Method for operating an internal combustion engine

Abstract

Method for operating an internal combustion engine (1), wherein the internal combustion engine (1) has at least one inlet side (2), at least one combustion chamber (3), one outlet side (4) for an exhaust gas (5), at least one valve (6) on the outlet side (4) and at least one exhaust gas recirculation arrangement (7, 8) for recirculating the exhaust gas (5) from the outlet side (4) to the inlet side (2); wherein the method comprises at least the following steps: a) Determining a positive load jump (9); b) Opening the at least one valve (6) on the exhaust side (4) during at least one working cycle (10) in the at least one combustion chamber (3), so that the exhaust gas (5) is drawn from the exhaust side (4) via the valve (6) into the combustion chamber (3); characterized in that a number of work cycles (10) carried out in step b) is determined depending on at least one of the following first parameters (11): - a first volume (12) of the at least one exhaust gas recirculation arrangement (7, 8); - the proportion of an inert gas present at a time during step b) in the at least one exhaust gas recirculation arrangement (7, 8); - a duration of a low-load phase or thrust phase immediately preceding step a) (13); - a target inert gas content in the at least one combustion chamber (3).

Description

[0001] The invention relates to a method for operating an internal combustion engine. The method can be carried out in a motor vehicle.

[0002] Modern diesel engines meeting EU6 and more stringent emissions standards are typically equipped with a high-pressure exhaust gas recirculation (EGR) system (usually connecting the exhaust side immediately downstream of the combustion chamber to the intake side immediately upstream of the combustion chamber) and a low-pressure EGR system (usually connecting the exhaust side downstream of an exhaust turbine in a turbocharger to the intake side upstream of a compressor in the turbocharger). The alternative or combined operation of these so-called external EGR systems can effectively reduce raw nitrogen oxide (NOx) emissions in steady-state or low-dynamic operating conditions.

[0003] Particularly after prolonged periods of deceleration (a deceleration phase is characterized by the fact that – although airflow is present – ​​no additional fuel is required, as the movement of the internal combustion engine is maintained by the rotation imposed via the drivetrain), the exhaust gas recirculation lines can fill with fresh air. This is due to gas pulsations in the exhaust system (exhaust side) and intake manifold (intake side), as well as to the fact that the exhaust gas recirculation valves do not close completely.

[0004] If, after this long overrun phase, the internal combustion engine restarts (i.e., is driven by ignition processes in at least one combustion chamber), resulting in a positive load change, then at least one exhaust gas recirculation (EGR) system can be connected to the intake side to set a target EGR rate. Until a certain volume of the EGR system is emptied, the inert gas fraction that is "normal" or desired in steady-state operation is not returned to the intake side. Due to the fresh air introduced into the EGR system, the actual inert gas fraction (proportion of exhaust gas) in the combustion chamber is lower for a certain number of combustion chamber loads than in steady state, so that a temporary increase in raw nitrogen oxide emissions can be observed.

[0005] This effect, albeit to a lesser degree, can also be observed during positive load transitions from low to high loads (torques at the crankshaft of the internal combustion engine). Temporary peaks in raw nitrogen oxide emissions can also occur in these cases.

[0006] Therefore, the volume of the external exhaust gas recirculation system should be as small as possible. However, a virtually instantaneous response of the actual inert gas rate to a target inert gas rate is not possible for geometric reasons, because the gas transport from the exhaust side to the intake side always requires a certain volume in the transport path (exhaust gas recirculation system).

[0007] As known from WO 2007 / 056784 A2, an internal exhaust gas recirculation system is used in the low and medium load range of an internal combustion engine. In this system, exhaust gas is recirculated back into the combustion chamber via a valve on the exhaust side. This valve opens during the intake stroke of the combustion chamber to draw exhaust gas from the exhaust side back into the combustion chamber. This is particularly common at engine speeds below 2,500 rpm and loads below 150 Nm. This recirculated exhaust gas is uncooled, so recirculating it at higher loads and thus higher exhaust gas temperatures would adversely increase the charge temperature. This would mean that the reduction in nitrogen oxides (NOx) achieved through the inert gas blend would be more than offset by the increase in NOx emissions resulting from the higher combustion temperatures in the combustion chamber.

[0008] DE 10 2011 006 056 A1 relates to a method for controlling combustion in a combustion chamber.

[0009] US Patent 9,726,093 B2 relates to a device for estimating the amount of exhaust gas to be recirculated.

