DE102009036265A1 - Method for testing leakage of tank system of internal combustion engine of e.g. hybrid vehicle, involves implementing leakage testing based on comparison of detected and adjusted pressures and/or temporal changing of detected pressure - Google Patents

Abstract

The method involves arranging two tank check valves (38, 42) in tank vent pipes (30, 32, 34), respectively. A certain pressure in a partial space of a tank system is adjusted by the check valves and a regeneration valve (50) during operation of an internal combustion engine. The pressure in the partial space of the tank system is detected after start of operation of the engine. Leakage testing is implemented based on comparison of the detected pressure with the adjusted pressure and/or temporal changing of the detected pressure.

Description

The The invention relates to a method for leak testing a tank system, in particular a tank system of a motor vehicle.

At the Operation of motor vehicles containing volatile fuels It is used to operate their internal combustion engines future, the evaporation and refueling emissions depending on the given market requirements and legal requirements reliable to regulate.

In the US, for example, a separation of storage tanks for refueling emissions and for evaporative emissions is required. Such a tank system is exemplary in the US 5,111,795 disclosed. In this conventional tank-venting tank system, there are provided on the fuel tank two vent lines for the refueling emissions which are combined at a multi-way valve, of which two further lines lead to a first storage arrangement and a second storage arrangement for adsorbing hydrocarbons from the volatile fuel vapors to lead. Depending on the operating situation, the multi-way valve is controlled so that the refueling emissions are fed to one storage or the evaporation emissions are fed to the other storage. Both storage arrangements are connected via separate purge lines to an intake tract of the internal combustion engine. The US 5,111,795 deals in particular with the design of the multi-way valve, special leak tests of the entire tank system are not described.

It exists in the field of automotive engineering in principle of Desire, as simple as possible, lightweight and inexpensive Use components. Of course, this also applies to the fuel tank. There is therefore a need for a tank system of of the type mentioned above with two separate memories for the refueling and the evaporative emissions, with a simpler Fuel tank can be realized, only for low pressures is designed.

At the Operation of motor vehicles containing volatile fuels It is used to operate their internal combustion engines further required in the future, the tank system of the motor vehicle regularly check for leaks with on-board equipment (on-board diagnosis, OBD). In doing so, the control device must be able be, even leaks in the order of 0.5 mm diameter reliably detect.

The DE 101 01 257 A1 discloses a tank system and method for leak testing in this tank system. The tank system includes a fuel fillable tank via a filler neck, a first breather pipe, an activated carbon canister connected to the first breather pipe, a breather pipe connected to the activated carbon canister for scavenging the activated carbon canister, and an intake pipe connecting the activated carbon canister to the intake manifold of the engine downstream of the throttle valve. In the first vent line, a valve is arranged which opens the first vent line during a refueling operation of the tank and is otherwise closed. The tank is also connected via a second vent line to the intake of the engine downstream of the throttle. In this second vent line, a control valve for controlling the overpressure / underpressure in the tank and a shut-off valve for closing the second vent line during a refueling operation or a strong inclination of the tank are provided. For leak testing, the second vent line, the vent line of the activated carbon canister and the suction line are closed and opened the first vent line. By means of a tank pressure sensor, the pressure in the entire space of the tank system comprising the tank, the activated carbon container and the first vent line is then detected and compared with a stored reference value

From the DE 102 04 132 A1 a leak diagnostic device is known, which is also referred to as DTML (Detection Module Tank Leak Diagnostic Module). This module is arranged, for example, on an activated carbon container of a tank ventilation system and has in particular a reference leak with a diameter of, for example, 0.5 mm and a pressure source for pressurizing the tank system to be tested with overpressure. It may be of particular advantage to use a reference leak that corresponds in geometry and dimensions to a standard from the Californian Air Resources Board (CARS), as described in US Pat DE 103 60 337 A1 is proposed. By means of the pump serving as a pressure source, the reference leak is pressurized via a switching means either the tank system or for calibration. The presence and size of a leak in the tank system can then be determined from the time course and the size of the pump flow which occurs when the tank system is pressurized.

