Internal combustion engine, method for operating the same and motor vehicle with such an internal combustion engine

Abstract

Internal combustion engine with a crankcase ventilation system (23), comprising a crankcase (17), an intake air line (2), wherein the intake air line (2) comprises a throttle valve (6) and an air filter (8), and with a crankcase ventilation line (4) for ventilating the crankcase (17) and a crankcase ventilation line (3) for flushing the crankcase (17), wherein the crankcase ventilation line (4) is arranged at a first connection point (13, 70) downstream of the air filter (8) to the intake air line (2), characterized in that a sensor unit (18) is arranged in the crankcase ventilation line (3) downstream of a first flow influencing device (7) and upstream of a first backflow prevention device (26), wherein the first connection point (13, 70) is spaced downstream from a crankcase ventilation line connection (28) is arranged on the intake air line (2),such that a malfunction of the crankcase ventilation system (23) can be detected by the sensor unit (18), wherein a turbocharger (5) is arranged downstream of the first connection point (13, 70) and upstream of the throttle valve (6), wherein the turbocharger (5) and the throttle valve (6) are arranged between the first connection point (13, 70) and a second connection point (15, 80), wherein the second connection point (15, 80) is arranged on the intake air line (2), wherein the crankcase ventilation line (4) comprises a crankcase ventilation line branch (21) and a pressure control unit (22), wherein the pressure control unit (22) is arranged upstream of the crankcase ventilation line branch (21).

Description

The invention relates to an internal combustion engine which has a crankcase ventilation and a crankcase ventilation, wherein these can be checked for their proper function. If an incorrect state is detected, a measure is triggered.Internal combustion engines which are designed as reciprocating piston engines have, for structural reasons, a piston with one or more piston rings. This piston is connected to a crankshaft via a connecting rod. The piston itself runs up and down in the combustion chamber, i.e. the cylinder. The cylinder and crankshaft are enclosed in a crankcase. During the combustion process, combustion gases are discharged from the combustion chamber into the crankcase due to the gap between piston rings and cylinders and the pressure drop prevailing in the combustion chamber toward the crankcase. The escape of these combustible gases from the crankcase is legally prohibited in most countries of the world, since these combustible gases contribute to air pollution. Most legislation further prescribe that the integrity of the crankcase ventilation system is to be checked at regular intervals. Regularly, it is often understood that a check takes place in the case of typically occurring operating states. In order to prevent the combustible gases from being discharged from the crankcase, fresh air is used to flush the crankcase. Fresh air is directed through the crankcase where it mixes with the fuel gases. This mixture of fuel gas and fresh air is conducted through the crankcase ventilation line to the intake air line. There, the mixture mixes with the air in the intake air line and is thus supplied to the combustion chamber, so that the combustion gases are burned there. It must therefore be ensured that the crankcase is always safely flushed and both the crankcase and the crankcase ventilation line are intact. If there is a malfunction or an improper state of the crankcase, crankcase ventilation line or crankcase ventilation line, then combustible gases can reach the environment. Monitoring of the integrity of the crankcase ventilation system, consisting of crankcase ventilation line and crankcase ventilation line, is therefore required. The monitoring system extends to the crankcase ventilation line, its connection to the intake air line, the backflow prevention devices possibly arranged there, and the tightness of the crankcase ventilation line itself. The same applies to the crankcase ventilation line and the crankcase itself.DE 10 2009 008 831 A1 relates to an internal combustion engine having an intake air line which contains a compressor of an exhaust gas turbocharger and a throttle valve, and having a tank venting system and a crankcase venting system which are connected to the intake air line at two connection points upstream of the compressor and downstream of the throttle valve. In order to enable monitoring of the introduction points of the venting gases into the intake air line in a relatively simple manner, it is proposed that a check valve be arranged directly at the connection points. A separate crankcase ventilation line, serving only for ventilating the crankcase, is not shown.US 2020 / 0 256 276 A1 discloses an internal combustion engine including on-off valves that configure a closed space by closing an interior of a vent line, a pump that pressurizes or vents the closed space, a pressure sensor that detects the pressure of the closed space, and an abnormality detection element that evaluates the abnormality of the vent line. The abnormality detection element evaluates the abnormality of the air vent line based on a pressure change of the closed space in a case where the closed space is pressurized or air-vented by the pump.DE 10 2017 222 770 A1 relates to a method for operating a crankcase ventilation device of an internal combustion engine for a motor vehicle, in which at least one flow cross section, through which a fluid can flow from a crankcase of the internal combustion engine, of a ventilation line of the crankcase ventilation device, through which the fluid can flow is set by means of at least one valve element arranged in the ventilation line, wherein the flow cross section is regulated and thereby set by means of the valve element as a function of at least one engine load- and / or engine speed-dependent variable.DE 10 2015 116 483 B4 relates to a method for an engine, comprising: indicating an integrity break of a crankcase ventilation system based on an integral value of actual pressure in a crankcase ventilation pipe over a period of a transition engine air flow relative