[0010] The object of the present invention is to at least partially solve the problems cited with reference to the prior art. In particular, a method for operating an internal combustion engine is to be proposed by which nitrogen oxide emissions can be further reduced.

[0011] A method with the features according to claim 1 contributes to solving these problems. Advantageous further developments are the subject of the dependent claims. The features listed individually in the claims can be combined with one another in a technologically meaningful way and can be supplemented by explanatory facts from the description and / or details from the figures, thereby demonstrating further embodiments of the invention.

[0012] A method for operating an internal combustion engine, in particular a diesel engine, is proposed. The method is preferably carried out in a motor vehicle. The internal combustion engine comprises at least one intake side, at least one combustion chamber, an exhaust side for exhaust gas, at least one valve on the exhaust side, and at least one exhaust gas recirculation arrangement for recirculating exhaust gas from the exhaust side to the intake side. The method includes at least the following steps: a) Determining a positive load jump; b) Opening the at least one valve on the exhaust side during at least one working cycle in the at least one combustion chamber, so that exhaust gas is drawn from the exhaust side into the combustion chamber via the valve.

[0013] An internal combustion engine, in particular a diesel engine, comprises in particular at least one intake side, at least one combustion chamber, an exhaust side for exhaust gas, at least one valve on the exhaust side, and at least one exhaust gas recirculation system (optionally also two exhaust gas recirculation systems, e.g., a high-pressure and a low-pressure exhaust gas recirculation system) for recirculating exhaust gas from the exhaust side to the intake side. Fresh air is supplied to the at least one combustion chamber via the intake side, e.g., via an intake manifold. The combustion of the fuel with air takes place in the combustion chamber, with a piston moving within the combustion chamber driving a crankshaft of the internal combustion engine. The exhaust gas produced as a result of the combustion processes in the combustion chamber is supplied via the at least one valve on an exhaust side. The exhaust side connects to or...It includes an exhaust pipe that can be connected to the intake side via an exhaust gas recirculation system for the recirculation of exhaust gas.

[0014] A load step is, in particular, a change in the torque acting on the crankshaft within a specific time period. This occurs especially during the transition from a deceleration phase to a traction phase, whereby, during a traction phase, the crankshaft is accelerated (towards higher speeds) by fuel injection and ignition of the fuel-air mixture. The load step specifically refers to a change in the torque acting on the crankshaft, e.g., by at least 10%, preferably by at least 20%, particularly within a predetermined time period, e.g., within 1 second, preferably within 0.5 seconds.

[0015] If such a positive load change is detected and / or executed, at least one valve on the exhaust side opens in accordance with step b), particularly (exclusively) during the intake stroke of at least one power cycle (power cycle of, for example, a four-stroke engine: intake, compression and ignition, power, exhaust). This allows exhaust gas to be recirculated into the combustion chamber, so that the proportion of inert gas in the combustion chamber can be increased or adjusted for the next ignition process.

[0016] In particular, the degree of opening and / or the duration of the opening can be regulated so that a predetermined amount of exhaust gas can be reintroduced into the combustion chamber via the valve.

[0017] The proposal specifically suggests installing an internal exhaust gas recirculation system that allows exhaust gas from the exhaust side to be transferred directly into the combustion chamber. This enables the adjustment of the required proportion of inert gas in the combustion chamber to reduce nitrogen oxide emissions, even though the at least one external exhaust gas recirculation system may supply almost exclusively fresh air (and no inert gas).

[0018] During step b), the exhaust gas can be recirculated via the at least one (external) exhaust gas recirculation arrangement into the at least one combustion chamber via the inlet side. The fresh air present in the at least one exhaust gas recirculation arrangement can be successively supplied to the combustion chamber, whereby the exhaust gas recirculation arrangement refills with exhaust gas as an inert gas, starting from the outlet side.

[0019] In step b), the at least one valve can be opened for a plurality (e.g. a precisely determinable number) of working cycles to draw exhaust gas into the at least one combustion chamber.

[0020] In particular, the valve can be opened during 1 to 15 operating cycles, preferably during 5 to 15 operating cycles (each during the intake stroke of an operating cycle). After this, it can be assumed that sufficient or predetermined quantities of inert gas are supplied via the at least one external exhaust gas recirculation arrangement.

