Temperature estimation for sensor

Abstract

Method for controlled heating of a sensor (150; 220) of a post-treatment system (100), the method comprising: Accessing a multitude of parameters, the multitude of parameters including exhaust gas mass flow, outlet temperature, ambient air temperature and ambient air velocity; Calculating a temperature of the sensor (150; 220) based on a thermal model and the called plurality of parameters, wherein a first thermal model is selected when the exhaust mass flow is above a predetermined threshold, and a second thermal model when the exhaust mass flow is not above the predetermined threshold, wherein the predetermined threshold is an exhaust mass flow at an idle speed of an engine; Comparing the calculated temperature with a threshold temperature, where the threshold temperature is between 130 degrees Celsius and 160 degrees Celsius; and Activating a controlled heating process for the sensor (150; 220) in response to the calculated temperature being below the threshold temperature, wherein the controlled heating process includes activating a heater to heat the sensor (150; 220).

Description

REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims the priority and rights of the preliminary US patent application No. 62 / 428,065, filed on November 30, 2016, entitled “Temperature Estimation for Sensor”, the entire disclosure of which is incorporated herein by reference. TECHNICAL AREA

[0002] The present application deals generally with the field of aftertreatment systems for internal combustion engines. BACKGROUND

[0003] In combustion engines such as diesel engines, nitrogen oxide compounds (NOx) can be produced. x -compounds) are released in the exhaust gas. To reduce NO x -Emissions, an SCR process can be used to reduce the NO xSCR converts oxidizing compounds into neutral compounds such as diatomic nitrogen, water, or carbon dioxide using a catalyst and a reducing agent. The catalyst may be contained within a catalyst chamber of an exhaust system, such as that of a vehicle or power generation unit. A reducing agent, for example, ammonia anhydride, aqueous ammonia solution, or urea, is typically introduced into the exhaust stream upstream of the catalyst chamber. To introduce the reducing agent for the SCR process into the exhaust stream, an SCR system may meter or otherwise introduce the reducing agent via a dosing module, which vaporizes or sprays the reducing agent upstream of the catalyst chamber into an exhaust pipe of the exhaust system. The SCR system may include one or more sensors to monitor the conditions within the exhaust system.

[0004] Documents US 2004 / 0 086 023 A1, US 2007 / 0 118 338 A1, US 2016 / 0 290 260 A1 and DE 10 2006 035 449 A1 disclose further prior art. PRESENTATION OF THE INVENTION

[0005] The present invention is defined by the method for controlled heating of a sensor of a post-treatment system according to the features of independent claim 1 and the system according to the features of dependent claim 7. The dependent claims relate to optional embodiments.

[0006] The implementations described herein relate to the temperature estimation of a sensor for an exhaust system, such as the tip of an NO sensor. x-Sensors. One implementation involves a method for the controlled heating of a sensor for an aftertreatment system. The method includes accessing several parameters, including exhaust gas mass flow, outlet temperature, ambient air temperature, and ambient air velocity; calculating the sensor's temperature based on a thermal model and the accessed parameters; comparing the calculated temperature to a threshold temperature; and activating a controlled heating process for the sensor in response to the calculated temperature falling below the threshold temperature. The controlled heating method may include activating a heater to warm the sensor. The threshold temperature can be selected based on potential condensation.

[0007] In some implementations, the threshold temperature may be between 130°C and 160°C or between 140°C and 150°C. The procedure may involve accessing a key parameter as an activation condition. The thermal model may be based on a tuning calibration process to determine one or more calibration values ​​for parameters of the thermal model.

[0008] Another implementation involves a system comprising a sensor, a heater thermally connected to the sensor, and a controller electrically connected to both the sensor and the heater. The controller can be configured to access multiple parameters, including exhaust gas mass flow, outlet temperature, ambient air temperature, and ambient air velocity; to calculate the sensor's temperature based on a thermal model and the accessed parameters; to compare the calculated temperature with a threshold temperature; and to activate a controlled heating process for the sensor if the calculated temperature falls below the threshold. This controlled heating process can involve activating the heater to warm the sensor. The threshold temperature can be selected based on potential condensation.

[0009] In some implementations, the threshold temperature can be between 130°C and 160°C or between 140°C and 150°C. The controller can also be configured to access a key-on parameter as an activation condition. The thermal model can be based on a tuning calibration process to determine one or more calibration values ​​for parameters of the thermal model.

[0010] Another implementation relates to a procedure for calibrating one or more parameter values ​​for a thermal model. This procedure involves setting one or more constraints on one or more physical or tunable parameters of a post-treatment system with a sensor, generating a Latin Hypercube set of calibrations, simulating each calibration of the generated Latin Hypercube set of calibrations, and generating calibration values ​​for the parameters of the thermal model based on the simulated calibrations.

