Method, software and open or closed loop apparatus for introducing heat into at least one component of an exhaust gas aftertreatment device

Abstract

The invention relates to a method for introducing heat into at least one component (11, 12, 13) of an exhaust gas aftertreatment device (1) of an internal combustion engine (15), in which method a partial flow of an exhaust gas flow is at least partially reacted with fuel in a thermal catalyst (2) and fed back to the exhaust gas flow, the amount of fuel fed to the thermal catalyst (2) and / or the partial flow fed to the thermal catalyst (2) being open-loop or closed-loop controlled as a function of the exhaust gas temperature (Tn, Tv) upstream and / or downstream of the component (11, 12, 13), and the amount of fuel fed to the thermal catalyst (2) and / or the partial flow fed to the thermal catalyst (2) being determined by means of at least one thermal catalyst characteristic map (35). The invention also relates to a data carrier having data stored thereon, a signal sequence representing data and being suitable for transmission via a computer network, and an open-loop or closed-loop control device for carrying out the method.

Description

Technical Field

[0001] This invention relates to a method for introducing heat into at least one component of an exhaust gas aftertreatment device for an internal combustion engine, wherein a portion of the exhaust gas stream reacts at least partially with fuel in a thermal catalytic converter and is fed back into the exhaust gas stream. The invention also relates to computer programs for performing such methods, as well as open-loop and closed-loop control devices. Background Technology

[0002] It is known in practice that at least one component is arranged in the exhaust gas line of an internal combustion engine to purify the engine's raw exhaust gas. This purification typically includes catalytic post-oxidation, particulate filtration, or catalytic reaction of nitrogen oxides with a reducing agent. In some cases, multiple components for different methodological steps of exhaust gas aftertreatment or purification may also be performed sequentially.

[0003] Because this component enables possible chemical reactions in the raw exhaust gas, it often requires a certain operating temperature, such as above 200°C or even above 300°C, to purify the raw exhaust gas efficiently. Although particulate filters can function even at room temperature, they require regeneration under certain loads, which is typically accomplished through the gaseous emission of oxidation and combustion products of the embedded particles at high temperatures.

[0004] Therefore, it is necessary to heat all or at least some components of the exhaust aftertreatment device by at least occasionally supplying thermal energy. This can be achieved, for example, through internal combustion engine measures, which, while adversely affecting the efficiency and / or pollutant emissions of the internal combustion engine, on the other hand, increase the exhaust gas temperature, thereby introducing additional heat into the components of the exhaust aftertreatment device.

[0005] WO 2020 / 193595 A1 further discloses the use of a thermal catalytic converter, to which a portion of the raw exhaust gas from an internal combustion engine is supplied. This portion of the raw exhaust gas reacts with fuel. In this process, heat is generated through an exothermic reaction independent of the operation of the internal combustion engine, and this heat can be fed to an exhaust gas aftertreatment device. Furthermore, this known thermal catalytic converter allows for the generation of easily ignitable syngas from the supplied fuel. This syngas can undergo an exothermic reaction on the exhaust gas catalytic converter, thereby directly generating heat within the catalytic converter.

[0006] However, this known device has the following drawbacks: during the dynamic operation of the internal combustion engine, especially in motor vehicles, the exhaust gas mass flow and its composition change. Because the heat released from the thermal catalytic converter into the components of the exhaust aftertreatment device depends non-linearly on the supplied exhaust gas volume, the supplied fuel volume, and the composition of the supplied exhaust gas, this results in large fluctuations in the heat emitted from the thermal catalytic converter. Furthermore, temperature control of the components of the exhaust aftertreatment device is complex due to the relatively long dwell time.

[0007] Based on existing technology, it is therefore necessary to control the introduction of heat into at least one component of the exhaust gas aftertreatment device more reliably through open-loop or closed-loop control, so as to prevent the exhaust gas aftertreatment device from cooling down and subsequently reducing emissions, and to avoid using unnecessary energy for heating. Summary of the Invention

[0008] According to the present invention, this objective is achieved by the method according to claim 1, the data carrier or signal sequence according to claim 12, and the open-loop or closed-loop control device according to claim 13, wherein the data carrier stores data, the signal sequence represents data, and is suitable for transmission via a computer network. Further advantageous embodiments of the invention can be found in the dependent claims.

[0009] According to the present invention, a method is provided for introducing heat into at least one component of an exhaust aftertreatment device for an internal combustion engine. In some embodiments of the invention, the internal combustion engine may be a spark-ignition internal combustion engine or a gasoline engine. In other embodiments of the invention, the internal combustion engine may be a compression-ignition internal combustion engine or a diesel engine. The internal combustion engine used according to the invention may be part of a motor vehicle, such as a bus or truck. In other embodiments of the invention, the internal combustion engine may be used in construction machinery or ships. In yet another embodiment of the invention, the internal combustion engine may also be used in a stationary generator or compressor. The advantages of the method according to the invention are particularly evident in dynamic operation, i.e., when the load requirements of the internal combustion engine change over short periods of time. This is, for example, the case with motor vehicles, especially in urban traffic.

