WO2020078789A1

WO2020078789A1 - Tank ventilation valve unit

Info

Publication number: WO2020078789A1
Application number: PCT/EP2019/077328
Authority: WO
Inventors: Thomas Pichler; Tobias Hirthammer; Roland HAUFLER
Original assignee: Vitesco Technologies GmbH
Priority date: 2018-10-15
Filing date: 2019-10-09
Publication date: 2020-04-23
Also published as: DE102018217630A1

Abstract

The invention relates to a tank ventilation valve unit (1) for use in a tank ventilation system (100) of an internal combustion engine, particularly for use in a flow path of a tank ventilation line (7). The tank ventilation valve unit is arranged downstream of a pressure booster (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 fluidically connected on the input side to a tank ventilation line (7) and on the output side to a connecting point of the air intake path (10). In a closed state, the tank ventilation valve (5) inhibits 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) is provided, wherein a path inlet into the bypass flow path (4) can be fluidically connected 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 made between the first path end and an outer side of the air intake path (10), with the sealing connection having no fluidic connection to the interior of the air intake path (10). The invention also relates to a method for diagnosing a tank ventilation system, particularly a connection of a tank ventilation valve unit to an air intake path of an internal combustion engine.

Description

description

Tank vent valve unit

The invention relates to a tank ventilation valve unit for use in a tank ventilation system

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 available for

Pollutant emissions are responsible. These sources can include, for example, vapors from a fuel tank of the internal combustion engine.

Fuels such as super gasoline, which in the

Fuel tank can be stored, have a number of volatile hydrocarbons. These include, for example, methane, butane and propane. To advance the fuel tank when there is a change in a volume of fuel

To protect mechanical damage 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 connected to the environment via a connection of the activated carbon filter sucked in, which entrains the temporarily stored fuel and feeds the combustion. The amount of gas sucked in is controlled via the tank ventilation valve in such a way that the

Activated carbon filter is sufficiently flushed with air and that, 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

Functionality of a tank ventilation system

ensure, i.e. that among other things one in one

Tank ventilation system installed defective tank ventilation valve or leaking or blocked pipes must be recognized as defective by suitable diagnostics.

It is known from the prior art that checking the functionality of that area of the

Tank ventilation path, which is downstream between the pressure booster unit to the discharge point in the

Air intake path of the internal combustion engine is located below

Using a tank leakage diagnosis component, such as a shut-off valve and one

Pressure detection unit can be performed, 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. To now the

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 can be diagnosed.

It proves to be a disadvantage that almost at the connection point of the tank ventilation valve after the air filter

Ambient pressure prevails, so that even at high

Mass flows in the area after the air filter only set a very low pressure drop, which means that only certain Operating points of the internal combustion engine (very high engine loads) a meaningful differential pressure to the ambient pressure level can be measured at 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.

To date, diagnosis of the above-mentioned connection point has only been possible in very limited operating points of the

Internal combustion engine at high engine loads with high

Air mass flows and only possible through active control of the tank ventilation valve, whereby an evaluation of the differential pressure to the environment that occurs at high engine loads can only be realized by the sensor system if the vacuum-generating point is downstream of the connection point in the air intake path of the internal combustion engine.

The present invention is based on the object of at least partially overcoming the problems known from the prior art and an improved tank ventilation valve unit for use in a tank ventilation system

To provide internal combustion engine and an improved method for diagnosing a tank ventilation system, which is very reliable one in one with simple means

Tank ventilation system installed defective tank ventilation valve or leaky or clogged lines can be detected by suitable diagnostics, the method should be as simple as possible, efficient and inexpensive.