In new legislation, especially in the US, a separate leak test in different sub-areas of the tank system is required, at least for special types of vehicles such as hybrid vehicles. There is therefore a need for a method for leak testing a tank system, which includes the meets the latest legal requirements and can perform leak diagnosis in sub-areas of the respective tank system.

It It is an object of the present invention to provide a method of leak testing a tank system that has two separate storage for evaporative emissions and for refueling emissions.

These Task is solved by a method for leak testing a tank system with the features of claim 1. Advantageous Embodiments and further developments of the invention are the subject the dependent claims.

The Tank system in which the leak test of the invention to be used, has a tank for receiving a fuel for an internal combustion engine, a first memory with a Storage medium for at least temporary binding of evaporative emissions (Evaporative Emission, EVAP), a first memory with the tank connecting first tank vent line, one the first Memory with an intake tract of the internal combustion engine connecting first purge line, a second memory with a storage medium for at least temporary binding of refueling emissions (onboard refueling Vapor Recovery System, ORVR), a second tank with the tank connecting second tank vent line, one the second Memory with the intake of the engine connecting second purge line and one in the first purge line and / or the second purge line arranged Regenerierventil on.

The Provide two Tankabsperrventilen in the two tank vent lines to the first memory or second memory allows a Optimization of the ventilation processes of the tank and rinsing the memory. Especially The control device may be the tank system in such a way operate, on the one hand, the pressure in the tank below a predetermined Limit, so advantageously not necessarily a pressure tank must be used, and on the other hand, the loading levels the memory remain below predetermined limits, so that a Breakthrough of the memory with the associated negative consequences such as fuel emissions to the atmosphere and odor can be avoided. In other words, the tank system of the Invention with a simply constructed fuel tank (eg plastic tank) and at the same time offers a secure protection of the Environment before fuel emissions.

One such tank system is used in a particularly advantageous manner if a separation of the storage for the evaporative emissions and refueling emissions are required (such as in the US) and on the other hand only small flush volumes for the memories are available (such as at Hybrid vehicles and vehicles with automatic start / stop).

Under The term "memory" is used in this context Invention both individual storage containers and arrangements understood from several storage containers. When the stores are for example, charcoal canisters.

to Leak test of this tank system will be in the first Tank vent line a first Tankabsperrventil and in the second tank vent line a second Tankabsperrventil arranged so that during operation of the internal combustion engine through the first tank shut-off valve, the second tank shut-off valve and the regeneration valve has a certain pressure in at least one Subspace of the tank system is set. After a start of operation The internal combustion engine will then be a pressure in the at least one Subspace of the tank system recorded and a leak test based a comparison of the detected pressure in the at least one subspace of the tank system with that during the previous operation the internal combustion engine set pressure and / or a temporal Change of the detected pressure in the at least one subspace carried out of the tank system.

The Leak test according to the invention Tanksystems is made possible by simply using Help the existing in the tank system valves during the Operating the internal combustion engine a certain pressure in at least a subspace of the tank system is set and this pressure then recorded and evaluated after a start of operation. The anyway needed control strategy for venting operations the tank and flushing the store will be here advantageously also for the leak test the tank system used by in the tank system or in at least a subspace of the tank system set a certain pressure and at the next start of operation of the internal combustion engine recorded and evaluated. For evaluation, the detected pressure compared with the previously set pressure and / or a temporal change be assessed the detected pressure. If there is too much deviation between the actually detected pressure value and that due to the Presets expected pressure value or excessive pressure drop In a short time can be closed to a leak in the respective tank room.

The "pressure" which is set, detected and evaluated in the tank system or in the at least one subspace of the tank system is an overpressure or a negative pressure in comparison to the At atmospheric pressure outside the tank system.

Preferably the leak test in the at least one subspace of the Tank system is performed after a cold start of the internal combustion engine. On the one hand, this has the advantage that immediately after starting the internal combustion engine diagnoses the tightness of their tank system is and operating an internal combustion engine with a leakage can be prevented in the tank system, and prevail on the other hand after the cold start of the engine predefined and known Conditions that are easily and reliably verifiable so that the leak test runs reliably can be.