[0010] Components of the exhaust aftertreatment device used according to the present invention may be, for example, a three-way catalytic converter. In other embodiments of the invention, the component may be selected from oxidation catalysts, storage catalysts, selective catalytic reduction (SCR) systems, and / or particulate filters. In some embodiments of the invention, multiple such components may also be present in the exhaust aftertreatment device and the raw exhaust gas from the internal combustion engine may flow through it in parallel or sequentially.

[0011] According to the invention, a portion of the exhaust gas flow from an internal combustion engine is proposed to react at least partially with fuel in a thermal catalytic converter, so that the products generated in the thermal catalytic converter are fed back into the exhaust gas flow. The resulting advantage is that the device for generating heat is largely independent of the internal combustion engine, thus the internal combustion engine does not have to operate under adverse operating conditions to generate additional heat. Instead, the internal combustion engine can always be operated in such a way that the required mechanical power is generated with the lowest possible pollutants and / or the lowest possible fuel consumption in each case.

[0012] The method according to the present invention aims to determine the exhaust gas temperature upstream and / or downstream of the components of the exhaust aftertreatment device used for introducing heat along the flow direction, and aims to control the heat discharged by the thermal catalytic converter based on this temperature in an open-loop or closed-loop control manner. In this context, the heat discharged by the thermal catalytic converter can be influenced by the mass flow rate of the portion of the original exhaust gas fed to the thermal catalytic converter, or the amount of fuel supplied, as reference variables. According to the invention, it is therefore proposed to adjust one or two influencing variables on the heat discharged per unit time by the thermal catalytic converter based on at least one exhaust gas temperature, such that the exhaust gas temperature upstream and / or downstream of the components remains constant at a predetermined desired value or within a predetermined fluctuation range. In some embodiments of the invention, the thermal catalytic converter may have other reference variables, such as ambient air supply or electric heating devices. These reference variables can be controlled in the same manner. In some embodiments of the invention, the fuel fed to the thermal catalytic converter is wholly or at least partially liquid.

[0013] The controlled desired exhaust gas temperature at at least one predetermined location in the exhaust aftertreatment device can vary during internal combustion engine operation. For example, if a differential pressure sensor detects excessive load on the particulate filter, the desired temperature upstream of the particulate filter can be temporarily increased, and the particulate filter should be regenerated by oxidative regeneration of the particles. Once the particulate filter has been regenerated, the desired exhaust gas temperature can then be reduced again, either over time or based on measurements. In other embodiments of the invention, such as when operating an oxidation catalyst or SCR system requiring a minimum operating temperature, the exhaust gas temperature can be controlled in a manner that prevents it from dropping below a specific minimum. If this minimum temperature is not reached, for example due to partial load operation of the internal combustion engine, additional heat can be introduced via a thermal catalyst used according to the invention.

[0014] In some embodiments of the invention, the exhaust gas temperature upstream and / or downstream of the components of the exhaust gas aftertreatment device can be detected by at least one temperature sensor. A thermocouple or resistance thermometer that generates an electrical signal corresponding to the temperature can be used as the temperature sensor in a manner known per se. Based on the measured variable of the exhaust gas temperature detected in this way, a reference variable of the thermal catalytic converter can then be influenced to control the control variable of the thermal power of the thermal catalytic converter through open-loop or closed-loop control.

[0015] In some embodiments of the invention, the exhaust gas temperature upstream and / or downstream of the components of the exhaust aftertreatment device can be determined by the operating state of the internal combustion engine. This feature allows for the elimination of additional sensor technology, thereby improving operational reliability. For example, the temperature generated at the catalytic converter or particulate filter can be calculated or tabulated based on the external temperature and the inflow velocity of the airflow, the heat power converted in the internal combustion engine, the proportion of that power dissipated into the exhaust gas, and the heat dissipation of the upstream exhaust gas line of the components. This allows for the establishment of thermal equilibrium for the components and the acquisition of subsequent temperatures without using temperature sensors in the exhaust gas flow.

[0016] In some embodiments of the present invention, the temperature of one portion of the exhaust gas can be measured and the temperature of another portion of the exhaust gas can be calculated. For example, the measured temperature downstream of the oxidation catalyst and the operating status of the internal combustion engine can be used to calculate the temperature upstream of the oxidation catalyst, or the measured temperature upstream of the oxidation catalyst and the operating status of the internal combustion engine can be used to calculate the temperature downstream of the oxidation catalyst. In other embodiments of the present invention, the inlet or outlet temperature of the SCR system located downstream of the oxidation catalyst can be determined by the temperature downstream of the oxidation catalyst.

[0017] In some embodiments of the invention, the operating state of the internal combustion engine used to determine the exhaust gas temperature can be determined by the currently applied characteristic map value or characteristic map range of the internal combustion engine control unit. Therefore, it is no longer necessary to measure, for example, the exhaust gas mass flow rate of the raw exhaust gas from the internal combustion engine. Instead, the exhaust gas mass flow rate can be determined with high accuracy from the intake air volume and the supplied fuel quantity. In some cases, other characteristic maps can be used to determine the operating state of the internal combustion engine more accurately, such as measurements from a λ probe, engine speed, accelerator pedal position, exhaust gas recirculation (AGR) valve position, coolant temperature, or other values ​​not explicitly mentioned herein.

