DE102022103532A1 - Method for operating an internal combustion engine and corresponding internal combustion engine - Google Patents

Abstract

The invention relates to a method for operating an internal combustion engine (1) for a motor vehicle, which has at least one cylinder with a combustion chamber and a spark plug (3), with an ignition point of the spark plug (3) outside the combustion chamber (2) in a Combustion chamber (2) fluidically connected antechamber (4) is arranged. It is provided that at least temporarily a scavenging mixture of fuel and fresh gas is generated by means of a mixture formation device (5) outside the combustion chamber (2) and the antechamber (4) and is introduced directly into the antechamber (4) for scavenging the antechamber (4).

Description

The invention relates to a method for operating an internal combustion engine for a motor vehicle, which has at least one cylinder having a combustion chamber and a spark plug, with an ignition point of the spark plug being arranged outside the combustion chamber in a prechamber fluidically connected to the combustion chamber.

From the prior art, for example, the publication DE 10 2020 133 434 A1 known. This describes methods and systems for operating a cylinder of an engine that includes a pre-chamber ignition system. In one example, a method may include determining amounts of pre-chamber gases in the cylinder prior to combustion and adjusting an amount of fuel injected into the cylinder based on the amounts of pre-chamber gases in the cylinder. In this way, cylinder fueling may compensate for additional air and/or fuel from the pre-chamber gases, which may increase cylinder fueling accuracy and cylinder efficiency.

It is the object of the invention to propose a method for operating an internal combustion engine which has advantages over known methods, in particular in connection with prechamber ignition which enables stable combustion.

According to the invention, this is achieved with a method for operating an internal combustion engine for a motor vehicle with the features of claim 1 . It is provided that at least temporarily a scavenging mixture of fuel and fresh gas is generated by means of a mixture formation device outside the combustion chamber and the antechamber and is introduced directly into the antechamber for scavenging the antechamber.

Advantageous configurations with expedient developments of the invention are specified in the dependent claims.

The internal combustion engine is used, for example, to drive the motor vehicle and to that extent to provide a drive torque aimed at driving the motor vehicle. It is preferably part of the motor vehicle, but can of course also be present separately from it. The internal combustion engine has the cylinder in which a piston is displaceably arranged. The piston encloses the combustion chamber with a cylinder wall of the cylinder and a cylinder roof or cylinder head. The cylinder wall is preferably part of a cylinder crankcase or is formed by the cylinder crankcase.

The internal combustion engine has a fresh gas tract via which fresh gas is supplied to the internal combustion engine at least at times. The fresh gas preferably contains fresh air which is taken from an area outside the internal combustion engine. At least one gas exchange valve is fluidically connected to the combustion chamber. In terms of flow, the gas exchange valve is located between the fresh gas tract and the combustion chamber, with a flow connection being established between the fresh gas tract and the internal combustion engine when the gas exchange valve is at least partially open and interrupted when the gas exchange valve is closed. The gas exchange valve is preferably arranged and/or formed on or in the cylinder head.

During operation of the internal combustion engine, a mixture of fuel and fresh gas present in the combustion chamber is burned at least temporarily. Due to its presence in the combustion chamber, the mixture is also referred to as the combustion chamber mixture. To burn the combustion chamber mixture, it is ignited by the spark plug. However, the ignition point of the spark plug is not arranged inside the combustion chamber, but rather outside of the combustion chamber in the antechamber. The antechamber is fluidically connected to the combustion chamber via at least one through-opening, preferably exclusively via the at least one through-opening.

There are preferably a plurality of passage openings, via which the antechamber is fluidly connected to the combustion chamber. If the through-opening or the at least one through-opening is mentioned within the scope of this description, then the explanations are preferably applicable to each of the several through-openings, if these are present. For example, the spark plug is a prechamber spark plug, so that the prechamber is part of the spark plug. However, the antechamber can also be formed separately from the spark plug, in particular on the cylinder head, with the spark plug, for example a hook spark plug, protruding into the antechamber in the usual way.

To ignite the combustion chamber mixture, a mixture of fuel and fresh gas in the prechamber is first ignited by means of the spark plug. This mixture is also referred to as the pre-chamber mixture. The ignition of the pre-chamber mixture causes a jet of flame that enters the combustion chamber through the at least one through-opening and spreads out there tet. The jet of flame causes the combustion chamber mixture present in the combustion chamber to ignite. The combustion chamber mixture is therefore not ignited directly by means of the spark plug, but only indirectly by igniting the prechamber mixture.

