Method for operating an internal combustion engine of a motor vehicle, in particular a car
Patent Information
- Application Number
- EP2024700788
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-02-09
- Filing Date
- 2024-01-16
- Publication Date
- 2025-12-17
AI Technical Summary
Existing methods for operating internal combustion engines in vehicles fail to achieve low-emission operation effectively, especially during dynamic driving conditions, as sensor-based monitoring of final emissions is sluggish and inefficient.
A method that calculates raw and final emission values using electronic computing models, allowing the internal combustion engine to be operated based on these values to limit load and prevent exceeding emission thresholds, incorporating a catalyst model to enhance exhaust gas aftertreatment and reduce emissions.
Enables quick and precise determination of final emissions, ensuring low-emission operation by limiting engine load and optimizing exhaust gas aftertreatment, thereby preventing emissions from exceeding predetermined levels.
Smart Images
Figure EP2024050894_15082024_PF_FP
Abstract
Description
[0001] Method for operating an internal combustion engine of a motor vehicle, in particular a motor vehicle
[0002] The invention relates to a method for operating an internal combustion engine of a motor vehicle, in particular a motor vehicle, according to the preamble of patent claim 1.
[0003] DE 102016 014 854 A1 discloses a method for exhaust gas aftertreatment for an internal combustion engine. Furthermore, DE 102010 002 620 A1 discloses a method for operating an SCR catalyst for the aftertreatment of exhaust gases from an internal combustion engine.
[0004] In addition, motor vehicles with internal combustion engines are known from the general state of the art and in particular from series vehicle construction, wherein the respective internal combustion engine has an exhaust tract through which exhaust gas from the internal combustion engine can flow and an exhaust gas aftertreatment device arranged in the exhaust tract, by means of which the exhaust gas is aftertreated.
[0005] The object of the present invention is to provide a method for operating an internal combustion engine of a motor vehicle so that particularly low-emission operation can be achieved.
[0006] This object is achieved according to the invention by a method having the features of patent claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.
[0007] The invention relates to a method for operating an internal combustion engine, also referred to as a motor, internal combustion engine or internal combustion engine, of a motor vehicle, also simply referred to as a vehicle, which is preferably designed as a motor car, in particular as a passenger car. In particular, it is provided that in the method or during the method, the motor vehicle is driven by means of the internal combustion engine. Very particularly, it is provided that the method is carried out during fired operation of the internal combustion engine, so that the internal combustion engine is preferably operated in fired mode, i.e., is operated in a fired state, during the method. The internal combustion engine has at least one combustion chamber in which combustion processes take place during fired operation of the internal combustion engine.During the respective combustion process, a fuel-air mixture, also simply referred to as a mixture, is ignited and combusted. The mixture comprises, in particular, a liquid fuel and a load. In particular, the internal combustion engine is designed as a spark-ignition engine, so that the fuel is, for example, gasoline. The mixture is ignited, for example, by external ignition and thus by means of an ignition device, in particular by the ignition device generating at least one ignition spark to ignite the mixture.
[0008] The internal combustion engine has an exhaust tract through which exhaust gas from the internal combustion engine flows. The exhaust gas originates, for example, from the combustion chamber and results from the combustion of the mixture, thus from the respective combustion process. The internal combustion engine also has an exhaust gas aftertreatment device arranged in the exhaust tract, by means of which the exhaust gas is aftertreated. Aftertreating the exhaust gas is to be understood in particular that the exhaust gas aftertreatment device converts, i.e., converts, first components contained in the exhaust gas into second components that are different from the first components. For this purpose, the exhaust gas aftertreatment device comprises, for example, at least one or precisely one catalyst, which can be designed, for example, as a three-way catalyst.
