DE102014226843A1 - Method and device for bidirectionally controlling a gas flow in a combustion chamber bypass line bypassing a combustion chamber of a supercharged internal combustion engine - Google Patents

Abstract

The invention relates to a method for operating an engine system (1) with a supercharged internal combustion engine (2), the fresh air via an air supply system (4) and discharged from the combustion exhaust gas via an exhaust discharge system (5), wherein the air supply system (4) and the combustion chamber bypass line (8) connecting the exhaust gas removal system (5) is provided with a variably adjustable combustion chamber bypass valve (82) arranged therein, wherein the combustion chamber bypass valve (82) at a positive pressure difference between a Saugrohrdruck in the air supply system (4) and an exhaust back pressure in the exhaust discharge system (5) is adjusted depending on an operating state of the engine system (1).

Description

Technical area

The invention relates to supercharged internal combustion engines, such as internal combustion engines with a combustion chamber bypass line through which gases between an intake and an exhaust tract can be passed to a combustion chamber over. Furthermore, the present invention relates to measures for controlling such gas flow through a combustion chamber bypass line for a supercharged internal combustion engine.

State of the art

Exhaust gas recirculation conduits may be provided in prior internal combustion engines that are controlled to recirculate some of the combustion exhaust gases into an intake manifold of the air supply system, for example, to reduce the emissions of nitrogen oxides in the middle and lower load ranges of the internal combustion engine. In operating areas where a supercharger provides compressed fresh air, there is a reverse pressure differential between the intake and exhaust tracts such that no combustion exhaust gas can enter the air supply system. In this case, the exhaust gas recirculation line can be closed either passively by a check valve or actively by a controllable exhaust gas recirculation valve.

The publication US 8,783,020 B2 describes an exhaust system for an internal combustion engine having an exhaust line, which is connectable to an outlet side of the internal combustion engine, wherein in the exhaust line in the downstream direction at least one catalyst arranged and this is followed by a particle filter. Furthermore, a secondary air inlet opening for introducing compressed secondary air via at least one flutter valve in the exhaust line is provided in the exhaust line upstream of the particulate filter.

The publication WO 2009/115405 A1 discloses a method for regenerating a diesel particulate filter of an internal combustion engine, in particular a direct injection diesel engine having in its exhaust tract a catalyst and the diesel particulate filter. In this case, air is introduced into the exhaust tract such that it flows through the catalyst and the diesel particulate filter together with the exhaust gas of the internal combustion engine.

The publication DE 32 258 67 A1 discloses an internal combustion engine having an exhaust gas turbocharger whose charge outlet is connected to the intake manifold having a throttle valve and whose turbine inlet is connected to the exhaust line of the internal combustion engine and to a bypass line between the supercharger outlet and the turbine inlet. The bypass line is connected to the inlet line downstream of the throttle valve and includes a valve that shuts off the bypass line only when the exhaust gas pressure in the outlet line exceeds the boost pressure in the inlet line by a certain amount.

Disclosure of the invention

According to the invention there is provided a method of operating a combustion chamber by-pass valve in a supercharged combustion engine bypass combustion passage between an air supply system and an exhaust exhaust system according to claim 1 and an apparatus and an engine system according to the independent claims.

Further embodiments are specified in the dependent claims.

According to a first aspect, there is provided a method of operating an engine system with a supercharged internal combustion engine supplied with fresh air via an air supply system and exhausted from the combustion exhaust gas via an exhaust exhaust system, wherein a combustion chamber bypass line connecting the air supply system and the exhaust exhaust system has one therein variable adjustable combustion chamber bypass valve is provided. The combustion chamber by-pass valve will now operate even with a positive pressure difference between the air supply system and the exhaust discharge system, i. at an overpressure in the air supply system with respect to the exhaust gas discharge system, adjusted depending on an operating state of the engine system.

The above method utilizes a combustion chamber bypass conduit that connects a suction tube portion of the air supply system to a bypass region of the exhaust removal system. In the combustion chamber bypass line, a combustion chamber bypass valve is arranged. An idea of the above method is to operate the combustion chamber bypass valve so that in addition to a conventional mode of exhaust gas recirculation also in operating areas of the internal combustion engine in which there is a higher pressure than in the bypass as a result of charging by a supercharger in the Saugrohrabschnitt -Area of the exhaust tract, a flow of fresh air from the intake tract in this bypass area in a controlled manner is made possible.

This opens up several new types of operation, in particular by improving the efficiency and functionality of the Internal combustion engine are marked. Especially with dynamic load changes can be achieved by opening and closing the combustion chamber bypass valve, a quick intervention for boost pressure reduction or supercharging pressure, so that the response dynamics of the engine is improved.