The invention solves this problem by means of a

Tank vent valve unit for use in one

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 vent valve unit for use in one

Tank ventilation system of an internal combustion engine, in particular for use in a flow path of a tank ventilation line. Here is 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 includes a tank ventilation valve and one

Bypass flow path. The tank vent valve is

fluid-conducting on the inlet side with a tank ventilation line and with a connection point on the outlet side

Air intake path connectable. In a controlled,

in particular in a currentlessly 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 permits the passage of a flushing medium through the tank ventilation valve. A first path end of the

The bypass flow path is designed in such a way that a sealing connection can be established between the first path end and an outside of the air intake path, the sealing connection not having any fluid-conducting connection to the inside of the air intake 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 is not required.

Through the direct connection of the tank ventilation valve to the air intake path of the internal combustion engine, a Propagation model for modeling the mass flow from the tank ventilation valve to the connection point in the air intake path is 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 in such a way that an incorrect connection of the connection of the tank ventilation valve to the connection point results in the opening of the connection connected to the air intake pipe in particular via a seal (e.g. an 0-ring seal).

In a particularly preferred embodiment, the

Bypass flow path is rigid with respect 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 produced by means of a flange arranged on the outside of the air intake path, the

Bypass flow path is connected in the interior of the flange by means of at least one sealing ring in such a way that in the

Bypass flow path flowing flushing medium can not escape from the bypass flow path.

In a preferred embodiment, a

Check valve, which on the input side or

attached to the tank vent valve on the outlet side, it can be ensured that the flushing medium only flows from the inlet side to the outlet 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 vent valve unit is based on the

Mass flow of the flushing medium supplied to the internal combustion engine or the level of at least one ambient pressure can be controlled.

In a particularly advantageous embodiment

Tank vent line path upstream of the

Tank vent valve unit provided a pressure increasing unit.

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 one

Air intake path of an internal combustion engine another

Subject of the invention. This includes

Tank ventilation system 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 vent line is downstream of the

Pressure detection unit with an input side of a

tank vent valve unit according to the invention fluidly connected. The process comprises the following steps:

S1 Opening a tank ventilation valve of the

Tank vent valve unit for a first

Period and detection of 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 recording 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, forms a further subject of the invention, the

Tank ventilation valve unit is 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 have and can also be used in combination with features of other developments described above and are not intended to limit the invention in any form.

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

Fig. 1 shows an example of a schematic representation of the

Tank ventilation;

Fig. 2 shows a schematic representation of a

tank ventilation system according to the invention with bypass in a first embodiment of the present invention;

Fig. 3 shows a schematic representation of a

tank ventilation system with bypass according to the invention in a second embodiment of the present invention;

4 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 sequence in two

Command values for 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 Command values in the event of a pressure loss or a faulty open line connection in the tank ventilation system.

1 shows an example of a tank ventilation system 100 of an internal combustion engine, not shown, with a

Tank ventilation valve unit 1. The tank ventilation system 100 comprises a tank container 11 for holding fuel 20, which is connected in a fluid-conducting manner to a sorption filter 8 via a tank connection line 14. The sorption filter 8 can be designed as an activated carbon filter, which can temporarily store volatile components of evaporating fuel through adsorption and desorption. The sorption filter 8 is also connected in a fluid-conducting manner to the air intake path 10 connected upstream of the internal combustion engine via a tank ventilation line 7 and flushing medium. The air intake path 10 supplies the internal combustion engine with filtered ambient air via an air filter 17. About the

Tank connection line 14 can thus conduct volatile components of fuel 20, such as hydrocarbons, from tank tank 11 into sorption filter 8, stored and from there via a clocked or linearly controlled

The tank ventilation valve unit 1 and the tank ventilation line 7 are metered to an air intake path 10 of the internal combustion engine for combustion.

To realize a pressure gradient and one with it

accompanying mass flow between the ambient pressure and the point of introduction into the air intake path 10 is one

Pressure increasing unit 9, for example a rinsing pump, is provided. At least one, in the exemplary embodiment shown, two pressure detection units 24, 25 are arranged within the tank ventilation line 7 both upstream and downstream of the pressure increasing unit 9. The

Pressure increase unit 9 is designed in such a way that there is a continuous line connection from the air filter 15 upstream to the sorption filter 8 up to the connection to the tank ventilation valve unit 1. By executing a tank leakage functionality with the help of a Tank leakage —diagnosis - component 16 and the

Pressure detection units 24, 25 can ensure the operability of the tank ventilation system 100 including the fuel tank 11 and the tank ventilation line 7 up to the connection to the

Tank vent valve unit 1 can be determined.