[0009] In order to be able to realize particularly low-emission operation of the internal combustion engine and thus of the motor vehicle as a whole, it is provided according to the invention that, in particular during the fired operation of the internal combustion engine, by means of an electronic computing device, in particular of the motor vehicle and very particularly of the internal combustion engine, at least one raw emission value is calculated, which characterizes raw emissions of the internal combustion engine, on the basis of a first calculation model stored in a particularly electrical or electronic data memory of the electronic computing device, which first calculation model is also referred to as a raw emission model.As is already known from the general state of the art, the raw emissions of an internal combustion engine are understood to be emissions contained in the exhaust gas before the exhaust gas flows through the exhaust gas aftertreatment device, i.e., before the exhaust gas is aftertreated by the exhaust gas aftertreatment device. Thus, the exhaust gas comprises the raw emissions in an untreated state of the exhaust gas, which is in its untreated state in the combustion chamber and before the exhaust gas is aftertreated by an exhaust gas aftertreatment device.
[0010] Furthermore, the method according to the invention provides that, by means of the electronic computing device, on the basis of a second computing model stored in the data memory and provided in particular in addition to the first computing model, at least one final emission value is calculated as a function of the raw emission value, in particular from the raw emission value. This final emission value characterizes emissions resulting from the raw emissions and from the aftertreatment of the exhaust gas effected by the exhaust gas aftertreatment device, leaving the exhaust tract and released into the environment of the motor vehicle as a whole. For example, the exhaust tract, also referred to as the exhaust system, opens into or onto the environment via at least or precisely one outlet opening, wherein the exhaust gas flows through the outlet opening and thereby flows out of the exhaust tract and into or onto the environment of the motor vehicle as a whole.In particular, for example, the outlet opening is formed by a tailpipe of the exhaust system, i.e., an opening of a tailpipe of the exhaust system. The tailpipe is also commonly referred to as a tailpipe, so the emissions characterized by the final emission value are also referred to as end emissions, tailpipe emissions, or tailpipe emissions. End emissions are emissions that flow from the exhaust system and onto or into the surroundings of the motor vehicle as a whole, i.e., are released from the motor vehicle into its surroundings.
[0011] Furthermore, the method according to the invention provides that the internal combustion engine is operated as a function of the final emission value, particularly during its fired operation. Thus, the internal combustion engine can be operated, for example, as a function of the final emission value such that the final emission value or the final emissions do not exceed a predeterminable or predetermined threshold, i.e., they fall below it, and / or an exceedance of the threshold by the final emission value or by the final emissions can be counteracted such that the threshold is only exceeded by the final emission value or the final emissions for a short time. Thus, particularly low-emission operation of the internal combustion engine can be ensured. In particular, the method according to the invention makes it possible to calculate and thereby monitor the final emission value or the final emissions.The background to the invention is, in particular, that sensor-based, in particular purely sensor-based, monitoring of final emissions is not possible or only possible with great effort. In contrast, the method according to the invention enables model-based calculation and thus determination of the final emissions, whereby the final emission value(s) can be determined quickly and precisely. Furthermore, the method according to the invention makes it possible to operate the internal combustion engine as a function of the final emission value, so that, for example, the final emission value(s) can prevent a limit value from being exceeded. In particular, the method according to the invention is an emissions observer, which is also referred to as an emissions observer.
[0012] For example, the second calculation model is also referred to as a catalyst model, particularly when the exhaust gas aftertreatment device has the aforementioned catalyst. For example, the calculation models as a whole are or form a physiochemical model, based on which the final emission value and thus the final emissions of the internal combustion engine can be calculated quickly and precisely. In particular, the raw emissions are emissions resulting from or during the combustion of the respective mixture, which can be advantageously calculated using the first calculation model. For example, the conversion capability of the exhaust gas aftertreatment device, in particular of the catalyst, can be calculated and thus determined using the second calculation model, whereby the final emission value can be calculated quickly and precisely using the second calculation model depending on the raw emission value.