By the modes in which a flow of fresh air from the intake tract is provided in the bypass area, in supercharged internal combustion engines, a critical load dynamics can be improved. That is, the engine response in specific operating ranges can be improved.

Furthermore, the adjustment of the combustion chamber by-pass valve, i. its opening cross-section over a predetermined time course are performed electronically controlled.

According to one embodiment, the adjustment of the combustion chamber bypass valve may be carried out in an Otto engine in an operating state in which a reduction of the torque from an upper load range, in particular within an operating range in which there is the positive pressure difference between the intake manifold pressure and the exhaust back pressure is requested, wherein the adjustment is carried out by driving the combustion chamber by-pass valve for opening or further opening, in particular without first controlling a throttle to close. Thus, by being able to allow a flow of fresh air from the suction pipe section into the bypass region of the exhaust gas removal system, it may be possible. to be dispensed with a Schubumluftsystem to reduce high pressure on the output side of a compressor of a charging device in a mode of rapid load reduction.

It may be provided that the combustion chamber bypass valve is permanently opened for providing a permanent air flow through the combustion chamber bypass line into the exhaust gas discharge system in an upper part-load range under increased boost pressure, wherein in an operating state in which an increase of a load in a charging operation area, ie is requested in a service area in which a charge is made, the combustion chamber bypass valve is driven to further or complete closing. It may be necessary to initiate a stationary bypass air flow downstream to protect against catalyst cooling.

In particular, the adjustment of the combustion chamber bypass valve can be carried out in an operating state in which a cleaning of the combustion chamber bypass line and / or the combustion chamber bypass valve is to be made. The adjustment may be performed, for example, by sequentially opening and closing the combustion chamber by-pass valve for a predetermined period of time.

When the combustion chamber bypass line is operated as exhaust gas recirculation, it can become carbonized or spoiled, as a result of which its free cross section (passage cross section) can change and the functionality of the combustion chamber bypass valve arranged therein can be impaired. The ability to cause a flow of fresh air from the Saugrohrabschnitt in the bypass area, a cleaning effect of the combustion chamber bypass line can be achieved by backwashing with fresh air.

It can be provided that the combustion chamber bypass valve is actuated at a negative pressure difference between the intake manifold pressure in the air supply system and the exhaust gas back pressure in the exhaust system according to a predetermined exhaust gas recirculation control.

According to one embodiment, the adjustment of the combustion chamber bypass valve can be carried out in an operating state in which a catalyst of the engine system is to be heated to an operating temperature with a gasoline engine as an internal combustion engine, wherein the combustion space bypass valve for the middle to upper load range Open is driven to direct fresh air into the exhaust system, and the combustion is performed in the gasoline engine with a fuel surplus. This leads to an afterburning, which brings the catalyst to a desired operating temperature.

By introducing fresh air into the exhaust gas discharge portion, in an internal combustion engine configured as a gasoline engine, secondary air addition in a charge operating region, i. an operating region in which charging by a charging device takes place, i. e. the catalyst heating can be accelerated in the sense of lower tailpipe emisions. In the lower load range is additionally used on Spätzündwinkelmaßnahmen. This can be used to replace a conventional secondary air injection system.

It can be provided that the adjustment of the combustion chamber bypass valve is carried out in an operating state in which in an upper part load range in a stoichiometric operation of the internal combustion engine components in the exhaust system, eg a lambda probe or a catalyst of the engine system with a gasoline engine as Internal combustion engine to be cooled, wherein the adjustment is carried out by driving the combustion chamber bypass valve to open or for further opening. This can be dispensed with internal cooling by Gemischanfettung, resulting in fuel savings.

According to another aspect, there is provided an apparatus for operating an engine system with a supercharged internal combustion engine supplied with fresh air via an air supply system and exhausted from the combustion exhaust via an exhaust evacuation system, wherein a combustion chamber bypass conduit connecting the air supply system and the exhaust evacuation system is disposed therein variable adjustable combustion chamber bypass valve is provided. The device is designed to adjust the combustion chamber bypass valve at any pressure difference between the air supply system and the Abgasabführungssystem depending on an operating condition of the engine system variable, in particular continuously or in more than two stages.

Brief description of the drawings

Embodiments are explained below with reference to the accompanying drawings. Show it:

1 a schematic representation of an engine system with a supercharged internal combustion engine;

2 a flowchart for illustrating a method for operating the combustion chamber bypass valve of the engine system.

Description of embodiments

1 shows a schematic representation of an engine system 1 with a supercharged combustion engine 2 in which a number of cylinders 3 (Four in the present embodiment) is provided. Air gets to the cylinders 3 through appropriate intake valves via an air supply system 4 supplied and through appropriate exhaust valves via an exhaust discharge system 5 dissipated.