In an embodiment of the invention, the at least one subspace of the tank system contain a first subspace containing the tank, the first and the second tank vent line and the first and comprises the second memory. In this case, the leak test in the first subspace with closed Regenerierventil and at open first and second Tankabsperrventil be performed.

Of the Pressure in the first subspace is, for example, by means of a first Pressure sensor detected on the tank, the first tank vent line and / or the second tank vent line is arranged. alternative or additionally, the pressure in the first subspace may also be be detected by a second pressure sensor connected to the first memory, the second memory, the first purge line and / or the second purge line is arranged.

In In another embodiment of the invention, the at least one Subspace of the tank system included a second subspace, which is the tank and the first and the second tank vent line between the tank and first and second Tankabsperrventil includes. In this Case, the leak test in the second subspace when closed first and second Tankabsperrventil be performed. The pressure in the second subspace can, for example, by means of a first pressure sensor to be detected on the tank, the first Tank vent line and / or the second tank vent line is arranged.

In a still further embodiment of the invention, the at least a subspace of the tank system contains a third subspace, the first and the second memory and the first and the second Tank vent line between the respective memory and the first and second Tankabsperrventil. In this Case, the leak test in the second compartment with the first closed and second Tankabsperrventil and closed Regenerierventil be performed. The pressure in the third compartment can be detected, for example, by means of a second pressure sensor, at the first memory, the second memory, the first purge line and / or the second purge line is arranged.

In Another embodiment of the invention, the leak test in the at least one subspace of the tank system preferably after a test of the functional capabilities) of the first Tankabsperrventils, the second Tankabsperrventils, the regeneration valve, the first pressure sensor and / or the second pressure sensor performed become. Through this preliminary check of the functionality (s) will ensure that the leak test is done properly and can be reliably performed. With others Words are first used in the leak test some components of the tank system to their proper Functionality checked to ensure that the subsequent leak test is the right one Result achieved.

In Yet another embodiment of the invention, the leak test in the at least one subspace of the tank system only in a closed Tank cap of the tank is performed. The tank system is with an open tank lid (eg during a refueling process) Of course not tight, so in this case a leak test would make no sense.

Furthermore can the leak test in the at least one subspace of the Tank system preferred after a leak test of a gas cap and / or a filler neck of the tank become.

The Method for leak testing a tank system is in particularly advantageous in motor vehicles with a tank system Can be used with tank ventilation, the separate storage for have the evaporative emissions and the refueling emissions. Special advantages can be found especially in hybrid vehicles revealed that an onboard diagnostic method with the possibility require separate analysis of different subspaces.

Above as well as other features, advantages and applications of the invention will become apparent from the following description of preferred, non-limiting embodiments below With reference to the accompanying drawings better understandable. Show:

1 a schematic representation of a first example of a tank system with tank ventilation, wherein the method for leak testing according to the present invention in an advantageous Way is applicable;

2 a flowchart for illustrating the basic sequence of a leak test of the tank system of 1 according to the present invention;

3 a schematic representation of a second example of a tank system with tank ventilation, in which the method for leak testing according to the present invention is advantageously applicable; and

4 a schematic representation of a third example of a tank system with tank ventilation, in which the method for leak testing according to the present invention is advantageously used.

Referring to 1 First, the structure and operation of a first tank system with tank ventilation on the example of a tank system for a motor vehicle will now be explained in more detail. It should be noted that the invention can be used in the same way in tank systems of other applications.

The tank system of the motor vehicle includes a tank 10 to pick up a volatile fuel (gasoline, diesel, etc.) 12 , The fuel 12 can via a filler neck 14 in the tank 10 be filled with a gas cap 16 is closable. A fuel cap sensor (not shown) detects if the fuel cap 16 is open or closed.

The fuel 12 gets out of the tank 10 by means of a fuel pump 18 via a fuel supply line 20 at least one injection valve 22 fed. The injectors 22 open in a known manner, for example, downstream of a throttle 24 in an intake tract 26 the internal combustion engine 28 , Depending on the type of internal combustion engine 28 can the injectors 22 but also elsewhere in the intake system 26 or directly into the internal combustion engine 28 lead. Also needs the fuel supply line 20 the fuel 12 from the tank 10 not necessarily an injection valve 22 respectively. Depending on the type of internal combustion engine and on the type of fuel, other numbers, variants and arrangements are also conceivable here.

