DE102024119579A1 - Method for operating an internal combustion engine of a motor vehicle and internal combustion engine for a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating an internal combustion engine (1) of a motor vehicle, in which the internal combustion engine (1) has at least one combustion chamber (4a) to which at least one gas exchange valve is assigned, which is moved from a closed position to an open position and from the open position back to the closed position during each operating cycle of the internal combustion engine (1). A structure-borne sound sensor measures the structure-borne sound of the internal combustion engine (1) and provides a structure-borne sound signal characterizing the measured structure-borne sound. Alternatively or additionally, a pressure sensor measures the pressure prevailing in the combustion chamber (4a) and provides a pressure signal characterizing the measured pressure. Based on the structure-borne sound signal and/or the pressure signal, a value is determined that characterizes a time at which the gas exchange valve reaches the closed position during at least one of the operating cycles of the internal combustion engine (1). The internal combustion engine (1) is operated depending on the determined value.

Description

The invention relates to a method for operating an internal combustion engine of a motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to an internal combustion engine for a motor vehicle.

The JP 2013-29076 A discloses a method for detecting combustion noise in an internal combustion engine. From the US 10 161 334 B2 A method for an engine is known. JP 5928354 B2 It is a known spark-ignition engine. Furthermore, the DE 10 2014 010 454 A1 a method for controlling combustion in an internal combustion engine.

The object of the present invention is to provide a method for operating an internal combustion engine of a motor vehicle and an internal combustion engine for a motor vehicle, so that a particularly advantageous operation of the internal combustion engine can be realized.

This problem is solved according to the invention by a method with the features of claim 1 and by an internal combustion engine with the features of claim 10. Advantageous embodiments of the invention are the subject of the dependent claims.

A first aspect of the invention relates to a method for operating an internal combustion engine, also referred to as a combustion engine, of a motor vehicle, also referred to simply as a vehicle, which is preferably a motor car, in particular a passenger car. In particular, it is provided that the method is carried out while the motor vehicle is in motion and is powered by the internal combustion engine. In particular, it is provided that the internal combustion engine is operated in its fired mode during the method. In the method, the internal combustion engine has at least one combustion chamber, which is also referred to as the first combustion chamber. Whenever the combustion chamber or the at least one combustion chamber is mentioned before and after, this refers to the first combustion chamber unless otherwise specified. The combustion chamber is associated with at least one gas exchange valve, which is also referred to as the first gas exchange valve. Whenever the gas exchange valve or the at least one gas exchange valve is mentioned before and after, this refers to the first gas exchange valve unless otherwise specified. In this process, the internal combustion engine performs several operating cycles, with the operating cycles following one another. Within each operating cycle, the gas exchange valve is moved from a closed position to an open position and then back from the open position to the closed position. Most preferably, the internal combustion engine is designed as a reciprocating piston engine. The internal combustion engine has an engine block, which is a first housing element of the engine. In particular, the engine block is a cylinder housing, especially a cylinder crankcase. The engine block has at least one cylinder, which is also referred to as the first cylinder. When the cylinder or the at least one cylinder is mentioned before and after, unless otherwise specified, this refers to the first cylinder. A piston of the internal combustion engine is mounted in the cylinder so as to be translationally movable, and this piston is also referred to as the first piston. When the piston is mentioned before and after, unless otherwise specified, this refers to the first piston. Furthermore, the internal combustion engine has, for example, a second housing element, separate from the engine block, which is connected to the engine block. For example, the second housing element is a cylinder head. The second housing element has at least one combustion chamber roof, which is also referred to as the first combustion chamber roof. When the combustion chamber roof or the at least one combustion chamber roof is mentioned before and below, this refers, unless otherwise specified, to the first combustion chamber roof. The combustion chamber is, for example, partially bounded by the cylinder, partially by the piston, and partially by the combustion chamber roof. During the firing operation of the internal combustion engine, a combustion process takes place within each operating cycle of the engine, in particular at least or exactly one. In each combustion process, a fuel-air mixture, also simply called a mixture, is burned, which comprises air and a fuel, for example, in the form of a liquid or gaseous fuel. The air is also referred to as combustion air or fresh air. Most preferably, the internal combustion engine is designed as a spark-ignition engine and thus, for example, as a gasoline engine. The internal combustion engine, for example, has an output shaft which is rotatable about an output shaft axis relative to the housing elements. For example, the output shaft is rotatable about the output shaft axis relative to the housing elements at the The engine block is mounted. In particular, the output shaft is a crankshaft. The piston is articulated to the output shaft via a connecting rod, so that the translational movements of the piston relative to the housing elements and within the cylinder are converted into a rotational movement of the output shaft, which thereby rotates about its axis of rotation relative to the housing elements. In particular, the combustion process can drive the piston and, via the connecting rod, the output shaft, causing the output shaft to rotate about its axis of rotation relative to the housing elements. This allows the internal combustion engine to provide a drive torque for propelling the motor vehicle. Preferably, the internal combustion engine is a four-stroke engine, such that each operating cycle of the internal combustion engine comprises, in particular, exactly two complete revolutions of the output shaft, and in particular, exactly, 720 degrees of crankshaft angle.

