DE102018219189B3 - Device and method for operating an internal combustion engine using fuel and a water-fuel emulsion - Google Patents

Abstract

The invention is characterized by a device and a method for operating an internal combustion engine, which can be operated either with fuel or with a water-fuel emulsion, with a fuel tank (10) for storing fuel, a water tank (25) for storing water, one Mixing device (20) which is supplied with the fuel and the water to form a water-fuel emulsion, a high-pressure fuel reservoir (60) with a storage space (614) for storing the fuel and the water-fuel emulsion, a high-pressure fuel pump (40 ), which conveys the water-fuel emulsion to the high-pressure fuel reservoir (60) when the internal combustion engine is to be operated with a water-fuel emulsion. According to the invention, the high-pressure fuel reservoir (60) has a sound generating device (80), which introduces sound waves into the storage space (614) for the water-fuel emulsion of the high-pressure fuel reservoir (60).

Description

The present invention relates to an apparatus and a method for operating an internal combustion engine which operates with fuel and with a water-fuel emulsion, the fuel and the water-fuel emulsion being injected directly into combustion chambers of the internal combustion engine

Modern motor vehicles have internal combustion engines with direct fuel injection, in which the fuel is injected under high pressure, for example at 200 to 300 bar in a gasoline internal combustion engine, directly into the combustion chambers or in multi-cylinder internal combustion engines. Direct fuel injection requires a fuel supply device that provides pressurized fuel in every operating situation. Essential elements of this fuel supply device are the high-pressure pump, which conveys the fuel to the necessary pressure level, and a pressure accumulator (rail), in which the fuel is stored under high pressure and from which the injection valves are supplied with fuel.

Pressure accumulators of this type are used above all in the case of injection systems combined under the name “common rail”, which make it possible to keep the injection pressure independent of the speed of the internal combustion engine and the injection quantity.

A great advantage over low-pressure intake manifold injection of the fuel is that the fuel injected directly into the combustion chamber cools the combustion chamber there through its evaporation (enthalpy of vaporization). This effect is necessary in particular when the internal combustion engine is under high loads in order to limit the exhaust gas temperature in order, inter alia, to avoid damage to components arranged in the exhaust line of the internal combustion engine, in particular the exhaust gas catalytic converter or the exhaust gas turbocharger.

At full load, an additional mass of fuel is injected, thus enriching the combustion mixture. This is only for cooling and is not necessary for the torque-generating combustion. Such an enrichment increases the fuel consumption of the internal combustion engine, which is contrary to the legal requirement for resource conservation and a reduction in CO2 emissions.

Water injection is a long-known method for increasing performance, for reducing CO ₂ , as a replacement or at least for reducing the above-mentioned mixture enrichment at the full load of an internal combustion engine, for reducing the tendency to knock and for combating pre-ignition. In this process, the enthalpy of vaporization, which is six times higher than that of gasoline, is used when the water changes phases. Various systems are known with which the water can be fed to the combustion process.

In addition to the possibility of introducing the water into the air intake system of the internal combustion engine by means of a water injector, preferably immediately before the inlet valve, the DE 10 2011 015 628 A1 an operating method for a gasoline engine working with direct fuel injection is known, in which water is injected directly into the combustion chambers.

In the DE 10 2015 214 050 A1 A device for mixing fuel and water is described, which comprises the following: a pump, a pressure chamber, which comprises a fuel area and a mixing area, which are directly connected to one another, an intake valve, via which fuel can be drawn into the fuel area, and a water injection valve , via which water can be injected into the mixing area in order to mix water and fuel into a mixture. The mixture produced is fed to a high-pressure accumulator and injected into the internal combustion engine by means of injectors.

In the high-pressure injection systems, there is therefore also water in the high-pressure area, in particular in the high-pressure fuel reservoir. However, this water only forms an emulsion with the fuel for a finite time (approx. 20 seconds to a few minutes), and segregates again after this time. If the injection is now switched off during an emulsion injection phase, which is normally always done in overrun mode or in vehicles with hybrid drive when the internal combustion engine is switched off completely, there are two separate phases, namely water and fuel in the high-pressure fuel accumulator. The fuel floats on the water.