The Tank 10 is also with a vent main line 30 provided by which during a refueling operation of the tank 10 or during normal operation of the internal combustion engine 28 resulting fuel vapors from the tank 10 can be dissipated. This bleeder main 30 branches into a first vent branch line 32 and a second vent branch line 34 , The bleeder main 30 and the first vent branch line 32 Form the first vent line of the invention and the main vent line 30 and the second vent branch line 34 form the second vent line of the invention.

The first vent line 30 . 32 leads to a first memory 36 in which the fuel vapors, more precisely the hydrocarbons in the volatile fuel vapors, from the tank 10 be tied at least temporarily. The first store 36 For example, it may be configured as one or more activated charcoal canisters for reversibly binding the volatile hydrocarbons. This first store 36 serves to record the evaporative emissions of the fuel 12 during operation of the internal combustion engine 28 ,

In the first vent branch line 32 is a first tank shut-off valve 38 arranged. This first tank shut-off valve 38 is preferably a closed in the de-energized state valve, so no creeping entry of evaporative emissions in the first memory 36 can take place. This would be particularly disadvantageous if the first memory 36 has no more capacity and therefore it could, for example, come to a breakthrough of the activated carbon canister or.

The second vent line 30 . 34 leads to a second memory 40 in which the fuel vapors from the tank 10 be tied at least temporarily. The second memory 40 may also be configured, for example, as one or more activated carbon canisters for reversibly binding the volatile hydrocarbons. This second memory 40 serves to record the refueling emissions of the fuel 12 during refueling of the tank 10 over the filler neck 14 ,

In the second vent branch line 34 is a second tank shut-off valve 42 arranged. This second tank shut-off valve 42 is analogous to the first Tankabsperrventil preferably also closed in the de-energized state valve, so no creeping entry of evaporative emissions in the second memory 42 can take place.

The first store 36 is on its downstream side via a first Spülzweigleitung 44 and a scavenging main 48 downstream of the throttle 24 with the intake tract 26 the internal combustion engine 28 connected. Similarly, the second memory is 40 on its downstream side via a second Spülzweigleitung 46 and the rinse main 48 downstream of the throttle 24 with the intake tract 26 the internal combustion engine 28 connected.

In or on this Spülhauptleitung 48 is a regeneration valve 50 arranged.

In addition, the first memory 36 via a first ventilation line 52 connected to the atmosphere. In or on this first ventilation line 52 is a first vent valve 54 intended.

Similarly, the second memory is 40 via a second ventilation line 56 connected to the atmosphere. In or on this second ventilation line 56 is a second vent valve 58 intended.

The Tank system can use the provided valves in different Subspaces are subdivided.

For example, a first subspace defining the tank can be defined 10 , the first tank vent line 30 . 32 , the second tank vent line 30 . 34 , the first store 36 and the second memory 40 includes. In addition, this first subspace generally also includes the first purge line 44 . 48 to the regeneration valve 50 , the second purge line 46 . 48 up to the regeneration valve, the first ventilation line 52 to the first vent valve 54 , the second ventilation line 56 to the second vent valve 58 and the filler neck 14 to the fuel cap 16 ,

Further, for example, a second subspace can be defined, which is the tank 10 , the first tank vent line 30 . 32 until the first tank shut-off valve 38 and the second tank vent line 30 . 34 to the second tank shut-off valve 42 includes. In addition, this second compartment generally also includes the filler neck 14 to the fuel cap 16 ,

In addition, for example, a third subspace defining the first memory may be defined 36 , the second memory 40 , the first tank vent line 32 between the first tank stop valve 38 and the first memory 36 and the second tank vent line 34 between the second tank shut-off valve 42 and the second memory 40 includes. In addition, this third subspace generally also includes the first purge line 44 . 48 to the regeneration valve 50 , the second purge line 46 . 48 up to the regeneration valve, the first ventilation line 52 to the first vent valve 54 and the second vent line 56 to the second vent valve 58 ,

There is also a first pressure sensor 60 on the tank 10 and / or the main vent line 30 arranged to detect a pressure in the tank system, in particular in the first subspace or in the second subspace of the tank system.

