 32 volts, including all intermediate ranges and values), a current, a pulse-width modulated (PWM) signal / command, or another suitable operating signal.

[0022] Furthermore, the torque generated by pump 122 is proportional to a value of the electrical operating parameter of the motor or pump 122. The value of the electrical operating parameter can, for example, be the current consumed by pump 122 or, alternatively, the motor of pump 122. Since the torque generated by pump 122 corresponds to the operating pressure of pump 122 and also to the value of the electrical operating parameter, the value of the electrical operating parameter allows conclusions to be drawn about the operating pressure of pump 122.

[0023] The value of the electrical operating parameter can therefore be used to determine the operating pressure of pump 122 and to prevent the operating pressure from exceeding a predetermined operating threshold. For example, the operating threshold can include a current threshold that corresponds to a pressure threshold of pump 122. In many embodiments, the pressure threshold of pump 122 can be in the range of 13,000 to 20,000 mPa (e.g., 13,000, 14,200, 15,400, 16,600, 17,800, or 20,000 mbar, including all intermediate ranges and values). In some embodiments, the pressure threshold of pump 122 can be based on an operating pressure of the SCR system 150 and can be easily set above the operating pressure of the SCR system 150.

[0024] In various embodiments, the operating threshold can be a variable that depends on one or more parameters of the pump 122. For example, the operating threshold can depend on a value of the operating signal provided to the pump 122. In certain embodiments, the operating signal can include an operating voltage used to operate the pump 122. For example, different operating voltages may be specified for pumps from different manufacturers, or the pump's operating voltage may vary based on the operating state of a motor fluidically coupled to the aftertreatment system 100 (e.g., operating the pump at lower voltages when the motor is under low load or idling, and operating the pump at higher voltages under high load or motor acceleration).In some embodiments, the operating voltage can range from 10 volts to 32 volts (e.g., 10, 12, 14, 16, 18, 20, 22, 24, 26, 27, 28, 29, 30, 31, or 32 volts, including all intermediate ranges and values). Other pump parameters set by the manufacturer can also be used for the operating threshold, or the parameters / thresholds can be set independently of the manufacturer's settings. In other embodiments, the operating signal can include a current, a PWM signal, comments, or another operating signal, and the operating threshold can depend on this.

[0025] The operating threshold can also depend on the operating temperature of pump 122. For example, high temperatures can cause pump 122 and / or a fluid pumped by pump 122 (e.g., a reducing agent) to heat up and become less dense. The lower density can decrease the torque applied by pump 122 to pump a predetermined mass or volume of the reducing agent. Conversely, cold temperatures can lead to an increase in the fluid's density, requiring pump 122 to apply a higher torque to pump the same predetermined mass or volume of fluid. In various embodiments, the operating threshold value is adjusted to accommodate fluctuations in the operating temperature range from -40°C to 80°C (e.g.,-40, -30, -20, -10, 0, 10, 20, 30, 40, 50, 60, 70 or 80 degrees Celsius, including all intermediate ranges and values).

[0026] Pump 122 is designed to receive the reducing agent from tank 110 and pressurize it to the pump's operating pressure. For example, a pump reservoir (not shown) can be positioned downstream of pump 122 and upstream of metering valve 126. Pump 122 can then continue pumping the reducing agent into the reservoir and increasing the pump's pressure to the operating pressure.

[0027] The metering valve 126 is selectively opened to allow the reducing agent, pressurized by the pump 122, to be supplied to the SCR system 150. The metering valve 126 may include a suitable valve, such as a throttle valve, a plate valve, a pressure-activated valve, an air-activated valve (e.g., an air injector), or another suitable valve. The metering valve 126 may include a nozzle (not shown) that is fluidically coupled to the SCR system 150 to supply it with the reducing agent. In various embodiments, the metering valve 126 or the nozzle enclosed in the metering valve 126 may be fluidically coupled to a mixer (not shown) positioned upstream of the SCR system 150.The reducing agent is supplied upstream of the SCR system 150 to increase its residence time. The exhaust gas flows through the aftertreatment system 100, thus improving the mixing of the reducing agent with the exhaust gas before it enters the SCR system 150. In one embodiment, the metering valve 126 comprises a solenoid coil, a valve needle in a valve seat, and a nozzle. In such embodiments, activation of the metering valve 126 includes activating the solenoid coil to move the distal end of the valve needle out of the valve seat, allowing the reducing agent to be pumped through the nozzle.

[0028] The reducing agent feed component 120 also includes a sensor circuit 130, which is communicatively coupled to the pump 122 and is configured to detect the value of the electrical operating parameter of the pump 122 and / or to determine the operating pressure of the pump 122 from this value. For example, the sensor circuit 130 can be structured to measure the current consumed by the pump 122 or the motor of the pump 122, which allows conclusions to be drawn about the operating pressure of the pump 122. The sensor circuit 130 can include sensors, processors, resistors, capacitors, and memory lookup tables, algorithms, or other instructions for determining the value of the electrical operating parameter of the pump 122.

[0029] The sensor circuit 130 can also be coupled to the control unit 170 and structured to provide the control unit 170 with output signals or output data according to the value of the electrical operating parameter. In various embodiments, the sensor circuit 130 can be communicatively coupled to the control unit 170 in a feedback loop, so that it receives input signals or input data for controlling an operating signal (e.g., a voltage) that is provided to the pump 122.