For example, the gas exchange valve is associated with a gas channel, which is also referred to as the first gas channel. Whenever the gas channel is mentioned before and after, this refers to the first gas channel unless otherwise specified. The gas channel, particularly when the gas exchange valve is open, is permeable to gas. In the closed position of the gas exchange valve, the gas channel is fluidically blocked and thus fluidically separated from the combustion chamber, preventing, for example, gas from flowing out of the gas channel and into the combustion chamber, or vice versa. In the open position, the gas exchange valve releases the gas channel, thus fluidly connecting it to the combustion chamber. Therefore, in the open position, gas can flow out of the gas channel and into the combustion chamber, or vice versa. In particular, if the gas exchange valve is an intake valve, the gas channel is an intake channel through which air can be introduced into the combustion chamber, so that the aforementioned gas is then air. In particular, if the gas exchange valve is an exhaust valve, the gas channel is an exhaust channel, so that in the open position, gas from the combustion chamber can be introduced into the exhaust channel and thus discharged from the combustion chamber. Then the gas is exhaust gas from the internal combustion engine, the exhaust gas resulting from the respective combustion process, that is, produced by the respective combustion process. Most importantly, the gas exchange valve is translationally movable relative to the housing elements between the open and closed positions.

For example, an electronic computing device, also referred to as a control unit or at least comprising a control unit, is provided for, by means of which the procedure is carried out.

To achieve a particularly advantageous operation of the internal combustion engine, the invention provides that, in a first embodiment, structure-borne sound from the internal combustion engine is measured by means of a structure-borne sound sensor, and a structure-borne sound signal, in particular an electrical signal, is provided that characterizes the structure-borne sound measured by the sensor. Alternatively or additionally, that is, in a second embodiment provided as an alternative or in addition to the first embodiment, a pressure sensor measures the pressure prevailing in the combustion chamber, and an electrical pressure signal is provided that characterizes the pressure measured by the pressure sensor. The structure-borne sound signal and the pressure signal are collectively referred to as signals. In particular, the respective signal is or characterizes a temporal profile of the structure-borne sound or the pressure prevailing in the combustion chamber. In particular, the structure-borne sound is structure-borne sound occurring during the respective operating cycle. Preferably, the pressure, also referred to as combustion chamber pressure, is a pressure occurring, that is, prevailing, in the combustion chamber during the respective operating cycle. Preferably, the structure-borne sound is measured, i.e., recorded, by means of the structure-borne sound sensor during the respective operating cycle. Preferably, the pressure prevailing, i.e., occurring, in the combustion chamber is measured, i.e., recorded, by means of the pressure sensor during the respective operating cycle. Thus, the structure-borne sound is preferably structure-borne sound occurring during the respective operating cycle. Furthermore, the pressure is, for example, pressure prevailing, i.e., occurring, in the combustion chamber during the respective operating cycle. Therefore, it is preferably provided that the signal is a time course of the structure-borne sound occurring during the respective operating cycle, or of the pressure prevailing or occurring in the combustion chamber during the respective operating cycle, or that the signal characterizes or comprises a time course of the structure-borne sound occurring during the respective operating cycle, or of the pressure prevailing, i.e., occurring, in the combustion chamber during the respective operating cycle.