The tank ventilation line 7 has a check valve 22, which serves to unidirectionally flow the mass

Ensure air intake path 10 of the internal combustion engine.

To regenerate the adsorption filter 8, the

Tank ventilation valve 1 is opened, so that due to the negative pressure prevailing in the air intake path 10, air is sucked into the atmosphere through the adsorption filter 8, as a result of which the hydrocarbons accumulated in the adsorption filter 8 are sucked into the tank ventilation line 7 and fed to the internal combustion engine.

The tank ventilation valve unit 1, which can be designed as a switching or linear valve, can be of one

Engine control can be controlled by means of a pulse width modulated (PWM) signal and regulates the flushing medium from the sorption filter 8 to the inlet points in the air intake path 10 of the internal combustion engine. According to the invention, it is provided that the engine control system inter alia for the current one

Operating state a setpoint for the mass flow and a current intake manifold pressure determined using a pressure sensor, not shown in the intake tract. From the resulting pressure drop between the pressure increase unit 9 and the pressure at the point of introduction in the air intake path 10 of the internal combustion engine, the pulse-width modulated (PWM) signal for controlling the tank ventilation valve 1 is determined from the predetermined mass flow and is relevant for the current operating state of the

Amount of fuel to be injected into the internal combustion engine is calculated.

Then, for the above-mentioned point of introduction of the tank ventilation into the air intake path 10 of the internal combustion engine, the delay time due to the opening of the tank ventilation valve 1 of the mass flow supplied to the combustion is calculated and a fuel correction is made on the basis of the plausibility which has been learned (modeled) with the aid of the two pressure detection units 12 and is plausible by means of a lambda control deviation

Hydrocarbon concentration of the mass flow calculated. Accordingly, the internal combustion engine has a lambda controller not shown in FIG. 1.

In Figures 2 and 3 are two different examples

Embodiments of an inventive

Tank vent valve unit 1 shown. The

Tank vent valve unit 1 includes this

Tank ventilation valve 5 and an electrical connection 2 connected to it. According to the invention, a bypass flow path 4 is provided which, for example, as shown in FIG. 2, branches off from the tank ventilation line 7 and via a separate line past the tank ventilation valve 5 to a path entrance 41 a first deposit end 42, or, as shown in FIG. 3, in a tank ventilation line 7 which surrounds the entire tank ventilation valve 5.

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

By integrating bypass flow path 4 into the

Tank ventilation valve unit 1 is closed in a pressure-tight manner when the tank ventilation valve 5 is correctly connected to the air intake path 10 of the internal combustion engine. Of the

Bypass flow path 4 is cohesive and thus connected to the tank ventilation valve 5 without plug or screw connections.

Both the connection point 12 and the first path end 42 of the bypass flow path 4 are connected to the air suction path 10 or to the tank ventilation valve 5 via a seal 6, preferably also via a double seal. The tank ventilation valve unit 1 is designed such that if the tank ventilation valve 5 is connected incorrectly at the connection point 12,

Air intake path 10 of the internal combustion engine automatically opens a further bypass flow path 4 upstream or downstream of the tank ventilation valve 5 in the direction of ambient pressure.

A check valve 3 is shown in FIGS. 2 and 3 at different positions

Tank vent valve unit 1 integrated.

Because of this constructive property of

Tank vent valve unit 1 may have an incorrectly connected tank vent valve 5 connected to the air intake path 10 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 course of the respective values and manipulated variables shown in FIG. 4 corresponds to a course during a

functional tank ventilation path, i.e. there is no defective tank ventilation valve 5 or a leaking or blocked tank ventilation path.