In this context, the term “emulsion injection phase” is to be understood as a period in which an emulsion of water and fuel is injected instead of pure fuel.

If the injection is switched on again, only water and no fuel is injected instead of a water-fuel emulsion, so that no combustion can take place and the internal combustion engine generates no torque.

This problem does not only exist when the injection is switched off completely, but also when switching from the emulsion injection phase to a lower load under high load of the internal combustion engine. For example, when changing from full load (when driving fast on the motorway or uphill) to idling over a short overrun phase with a low injection quantity, not all of the water-fuel emulsion filling is taken from the high-pressure fuel reservoir. The part of the water-fuel emulsion remaining in the high-pressure fuel reservoir has enough time to at least partially separate. Sporadic, individual or briefly completely pure water injections are the result, which considerably disturbs the smooth running of the internal combustion engine.

Due to the segregation in fuel and water, there is also the risk that if the internal combustion engine is switched off and the injection system is not activated, the water remaining in the high pressure area may form ice at a correspondingly low ambient temperature below 0 ° C. The expansion during the phase transition can lead to damage or destruction of components in the high-pressure region, or blockages of the high-pressure injection system occur when the internal combustion engine is restarted.

In order to avoid this, an attempt is made to convey the water-fuel emulsion through the high-pressure fuel reservoir as quickly as possible in order to keep the duration of the water-fuel emulsion in the high-pressure fuel reservoir as short as possible. However, if the retention time is longer than the stability time of the water-fuel emulsion, the two components separate.

In the DE 10 2011 076 670 A1 describes a fuel injection system for fuel, which has a low-pressure system with a tank and a low-pressure pump, as well as a water storage device and a device for admixing water to the fuel. It is provided in the fuel injection system with a device for admixing water to the fuel, with which a stable fuel-water emulsion can be generated. This is achieved in that the device is an ultrasound device and in that the ultrasound device interacts with a mixing chamber integrated in the fuel injection system. The fuel pump in this system only delivers fuel to the high-pressure accumulator.

The invention is based on the object of specifying a device and a method for operating an internal combustion engine which operates with fuel and with a water-fuel emulsion and which enables the internal combustion engine to be operated effectively and safely.

This object is achieved by a device according to claim 1 and by a method according to claim 10. Advantageous embodiments of the invention are the subject of the dependent claims.

The invention is characterized by a device and a method for operating an internal combustion engine, which can be operated either with fuel or with a water-fuel emulsion, with a fuel tank for storing fuel, a water tank for storing water, a mixing device which the fuel and the Water is supplied to form a water-fuel emulsion, a high-pressure fuel reservoir with a storage space for storing the fuel and the water-fuel emulsion, a high-pressure fuel pump which delivers the water-fuel emulsion to the high-pressure fuel reservoir when the internal combustion engine to be operated with a water-fuel emulsion. According to the invention, the high-pressure fuel reservoir has a sound generating device which introduces sound waves into the storage space for the water-fuel emulsion of the high-pressure fuel reservoir.

By introducing sound waves of high frequency, in particular by coupling ultrasonic waves, the segregation of the water-fuel emulsion can be effectively prevented without the flow behavior of the water-fuel emulsion being impaired. Since no segregation takes place, pure water cannot be accidentally injected, nor can water residues lead to ice formation, which can lead to blockage of the rail outlets on the high-pressure fuel accumulator or on the injectors connected to it. Due to the stabilization of the water-fuel emulsion by means of the sound waves, it remains fluid even at low temperatures.