In the method according to the invention, at least one value is determined based on the structure-borne sound signal and/or the pressure signal. This value characterizes a point in time, also referred to as the closing time, at which the gas exchange valve reaches the closed position within at least one of the operating cycles of the internal combustion engine, in particular by moving the gas exchange valve from the closed position to the open position within that at least one operating cycle. In other words, if, particularly in the first variant, the structure-borne sound is detected by means of the structure-borne sound sensor and the structure-borne sound signal is provided, the value also referred to as the closing value is determined based on the structure-borne sound signal. Alternatively or additionally, particularly in the second variant, if the pressure, also referred to as the combustion chamber pressure, is measured by means of the pressure sensor and the pressure signal is provided, the value also referred to as the closing value is determined based on the pressure signal.

The characteristic that the gas exchange valve reaches the closed position at a certain point in time within at least one operating cycle means that the gas exchange valve moves from the closed position to the open position and then back from the open position to the closed position within at least one operating cycle, thus reaching the closed position at the point in time also referred to as the closing time. When the term "time" is used before and after, it refers to the closing time unless otherwise specified. Within each operating cycle, and thus within at least one operating cycle, the gas exchange valve begins its movement from the closed position to the open position at an opening time. Within each operating cycle, and thus within at least one operating cycle, the gas exchange valve, after beginning its movement from the closed position to the open position, reaches the closed position again at the closing time following the opening time. In the closed position, the gas exchange valve sits, for example, on a corresponding valve seat, particularly on the second housing element, so that, for example, the gas exchange valve directly contacts the valve seat in the closed position. At the opening point, within each operating cycle (and thus within at least one operating cycle), the gas exchange valve begins to lift off the valve seat, as its movement from the closed to the open position begins at that point. During this movement, the gas exchange valve moves away from the valve seat. After reaching the open position within the operating cycle, the gas exchange valve moves back to the closed position. During this movement, the gas exchange valve moves towards the valve seat and reaches it at the closing point, thus resting on the valve seat. The closing point coincides with the rotational position of the output shaft. This means that the output shaft is in the specified rotational position at the closing point. If the gas exchange valve is the aforementioned inlet valve, the closing point is also referred to as inlet closes (IS), and the opening point is also referred to as inlet opens (EE). If the gas exchange valve is the aforementioned exhaust valve, the closing point is also referred to as exhaust closes (AS), and the opening point is also referred to as exhaust opens (EE).

In this method, the internal combustion engine is operated, particularly by means of the electronic computing device, depending on the determined value. This allows, for example, variations in the value or the closing time, especially those caused by wear, to be compensated for, thus ensuring particularly advantageous, and in particular, low-emission and fuel-consumption and/or efficient, operation of the internal combustion engine. In other words, if, for example, the actual value deviates from a target value or reference value, such that, for example, the actual closing time deviates from a target closing time or reference point, the internal combustion engine can be operated depending on the value in such a way that this deviation is compensated for and/or at least reduced, in particular eliminated. Alternatively or additionally, the value-dependent operation of the internal combustion engine can, for example, include operating at least one component depending on the value, in particular to compensate for the deviation described above.

