DE102018217630A1 - Tank vent valve unit - Google Patents

Abstract

The invention relates to a tank ventilation valve unit (1) for use in a tank ventilation system (100) of an internal combustion engine, in particular for use in a flow path of a tank ventilation line (7). The tank ventilation valve unit is arranged downstream of a pressure increasing unit (9) and upstream of an air intake path (10) of the internal combustion engine and comprises a tank ventilation valve (5) and a bypass flow path (4). The tank ventilation valve (5) can be connected on the input side to a tank ventilation line (7) in a fluid-conducting manner and on the output side to a connection point of the air intake path (10). In a closed state, the tank ventilation valve (5) prevents the passage of a flushing medium through the tank ventilation valve (5) and in an open state, the tank ventilation valve (5) allows the passage of a flushing medium through the tank ventilation valve (5). A bypass flow path (4), a path entrance of the bypass flow path (4) being fluidly connectable to the tank ventilation line (7). A first path end of the bypass flow path (4) is designed such that a sealing connection can be established between the first path end and an outside of the air intake path (10), the sealing connection not having any fluid-conducting connection to the inside of the air suction path (10). According to the invention, a method for diagnosing a tank ventilation system, in particular a connection of a tank ventilation valve unit to an air intake path of an internal combustion engine, is also provided.

Description

The invention relates to a tank ventilation valve unit for use in a tank ventilation system of an internal combustion engine. Furthermore, the invention relates to a method for diagnosing a tank ventilation system and a motor vehicle with a tank ventilation valve unit.

When operating an internal combustion engine, a large part of the pollutants emitted is due to combustion-related exhaust gas. There are also other sources responsible for pollutant emissions. These sources can include, for example, vapors from a fuel tank of the internal combustion engine.

Fuels such as super gasoline, which can be stored in the fuel tank, have a number of volatile hydrocarbons. These include, for example, methane, butane and propane. In order to protect the fuel tank from mechanical damage when there is a change in the volume of the fuel and to allow pressure equalization between the fuel tank and the circulating air, the fuel tank can be coupled to the circulating air via a line. The readily volatile hydrocarbons can be released from the fuel in particular at elevated outside temperatures, for example due to sunshine, or also by shaking the fuel tank during a journey, and can leave the fuel tank as gaseous components via the line.

Today's internal combustion engines have tank ventilation systems in which fuel evaporated in the tank is stored, for example, in an activated carbon filter which is connected to the intake manifold of the internal combustion engine via a lockable tank ventilation valve. When the tank ventilation valve is open, air is drawn in via a connection of the activated carbon filter to the surroundings, which entrains the temporarily stored fuel and leads to combustion. The amount of gas drawn in is controlled via the tank ventilation valve in such a way that, on the one hand, the activated carbon filter is sufficiently flushed with air and, on the other hand, there are no intolerably large disturbances in the fuel-air ratio of the mixture supplied to the internal combustion engine.

For the purpose of compliance with various country-specific legal regulations, it is necessary to ensure the functionality of a tank ventilation system, i.e. that, among other things, a defective tank ventilation valve installed in a tank ventilation system or leaking or blocked pipes must be recognized as defective by suitable diagnoses.

It is known from the prior art that the functionality of that area of the tank ventilation path, which is located downstream between the pressure booster unit and the point of introduction into the air intake path of the internal combustion engine, is checked with the aid of a tank leakage diagnosis component, such as a shut-off valve and one Pressure detection unit, can be carried out, wherein a pressure increasing unit is designed in such a way that there is a continuous line connection from the air filter upstream to the activated carbon filter up to the connection to the tank ventilation valve unit. In order to be able to evaluate the functionality of the entire tank ventilation system, the tank ventilation valve and the connection point to the air intake path of the internal combustion engine must be diagnosed.

It proves to be disadvantageous that there is almost ambient pressure at the connection point of the tank ventilation valve after the air filter, so that even with high mass flows in the area after the air filter there is only a very small pressure drop, which means that only at certain operating points of the internal combustion engine (very high engine loads ) a meaningful differential pressure to the ambient pressure level can be measured on the pressure detection unit. Accordingly, a distinction between a tank ventilation valve that is not correctly connected to the inlet point of the air intake path and a correctly connected tank ventilation valve is not guaranteed with the necessary selectivity.