According to a development of the invention, the high-pressure fuel reservoir is designed as a tubular base body with an axial bore, which forms a storage space for storing fuel or a water-fuel emulsion, and with an inlet connection for the fuel or the water-fuel having an inlet channel -Emulsion provided with drain ports provided according to the number of cylinders of the internal combustion engine, which in fluid connection with the individual cylinders assigned high pressure Stand fuel injectors, and the sound generating device on an end face of the tubular base body ( 601 ) arranged.
This results in a particularly simple arrangement of the sound generating device on the high-pressure fuel reservoir and a very effective introduction of the sound waves into the storage space for the water-fuel emulsion.

A particularly good stabilization of the water-fuel emulsion results when a part of the storage space is filled with a filler, so that overall a smaller storage space is formed for the water-fuel emulsion, so that a stable water-fuel is maintained -Emulsion has to be used less energy for the sound generating device due to the smaller amount.

Further refinements of the invention and advantages resulting therefrom result from the following description of preferred exemplary embodiments, which are shown in the drawing.

• 1 in schematischer Darstellung ein Kraftstoffzufuhrsystem für eine Verbrennungskraftmaschine mit einem Kraftstoff-Hochdruckspeicher gemäß einem ersten Ausführungsbeispiel,
• 2 eine vereinfachte Darstellung eines Kraftstoff-Hochdruckspeichers eines solchen Kraftstoffzufuhrsystems gemäß einem zweiten Ausführungsbeispiel und
• 3 eine vereinfachte Darstellung eines Kraftstoff-Hochdruckspeichers eines solchen Kraftstoffzufuhrsystems gemäß einem dritten Ausführungsbeispiel.

Show it:

• 1 a schematic representation of a fuel supply system for an internal combustion engine with a high-pressure fuel reservoir according to a first embodiment,
• 2nd a simplified representation of a high-pressure fuel reservoir of such a fuel supply system according to a second embodiment and
• 3rd a simplified representation of a high-pressure fuel reservoir of such a fuel supply system according to a third embodiment.

The 1 shows a schematic representation of a fuel supply system for an internal combustion engine, which can be operated either with direct injection of fuel or direct injection of a water-fuel emulsion, only the components necessary for understanding the invention are shown. In particular, filters, inlet and outlet valves, various pressure control valves, pressure sensors and return lines of the fuel circuit are omitted.

The one in a fuel tank 10th Stocked fuel, usually a gasoline (gasoline) or a diesel fuel, is powered by an electrically powered low pressure fuel pump 15 to a mixing device 20th promoted. This low pressure fuel pump 15 can also be inside the fuel tank 10th be arranged. There is also a water reservoir 25th provided from which by means of an electrically driven water pump 30th Water of the mixing device 20th is fed. The mixing device 20th is used to form a water-fuel emulsion and can work according to any known principle. If the internal combustion engine is to be operated exclusively with fuel, the water can flow from the water reservoir 25th to the mixing device 20th by means of an electrically switchable shut-off valve 35 or when using a leak-free water pump 30th simply by switching off the water pump 30th to be interrupted.

Water in the water reservoir 25th can either by the driver of the motor vehicle using a filler neck 26 can be refilled manually, or the water can be obtained onboard. In particular, the condensation water from the air conditioning system, treated rain water or the condensation water from the exhaust gas can be considered as water sources, the quality of the water being monitored in these cases. The water storage container has points for introducing such water obtained onboard 25th a feed port 27 on.

In or on the water reservoir 25th In addition to a sensor for the quality of the water, which can also detect incorrect refueling, a fill level sensor and a temperature sensor can be provided, the signal of which is in or on the water reservoir 25th arranged electric heating device activated at temperatures near the freezing point of the water. This ensures that liquid water is available at all times to form the emulsion.

The fuel or that in the mixing device 20th Water-fuel emulsion produced is by means of a high-pressure fuel pump, preferably mechanically driven by the internal combustion engine 40 via a high pressure line 45 transported to a high-pressure fuel reservoir (common rail) 60. This is used to store and dispense both high-pressure fuel and high-pressure water-fuel emulsions of different concentrations.