[0018] The type of thermal catalytic converter used exhibits nonlinear heat dissipation behavior based on the amount of fuel supplied and / or a portion of the raw exhaust gas fed to the thermal catalytic converter. According to the invention, the amount of fuel supplied to the thermal catalytic converter and / or a portion of the raw exhaust gas fed to the thermal catalytic converter is determined by at least one thermal catalytic converter characteristic map. Input variables for the thermal catalytic converter characteristic map may, for example, be selected from the exhaust gas mass flow rate of the internal combustion engine and / or the oxygen content of the raw exhaust gas and / or at least one exhaust gas temperature and / or driving configuration and / or navigation destination and / or location data and / or at least one battery state of charge. Open-loop or closed-loop control via the thermal catalytic converter characteristic map has particular advantages here: even if the operation is highly dynamic, the control can be performed very quickly because only the expected values ​​of the reference variables currently applicable to the internal combustion engine operating conditions must be read from a conversion table stored in the control unit and set on the thermal catalytic converter.

[0019] In some embodiments of the invention, the exhaust gas mass flow rate of the internal combustion engine and / or the oxygen content of the raw exhaust gas and / or at least one exhaust gas temperature can be determined using a first reference control synthesizer. For the purposes of this invention, such a reference control synthesizer refers to a system that reconstructs unmeasurable variables from known input and output variables of the internal combustion engine. For this purpose, the synthesizer reproduces the internal combustion engine as a model and uses a controller to reconstruct measurable state variables, thus making it comparable to a real internal combustion engine. In this way, for example, the exhaust gas mass flow rate of the raw exhaust gas of the internal combustion engine can be calculated from the intake air mass and the amount of fuel supplied, without requiring significant technical effort to measure the exhaust gas mass flow rate, and without introducing errors that increase over operating time.

[0020] In some embodiments of the invention, the thermal power output by the thermal catalytic converter can be determined by a second reference control synthesizer from the amount of fuel supplied to the thermal catalytic converter and / or a portion of the raw exhaust gas from the internal combustion engine supplied to the thermal catalytic converter and / or the oxygen content in the raw exhaust gas. Therefore, an accurate measurement of the thermal power or heat introduced into the exhaust gas aftertreatment by the thermal catalytic converter is always available for temperature control without requiring significant technical effort to measure this thermal power.

[0021] In some embodiments of the method, the thermal catalytic converter may have at least a second operating state in which the air-to-fuel ratio λ of the thermal catalytic converter is between about 0.75 and about 30. In other embodiments of the method, the thermal catalytic converter may have at least a second operating state in which the air-to-fuel ratio λ of the thermal catalytic converter is between about 1.0 and about 10. This first operating state may also be referred to as combustor operation because the amount of fuel supplied in the thermal catalytic converter reacts largely or entirely with the residual oxygen in the original exhaust gas. In this first operating state, the thermal catalytic converter exhausts hot gas, which can be supplied via an exhaust gas line to an exhaust gas aftertreatment component and heated by directly introducing heat.

[0022] In some embodiments of the invention, the thermal catalytic converter may also have at least a fourth operating state in which the air ratio λ of the thermal catalytic converter is between about 0.05 and about 0.7. In this operating state, a portion of the fuel undergoes an exothermic reaction. The heat released by this exothermic reaction can be used to evaporate another portion of the supplied fuel and discharge that portion in gaseous form into the exhaust gas pipeline. Alternatively or additionally, the fuel may be converted into syngas by a chemical reaction on the thermal catalytic converter, which is also discharged into the exhaust gas pipeline. The syngas and / or fuel vapor may be oxidized at the exhaust gas catalytic converter, for example, at which it directly releases heat energy into the heated component of the exhaust gas aftertreatment device, such that the component is heated with lower heat loss and / or greater thermal power.

[0023] In some embodiments of the invention, the thermal catalytic converter may include at least one electric heating device in a first operating state to bring the thermal catalytic converter to an operating temperature at which supplied fuel can react at least partially on the thermal catalytic converter. This allows the thermal catalytic converter to reach operating temperature after a cold start.

[0024] In some embodiments of the invention, the thermal catalytic converter may include at least one electrically heated device for heating a portion of the raw exhaust gas supplied to the thermal catalytic converter in an eighth operating state. This embodiment allows heat to be introduced into at least one component of the exhaust aftertreatment device even when there is excess available electrical energy, such as when the internal combustion engine is in coasting mode and during recovery, even without a fuel supply. In some of these embodiments, the electrical power supplied to the thermal catalytic converter may depend on the state of charge of at least one battery, i.e., the thermal catalytic converter does not require electrical heating until no electrical energy as a charging current is needed or when location data and navigation destination from a travel prediction perspective allow for later battery charging. The battery may be selected from hybrid-drive high-voltage batteries and / or starter batteries.