[0013] The background of the invention is, in particular, that in dynamic driving situations, in which, for example, acceleration occurs up to the maximum possible speed of the motor vehicle, a certain level of final emissions may be exceeded despite maximum possible aftertreatment of the exhaust gas by the exhaust aftertreatment system. Sensor-based, in particular purely sensor-based, determination of final emissions is not possible or only possible with great effort, in particular because such a determination of final emissions is too sluggish and thus too slow.In contrast, the method according to the invention makes it possible to calculate the final emissions quickly and precisely so that, depending on the final emission value, the internal combustion engine can be operated, for example, in such a way that the level, also referred to as a limit or threshold value, or designed as a limit or threshold value, can be avoided by the final emissions.
[0014] In order to ensure particularly low emissions, an advantageous embodiment of the invention provides that the internal combustion engine is operated as a function of the final emission value in such a way that the maximum load that can be provided by the internal combustion engine to drive the motor vehicle is limited to a limit value. The load is or corresponds to a torque that can be provided by the internal combustion engine, in particular via its output shaft, designed, for example, as a crankshaft, to drive the motor vehicle, so that it is preferably provided, for example, that the maximum torque that can be provided by the internal combustion engine, in particular via its output shaft, to drive the motor vehicle is limited to the limit value.This allows the raw emissions, also known as exhaust pipe emissions, to be kept advantageously low, and the conversion capability of the exhaust aftertreatment system increases, so that the level can be avoided by the final emissions.
[0015] It has been shown to be particularly advantageous that during operation of the internal combustion engine prior to limiting the load and / or during operation of the internal combustion engine following limiting the load, a value of the maximum load that can be provided by the internal combustion engine or the maximum torque that can be provided by the internal combustion engine for driving the motor vehicle that is greater than the limit value is permitted.This means that limiting the maximum load that can be provided by the internal combustion engine to drive the motor vehicle means that the maximum load that can be provided by the internal combustion engine to drive the motor vehicle is reduced, in particular temporarily, compared to the operation of the internal combustion engine prior to and / or following the limitation, whereby particularly low-emission operation of the internal combustion engine and thus of the motor vehicle as a whole can be ensured.A further embodiment is characterized in that the final emission value is compared with a predetermined threshold value by means of the electronic computing device, wherein the maximum load that can be provided by the internal combustion engine to drive the motor vehicle is limited to the limit value if the comparison of the final emission value with the threshold value carried out by the electronic computing device shows that the final emission value exceeds the predetermined threshold value. This makes it possible to reliably and, in particular, predictively, i.e., in advance, prevent the final emissions from exceeding the aforementioned level. In other words, it is possible to limit the load on the internal combustion engine then and, in particular, before the final emissions actually exceed the level. This ensures particularly low-emission operation.
[0016] Limiting the load to the limit value is a possible substitute reaction which is carried out as a function of the final emission value, in particular as a reaction to the final emission value. Alternatively or additionally, a reaction or measure can be carried out as a substitute reaction which is carried out as a function of the final emission value, which for example comprises varying a combustion air ratio, also referred to as lambda, and / or an air-fuel mixture and / or varying control times, in particular valve control times and / or an intake and / or exhaust spread, and / or varying fuel injection, in particular with regard to different modes such as double, single, direct and / or intake manifold injection.Alternatively or additionally, the substitute reaction may comprise varying an engine speed and / or limiting it to a maximum speed value and / or varying an engine power of the internal combustion engine and / or limiting it to a maximum value.
[0017] In order to be able to calculate the raw emission value particularly quickly and precisely, it is provided in a further embodiment of the invention that the raw emission value is calculated using the first calculation model as a function of a load and a speed of the internal combustion engine.
[0018] A further embodiment is characterized by the fact that the raw emission value is calculated using the first calculation model as a function of the combustion engine's air / fuel ratio, also referred to as lambda or the Greek lowercase letter A. This allows the raw emission value to be calculated particularly quickly and precisely, so that the final emission value can subsequently be calculated quickly and precisely.