Up to now, diagnosis of the above-mentioned connection point has only been possible in very limited operating points of the internal combustion engine with high engine loads with high air mass flows and only by actively controlling the tank ventilation valve, with the sensor system only being able to evaluate the differential pressure to the environment that occurs at high engine loads can be when the vacuum generating point is downstream of the connection point in the air intake path of the internal combustion engine.

The present invention has for its object to at least partially overcome the problems known from the prior art and to provide an improved tank ventilation valve unit for use in a tank ventilation system of an internal combustion engine and an improved method for diagnosing a tank ventilation system which is very reliable in one with simple means Tank ventilation system built-in defective tank ventilation valve or leaking or blocked pipes through suitable diagnostics can detect, the method should be as simple as possible, efficient and inexpensive.

The invention solves this problem by means of a tank ventilation valve unit for use in a tank ventilation system of an internal combustion engine, by means of a method for diagnosing a tank ventilation system and by means of a motor vehicle with an internal combustion engine with the features of the independent claims.

Advantageous further developments, additional features and / or advantages of the invention result from the dependent claims and the following description of the invention.

According to a first aspect of the invention, a tank ventilation valve unit for use in a tank ventilation system of an internal combustion engine, in particular for use in a flow path of a tank ventilation line, is disclosed. The tank ventilation valve unit is arranged downstream of a pressure increasing unit and upstream of an air intake path of the internal combustion engine and comprises a tank ventilation valve and a bypass flow path. The tank ventilation valve can be connected on the inlet side to a tank ventilation line in a fluid-conducting manner and on the outlet side to a connection point of the air intake path. In a controlled, in particular in a de-energized, closed state, the tank ventilation valve prevents the passage of a flushing medium through the tank ventilation valve and in an open state, the tank ventilation valve allows the passage of a flushing medium through the tank ventilation valve. A first path end of the bypass flow path is designed such that a sealing connection can be established between the first path end and an outside of the air suction path, the sealing connection not having any fluid-conducting connection to the inside of the air suction path.

In this way, a tank ventilation valve that is not correctly connected to the air intake path of the internal combustion engine can be diagnosed robustly and with the necessary selectivity at all operating points of the internal combustion engine.

Furthermore, an additional pressure sensor system in the air intake path of the internal combustion engine at the connection point of the tank ventilation line can be omitted.

The direct connection of the tank ventilation valve to the air intake path of the internal combustion engine means that a propagation model for modeling the mass flow from the tank ventilation valve to the connection point in the air intake path can be omitted, which increases the quality of the modeling of the propagation of the mass flow through the tank ventilation valve up to the inlet or exhaust tract of the internal combustion engine.

The cohesively sealing connection is advantageously designed such that an incorrect connection of the connection of the tank ventilation valve to the connection point results in the opening of the connection, which is connected to the air intake pipe in particular via a seal (e.g. an O-ring seal).

In a particularly preferred embodiment, the bypass flow path is rigid in relation to the tank ventilation valve.

In a further advantageous embodiment, a second path end of the bypass flow path can be connected in a fluid-conducting manner to the inlet side of the tank ventilation valve.

According to the invention, it is provided that the cohesively sealing connection is made by means of a flange arranged on the outside of the air intake path, the bypass flow path being connected in the interior of the flange by means of at least one sealing ring in such a way that flushing medium flowing into the bypass flow path does not come out of the bypass -Current path can leak.

In a preferred embodiment, a check valve which is attached to the tank ventilation valve on the input side or on the output side can ensure that the flushing medium only flows from the input side to the output side of the TEV.

The cohesively sealing connection advantageously has at least one single seal, preferably a double seal.

In a particularly advantageous embodiment, the tank ventilation valve unit is controlled electrically via a map value from the control of the internal combustion engine. Alternatively, the tank ventilation valve unit can be controlled on the basis of the mass flow of the flushing medium supplied to the internal combustion engine or the level of at least one ambient pressure.