[0025] In some embodiments of the invention, a portion of the raw exhaust gas from the internal combustion engine supplied to the thermal catalytic converter can be between about 3 kg / h and about 200 kg / h. In other embodiments of the invention, a portion of the raw exhaust gas from the internal combustion engine supplied to the thermal catalytic converter can be between about 3 kg / h and about 100 kg / h. In still other embodiments of the invention, this portion of the flow can be selected between about 6 kg / h and about 80 kg / h. In still other embodiments of the invention, this portion of the flow can be selected between about 6 kg / h and about 150 kg / h. This portion of the flow can be selected based on the oxygen content of the raw exhaust gas and / or based on the desired operating conditions of the thermal catalytic converter and / or based on the required thermal heating power.

[0026] The method proposed according to the invention can be implemented in a computer program that executes the method according to the invention when running on a microprocessor. This computer program can be available on a data carrier storing data, or in the form of a signal sequence representing data suitable for transmission over a computer network.

[0027] In some embodiments of the invention, the invention relates to an open-loop or closed-loop control device designed to perform the method according to the invention. For this purpose, the open-loop or closed-loop control device may have at least one microprocessor or a microcontroller. Furthermore, the open-loop or closed-loop control device may include a memory designed to receive computer programs. Additionally, the open-loop or closed-loop control device may include an analog or digital interface capable of processing sensor data, such as the oxygen content of the raw exhaust gas and / or the exhaust gas temperature upstream and / or downstream of components of the exhaust aftertreatment device. Finally, the open-loop or closed-loop control device may have a digital interface designed to receive data from the internal combustion engine control unit of the internal combustion engine to obtain the operating conditions of the thermal catalytic converter from the current operating state of the internal combustion engine. Attached Figure Description

[0028] The invention will now be explained in more detail based on the accompanying drawings and embodiments without limiting the general concept of the invention. In the drawings:

[0029] Figure 1 A first embodiment of an exhaust gas aftertreatment device that can be used according to the present invention is shown.

[0030] Figure 2 A second embodiment of an exhaust gas aftertreatment device that can be used according to the present invention is shown.

[0031] Figure 3 A block diagram of an open-loop or closed-loop control device according to the present invention is shown.

[0032] Figure 4 A structural diagram of the method according to a first embodiment of the present invention is shown.

[0033] Figure 5 A structural diagram of the method according to a second embodiment of the present invention is shown.

[0034] Figure 6 The use of the method according to the first embodiment of the present invention is illustrated.

[0035] Figure 7 The use of the method according to a second embodiment of the present invention is illustrated. Detailed Implementation

[0036] based on Figure 1A first embodiment of the exhaust aftertreatment device 1, which is applicable according to the present invention, is explained in more detail. The exhaust aftertreatment device 1 is connected to an internal combustion engine 15 via an exhaust gas line. The internal combustion engine 15 may be a compression ignition internal combustion engine of known design or a spark ignition internal combustion engine of known design. The internal combustion engine 15 draws in ambient air and causes the ambient air to react exothermically with the supplied fuel. In this process, the internal combustion engine 15 outputs mechanical energy. During the operation of the internal combustion engine 15, raw exhaust gas is generated, which may contain pollutants such as CH4 in addition to CO2 and H2O. X CO and / or NO X .

[0037] Raw exhaust gas is fed to exhaust gas aftertreatment unit 1 via an exhaust gas pipeline. Optionally, a sensor system may be installed in the exhaust gas pipeline; the sensor system may be, for example, a λ-probe for measuring the oxygen content of the raw exhaust gas. In the illustrated first embodiment, exhaust gas aftertreatment unit 1 includes a first SCR system 13a and a second SCR system 13b. Each SCR system is designed to catalytically reduce nitrogen oxides in the raw exhaust gas by adding a reducing agent. For this purpose, a temperature above 220°C, preferably above 250°C, is required.

[0038] The particulate filter 12 is located between the two SCR systems 13a and 13b along the flow direction. The particulate filter 12 is designed to retain fine dust or soot particles generated during the operation of the internal combustion engine 15. If the particulate filter 12 becomes clogged with increased use, it can be temporarily heated to a high temperature under oxygen supply, causing the embedded particles to be oxidized and discharged in gaseous form.

[0039] exist Figure 1 In the first embodiment shown, the first SCR system 13a and the particulate filter 12 are mounted close to the internal combustion engine, such that the thermal energy of the raw exhaust gas is sufficient to bring these components to or maintain their operating temperature. On the other hand, the second SCR system 13b is located further downstream of the exhaust gas line, such that the second SCR system 13b only slowly reaches its operating temperature and / or can be cooled to below its operating temperature during partial load operation of the internal combustion engine 15. Therefore, exhaust gas purification is insufficient during partial load operation, which is referred to as emission reduction in the sense of this specification.