[0030] Fig. Figure 3 is a circuit diagram of a specific embodiment of a sensor circuit 230, which is included in a reducing agent supply component 220. The reducing agent supply component 220 also includes a pump 222, comprising a motor 224. The pump 222 may be a suitable pump, such as the pump 122 described herein. The reducing agent supply component 220 may be included in the post-treatment system 100 or in any other post-treatment system described herein. The sensor circuit 230 is communicatively coupled to the control unit 270, which may essentially correspond to the control unit 170 described in detail herein.

[0031] The sensor circuit 230 can optionally include a rotor position sensor (e.g., a Hall effect sensor) and an acceleration sensor (dv / dt) used to determine a torque generated by the pump's motor 224. In some embodiments, the control unit 270 can be configured to determine the rotor position (i.e., the position of a rotor of the motor 224) using a back EMF (electromotive force or other voltage) signal generated by the motor. In these embodiments, the rotor position sensor can be omitted, resulting in significant cost savings.

[0032] The sensor circuit comprises a proportional-integral differential (PID) controller or other processor and memory (“conversion logic”), including a non-transient, computer-readable medium for storing instructions to convert the torque information into current (I) consumed by the motor 224. The sensor circuit 230 also includes a filter “µ” (e.g., a low-pass filter, a high-pass filter, a band-pass filter, or another suitable filter) and one or more resistors “k”.

[0033] The sensor circuit 230 determines the value of the electrical operating parameter, which in some embodiments may include an operating current I. The value of the electrical operating parameter is communicated to the control unit 270. The sensor circuit 230 is in a feedback loop with the control unit 270 and is configured to send an operating signal, such as an input voltage (V) or an input current, a PWM signal, or another suitable input signal, to the motor 224 of the pump 222 to operate the pump 222. The control unit 270 compares the operating current I with a predefined operating threshold current (I*).

[0034] As previously described, the control unit 270 varies the value of the operating threshold based on the input voltage V (or another input signal) and the conversions thereto, which may differ for various speeds of the pump 222. If the operating current I exceeds the threshold current I*, the control unit 270 requests the sensor circuit 230 to limit the supplied input voltage V based on a maximum set / predefined operating threshold value in order to stop the supply of the input voltage V to the pump 222 or, alternatively, to the motor 224 of the pump 222, thus stopping the pump. In some embodiments, the pump 222 may be stopped as soon as the operating current I exceeds the threshold current I*. In this way, dynamic control of the operating pressure of the pump 222 is provided, so that the operating pressure of the pump 222 never exceeds an operating pressure threshold value (e.g.,(a maximum nominal pressure of the pump 222). Therefore, no passive pressure relief for excessive pressure build-up is required for the pump 222. Therefore, the reducing agent supply component 220 does not include a pressure relief valve.

[0035] Referring again to Fig. 1. The control unit 170 is communicatively coupled to the reducing agent supply component 120. In particular, the control unit 170 is communicatively coupled to each pump 122, the metering valve 126 and the sensor circuit 130 (e.g., the one in Fig. 3 sensor circuit shown230), which is enclosed in the reducing agent supply component 120. Fig. Figure 2 is a schematic block diagram of an embodiment of a control circuit 171, which may include the control unit 170. The control unit 170 may include a processor 172, a memory element 174 or other computer-readable medium, a receiver 178, and optionally a sensor 176. It should be noted that the control circuit 171 shows only one embodiment of a control circuit and any other control unit capable of performing the tasks described herein may also be used (e.g., the computer unit 630).

[0036] The processor 172 can comprise a microprocessor, a programmable logic controller (PLC), an ASIC chip, or another suitable processor. The processor 172 communicates with the memory 174 and is designed to execute instructions, algorithms, commands, or other programs stored in the memory 174.

[0037] Memory 174 encompasses all memory and storage components discussed here. For example, memory 174 can include the main memory and / or the cache of the processor 172. Memory 174 can also include one or more storage media (e.g., hard disks, flash drives, computer-readable media, etc.) located either locally or remotely from the device control unit 170. Memory 174 is designed to store allocation tables, algorithms, or instructions.

[0038] For example, memory 174 includes a pressure setting circuit 174a, which is configured to store instructions for setting an operating pressure of the pump based on the value of the electrical operating parameter of the pump provided by sensor circuit 130. For example, sensor 176 can be configured to receive an input signal (e.g., a current or voltage) corresponding to the value of the electrical operating parameter of pump 122 and to communicate the input signal to the pressure setting circuit 174a to set the operating pressure of pump 112.

[0039] The circuit for determining pressure 174a also includes instructions for setting an operating threshold value based on the value of an operating signal from pump 122 (e.g., a voltage in the range of 10 volts to 32 volts) and / or an operating temperature of the pump (e.g., in the range of -40 to 80 degrees Celsius). The circuit for determining pressure 174a also receives the value of the electrical operating parameter, for example, from sensor circuit 130, for example, via sensor 176, and compares the value of the electrical operating parameter (e.g., current consumed by motor 224 of pump 222) with the operating threshold value (e.g., a current threshold corresponding to a pressure threshold of the pump) to determine whether pump 122 exceeds the operating threshold value.

[0040] Memory 174 also includes a torque-adjusting circuit 174b, configured to send operating signals to the pump to start, stop, and / or control torque generated by the pump 122 (e.g., a motor driven by the pump 122). For example, the pressure-setting circuit 174a can provide the torque-adjusting circuit 174b with information about whether the value of the electrical operating parameter or another operating pressure value of the pump 122 is within or above the operating threshold. Based on this information, the torque-adjusting circuit 174b can control the torque of the pump 122, for example, by controlling the value of an operating signal (e.g., an operating voltage supplied to the pump 122) or by stopping the pump 122.