In a particularly advantageous embodiment, a pressure increasing unit is provided in the tank ventilation line path upstream of the tank ventilation valve unit.

S1

Öffnen eines Tankentlüftungsventils der Tankentlüftungsventileinheit für einen ersten Zeitraum und Erfassen eines ersten Verlaufs zumindest eines Betriebsparameters;

S2

Schließen des Tankentlüftungsventils der Tankentlüftungsventileinheit für einen zweiten Zeitraum und Erfassen eines zweiten Verlaufs des einen Betriebsparameters; und

S3

Bestimmen eines Fehlerzustandes eines Anschlusses der Tankentlüftungsventileinheit an den Ansaugtrakt und/oder der Tankentlüftungsleitung zumindest teilweise anhand des ersten und des zweiten Verlaufs des Betriebsparameters.

According to a further aspect of the invention, a method for diagnosing a tank ventilation system, in particular a connection of a tank ventilation valve unit to an air intake path of an internal combustion engine, forms another Subject of the invention. The tank ventilation system includes a tank ventilation line. This is set up to conduct a flow of a flushing medium from a fuel tank to the intake tract, wherein at least one pressure increase unit is arranged downstream of the fuel tank and at least one pressure detection unit is arranged in a flow path of the tank ventilation line downstream or upstream of the pressure increase unit. The tank ventilation line is connected in a fluid-conducting manner downstream of the pressure detection unit to an input side of a tank ventilation valve unit according to the invention. The process comprises the following steps:

S1

Opening a tank ventilation valve of the tank ventilation valve unit for a first period of time and detecting a first course of at least one operating parameter;

S2

Closing the tank ventilation valve of the tank ventilation valve unit for a second period of time and detecting a second course of the one operating parameter; and

S3

Determining an error state of a connection of the tank ventilation valve unit to the intake tract and / or the tank ventilation line at least in part on the basis of the first and the second course of the operating parameter.

The method according to the invention for flushing pipe diagnosis has the advantage over the prior art that it can be carried out without an active intervention in the tank ventilation function, thereby ensuring an increase in the tank ventilation flushing rate during the driving cycle.

The operating parameter is advantageously a differential pressure to the surroundings of the pressure increasing unit.

In a preferred embodiment, the operating parameter is an electrical power consumption of the pressure increasing unit.

It is advantageous according to the invention that the fault condition of the connection of the tank ventilation unit is diagnosed on the basis of the observation that the first course of the differential pressure to the surroundings of the pressure increasing unit is qualitatively the same as the second course of the differential pressure to the surroundings pressure increasing unit.

The tank ventilation valve unit according to the invention can be provided in a motor vehicle. Accordingly, a motor vehicle with an internal combustion engine, which is equipped with a tank ventilation valve unit, also forms a further subject of the invention, the tank ventilation valve unit being used in a tank ventilation system described above.

Further features, possible applications and advantages of the invention result from the following description of an embodiment of the invention. It should be noted that the features shown are only descriptive and can also be used in combination with features of other developments described above and are not intended to limit the invention in any way.

• 1 zeigt beispielhaft eine schematische Darstellung der Tankentlüftung;
• 2 zeigt eine schematische Darstellung eines erfindungsgemäßen Tanktentlüftungssystem mit Bypass in einer ersten Ausführungsform der vorliegenden Erfindung;
• 3 zeigt eine schematische Darstellung eines erfindungsgemäßen Tanktentlüftungssystem mit Bypass in einer zweiten Ausführungsform der vorliegenden Erfindung;
• 4 zeigt beispielhaft einen Diagnoseablauf in zwei Abschnitten bei einem erfindungsgemäßen Verfahren die zeitlichen Verläufe verschiedener Werte und Stellgrößen bei einem nominalen bzw. fehlerfreien Tankentlüftungssystem;
• 5 zeigt beispielhaft einen Diagnoseablauf in zwei Abschnitten bei einem erfindungsgemäßen Verfahren die zeitlichen Verläufe verschiedener Werte und Stellgrößen bei einem blockierten Tankentlüftungssystem; und
• 6 zeigt beispielhaft einen Diagnoseablauf in zwei Abschnitten bei einem erfindungsgemäßen Verfahren die zeitlichen Verläufe verschiedener Werte und Stellgrößen bei einem Druckverlust bzw. einer fehlerhaften offenen Leitungsverbindung im Tankentlüftungssystem.