[0040] To address this issue, a thermal catalytic converter 2 is located upstream of the second SCR system 13b. A portion of the raw exhaust gas flowing in the exhaust gas line is fed to the thermal catalytic converter 2. Additionally, fuel is supplied to the thermal catalytic converter, where it reacts with the exhaust gas or residual oxygen contained within it. The heat generated in this process is fed back to the exhaust gas line as hot gas and introduced into the second SCR system 13b. This additional heat introduction can occur after a cold start and during partial load operation, thus allowing for rapid heating on the one hand and preventing cooling during operation on the other. The thermal catalytic converter 2 can be shut off under full-load or near-full-load operating conditions of the internal combustion engine.

[0041] refer to Figure 2 A second embodiment of the exhaust gas aftertreatment device that can be used according to the invention is explained in more detail. The same reference numerals denote the same components of the invention; therefore, the following description is limited to essential differences. Figure 2 An oxidation catalyst 11 is shown, designed for the post-oxidation of oxidizable components in the raw waste gas, such as CO and / or CHx. As described above, a particulate filter 12 is located downstream of the oxidation catalyst. Specifically, an SCR system for NOx reduction is located downstream of the particulate filter 12.

[0042] In the illustrated embodiment, the thermal catalytic converter 2 is located upstream of the oxidation catalytic converter 11 and downstream of the internal combustion engine 15. Therefore, during operation, a portion of the previously unpurified raw exhaust gas from the internal combustion engine 15 is supplied to the thermal catalytic converter 2.

[0043] Figure 11 also shows three temperature sensors 111, 112, and 132. These temperature sensors measure the exhaust gas temperature at the inlet of the oxidation catalyst, the outlet of the oxidation catalyst, and the outlet of the SCR system. These three temperature sensors should be understood as merely exemplary. In other embodiments of the invention, the number of temperature sensors used may be more or fewer. In some cases, temperature sensors may not be used at all, as referenced above. Figure 1 In this case, the temperature can be determined by the operating state of the internal combustion engine, for example, using a reference control synthesizer.

[0044] It should be noted that, Figure 1 and Figure 2 The exhaust gas aftertreatment device 1 shown should be understood as merely exemplary. In other embodiments of the invention, other components may be used, such as a three-way catalytic converter or a storage catalytic converter. Similarly, individual components may be omitted. For the purposes of this invention, it is only important that at least one component 11, 12, 13 is present in the exhaust gas aftertreatment device 1.

[0045] The object of this invention is to rapidly reach the operating temperature of at least one component 11, 12, 13 and / or maintain at least one component 11, 12, 13 at a low exhaust gas temperature of the internal combustion engine 15, which is particularly likely to occur under lower partial load ranges. The exhaust gas temperatures upstream and / or downstream of the components can be as follows: Figure 2 The temperature is measured as shown, or determined by the operating state of the internal combustion engine. In the second case, for the purposes of this specification, the temperature is also referred to as the "measured value," even if the temperature is not directly measured, for example, by means of a thermocouple or resistance thermometer.

[0046] The measured temperature, its deviation from a predetermined expected value, the heat capacity of the exhaust gas pipeline and upstream components of the exhaust gas aftertreatment device, and the heat loss or gain of the raw exhaust gas during its passage through the aftertreatment device make the required thermal power of the thermal catalytic converter 2 a control variable. This control variable may be influenced by the amount of fuel supplied to the thermal catalytic converter 2 and the amount of exhaust gas supplied to it, and in some cases, by the electrical energy supplied to the thermal catalytic converter 2 as a reference variable. This reference variable, in turn, depends on the oxygen content of the raw exhaust gas from the internal combustion engine 15, the exhaust gas temperature, and the exhaust gas mass flow rate. Therefore, Figure 3 The embodiment of the open-loop or closed-loop control device 3 shown uses a thermal catalytic converter characteristic curve 35. Data from the internal combustion engine control unit 16, including the temperature and oxygen content of the raw exhaust gas measured or determined via a first reference control synthesizer, is provided to the thermal catalytic converter characteristic curve 35. Similarly, measurements optionally read from the internal combustion engine control unit 16 are fed to the open-loop or closed-loop control device 3 via a digital data link 351. Thereafter, the open-loop or closed-loop control device 3 can read and set reference variables using the thermal catalytic converter characteristic curve 35.

[0047] In some embodiments of the invention, in addition to data from the motor control unit 16, other data can be provided to the open-loop or closed-loop control device 3. The open-loop or closed-loop control device 3, under the control of the catalytic converter characteristic map or through calculation, can then control the various reference variables of the catalytic converter 2 more quickly or accurately. This other data can be selected from driving profiles and / or navigation destinations and / or location data and / or battery charging status. For example, if it is known that the vehicle is about to go uphill and a larger and hotter exhaust gas mass flow rate from the internal combustion engine can be obtained as a result, the heating power of the catalytic converter 2 can be proactively reduced earlier. Similarly, the catalytic converter can be proactively activated earlier at the end of a slope to prevent or reduce the temperature drop of components in the exhaust aftertreatment device, since the internal combustion engine operates only under partial load or even coasting mode when driving downhill. In the same way, location data can be used to define the basic load range of the catalytic converter 2, because, for example, in urban areas, the average load of the internal combustion engine 15 can be expected to be lower than during highway driving. Similarly, vehicle operation in urban areas can indicate a higher dynamic range, while intercity travel places a more uniform load demand on the internal combustion engine 15. Finally, the navigation destination can also be used to control the thermal catalytic converter 2, for example by stopping the regeneration of the particulate filter 12 shortly before reaching the destination or by delaying the regeneration of the particulate filter 12 until the vehicle reaches the city boundary.