[0021] In particular, the number of work cycles performed in step b) is determined depending on at least one of the following first parameters: - a first volume of at least one first exhaust gas recirculation arrangement (the larger the first volume, the more fresh air may be contained therein, which must be successively transferred into the combustion chamber); - at a time during step b) the proportion of an inert gas present in the at least one exhaust gas recirculation arrangement (if necessary, a proportion of inert gas is still contained here, whereby this proportion can be supplemented by exhaust gas supplied via the valve); - the duration of a low-load phase or overrun phase immediately preceding step a) (the longer this duration, the more fresh air may have accumulated in the exhaust gas recirculation system); - a target inert gas content in the at least one combustion chamber; - a back pressure in an intake manifold located on the intake side (this back pressure can influence the fresh air intake into the exhaust gas recirculation line); - exhaust back pressure on the outlet side (this exhaust back pressure can influence the fresh air intake into the exhaust gas recirculation line); - a temperature in an intake manifold located on the intake side (the temperature can cause a further increase in the mixture temperature due to the exhaust gas supplied via the valve, thus increasing nitrogen oxide emissions); - an exhaust gas temperature (the exhaust gas temperature can lead to a further increase in the mixture temperature due to the exhaust gas supplied via the valve, thus increasing nitrogen oxide emissions); - the rotational speed of a crankshaft of an internal combustion engine (the rotational speed and / or the change in rotational speed can characterize the need for inert gas as a result of the load change); - a load present on a crankshaft of the internal combustion engine (the load and / or the change in the load characterizes the load jump).

[0022] The number of work cycles determined (based on at least one first parameter) can be corrected depending on at least one of the following second parameters: - at least one measurement from a lambda sensor located on the exhaust side (as close as possible to at least one combustion chamber) (if the lambda measurement is higher than expected, more work cycles can be carried out according to step b); if the lambda measurement is lower than expected, step b), i.e. the opening of the valve in the intake stroke, can be terminated faster or immediately); - a combustion chamber pressure curve.

[0023] In particular, the combustion chamber pressure profile can be determined using a pressure sensor or by analyzing the change in rotational speed during one crankshaft revolution (crankshaft angle-resolved rotational speed profile). The number of combustion cycles can then be increased if the peak pressure or pressure rise is higher than expected. Conversely, the number of combustion cycles can be decreased if the peak pressure or pressure rise is lower than expected.

[0024] The number of work cycles can be determined, at least through modeling that takes into account at least one first parameter. Modeling here means, in particular, that the first parameter does not allow direct control of the inert gas supply, but can only be used in conjunction with other factors, or at least one first parameter and at least one second parameter, to carry out step b).

[0025] Monitoring the inert gas content in at least one exhaust gas recirculation line could be achieved, for example, using a lambda sensor. With a lambda sensor, the process, i.e., the initiation of step b), could then be precisely adjusted. However, such lambda sensors are expensive, so it is advisable to utilize the measured values ​​of existing sensors.

[0026] In particular, the procedure is carried out independently of the crankshaft speed of the internal combustion engine and independently of any load applied to the crankshaft. Specifically, the procedure is carried out or initiated solely based on the load step. The load step can be assumed to be the starting point of the procedure at any engine speed and regardless of the degree of load change. Thus, if a load step is detected, step b) is initiated (directly or immediately), regardless of the engine speed and regardless of the degree of load change. However, step b) is not carried out if, due to the absence of preceding overrun phases, it can be assumed that only a negligible amount of fresh air is present in the exhaust gas recirculation system.

[0027] Furthermore, a motor vehicle with an internal combustion engine is proposed, wherein the internal combustion engine has at least one intake side, at least one combustion chamber, one exhaust side for exhaust gas, at least one variably controllable valve on the exhaust side, and at least one exhaust gas recirculation arrangement for recirculating exhaust gas from the exhaust side to the intake side, as well as a control unit. The control unit is designed to carry out the procedure described above (provided and configured), wherein a positive load step is detectable by the control unit and the valve can be actuated via the control unit to carry out step b) of the procedure.

[0028] The explanations regarding the procedure apply equally to motor vehicles and vice versa.

[0029] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described.

[0030] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations described in the figures and combine them with other components and findings from the present description. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. They show: Fig. 1: a motor vehicle with an internal combustion engine; Fig. 2: a valve stroke depending on the working cycle; Fig. 3: a time course of various parameters; and Fig. 4: a time course of various parameters with the activation of an internal exhaust gas recirculation arrangement.

[0031] The Fig. Figure 1 shows a motor vehicle 25 with a first (low-pressure) exhaust gas recirculation arrangement 7 and a second (high-pressure) exhaust gas recirculation arrangement 8.