[0041] In some embodiments, the receiver 178 can be configured to generate an operating signal to adjust the torque produced by the pump 124. In other embodiments, the torque-adjusting circuit 174b can instruct the sensor circuit 130, which may be in a feedback loop with the control unit 170, to adjust the operating signal provided to the pump 122 to control the torque produced by the pump 122. The memory 174 also includes a dosing control circuit 174c, configured to selectively activate the metering valve 126, for example, via the receiver 178. The dosing control circuit 174c may include algorithms or lookup tables to determine a feed rate and / or feed frequency of the reducing agent to the SCR system 150, for example, based on one or more engine operating conditions (e.g.,a diesel engine), which is fluidically coupled to the aftertreatment system 100, an exhaust gas temperature, an exhaust gas pressure or another operating parameter.

[0042] During operation, the control unit 170 is configured to initialize the pump 122 in order to pressurize a reducing agent within the pump 122. For example, the torque-adjusting circuit 174b can instruct the sensor circuit 130 to initialize the pump 122 by outputting an operating signal to the pump 122 (e.g., an operating voltage with a value in the range of 10 to 32 volts, an operating current, or a PWM signal). The operating voltage can correspond to an operating pressure at which the reducing agent is to be supplied to the SCR system 150.

[0043] The control unit 170 opens the metering valve 126, thus supplying the reducing agent to the SCR system 150. The control unit 170 is configured to determine the value of the electrical operating parameter of the pump 122. For example, the circuit for setting the pressure 174a determines the value of the electrical operating parameter of the pump 122 (e.g., the current consumed by the motor of the pump 122), which allows the operating pressure of the pump 122 to be deduced as described herein.

[0044] The control unit 170 determines whether the value of the electrical operating parameter exceeds a predefined threshold. For example, the circuit for setting the pressure 174a determines whether the value of the electrical operating parameter (e.g., current consumed by the motor of pump 122) exceeds the predefined threshold (e.g., a current threshold that corresponds to a pressure threshold of pump 122).

[0045] If the value of the electrical operating parameter exceeds the predefined threshold, the control unit 170 stops the pump 122. For example, the torque-adjusting circuit 174b commands the sensor circuit 130 to stop the pump. Furthermore, in certain cases, the pump 122 may continuously pressurize the reducing agent, causing the operating pressure of the pump 122 to continue to build up. However, the metering valve 126 may remain closed, or the interval between openings of the metering valve may be set such that the pressure relief provided by the metering valve 126 does not occur frequently enough, or the duration for which the metering valve 126 remains open is not long enough to reduce the pressure buildup in the pump 122. In this scenario, the operating pressure of the pump 122 may continue to rise and exceed the operating pressure value.

[0046] In such cases, the control unit 170 stops the pump 122 to prevent further pressure build-up. Furthermore, the control unit 170 can be configured to activate the metering valve 126 while the pump 122 is stopped. For example, the metering control circuit 174c can continue to open the metering valve 126 while the pump 122 is off to introduce the reducing agent into the SCR system 150 to meet a reducing agent demand based on one or more operating parameters or conditions of the exhaust gas flowing through the aftertreatment system 100. The continuous introduction of reducing agent into the SCR system 150, even with the pump 122 stopped, reduces the pressure on the pump and thus also the operating pressure to below the pressure threshold of the pump 122.

[0047] In this way, any overpressure or pressure build-up in pump 122 is reduced without the use of a pressure relief valve. As soon as the pressure drops below the operating pressure threshold, indicated by the value of the electrical operating parameter falling below the specified operating threshold, the control unit 170 can restart pump 122.

[0048] The control unit 170 can also be configured to prevent excessive pressure build-up in pump 122 when pump 122 is started up. Since pump 122 or the reducing agent feed assembly 120 does not include a pressure relief valve, the reducing agent remaining in pump 122 from a previous operation may still be below the initial operating pressure of pump 122, even if the reducing agent feed assembly 120 and pump 122 have been switched off after the previous operating cycle. When pump 122 is restarted, for example at the beginning of a new operating cycle, the initial operating pressure of pump 122 may exceed a predefined initial threshold. Values ​​above this threshold can, for example, damage pump 122.

[0049] In various versions, the control unit 170 is also configured to determine an output value of the electrical parameter of pump 122 when pump 122 is started up. The output value of the electrical parameter indicates the output pressure of pump 122, i.e., the pressure of pump 122 at its initial start-up. As previously described, the output value of the electrical parameter can include the current consumed by the motor of pump 122. The control unit 170 determines whether the output value of the electrical parameter exceeds a predefined initial threshold. For example, the pressure determination circuit 174a can be configured to determine whether the output value of the electrical operating parameter exceeds a predefined initial threshold.

[0050] The predefined initial threshold can include an initial current threshold corresponding to an initial pressure threshold of pump 122. In certain embodiments, the initial threshold includes an initial pressure threshold of pump 122. In these embodiments, the control unit 170 (i.e., the pressure determination circuit 174a) is configured to determine an initial operating pressure value of pump 122 based on the output value of the electrical parameter. The control unit 170 determines whether the output operating pressure exceeds the initial pressure threshold. Similar to the predefined operating threshold, the control unit 170 can also be configured to adjust the initial threshold based on the value of an operating signal from the pump (e.g., an operating voltage in the range of 10 volts to 32 volts) and / or an operating temperature of the pump (e.g.,in the range of -40 to 80 degrees Celsius).