The invention is based in particular on the following findings and considerations: Due to tolerances, for example in a control drive, especially one designed as a chain drive, by which, for example, the gas exchange valve can be actuated by the output shaft and thus moved relative to the housing element, tolerances of an actuator for varying the valve timing of the gas exchange valve, incorrect assembly and/or elongation of a traction element, for example designed as a chain, which occurs with increasing service life and/or operating time of the internal combustion engine, can lead to problems. Due to the timing drive, deviations can occur such that, for example, the actual opening time (actual opening time) deviates from a target opening time or reference time, and the actual closing time within the respective operating cycle deviates from a target closing time or reference closing time, particularly excessively. Depending on the magnitude of the respective deviation, this can result in increased fuel consumption, increased emissions, or other undesirable effects such as significantly elevated exhaust gas temperatures. The invention now makes it possible to determine any deviation of the actual value from a side value or reference value, and thus any deviation of the actual closing time from a target closing time or reference closing time, and subsequently to compensate for this by operating the internal combustion engine according to the increased value, in particular to the extent that the deviation is at least reduced or eliminated. The contact of the gas exchange valve with the valve seat can be detected based on the respective signal, with this contact point, or rather the time of contact, being characterized by the value. This value thus provides information about possible assembly errors, wear, and/or malfunctions in the timing drive. For example, a comparison is performed, particularly using the electronic processing unit, in which the determined value is compared to a target value. If, for example, the comparison reveals that a deviation of the actual value from the target value exceeds a predefined threshold, then the internal combustion engine is subsequently operated according to the actual value, thereby initiating at least one correction or measure to reduce or eliminate the deviation. Furthermore, it is conceivable that, depending on the measured value, a warning signal, perceptible acoustically, visually, and/or haptically to a person inside the vehicle, is emitted by means of a display device, particularly an electrical or electronic one, especially located in the vehicle's interior. This signal alerts the person to the measured value or to the deviation of the actual value from the target value. The warning signal could, for example, prompt the person to carry out repairs or maintenance on the vehicle, particularly the internal combustion engine, whereby the repair or maintenance could at least reduce or eliminate the deviation.

It was found that a short, and in particular, varying amplitude of the signal is characteristic of the closing of the gas exchange valve, depending on the engine speed. In other words, when the gas exchange valve reaches the closed position, i.e., at the closing point, a short, and in particular, varying amplitude of the signal occurs, causing the signal to exceed a predefined or predetermined signal threshold. Thus, the time characterized by the value is, for example, the point in time at which the signal exceeds the signal threshold. To determine this time and therefore the value particularly advantageously, a time derivative of the signal is calculated, for example, using an electronic computing device. Since the closing position of the gas exchange valve causes the aforementioned oscillation of the signal, this also leads to an oscillation in the time derivative. In other words, the closing position of the gas exchange valve also affects the time derivative, for example, by causing the time derivative to exceed the signal threshold or a predefined limit value. Thus, the point in time at which the time derivative exceeds the signal threshold and/or the limit value is a specific time. Exceeding the signal threshold or limit value by the signal or by the time derivative is also referred to as threshold exceedance, which occurs at that specific time. Therefore, the value characterizes the time of threshold exceedance. Threshold exceedance is equivalent to the gas exchange valve coming into contact with the valve seat. In other words, the point in time when the threshold is exceeded is equivalent to the point in time when the gas exchange valve sits on the valve seat and thus reaches the closed position.

For example, a target value for the timing and an opening duration of the gas exchange valve, which is open continuously during the respective working cycle, can be used to define, for example, a crank angle range. The time range in which, for example, the structure-borne sound or pressure is measured and/or the signal is evaluated in order to determine the value, can be limited in order to keep the computation time required for determining the value advantageously low.

To operate the internal combustion engine particularly efficiently, one embodiment of the invention provides that, for several successive operating cycles of the internal combustion engine, at least one value is determined based on the structure-borne sound signal and/or the pressure signal. This value characterizes a specific point in time at which the gas exchange valve reaches the closed position within the respective operating cycle of the internal combustion engine. A mean value, particularly a moving average, is calculated from these values, and the internal combustion engine is operated according to this mean value. This allows any measurement errors and/or inaccuracies in the measurements of structure-borne sound or pressure to be compensated for, thus enabling particularly precise determination of any deviations of the closing time from a target time or reference time.

In a further embodiment of the invention, the internal combustion engine has at least two combustion chambers, namely the first combustion chamber to which the first gas exchange valve is assigned, and a second combustion chamber to which at least a second gas exchange valve is assigned. The preceding and following descriptions relating to the first combustion chamber can readily be applied to the second combustion chamber, and vice versa.

The second gas exchange valve is moved from a second closed position to a second open position and from the second open position back to the second closed position during the respective working cycle of the internal combustion engine.

To enable particularly advantageous operation of the internal combustion engine, a further embodiment of the invention provides that at least a second value is determined based on the structure-borne sound signal and/or outside the pressure signal. This second value characterizes the point in time at which the second gas exchange valve reaches its second closed position within at least one of the combustion engine's operating cycles. The internal combustion engine is then operated based on this second value. To compensate for any deviations between actual and target values, for example, those caused by wear or tolerances, not only the first combustion chamber and the first gas exchange valve, but also the second combustion chamber and the second gas exchange valve are taken into account. This allows for particularly advantageous operation of the internal combustion engine, especially with low emissions and fuel consumption.