As an alternative to the separate mixing device 20th in the low-pressure circuit, the water-fuel emulsion can also be found in the high-pressure fuel pump 40 be generated. For the invention, the location and the manner in which the water-fuel emulsion is formed are only of importance insofar as the water-fuel emulsion is before it enters the high-pressure fuel reservoir 60 must be available.

The high-pressure fuel accumulator 60 is in the 1 shown in longitudinal section. It is suitable for supplying and / or storing both fuel and water-fuel Emulsions of different concentrations. In this context, both petrol and diesel are to be mentioned as fuel. The high-pressure fuel accumulator 60 is an elongated hollow body, preferably a tubular base body 601 designed with a cavity that delimits an internal volume and thus a storage space 614 of the fuel high-pressure accumulator 60 forms and which is filled with fuel or with the water-fuel emulsion during operation of the internal combustion engine. The basic body 601 is preferably made of metal, especially high-strength steel. On the main body 601 is a, radially from part of the outer wall of the base body 601 protruding inlet connection 602 for that from the high pressure fuel pump 40 coming high pressure line 45 provided so that one, in the inlet connection 602 provided inlet channel 603 a fluid connection to the storage space 614 of the fuel high-pressure accumulator 60 is made. Furthermore, are on the circumference of the main body 601 four drain connections 604 provided, which are also referred to as rail exits and to which lines, not shown, are connected, which lead to the individual high-pressure fuel injectors. In each of the drain connections 604 is a drain channel 605 provided so that a fluid connection from the storage space 614 of the fuel high-pressure accumulator 60 to the high pressure fuel injectors.

The distances between these drain connections are preferred 604 with each other, based on the longitudinal axis of the base body 601 , equidistant. If the individual drain connections 604 are relatively far apart and the installation space of the internal combustion engine allows it, the high-pressure fuel injectors can also be connected directly to the drain connections 604 to be assembled.

In the 1 are four such drain connections 604 shown what this fuel high-pressure accumulator 60 is designed for a 4-cylinder internal combustion engine. However, it should be noted that the fuel high-pressure accumulator 60 is also suitable for internal combustion engines with any number of cylinders, in which case a number of drain connections corresponding to the number of cylinders 604 are provided.

To prevent the water-fuel emulsion from segregating when the water-fuel emulsion is in the high-pressure accumulator for longer periods 60 counteracting is on the high pressure accumulator 60 according to the invention a sound generating device 80 , preferably an ultrasound generating device is provided. For the generation of ultrasound, i.e. sound waves with a frequency above the human hearing range, i.e. from about 20 KHz to 1 GHz, transducers according to the reverse piezo effect are particularly suitable, for example a piezo speaker, i.e. membrane-coupled plates made of piezoceramic material, which are excited to vibrate. The vibrations are either direct or as in the 1 shown, by means of a coupling element 85 into the storage space filled with the water-fuel emulsion 614 of the fuel high-pressure accumulator 60 fed. Due to the high-frequency pressure waves of high intensity that in the pressure accumulator 60 Existing water-fuel emulsion is kept stable and there is no separation of the two components, even if the water-fuel emulsion remains in the high-pressure fuel reservoir for a long time 60 .

An electronic control device is used to control and regulate the internal combustion engine 50 provided, which also includes switching from fuel injection to the injection of the water-fuel emulsion, the control of the low-fuel pressure pump 15 , the water pump 30th , the shut-off valve 35 , and the sound generating device 80 takes over. The water-fuel emulsion is injected in particular at very high loads of the internal combustion engine in order to reduce the high temperatures that occur or for knock control. By closing the shut-off valve 35 or switch off the water pump 30th by means of signals from the control device 50 the generation of the water-fuel emulsion is stopped.