[0051] If the output value of the electrical parameter exceeds the original threshold, the control unit 170 stops the pump 122. This prevents the initial pressure from rising further above the original threshold. The control unit 170 can then open the metering valve 126 to introduce at least some of the pressurized reducing agent already in the pump 122 into the SCR system 150 while the pump 122 is stationary. This releases the pressure in the pump 122, causing the original operating pressure, and consequently the output value of the electrical parameter of the pump 122, to fall below the original threshold.In various versions, the original threshold value is adjusted so that the pump 122 can only be started against a non-pressurized reducing agent supply assembly, for example if the operating pressure on the discharge side of the pump 122 is zero or approximately zero when the pump 122 is started (e.g. in a range of +10%).

[0052] In some embodiments, the reducing agent feed assembly 120 may also include a return line (not shown) that fluidically couples the reducing agent feed assembly 120 to the tank 110. The return line can be used to prevent excessive pressure build-up and / or to reduce the pressure from the reducing agent feed assembly 120 once the reducing agent feed assembly 120 has been switched off. For example, the return line may include an orifice or a passive or active valve that opens as soon as the operating pressure of the pump 122 exceeds a pressure threshold and / or as soon as the reducing agent feed assembly 120 is switched off. Opening the valve allows at least some of the pressurized reducing agent to be routed back to the tank 110 through the return line, thus reducing the overpressure.

[0053] In some configurations, a blockage in a reducing agent supply line, return line, or nozzle may prevent the operating pressure of pump 122 from decreasing after a previous shutdown. This can result in "No Pressure" being displayed on the reducing agent supply assembly 120, making it impossible to determine the actual remaining pressure in the reducing agent supply assembly using the sensor circuit 130. Adjusting the initial threshold to a value that prevents pump 222 from starting when the reducing agent supply assembly 120 is already pressurized prevents excessive pressure buildup. In various configurations where the sensor circuit 130 includes a rotor position sensor (e.g., sensor 176), the initial threshold may include a threshold current determined by the rotor position sensor.The control unit 170 can determine the current consumed by the pump 122 and stop the pump 122 if the current consumption is too high. Furthermore, the metering valve 126 can be activated to reduce the pressure as soon as the reducing agent supply assembly 120 is switched on.

[0054] As soon as the output value of the electrical parameter or the original operating pressure of pump 122 exceeds the predefined initial threshold, the control unit 170 restarts pump 122. In this way, the pressure of pump 122 is reduced electronically without the use of passive pressure relief valves or any other mechanical pressure limiting mechanism. This reduces manufacturing and maintenance costs.

[0055] Although in Fig. Unless otherwise indicated, the aftertreatment system 100 may include sensors such as temperature sensors, pressure sensors, NOx sensors, oxygen sensors, ammonia sensors, and / or any other sensor. The control unit 170 may be communicatively coupled to one or more such sensors to receive and interpret signals from one or more of these sensors. The control unit 170 may use the information from one or more of these sensors to determine the exhaust gas flow conditions (e.g., to determine the dosage), the operating threshold, and / or the initial threshold. In certain embodiments, the control unit 170 may also be configured to receive and interpret data from temperature sensors, NOx sensors, oxygen sensors, ammonia sensors, and / or other sensors, each of which may be included in the aftertreatment system 100.

[0056] At Fig. Figure 4 is a schematic flow diagram of an example process 300 for introducing a reducing agent into a post-treatment system (e.g., post-treatment system 100 or 200) using a reducing agent feed assembly (e.g., reducing agent feed assembly 120 or 220) configured to be fluidically coupled to the post-treatment system. The reducing agent feed assembly comprises a pump (e.g., pump 122 or 222) and a metering valve (e.g., metering valve 126). The operations of process 300 can be expressed in the form of instructions on a non-transient computer-readable medium (e.g., memory 174 of the control unit 170, or main memory 636, read-only memory (ROM) 638, or storage device 640, which is embedded in the computer device 630). Fig. 19 is included). The computer-readable medium may be contained in a computer device (e.g., the computer device 630) designed to execute the instructions stored on the computer-readable medium in order to carry out the operations of procedure 300.

[0057] Method 300 includes starting the pump to pressurize a reducing agent in the pump to a pump operating pressure of 302. For example, the control unit 170 or 270 can start the pump 122 or 222, so that the motor (e.g., the motor 224) of the pump 122 or 222 applies a torque (e.g., to a diaphragm or membrane enclosed in the pump 122) to pressurize the reducing agent in the pump.

[0058] In various configurations, an output value for the pump's electrical parameter is set at 304. This output value indicates the pump's pressure output. For example, the control unit 170 or 270 sets the output value of the electrical parameter for pump 122 or 222, which may include the current consumed by the pump's motor (e.g., motor 224) during startup.

[0059] The system determines whether the output value of the electrical parameter exceeds a predefined initial threshold at 306. For example, control unit 170 or 270 determines whether the output value of the electrical parameter (e.g., the output current consumed by the motor of pump 122 or 222) exceeds the predefined initial threshold (e.g., the initial threshold current corresponding to an initial threshold pressure of pump 122). In response to the initial threshold exceeding the specified threshold, the pump is stopped at 308. For example, control unit 170 or 270 stops pump 122 or 222.