[0032] The internal combustion engine 1 has an inlet side 2 and an outlet side 4, as well as at least one variably controllable valve 6 on the outlet side 4 and two external exhaust gas recirculation arrangements 7, 8 for recirculating the exhaust gas 5 from the outlet side 4 to the inlet side 2. A control unit 27 is also provided. A positive load step 9 is detectable via the control unit 27, and the valve 6 can be actuated by the control unit 27 to carry out step b) of the process. A gas mixture enters the combustion chambers 3 of the internal combustion engine 1 via the inlet side 2. The exhaust gas 5 enters the exhaust line via the outlet side 4. The exhaust line connects the outlet side 4 of the internal combustion engine 1 to several exhaust gas treatment units 36 and to the environment, to which the exhaust gas 5 is ultimately discharged.The first exhaust gas recirculation arrangement 7 is a low-pressure exhaust gas recirculation arrangement that branches off from the exhaust gas line downstream of the exhaust gas turbocharger 35 and recirculates at least a portion of the exhaust gas flow back to the inlet side 2. Fresh air 34 is supplied to the inlet side 2 via a fresh air supply. The exhaust gas turbocharger 35 is driven by the exhaust gas 5 in the exhaust gas line and serves to compress the gas supplied via the fresh air supply and / or the first exhaust gas recirculation arrangement 7 (exhaust gas 5, fresh air 34, etc.).

[0033] The first exhaust gas recirculation arrangement 7 includes an exhaust gas treatment unit 36 ​​(e.g. a filter), a cooler 37 and a low-pressure exhaust gas recirculation (LP-EGR) valve 32.

[0034] A throttle valve 28 is arranged between the compressor of the exhaust gas turbocharger 35 and the intake side 2. The intake side 2 comprises an intake manifold 15 and a cooler 37.

[0035] The internal combustion engine 1 additionally comprises a second exhaust gas recirculation arrangement 8, which is flow-conductingly connected on one side to the exhaust pipe upstream of the exhaust gas turbocharger 35 and on the other side to the intake side 2 downstream of the compressor, downstream of the throttle valve 28 and downstream of the charge air cooler 37. The second exhaust gas recirculation arrangement 8 is a high-pressure exhaust gas recirculation arrangement 8, which recirculates exhaust gas 5 from the exhaust side 4 via the intake side 2 to the combustion chambers 3. The second exhaust gas recirculation arrangement 8 has a high-pressure exhaust gas recirculation (HP-EGR) valve 49, via which the second exhaust gas recirculation arrangement 8 can be closed.

[0036] During operation of the internal combustion engine 1, fresh air 34 is supplied to the combustion chambers 3 via the intake side 2, or via the intake manifold 15. Ignition takes place in the combustion chambers 3, with a piston moving in each combustion chamber 3 driving a crankshaft 26 of the internal combustion engine 1. The exhaust gas 5 produced as a result of the combustion processes in the combustion chamber 3 is fed to an exhaust side 4 via the valve 6.

[0037] If a positive load jump occurs (see Fig. 3 and Fig. 4) If the condition is determined, then, according to step b), at least one valve 6 on the outlet side 4 is opened. This allows exhaust gas 5 to be pumped back into the combustion chamber 3, so that the proportion of inert gas in the combustion chamber 3 can be increased or adjusted for the next ignition process.

[0038] It is therefore proposed in particular to install an internal exhaust gas recirculation arrangement through which exhaust gas 5 from the outlet side 4 can be transferred directly into the combustion chamber 3. This allows the proportion of inert gas required to reduce nitrogen oxide emissions 44 to be adjusted in the combustion chamber 3, even though, if necessary, the external exhaust gas recirculation arrangement 7, 8 can supply almost exclusively fresh air 34 (and no inert gas).

[0039] When controlling the activity 47 of the internal exhaust gas recirculation arrangement via the switching device 31, which is actuated via the control unit 27, the following first parameters 11 can be taken into account, for example: A volume 12 of the respective exhaust gas recirculation arrangement 7, 8, a duration of a low-load phase or overrun phase 13 immediately preceding step a), a back pressure 14 in an intake manifold 15 located on the intake side 2, an exhaust back pressure 16 on the exhaust side 4, a temperature 17 in an intake manifold 15 located on the intake side 2, an exhaust gas temperature 18, a rotational speed 19 of a crankshaft 26 of the internal combustion engine 1, a load 20 present on a crankshaft 26 of the internal combustion engine 1.