A second pressure sensor 62 is at the second rinse branch line 46 arranged to detect a pressure in the tank system, in particular in the first subspace or in the third subspace of the tank system.

The two pressure sensors 60 . 62 are with a control device 64 coupled.

The first tank shut-off valve 38 for the first tank vent line 30 . 32 , the second tank shut-off valve 42 for the second tank vent line 30 . 34 , the first ventilation valve 54 for the first ventilation line 52 of the first memory 36 , the second ventilation valve 58 for the second ventilation line 56 of the second memory 40 and the regeneration valve 50 for the flushing line 48 be from the controller 64 driven.

The control of the valves 38 . 42 . 50 . 54 . 58 done by the controller 64 in particular such that the pressures in the various subspaces of the tank system during operation of the internal combustion engine 28 be set to predetermined values. For this purpose, it is advantageous if the first and second Tankabsperrventil 38 . 42 can be controlled independently of each other.

In normal operation of the internal combustion engine 28 be through the control device 64 both tank shut-off valves 38 . 42 , both ventilation valves 54 . 58 and the regeneration valve 50 closed. In this way, the fuel vapors can only up to the two Tankabsperrventilen 38 and 42 from the tank 10 escape, leaving yourself in the tank 10 generally build up an overpressure.

To also simpler fuel tank for the tank 10 To be able to use, for example, plastic container instead of stainless steel pressure tanks, the pressure in the tank 10 held by suitable control strategies below a predetermined limit.

For pressure reduction in the tank 10 opens the control device 64 the first tank shut-off valve 38 and the first vent valve 54 while the second tank shut-off valve 42 , the second ventilation valve 58 and the regeneration valve 50 be controlled closed. In this way, the volatile fuel vapors from the tank 10 through the main vent line 30 and the first vent branch line 32 to the first memory 36 be removed, so the pressure in the tank 10 is reduced. In this case, the hydrocarbons in the fuel vapors in the first memory 36 bound and not through the first vent line 54 delivered to the atmosphere.

Referring to 2 (Sub-Figures 2A and 2B), a rough procedure of a leak test for the above-described tank system according to the present invention will now be explained.

After a start of the internal combustion engine 28 In step S100, for example, when starting a motor vehicle, the data acquisition and evaluation with the various sensors (temperatures, pressures, levels, etc.) follows in step S110. Then, in step S120, for example, the pressure, temperature, and level values at the last engine shutdown become 28 read from a memory and compared with the current measured values, checked for plausibility and possibly generates an error message.

In step S130, it is then checked whether a cold start of the internal combustion engine 28 is present. This can be done, for example, based on the measured cooling water temperature, which is below a threshold temperature of, for example, 35 ° C at a cold start. There is no cold start of the internal combustion engine 28 before, the leak test is aborted. In other words, the leakage test of the tank system according to the invention is preferably only after a cold start of the internal combustion engine 28 executed.

In Step S140 checks if all necessary components (Valves, pressure sensors, temperature sensors, level sensors, etc.) are present or correctly connected.

Prior to the leak tests in one or more subsystems of the tank system, in step S150, first the functional capabilities of the individual components of the tank system such as valves, pressure sensors, temperature sensors, level sensors, etc. are checked to ensure that the subsequent leak tests are correct and can be done with the right result. In particular, the functionalities of the regeneration valve 50 , one the tank 10 associated level sensor (not shown), the first and the second Tankabsperrventils 38 . 42 , the first and the second pressure sensor 60 . 62 and one the tank 10 associated temperature sensor (not shown) to be checked.

Then, in step S160, it is preferably checked in advance whether the gas cap 16 at the filler neck 14 of the tank 10 is closed, ie in particular currently no refueling is performed; and if the gas cap 16 is tight.