The pre-chamber mixture used for ignition is formed by introducing fuel and fresh gas into the pre-chamber. The pre-chamber mixture is formed, for example, from the combustion chamber mixture, in particular introduced into the pre-chamber via the at least one through-opening by a stroke movement of the piston. Additionally or alternatively, fuel and fresh gas are introduced directly into the antechamber. In such a procedure, in particular, the prechamber mixture can have a composition that differs from a composition of the combustion chamber mixture. The pre-chamber mixture particularly preferably has a larger proportion of fuel than the combustion chamber mixture, so that the pre-chamber mixture has a richer composition than the combustion chamber mixture.

The composition of the pre-chamber mixture is influenced by combustion gases that have remained in the combustion chamber and/or the pre-chamber, for example from combustion during a previous working cycle of the cylinder. In addition to the fuel and the fresh gas, the pre-chamber mixture can therefore contain the combustion gases which at least impair or even completely suppress ignition of the pre-chamber mixture. This can be the case, in particular, during operation of the internal combustion engine at part load, so that reliable ignition of the combustion chamber mixture by means of ignition of the prechamber mixture is at least temporarily not ensured.

In order to enable reliable ignition and stable combustion of the combustion chamber mixture, provision can be made to provide a further spark plug in addition to the spark plug, the ignition point of which is arranged in the combustion chamber. If direct ignition of the combustion chamber mixture by means of the spark plug is not reliably possible, the additional spark plug can be used to ignite the combustion chamber mixture directly in the combustion chamber. However, this is associated with corresponding installation space requirements and additional costs for the additional spark plug.

The invention therefore provides for the antechamber to be flushed at least temporarily by introducing the flushing mixture into the antechamber. The scavenging mixture of fuel and fresh gas is generated outside the combustion chamber and the pre-chamber and introduced directly into the pre-chamber. This means that the scavenging mixture is not introduced from the combustion chamber into the antechamber via the passage opening, rather the scavenging mixture is introduced directly into the antechamber, bypassing the combustion chamber in terms of flow. The flushing mixture introduced into the antechamber forms the antechamber mixture there or represents at least part of it.

The flushing mixture is generated by means of the mixture formation device. The scavenging mixture is thus not first formed in the antechamber, rather it is already formed in the mixture-forming device from the fuel and the fresh gas and is made available for scavenging the antechamber. For this purpose, fuel and fresh gas are supplied to the mixture formation device. For example, the composition of the flushing mixture generated by means of the mixture-forming device is constant over time, in particular it cannot be changed. However, the composition of the flushing mixture can preferably be adjusted. In particular, the proportion of fuel in the scavenging mixture can be adjusted, and this can also be zero, so that the antechamber is only scavenged with fresh gas. The flushing mixture generated by means of the mixture-forming device is preferably introduced into the antechamber in an unchanged form, in particular in a chemically unchanged form.

For example, the composition of the scavenging mixture is constant during operation of the internal combustion engine, so that the mixture-forming device provides a scavenging mixture with a composition that is constant during operation. The composition of the scavenging mixture particularly preferably deviates from a stoichiometric mixing ratio of fuel and fresh gas. The scavenging mixture preferably has excess air, so that a lean combustion air ratio is set and a lean prechamber mixture is present in the prechamber after scavenging.

In order to introduce the flushing mixture into the antechamber, the mixture-forming device is fluidically connected to the antechamber at least at times, preferably via at least one valve device. In other words, the mixture formation device is fluidically connected to the antechamber via the valve device, again bypassing the combustion chamber. In a first setting of the valve device, the flow connection between the mixture formation device and the antechamber is interrupted. In a second setting, however, it is made so that the flushing mixture from the mixture formation device in the direction of the front chamber flows, in particular flows into this. Since the scavenging mixture is introduced directly into the antechamber, bypassing the combustion chamber, combustion gases present in the antechamber are forced by the scavenging mixture through the at least one passage opening out of the antechamber and into the combustion chamber, thus scavenging the antechamber.