The control device is connected via interfaces 50 including signals IT supplied by a wide variety of sensors on the input side and from them it generates control signals or output signals AS for a wide variety of actuators, such as high-pressure fuel injectors. Such control devices 50 , which generally contain one or more microprocessors, are known per se, so that they are not discussed in more detail below.
In the 2nd is another embodiment of a high pressure fuel accumulator 60 shown which differs from that based on the 1 described embodiment differs in that the storage space 614 of the basic body 601 such with a, preferably cylindrical filler 606 is filled in so that in relation to the entire storage space 614 of the basic body 601 a greatly reduced storage space for the fuel or the water-fuel emulsion only a few channels in the form of grooves remain. In detail, these are about the circumference of the packing 606 introduced ring grooves 607 which in relation to the longitudinal extent of the base body 601 are arranged so that they with the drainage channels 605 the drain connections 604 aligned and thus fluid connections between the ring grooves 607 and the drainage channels 605 produce.

On the circumference of the packing 606 is another ring groove 608 provided which in relation to the longitudinal extent of the base body 601 is introduced in such a way that it is connected to the inlet channel 603 the inlet connection 602 aligned and thus a fluid connection between the inlet channel 603 and the ring groove 608 manufactures. So that fuel or the water-fuel emulsion from the inlet channel 603 into the drainage channels 605 can reach is on the surface of the packing 606 at least one further channel in the form of a longitudinal groove 609 provided which the individual ring grooves 607 , 608 connects with each other.

The prefabricated packing 606 with its channels is through an open face of the body 601 in the storage room 614 (Cavity) of the base body 601 inserted and then the base body 601 on this front side by means of a closure part 610 sealed pressure-tight, for example welded.

As materials for the packing 606 solids come into question, the compression modulus of which is similar to the compression modulus of the fuel, namely approximately 10000 bar. PTFE plastics (polytetrafluoroethylene), which have an elastic modulus E = of approx. 5000 bar, are particularly suitable, which corresponds to a compression modulus of approx. 8333 bar according to equation K = E / 3 (1-2 * µ) (calculated with a for plastic the usual Poisson number µ of approx. 0.4).

The packing 606 can, for example, 20% of the storage space 614 up to 99% of the storage space 614 to complete. The fuel-carrying or the emulsion-carrying ring grooves can 607 , 608 and the at least one longitudinal groove 609 in the same order of magnitude as the inlet channel 603 and the drainage channels 605 be, for example, have a diameter in the range of approximately 1 mm to 9 mm. On the one hand, the grooves mentioned represent the fuel or emulsion storage space when the high-pressure fuel injectors are closed and, on the other hand, they enable the fluid flow from the inlet connection when the high-pressure fuel injectors are open 602 to the drain connections 604 of the fuel high-pressure accumulator 60 for sure.

The introduction of sound into the fluid-carrying storage space 614 which in this case comes from the ring grooves 607 and the longitudinal groove 609 is formed, takes place with a coupling element 85 on the one hand with the sound generating device 80 and on the other hand with the longitudinal groove 609 communicates. Because the longitudinal groove 609 as described at the beginning, again with the individual ring grooves 607 communicates, the sound waves can cover the whole, in the storage space 614 water-fuel emulsion.

In the 3rd is another embodiment of a high pressure fuel accumulator 60 shown according to the invention. The inner volume of the body 601 is also with a packing 606 lined. However, it differs from the arrangement according to the 2nd by not having grooves in the packing 606 the storage and management of the fuel or the water-fuel emulsion take over, but in the packing 606 is an axially extending pipe 611 (rail) embedded, which on the one hand by means of a branch line 613 with the inlet channel 603 the inlet connection 602 and by means of branch lines 612 with the drainage channels 605 the drain connections 604 communicate.
The storage space 614 of the basic body 601 is such with a, preferably cylindrical packing 606 filled in so that in relation to the entire inner volume of the base body 601 a greatly reduced storage space 614 for the fuel or the water-fuel emulsion. As materials for the packing 606 solids come into question, the compression modulus of which is similar to the compression modulus of the fuel, for example PTFE plastics (polytetrafluoroethylene).