to an integral value of expected pressure in the crankcase ventilation pipe over the period of time.DE 10 2022 104 194 A1 discloses methods and systems for diagnosing a clogged crankcase and for performing a crankcase cleaning. In one example, a method of operating an engine system including an engine includes measuring a crankcase pressure and, responsive to the crankcase pressure increasing above a threshold pressure, determining a position of a clogged oil separator in a crankcase, and directing fluid to flow through the clogged oil separator and into the crankcase until a flow rate of the fluid through the clogged oil separator and into the crankcase increases above a threshold flow rate.US 5 792 949 A discloses a positive crankcase ventilation diagnostic system applied in an automotive internal combustion engine with a pressure sensor located in the system for continuously sensing system pressure while the engine is running in the steady state operation. The minimum and maximum sensed pressure values are stored during each of the repeated test periods. Pressure values exceeding a predetermined normal range beyond at least one test period indicate a leak or constraint condition in the system. Small differences in the pressure values over the test periods indicate sensor or electrical fault conditions. Fault conditions are logged and displayed when they are persistent.It is therefore an object of the present invention to disclose an apparatus and a method by means of which the integrity of the crankcase ventilation system can be diagnosed more robust and reliable.This object is achieved by the subject matters of the independent claims. Advantageous embodiments and developments are the subject matter of the dependent claims. To achieve the object, an internal combustion engine is proposed having a crankcase ventilation system comprising a crankcase, an intake air line, the intake air line comprising a throttle valve and an air filter, and having a crankcase ventilation line for ventilating the crankcase and a crankcase ventilation line for scavenging the crankcase, the crankcase ventilation line being arranged at at least one first connection point downstream of the air filter to the intake air line, wherein a sensor unit is arranged in the crankcase ventilation line downstream of a first throughflow influencing device and upstream of a first backflow prevention device, wherein the first connection point is arranged downstream spaced apart from a crankcase ventilation line connection on the intake air line, such that a malfunction of the crankcase ventilation system can be detected by the sensor unit, wherein a turbocharger is arranged downstream of the first connection point and upstream of the throttle valve, wherein the turbochargers and the throttle valve are arranged between the first connection point and a second connection point, wherein the second connection point is arranged on the intake air line, wherein the crankcase ventilation line comprises a crankcase ventilation line branch and a pressure regulating unit, wherein the pressure regulating unit is arranged upstream of the crankcase ventilation line branch.The proposed internal combustion engine enables operation in the non-boosted state and in its developments in the boosted state. The internal combustion engine thus forms the basis for its developments. The proposed internal combustion engine enables the reliable diagnosis of the integrity of the crankcase ventilation system using a probe in the crankcase ventilation device. Furthermore, the proposed internal combustion engine enables a crankcase ventilation line which serves solely for ventilating the crankcase. Thus, in a proper state, the probe will never be exposed to combustible gases. This means that the probe is not exposed to a corrosive environment and can therefore be manufactured from less demanding materials. Thus, in the event of a leak in the crankcase ventilation line, no combustion gas escapes into the environment either. Due to the arrangement of the probe in the crankcase ventilation line, it has proven to be advantageous that the probe is not exposed to high temperatures, so that it can be manufactured from less demanding materials. Furthermore, compensation for temperature variations is necessary to a lesser extent than if it were flushed with combustible gases.In the internal combustion engine, a turbocharger is furthermore arranged downstream of the first connection point and upstream of the throttle flap.The arrangement of a turbocharger may enable such a boosted state. Depending on the driving state, operation may be performed in the charged state or in the non-charged state. As a result, several states of the internal combustion engine can stand for selection. In all of these conditions, crankcase ventilation system integrity may be diagnosed.In the internal combustion engine, the turbocharger and the throttle valve are further arranged between the first connection point and a second connection point, the second connection point being arranged on the intake air line.This arrangement enables the integrity of the crankcase ventilation system to be tested in a robust manner. Due to the arrangement of the turbocharger and the throttle valve between the first and the second connection point, a negative pressure is established in the intake air line downstream of the throttle valve. As a result of this negative pressure, the combustion gases are supplied from the crankcase to the intake air line through the crankcase ventilation line and are supplied to the combustion chamber.In the internal combustion engine, in which the crankcase ventilation line comprises a crankcase ventilation line branch and a pressure regulating unit, the pressure regulating unit is arranged upstream of the crankcase ventilation line branch.It has been found to be advantageous for a pressure regulating unit to be arranged in the crankcase ventilation line upstream of the crankcase ventilation line branch. This pressure regulating unit can be configured to set a negative pressure in the crankcase. This negative pressure can be set in such a way that sufficient combustion gases are discharged from the crankcase without an excess of combustion gas being drawn from the combustion