The Test operations in steps S130, S140, S150 and S160 itself are not the subject of the present invention. The proposed according to the invention leak test Rather, you can use arbitrary methods and methods for these steps are performed.

Now In step S170, the leak check follows in at least one Subspace of the tank system, d. H. in the first subspace, in the second subspace and / or in the third subspace according to their above definitions. Is at This leak check found that the tested subspace is dense ("J" in step S180), the flow goes proceed to step S190 of data acquisition and storage before the routine is ended in step S200.

following will exemplify the leak tests in the various Partial spaces of the tank system in step S170 closer described.

In a leak test of the first subspace, the first and second Tankabsperrventil 38 . 42 opened and the regeneration valve 50 and the two ventilation valves 54 . 58 closed. Then, by means of the first and / or the second pressure sensor 60 . 62 the pressure in the first compartment of the tank system are detected.

In a leak test of the second subspace, the first and second Tankabsperrventil 38 . 42 closed. Then, by means of the first pressure sensor 60 the pressure in the second compartment of the tank system can be detected.

In a leak test of the third subspace, the first and second Tankabsperrventil 38 . 42 , the regeneration valve 50 and the two ventilation valves 54 . 58 closed. Then, by means of the second pressure sensor 62 the pressure in the third compartment of the tank system can be detected.

The control device 64 determines, for example, a leak when it turns out in these leak tests that the pressure detected in the respective subspace deviates too much from the set during the last operation of the engine in this subspace pressure, ie, for example, a pressure equalization between the subspace and the atmosphere has taken place , Likewise, the control device 64 to close a leakage in the tank system, if the pressure detected in the respective subspace changes too much within a certain period of time.

In 3 and 4 further examples of a tank system with tank ventilation are shown, in which the above-described method for leak testing of the tank system can also be applied. In each case, the same or corresponding components of the tank system with the same reference numerals as in the above first example of 1 characterized.

The second example is different from the one in 1 illustrated tank system in that the main vent line 30 is omitted. The first vent line 32 to the first memory 36 and the second vent line 34 to the second memory 40 each stand directly with the interior of the tank 10 in connection. The other features of this tank system correspond to those of the above first example.

This in 4 Example illustrated differs from that in 1 illustrated tank system in that the first and the second Spülzweigleitung 44 . 46 from the two stores 36 . 40 separate from each other with the intake tract 26 the internal combustion engine 28 are connected. In addition, instead of a regeneration valve 50 in the rinse main 48 a first regeneration valve 50a in the first purge line 44 and a second regeneration valve 50b in the second purge line 46 intended. The first and the second regeneration valve 50a . 50b together form the regeneration valve in the context of the invention.

In this embodiment of the tank system, two separate third subspaces can be defined, each one of the two memory 36 . 40 assigned.

The second pressure sensor 62 In this case, for example, both flush lines 44 and 46 be assigned. Alternatively, there are two second pressure sensors 62 for each one of the two flushing lines 44 . 46 intended.

The remaining Features of this tank system correspond to those of the above first Example.

As a fourth example of the tank system, the two variants of 3 and 4 also be combined with each other.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 5111795 [0003, 0003]
• - DE 10101257 A1 [0006]
• DE 10204132 A1 [0007]
• - DE 10360337 A1 [0007]

Claims (12)