[0040] The number of work cycles 10 determined (based on at least one first parameter 11) can be corrected depending on at least one of the following second parameters 21: at least one measured value 22 of a lambda sensor 23 arranged on the exhaust side 4 (as close as possible to at least one combustion chamber 3), a combustion chamber pressure curve 24 measured via a pressure sensor 29 or with a tachometer 30 - via an evaluation of the change in rotational speed 19 during one crankshaft revolution (crankshaft angle-resolved rotational speed curve).

[0041] The motor vehicle 25 may have additional pressure sensors 29, temperature sensors 33 and lambda probes 23.

[0042] Fig. Figure 2 shows a valve lift 38 as a function of the working cycle 10. The vertical axis represents the valve lift 38, and the horizontal axis represents the crankshaft angle 41 (0 to 360 degrees). The working cycle 10 comprises four strokes, consisting of: first, powering (up to bottom dead center 42); then, exhausting the exhaust gas 5 from the combustion chamber 3 (valve 6 open; between bottom dead center 42 and top dead center 43); followed by intake (intake valve open, valve 6 partially open; between top dead center 43 and bottom dead center 42); and finally, compression (after bottom dead center 42). The first curve 39 shows the valve lift 38 of valve 6, through which the combustion chamber 3 is connected to the exhaust side 4. The second diagram 40 shows the valve lift 38 of an inlet valve, via which the combustion chamber 3 can be connected to the inlet side 2.

[0043] Therefore, if there is a positive load jump 9 (see Fig. 3 and Fig. 4) If, as determined in step b), at least one valve 6 on the exhaust side 4 is opened at least partially during intake via the intake valve, exhaust gas 5 can be returned to the combustion chamber 3, so that the proportion of inert gas in the combustion chamber 3 can be increased or adjusted for the next ignition process.

[0044] Fig. Figure 3 shows a time course of various parameters, where there is no activity 47 of an internal exhaust gas recirculation arrangement.

[0045] The vertical axis shows nitrogen oxide emissions 44, oxygen content 45 in the combustion chamber 3 (after intake, before ignition), valve position 46 of the low-pressure EGR valve 32, and the load 20. The horizontal axis shows time 48.

[0046] After a deceleration phase 13, the exhaust gas recirculation devices 7, 8 can fill with fresh air 34. If, after this deceleration phase 13, the internal combustion engine 1 restarts and thus a positive load jump 9 to a higher load 20 occurs, at least one exhaust gas recirculation device 7 is connected to the intake side 2 via the low-pressure EGR valve 32 to set a target EGR rate (target "exhaust gas return" rate). However, until a volume 12 of the exhaust gas recirculation device 7 is emptied, the "normal" or desired inert gas fraction from the steady state is not recirculated to the intake side 2. Due to the fresh air 34 introduced into the exhaust gas recirculation arrangement 7, the actual inert gas content (proportion of exhaust gas 5) in the combustion chamber 3 is smaller for a certain number of combustion chamber fillings than in the steady state (oxygen content 45 remains high), so that a temporary increase in nitrogen oxide emissions 44 can be observed.

[0047] Fig. Figure 4 shows a time course of various parameters with the activation of an internal exhaust gas recirculation system. The vertical axis shows nitrogen oxide emissions 44, oxygen content 45 in the combustion chamber 3 (after intake, before ignition), valve position 46 of the low-pressure EGR valve 32, the load 20, and the activity 47 of the internal exhaust gas recirculation system. The horizontal axis shows time 48. See the explanations regarding Fig. Reference is made to point 3.