chamber past the piston rings into the crankcase by the pressure drop in the crankcase. As a result, the motor efficiency can be increased and the load on the oil separator can be reduced. Furthermore, the amount of fuel gases supplying unburned and partially burned fuel and thus heating value, which is not taken into account in the injection amount, into the intake air line may be limited. This makes it possible to operate the internal combustion engine more uniformly.In a preferred embodiment of the internal combustion engine, a backflow prevention device is arranged upstream of the respective connection points of the crankcase ventilation line to the intake line.The backflow prevention devices can enable the targeted diagnosis in the case of an uncharged state and in the case of a recharged state. Depending on the state of the internal combustion engine, it may be determined which of the backflow prevention devices is not functioning properly. Furthermore, the integrity of the crankcase ventilation line can be established as a function of the operating state.In a preferred embodiment, the pressure control unit is configured to set a volume flow from the crankcase into the intake line, so that a predeterminable negative pressure in the crankcase is achieved in the best possible manner.The adaptation of the volume flow to a predeterminable negative pressure in the intake line can enable a better adaptation to the quantity of the combustible gases to be discharged from the crankcase. As a result, the internal combustion engine can be operated more efficiently. By adapting the negative pressure to the volume flow in the intake line, the design of the crankcase ventilation line can furthermore be carried out as required. This may allow advantages in terms of material usage and pressure loss in the crankcase ventilation line and the first line and the second line.In a preferred embodiment, the pressure regulating unit comprises an adjusting function and is connected to a computer unit for presetting a pressure to be set.By means of the actuating function of the pressure regulating unit, the pressure in the first line and in the second line and in the crankcase and the crankcase ventilation line can be designed to be selectively adjustable. The combustion gases can thereby be introduced in a manner adapted to the pressure level of the intake air line, in relation to the respective connection point and the respective operating state. The diagnosis of the operating state can be more robust by such an adaptation of the pressure level in the crankcase ventilation line and the first line and the second line. The use of a computer unit can make it possible to record the predetermined pressures to the pressure regulating unit. It can also record the data of the sensor unit. Furthermore, the computer unit can be connected to the sensor unit and can record the signals thereof. The computer unit can furthermore be connected at least to the control unit of the internal combustion engine. By detecting the operating state, the signal of the sensor and, if appropriate, the predefined and / or actual pressure of the pressure regulating unit in the crankcase ventilation line, the computer unit can determine a proper or an improper state. In other words, a diagnostic of the crankcase ventilation system may be performed. The computer unit can record the operating state, the signal of the sensor unit and the predeterminable pressure with a temporal assignment and store it in a memory. As a result, a diagnosis can be carried out subsequently in time if this was not possible at the actual time. As a result, a measure can be triggered.It has been found to be advantageous that the pressure predeterminable by the computer unit is operating point dependent.The specification of an operating point-dependent pressure in the crankcase ventilation line and thus in the crankcase can enable a robust diagnosis for each operating state of the internal combustion engine. Furthermore, the quantity of combustible gases that escape from the combustion chamber past the piston rings into the crankcase can be limited by the pressure in the crankcase ventilation line and the crankcase, which pressure is predefined as a function of the operating point. As a result, the efficiency of the internal combustion engine can increase. Further, the amount of fuel gases supplied to the intake air can be limited thereby, whereby more uniform operation of the internal combustion engine can be performed.To achieve the object, a method for operating an internal combustion engine is also used, comprising the following steps. The steps need not necessarily be performed in the order given. The following steps are carried out: detecting an operating state, detecting a signal of the sensor unit, determining a predefinable comparison value, ascertaining a difference between the detected signal of the sensor unit and the predefinable comparison value, ascertaining whether the ascertained difference exceeds or falls below a predefinable value, ascertaining a state on the basis of the exceeding or falling below the predefinable value, triggering at least one measure corresponding to the ascertained state.The detection of the operating state can be carried out simultaneously with the detection of the signal of the sensor unit. The detection of the operating state can take place with a time offset with the detection of the signal of the sensor unit. As long as the distances between two acquisitions are sufficiently small, a time-shifted acquisition can be carried out without problems. The comparison of the operating state, the detection of a signal of the sensor unit, the determination of a predefinable comparison value, the determination of a difference between the detected signal of the sensor unit and the predefinable comparison value can be carried out in direct temporal proximity to the detection or spaced apart in time. If a temporal spacing is to be present, then the values to be used for the method can be stored in a memory which can be accessed by the computer unit. The method may determine a state of the crankcase ventilation system. This condition may be proper or improper. An improper condition initiates a measure. A proper state does not trigger