[0019] In a further, particularly advantageous embodiment of the invention, it is provided that, based on the second calculation model, the ability of the exhaust gas aftertreatment device to convert first components contained in the exhaust gas into second components that differ from the first components by aftertreating the exhaust gas is calculated, wherein "ability" is, for example, the aforementioned conversion capability. The final emission value is calculated as a function of the calculated ability. This allows the final emission value to be calculated quickly and precisely, so that the internal combustion engine can be operated particularly advantageously as a function of the final emission value. This ensures particularly low-emission operation.
[0020] A further embodiment is characterized in that the final emission value is calculated using the second calculation model as a function of at least one temperature of the exhaust gas aftertreatment device, by means of which the final emission value can be calculated quickly and precisely.
[0021] In order to achieve a particularly precise and rapid calculation of the final emission value, it has proven particularly advantageous if the temperature is measured using a temperature sensor of the internal combustion engine.
[0022] Finally, it has proven particularly advantageous if the final emission value is calculated using the second calculation model as a function of the amount of oxygen stored in the exhaust gas aftertreatment device and / or as a function of the velocity, particularly expressed as a space velocity, at which the exhaust gas flows through the exhaust gas aftertreatment device. This allows the final emission value to be calculated particularly precisely, thus enabling particularly low-emission operation.
[0023] Further details of the invention will become apparent from the following description of a preferred exemplary embodiment with the accompanying drawings. The sole FIG. 1 shows a schematic representation of an internal combustion engine of a motor vehicle. The sole FIG. 1 shows a schematic representation of an internal combustion engine 1, also referred to as a motor, internal combustion engine or internal combustion engine, of a motor vehicle, also simply referred to as a vehicle, which can be driven, in particular is driven, by means of the internal combustion engine 10. A method for operating the internal combustion engine 1 of the motor vehicle is described below with reference to FIG. 1. In particular, it is provided that the internal combustion engine 1 is operated in its fired mode during the method.The internal combustion engine 1 has a housing element 2, which is, for example, a cylinder housing, in particular a cylinder crankcase. The housing element 2 has a plurality of cylinders 3. A respective combustion chamber 4 of the internal combustion engine 1 is partially defined by the respective cylinder 3. A respective piston of the internal combustion engine 1 is accommodated in the respective cylinder 3 for translational movement, wherein the respective combustion chamber 4 is partially defined by the respective cylinder 3 and partially by the respective piston. Thus, the internal combustion engine 1 is designed, for example, as a reciprocating piston machine, thus as a reciprocating piston engine.
[0024] The internal combustion engine 1 has an intake tract 5 through which air can flow and is also referred to as the intake tract. An arrow 6 illustrates that the air, also referred to as fresh air, flows through the intake tract 5. By means of the intake tract 5, the air flowing through the intake tract 5 is guided to and into the combustion chambers 4. During a respective working cycle of the internal combustion engine 1, which is preferably designed as a four-stroke engine, a respective fuel-air mixture is formed in the respective combustion chamber 4, which is also simply referred to as a mixture. The respective mixture comprises the aforementioned air and a preferably liquid fuel. The internal combustion engine 1 is preferably a spark-ignition engine, i.e. a gasoline engine, so that the fuel is preferably a spark-ignition fuel, i.e. gasoline.Within the respective working cycle, the mixture is burned in the respective combustion chamber 4, resulting in exhaust gas from the internal combustion engine 1. The internal combustion engine 1 has an exhaust tract 7 through which the exhaust gas from the combustion chambers 4 flows, which is also referred to as the exhaust system. In Fig. 1, an arrow 8 illustrates that the exhaust gas flows through the exhaust tract 7. The internal combustion engine 1 has an exhaust gas aftertreatment device 9 arranged in the exhaust tract 7, which in the present case is the only exhaust gas aftertreatment device of the internal combustion engine 1 designed for aftertreating the exhaust gas. In the method, the exhaust gas flowing through the exhaust tract 7 and thus the exhaust gas aftertreatment device 9 is aftertreated by means of the exhaust gas aftertreatment device 9.In particular, it is provided that the exhaust gas aftertreatment device 9 comprises all exhaust gas aftertreatment components of the internal combustion engine 1, in particular of the motor vehicle as a whole, which are designed to aftertreat the exhaust gas, so that with regard to the motor vehicle as a whole, the exhaust gas can be and is aftertreated only with the exhaust gas aftertreatment device 9.