[0048] Figure 4 A structural diagram of a first embodiment of the method according to the invention is shown. In the first embodiment, the thermal catalyst 2 can operate in seven different operating states, which are indicated by reference numerals 51 to 57. Figure 4 The process control should not be interpreted as meaning that these seven operating states must be performed sequentially. Instead, downstream of the oxidation catalyst, at least one temperature is determined directly or indirectly from the operating state of the internal combustion engine. Then, based on the temperature and other optional parameters, such as the engine's operating time, one of the indicated operating states of the thermal catalyst 2 is selected. If the temperature at the oxidation catalyst outlet changes, making the applied operating state unsuitable, the open-loop or closed-loop control device changes to another operating state based on the temperature. In this case, hysteresis can be used to avoid frequent changes in the operating state of the thermal catalyst 2. The individual operating states are explained in more detail below.

[0049] The first operating state 51 indicates the start of the thermal catalytic converter. For this purpose, the thermal catalytic converter can be preheated by initially supplying exhaust gas mass flow with optional electric heating equipment until the supplied fuel undergoes exothermic conversion on the thermal catalytic converter and further heats the thermal catalytic converter to its operating temperature.

[0050] In a second operating state 52, a relatively large exhaust gas mass flow rate, for example, from about 60 kg / h to about 100 kg / h, is supplied to the thermal catalytic converter. The thermal catalytic converter operates at an air ratio λ between about 0.75 and about 3.5 or between about 1.5 and about 2.5. This results in almost complete conversion of the supplied fuel with the residual oxygen in the exhaust gas supplied to the thermal catalytic converter 2. In some embodiments, the thermal catalytic converter can deliver thermal power from about 5 kW to about 20 kW in the form of hot gas.

[0051] The third operating state 53 represents alternating operation, in which a cyclical switching occurs between the first sub-step 53a and the second sub-step 53b. In the first sub-step 53a, the operating conditions roughly correspond to the operation in the second method step 52. In the second sub-step 53b, the exhaust gas mass flow rate is reduced by 10 to 25 times, for example, reduced to about 3 kg / h to about 10 kg / h, causing the thermal catalyst to operate at an air ratio λ between about 0.05 and about 0.5 or between about 0.1 and about 0.4. Therefore, in the second sub-step 53b, the supplied fuel does not react completely, but is partially evaporated and partially converted into syngas, which is supplied to the oxidation catalyst through the exhaust gas line. The heat supplied in the first sub-step 53a allows the syngas to be ignited at the oxidation catalyst, where the syngas can be exothermically converted, resulting in the direct release of heating power of about 13 kW to about 20 kW at the oxidation catalyst.

[0052] The fourth method step 54 is similar to the second sub-step 53b of the third method step 53. However, the exhaust gas flow rate supplied to the thermal catalytic converter is larger and can be between about 5 kg / h and about 20 kg / h. This control allows a predetermined proportion of the raw exhaust gas to pass through the thermal catalytic converter. For example, about 2% to about 10% or about 3% to about 8% of the internal combustion engine exhaust gas flow can be fed as a partial flow to the thermal catalytic converter 2. In the fourth operating state 54, the thermal catalytic converter can supply about 10 kW to about 50 kW or about 14 kW to about 36 kW of thermal power to the oxidation catalytic converter 11 in the form of combustible syngas. Therefore, the fourth operating state 54 is particularly suitable for rapidly heating the exhaust gas aftertreatment device after a cold start and after the thermal catalytic converter has been started in the first method step 51 and some pretreatment of the exhaust gas aftertreatment device has been performed in the second process step 52 and the third process step 53.

[0053] After the exhaust gas aftertreatment device is heated to a predetermined desired temperature, the thermal catalytic converter 2a can be cleaned in the fifth method step 55. For this purpose, a portion of the supply flow is increased again, for example, to about 50 kg / h to about 100 kg / h. Compared to the second method step 52, the amount of fuel supplied can be reduced, so that the heat released in the thermal catalytic converter 2 is mainly used for oxidizing and vaporizing the remaining deposits and residual fuel to prevent permanent deposits and contamination in the thermal catalytic converter 2.

[0054] Step 56 of the sixth method applies to heat preservation operation, for example, if the internal combustion engine 15 only produces low exhaust gas temperatures within a lower partial load range or if no fuel is supplied to the internal combustion engine during coasting operation. In step 56 of the sixth method, the thermal power of the catalytic converter can be between about 0 kW and about 10 kW. For this purpose, a relatively low portion of the original exhaust gas flow of about 5 kg / h to about 50 kg / h is supplied to the catalytic converter 2, while the catalytic converter operates at an air ratio λ between about 0.75 and about 3.5 or between about 1.5 and about 2.5.