any measure. In particular, it may be determined whether a backflow prevention device is malfunctioning or whether a connection of the crankcase ventilation line or the crankcase ventilation line to the intake air line is not proper.For the solution, a method for operating the internal combustion engine as described above is proposed. In this method, the determination of the retention of the backflow prevention devices during the suction operation in the closed position, characterized in that D s-v corresponds to or substantially corresponds to or deviates from the permissible comparison value D z can be carried out.This method can be used to determine that combustion gases are not properly discharged from the crankcase. Further, it may be determined whether a backflow prevention device disposed in the crankcase ventilation line or the crankcase ventilation line is in a proper or improper state.A motor vehicle having an internal combustion engine as described above and operated according to the aforementioned method can be operated in such a way that, in the event of damage to the integrity of the crankcase ventilation system, in other words an improper state, emissions which are harmful to the environment and do not meet the regulations are prevented at an early stage.This disclosure contemplates the entirety of the crankcase ventilation line and crankcase ventilation line, as well as their respective connections to the crankcase, as a crankcase ventilation system.Within the scope of this disclosure, an internal combustion engine is understood to be an internal combustion engine according to the reciprocating piston principle, which may be ignited by a spark ignition and / or a self-ignition. Fuel may be supplied to the engine by either external and / or internal mixture formation. In one embodiment, it is provided that the internal combustion engine can be operated in a non-boosted state. In another embodiment, it is provided that, if a turbocharger is present, the internal combustion engine can be operated in a supercharged state. An uncharged state is present when the pressure in the intake air line downstream of the throttle valve corresponds to the ambient pressure or is below the ambient pressure. A boosted condition exists when the pressure in the intake air line downstream of the second pressure flow restriction device is above ambient pressure.Within the scope of this disclosure, the crankcase ventilation line connects the intake air line to the crankcase. Fresh air is supplied to the crankcase through the crankcase ventilation line. It is further understood that the crankcase ventilation line connects the crankcase to the intake air line. The crankcase ventilation line supplies the fuel gases mixed with the fresh air supplied and mixed with the crankcase ventilation line to the intake air line. For simplicity, this mixture of fuel gases and fresh air is referred to as fuel gases.It is obvious that a backflow prevention device can be, for example, either a check valve, in particular a diaphragm check valve or a ball check valve with or without a restoring device such as a spring, a check valve or a valve with actuator which is monitored by a correspondingly arranged measuring device and is controlled by this measuring device. Other types of backflow prevention devices are possible.It is understood within the scope of this disclosure that the flow or in the plurality of flows are to be understood as those gas flows which are conducted through the intake air line, the crankcase ventilation line and the crankcase ventilation line. This flow or these flows can be both volume flows and mass flows. The direction of flow in the intake air line is considered to lead to the combustion chamber. The flow direction of the crankcase ventilation line is considered to lead to the crankcase. The flow direction of the crankcase ventilation line is considered to lead away from the crankcase and thus leading to the intake air line. Within the scope of this disclosure, it is defined that inclusive is synonymous with downstream. Upstream is therefore synonymous with leading away.It is provided that the integrity of the crankcase ventilation line can be checked. In other words, a state is detected. This state may be proper, i.e. integer, or improper, i.e. non-integer. These include, in particular, the proper functioning of the backflow prevention devices, the presence of holes and / or cracks in the crankcase ventilation line, and the proper connection of the crankcase ventilation line to the oil separator and / or the intake air line and / or to the backflow prevention devices and / or the pressure control unit and / or the crankcase ventilation line branch. A proper state of the crankcase ventilation system is understood within the scope of this disclosure to mean that all the lines of the crankcase ventilation system are correctly connected and sealed at their respective connection points. This means that there are no leaks at the connection points, in lines themselves or at the connection points of line and connection piece (not shown). Furthermore, it is understood that all backflow prevention devices function correctly. This means that the backflow prevention devices do not remain completely or partially in one position. In other words, the backflow prevention devices are not jammed.Improper refers to failing proper in this disclosure. In other words, improper is any state in which proper state is not present or is determined.It has been found to be advantageous that a sensor unit in the crankcase ventilation line generates a signal which is compared with a comparison value. The signal itself reflects a value. This value denotes a characteristic of a current. From the comparison of the value and the comparison value, the state of the crankcase ventilation line and / or of the crankcase ventilation line is closed. In other words, damage to the integrity of the crankcase ventilation line and / or the crankcase ventilation line is determined.The arrangement of the sensor unit in the crankcase ventilation line is advantageous because the contamination of the sensor unit here is significantly reduced compared to an arrangement in the crankcase ventilation line and the current circulating around