The course shown in Figure 4 for electrical

Power consumption of the pressure increasing unit 9 is exemplary and can therefore vary when different principles are used to increase the pressure. The evaluation thresholds shown (calibration constants) apply to the respective

Adjust pressure increase principle.

The diagnostic process (flushing pipe diagnosis) can be found under

Pressure sensors can be carried out at the positions of the pressure detection units 24, 25 described below:

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

Pressure increasing unit 9

The pressure detection units 24 downstream of the

Pressure increase unit 9 must be in the flow direction of the

Flushing medium between the pressure increasing unit 9 and the tank ventilation valve unit 1. The sensor position using the pressure detection unit 24 is an example

shown.

The pressure detection units 25 upstream of the

Pressure increase unit 9 can be used as a diagnosis sensor, provided that the leak diagnosis unit 16 can block the fresh air line to the sorption filter 8. The sensor position is shown by way of example using the pressure detection units 25. When using the pressure detection units 25 upstream of the

Pressure increase unit 9 results in comparison to the diagnostic procedure shown below by means of the

Pressure detection units 24 downstream of the pressure increasing unit 9 inverse (negative) pressure profiles.

Because to run the diagnosis with the upstream of the

Pressure increasing unit 9 positioned

Pressure detection units 25 an active intervention in the

Tank venting strategy by closing the

Fresh air line to the sorption filter 8 is necessary, the diagnosis principle will be clarified in the further course with the aid of the pressure detection units 24 downstream of the pressure increase unit 9.

The entire diagnostic process should be carried out by observing the

Pressure sensing unit 24 while activated

Tank ventilation functionality can be performed. If activation of the tank ventilation function cannot be guaranteed in a driving cycle, it is possible to change the control states of the electrical systems shown below Components (tank ventilation valve 1 / pressure booster unit 9) to request through the diagnostic functionality.

Alternatively, the electrical power consumption of the

Pressure increasing unit 9, analogous to that shown

Diagnostic course with the help of the pressure detection units 24 downstream of the pressure increasing unit 9 can be used as an evaluation signal for the flushing line diagnosis.

FIG. 4 shows a diagnostic procedure (divided into two sections I and II) for the nominal or error-free one

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, are different within the first course I and the second course II. When the pressure increasing unit 9 is activated, the course of the differential pressure to the environment 410 is small, while when the tank ventilation valve 5 is switched off in section II, recognizable by the corresponding course 405, the differential pressure to the environment 410 increases. There is therefore a properly connected connection of the tank ventilation valve unit 1 to the

Air intake path 10 of the internal combustion engine. The courses 410 and 420 in sections I and II are therefore different.

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

Section 1 in FIG. 5 shows the behavior of the nominal system from section 2 due to the pressure curve downstream of the pressure increase unit or the electrical power consumption despite the tank ventilation valve being open, as a result of which 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 fault, section II shows the pressure curve downstream of the pressure increasing unit 9 or the electrical one Power consumption despite the tank ventilation valve 1 being closed, the behavior of the nominal system from section 1, which means that there is a leak in the tank ventilation path (for example caused by a faulty connection of the tank ventilation valve 1 to the air intake path 10 of the internal combustion engine), on the loss of the pressure increase properties of the

Pressure increasing unit 9 or a faulty one

Fresh air supply to the pressure increasing unit 9 can be closed. Symptom B is diagnosed if the above evaluation thresholds are not reached in Section II.

The invention is not limited to the exemplary embodiment described, but also includes others having the same effect

Embodiments. The description of the figures only serves to understand the invention.