After rinsing the antechamber, the rinsing mixture is present in it, in this respect the rinsing mixture generated by the mixture-forming device after rinsing corresponds to the antechamber mixture or forms this at least partially or even completely.

For example, it can be provided that during a working cycle of the cylinder, the pre-chamber mixture is initially formed from the scavenging mixture provided by the mixture-forming device. The pre-chamber mixture used for the ignition can correspond to the scavenging mixture in this respect. However, the pre-chamber mixture used for the ignition is preferably only formed in the pre-chamber, namely from the scavenging mixture. For example, part of the combustion chamber mixture is introduced from the combustion chamber into the prechamber and forms the prechamber mixture there together with the scavenging mixture. Additionally or alternatively, fuel and/or fresh gas are introduced directly into the prechamber, so that the prechamber mixture is composed of the scavenging mixture and the additionally introduced fuel or fresh gas and—optionally—the combustion chamber mixture. This procedure achieves reliable ignition of the prechamber mixture and stable combustion of the combustion chamber mixture. In this way, in particular, the additional spark plug can be dispensed with. Furthermore, a reliable setting of the pre-chamber mixture used for the ignition is possible since combustion gases remaining in the pre-chamber are removed from it by the scavenging.

A development of the invention provides that the scavenging mixture is generated by swirling fuel in fresh gas in a mixing chamber of the mixture formation device. For supplying the fresh gas, the mixture formation device is preferably fluidically connected to the fresh gas tract of the internal combustion engine. The fresh gas is swirled with fuel in the mixing chamber, in particular the fuel is atomized in the fresh gas. For example, an aerosol of liquid fuel and fresh gas is formed in the mixing chamber. The procedure can be to use this aerosol as a flushing mixture and to introduce it into the antechamber. However, it can also be provided that the fuel contained in the aerosol is initially evaporated as part of the generation of the scavenging mixture, in particular only partially, at least partially or completely, and only subsequently introduced into the antechamber.

The mixing chamber is fluidically connected to the antechamber of the cylinder via the at least one valve device. The scavenging mixture is present in the mixing chamber under a mixing chamber pressure that is greater than a pressure present in the antechamber during scavenging. For flushing the antechamber, the valve device is at least temporarily in the second setting, so that a flow connection between the mixing chamber and the antechamber is released. The scavenging mixture subjected to the mixing chamber pressure is forced into the antechamber when the valve device is thus open. Away from the flushing, ie before and after the flushing, the valve device is in the first setting, so that in this respect the flow connection between the mixing chamber and the antechamber is interrupted. In particular, a conventional fuel injector can be used as the valve device. As a result, a structurally particularly simple and cost-effective implementation of the method is possible.

The internal combustion engine particularly preferably has multiple cylinders and correspondingly multiple antechambers, with the mixing chamber or the mixture-forming device being designed in the form of a common rail, via which the scavenging mixture is provided jointly for multiple, in particular all, cylinders of the internal combustion engine and correspondingly all the antechambers. For example, each antechamber is fluidically connected to the mixing chamber via at least one valve device. In this respect, the mixing chamber serves as a common mixing chamber for multiple cylinders of the internal combustion engine. This ensures that the scavenging mixture with an identical composition is available for all cylinders.

A further development of the invention provides that the fuel is conveyed by means of a propellant medium flowing through a propellant nozzle into the mixing chamber. The mixture formation device has a propellant medium inlet for supplying the propellant medium and a fuel inlet for supplying the fuel to be delivered. The motive medium is fed to the motive nozzle via the motive medium inlet and flows through it into the mixing chamber. The mixture formation device is connected, for example, to a fuel tank of the motor vehicle via the fuel inlet. The fuel supplied to the combustion chamber is preferably also taken from the fuel tank. Accordingly, the fuel tank is fluidically connected to the combustion chamber and via the mixture formation device to the antechamber. A gaseous fluid, for example pressurized fresh gas, is preferably used as the propellant medium. Alternatively, fuel can be used as the driving medium.

The motive nozzle has a motive nozzle channel through which the motive medium flows up to a motive medium outlet. The driving nozzle is connected to the mixing chamber at the driving medium outlet, so that the driving medium flows through the driving medium outlet into the mixing chamber. A flow cross-sectional area of the driving nozzle channel decreases in the direction of the mixing chamber. The propulsion nozzle is designed, for example, as a Venturi nozzle, the flow cross-sectional area of which decreases in the direction of flow down to a smallest flow cross-sectional area and then increases. In this respect, the propulsion nozzle channel is designed to be convergent-divergent.