The lines mentioned 611 , 612 , 613 represent the fuel or emulsion storage space when the high-pressure fuel injectors are closed and, on the other hand, enable the fluid flow from the inlet connection when the high-pressure fuel injectors are open 602 to the drain connections 604 of the high pressure accumulator 60 .

The packing 606 can after inserting the prefabricated pipeline 611 including their branch lines 612 , 613 over an open end face of the base body 601 in the storage room 614 of the basic body 601 in particular by overmolding the lines mentioned 611 , 612 , 613 be introduced. Then the main body 601 on this front side by means of a closure part 610 sealed pressure-tight, for example welded.

The hollow volumes for storing the fuel or water-fuel emulsion, formed from the pipeline 611 and the branch lines 612 , 613 can be about 70% to 99% of the inner volume of the body 601 be.

To even with such a high-pressure fuel accumulator 60 segregation of the water-fuel emulsion with longer dwell times of the water-fuel emulsion in the high-pressure accumulator 60 to counteract the vibrations by means of a coupling element 85 into the fluid-carrying pipeline 611 fed, from which they are also in the branch lines 612 and 613 reproduce. Due to the high-frequency pressure waves of high intensity in the fuel high-pressure accumulator 60 existing water-fuel emulsion is kept stable and there is no separation of the two components, even when the emulsion is in the high-pressure accumulator for a long time.

All of the exemplary embodiments have in common that the sound is introduced into the storage space or into the fluid-carrying grooves and lines within the high-pressure fuel accumulator 60 by means of the sound generating device 80 continuously during the emulsion injection phase of the internal combustion engine 5 can take place or only in a critical period in which segregation of the emulsion seems likely. This is the case, for example, if the internal combustion engine is switched off immediately after operation with the emulsion or during an operating phase of a hybrid vehicle with an electrical machine as the drive source.

The sound can also be introduced during a standstill phase with the system completely shut down, for example overnight. Part of the control device can do this 50 , which is usually integrated in an engine control unit, remain active and the sound generating device 80 supply with energy so that segregation of the emulsion is counteracted. Is a separate supply device for the sound generating device 80 provided, this can be activated actively overnight.

A sound can be introduced for re-emulsioning in order to integrate the already separated components back into the emulsion.
For example, before starting the journey in the morning after a long standstill phase of the internal combustion engine 5 and thus switched-off injection, initiated by opening the driver's door, the sound generator 80 be activated so that the segregation is canceled again when the internal combustion engine starts.

Reference list

10th

Fuel tank

15

Low pressure fuel pump

20th

Mixing device for emulsion formation

25th

Water reservoir

26

Filler neck

27

Feed connection

30th

water pump

35

Shut-off valve

40

High pressure fuel pump

45

High pressure line

50

electronic control device

60

High-pressure fuel accumulator (common rail)

601

Basic body

602

Inlet connection

603

Inlet channel

604

Drain connection

605

Drain channel

606

Packing

607

Ring groove

608

Ring groove

609

Longitudinal groove

610

Closure part

611

Pipeline

612

Branch line

613

Branch line

614

Storage space, cavity

80

Sound generating device

85

Coupling element

IT

Input signals

AS

Output signals

Claims (14)