[0060] In some configurations, the metering valve is activated while the pump is stopped at 310. Activating the metering valve (e.g., metering valve 126) allows the reducing agent to be fed into the post-treatment system while the pump (e.g., pump 122 or 222) is stationary. This releases pressure and reduces the pressure in the pump below the initial threshold. The pump (e.g., pump 122 or 222) is then restarted to pressurize the reducing agent until the pump's operating pressure is reached.

[0061] The metering valve opens at 312 to supply a reducing agent to the aftertreatment system. For example, the control unit 170 instructs the metering valve 126 to open, thus supplying the reducing agent to the aftertreatment system 100 at the operating pressure of pump 122. The value of the pump's electrical operating parameter is set at 314. For example, the control unit 170 or 270 sets the value of the electrical operating parameter of pump 122 or 222 (e.g., the current consumed by the motor of pump 122 or 222). The value of the electrical operating parameter indicates the pump's operating pressure.

[0062] The system determines whether the value of the electrical operating parameter exceeds a predefined threshold at 316. If the value of the electrical operating parameter exceeds the predefined threshold, the pump is stopped at 318. For example, the control unit 170 or 270 determines whether the value of the electrical operating parameter, for example, the current consumed by the motor of pump 122 or 222, exceeds the operating threshold, for example, the threshold current corresponding to a threshold operating pressure of pump 122 or 222. If the value of the electrical operating parameter exceeds the operating threshold, the control unit 170 or 270 stops pump 122 or 222.

[0063] In various configurations, the metering valve is activated while the pump is stopped at 320. For example, the control unit 170 activates the metering valve 126 to supply the reducing agent to the SCR system 150 of the aftertreatment system 100. This releases the pressure built up in pump 122 and reduces the operating pressure of pump 122. The system then checks whether the value of the pump's electrical operating parameter has fallen below the operating threshold at 322. If the value of the pump's electrical operating parameter falls below the operating threshold, the pump is restarted at 324.

[0064] For example, the control unit 170 or 270 activates the metering valve (e.g., metering valve 126) for a specified time to supply the reducing agent to the aftertreatment system 100, thereby reducing the operating pressure of pump 122 or 222 while pump 122 or 222 is off. After the specified time (e.g., 1, 2, 4, 6, 8, or 10 seconds, including all intermediate ranges and values) or in real time, the control unit 170 or 270 again determines whether the value of the electrical operating parameter corresponding to the operating pressure of pump 122 or 222 has fallen below the operating threshold. If the value of the electrical operating parameter still exceeds the operating threshold, the control unit 170 or 270 continues to activate metering valve 126 while pump 122 or 222 is off to further reduce the operating pressure.If the value of the electrical operating parameter falls below the operating threshold, the control unit 170 or 270 restarts the pump 122 or 222.

[0065] In various iterations, procedure 300 can include stopping the pump (e.g., pump 122 / 222) if the reducing agent feed assembly (e.g., reducing agent feed assembly 120 / 220) is pressurized during start-up. For example, a blockage in a reducing agent feed line or nozzle can prevent pressure release. When the pump is started, this can lead to overpressure in the reducing agent feed assembly. To avoid this scenario, the pump is not started if at least part of the reducing agent feed assembly (e.g., fluidically coupled to the discharge side of pump 122 / 222) is pressurized.

[0066] In some versions, procedure 300 includes starting up the pump when the operating pressure is below the initial threshold. The electrical operating parameter is determined. If the electrical parameter is below the specified initial operating pressure threshold, the pump's operating pressure must be below a specified value. For example, if a reducing agent supply line for introducing the reducing agent from pump 122 / 222 is disconnected or leaks, the sensor circuit 130 / 230 determines that the reducing agent supply assembly 120 / 220, or at least a part of the reducing agent supply assembly 120 / 220 on the discharge side of pump 122 / 222, is not pressurized.

[0067] The pump 122 / 222 is therefore started up. However, the torque of the motor (e.g., motor 224) of the pump 122 / 222 may be very low because the reducing agent supply line is disconnected, resulting in little or no load on the motor. This low torque corresponds to a low electrical operating parameter (e.g., current), indicating that the reducing agent supply line is disconnected or has a leak. The control unit 170 / 270 can thus limit the operating pressure of the pump 122 / 222 to within a predefined range, thereby preventing further damage to the pump 122 / 222 or the reducing agent supply line. In some configurations, procedure 300 may also include generating a fault code or illuminating a malfunction indicator lamp (MIL) in such situations.

[0068] Fig. Figures 5-6 are various diagrams of operating signals, operating pressure, pump speed, and metering commands for a first pump including mechanical pressure relief (MPR) and a second pump including electronic pressure relief (EPR) that does not include a mechanical pressure relief valve and provides pressure relief by means of the systems and methods described here (e.g., Method 300). Fig. Figure 5 shows a diagram of an example PWM command or signal for pump operation. Fig. Figure 6 is a diagram for dosing or supplying a reducing agent at 10 bar operating pressure using the PWM command from Fig. 5 shown.

[0069] Fig. Figure 7 shows a diagram of the operating pressure and pump speed of the first pump in response to a test PWM command. Fig. Figure 8 contains a diagram of the operating pressure and pump speed of the second pump in response to the same test PWM command, and Fig. 9 includes the diagrams of Fig. 7 and Fig. 8, which were superimposed. The second pump was equipped with a speed error control option or function. The speed error control option switches off the second pump if it has not reached a predetermined speed after a certain time, for example, due to torque limitation (e.g., by a defective or disconnected reducing agent supply line). Large fluctuations in the operating pressure of the second pump are observed in relation to the first pump when the second pump switches off and on again due to the pump speed.