The fuel inlet opens into the propulsion nozzle channel, preferably at or in an area of the smallest flow cross-sectional area. The narrowing of the motive nozzle channel creates a suction effect that draws in the fuel through the fuel inlet. The fuel is thus conveyed into the mixing chamber by the propellant medium. In the mixing chamber, the fuel is swirled with the fresh gas present in the mixing chamber and the scavenging mixture is produced. The scavenging mixture is present as a mixture of fuel, fresh gas and propellant. By conveying the fuel by means of the propellant medium, an electric and/or mechanical fuel pump can be dispensed with.

Alternatively, the propellant nozzle is designed as a jet nozzle, with the propellant medium forming a free jet when it flows into the mixing chamber. In this case, the propellant nozzle is designed to be convergent, so that the smallest flow cross-sectional area is present at the propellant medium outlet. In this case, the fuel inlet is preferably connected to the mixing chamber downstream of the driving nozzle, so that only the driving medium flows from the driving medium outlet into the mixing chamber. A suction effect arises in the mixing chamber, in particular as a result of an exchange of momentum and/or the Venturi effect, which sucks the fuel into the mixing chamber via the fuel inlet. The scavenging mixture is effectively mixed through the momentum exchange between the propellant medium and the fresh gas present in the mixing chamber.

A development of the invention provides that the fresh gas is used as the propellant medium. As explained above, the fuel is conveyed by means of the motive medium flowing through the motive nozzle into the mixing chamber. In addition to the fresh gas and the delivered fuel, the propellant medium is therefore present in the mixing chamber. The flushing mixture generated in the mixing chamber will thus at least partially contain the propellant.

It is now planned to use the fresh gas as a propellant. For this purpose, the fresh gas is supplied to the motive medium inlet so that it flows through the motive nozzle into the mixing chamber and delivers the fuel. The fuel is thus conveyed by means of the fresh gas used to generate the scavenging mixture. To generate the scavenging mixture, only the fuel and the fresh gas are supplied to the mixing chamber, with the fuel being conveyed by means of the fresh gas. This creates a mixture formation device that is structurally particularly simple in design.

A development of the invention provides that the fresh gas is conveyed in the direction of the mixing chamber by means of a compressor, in particular a compressor of an exhaust gas turbocharger or a compressor of the internal combustion engine. The compressor serves, for example, to increase performance and/or to increase the efficiency of the internal combustion engine. In the case of the exhaust gas turbocharger, the compressor is driven by means of a turbine through which an exhaust gas from the internal combustion engine flows. Additionally or alternatively, the compressor is part of the compressor, in which case it is driven by the internal combustion engine and/or by an electric machine.

The fresh gas conveyed by means of the compressor is preferably introduced into the combustion chamber at least temporarily and/or at least partially via an inlet channel. The fresh gas is thus used to form the combustion chamber mixture and is acted upon by the compressor with a boost pressure. Provision is now made to introduce part of the fresh gas delivered by means of the compressor into the combustion chamber via the inlet channel, while another part of the fresh gas is used to generate the scavenging mixture.

The fresh gas is particularly preferably fed to the propellant medium inlet of the mixture formation device with the charging pressure of the compressor. The fresh gas charged with the boost pressure thus flows into the mixing chamber via the motive nozzle channel. The mixing chamber pressure thus corresponds to the charging pressure of the compressor. By conveying the fresh gas using the Ver more densely, a separate conveying device for providing the fresh gas can be dispensed with. In addition, the mixing chamber pressure is maintained by the charging pressure of the compressor.

A development of the invention provides that a mixing chamber pressure present in the mixing chamber is measured by means of a pressure sensor and the flushing mixture is introduced into the antechamber over a period of time selected as a function of the measured mixing chamber pressure. As already explained above, the flushing mixture is present in the mixing chamber at the mixing chamber pressure, the mixing chamber being fluidically connected to the antechamber via the valve device. The introduction period describes the period of time during which the flushing mixture is introduced into the antechamber. The introduction period thus determines the quantity of the flushing mixture introduced into the antechamber.