Device for operating an internal combustion engine, which can be operated either with fuel or with a water-fuel emulsion, with - a fuel tank (10) for storing fuel, - a water tank (25) for storing water, - a mixing device (20) which supplies the fuel and the water is supplied to form a water-fuel emulsion, - a high-pressure fuel reservoir (60) with a storage space (614) for storing the fuel and the water-fuel emulsion, - a high-pressure fuel pump (40) which supplies the water -Fuel emulsion to the high-pressure fuel reservoir (60) promotes, if the internal combustion engine is to be operated with a water-fuel emulsion, characterized in that the high-pressure fuel reservoir (60) has a sound generator (80), which sound waves in the Storage space (614) for the water-fuel emulsion of the fuel high-pressure accumulator (60) brings. Device after Claim 1 , characterized in that the high-pressure fuel reservoir (60) is designed as a tubular base body (601) with an axial bore, which forms a storage space (614) for storing fuel or a water-fuel emulsion, - with one, one Inlet channel (603) having inlet connection (602) for the fuel or the water-fuel emulsion is provided, - is provided with outlet connections (604) provided according to the number of cylinders of the internal combustion engine, which outlet connections (604) are in fluid communication with the individual cylinders assigned high-pressure fuel injectors (70), - the sound generating device (80) is arranged on an end face of the tubular base body (601). Device after Claim 1 or 2nd , characterized in that - the storage space (614) is filled with a filler (606) such that a reduced storage space (614) is formed for the fuel or the water-fuel emulsion with respect to the entire storage volume (614) , - A solid body is used as the filler body (606), the compression module of which approximately corresponds to the compression module of the fuel used. Device after Claim 3 , characterized in that the reduced storage volume (614) is designed as channels in the form of grooves (607, 608, 609) in the packing (606) and the grooves (607, 608, 609) are in flow connection with one another. Device after Claim 4 , characterized in that - an annular groove (608) is provided on the circumference of the filler body (606), which is introduced at one point with respect to the longitudinal extent of the base body (601) such that it is flush with the inlet channel (603) and thus a flow connection produces between the inlet channel (603) and the annular groove (608), - further annular grooves (607) are provided on the circumference of the packing (606), which are introduced in places with respect to the longitudinal extent of the base body (601) so that they can be connected to the outlet channels ( 605) and thus establish a flow connection between the annular grooves (607) and the drainage channels (605), - at least one longitudinal groove (609) is provided on the surface of the packing (606) in the axial direction, said longitudinal groove (609) ) connects with each other and thus creates a flow connection between the inlet channel (603) and the outlet channels (605). Device after Claim 4 or 5 , characterized in that the cross sections of the annular grooves (607, 608) and the longitudinal groove (609) are identical to the cross sections of the inlet channel (603) and the outlet channels (605). Device after Claim 3 , characterized in that the reduced storage volume is formed by means of a pipeline (611) embedded in the filler (606) and extending in the axial direction of the main body (601), which on the one hand by means of a branch line (613) to the inlet channel (603) of the Inlet connection (602) and by means of branch lines (612) to communicate with the outlet channels (605) of the outlet connections (604). Device after Claim 3 , characterized in that the filler (606) occupies 20% to 99% of the storage space (614) and is a PTFE plastic. Device according to one of the preceding claims, characterized in that the sound waves are ultrasonic waves. Method for operating an internal combustion engine, which can be operated either with fuel or with a water-fuel emulsion, the internal combustion engine comprising: - a fuel tank (10) for storing fuel, - a water tank (25) for storing water, - a mixing device ( 20) to which the fuel and the water are supplied to form a water-fuel emulsion, - a high-pressure fuel reservoir (60) with a storage space (614) for storing the fuel and the water-fuel emulsion, - a high-pressure fuel pump (40 ), which promotes the water-fuel emulsion to the high-pressure fuel reservoir (60) when the internal combustion engine is to be operated with a water-fuel emulsion, characterized in that for stabilizing or re-emulsioning the water-fuel emulsion in the storage space (614) of the fuel high-pressure accumulator (60) sound waves by means of a sound generator ungseinrichtung (80) are introduced. Procedure according to Claim 10 , characterized in that the sound waves of the sound generating device (80) are introduced into the storage space (614) by means of a coupling element (85). Procedure according to Claim 10 or 11 , characterized in that the introduction of the sound waves continuously during the operation of the Internal combustion engine with the water-fuel emulsion. Procedure according to Claim 10 or 11 , characterized in that the introduction of the sound waves takes place in a critical period of possible segregation of the water-fuel emulsion. Procedure according to Claim 10 or 11 , characterized in that the introduction of the sound waves takes place during a standstill phase of the internal combustion engine.

Images