[0025] The arrow 8 shows that the exhaust system (the exhaust tract 7) opens into the environment 10 of the motor vehicle via at least or precisely one outflow opening. The outflow opening is formed, for example, by a tailpipe 11 of the exhaust tract 7, also referred to as a tailpipe, so that, for example, the exhaust gas flows through the tailpipe 11 as the last component of the motor vehicle on its way through the exhaust tract 7 and to or into the environment 10. On its way into or to the environment 10, the exhaust gas flows through the outflow opening, with the exhaust gas flowing through the outflow opening flowing out of the exhaust tract 7 and into or onto the environment 10.
[0026] In the respective combustion chamber 4 and in the exhaust tract 7 upstream of the exhaust aftertreatment device 9, the exhaust gas has raw emissions formed by first components contained in the exhaust gas. The raw emissions include, for example, carbon monoxide emissions (CO emissions) and / or unburned hydrocarbons (HC) and / or nitrogen oxide emissions (NOx emissions). In the tailpipe 11 and thus downstream of the exhaust aftertreatment device 9, the exhaust gas has final emissions, which result, for example, from the aftertreatment of the exhaust gas effected by the exhaust aftertreatment device 9 and from the raw emissions.During the aftertreatment of the exhaust gas, at least some, thus at least a portion of the first components are converted into second components that are different from the first components, for example by means of the exhaust gas aftertreatment device 9, so that, for example, the final emissions comprise the second components and possibly a portion of the first components that is not converted by the exhaust gas aftertreatment device 9.
[0027] In order to be able to realize a particularly low-emission operation of the internal combustion engine 1 and thus of the motor vehicle as a whole, at least one raw emission value which characterizes the raw emissions of the internal combustion engine 1 is calculated, in particular during the fired operation of the internal combustion engine 1, by means of an electronic computing device 12 of the motor vehicle, in particular of the internal combustion engine 1, on the basis of a first calculation model 14 stored in a data memory 13 of the electronic computing device 12.In addition, by means of the electronic computing device 12, on the basis of a second computing model 15 stored in the data memory 13 and provided in particular in addition to the first computing model 14, at least one final emission value is calculated as a function of the raw emission value, which final emission value characterizes, i.e. describes or indicates the final emissions resulting from the raw emissions and the aftertreatment of the exhaust gas, leaving the exhaust tract 7 and released into the environment 10 of the motor vehicle, which final emissions are also simply referred to as emissions.Furthermore, it is provided that the internal combustion engine 1 is operated by means of the electronic computing device 12 as a function of the calculated final emission value, in particular in such a way that, as a function of the final emission value, a maximum load that can be provided by the internal combustion engine 1 or a torque for driving the motor vehicle is temporarily limited to a limit value and thus at least during a first period of time.In this case, it is provided, for example, that during a second period preceding the first period and / or during a third period following the first period, a value of the maximum load or torque that can be provided by the internal combustion engine 1 to drive the motor vehicle that is greater than the limit value is permitted, so that the maximum load that can be provided by the internal combustion engine 1 to drive the motor vehicle is lower during the first period than during the second period and lower than during the third period. This can prevent the final emissions from exceeding a level that can be defined, for example, as a limit or threshold, so that particularly low-emission operation of the internal combustion engine 1 and thus of the motor vehicle as a whole can be ensured.