For example, the valve device is at least partially opened over the duration of the introduction period. The valve device is preferably in an open position over the entire introduction period, corresponding to the second setting. Outside the introduction period, the valve device is in a closed position, corresponding to the first setting. In the open position, the flushing mixture subjected to the mixing chamber pressure is pushed into the antechamber. The amount of flushing mixture introduced into the antechamber is therefore dependent on the mixing chamber pressure and the duration of the introduction period.

The mixing chamber pressure is measured using the pressure sensor. The introduction time period required for introducing the specific quantity of the flushing mixture is set from the measured mixing chamber pressure. For example, immediately before the antechamber is flushed, a momentarily present mixing chamber pressure is measured and the introduction time period required for introducing the specific quantity is calculated from this. The valve device is then opened and closed after the introduction period has elapsed. This ensures that the antechamber is always flushed with the specified quantity of the flushing mixture.

A development of the invention provides that during a working cycle of the cylinder, a fluid is introduced directly into the antechamber in addition to the scavenging mixture. The flushing mixture is introduced directly into the antechamber to flush it. Provision is now made to additionally introduce the fluid into the antechamber, preferably immediately after the antechamber has been flushed. Particularly preferably, the antechamber is flushed during an intake stroke of the working cycle, while the fluid is introduced into the antechamber during a compression stroke of the same working cycle that follows the intake stroke.

The fluid is, for example, the combustion chamber mixture, which is at least partially forced through the passage openings into the antechamber by the stroke movement of the piston. Alternatively, the fluid is additionally introduced fresh gas and/or additionally introduced fuel. After the fluid has been introduced, the pre-chamber mixture is present in the pre-chamber and in this respect consists at least partially of the flushing mixture and the fluid. The additional introduction of the fluid can influence a composition of the pre-chamber mixture and optimal ignition and combustion of both the pre-chamber mixture and the combustion chamber mixture can be achieved.

A development of the invention provides that fresh gas or a further flushing mixture is used as the fluid, the further flushing mixture having the same composition as the flushing mixture or a composition different from the composition of the flushing mixture. As explained above, the pre-chamber mixture consists at least in part of the purge mixture and the fluid. The composition of the antechamber mixture is influenced by the introduction of the fluid.

If fresh gas is used as the fluid, the proportion of fresh gas in the composition of the prechamber mixture is increased. The prechamber mixture thus has a leaner composition than the composition of the scavenging mixture. This enables efficient combustion of the pre-chamber mixture, especially when using a rich combustion chamber mixture.

Alternatively, it can be provided that the further flushing mixture is used as the fluid. The further rinsing mixture can have the same composition as the rinsing mixture used for rinsing. For example, the composition of the scavenging mixture and the further scavenging mixture corresponds to a stoichiometric combustion air ratio. This ensures that the pre-chamber mixture has a composition required for stoichiometric combustion.

However, it can also be provided that the composition of the further rinsing mixture differs from the composition of the rinsing mixture. For example, that points to rinsing used scavenging mixture has a composition that corresponds to a lean combustion air ratio, while the composition of the other scavenging mixture corresponds to the stoichiometric combustion air ratio. This reduces fuel consumption during flushing.

A development of the invention provides that the fluid to be introduced into the antechamber is provided by means of the mixture-forming device or a further mixture-forming device present in addition to the mixture-forming device. As already explained above, the flushing mixture is generated in the mixing chamber of the mixture-forming device. In this respect, the mixture formation device provides the scavenging mixture for scavenging the antechamber. Provision can now be made to use the flushing mixture provided by the mixture-forming device as the fluid to be introduced into the antechamber. In this case, after the introduction of the rinsing mixture for rinsing the antechamber, the rinsing mixture is introduced again as the fluid.

Additionally or alternatively, the further mixture-forming device can be provided, which is present in addition to the mixture-forming device. The additional mixture-forming device is preferably constructed analogously to the mixture-forming device, so that reference is made to the above explanations. The additional mixture-forming device differs from the mixture-forming device in particular with regard to the propellant nozzle. The composition of the scavenging mixture generated in the mixing chamber is influenced by the configuration of the propellant nozzle, in particular when the fresh gas is used as the propellant medium for conveying the fuel. For example, the additional mixture-forming device is designed in such a way that it provides the additional flushing mixture as the fluid, the composition of which differs from the composition of the flushing mixture. This enables particularly flexible operation of the internal combustion engine.