[0070] Fig. Item 10 contains a diagram of the operating pressure and pump speed of the second pump in response to the same test PWM command without the speed error control option, and Fig. 11 includes the diagrams of Fig. 7 and Fig. 11, which were superimposed. The second pump has no option or function for speed error control. Much smaller fluctuations in the operating pressure of the second pump are observed with respect to the first pump, so that the performance of the second pump is essentially similar to the performance of the first pump. Fig. Figures 12-16 show the performance of the first and second pumps under different dosing requirements.

[0071] Fig. 17 and Fig. Figure 18 shows the power consumption of a new pump, a pump after 20,000 operating hours, and a third pump after 20,000 operating hours at maximum dosing, with the pumps operating at 14 volts and 27 volts. An increase in pump pressure at the operating voltages of 14 volts and 27 volts results in a correspondingly higher power consumption. The pressure-power consumption graph for the new pump does not differ significantly between the pump after 20,000 operating hours and the pump after 20,000 operating hours at maximum dosing. This suggests that the relationship between current and pressure remains remarkably constant over the entire service life of the pump. Therefore, the relationship between current and pressure can be reliably implemented in a lookup table or algorithm to determine the pump's operating pressure using the current consumed by the pump.

[0072] In some embodiments, the control unit 170, 270 or any of the control units described herein may be a system computer of a device or system which includes the aftertreatment system 100 or 200 (e.g. a vehicle, an engine or a generator set, etc.). Fig. Figure 19, for example, is a block diagram of a computer device 630 according to an illustrative implementation. The computer device 630 can be used to execute any of the methods or processes described herein, for example, method 400. In some embodiments, the controller 170 or 270 may include the computer device 630. The computer device 630 includes a bus 632 or other transmission component for information transfer. The computer device 630 may also include one or more processors 634 or processing circuits coupled to the bus for information processing.

[0073] The computer device 630 also includes main memory 636, such as random-access memory (RAM) or other dynamic storage device coupled to bus 632, for storing information and instructions to be executed by processor 634. Main memory 636 can also be used to store positional information, temporary variables, or other intermediate information during the execution of instructions by processor 634. The computer device 630 may further include read-only memory (ROM) 638 or other static storage unit coupled to bus 632 for storing static information and instructions for processor 634. A storage device 640, such as solid-state memory, a magnetic disk, or an optical disk, is coupled to bus 632 to persistently store information and instructions.

[0074] The computer device 630 can be connected via bus 632 to a display 635, such as a liquid crystal display or an active matrix display, for showing information to a user. An input unit 642, such as a keyboard or alphanumeric keypad, can be connected via bus 632 for transmitting information and selecting instructions for the processor 634. In another implementation, the input unit 642 includes a touchscreen display 644.

[0075] According to various implementation configurations, the procedures and methods described herein can be implemented by the computer device 630 in response to the processor 634, which executes a series of instructions contained in the main memory 636 (e.g., the operations of procedure 400). These instructions can be read into the main memory 636 from another non-transitory, computer-readable medium, such as the storage unit 640. The execution of the series of instructions contained in the main memory 636 causes the computer device 630 to perform the operations described herein. Alternatively, one or more processors in a multiprocessor arrangement can be used to execute the instructions contained in the main memory 636. In alternative implementation configurations, wired circuits can be used instead of, or in combination with, software instructions to implement the described configurations.Therefore, the implementation methods are not limited to a specific combination of hardware circuitry and software.

[0076] Although an example computer in Fig. As described in section 19, the implementation methods described in this specification can be implemented in other types of digital electronic circuits or in computer software, firmware or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them.

[0077] Implementation methods described in this specification can be implemented in digital electronic circuitry or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. The implementation methods described in this specification can be implemented as one or more computer programs, that is, as one or more modules of computer program instructions encoded on one or more computer storage media for execution by, or control of, data processing equipment. Alternatively or additionally, the program instructions can be implemented in an artificially generated propagated signal, e.g.,A computer storage medium may be encoded in a machine-generated electrical, optical, or electromagnetic signal, which is produced to encode information for transmission to a suitable receiving device for execution by a data processing device. A computer storage medium may be or include: a computer-readable storage unit, a computer-readable storage substrate, a serial or dynamic read / write memory or device, or a combination of one or more of these. Furthermore, although a computer storage medium is not a propagated signal, a computer storage medium may be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium may also be or include one or more separate components or media (e.g., multiple CDs, disks, or other storage devices).Therefore, the computer storage medium is both tangible and non-transient.

[0078] The operations described in this specification can be performed by a data processing device using data stored on one or more computer-readable storage devices or received from other sources. The term "data processing device" or "computer device" includes all types of devices, equipment, and machines for processing data, including, for example, a programmable processor, a computer, a system-on-a-chip, or systems on multiple chips, or combinations thereof. The device may include a specialized logic circuit, such as an FPGA (general-purpose circuit) or an ASIC (application-specific integrated circuit). In addition to the hardware, the device may also include code that creates an execution environment for the computer program in question, such as...A code that represents processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of these. The device and execution environment can implement various computing infrastructure models, such as web services, distributed computing, and geographically distributed computing infrastructures.

[0079] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or process languages, and it can be used in any form, including as a standalone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in a section of a file that contains other programs or data (e.g., one or more scripts stored in a markup language document), in a single dedicated file for the program in question, or in several coordinated files (e.g., files containing one or more modules, subroutines, or portions of code).A computer program can be deployed to run on one computer or on multiple computers located in one place or distributed across multiple locations and interconnected by a data transmission network.