Reference list

1 tank vent valve unit

2 Electrical connection

3 check valve

4 Bypass flow path

41 Path entrance

42 first end of path

5 tank vent valve

6 seal

7 tank ventilation line

8 absorption filters

9 pressure increasing unit

10 air intake path

101 an outside

11 tank containers

12 connection point

14 tank connection line

15 air filters

16 Tank leakage —diagnosis - component

17 air filter

20 fuel

22 check valve

24 pressure detection unit downstream

25 pressure detection units upstream

100 tank ventilation system

400 control setpoint (open / closed) of the

Tank vent valve

405 Setpoint for controlling the pressure increasing unit

(on off )

410 differential pressure to the environment

420 power consumption

Claims

1. Tank ventilation valve unit (1) for use in one

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 vent valve unit (1) downstream one

Pressure increasing unit (9) and one upstream

Air intake path (10) of the internal combustion engine is arranged, comprising a tank ventilation valve (TEV) (5), which can be fluidly connected on the input side to a tank ventilation line (7) and on the output side to a connection point (12) of the air intake path (10), the tank ventilation valve (5) in one

controlled state, in particular in a de-energized 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), a path entrance

(41) of the bypass flow path (4) with the

Tank ventilation line (7) can be connected in a fluid-conducting manner, a first path end (42) of the

Bypass flow path (4) is designed such that a sealing connection between the first path end

(42) and an outside (101) of the air intake path (10) can be produced, the sealing connection not having any fluid-conducting connection to the inside of the

Has air intake path (10).

2. Tank ventilation valve unit (1) according to 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) causes the sealing connection to open.

3. tank ventilation valve unit (1) according to any one of the preceding claims, characterized in that the bypass flow path (4) relative to the

Tank vent valve (5) is rigid.

4. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that a second path end (41) of the bypass flow path (4) can be fluidly connected to the inlet side of the tank ventilation valve (5).

5. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that the cohesively sealing connection by means of a flange arranged on the outside of the air intake path (10)

The bypass flow path (4) is connected inside the flange by means of at least one sealing ring (6) in such a way that flushing medium flowing into the bypass flow path (4) does not come out of the

Bypass flow path (4) can emerge.

6. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that a check valve (3) which is attached to the tank ventilation valve (5) on the input side or output side such that the flushing medium can only flow from the input side to the output side of the tank ventilation valve (5).

7. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that the cohesively sealing connection has at least one simple seal (6), preferably a double seal.

8. Tank ventilation valve unit (1) according to one of the

preceding claims, characterized in that the tank ventilation valve unit (1) electrically via a Map value of the internal combustion engine or via the flushing medium supplied to the internal combustion engine is controlled.

9. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that the tank ventilation valve unit (1) can be controlled by the level of at least one ambient pressure.

10. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that in the tank ventilation valve unit (1)

Pressure increasing unit (9) is provided.

11. Tank ventilation valve unit (1) according to one of the

The preceding claims, characterized in that the fuel system comprises a sorption filter (8), in particular an activated carbon filter, with the

Tank vent valve unit (1) is connected.

12. 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 configured to conduct a flow of a flushing medium from a sorption filter (8) to the intake tract, downstream of the sorption filter ( 8) at least one pressure increasing unit (9) and downstream or

at least one pressure detection unit (24, 25) is arranged upstream of the pressure increasing unit (9) in a flow path of the tank ventilation line (7), the tank ventilation line (7) downstream of the

Pressure detection unit (24, 25) is fluidly connected to an input side of a tank ventilation valve unit (1) according to one of Claims 1 to 11; the procedure includes the steps 51 opening a tank ventilation valve (TEV) (5) of the tank ventilation valve unit (1) for a first period of time and recording a first course of at least one operating parameter;

52 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

53 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) at least in part on the basis of the first and the second course of the operating parameter.

13. The method according to claim 12, characterized in that the operating parameter is a differential pressure to the environment of the pressure increasing unit (9).

14. The method according to claim 12, characterized in that the operating parameter is an electrical power consumption of the pressure increasing unit (9).

15. The method according to any one of 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 environment of the pressure increasing unit (9) qualitatively the second course of the differential pressure to the environment pressure increasing unit (9) is the same.

16. 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 claims 1 to 11.