[0055] If it is not necessary for the thermal catalytic converter 2 to be kept at a high exhaust gas temperature, the thermal catalytic converter 2 can also be turned off in step 57 of the seventh method. In this case, no fuel is fed to the thermal catalytic converter 2, so that the thermal catalytic converter does not emit any heat, even if a portion of the exhaust gas flows through the thermal catalytic converter 2 due to its installation condition.

[0056] In some embodiments of the invention, method steps 51, 52, 53, and 54 are performed cyclically after a cold start, and in each case, the system switches to the next operating state when a predetermined temperature threshold is reached. Then, during continuous operation of the internal combustion engine, the system can switch between operating states 54, 55, 56, and 57 based on the deviation between the desired and actual temperatures of the exhaust gas temperature or the oxidation catalyst. A hysteresis can be set between the temperature limits of each operating state to avoid frequent and undesirable changes in the operating state.

[0057] refer to Figure 5 The following provides a more detailed structural diagram of a second embodiment of the method according to the invention. Identical components or operating states of the invention are designated by the same reference numerals, such that the following description is limited to essential differences. In step 51 of the first method, after a cold start of the internal combustion engine or a vehicle equipped with the internal combustion engine, the thermal catalytic converter is activated.

[0058] Once the thermal catalytic converter 2 has reached its operating conditions, the open-loop or closed-loop control device checks whether the exhaust gas temperatures upstream and downstream of the oxidation catalytic converter 11 are above predetermined limits and whether the exhaust gas mass flow rate exceeds a predetermined minimum. If this is the case, a fourth operating state with relatively low partial flow and low air ratio can be started immediately, allowing for rapid heating of the oxidation catalytic converter. If this is not the case, the components of the exhaust gas aftertreatment device are first preheated in catalytic burner mode according to the second operating state 52.

[0059] Once the thermal front generated in step 54 of the fourth method has penetrated all components of the exhaust gas aftertreatment device, and the temperature sensor 132 at the output of the SCR system also detects a value higher than a predetermined limit, the thermal catalyst 2 switches to heat preservation operation according to the sixth operating state 56 described above.

[0060] according to Figure 5 The main difference between this process control and previous control methods lies in that the open-loop or closed-loop control device 3 of the thermal catalytic converter 2 reads operating data from the internal combustion engine control unit 16 of the internal combustion engine 15, and, if necessary, uses other data such as remaining driving distance, terrain, and road grade to determine the required thermal power of the thermal catalytic converter 2 in advance. Based on the current and / or future operating conditions of the internal combustion engine, it uses the thermal catalytic converter characteristic diagram 35 to set the optimized values ​​for the partial flow and fuel quantity of the thermal catalytic converter 2. In this way, the lag time of the control circuit can be eliminated, allowing the desired value of the exhaust gas aftertreatment component temperature to be reached more quickly or with less fluctuation in the actual temperature.

[0061] Figure 6 The method according to the invention is shown in accordance with Figure 4 The first embodiment of the multi-level control system is used. Figure 6 a) Shows the mass flow rate of the raw exhaust gas on the left vertical axis (represented by curve A) and the oxygen content of the exhaust gas on the right vertical axis (represented by curve B) in seconds. Figure 6 b) shows the temperature of the temperature sensor 12 located downstream of the oxidation catalyst 11, represented by curve C on the right ordinate, and the output power of the thermal catalyst, represented by curve D on the left ordinate, on the same time axis. Figure 6 b) shows the measured values ​​relative to the expected value of 400°C. Figure 6 c) shows the comparison with Figure 6 b) Similar measurements, but these measurements are relative to the expected value of 280°C.

[0062] from Figure 6 As can be seen, in the section shown in the WHTC cycle, the output power of the internal combustion engine 15 is not constant over time, but highly dynamic. Consequently, the exhaust gas mass flow rate and oxygen content also change within seconds. Figure 6 As shown in both b) and 6c), the thermal catalytic converter 2 can be controlled very quickly using the open-loop or closed-loop control device according to the invention, such that the heat introduced by the thermal catalytic converter largely compensates for the fluctuating heat introduced by the internal combustion engine, so that the output temperature downstream of the oxidation catalytic converter 11 fluctuates only to a small extent. Therefore, the oxidation catalytic converter 11 can always be used, even when the internal combustion engine is operating at partial load. No emission reduction occurs.

[0063] Figure 7 The use of the method according to the invention in a second embodiment, namely the regeneration of the particulate filter 12, is described. Figure 7 a) Curve A shows the exhaust gas mass flow rate. Figure 7 b) Curve F shows the exhaust gas temperature downstream of the internal combustion engine. Curve C shows the temperature at the outlet of the oxidation catalyst or the inlet of the particulate filter. Figure 7 c) Curve E shows the CO content in the original exhaust gas, and curve G shows the CHx content.