[0080] Processors capable of executing a computer program include, for example, both general-purpose and specialized microprocessors, and one or more processors of any type of digital computer. Generally, a processor receives instructions and data from read-only memory or random-access memory, or both. The essential elements of a computer are a processor for performing operations according to instructions and one or more storage devices for storing instructions and data. Generally, a computer also includes, or is functionally coupled for receiving or transmitting data, or both, one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks. However, a computer does not necessarily have to include these devices.Units suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by or integrated within specialized logic circuitry.

[0081] It should be noted that the term "example", as used here to describe different embodiments, is intended to indicate that such embodiments are possible examples, representations and / or illustrations of possible embodiments (and that such a term is not necessarily intended to imply that such embodiments are exceptional or outstanding examples).

[0082] The term "coupled" and similar terms used herein refer to the direct or indirect connection of two elements. This connection can be stationary (e.g., permanent) or movable (e.g., removable or detachable). This connection can be achieved by integrally forming the two elements, or the two elements and any further intermediate elements, as a single, unified body, or by fixing the two elements, or the two elements and any further intermediate elements, to one another.

[0083] It should be noted that the structure and arrangement of the various exemplary embodiments serve only for illustration. Although only some embodiments are described in detail in this disclosure, those skilled in the art will readily recognize upon reading this disclosure that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and sections of the various elements, values ​​of parameters, assembly arrangements, use of materials, colors, orientations, etc.) without significantly deviating from the new teachings and advantages of the subject matter described herein. Furthermore, it is understood that features from one embodiment disclosed herein can be combined with features from other embodiments disclosed herein, as is known to those skilled in the art.Further substitutions, modifications, changes and omissions can also be made in the design, operating conditions and arrangement of the various exemplary embodiments without deviating from the scope of the present invention.

[0084] Although this patent specification contains many specific embodiment details, these should not be interpreted as limiting the scope of all inventions or claims, but rather as descriptions of features specific to certain embodiments of certain inventions. Certain features described in this patent specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in several embodiments or in any suitable subcombination.Furthermore, although the foregoing features may be described in such a way as to function in certain combinations and may initially be claimed as such, in some cases one or more features from a claimed combination may be excluded from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Claims