[0048] Unlike Fig.3. An internal exhaust gas recirculation arrangement is used here. According to step a) of the procedure, after the overrun phase 13, a positive load jump 9 to a higher load 20 is detected. Subsequently, in step b), at least one valve 6 on the exhaust side 4 is opened during at least one operating cycle 10 in at least one combustion chamber 3, so that exhaust gas 5 from the exhaust side 4 can be drawn into the combustion chamber 3 via the valve 6. Activity 47 illustrates the time 48 during which the valve 6 is at least partially open even while the combustion chamber 3 is connected to the intake side 2 via an intake valve. Here, too, an exhaust gas recirculation arrangement 7 is connected to the intake side 2 via the low-pressure EGR valve 32 to set a target EGR rate (target "exhaust gas return" rate).Until a volume 12 of the exhaust gas recirculation arrangement 7 is emptied, the activity 47 of the internal exhaust gas recirculation arrangement is present, so that the oxygen content 45 in the combustion chamber 3 and the nitrogen oxide emissions 44 can be reduced. Reference symbol list 1 Internal combustion engine 2 Entrance side 3 Combustion chamber 4 Outlet side 5 Exhaust gas 6 valve 7 first exhaust gas recirculation arrangement 8 second exhaust gas recirculation arrangement 9 Load jump 10 work game 11 first parameter 12 first volume 13. Push phase 14 Counterpressure 15 Intake pipe 16 Exhaust back pressure 17 Temperature 18 Exhaust gas temperature 19 rpm 20 Last 21 second parameter 22 measured values 23 Lambda sensor 24 Combustion chamber pressure curve 25 motor vehicle 26 Crankshaft 27 Control unit 28 Throttle valve 29 Pressure sensor 30 Tachometer 31 Switching device 32 ND-EGR valve 33 Temperature sensor 34 Fresh air 35 exhaust gas turbochargers 36 Exhaust gas treatment unit 37 coolers 38 valve lift 39 first course 40 second course 41 Crankshaft angle 42 bottom dead center 43 top dead center 44 Nitrogen oxide emissions 45% oxygen content 46 Valve position 47 Activity iAGR 48 Time 49 HD-EGR valve

Claims

Method for operating an internal combustion engine (1), wherein the internal combustion engine (1) has at least one inlet side (2), at least one combustion chamber (3), an outlet side (4) for an exhaust gas (5), at least one valve (6) on the outlet side (4) and at least one exhaust gas recirculation arrangement (7, 8) for recirculating the exhaust gas (5) from the outlet side (4) to the inlet side (2); wherein the method comprises at least the following steps: a) detecting a positive load step (9); b) opening the at least one valve (6) on the outlet side (4) during at least one working cycle (10) in the at least one combustion chamber (3), so that the exhaust gas (5) is drawn from the outlet side (4) through the valve (6) into the combustion chamber (3);characterized in that a number of work cycles (10) carried out in step b) is determined as a function of at least one of the following first parameters (11): - a first volume (12) of the at least one exhaust gas recirculation arrangement (7, 8); - the proportion of an inert gas present in the at least one exhaust gas recirculation arrangement (7, 8) at a time point in step b); - the duration of a low-load phase or overrun phase (13) present immediately before step a); - a target inert gas proportion in the at least one combustion chamber (3).; Method according to claim 1, wherein during step b) the exhaust gas (5) is returned via the inlet side (2) to the at least one combustion chamber (3) via the at least one exhaust gas recirculation arrangement (7, 8). Method according to one of the preceding claims, wherein in step b) the at least one valve (6) is opened over a plurality of working cycles (10) to draw exhaust gas (5) into the at least one combustion chamber (3). Method according to one of the preceding claims, wherein a number of work cycles (10) carried out in step b) is determined as a function of at least one of the following first parameters (11): - a back pressure (14) in an intake manifold (15) located on the intake side (2); - an exhaust back pressure (16) on the exhaust side (4); - a temperature (17) in an intake manifold (15) located on the intake side (2); - an exhaust gas temperature (18); - a rotational speed (19) of a crankshaft (26) of the internal combustion engine (1); - a load (20) present on a crankshaft (26) of the internal combustion engine (1). Method according to one of the preceding claims, wherein the determined number of work cycles (10) is corrected depending on at least one of the following second parameters (21): - at least one measured value (22) of a lambda probe (23) arranged on the outlet side (4); - a combustion chamber pressure profile (24). Method according to one of the preceding claims, wherein the number of work cycles (10) is determined at least by modeling taking into account the at least one first parameter (11). Method according to one of the preceding claims, wherein the method is carried out independently of a rotational speed (19) of a crankshaft (26) of the internal combustion engine (1) and independently of a load (20) applied to the crankshaft (26). Motor vehicle (25) with an internal combustion engine (1), wherein the internal combustion engine (1) has at least one inlet side (2), at least one combustion chamber (3), an outlet side (4) for an exhaust gas (5), at least one variably controllable valve (6) on the outlet side (4) and at least one exhaust gas recirculation arrangement (7, 8) for recirculating an exhaust gas (5) from the outlet side (4) to the inlet side (2) as well as a control unit (27); wherein the control unit (27) is configured to carry out the method according to one of the preceding claims, wherein a positive load step (9) is detectable by the control unit (27) and the valve (6) can be actuated via the control unit (27) to carry out step b) of the method.

Images