the sensor unit can be less corrosive than in the case of an arrangement of the sensor unit in the crankcase ventilation line. The arrangement of the sensor unit in the crankcase ventilation line is particularly advantageous since the entire crankcase ventilation line can be checked for its integrity by means of only one sensor. It is understood that also included here are the backflow prevention devices arranged in the crankcase ventilation line and the pressure regulating unit. By arranging the sensor unit in the crankcase ventilation line, a diagnosis of the crankcase ventilation line for its integrity can be carried out.An embodiment of the comparison of the value of the signal of the sensor unit with the comparison value can be a difference of the two values. Within the scope of this disclosure, it is established that the value of the signal of the sensor unit is denoted by w s, the comparison value is denoted by w v and the determined difference is denoted by D s-v. It is also established that, in one embodiment, the difference D s-v is determined by means of subtraction with the measured value w s as minuend and the comparison value w v subtrahend and is designated by the difference D s-v when this method is used. In other words, D s-v= w s- w v.It is further determined that an allowable deviation of the difference D s-v is referred to as D z. The allowable difference D z is determined depending on the operating point. In one embodiment, the permissible difference D z is formed as a function of the operating point relative to the comparison value of the operating point. In another embodiment, the permissible difference D z is predefined in the form of an absolute value for the respective operating point. A catalog can be used to determine the dependence of the operating point. The catalog may consist of a single value. A function can be used to determine the dependence of the operating point. The permissible deviation D z can likewise be predefined fixedly, in each case relatively and absolutely.It is understood that the comparison value w v a predefinable value, or is measured by a measuring device (not shown). In one embodiment, the comparison value can be dependent on the operating point. In another embodiment, the predefined comparison value cannot be dependent on the operating point. This can have an advantageous effect, since the availability of comparison values can be increased as a result if the predefined or measured value is not available.A total of six figures are shown. This shows, in a partially highly schematic manner:FIG. 1 shows a first embodiment, not claimed, of an arrangement of an internal combustion engine with a connection point of the crankcase ventilation line to the intake air line,FIG. 2 shows a second non-claim embodiment of an internal combustion engine,FIG. 3 shows a third embodiment of an internal combustion engine, not claimed,FIG. 4 shows a fourth embodiment of an internal combustion engine,FIG. 5 shows a fifth embodiment of an internal combustion engine,FIG. 6 shows an exemplary sequence of the method.The internal combustion engine is shown in highly schematic form by the crankcase 17 and the combustion chamber 31. The structure of an internal combustion engine with a reciprocating piston engine is clear to the person skilled in the art.FIG. 1 shows, in an embodiment which is not claimed, an arrangement with a connection point of the crankcase ventilation line 3 to the intake air line 2, an internal combustion engine 1 without a turbocharger 5 being shown. It is provided here that the connection of the crankcase ventilation line 4 to the intake air line 2 is arranged between the throttle valve 6 and the connection of the crankcase ventilation line 3 at the first connection point 13 to the intake air line 2. In the intake air passage 2, an intake air passage branch 20 is disposed downstream of the throttle 6. Furthermore, a charge air cooler 19 can be arranged between throttle valve 6 and intake air line branch 20. It is provided that the crankcase ventilation line 3 is connected to the intake air line 2 at the crankcase ventilation line connection 28 between the air filter 8 and the first connection point 13. The crankcase ventilation line 3 is furthermore connected to the crankcase 17. In particular, it is provided that the first connection point 13 of the crankcase ventilation line 3 and the crankcase ventilation line connection 28 are spaced apart. Furthermore, it is provided that an at least one first backflow prevention device 26 is arranged in the crankcase ventilation line 3 and / or at least one first throughflow influencing device 7 is arranged upstream of the sensor unit 18. This makes it possible to diagnose the damage to the integrity of the crankcase ventilation line 3, in particular to the first backflow prevention device 26 and / or to the first flow limiting device 7 in suction operation.FIG. 2 shows an arrangement corresponding and further developed to FIG. 1 in an embodiment which is not claimed. Here, in addition to FIG. 1, a turbocharger 5 is arranged between the first connection point 28 and the throttle valve 6. The first port 28 is disposed in local proximity to the inlet side of the turbocharger 5. The first connection point 26 can also be connected to the housing of the turbocharger 5, with the result that the connection to the intake air line 2 takes place through and / or in the housing of the turbocharger 5. As a result, the internal combustion engine 1 can be operated in a boosted and a non-boosted state. In both states, a diagnosis of a proper or improper state of the crankcase ventilation line 4 and of the crankcase ventilation line 3 can thus be concluded.FIG. 3 shows, in an embodiment which is not claimed, an arrangement which corresponds and is further developed in FIG. 2. Here, in addition to FIG. 2, the crankcase ventilation line 4 with the first connection point 13 and a second connection point 15, i.e. a total of two connection points, to the intake air line 2 is formed. In this case, the crankcase ventilation line 4 consists of the part 24 and of the first line 29 and of the second line 30, i.e. the crankcase ventilation line 4 branches at the crankcase ventilation line branch 21 into a first line 29 and into a