[0011] In some implementations, the simulation of each of the calibrations of the generated Latin Hypercube set of calibrations can be performed in parallel. SHORT DESCRIPTION

[0012] The details of one or more implementations are set forth in the accompanying drawings and the description below. Further features, aspects, and advantages of the disclosure will become apparent from the description, the drawings, and the claims, for which the following applies: Fig. Figure 1 is a schematic diagram of an exemplary selective catalytic reduction system with an exemplary reducing agent supply system for an exhaust system; Fig. Figure 2 is a side cross-sectional view of a sensor array positioned within an exemplary exhaust system; Fig. Figure 3 is a perspective view of the sensor arrangement of Fig. 2; Fig. Figure 4 is a cross-sectional flow velocity profile of the sensor arrangement of Fig. 2, which shows a flow velocity profile outside and inside the sensor array; Fig. Figure 5 is a process diagram of an implementation of a method for determining the temperature of a sensor or a component of a sensor; Fig. Figure 6 is a process diagram for activating a controlled heating process in response to the temperature of a sensor or a sensor component; Fig. Figure 7 is a process diagram for tuning a calibration for the procedure for determining the temperature of a sensor or a component of a sensor. Fig. 5; Fig. Figure 8 is a graphical diagram representing an estimated temperature, which the process of Fig. 5 implemented in relation to a measured temperature; and Fig. Figure 9 is a graphical diagram showing a control parameter for the controlled heating process of Fig. 6 represents an estimated temperature, which the process of Fig. 5 implemented in relation to a measured temperature.

[0013] It should be noted that some or all of the figures are schematic representations for illustrative purposes. The figures are provided to illustrate one or more implementations with the explicit understanding that they are not to be used to limit the scope or meaning of the claims. DETAILED DESCRIPTION

[0014] More detailed descriptions of various concepts related to and implementations of methods, devices, and systems for temperature estimation of a sensor for an exhaust system follow. The various concepts presented above and described in detail below can be implemented in numerous ways, as the described concepts are not limited to a specific implementation method. Examples of specific implementations and applications are provided primarily for illustrative purposes. I. Overview

[0015] In some exhaust systems, a sensor module can be positioned downstream of an SCR catalyst to detect one or more emissions in the exhaust stream behind the SCR catalyst. For example, a NOₓ sensor can detect NOₓ emissions. x A CO sensor and / or a particulate matter sensor are positioned downstream of the SCR catalyst to measure NO xto detect CO and / or particulate matter in the exhaust gas leaving the vehicle's tailpipe. Such emission sensors can be useful for providing feedback to a control unit to modify an operating parameter of the vehicle's aftertreatment system. For example, a NO x -Sensor can be used to measure the amount of NO x to detect the NOₓ leaving the vehicle's exhaust system, and if the detected NOₓ x If the CO level is too high or too low, the control unit can modify the amount of reducing agent supplied by a dosing module. A CO and / or a particulate matter sensor can also be used.

[0016] The aforementioned sensors include components such as tips, inlet pipes, etc., which take samples of the exhaust gas from the exhaust system so that the sensor can determine the quantity and / or presence of NO. xCO and / or particulate matter are detected within the exhaust gas. Such components, located within the exhaust system, are exposed to high exhaust gas temperatures during operation. However, when the exhaust system is not in operation, for example, when an engine fluidically coupled to the exhaust system is switched off, the sensor and its associated components exposed to the exhaust gas can cool to ambient temperature. Since the exhaust system vents to the atmosphere, ambient conditions such as humidity, dew point, etc., can also be present within the exhaust system, and are particularly relevant for the sensor and its associated components exposed to the exhaust gas.When the exhaust system is in operation, such as when an engine is running in fluid contact with the exhaust system, the temperature of the sensor and its associated components exposed to the exhaust gas is heated by the exhaust gas flowing through the system. Rapid temperature rises or falls in the sensor and / or its components can lead to thermal shock and component failure, such as the formation of cracks in the sensor tip and / or housing due to condensation and rapid transition to the gas phase on and / or within the sensor. Such sensor and / or component failures can result in inaccurate readings or false indications from the sensor, which may then require repair and / or replacement.

[0017] In some implementations, a controller can operate a heater to increase and / or control the temperature drop of the sensor and / or its associated components. The heater may be located inside the sensor. The controller can operate the heater to gradually raise the temperature of the sensor and / or its associated components, which are exposed to exhaust gas in the exhaust system, thus reducing instances of temperature shock. In other words, the controller can operate the sensor heater so that the temperature of the sensor and / or its associated components gradually rises to a predefined or operating temperature.

[0018] In some implementations, heating control can be based on the temperature of the sensor and / or an associated component. The temperature, such as a peak temperature, can be used by the controller to estimate whether the sensor and / or associated components are above or below a threshold dew point value, in order to control a dew point heating strategy for the sensor. That is, if the temperature of the sensor and / or associated component is below a predefined threshold, a controlled heating process can be initiated to eliminate any dew that may have formed on or within the sensor and / or associated component. If the temperature of the sensor and / or associated component is at or above the predefined threshold, the controlled heating process will likely not be initiated.In some cases, two or more predefined thresholds can be used. A first predefined threshold can correspond to an initial transition point, and a second predefined threshold can correspond to a second transition point. The initial transition point can be chosen based on a lower temperature at which dew is unlikely to form but can account for potential temperature estimation errors. The second transition point can be chosen based on a higher temperature at which dew is unlikely to form and which is sufficiently high that potential temperature estimation errors would still result in a temperature high enough that dew is unlikely to form.