The invention will now be described in more detail with reference to the accompanying figures. The drawings are schematic and show:

• 1 shows an example of a schematic representation of the tank ventilation;
• 2nd shows a schematic representation of a tank ventilation system according to the invention with bypass in a first embodiment of the present invention;
• 3rd shows a schematic representation of a tank ventilation system according to the invention with bypass in a second embodiment of the present invention;
• 4th shows an example of a diagnostic process in two sections in a method according to the invention, the time profiles of different values and manipulated variables in a nominal or error-free tank ventilation system;
• 5 shows an example of a diagnostic process in two sections in a method according to the invention, the time profiles of different values and manipulated variables in a blocked tank ventilation system; and
• 6 shows an example of a diagnostic sequence in two sections in a method according to the invention, the time profiles of different values and manipulated variables in the event of a pressure loss or a faulty open line connection in the tank ventilation system.

1 provides an example of a tank ventilation system 100 an internal combustion engine, not shown, with a tank ventilation valve unit 1 The tank ventilation system 100 includes a tank container 11 to hold fuel 20th that has a tank connection line 14 with a sorption filter 8th is fluidly connected. The sorption filter 8th can be designed as an activated carbon filter, which temporarily store volatile components of evaporating fuel through adsorption and desorption can. The sorption filter 8th is also with the internal combustion engine upstream air intake path 10th via a tank ventilation line 7 and flushing medium fluidly connected. The air intake path 10th guides the internal combustion engine through an air filter 17th filtered ambient air. Via the tank connection line 14 can therefore volatile components of the fuel 20th , like hydrocarbons, from the tank 11 into the sorption filter 8th directed, stored and from there via a clocked or linearly controlled tank ventilation valve unit 1 and the tank vent line 7 an air intake path 10th of the internal combustion engine are metered for combustion.

To implement a pressure gradient and a related mass flow between the ambient pressure and the point of introduction into the air intake path 10th is a pressure booster 9 , for example a rinsing pump is provided. Inside the tank ventilation line 7 are both upstream and downstream of the booster unit 9 at least one, in the illustrated embodiment two pressure detection units 24th , 25th arranged. The pressure booster unit 9 is designed in such a way that a continuous line connection from the air filter 15 upstream to the sorption filter 8th up to the connection to the tank ventilation valve unit 1 given is. By executing a tank leakage functionality with the aid of a tank leakage diagnosis component 16 as well as the pressure detection units 24th , 25th can affect the functionality of the tank ventilation system 100 including the fuel tank 11 and the tank ventilation line 7 up to the connection to the tank ventilation valve unit 1 be determined.

The tank ventilation line 7 has a check valve 22 on, which serves a unidirectional mass flow to the air intake path 10th to ensure the internal combustion engine.

For regeneration of the adsorption filter 8th becomes the tank vent valve 1 opened so that due to that in the air intake path 10th prevailing negative pressure air of the atmosphere through the adsorption filter 8th is sucked, which in the adsorption filter 8th accumulated hydrocarbons in the tank ventilation line 7 sucked and fed to the internal combustion engine.

The tank vent valve unit 1 , which can be designed as a switching or linear valve, can be controlled by a motor control using a pulse width modulated (PWM) signal and regulates the flushing medium from the sorption filter 8th to the discharge points in the air intake path 10th of the internal combustion engine. According to the invention, it is provided that the engine control system determines, among other things, a target value for the mass flow for the current operating state and a current intake manifold pressure with the aid of a pressure sensor (not shown) in the intake tract. From the resulting pressure drop between the pressure increasing unit 9 and the pressure at the point of introduction in the air intake path 10th of the internal combustion engine becomes the pulse-width modulated (PWM) signal for controlling the tank ventilation valve from the specified mass flow 1 determined and the amount of fuel to be injected for the current operating state of the internal combustion engine is calculated.