It is a charging device 6 provided a turbine 61 having that with an exhaust removal system 5 coupled to an exhaust enthalpy, which in one during operation of the internal combustion engine 2 discharged combustion exhaust gas is contained in mechanical energy for driving a compressor 62 in the air supply system 4 convert. These are the turbine 61 and the compressor 62 over a wave 63 mechanically coupled with each other.

The turbine 61 can be provided with a turbine actuator. The turbine actuator can be provided as a VTG turbine (VTG: variable turbine geometry), so that an adjustment of a turbine geometry, an efficiency of the turbine 61 can be adjusted. Alternatively, as a turbine position sensor, an adjustable wastegate valve in a turbine 61 be provided promptly wastegate line. The turbine efficiency indicates what proportion of the available exhaust gas enthalpy is converted into mechanical energy.

The turbine 62 is located in the air supply system 4 and serves to supply fresh air from the environment of the engine system 1 suck in and in a boost pressure section 41 under an increased pressure, the so-called boost pressure to provide. The boost pressure section 41 is through a throttle 7 limited, with the one air flow through a subsequent Saugrohrabschnitt 42 to the internal combustion engine 2 is controllable. The suction pipe section 42 is located between the throttle 7 and intake valves (not shown) of the cylinders 3 of the internal combustion engine 2 ,

Substantially immediately downstream of the exhaust valves (not shown) of the cylinders 3 of the internal combustion engine 2 opens a combustion chamber bypass line 8th in a bypass area 51 the exhaust discharge system 5 , The combustion chamber bypass line 8th connects the exhaust system 5 with the suction pipe section 42 , In the combustion chamber bypass line 8th is a combustion chamber bypass valve 82 provided an exhaust gas mass flow from the exhaust gas bypass section 51 in the suction pipe section 42 Adjust according to conventional methods known per se. For this purpose, conventional exhaust gas recirculation regulations are provided, especially in low and medium load ranges in which the pressure in the bypass area 51 the exhaust discharge system 5 is higher than an intake manifold pressure in Saugrohrabschnitt 42 , an exhaust gas mass flow in the Saugrohrabschnitt 42 to achieve a desired exhaust gas recirculation rate.

It is an electronic control unit 10 provided the internal combustion engine 2 can operate to provide a specific torque or a specific load. The control unit 10 can state variables obtained via sensors or suitable system models, such as an air mass flow on the input side of the compressor 62 , a measured boost pressure in the boost pressure section 41 , a speed of the internal combustion engine 2 and the like, positioner of the internal combustion engine 2 control so that the desired torque or the desired load is achieved. The position encoders include, for example, the turbine actuator, the throttle 7 , the combustion chamber bypass valve 82 and the same. As described above, the control unit 10 provide, at a negative pressure difference between the Saugrohrabschnitt 42 and the bypass area 51 the combustion chamber bypass valve 82 to control according to the function of a conventional exhaust gas recirculation valve, so as to set a certain exhaust gas recirculation rate, which is set according to an exhaust gas recirculation control.

While conventional exhaust gas recirculation control provides, the combustion chamber bypass valve 82 at a positive pressure difference between the intake manifold pressure in the Saugrohrabschnitt 42 and the pressure in the bypass area 51 ie an overpressure in the suction pipe section 42 concerning the bypass area 51 , to close, are now provided modes in which the exhaust gas recirculation valve outflow of fresh air from the Saugrohrabschnitt 42 in the exhaust system 5 allows.

In the following, various operating modes are described in which an outflow of fresh air from the Saugrohrabschnitt 42 in the exhaust system 5 is allowed.

In 2 a flow chart is shown, which describes methods in which in certain operating modes, a discharge of fresh air from the Saugrohrabschnitt 42 in the exhaust system 5 is allowed.

In step S1, it is first checked whether there is a positive pressure difference between a suction pipe pressure in the suction pipe section 42 and an exhaust back pressure in the bypass area 51 is present. If this is the case (alternative: yes), the method is continued with step S2, otherwise (alternative: no) is returned to step S1.

In step S2, it is checked whether a specific operating state exists. If this is the case (alternative: yes), the method is continued with step S3, otherwise (alternative: no) is returned to step S1.

In step S3, depending on the operating state of the internal combustion engine 2 the combustion chamber bypass valve 82 adjusted for a time dependent on the operating condition, so that in particular a certain opening behavior is effected.

In the following, for example, an operating state can be considered as the operating state of step S2, in which case an internal combustion engine designed as a diesel engine or as a gasoline engine 2 a reduction of the torque, eg to a medium load range of an upper load range of the internal combustion engine 2 is requested.