[0019] In some implementations, the peak temperature may be based on an ambient temperature and a temperature within the exhaust system, such as an SCR outlet temperature. The ambient temperature and the SCR outlet temperature can be used with a lookup table to determine a parameter that indicates an estimated peak temperature. Such an implementation may not account for the exhaust flow velocity and / or other exhaust flow conditions within the system that could influence the peak temperature. Accordingly, a physically based model of the peak temperature can provide a more accurate estimate. A more accurate peak temperature estimate can be used to control the heating and / or controlled cooling of the sensor and / or associated components to reduce instances of temperature shock. II. Overview of the post-treatment system

[0020] Fig. Figure 1 shows an aftertreatment system 100 with an exemplary reducing agent supply system 110 for an exhaust system 190. The aftertreatment system 100 includes a particulate filter, for example a diesel particulate filter (DPF) 102, as well as the reducing agent supply system 110, a decomposition chamber or reactor tube 104, an SCR catalyst 106 and a sensor 150.

[0021] The DPF 102 is configured to remove particulate matter, such as soot, from the exhaust gas flowing in the exhaust system 190. The DPF 102 includes an inlet through which the exhaust gas enters and an outlet through which the exhaust gas exits after the particulate matter has been substantially filtered from the exhaust gas and / or converted into carbon dioxide.

[0022] The decomposition chamber 104 is configured to convert a reducing agent, such as urea, aqueous ammonia solution, or DEF, into ammonia. The decomposition chamber 104 includes a reducing agent supply system 110 with a metering module 112, which is configured to meter the reducing agent into the decomposition chamber 104. In some implementations, the reducing agent is injected upstream of the SCR catalyst 106. The reducing agent droplets then undergo the processes of evaporation, thermolysis, and hydrolysis to form gaseous ammonia within the exhaust system 190. The decomposition chamber 104 includes an inlet in fluid connection with the DPF 102 to receive the exhaust gas containing NOₓ. x -emissions, as well as an outlet for the exhaust gas, NO x -Emissions, ammonia and / or remaining reducing agent for flow to the SCR catalyst 106.

[0023] The decomposition chamber 104 includes the metering module 112 attached to the decomposition chamber 104, enabling the metering module 112 to dose the reducing agent into the exhaust gases flowing into the exhaust system 190. The metering module 112 may include an insulator 114 located between a section of the metering module 112 and the section of the decomposition chamber 104 to which the metering module 112 is mounted. The metering module 112 is fluidically coupled to one or more reducing agent sources 116. In some implementations, a pump 118 may be used to pressurize the reducing agent source 116 for supply to the metering module 112.

[0024] The dosing module 112 and the pump 118 are also electrically or communicatively coupled to a controller 120. The controller 120 is configured to control the dosing module 112 to dose reducing agent into the decomposition chamber 104. The controller 120 can also be configured to control the pump 118. The controller 120 can include a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc., or combinations thereof. The controller 120 can include a memory, which may include an electronic, optical, magnetic, or other data storage or transmission device capable of providing program instructions to a processor, ASIC, FPGA, etc.The memory can include a memory chip, an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), flash memory, or other suitable memory from which the controller can read 120 instructions. The instructions can contain code written in any suitable programming language.

[0025] In certain implementations, the controller 120 is structured in such a way that it performs certain operations, such as those described herein with regard to Fig. 5-6 described. In certain implementations, the controller 120 forms part of a processing subsystem that includes one or more computing devices with storage, processing, and communication hardware. The controller 120 can be a single device or a distributed device, and the functions of the controller 120 can be performed by hardware and / or as computer instructions on a non-volatile, computer-readable data storage medium.

[0026] In certain implementations, the controller 120 comprises one or more modules structured to functionally execute the controller 120's operations. In certain implementations, the controller 120 may include a controlled heating process module for performing the operation described in relation to... Fig. The description herein, including the modules, emphasizes the structural independence of the aspects of the controller 120 and illustrates a possible grouping of operations and responsibilities of the controller 120. Other groupings performing similar overall operations are to be considered included within the scope of this application. Modules may be implemented in hardware and / or as computer instructions on a non-volatile, computer-readable data storage medium, and modules may be distributed across different hardware or computer-based components. More detailed descriptions of specific embodiments of controller operations are included in the part relating to the Fig. 5 to 6 refers to.

[0027] Exemplary and non-limiting module implementation elements include sensors providing any value specified herein, sensors providing any value that is a precursor to any value specified herein, datalink and / or network hardware including communication chips, oscillating crystals, communication links, cables, twisted-pair wiring, coaxial wiring, shielded wiring, transmitters, receivers and / or transmitter-receivers, logic circuits, hard-wired logic circuits, reconfigurable logic circuits in a specific non-volatile state configured according to the module specification, actuators including at least one electrical, hydraulic or pneumatic actuator, solenoid, operational amplifier, analog controls (springs, filters, integrators, adders, dividers,(amplification elements) and / or digital controls.

[0028] The SCR catalyst 106 is configured to reduce NO x -to contribute to emissions by reducing NO x -Reduction process between ammonia and NO x The conversion of the exhaust gas into diatomic nitrogen, water and / or carbon dioxide is accelerated. The SCR catalyst 106 includes an inlet in fluid connection with the decomposition chamber 104, from which exhaust gas and reducing agent are received, and an outlet in fluid connection with one end of the exhaust system 190.

[0029] The exhaust system 190 can also contain an oxidation catalyst (e.g. a diesel oxidation catalyst (DOC)) in fluid connection with the exhaust system 190 (e.g. downstream of the SCR catalyst 106 or upstream of the DPF 102) to oxidize hydrocarbons and carbon monoxide in the exhaust gas.