[1] Aftertreatment system (100) comprising: a selective catalytic reduction system (150) comprising a catalyst (154) for reducing components of an exhaust gas; a reducing agent storage tank (110); a reductant supply assembly (120, 220) fluidly coupled to the reductant storage tank (110) and the selective catalytic reduction system (150), the reductant supply assembly (120, 220) comprising a pump (122, 222) and a metering valve (126) fluidly coupled to the pump (122, 222); a sensor circuit (130, 230) configured to detect a rotor position and an acceleration from which a torque generated by the pump (122, 222) can be determined; and a controller (170, 270) communicatively coupled to the reductant supply component (120, 220) and the sensor circuit (130, 230), the controller (170, 270) being configured to: initializing the pump (122, 222) to pressurize a reducing agent in the pump (122, 222), the metering valve (126) opens and thereby supplies the reducing agent to the selective catalytic reduction system (150), the torque generated by the pump (122, 222) is determined based on the rotor position and acceleration detected by the sensor circuit (130, 230), the torque being indicative of an operating pressure of the pump (122, 222), and in response to the torque exceeding a threshold, the pump (122, 222) stops. [2] The aftertreatment system (100) of claim 1, wherein the controller (170, 270) is configured to activate the metering valve (126) while the pump (122, 222) is at a standstill, thereby introducing the reductant through the metering valve (126) into the selective catalytic reduction system (150) while the pump (122, 222) is at a standstill. [3] The aftertreatment system (100) of claim 2, wherein the controller (170, 270) is further configured to restart the pump (122, 222) in response to the torque falling below the threshold. [4] The aftertreatment system (100) of claim 1, wherein the controller (170, 270) is configured to adjust the threshold based on the value of an operating signal. [5] The aftertreatment system (100) of claim 4, wherein the controller (170, 270) is configured to adjust the threshold based on the operating temperature of the pump (122, 222). [6] Aftertreatment system (100) comprising: a selective catalytic reduction system (150) comprising a catalyst (154) for reducing components of an exhaust gas; a reducing agent storage tank (110); a reductant supply assembly (120, 220) fluidly coupled to the reductant storage tank (110) and the selective catalytic reduction system (150), the reductant supply assembly (120, 220) comprising a pump (122, 222) and a metering valve (126) fluidly coupled to the pump (122, 222); a sensor circuit (130, 230) configured to detect a rotor position and an acceleration from which a torque generated by the pump (122, 222) can be determined; and a controller (170, 270) communicatively coupled to the reductant supply component (120, 220) and the sensor circuit (130, 230), the controller (170, 270) being configured to: initializing the pump (122, 222) to pressurize a reducing agent in the pump (122, 222), the metering valve (126) opens and thereby supplies the reducing agent to the selective catalytic reduction system (150), the torque generated by the pump (122, 222) is determined based on the rotor position and acceleration detected by the sensor circuit (130, 230), determines a current value of a current consumed by the pump (122, 222) based on the determined torque generated by the pump (122, 222), the current value indicating an operating pressure in the pump (122, 222), and in response to the current value exceeding a predetermined current threshold, stopping the pump (122, 222). [7] Reductant supply assembly (120, 220) comprising: a pump (122, 222); a metering valve (126) fluidly coupled to the pump (122, 222); a sensor circuit (130, 230) configured to detect parameters from which a torque generated by the pump (122, 222) can be determined; and a controller (170, 270) communicatively connected to the pump (122, 222) and the sensor circuit (130, 230), the controller (170, 270) being configured to: initializing the pump (122, 222) to pressurize a reducing agent in the pump (122, 222), the metering valve (126) opens and thus expels the reducing agent through the valve, the torque generated by the pump (122, 222) is determined based on the parameters detected by the sensor circuit (130, 230), wherein the torque indicates an operating pressure of the pump (122, 222), in response to the torque exceeding a threshold, stopping the pump (122, 222), and the metering valve (126) is activated while the pump (122, 222) is at a standstill, wherein the reducing agent is expelled through the metering valve (126) while the pump (122, 222) is at a standstill. [8] The reductant delivery assembly (120, 220) of claim 7, wherein the controller (170, 270) is further configured to restart the pump (122, 222) in response to the torque falling below the threshold. [9] The reductant supply assembly (120, 220) of claim 7, wherein the controller (170, 270) is configured to adjust the threshold based on the value of an operating signal of the pump (122, 222). [10] The reductant supply assembly (120, 220) of claim 7, wherein the controller (170, 270) is configured to adjust the thresholds based on the operating temperature of the pump (122, 222). [11] Reductant supply assembly (120, 220) comprising: a pump (122, 222); a metering valve (126) fluidly coupled to the pump (122, 222). a sensor circuit (130, 230) configured to detect a rotor position and an acceleration from which a torque generated by the pump (122, 222) can be determined; and a controller (170, 270) communicatively connected to the pump (122, 222) and the sensor circuit (130, 230), the controller (170, 270) being configured to: initializing the pump (122, 222) to pressurize a reducing agent in the pump (122, 222), the metering valve (126) opens and thus expels the reducing agent through the valve, the torque generated by the pump (122, 222) is determined based on the rotor position and acceleration detected by the sensor circuit (130, 230), determines a current value of a current consumed by the pump (122, 222) based on the determined torque generated by the pump (122, 222), the current value indicating an operating pressure in the pump (122, 222), and in response to the current value exceeding a predetermined current threshold, stopping the pump (122, 222). [12] A method of operating a reductant supply assembly (120, 220) comprising a pump (122, 222) and a metering valve (126) structured to be fluidly coupled to an aftertreatment system (100), the method comprising: Initializing the pump (122, 222) to pressurize a reducing agent in the pump (122, 222) to the operating pressure of the pump (122, 222); Opening the metering valve (126) and supplying the reducing agent to the aftertreatment system (100); Determining a torque generated by the pump (122, 222); Determining a current value of a current consumed by the pump (122, 222) based on the determined torque generated by the pump (122, 222), the current value being indicative of the operating pressure in the pump (122, 222); Stopping the pump (122, 222) in response to the current value exceeding a predetermined current threshold; and Activating the metering valve (126) while the pump (122, 222) is at a standstill, wherein the reducing agent is introduced into the aftertreatment system (100) while the pump (122, 222) is at a standstill. [13] The method of claim 12, further comprising: Restarting the pump (122, 222) in response to the torque falling below the thresholds. [14] Control circuit (171) comprising: a controller (170, 270) configured to be communicatively coupled to a reductant supply assembly (120, 220) comprising a pump (122, 222) and a metering valve (126) fluidly coupled to the pump (122, 222) and a sensor circuit (130, 230), the controller (170, 270) comprising: a torque adjustment circuit (174b) configured to initialize the pump (122, 222) to pressurize a reducing agent in the pump (122, 222) and to determine a torque generated by the pump (122, 222) based on parameters sensed by the sensor circuit (130, 230) from which the torque is determinable, a dosing control circuit (174c) configured to open the dosing valve (126) and thus expel a reducing agent through the valve, and a pressure determination circuit (174a) configured to determine an operating pressure of the pump (122, 222) based on the torque wherein the pressure determination circuit (174a) is configured to stop the pump (122, 222) in response to the torque exceeding a threshold, and wherein the metering control circuit (174c) is configured to activate the metering valve (126) while the pump (122, 222) is at a standstill, wherein the reducing agent is expelled through the metering valve (126) while the pump (122, 222) is at a standstill. [15] The control circuit (171) of claim 14, wherein the torque adjusting circuit (174b) is configured to restart the pump (122, 222) in response to the torque falling below the threshold. [16] The control circuit (171) of claim 15, wherein the pressure determining circuit (174a) is further configured to determine the output value of the electrical parameter of the pump (122, 222) upon startup of the pump (122, 222), the output value of the electrical parameter being indicative of the output pressure of the pump (122, 222), and to determine whether the output value of the electrical operating parameter exceeds a predetermined initial threshold; and wherein the torque adjusting circuit (174b) is configured to stop the pump (122, 222) in response to the value of the electrical operating parameter exceeding the operating threshold. [17] The aftertreatment system (100) of claim 1, wherein the sensor circuit (130, 230) includes a rotor position sensor and an acceleration sensor used to determine the torque generated by the pump (122, 222). [18] The aftertreatment system (100) of claim 17, wherein the rotor position sensor is a Hall effect sensor. [19] The aftertreatment system (100) of claim 1, wherein the rotor position is detected using a counter electromotive force signal generated by the pump (122, 222).

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