[0028] For example, the second calculation model calculates a capability, also referred to as conversion capability, for several volume elements, in particular volume slices, of the exhaust gas aftertreatment device 9, arranged adjacent to one another or successively, for example, to convert the final components contained in the exhaust gas upstream of the exhaust gas aftertreatment device 9 into second components that differ from the first components. In particular, it is provided that the volume elements follow one another, for example in the flow direction of the exhaust gas flowing through the exhaust gas aftertreatment device 9. The conversion of the first components into the second components caused by the volume elements results in the final emissions, which can be determined quickly and precisely by calculating the final emission value using the method.As a result, for example, the internal combustion engine 1 can be operated in a forward-looking and thus predictive manner to prevent the final emissions from exceeding the specified level. This is done, for example, by limiting the maximum load that the internal combustion engine 1 can provide to drive the motor vehicle if the electronic computing device 12 determines that the final emissions value exceeds a predetermined threshold. This can prevent the final emissions from exceeding the specified level.
[0029] List of reference symbols
[0030] internal combustion engine
[0031] Housing element
[0032] cylinder
[0033] combustion chamber
[0034] Intake tract
[0035] Arrow
[0036] exhaust tract
[0037] Arrow
[0038] Exhaust aftertreatment system
[0039] Vicinity
[0040] tailpipe electronic computing device
[0041] Data storage first calculation model second calculation model
Claims
Patent claims 1. A method for operating an internal combustion engine (1) of a motor vehicle, in which the internal combustion engine (1) has an exhaust tract (7) through which exhaust gas from the internal combustion engine (1) can flow, and an exhaust gas aftertreatment device (9) arranged in the exhaust tract (7), by means of which the exhaust gas is aftertreated, characterized in that: - by means of an electronic computing device (12) on the basis of a first calculation model (14) stored in a data memory (13) of the electronic computing device (12), at least one raw emission value is calculated, which characterises raw emissions of the internal combustion engine (1); - by means of the electronic computing device (12) on the basis of a second calculation model (15) stored in the data memory (13), at least one final emission value is calculated as a function of the raw emission value, which characterises emissions resulting from the raw emissions and the aftertreatment of the exhaust gas, leaving the exhaust tract (7) and released into an environment (10) of the motor vehicle; and - the internal combustion engine (1) is operated depending on the final emission value.
2. Method according to claim 1, characterized in that the internal combustion engine (1) is operated as a function of the final emission value in such a way that a maximum load that can be provided by the internal combustion engine (1) for driving the motor vehicle is limited to a limit value.
3. Method according to claim 2, characterized in that during an operation of the internal combustion engine (1) preceding the limiting of the load and / or during an operation of the internal combustion engine (1) following the limiting of the load, a the maximum load that can be provided by the internal combustion engine (1) to drive the motor vehicle is permitted to be greater than the limit value.
4. Method according to claim 2 or 3, characterized in that the final emission value is compared with a predetermined threshold value by means of the electronic computing device (12), wherein the maximum load that can be provided by the internal combustion engine (1) for driving the motor vehicle is limited to the limit value if the comparison shows that the final emission value exceeds the predetermined threshold value.
5. Method according to one of the preceding claims, characterized in that the raw emission value is calculated using the first calculation model (14) as a function of a load and a speed of the internal combustion engine (1).
6. Method according to one of the preceding claims, characterized in that the raw emission value is calculated using the first calculation model (14) as a function of a combustion air ratio of the internal combustion engine (1).
7. Method according to one of the preceding claims, characterized in that, based on the second calculation model (15), a capability of the exhaust gas aftertreatment device (19) to convert first components contained in the exhaust gas into second components different from the first components by aftertreating the exhaust gas is calculated, wherein the final emission value is calculated as a function of the calculated capability.
8. Method according to one of the preceding claims, characterized in that the final emission value is calculated using the second calculation model (15) as a function of at least one temperature of the exhaust gas aftertreatment device (9).
9. The method according to claim 8, characterized in that the temperature is measured by means of a temperature sensor of the internal combustion engine (1).
10. Method according to one of the preceding claims, characterized in that the final emission value is calculated using the second calculation model (!5) as a function of an amount of oxygen stored in the exhaust gas aftertreatment device (9) and / or as a function of a speed at which the exhaust gas flows through the exhaust gas aftertreatment device (9).