[0030] In some configurations, the DPF 102 can be positioned downstream of the decomposition chamber or the reactor tube 104. For example, the DPF 102 and the SCR catalyst 106 can be combined in a single unit, such as a DPF with SDPF coating (SDPF). In some implementations, the metering module 112 can instead be positioned downstream of or upstream of a turbocharger.

[0031] The sensor 150 can be coupled to the exhaust system 190 to detect the condition of the exhaust gas flowing through the exhaust system 190. In some implementations, the sensor 150 may have a portion located within the exhaust system 190; for example, a tip of the sensor 150 may extend into a part of the exhaust system 190. In other implementations, the sensor 150 may receive exhaust gas through a different conduit, such as a sample tube extending from the exhaust system 190. While the sensor 150 is shown to be positioned downstream of the SCR catalyst 106, it is understood that the sensor 150 can be positioned at any other position in the exhaust system 190, including upstream of the DPF 102, in the DPF 102, between the DPF 102 and the decomposition chamber 104, within the decomposition chamber 104, between the decomposition chamber 104 and the SCR catalyst 106, in the SCR catalyst 106 or downstream of the SCR catalyst 106.Additionally, two or more sensors 150 can be used to detect a condition of the exhaust gas, such as two, three, four, five or six sensors 150, with each sensor 150 being located at one of the previously mentioned positions of the exhaust system 190. III. Implementation example of sensor temperature estimation

[0032] In some implementations, determining or estimating the temperature of a sensor and / or a sensor component during engine and / or exhaust system operation can be used. For example, the temperature of the sensor and / or a component thereof can be used for controlled heating and / or cooling of the sensor and / or component to reduce the likelihood of a temperature shock. A temperature shock can occur due to dew formation on and / or within the sensor and / or sensor component. This dew can occur when the engine and / or exhaust system is initially started, when the sensor and / or sensor component has a reduced temperature relative to the exhaust gas temperature. The dew can form on and / or within the sensor and / or a sensor component (e.g.,Condensation may form on the sensor tip due to the reduced temperature relative to the exhaust gas and / or other components within the exhaust system. Furthermore, the sensor and / or its component can be positioned within a collection device, such as an exhaust gas sampling tube, which further reduces the rate at which the temperature of the sensor and / or its component rises relative to the exhaust gas. Rapid temperature changes in the sensor and / or its component, such as those caused by dew formation and / or rapid heating or cooling, can result in thermal shock, potentially damaging the sensor and / or its component.

[0033] A controller can operate a heater to increase the temperature of the sensor and / or an associated component. The heater can be located inside the sensor. The controller can operate the heater to raise the temperature of the sensor and / or associated components exposed to exhaust gas in the exhaust system in a controlled manner, thus reducing instances of temperature shock. That is, the controller can operate the sensor heater to raise the temperature of the sensor and / or associated components to a predetermined or operating temperature to reduce dew formation and / or evaporate dew. In some implementations, the heater control can be based on the temperature of the sensor and / or an associated component.The temperature, such as a peak temperature, can be used by the controller to estimate whether the sensor and / or its associated components are above or below a threshold dew point value, in order to control a dew point heating strategy for the sensor. That is, if the temperature of the sensor and / or its associated components is below a predefined threshold, a controlled heating process can be initiated to reduce dew formation or to eliminate any dew that may have formed on or within the sensor and / or its associated components. If the temperature of the sensor and / or its associated components is at or above the predefined threshold, the controlled heating process will likely not be carried out.

[0034] In some cases, two or more predefined thresholds can be used. A first predefined threshold can correspond to an initial transition point, and a second predefined threshold can correspond to a second transition point. The initial transition point can be chosen based on a lower temperature at which dew is unlikely to form but can account for potential temperature estimation errors. The second transition point can be chosen based on a higher temperature at which dew is unlikely to form and which is sufficiently high that potential temperature estimation errors would still result in a temperature high enough that dew is unlikely to form.

[0035] Increasing the accuracy of a temperature determination or estimation for the sensor and / or its associated component can reduce the likelihood of a thermal shock. Accordingly, this document describes implementations for using a physically based determination and / or estimation of the temperature of the sensor and / or a component thereof, such as a sensor tip. The physically based determination can utilize additional exhaust gas flow parameters and / or component parameters to enhance the accuracy of the tip temperature determination or estimation.

[0036] Fig. Figure 2 shows a section of an implementation of an exhaust system 200 with a component 202, such as an SCR catalyst, located within a housing 204 and upstream of a sensor assembly 210. The sensor assembly 210 includes a sensor 220 positioned within a sample probe assembly of the sensor assembly 210. In some implementations, the sensor 220 may be positioned within the exhaust system without the sample probe assembly. The sensor 220 can measure NO x The sensor may include a CO sensor, an NH3 sensor, an O2 sensor, a particulate matter sensor, etc. In some implementations, the sensor 220 may include a sensor tip or other component that can be affected by temperature shock. The sensor 220 is configured to measure a quantity and / or detect the presence of a component of the exhaust gas of interest, such as NO. xCO, particles, NH3, etc. The sensor probe arrangement can be excluded in some implementations, e.g., if the sensor 220 is mounted on a side wall of the exhaust system 200. In other implementations, various sensor probe arrangements can be used with the sensor 220.