Another embodiment is characterized in that a second structure-borne sound from the internal combustion engine is measured by means of an additional structure-borne sound sensor, and a structure-borne sound sensor signal characterizing the measured second structure-borne sound is provided. Alternatively or additionally, a second pressure sensor measures a second pressure prevailing in the second combustion chamber and provides a pressure sensor signal characterizing the measured second pressure. The preceding and following descriptions of the first structure-borne sound sensor, the first structure-borne sound, and the structure-borne sound signal can readily be applied to the second structure-borne sound sensor, the second structure-borne sound, and the structure-borne sound sensor signal, and vice versa. Accordingly, the preceding and following descriptions of the first pressure sensor, the first pressure, and the pressure signal can readily be applied to the second pressure sensor, the second pressure, and the pressure sensor signal, and vice versa.

If the structure-borne sound sensor signal is provided, at least one signal value is determined from this signal, characterizing the point in time at which the second gas exchange valve reaches its second closed position within at least one of the operating cycles. Alternatively or additionally, if the pressure sensor signal is provided, the signal value is determined from this signal. The preceding and following explanations regarding the value can readily be applied to the signal value and vice versa. Similarly, the preceding and following explanations regarding the point in time at which the first gas exchange valve reaches its closed position can readily be applied to the point in time at which the second gas exchange valve reaches its second closed position and vice versa. It is preferably provided that the internal combustion engine is operated based on the determined signal value, thereby compensating for any deviations due to tolerances and/or wear. Consequently, a particularly advantageous, especially a special, This will enable the operation of the internal combustion engine to be realized with lower emissions and fuel consumption.

In order to achieve a particularly advantageous operation of the internal combustion engine, a further embodiment of the invention provides that the structure-borne sound signal and/or the pressure signal is also used to implement knock control of the internal combustion engine. This allows the method to be implemented particularly cost-effectively.

In order to carry out the process particularly advantageously and thus achieve a particularly advantageous operation of the internal combustion engine, it is further provided in the invention that the structure-borne sound sensor signal and/or the pressure sensor signal is also used to carry out the knock control of the internal combustion engine.

In a further embodiment of the invention, the gas exchange valve is the aforementioned inlet valve. Any deviations can be advantageously detected using the inlet valve, thereby enabling advantageous operation.

To achieve a particularly advantageous, especially low-emission and fuel-consumption, operation of the internal combustion engine, a further embodiment of the invention provides for the internal combustion engine to be operated according to the Miller cycle. Since the internal combustion engine is preferably designed as a four-stroke engine, each operating cycle of the internal combustion engine comprises, in particular, exactly four strokes. The first of these strokes is an intake stroke. A second stroke, following the first, is a compression stroke. A third stroke, following the second, is a power stroke. A fourth stroke, following the third, is an exhaust stroke, in which the exhaust gas is expelled from the combustion chamber, in particular by means of the piston, and especially by the piston moving from its bottom dead center to its top dead center. During the intake stroke, the piston moves from top dead center to bottom dead center, and air is drawn into the combustion chamber. During the compression stroke, the mixture is compressed. In the power stroke, the mixture expands due to ignition and combustion, thereby driving the piston. The Miller cycle is characterized in particular by the fact that the intake valve closes very early, specifically to the point that it closes and reaches the closed position during the first stroke (intake stroke). This allows for particularly efficient operation.

A second aspect of the invention relates to an internal combustion engine for a motor vehicle, wherein the internal combustion engine is configured to carry out a method according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention and vice versa.

• 1 eine schematische Darstellung einer Verbrennungskraftmaschine eines Kraftfahrzeugs.

Further details of the invention will become apparent from the following description of preferred embodiments with the accompanying drawing. The only one shown is...

• 1 A schematic representation of an internal combustion engine of a motor vehicle.