Then for the above-mentioned point of introduction of the tank ventilation into the air intake path 10th of the internal combustion engine the delay time due to the opening of the tank ventilation valve 1 the mass flow supplied to the combustion is calculated and a fuel correction is made on the basis of the two pressure detection units 12th learned (modeled) and calculated by means of lambda controller deviation hydrocarbon concentration of the mass flow. Accordingly, the internal combustion engine does not have one 1 Lambda controller shown.

In 2nd and 3rd are exemplary two different embodiments of a tank ventilation valve unit according to the invention 1 shown. The tank vent valve unit 1 includes the tank vent valve 5 and an associated electrical connection 2nd . According to the invention is a bypass flow path 4th provided, for example, as in 2nd shown, starting from the tank ventilation line 7 branches and via a separate line on the tank ventilation valve 5 over to a path entrance 41 to a first deposit 42 , or, as in 3rd shown, in one, the entire tank vent valve 5 enclosing tank ventilation line 7 leads.

In both embodiments, the tank ventilation line leads 7 via the tank ventilation valve 5 to a junction 12th to the air intake path 10th .

By integrating bypass flow path 4th into the tank ventilation valve unit 1 this is when the tank ventilation valve is correctly connected 5 with the air intake path 10th of the internal combustion engine, sealed pressure-tight. The bypass flow path 4th is cohesive and therefore without plug or screw connections with the tank ventilation valve 5 connected.

Both the junction 12th as well as the first end of the path 42 of the bypass flow path 4th is about a seal 6 , preferably also via a double seal with the air intake path 10th or with the tank ventilation valve 5 connected.

Here is the tank ventilation valve unit 1 structurally designed so that if the tank ventilation valve is incorrectly connected 5 at the junction 12th to the air intake path 10th the internal combustion engine automatically a further bypass flow path 4th upstream or downstream of the tank ventilation valve 5 opens in the direction of ambient pressure.

An example is in 2nd and 3rd a check valve at different positions 3rd in the tank ventilation valve unit 1 integrated.

Because of this constructive characteristic of the tank ventilation valve unit 1 can be an incorrectly connected tank vent valve 5 with the air intake path 10th of the internal combustion engine can be diagnosed with sufficient selectivity by the method according to the invention without influencing the actual tank ventilation strategy.

The in 4th The course of the respective values and manipulated variables shown corresponds to a course during a functioning tank ventilation path, ie there is no defective tank ventilation valve 5 or a leaking or clogged tank vent path.

The in 4th shown course for the electrical power consumption of the pressure booster 9 is exemplary and can therefore vary in the application of various principles to increase pressure. The evaluation thresholds shown (calibration constants) have to be adapted to the respective pressure increase principle.

• • Druckerfassungseinheiten 24 stromab Druckerhöhungseinheit 9; ODER
• • Druckerfassungseinheiten 25 stromauf Druckerhöhungseinheit 9

The diagnostic process (flush line diagnosis) can be carried out with the help of pressure sensors at the positions of the pressure detection units described below 24th , 25th be performed:

• • Pressure detection units 24th downstream pressure increasing unit 9 ; OR
• • Pressure detection units 25th upstream pressure booster unit 9

The pressure detection units 24th downstream of the pressure increasing unit 9 must be in the direction of flow of the flushing medium between the pressure booster 9 and the tank ventilation valve unit 1 are located. The sensor position based on the pressure detection unit is an example 24th shown.

The pressure detection units 25th upstream of the pressure booster unit 9 can be used as a diagnostic sensor, provided that the leak diagnostic unit 16 a blockage of the fresh air line to the sorption filter 8th can be made possible. The sensor position based on the pressure detection units is an example 25th shown. When using the pressure detection units 25th upstream of the pressure booster unit 9 result in comparison to the diagnostic process shown below using the pressure detection units 24th downstream of the pressure increasing unit 9 inverse (negative) pressure profiles.