second line 30, It is provided in this case that at least one turbocharger 5 and at least one throttle valve 6 are arranged between the connection points 13, 15 of the crankcase ventilation line 4 branched into the first line 29 and the second line 30 to the intake air line 2. Furthermore, it is provided that third connection point 15 of crankcase ventilation line 4 to intake air line 2 is situated downstream of throttle valve 6 and upstream of intake air line branch 20. Furthermore, between the crankcase ventilation line branch 21 and the connection points of the crankcase ventilation line 13, 15 to the intake air line, at least one backflow prevention device 9, 11 per line is arranged in the first line 29 and in the second line 30, respectively. This makes it possible to diagnose the damage to the integrity of the backflow prevention devices 9, 11 both in the suction mode and in the supercharged mode. In this case, differentiated diagnosis of the individual backflow prevention devices 9, 11 is possible. Furthermore, a diagnosis of the connection points 13, 15 of the crankcase ventilation line 4 is possible.FIG. 4 shows an arrangement corresponding and further developed to FIG. 3. Here, in addition to FIG. 3, a pressure regulating unit 22 is arranged between crankcase ventilation line branch 21 and crankcase 17. Here, the crankcase ventilation line 4 consists of the part 24 and of the first line 29 and of the second line 30. an oil separator 25 is regularly arranged between the pressure regulating unit 22 and the crankcase 17. By means of the pressure regulating unit 22, a pressure in the crankcase 17 and in the crankcase ventilation line 4 can be adjusted in a targeted manner. Thus, a reliable diagnosis of the backflow prevention devices 9, 11 arranged in the first line 29 and in the second line 30 can be carried out in the charged and in the non-charged state. In other words, a proper or improper state may be detected. The pressure regulating unit 22 makes it possible for respective associated negative pressures in the crankcase 17 and thus in the crankcase ventilation line 4 to be associated with different operating states, with the result that differentiated diagnosis of the crankcase ventilation line 4 and of the backflow prevention devices 9, 11 arranged therein and of the first line 29 and of the second line 30 to the intake air line 2 is made possible. The integrity of the crankcase ventilation line 4 can thus be checked.FIG. 5 shows an arrangement corresponding to FIG. 4 and further developed. Here, the crankcase ventilation line 4 consists of the section 24, the first line 29, the second line 30, a third line 37, a fourth line 38, a fifth line 39 and a sixth line 40.The first connection point 70 is formed in this arrangement from a first connection point 14 and a third connection point 34. Functionally, it corresponds to the first connection point 13 from FIG. 3 or FIG. 4, for example.The second connection point 80 is formed in this arrangement from a second connection point 16 and a fourth connection point 35. Functionally, the second connection point 80 corresponds to the second connection point 15 from FIG. 3 or FIG. 4, for example.In the arrangement shown in FIG. 5, the first line 29 is divided at a branch 36 into a third line 37 and a fourth line 38. In the third pipe 37, a third backflow prevention device 10 is disposed. The third line 37 is connected to the intake air line 2 between the turbocharger 5 and the crankcase ventilation line connection 28 at the first connection point 14. In the fourth conduit 38, a sixth backflow prevention device 32 is arranged. The fourth line 38 is connected to the intake air line 2 between the turbocharger 5 and the crankcase ventilation line connection 28 at the third connection point 34.In the arrangement shown in FIG. 5, the second line 30 is divided at a branch 41 into a fifth line 39 and a sixth line 40. In the fifth pipe 39, a seventh backflow prevention device 39 is disposed. The fifth line 39 is connected to the viewing air line 2 between the throttle valve 6 and the intake air line branch 20 at the fourth connection point 35. In the sixth pipe 40, a fifth backflow prevention device 12 is disposed. The sixth passage 40 is connected to the intake air passage 2 between the throttle valve 6 and the intake air passage branch 20 at the second connection point 16. The backflow prevention devices 10, 12, 32, 33 are spaced apart from the respective connection points 14, 16, 34, 35.Furthermore, it is provided that the pressure regulating unit 22 comprises an adjusting function and that the pressure regulating unit 22 is connected to a computer unit (not shown) for presetting a pressure to be set by the computer unit. This allows the specification of a pressure, so that in different operating states, different subassemblies of the crankcase ventilation system 23, in other words the crankcase ventilation line 3 and the crankcase ventilation line 4 and the devices comprising them in each case, can be diagnosed as having an damage to the integrity by the specification of different pressures. In one embodiment, the greatest possible predeterminable negative pressure in the crankcase 17 and thus also in the crankcase ventilation line 4 is in a predeterminable range of preferably 5 hPa to 300 hPa, particularly preferably 15 hPa to 200 hPa and even more preferably 30 hPa to 150 hPa below the respective atmospheric pressure.It is advantageous here that the pressure which can be predetermined by the computer unit is dependent on an operating point. This is particularly favorable since this can be used to specifically determine associated pressure specifications, for example, via a stored catalog. In another embodiment, instead of using a catalog, the predefinable pressure can be determined on the basis of the operating point by means of a calculation model with the computer unit.FIG. 6 shows a possible sequence of the method for diagnosing the integrity of the crankcase ventilation system 23.detecting an operating state in step S 10,detecting a signal of the sensor unit 18 in step S20,determining a measured value w s on the basis of the signal of the sensor unit 18 in step S30,determining a comparison value w v in step S40,determining a difference