1 Figure 1 shows a schematic representation of an internal combustion engine (also called a combustion engine or internal combustion power unit) of a motor vehicle (also simply called a vehicle). Based on 1 A method for operating the internal combustion engine 1 is described, wherein the method is carried out, for example, by means of an electronic computing device 17. In the method, the internal combustion engine has at least two combustion chambers, namely a first combustion chamber 4a and a second combustion chamber 4b. The respective combustion chamber 4a, b is partially formed by a respective cylinder 3a, b of the internal combustion engine 1. The cylinders 3a and 3b are formed by an engine block 2 of the internal combustion engine 1, wherein the engine block 2 is, for example, a cylinder housing, in particular a cylinder crankcase, of the internal combustion engine 1. The internal combustion engine 1 also has an output shaft 5, for example, designed as a crankshaft, which is rotatable about an output shaft axis of rotation relative to the engine block 2. In the respective cylinder 3a, b, a respective piston is arranged to be translationally movable, such that the respective piston is translationally movable relative to the engine block 2 and thus can be moved back and forth. The combustion chamber 4a is partially limited by the piston located in cylinder 3a, and the combustion chamber 4b is partially limited by the piston located in cylinder 3b. Furthermore, each combustion chamber 4a, b is partially limited by its respective installation space requirements. The engine block 2 is a first housing element of the internal combustion engine 1. The internal combustion engine 1 has a 1 second housing element (not shown), which is separate from The second housing element is formed by and connected to the first housing element. For example, the second housing element is a cylinder head. The combustion chamber roofs are formed by the second housing element. For example, the method is carried out while the motor vehicle is in motion, in whose interior at least one person, such as the driver, can be located during the journey. In particular, the method is carried out while the internal combustion engine 1 is running. Specifically, the method is carried out while the motor vehicle is being driven by the internal combustion engine 1, particularly in this running mode. During the method, the internal combustion engine 1 performs work cycles, such that the engine 1 executes these work cycles. The work cycles follow one another in time. In particular, each work cycle comprises exactly two complete revolutions of the output shaft 5 and thus exactly 720 degrees of crankshaft angle. Within each work cycle, a mixture is ignited and combusted in the respective combustion chamber 4a, b. The mixture consists of air, also known as fresh air or combustion air, and a fuel, for example, in liquid or gaseous form. The combustion of this mixture produces exhaust gas from the internal combustion engine 1. The combustion of this mixture drives the respective piston, which partially defines the combustion chamber 4a, b. Each piston is articulated to the output shaft 5 via a connecting rod. Driving the piston drives the output shaft 5, causing it to rotate around its axis of rotation relative to the respective housing element. This allows the internal combustion engine 1 to provide drive torque to propel the vehicle via the output shaft 5. Specifically, the internal combustion engine 1 is a four-stroke engine. In particular, the internal combustion engine 1 is a reciprocating engine.

Each combustion chamber 4a, b is assigned, in particular, two inlet valves 11, wherein air can be introduced into the respective combustion chamber 4a, b via the respective inlet valve 11 or is introduced within the respective working cycle. Furthermore, each combustion chamber 4a, b is assigned, for example, in particular, two in 1 The exhaust valves (not shown) are assigned to the respective exhaust valves. Exhaust gas from the respective combustion chamber 4a, b can be discharged via the respective exhaust valve. The intake valves 11 and the exhaust valves are gas exchange valves of the internal combustion engine 1. During the respective operating cycle of the internal combustion engine 1, the respective gas exchange valve moves from a closed position to an open position and then, after being moved to its open position, back to its closed position. Specifically, the respective gas exchange valve is translationally movable relative to its housing between its closed and open positions. Each gas exchange valve is assigned a valve seat, which is formed, for example, by a second housing element.

The procedure is described below using the respective inlet valve 11 as an example. The preceding and following explanations regarding the respective inlet valve 11 can readily be applied to the respective exhaust valve and vice versa. At a point in time occurring within the respective operating cycle, also referred to as the closing point, at which the respective inlet valve 11 reaches its respective closed position within the respective operating cycle, particularly after the respective inlet valve 11 has moved from its respective closed position to its respective open position within the respective operating cycle, the respective inlet valve 11 comes to rest on its respective, assigned valve seat; thus, the respective inlet valve 11 reaches its respective, assigned valve seat. The closing point at which each inlet valve 11 reaches its respective closed position within the respective operating cycle, after having moved from its respective closed position to its respective open position within the respective operating cycle, coincides with a respective rotational position of the output shaft 5, such that the output shaft 5 assumes the aforementioned rotational position at the closing point. The closing point and the rotational position are also referred to as inlet closes (IS).