Because to carry out the diagnosis with the upstream of the pressure booster 9 positioned pressure detection units 25th an active intervention in the tank ventilation strategy by closing the fresh air line to the sorption filter 8th If necessary, the diagnostic principle should be used in the further course with the help of the pressure detection units 24th downstream of the pressure increasing unit 9 be made clear.

The entire diagnostic process should be done by observing the pressure detection unit 24th while the tank ventilation functionality is activated. If activation of the tank ventilation function cannot be guaranteed in a driving cycle, there is the option of changing the control states of the electrical components involved (tank ventilation valve 1 / Booster unit 9 ) through the diagnostic functionality.

Alternatively, the electrical power consumption of the pressure booster unit 9 , analogous to the diagnostic process shown with the help of the pressure detection units 24th downstream of the pressure increasing unit 9 , can be used as an evaluation signal for flush line diagnosis.

The 4th shows a diagnostic process (divided into two sections I. and II ) for the nominal or faultless tank ventilation system. The person skilled in the art recognizes that the courses of the operating parameters, here the courses of the differential pressure 410 and the electrical power consumption 420 , within the first course I. and the second course II are different. When the pressure booster unit is activated 9 is the course of the differential pressure to the environment 410 small while at in section II tank vent valve switched off 5 , recognizable by the corresponding course 405 , the differential pressure to the environment 410 increases. There is therefore a properly connected connection to the tank ventilation valve unit 1 to the air intake path 10th of the internal combustion engine. The courses 410 and 420 in the sections I. and II are therefore different.

In the 5 and 6 on the other hand, the courses of the operating parameters are similar 410 respectively. 420 , and various sources of error can be concluded.

Section 1 in 5 shows the behavior of the nominal system of section 2 by the pressure curve downstream of the pressure booster unit or the electrical power consumption despite the open tank ventilation valve, whereby a blocked tank ventilation path can be concluded. This symptom A is diagnosed if the evaluation thresholds mentioned above are exceeded in section 1.

In another error, section shows II the pressure curve downstream of the pressure increasing unit 9 or the electrical power consumption despite the tank ventilation valve being closed 1 the behavior of the nominal system of section 1 , resulting in a leak in the tank ventilation path (e.g. caused by a faulty connection of the tank ventilation valve 1 with the air intake path 10th of the internal combustion engine), on the loss of the pressure increasing properties of the pressure increasing unit 9 or a faulty fresh air supply to the pressure booster 9 lets close. Symptom B is diagnosed if in section II the above-mentioned evaluation thresholds are undershot.

The invention is not limited to the exemplary embodiment described, but also encompasses other embodiments having the same effect. The description of the figures only serves to understand the invention.

Reference list

1

Tank vent valve unit

2nd

Electrical connection

3rd

check valve

4th

Bypass flow path

41

Path entrance

42

first end of path

5

Tank vent valve

6

poetry

7

Tank ventilation line

8th

Absorption filter

9

Pressure increasing unit

10th

Air intake path

101

an outside

11

Tank container

12th

Junction

14

Tank connection line

15

Air filter

16

Tank leakage diagnosis - component

17th

Air filter

20th

fuel

22

check valve

24th

Pressure detection unit downstream

25th

Pressure detection units upstream

100

Tank ventilation system

400

Control setpoint (open / closed) of the tank ventilation valve

405

Setpoint for controlling the pressure booster unit (on / off)

410

Differential pressure to the environment

420

Power consumption

Claims (16)