The invention also relates to an internal combustion engine for a motor vehicle, in particular for carrying out the method according to the statements made within the scope of this description, the internal combustion engine having at least one cylinder having a combustion chamber and a spark plug, with an ignition point of the spark plug outside the combustion chamber in one with the Combustion chamber fluidically connected antechamber is arranged. It is provided that the internal combustion engine is provided and designed to at least temporarily produce a scavenging mixture of fuel and fresh gas by means of a mixture formation device outside of the combustion chamber and the antechamber and to introduce it directly into the antechamber for scavenging.

The advantages of such a configuration of the drive device and such a procedure have already been pointed out. Both the drive device and the method for operating it can be further developed according to the explanations within the scope of this description, so that reference is made to them in this respect.

• 1 eine schematische Darstellung einer Brennkraftmaschine mit einer Gemischbildungseinrichtung und die
• 2 eine schematische Darstellung der Gemischbildungseinrichtung.

The invention is explained in more detail below with reference to the exemplary embodiments illustrated in the drawing, without restricting the invention. The show

• 1 a schematic representation of an internal combustion engine with a mixture formation device and the
• 2 a schematic representation of the mixture formation device.

The 1 shows a schematic representation of an internal combustion engine 1 for a motor vehicle, not shown in detail, which has at least one cylinder with a combustion chamber 2 and a spark plug 3 . An ignition point of the spark plug 3 is arranged outside the combustion chamber 2 in an antechamber 4 which is fluidically connected to the combustion chamber. In this respect, the spark plug 3 is a prechamber spark plug. The spark plug 3 serves to ignite a combustion chamber mixture of fresh gas and fuel present in the combustion chamber 2 . The combustion chamber mixture is ignited indirectly in that a prechamber mixture present in the prechamber 4 is first ignited by means of the spark plug 3 . Combustion of the pre-chamber mixture propagates into the combustion chamber 2 via at least one passage opening, via which the pre-chamber 4 is fluidically connected to the combustion chamber 2, and in the process ignites the combustion chamber mixture.

After the combustion of the pre-chamber mixture, combustion gases can be present in the pre-chamber 4, which change a composition of a subsequently formed pre-chamber mixture and prevent or even completely suppress stable combustion. It is therefore provided that the antechamber 4 is flushed at least temporarily. For this purpose, the internal combustion engine 1 has a mixture formation device 5 by means of which a scavenging mixture is generated outside of the combustion chamber 2 and the antechamber 4 .

The scavenging mixture is introduced at least temporarily into the antechamber 4 via a scavenging channel directly into the antechamber 4 by means of a valve device 6 . Through that into the Vorkam mer 4 introduced scavenging mixture are present in the antechamber 4 forced combustion gases via the at least one passage opening into the combustion chamber 2.

After the pre-chamber 2 has been flushed, a further flushing mixture can be introduced into the pre-chamber 2 by means of the mixture-forming device 5, as a result of which the pre-chamber mixture provided for the ignition is formed. Additionally or alternatively, internal combustion engine 1 has a fuel injector 7 for introducing fuel into combustion chamber 2 . The combustion chamber mixture is generated by introducing fuel into the combustion chamber 2 by means of the fuel injector 7 . It can be provided here that the pre-chamber mixture is formed at least partially from the combustion chamber mixture, for example by this being forced into the pre-chamber 4 by a stroke movement of a piston of the cylinder.

The 2 shows a schematic representation of the mixture-forming device 5. The mixture-forming device 5 has a mixing chamber 8 in which the scavenging mixture is generated by swirling fuel in fresh gas. The fuel is conveyed by means of fresh gas, which flows through a driving nozzle 9 into the mixing chamber 5 and serves as a driving medium. The fresh gas is conveyed in the direction of the mixing chamber 8, for example by means of a compressor of an exhaust gas turbocharger (not shown in detail) or a compressor of the internal combustion engine 1.