[0037] Fig. Figure 3 shows an implementation of the sensor arrangement 210 without the sensor 220. As can be seen, the sample probe arrangement of the sensor arrangement 210 includes at least two sample arms that are coupled to each other at a central section and extend radially outward from the central section to an outer end. The outer end can each be coupled to a cover, which may be arc-shaped. The cover can be attached to an inner surface of the housing 204. Fig. 2 be attached, which defines a fluid line of the exhaust system into which the sensor arrangement 210 is installed.

[0038] Each sample arm can be defined either as an individual flow arm or as a combined flow sample arm. Generally, sample fractions of the detected fluid entering the individual sample arms flow into sample fractions and combine with sample fractions entering and flowing through the combined flow sample arm. The sample probe arrangement of the sensor arrangement 210 comprises a combined flow sample arm and three individual flow sample arms, the four arms being spaced at equal angles to one another. In other embodiments, however, the sample probe arrangement of the sensor arrangement 210 may include fewer or more than four arms, the arms being spaced at equal angles to one another or having different angular distances between the arms.

[0039] The sample arms are hollow and each contains a fluid flow channel formed within them. The fluid flow channel of each sample arm can have various cross-sectional shapes, such as circular, elliptical, triangular, polygonal, and the like. Each sample arm includes a set of inlet openings through which a sample fraction of a main fluid stream is captured and directed into the fluid flow channels of the sample arms. The inlet openings can be configured in upstream surfaces of the sample arms such that each inlet opening points in an upstream direction (i.e., perpendicular to a fluid flow direction). In other words, the central axes of the inlet openings are essentially parallel to the fluid flow direction.In alternative embodiments, however, the inlet openings can also be angled into the side surfaces (or top and bottom surfaces) of the specimen arms, as well as into other locations / orientations deemed suitable that are not perpendicular to them. For example, in such alternative embodiments, the openings point in the direction of the angled flow relative to the fluid flow direction. In other words, the central axes of the angled inlet openings are not essentially parallel to the fluid flow direction.

[0040] Furthermore, the inlet openings of each sample arm are oriented radially along the arm, from a position near a central section of the sample arm to a position near or adjacent to the radially outer end of the sample arm. In the illustrated embodiment, each individual flow sample arm includes four inlet openings, while the overall sample arm includes a single inlet opening. In other embodiments, however, each sample arm may have fewer or more inlet openings. As shown, the inlet openings are essentially circular. In other embodiments, however, the inlet openings may have other shapes, such as polygonal, elliptical, rectangular, triangular, and the like.

[0041] The probe assembly of the sensor assembly 210 further includes a sensor shaft located at the outer end of the overall flow probe arm. The sensor shaft is a blunt, rounded body that encloses an internal volume in fluid communication with the fluid flow channel formed in the overall flow probe arm. The sensor shaft includes an outer section that opens to an inner surface of the fluid line or housing in which the sensor 220 is installed. The sensor shaft may include a front section with a blunt, rounded surface for deflecting the fluid flowing through the fluid line around the sensor shaft.

[0042] The sensor arrangement 210 is installed within the fluid line or the housing 204 such that the fluid flowing through the line either flows between the sample arms as the main fluid flow or into the inlet openings and through the inner passages of the sample probe arrangement of the sensor arrangement 210 as a sample component of the fluid flow to the sensor 220. Fig. Figure 4 represents a flow velocity profile 300 of an exemplary exhaust gas flow past the sensor arrangement 210 inside the housing 204 and inside the sensor arrangement 210.

[0043] Fig. Figure 5 is a process diagram of an implementation of Procedure 500 for determining the temperature of a sensor or a sensor component. Procedure 500 includes the steps of accessing parameters indicating exhaust mass flow, outlet temperature, ambient air temperature, and ambient air velocity (Block 510), and calculating the temperature of the sensor or sensor component (Block 520). In some implementations, a key switch parameter may be used as an activation condition for the execution of Procedure 500. That is, if a parameter indicating a key-on or key-switch-on event is set to 1, Procedure 500 may proceed. If the parameter indicating a key-on or key-switch-on event is set to 0 or a value other than 1, Procedure 500 terminates or is not executed.

[0044] Accessing parameters indicating exhaust gas mass flow, outlet temperature, ambient air temperature and ambient air velocity (block 510) may involve accessing a parameter value from a memory and / or other storage device, receiving a value from a sensor for the corresponding parameter, etc.

[0045] Calculating the temperature of the sensor or a sensor component (block 520) uses the called parameters, which indicate the exhaust mass flow rate, outlet temperature, ambient air temperature, and ambient air velocity, to determine an estimated temperature of the sensor or sensor component. In some implementations, a first thermal model can be selected if the exhaust mass flow rate (i.e., the exhaust mass flow velocity) is above a predefined threshold, and a second thermal model if the exhaust mass flow rate is below the predefined threshold. The predefined threshold can be an exhaust mass flow rate at an engine idle speed (i.e., the exhaust mass flow rate when an engine connected to the exhaust system is idling).If the exhaust gas mass flow rate exceeds the specified threshold, the heating of the sensor or sensor component can be based on convective heat transfer from the flowing exhaust gas to the sensor or sensor component. If the exhaust gas mass flow rate is below the specified threshold, the heating of the sensor or sensor component can be based on conductive heat transfer from an exhaust pipe of the exhaust system to the sensor or sensor component. The first thermal model for the temperature of the sensor or a sensor component, such as the sensor tip, can include the following:

[0046] Heat output from the exhaust gas stream: m˙Current_Sensor×[Cp−incurrent×Tin−Cp−outflow×Toff]

[0047] Heat output that is lost / gained from / to the sensor mass mSensor×Cp−Sensor×T˙Sensor.