The internal combustion engine 1 also has an intake tract 21, also referred to as the intake stroke, through which the aforementioned air flows and by means of which the air is directed to and into the combustion chambers 4a and 4b. The internal combustion engine 1 also has an exhaust tract 22, into which the exhaust gas can be introduced via the respective exhaust valve from the respective combustion chambers 4a and 4b. Therefore, the exhaust tract 22 is permeable to the exhaust gas. The internal combustion engine 1 also has an exhaust gas turbocharger. The exhaust gas turbocharger 23 comprises a turbine 24 with a turbine wheel 12 arranged in the exhaust tract 22. The turbine wheel 12 can be driven by the exhaust gas flowing through the exhaust tract 22. The exhaust gas turbocharger 23 also has a compressor 25 with a compressor wheel 13 arranged in the exhaust tract 22. The compressor wheel 13 can be driven by the turbine wheel 12 via a shaft 14 of the exhaust gas turbocharger 23 and is thus rotatable, whereby the air flowing through the inlet tract 21 is compressed by means of the compressor wheel 13, and is thus compressed by driving and thus rotating the compressor wheel 13.

The internal combustion engine 1 also features a 1 The process involves the schematically depicted sensor 15, by means of which a measured quantity is measured, i.e., recorded, during the process and especially during the respective operating cycle of the internal combustion engine 1. Furthermore, the sensor 15 provides a signal, in particular an electrical signal, that characterizes the measured quantity. For example, the sensor 15 is a structure-borne sound sensor, such that the measured quantity is or characterizes structure-borne sound from the internal combustion engine 1. Thus, for example, during the process and especially during the respective operating cycle of the internal combustion engine 1, the structure-borne sound from the internal combustion engine 1, in particular from the engine block 2, is measured, i.e., recorded, by means of the structure-borne sound sensor. The signal is therefore, for example, a structure-borne sound signal that characterizes the measured, i.e., recorded, structure-borne sound. Furthermore, it is conceivable that the sensor 15 is a pressure sensor, wherein the measured quantity is, for example, the pressure prevailing, i.e., occurring, in the combustion chamber 4a or 4b during the process and, in particular, during the respective operating cycle, also referred to as combustion chamber pressure, so that, for example, the pressure sensor measures the pressure prevailing, i.e., occurring, in the combustion chamber 4a or 4b, particularly during the process and especially during the respective operating cycle. Thus, for example, the signal is a pressure signal that characterizes the pressure (combustion chamber pressure) measured by the pressure sensor and prevailing, i.e., occurring, in the combustion chamber 4a, b during the process, particularly within the respective operating cycle.

In this method, the electronic computing device 17 uses the signal to determine at least one value, also referred to as a time value, which characterizes the aforementioned closing time at which the respective inlet valve 11 reaches its closed position within at least one of the operating cycles of the internal combustion engine 1. In particular, the measured quantity is recorded by the sensor 15 during this at least one operating cycle. The internal combustion engine 1 is operated according to the determined time value. For example, the electronic computing device 17 performs a comparison in which the determined value is compared with a target value. If, for example, the comparison reveals that a deviation of the actual value from the target value exceeds a predefined or predetermined threshold, the internal combustion engine 1 is operated according to this deviation using the electronic computing device 17. Operating the internal combustion engine 1 in a deviation-dependent manner includes, for example, operating the internal combustion engine 1 in such a way that the deviation is at least reduced or eliminated.

For example, a time derivative of the signal is calculated using the electronic computing device 17. This time derivative is then analyzed by the electronic computing device 17 to determine, for example, whether it exceeds a predefined or predetermined signal threshold. Specifically, by analyzing the signal or its time derivative, the electronic computing device 17 determines a point in time, also known as the threshold time, at which the time derivative exceeds the signal threshold. This threshold time is then used as the closing time. In other words, the threshold time is the closing time. The underlying principle is that when the inlet valve 11 reaches its valve seat at the closing time, this movement causes the signal to oscillate, causing the time derivative of the signal to exceed the signal threshold. Therefore, by determining the threshold time, the closing time can be identified.