[0064] For the regeneration of the particulate filter 12, a high exhaust gas temperature is required to oxidize the embedded particles and discharge them from the particulate filter 12 in gaseous form. According to existing technology, this is achieved by increasing the exhaust gas temperature through internal combustion engine measures, which results in unsatisfactory consumption and emission values ​​during the regeneration process.

[0065] like Figure 7 As shown, activating the thermal catalytic converter 2 after approximately 60 seconds causes the exhaust gas temperature to rapidly rise from about 200°C to about 600°C. Although the dynamic load demands on the internal combustion engine and the exhaust gas mass flow rate fluctuate accordingly over time, the exhaust gas temperature is maintained constant within a narrow temperature range by the thermal catalytic converter. As indicated by curves E, F, and G, regeneration does not require further internal combustion engine measures, meaning the raw exhaust gas temperature remains consistently below 250°C. Similarly, pollutant emissions, represented by curves E and G, do not increase during the regeneration of the particulate filter, unlike existing technologies.

[0066] Of course, the present invention is not limited to the embodiments shown. Therefore, the above description should not be considered limiting, but rather interpretative. The appended claims should be understood to mean that the stated features exist in at least one embodiment of the invention. This does not preclude the existence of more features. Where the "first" and "second" embodiments are defined in the claims and the above description, the names are used to distinguish two similar embodiments rather than to determine an order of arrangement.

Claims

1. A method for introducing heat into at least one component (11, 12, 13) of an exhaust gas aftertreatment device (1) of an internal combustion engine (15), in which method a partial flow of the exhaust gas flow of the internal combustion engine is at least partially reacted with fuel in a thermal catalyst (2) to feed back products produced in the thermal catalyst (2) to the exhaust gas flow, characterized in that, The amount of fuel fed to the thermal catalyst (2) and / or the partial flow fed to the thermal catalyst (2) is open-loop or closed-loop controlled depending on the exhaust gas temperature upstream and / or downstream of the component (11, 12, 13), and the amount of fuel fed to the thermal catalyst (2) and / or the partial flow fed to the thermal catalyst (2) is determined by at least one thermal catalyst map (35); wherein the input variables (351) of the thermal catalyst map (35) are selected from the exhaust gas mass flow of the internal combustion engine and / or the oxygen content of the raw exhaust gas of the internal combustion engine and / or at least one exhaust gas temperature and / or a driving configuration and / or a navigation destination and / or position data and / or a state of charge of at least one battery; wherein the exhaust gas mass flow of the internal combustion engine (15) and / or the oxygen content of the raw exhaust gas of the internal combustion engine and / or at least one exhaust gas temperature is determined by a first reference control synthesizer.

2. The method of claim 1, wherein, The exhaust gas temperature upstream and / or downstream of the component (11, 12, 13) is detected using at least one temperature sensor (111, 112, 132).

3. The method of claim 1, wherein, The exhaust gas temperature upstream and / or downstream of the component (11, 12, 13) is determined by an operating state of the internal combustion engine (15).

4. The method of claim 3, wherein, The operating state of the internal combustion engine is determined by a currently applied map value or map range of an internal combustion engine control unit (16).

5. The method of claim 1, wherein, The amount of fuel fed to the thermal catalyst (2) and / or the partial flow fed to the thermal catalyst (2) is open-loop or closed-loop controlled depending on the exhaust gas temperature upstream and / or downstream of the component (11, 12, 13), and the amount of fuel fed to the thermal catalyst (2) and / or the partial flow fed to the thermal catalyst (2) is determined by at least one thermal catalyst map (35); 6. The method of claim 1, wherein, The thermal catalyst (2) has at least a second operating state (52), wherein the air ratio lambda of the thermal catalyst (2) is between 0.75 and 30, or between 1.0 and 10, and The thermal catalyst (2) has at least a fourth operating state (54), wherein the air ratio lambda of the thermal catalyst (2) is between 0.05 and 0.

7.

7. The method of claim 1, wherein, The partial flow is between 3 kg / h and 100 kg / h or between 6 kg / h and 80 kg / h.

8. The method of claim 1, wherein, The thermal catalyst (2) comprises at least one electric heating device which, in a first operating state, serves to bring the thermal catalyst (2) to an operating temperature at which the supplied fuel can at least partially react on the thermal catalyst (2), and / or, The thermal catalyst (2) comprises at least one electric heating device which, in an eighth operating state, serves to heat the partial flow of the raw exhaust gas of the internal combustion engine (15) fed to the thermal catalyst (2).

9. The method according to any one of claims 1 to 8, characterized in that, The component (11, 12, 13) is selected from an oxidation catalyst (11) and / or a three-way catalyst and / or a selective catalytic reduction catalyst (13) and / or a particulate filter (12).

10. A data carrier storing data, wherein The data represent a computer program which, when executed on a microprocessor, carries out the method according to any one of claims 1 to 9.

11. A signal sequence representing data and adapted for transmission over a computer network, wherein, The data represent a computer program which, when executed on a microprocessor, carries out the method according to any one of claims 1 to 9.

12. An open- or closed-loop control device (3) designed to perform the method according to any one of claims 1 to 9.

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