[0048] Radiation power (to the environment) [TSensor4−TEnvironment4]×SurfaceSensor×5.6697×10−8×Emissivity.

[0049] Convection power (towards the environment) [TSensor−TEnvironment]×f(vAir).

[0050] Using the above, an energy balance for a sensor tip can be set as m˙Current_Sensor×[Cp−incurrent×Tin−Cp−outflow×Toff] even mSensor×Cp−Sensor×T˙Sensor+[TSensor4−TUmgebung4]×Oberfla¨cheSensor×5,6697×10−8×Emissionsvermögen +[TSensor−TUmgebung]×f(VLuft) assuming that T ein +T aus =2*T Sensor To solve the above, the outlet temperature, T, must be determined. aus , can be set. Then, using the parameters called up (from block 510), the sensor temperature, T, can be set. Sensor, can be calculated. The calculated temperature can then be used to control one or more processes, such as activating a controlled heating process for the sensor. According to the above model, it is assumed that T Spitze = (T SCR_aus +T Spitze_aus ) / 2, if the engine speed is greater than idle, where convection is the dominant heat transfer mode.

[0051] The second thermal model for the temperature of the sensor or a component of the sensor, such as the sensor tip, may include the following:

[0052] Heat output from the exhaust gas stream: m˙Exhaust_current×[Cp−inflow×Tin−Cp−outflow×Tout].

[0053] Heat output that is lost / gained from / to the exhaust pipe mass mPipe×Cp−Pipe×T˙Pipe.

[0054] Radiation power (to the environment) [TTube4−TTube4]×SurfaceTube×5.6697×10−8×Emissivity.

[0055] Convection power (towards the environment) [TRohr−TUmgebung]×f(vLuft).

[0056] Using the above, an energy balance for an exhaust pipe can be set up as follows: m˙Exhaust_current×[Cp−inflow×Tin−Cp−outflow×Tout]. even mPipe×Cp−Pipe×T˙Pipe+[TRout4−TEnvironment4]×SurfacePipe×5,6697×10−8×EmissionPotential+ [TRout−TEnvironment]×f(VAir). assuming that T ein +T aus =2*T Rohr To solve the above, the outlet temperature, T, must be determined. aus , can be set. Then, using the parameters called (from block 510), the temperature of sensor T can be determined. Sensor , equal to the temperature of the exhaust pipe T RohrThe calculated temperature can then be used to control one or more processes, such as activating a controlled heating process for the sensor. According to the above model, it is assumed that T Rohr = (T SCR_aus +T Rohr_aus ) / 2 if the engine speed is equal to or less than idle speed, if conduction is the dominant heat transfer mode.

[0057] Fig. Section 6 describes a method 600 for activating a controlled heating process in response to the temperature of a sensor or a sensor component. The method 600 involves accessing parameters indicating an exhaust mass flow rate, outlet temperature, ambient air temperature, and ambient air velocity (block 610), calculating the temperature of the sensor or sensor component (block 620), comparing the calculated temperature to a threshold temperature (block 630), and activating or deactivating a controlled heating process in response to the calculated temperature relative to the threshold temperature (block 640). In some implementations, a key switch parameter may be used as the activation condition for initiating the method 600.This means that if a parameter indicating a key-on or key-switch-on event is set to 1, procedure 600 can continue. If the parameter indicating a key-on or key-switch-on event is set to 0 or a non-1 value, procedure 600 terminates or is not executed.

[0058] Accessing parameters indicating exhaust gas mass flow, outlet temperature, ambient air temperature and ambient air velocity (block 610) may involve accessing a parameter value from a memory and / or other storage device, receiving a value from a sensor for the corresponding parameter, etc.

[0059] Calculating the temperature of the sensor or a sensor component (Block 620) uses the parameters listed, which indicate the exhaust mass flow, outlet temperature, ambient air temperature, and ambient air velocity, to determine an estimated temperature of the sensor or sensor component. The calculated temperature can be used to determine the above with respect to Fig. Use the thermal model described in section 5.

[0060] Procedure 600 further includes comparing the calculated temperature with a threshold temperature (Block 630). If the calculated temperature of the sensor and / or associated component is below a predetermined threshold, a controlled heating process may be performed to eliminate any dew that may have formed on or inside the sensor and / or associated component. If the temperature of the sensor and / or associated component is at or above the predetermined threshold, the controlled heating process must not be performed. The predetermined temperature threshold may be between 130°C and 160°C, between 140°C and 150°C, or between 140°C and 150°C. In some cases, two or more predetermined thresholds may be used.A first predefined threshold can correspond to an initial transition point, and a second predefined threshold can correspond to a second transition point. The initial transition point can be chosen based on a lower temperature at which dew is unlikely to form, but can account for potential temperature estimation errors. The second transition point can be chosen based on a higher temperature at which dew is unlikely to form and is sufficiently high so that potential temperature estimation errors would still result in a temperature high enough that dew is unlikely to form.In some implementations, the initial transition point can be in a range of 130°C to 150°C, for example, 140°C, and the second transition point can be in a range of 140°C to 160°C, for example, 150°C. In some implementations, a flag value can also be monitored with the initial transition point threshold, so that if the calculated temperature is higher than the initial transition point temperature and the flag indicates that the controlled heating process from a previous iteration is being deactivated, the flag value can remain at the same value. If the flag indicates that the controlled heating process from a previous iteration is being activated, the flag value can also remain at the same value.