D s-v between the measured value w s and the comparison value w v in step S50,determining a permissible deviation D z in step S60,comparing the difference D s-v with the allowable deviation D z in step S70,determining a state based on the comparison in step S80,triggering at least one measure corresponding to the ascertained state in step S90.These steps S 10 to S 90 can also be carried out by the person skilled in the art in a sequence of steps differing from the previous description.It is provided that the procedure of the diagnosis is carried out directly after a release condition has been present. A release condition can be, for example, a predeterminable time after engine start and / or a traveled plug and / or an exceeded engine speed.In another embodiment, it is provided that the detection of an operating state and the detection of a signal of the sensor unit 18 take place in the vicinity of time. As a result, a measure can be triggered already during the operation of the vehicle, preferably in direct temporal proximity for detecting the operating state. A time proximity is understood here to mean a time period of at most one minute, preferably at most 15 seconds, further preferably at most 5 seconds. As a result, the improper state can be detected as quickly as possible. As a result, the computational load present for the computer unit can be equalized.In another embodiment, it is provided that both the comparison value w v associated with the operating state and the detected signal of the sensor unit 18 associated with the operating state are provided with a marking corresponding to a temporal profile. Both the comparison value and the signal of the sensor unit are stored in a memory (not shown). At a time interval, a diagnosis is carried out by comparing the measured value of the signal of the sensor unit w s stored in the memory and the comparison value w v stored in the memory. The method furthermore provides that only those captured measured values of the signal of the sensor unit w s and comparison values w v are used for the comparison, the temporal identifier of which matches or lies within a predefinable temporal interval. As a result of the diagnosis, a measure is triggered in the presence of the corresponding result. The diagnosis spaced apart in time allows the computing power of the computer unit to be designed to be lower. Likewise, the diagnosis can be carried out at a point in time at which the power of the computer unit is available in a favorable manner, so that no other processes, which may be relevant to safety, are impeded and / or slowed down. Likewise, at a later point in time, a (new) evaluation of the collected data can be carried out. Statistical evaluations can also be carried out in this case. These statistical evaluations can be carried out in the vehicle and / or can be transmitted wirelessly and / or by wire to an external evaluation unit. The results of the statistical evaluations can be used in the diagnosis and the specific assignment of a defective component. In a further embodiment, the established state is stored on the basis of the comparison S 80 in a memory (not shown), preferably in conjunction with a time identification. This is advantageous since this facilitates a fault finding. This also enables the transmission of the collected detected conditions based on the comparison S80.Within the scope of this disclosure, a measure is, for example, an entry into a fault memory (not shown) of the vehicle, an increase in a fault memory counter (not shown), an output in a form (not shown) which is preferably perceptible by eyes and / or ears for the driver, an output for a person viewing the vehicle from the outside in a form (not shown) which is preferably perceptible by eyes and / or ears, a wireless relay to another vehicle, which is preferably located in the direct vicinity, and / or an infrastructure device (not shown), a wireless relay to a (computer-aided) control center or device for collecting data (not shown), a limitation of the operating states of the vehicle, the limitation of the maximum torque to be supplied by the internal combustion engine, and, limiting the maximum number of revolutions of the engine to be supplied by the internal combustion engine, limiting the remaining operating time, limiting the remaining route, and omitting a restart. Combinations of the aforementioned measures are possible.In a proper state, the vehicle may be operated in an uncharged state. Examples of arrangements that allow for an uncharged state are listed in FIGS. 1, 2, 3, 4 and 5.In a proper state, the vehicle may be operated in a boosted state. Examples of arrangements that allow a charged state are listed in FIGS. 2, 3, 4 and 5.In an unloaded proper state, the backflow prevention devices 11, 12, 35 are opened and the backflow prevention devices 9, 10, 32 are closed. In a charged proper state, the backflow prevention devices 9, 10, 32 are opened and the backflow prevention devices 11, 12, 35 are closed.The integrity of the crankcase ventilation system 23 is diagnosed by comparing the difference D S-V with the permissible deviation D Z. If the comparison is expected and correct on the basis of the determination of a state on the basis of the comparison in step S 80, then there is no damage to the crankcase ventilation system 23. This applies to the non-charged state and to the charged state.If an improper state exists, a pressure is established in the intake air line 2 and thus in the crankcase ventilation line 3, which does not correspond to the expectation. This changed pressure is detected by the sensor unit 18. A difference D s-v is therefore determined which results in an incorrect state when compared with the permissible difference D z in step S 80.An improper state of the backflow prevention devices 9, 10, 11, 12, 32, 35 may be considered a clamping or jammed backflow prevention device 9, 10, 11, 12, 32, 35. The backflow preventer 9, 10, 11, 12, 32, 35 then remains in an improper state.In an unloaded state with the first backflow prevention device 26 in a proper state, therefore, the improper state of at least one backflow prevention device 11, 12, 35 can be diagnosed in a closed state. In other words, at least one backflow prevention device 11, 