Tank ventilation valve unit (1) for use in a tank ventilation system (100) of an internal combustion engine, in particular for use in a flow path of a tank ventilation line (7), the tank ventilation valve unit (1) being arranged downstream of a pressure increasing unit (9) and upstream of an air intake path (10) of the internal combustion engine , full - A tank ventilation valve (TEV) (5) which is fluidly connected on the inlet side to a tank ventilation line (7) and on the outlet side to a connection point (12) of the air intake path (10), the tank ventilation valve (5) being in a controlled state, in particular in a currentless state closed state, prevents the passage of a flushing medium through the tank ventilation valve (5) and, in an open state, permits the passage of a flushing medium through the tank ventilation valve (5); and - A bypass flow path (4), wherein a path entrance (41) of the bypass flow path (4) can be fluidly connected to the tank ventilation line (7), a first path end (42) of the bypass flow path (4) being designed in such a way that a sealing connection between the first path end (42) and an outer side (101) of the air intake path (10) can be produced, the sealing connection having no fluid-conducting connection to the inside of the air intake path (10). Tank vent valve unit (1) after Claim 1 , characterized in that the sealing connection is designed such that an incorrect connection of the connection of the tank ventilation valve (5) with the connection point (12) results in the opening of the sealing connection. Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that the bypass flow path (4) is rigid with respect to the tank ventilation valve (5). Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that a second path end (41) of the bypass flow path (4) can be connected in a fluid-conducting manner to the inlet side of the tank ventilation valve (5). Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that the cohesively sealing connection is produced by means of a flange arranged on the outside of the air intake path (10), the bypass flow path (4) in the interior of the flange using at least one sealing ring ( 6) is connected in such a way that flushing medium flowing into the bypass flow path (4) cannot escape from the bypass flow path (4). Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that by a non-return valve (3), which is attached to the inlet or outlet side of the tank ventilation valve (5) such that the flushing medium only flow from the inlet side to the outlet side of the tank ventilation valve (5) can. Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that the cohesively sealing connection has at least one simple seal (6), preferably a double seal. Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that the tank ventilation valve unit (1) is electrically controlled via a map value of the internal combustion engine or via the flushing medium supplied to the internal combustion engine. Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that the tank ventilation valve unit (1) can be controlled by the level of at least one ambient pressure. Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that a pressure increasing unit (9) is provided in the tank ventilation valve unit (1). Tank ventilation valve unit (1) according to one of the preceding claims, characterized in that the fuel system comprises a sorption filter (8), in particular an activated carbon filter, which is connected to the tank ventilation valve unit (1). Method for diagnosing a tank ventilation system (100), in particular a connection of a tank ventilation valve unit (1) to an air intake path (10) of an internal combustion engine, the tank ventilation system (100) comprising a tank ventilation line (7), which is set up to flow a flushing medium from a sorption filter (8) to the intake tract, wherein at least one pressure increase unit (9) is arranged downstream of the sorption filter (8) and at least one pressure detection unit (24, 25) is arranged in a flow path of the tank ventilation line (7) downstream or upstream of the pressure increase unit (9) the tank ventilation line (7) downstream of the pressure detection unit (24, 25) with an input side of a tank ventilation valve unit (1) according to one of the Claims 1 to 11 is fluidly connected; the method comprising the steps S1 opening a tank ventilation valve (TEV) (5) of the tank ventilation valve unit (1) for a first period of time and detecting a first course of at least one operating parameter; S2 closing the tank ventilation valve (TEV) (5) of the tank ventilation valve unit (1) for a second period of time and detecting a second course of the at least one operating parameter; and S3 determining an error state of a connection of the tank ventilation valve unit (1) to the intake tract (10) and / or the tank ventilation line (7) based at least in part on the first and the second profile of the operating parameter. Procedure according to Claim 12 , characterized in that the operating parameter is a differential pressure to the environment of the pressure increasing unit (9). Procedure according to Claim 12 , characterized in that the operating parameter is an electrical power consumption of the pressure increasing unit (9). Procedure according to one of the Claims 13 or 14 , characterized in that the fault condition of the connection of the tank ventilation unit (1) is diagnosed on the basis of the observation that the first course of the differential pressure to the surroundings of the pressure increasing unit (9) is qualitatively similar to the second course of the differential pressure to the surrounding pressure increasing unit (9). Motor vehicle, comprising a tank ventilation valve unit (1) for use in a tank ventilation system (100) of an internal combustion engine according to one of the Claims 1 to 11 .

Images