[0061] Procedure 600 also includes activating or deactivating a controlled heating process in response to the calculated temperature relative to the threshold temperature (Block 640). If the calculated temperature is above the threshold temperature, a controlled heating process can be activated. The controlled heating process can involve activating a sensor heater and / or an external heater to warm the sensor. Activating or deactivating the controlled heating process can involve changing the value of a control parameter, such as a 1 to deactivate the controlled heating process and a 0 to activate it.

[0062] Fig. Figure 7 shows an exemplary procedure 700 for tuning a calibration for the thermal model of procedure 500. Fig. 5 for calculating the temperature of a sensor or a sensor component. Procedure 700 involves setting constraints on physical parameters and adjustment elements (Block 710). The physical constraints can be properties of the material or component for the thermal model. The adjustment elements can be other parameters that can be modified for the thermal model. Some implementations of physical property constraints and adjustment elements include setting a sensor tip surface (m 2 ) of less than 1, a sensor peak mass of more than 0.05 kg and less than 1, a sensor length (m) of less than 2, C p of the sensor of more than 0.01 and less than 1 (kJ / kg*k), h of the sensor of more than 0.001 and less than 1 W / (m 2K), a sensor emissivity of more than 0.001 and less than 1, and a flow fraction of more than 0.001 and less than 0.01. Some other implementations of physical property constraints and adjustment elements may include adjusting an exhaust pipe surface area (m 2 ) of less than 1, a pipe mass of more than 0.05 kg and less than 1, a pipe length (m) of less than 2, C p of the exhaust pipe of more than 0.01 and less than 1 (kJ / kg*k), h of the exhaust pipe of more than 0.001 and less than 1 W / (m 2 K) and an exhaust emission level of more than 0.001 and less than 1.

[0063] The procedure involves generating a Latin hypercube set of calibrations (Block 720), optionally setting up parallel processors (Block 730), and simulating all calibrations (Block 740). The top calibrations (e.g., based on a mean squared error calculation) can be optimized (Block 750) to generate calibration values ​​for the thermal model parameters.

[0064] Fig. 8 represents a set of values ​​that can be determined for the temperature of a sensor tip using method 500 of Fig. 5 were calculated in relation to a measured temperature, and Fig. 9 represents values ​​for the control parameter as they relate to procedure 600 of Fig. 6 are described using the calculated temperature.

[0065] The term "controller" encompasses all types of equipment, devices, and machines for processing data, including, for example, a programmable processor, a computer, a system-on-a-chip (SoC), or several of these, a section of a programmed processor, or combinations thereof. The device may include a dedicated logic circuit, such as an FPGA or an ASIC. In addition to the hardware, the device may also include code that creates an execution environment for the computer program in question, such as code representing 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 the execution environment can implement various different computing model infrastructures, such as distributed computing and lattice computing infrastructures.

[0066] A computer program (also known as a program, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be used in any form, such 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).

[0067] Although this document contains many specific implementation details, these should not be interpreted as limitations on the scope of what can be claimed, but rather as descriptions of features specific to certain implementations. Certain features described in this patent specification in the context of separate implementations may also be implemented in combination within a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately in multiple implementations 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.

[0068] Similarly, while operations are depicted in the drawings in a particular order, this should not be interpreted as requiring these operations to be performed in that specific order or sequentially, or as requiring all illustrated operations to be performed to achieve desirable results. Under certain circumstances, the separation of different system components in the implementations described above cannot be understood as requiring such separation in all implementations, and it should be clear that the described components and systems may generally be integrated into a single product or embodied and packaged in multiple products on tangible media.

[0069] As used herein, the terms “approximately”, “about”, “essentially”, and similar terms are intended to have a broad meaning consistent with their conventional and customary use by those skilled in the art in the field of this disclosure. It is obvious to those skilled in the art reading this disclosure that these terms are intended to permit a description of certain described and claimed features without limiting the scope of those features to the precise numerical ranges provided. Accordingly, these terms are to be interpreted as indicating that inessential or minor modifications or alterations to the described and claimed subject matter are to be considered to be within the scope of the invention as set forth in the appended claims.Additionally, it is noted that limitations of the claims in the event that the term "means" is not used therein are not to be interpreted as "means plus function" limitations under US patent law.

[0070] The terms "coupled," "connected," and the like, as used herein, mean the direct or indirect connection of two components. This connection can be stationary (e.g., permanent) or movable (e.g., removable or detachable). This connection can be achieved by the two components, or the two components and any further intermediate components, being integrally formed as a single, unified body, or by the two components, or the two components and any further intermediate components, being attached to one another.