Reference symbol list

1

internal combustion engine

2

Engine block

3a, b

cylinder

4a, b

combustion chamber

5

Output shaft

11

Inlet valve

12

Turbine wheel

13

compressor wheel

14

Wave

15

sensor

17

electronic computing device

21

Entrance area

22

exhaust system

23

Exhaust gas turbocharger

24

turbine

25

compressor

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• JP 2013-29076 A [0002]
• US 10 161 334 B2 [0002]
• JP 5928354 B2 [0002]
• DE 10 2014 010 454 A1 [0002]

Claims (10)

A method for operating an internal combustion engine (1) of a motor vehicle, in which the internal combustion engine (1) has at least one combustion chamber (4a) to which at least one gas exchange valve is assigned, which is moved from a closed position to an open position and from the open position back to the closed position within each operating cycle of the internal combustion engine (1), characterized in that: - structure-borne sound of the internal combustion engine (1) is measured by means of a structure-borne sound sensor and a structure-borne sound signal characterizing the measured structure-borne sound is provided and/or a pressure prevailing in the combustion chamber (4a) is measured by means of a pressure sensor and a pressure signal characterizing the measured pressure is provided; - at least one value is determined on the basis of the structure-borne sound signal and/or on the basis of the pressure signal which characterizes a time at which the gas exchange valve reaches the closed position within at least one of the operating cycles of the internal combustion engine (1); and - the internal combustion engine (1) is operated depending on the determined value. Procedure according to Claim 1 , characterized in that for several successive operating cycles of the internal combustion engine (1) at least one respective value is determined on the basis of the structure-borne sound signal and/or on the basis of the pressure signal, which characterizes a respective time at which the gas exchange valve reaches the closed position within the respective operating cycle of the internal combustion engine (1), wherein an average value is calculated from the values, and wherein the internal combustion engine (1) is operated depending on the average value. Procedure according to Claim 1 or 2 , characterized in that the internal combustion engine (1) has at least two combustion chambers (4a, 4b), namely the at least one combustion chamber (4a) as the first combustion chamber (4a), to which the at least one gas exchange valve is assigned as the first gas exchange valve, and a second combustion chamber (4b), to which at least one second gas exchange valve is assigned, which is moved within the respective working cycle of the internal combustion engine (1) from a second closed position to a second open position and from the second open position back to the second closed position. Procedure according to Claim 3 , characterized in that at least a second value is determined on the basis of the structure-borne sound signal and/or on the basis of the pressure signal, which characterizes a time at which the second gas exchange valve reaches the second closed position within at least one of the working cycles of the internal combustion engine (1), wherein the internal combustion engine (1) is operated depending on the second value. Procedure according to Claim 3 or 4 , characterized in that: - a second structure-borne sound of the internal combustion engine (1) is measured by means of a second structure-borne sound sensor and a structure-borne sound sensor signal characterizing the measured second structure-borne sound is provided and/or a second pressure prevailing in the second combustion chamber (4b) is measured by means of a second pressure sensor and a pressure sensor signal characterizing the measured second pressure is provided; - at least one signal value is determined on the basis of the structure-borne sound sensor signal and/or on the basis of the pressure sensor signal, which characterizes a time at which the second gas exchange valve reaches the second closed position within at least one of the working cycles of the internal combustion engine (1); and - the internal combustion engine (1) is operated depending on the determined signal value. Method according to one of the preceding claims, characterized in that the structure-borne sound signal and/or the pressure signal is used to perform knock control of the internal combustion engine (1). Procedures according to the Claims 5 and 6 , characterized in that the structure-borne sound sensor signal and/or the pressure sensor signal is used to perform the knock control of the internal combustion engine (1). Method according to one of the preceding claims, characterized in that the gas exchange valve is an inlet valve (11). Method according to one of the preceding claims, characterized in that the internal combustion engine (1) is operated according to the Miller process. Internal combustion engine (1) for a motor vehicle, wherein the internal combustion engine (1) is designed to carry out a method according to one of the preceding claims.