Method of leak testing a tank system, wherein the tank system comprises a tank ( 10 ) for receiving a fuel ( 12 ) for an internal combustion engine ( 28 ), a first memory ( 36 ) with a storage medium for at least temporarily binding of evaporative emissions, a first storage ( 36 ) with the tank ( 10 ) connecting first tank vent line ( 30 . 32 ), a first memory ( 36 ) with an intake tract ( 26 ) of the internal combustion engine ( 28 ) connecting first purge line ( 44 . 48 ), a second memory ( 40 ) with a storage medium for at least temporarily binding refueling emissions, a second storage ( 40 ) with the tank ( 10 ) connecting second tank vent line ( 30 . 34 ), a second memory ( 40 ) with the intake tract ( 26 ) of the internal combustion engine ( 28 ) connecting second purge line ( 46 . 48 ) and one in the first purge line ( 44 . 48 ) and / or the second purge line ( 46 . 48 ) arranged regeneration valve ( 50 ; 50a . 50b ), characterized in that in the first tank vent line ( 30 . 32 ) a first tank shut-off valve ( 38 ) and in the second tank vent line ( 30 . 34 ) a second tank shut-off valve ( 42 ) is arranged; during operation of the internal combustion engine ( 28 ) through the first tank shut-off valve ( 38 ), the second tank shut-off valve ( 42 ) and the regeneration valve ( 50 ; 50a . 50b ) a certain pressure is set in at least one subspace of the tank system; after a start of operation of the internal combustion engine, a pressure in the at least one subspace of the tank system is detected; and a leak test based on a comparison of the detected pressure in the at least one subspace of the tank system with the during the previous operation of the internal combustion engine ( 28 ) pressure and / or a change over time of the detected pressure in the at least one subspace of the tank system is performed. A method according to claim 1, characterized in that the leak test in the at least one subspace of the tank system after a cold start of the internal combustion engine ( 28 ) is carried out. A method according to claim 1 or 2, characterized in that the at least one subspace of the tank system includes a first subspace, the tank ( 10 ), the first and the second tank vent line ( 30 . 32 . 34 ) and the first and the second memory ( 36 . 40 ); and the leak test in the first subspace with closed regeneration valve ( 50 ; 50a . 50b ) and with the first and second tank shut-off valves open ( 38 . 42 ) is carried out. A method according to claim 3, characterized in that the pressure in the first subspace by means of a first pressure sensor ( 60 ) detected on the tank ( 10 ), the first tank vent line ( 30 . 32 ) and / or the second tank vent line ( 30 . 34 ) is arranged. A method according to claim 3 or 4, characterized in that the pressure in the first subspace by means of a second pressure sensor ( 62 ) detected at the first memory ( 36 ), the second memory ( 40 ), the first purge line ( 44 ) and / or the second purge line ( 46 ) is arranged. Method according to one of the preceding claims, characterized in that the at least one subspace of the tank system contains a second subspace which holds the tank ( 10 ) and the first and the second tank vent line ( 30 . 32 . 34 ) between the tank ( 10 ) and first or second Tankabsperrventil ( 38 . 42 ); and the leak test in the second subspace with closed first and second Tankabsperrventil ( 38 . 42 ) is carried out. A method according to claim 6, characterized in that the pressure in the second subspace by means of a first pressure sensor ( 60 ) detected on the tank ( 10 ), the first tank vent line ( 30 . 32 ) and / or the second tank vent line ( 30 . 34 ) is arranged. Method according to one of the preceding claims, characterized in that the at least one subspace of the tank system includes a third subspace containing the first and the second memory ( 36 . 40 ) and the first and the second tank vent line ( 32 . 34 ) between the respective memory ( 36 . 40 ) and the first and second Tankabsperrventil ( 38 . 42 ); and the leak test in the second subspace with closed first and second Tankabsperrventil ( 38 . 42 ) and with a closed regeneration valve ( 50 ; 50a . 50b ) is carried out. A method according to claim 8, characterized in that the pressure in the third subspace by means of a second pressure sensor ( 62 ) detected at the first memory ( 36 ), the second memory ( 40 ), the first purge line ( 44 ) and / or the second purge line ( 46 ) is arranged. Method according to one of the preceding claims, characterized in that the leak test in the at least one subspace of the tank system after a test of the operability (s) of the first Tankabsperrventils ( 38 ), the second Tankabsperrventils ( 42 ), the Regenerierven tils ( 50 ; 50a . 50b ), the first pressure sensor ( 60 ) and / or the second pressure sensor ( 62 ) is carried out. Method according to one of the preceding claims, characterized in that the leak test in the at least one subspace of the tank system only with a closed tank lid ( 16 ) of the tank ( 10 ) is carried out. Method according to one of the preceding claims, characterized in that the leak test in the at least one subspace of the tank system after a leak test of a tank cap ( 16 ) and / or a filler neck ( 14 ) of the tank ( 10 ) is carried out.

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