[0071] The terms “fluid-coupled” or “fluid-connected” and the like, as used herein, mean that the two components or objects have a path formed between them in which a fluid, such as water, air, gaseous reducing agent, gaseous ammonia, etc., can flow, either with or without intervening components or objects. Examples of fluid couplings or configurations for enabling fluid connection may include pipes, channels, or any other suitable components for allowing a fluid to flow from one component to the other.

[0072] It is important to note that the design and arrangement of the system shown in the various exemplary implementations are merely illustrative and not limiting. It is desired that all changes and modifications falling within the spirit and / or scope of the described implementations be protected. It is understood that some features are not necessary, and implementations lacking these features are considered to fall within the scope of the application, which is defined by the following claims. When reading the claims, it is understood that the use of words such as "a," "an," "at least a," or "at least a section" / "at least a part / section," and their declensions, does not intend to limit the claim to only one subject matter unless expressly stated otherwise in the claim.Where the terms “at least one section” / “at least one share / part” and / or “one section” / “one share / part” are used, the subject matter may include one section / one share / part and / or the entire subject matter, unless expressly stated otherwise.

Claims

[1] Method for controlled heating of a sensor (150; 220) of a post-treatment system (100), the method comprising: Accessing a multitude of parameters, the multitude of parameters including exhaust gas mass flow, outlet temperature, ambient air temperature and ambient air velocity; Calculating a temperature of the sensor (150; 220) based on a thermal model and the called plurality of parameters, wherein a first thermal model is selected when the exhaust mass flow is above a predetermined threshold, and a second thermal model when the exhaust mass flow is not above the predetermined threshold, wherein the predetermined threshold is an exhaust mass flow at an idle speed of an engine; Comparing the calculated temperature with a threshold temperature, where the threshold temperature is between 130 degrees Celsius and 160 degrees Celsius; and Activating a controlled heating process for the sensor (150; 220) in response to the calculated temperature being below the threshold temperature, wherein the controlled heating process includes activating a heater to heat the sensor (150; 220). [2] Method according to claim 1, wherein the threshold temperature is between 140 degrees Celsius and 150 degrees Celsius. [3] Method according to claim 1 or 2, wherein the first thermal model comprises a heat output from an exhaust gas stream in the aftertreatment system (100), a heat output to the sensor (150; 220), a radiative power to the environment and a convection power to the environment. [4] Method according to one of the preceding claims, wherein the second thermal model comprises a heat output from an exhaust gas stream in the aftertreatment system (100), a heat output to an exhaust pipe, a radiative power to the environment and a convection power to the environment. [5] Method according to any of the preceding claims, further comprising access to a key-to parameter as an activation condition. [6] Method according to any of the preceding claims, wherein the thermal model is based on a calibration process to determine one or more calibration values ​​for parameters of the thermal model. [7] System (100), comprising: a sensor (150; 220); a heater in thermal connection with the sensor (150; 220); and a controller in electrical connection with the sensor (150; 220) and the heater, wherein the controller is configured to: Access to a multitude of parameters, including exhaust gas mass flow, outlet temperature, ambient air temperature, and ambient air velocity; Calculating a temperature of the sensor (150; 220) based on a thermal model and the called plurality of parameters, wherein a first thermal model is selected when the exhaust mass flow is above a predetermined threshold, and a second thermal model when the exhaust mass flow is not above the predetermined threshold, wherein the predetermined threshold is an exhaust mass flow at an engine idle speed; Comparing the calculated temperature with a threshold temperature, where the threshold temperature is between 130 degrees Celsius and 160 degrees Celsius; and Activating a controlled heating process for the sensor (150; 220) in response to the calculated temperature being below the threshold temperature, wherein the controlled heating process includes activating the heater to heat the sensor (150; 220). [8] System (100) according to claim 7, wherein the threshold temperature is between 140 degrees Celsius and 150 degrees Celsius. [9] System (100) according to claim 7 or 8, wherein the first thermal model comprises a heat output from an exhaust gas stream in an aftertreatment system, a heat output to the sensor (150; 220), a radiative output to the environment and a convection output to the environment. [10] System (100) according to one of claims 7 to 9, wherein the second thermal model comprises a heat output from an exhaust gas stream in an aftertreatment system (100), a heat output to an exhaust pipe, a radiant output to the environment and a convection output to the environment. [11] System (100) according to any one of claims 7 to 10, wherein the controller is further configured to call a key-on parameter as an activation condition. [12] System (100) according to any one of claims 7 to 11, wherein the thermal model is based on a calibration process to determine one or more calibration values ​​for parameters of the thermal model. [13] The method of claim 6, wherein the method comprises: Setting one or more restrictions for one or more physical parameters or tunable parameters of the post-treatment system (100); Generating a Latin Hypercube set of calibrations; Simulating each calibration of the generated Latin Hypercube set of calibrations; and Generating one or more calibration values ​​for the parameters of the thermal model based on the simulation. [14] Method according to claim 13, wherein the setting of the one or more constraints involves at least one of the setting of a sensor tip surface of less than 1 m². 2 , Setting a sensor peak mass of more than 0.05 kg and less than 1 kg, setting a sensor emissivity of more than 0.001 and less than 1, setting an emissivity of an exhaust pipe of the aftertreatment system (100) of more than 0.001 and less than 1 or setting an exhaust pipe surface area of ​​less than 1 m² 2 includes.

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