12, 35 does not remain properly in a closed state.In an unloaded operation with the first backflow prevention device 26 in the proper state, therefore, the improper state of at least one backflow prevention device 9, 10, 32 can be diagnosed in an open state. In other words, at least one backflow prevention device 9, 10, 32 does not remain properly in an open state. In a charged state with the first backflow prevention device 26 in a proper state, therefore, the improper state of at least one backflow prevention device 9, 10, 32 can be diagnosed in a closed state. In other words, at least one backflow prevention device 9, 10, 32 does not remain properly in a closed state.In a charged state with the first backflow prevention device 26 in a proper state, therefore, the improper state of at least one backflow prevention device 11, 12, 35 in an open state can be detected. In other words, at least one backflow prevention device 11, 12, 35 does not remain in an open state properly. In an uncharged or a charged state with the first backflow prevention device 26 in the proper state, a leakage of the crankcase ventilation line 4 and / or an improper connection of at least one connection point 13, 15, 70, 80 can be diagnosed. In this case, it applies that a small leakage has a lower effect than a large leakage on the measured value of the signal of the sensor unit w s. Thus, the difference D s-v will also change accordingly. The same applies to the connection points 13, 15, 70, 80 of the crankcase ventilation line 4 to the intake air line 2. the more connection points 13, 15, 70, 80 are not proper, the greater the effect on the measured value of the signal of the sensor unit w s and thus on the difference O s-v.List of reference characters1 2 Intake air line 3 Crankcase ventilation line 4 Crankcase ventilation line 5 Turbocharger 6 Throttle valve 7 First flow influencing device 8 Air filter 9 Second backflow prevention device 10 Third backflow prevention device 11 Fourth backflow prevention device 12 Fifth backflow prevention device 13 First connection point 14 First connection point 15 Second connection point 16 Second connection point 17 Crankcase 18 Sensor unit 19 Charge air cooler 20 Intake air line branch 21 Crankcase ventilation line branch 22 Pressure control unit 23 Crankcase ventilation system 24 Section 25 Oil separator 26 First backflow prevention device 27 Absent 28 Crankcase ventilation line connection 29 First line 30 Second line 31 Combustion chamber 32 Sixth backflow prevention device 33 Seventh backflow prevention device 34 Third connection point 35 Fourth connection point 36 First branch 37 Third line 38 fourth line 39 fifth line 40 sixth line 41 second branch 70 first connection point 80 second connection point w s measured value of the signal of sensor unit w v comparison value D s-v difference D z permissible deviation S 10 to S 90 steps 10 to 90

Claims

Internal combustion engine having a crankcase ventilation system (23), comprising a crankcase (17), an intake air line (2), wherein the intake air line (2) comprises a throttle valve (6) and an air filter (8), and having a crankcase ventilation line (4) for ventilating the crankcase (17) and a crankcase ventilation line (3) for scavenging the crankcase (17), wherein the crankcase ventilation line (4) is arranged at a first connection point (13, 70) downstream of the air filter (8) to the intake air line (2), wherein a sensor unit (18) is arranged in the crankcase ventilation line (3) downstream of a first throughflow influencing device (7) and upstream of a first backflow prevention device (26), wherein the first connection point (13, 70) is arranged downstream at a distance from a crankcase ventilation line connection (28) to the intake air line (2), such that a malfunction of the crankcase ventilation system (23) can be detected by the sensor unit (18), wherein a turbocharger (5) is arranged downstream of the first connection point (13, 70) and upstream of the throttle valve (6), wherein the turbocharger (5) and the throttle valve (6) are arranged between the first connection point (13, 70) and a second connection point (15, 80), wherein the second connection point (15, 80) is arranged on the intake air line (2), characterized in that the crankcase ventilation line (4) comprises a crankcase ventilation line branch (21) and a pressure regulating unit (22), wherein the pressure regulating unit (22) is arranged upstream of the crankcase ventilation line branch (21).Internal combustion engine according to Claim 1, wherein a respective backflow prevention device (9, 10, 11, 12, 32, 33) is arranged upstream of the respective connection points (13, 15, 70, 80) of the crankcase ventilation line (4) to the intake line (2).Internal combustion engine according to Claim 1 or 2, wherein a volume flow from the crankcase (17) into the intake line (2) is set by the pressure regulating unit (22) such that a predeterminable negative pressure in the crankcase (17) is achieved in the best possible manner.Internal combustion engine according to one of the preceding claims, wherein the pressure regulating unit (22) comprises an active actuating function and that the pressure regulating unit (22) is connected to a computer unit for presetting a pressure to be set.Internal combustion engine according to Claim 4, wherein the pressure which can be specified by the computer unit is operating point-dependent.Method for operating an internal combustion engine according to one of the preceding claims 1 to 5, comprising the following steps, - detecting an operating state, - detecting a signal of the sensor unit (18), - determining a measured value w s on the basis of the signal of the sensor unit (18), - determining a comparison value w v, - determining a difference D s-v between the measured value w s and the comparison value w v, - determining a permissible deviation D z, - comparing the difference D s-v with the permissible deviation D z, - determining a state on the basis of the comparison, - triggering at least one measure corresponding to the determined state.Motor vehicle having an internal combustion engine according to one of Claims 1 to 5 and / or operated according to the method in Claim 6.

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