Opening the valve device 6 releases a flow connection between the mixing chamber 8 and the antechamber 2 . The fresh gas conveyed in the direction of the mixing chamber 8 flows via a motive medium inlet 10 into a motive nozzle channel 11 of the motive nozzle 9 . The fuel is introduced into the driving nozzle channel 11 via a fuel inlet 12 by a suction effect of the fresh gas flowing through the driving nozzle channel 11 . The fuel and the fresh gas flow through a propellant medium outlet 13 into the mixing chamber 8 and form the scavenging mixture by swirling.

A mixing chamber pressure present in the mixing chamber 8 is measured by a pressure sensor 14 . The rinsing mixture is introduced into the antechamber 4 at least temporarily over an introduction time period selected as a function of the measured mixing chamber pressure. For this purpose, the valve device 6 is opened for the duration of the introduction period, so that the flow connection between the mixing chamber 8 and the antechamber 4 is released. After the introduction period has elapsed, the valve device 6 is closed, so that the flow connection between the mixing chamber 8 and the antechamber 4 is interrupted.

The mixture formation device 5 is preferably designed as a rail. This means that, in addition to the valve device 6 , there is at least one further valve device, not shown in detail, via which the mixing chamber 8 is connected to a further antechamber of a further cylinder of the internal combustion engine 1 . The mixture formation device 5 can thus provide the scavenging mixture for a plurality of cylinders of the internal combustion engine 1 .

Reference List

1

internal combustion engine

2

combustion chamber

3

spark plug

4

antechamber

5

mixture formation device

6

valve device

7

fuel injector

8th

mixing chamber

9

driving nozzle

10

motive medium inlet

11

motive nozzle channel

12

fuel inlet

13

motive medium outlet

14

pressure sensor

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102020133434 A1 [0002]

Claims (10)

Method for operating an internal combustion engine (1) for a motor vehicle, which has at least one cylinder having a combustion chamber (2) and a spark plug (3), with an ignition point of the spark plug (3) outside the combustion chamber (2) in one with the combustion chamber (2) is arranged in a fluidically connected antechamber (4), characterized in that at least temporarily a scavenging mixture of fuel and fresh gas is produced by means of a mixture-forming device (5) outside the combustion chamber (2) and the antechamber (4) and is used for scavenging the antechamber (2nd ) is introduced directly into the antechamber (2). procedure after claim 1 , characterized in that the scavenging mixture is generated by swirling fuel in fresh gas in a mixing chamber (8) of the mixture-forming device (5). Method according to one of the preceding claims, characterized in that the fuel is conveyed by means of a propellant medium flowing through a propellant nozzle (9) into the mixing chamber (8). Driver according to one of the preceding claims, characterized in that the fresh gas is used as the propellant medium. Method according to one of the preceding claims, characterized in that the fresh gas is conveyed in the direction of the mixing chamber (8) by means of a compressor, in particular a compressor of an exhaust gas turbocharger or a compressor of the internal combustion engine (1). Method according to one of the subsequent claims, characterized in that a mixing chamber pressure present in the mixing chamber (8) is measured by means of a pressure sensor (14) and the flushing mixture is introduced into the antechamber (4) over a period of time selected as a function of the measured mixing chamber pressure. Method according to one of the preceding claims, characterized in that during one working cycle of the cylinder, a fluid is introduced directly into the antechamber (4) in addition to the scavenging mixture. Method according to one of the preceding claims, characterized in that fresh gas or a further flushing mixture is used as the fluid, the further flushing mixture having the same composition as the flushing mixture or a different composition from the composition of the flushing mixture. Method according to one of the preceding claims, characterized in that the fluid to be introduced into the antechamber (4) is provided by means of the mixture-forming device (5) or a further mixture-forming device present in addition to the mixture-forming device (5). Internal combustion engine (1) for a motor vehicle, in particular for carrying out the method according to one or more of the preceding claims, the internal combustion engine (1) having at least one cylinder having a combustion chamber (2) and a spark plug (3), an ignition point of the spark plug (3) is arranged outside of the combustion chamber (2) in an antechamber (4) which is fluidically connected to the combustion chamber (2), characterized in that the internal combustion engine is provided and designed for this purpose, at least at times a scavenging mixture of fuel and fresh gas by means of a mixture formation device ( 5) outside of the combustion chamber (2) and the antechamber (4) and to introduce it directly into the antechamber (4) for flushing the antechamber (4).

Images