In conventional operating methods, it is intended to lower the boost pressure and the throttle valve when requesting the reduction of the torque 7 (transient) to reduce the intake manifold pressure quickly and then with the engine bypass valve open 82 to recycle a desired amount of exhaust gas to reduce nitrogen oxide emissions. In this method of operation, usually the throttle losses increase, whereby a motor efficiency is reduced.

Instead, when requesting a reduction in torque from the upper load range with the throttle open, the combustion chamber by-pass valve 82 be opened quickly (further or completely), so that part of the air in the suction pipe section 42 in the Abgasabführungsabschnitt 5 can flow out. This leads to a reduction of the intake manifold pressure and thereby to a lower cylinder filling with fresh air. This reduces the throttle losses in a designed as gasoline engine internal combustion engine 2 and it becomes the efficiency of the internal combustion engine 2 improved over the previous approach. The compression end temperature and the combustion peak temperature are reduced, which may have a positive effect, especially in a diesel engine: The nitrogen oxide production in the internal combustion engine is reduced, which is achieved in a conventional manner by the counter-flow in the combustion chamber bypass line 8th With exhaust gas recirculation it can only reach in the lower load range and is still available there. Here, the gasoline engine continues to be throttled, in the case of the diesel engine, the complete take-back of the charge, which takes place in both engine types, is sufficient.

Furthermore, in gasoline engines, the discharge of compressed fresh air from the Saugrohrabschnitt 42 via the combustion chamber bypass line 8th be used for the rapid reduction of boost pressure, parallel to the opening of the wastegate, allowing any diverting air to the compressor 62 the charging device 6 is not needed. For a medium load range, a permanent air flow through the combustion chamber bypass line 8th in the exhaust system 5 provided that the catalyst temperature does not decrease too much. There is an increased risk of catalyst cooling, the bidirectional combustion chamber bypass valve 82 be designed as a three-way valve between Saugrohreinspeise- / withdrawal point and two Abgaseinspeise- / removal points (in each case before and after the main catalyst).

Hereinafter, as the operating state of step S2, an operating state is considered in an engine designed as a diesel engine 2 a fast load increase from a medium load range to a higher load range is requested. In this operating state, in the case of an already at least partially opened combustion chamber bypass valve 82 , in which fresh air from the Saugrohrabschnitt 42 in the bypass area 51 flows out, the combustion chamber bypass valve 82 (further or completely) be closed to quickly the intake manifold pressure and thus the boost pressure in the boost pressure section 41 to increase. Thus, a load control by the combustion chamber bypass valve 82 be made so that when increasing a load request from a charging area, ie in an operating area in which a charge takes place, and in which the combustion chamber bypass valve 82 at least partially open, a required charge pressure by further or complete closing of the combustion chamber bypass valve 82 can be set up quickly. This allows a faster charge pressure build-up than would be possible by controlling the turbine actuator. As a result, the dynamic behavior can be significantly improved in the case of a positive load request, since a fundamentally slow boost pressure change via the turbine actuator of the turbine 61 can be accelerated in two ways by a positive feedback effect. As a result of a stronger initial combustion by the accelerated filling structure, firstly, the exhaust gas temperature increases faster. Second, due to an increased gas flow rate through the combustion chamber, the enthalpy and thus the efficiency of the turbine of the charging device increases overall.

Hereinafter, as the operating state of the step S2, an operating state is considered in which a cleaning of the combustion chamber bypass line 8th or the combustion chamber bypass valve 82 can be made. Since the exhaust gas recirculation mode in the combustion chamber bypass line 8th Sooting / fouling may occur, it is convenient to use the combustion chamber bypass pipe 8th flushed or cleaned regularly or at predetermined times. This can be done by a suitable pulse-like opening and closing of the combustion chamber bypass valve 82 be achieved in a Aufladungsbetriebsbereich for a predetermined period of time, with a positive pressure difference between the Saugrohrabschnitt 42 and the bypass area 51 is present. By sequentially opening and closing, fresh air pulses are generated, released by the particulate deposits and into the exhaust discharge system 5 can be blown off.

Furthermore, it is necessary that this cleaning process be moment neutral, i. without a noticeable effect on driving behavior. This is rather uncritical in diesel engines, since small changes in the fresh air filling in the cylinder make only marginally noticeable. In the gasoline engine, on the other hand, the torque neutrality must be taken into account by means of a torque reserve (retained multiple air quantity at a later ignition angle).

In Instationärfall the cleaning process of the combustion chamber bypass line 8th Particle deposits in a load reduction from upper load ranges, ie at high boost pressure, done. In this way, the accelerated degradation of the boost pressure with a backwashing effect through the combustion chamber bypass line 8th combined to simultaneously clean the combustion chamber bypass pipe 8th to reach from a mocking. This cleaning process can be initiated with a detachment of stuck particles. This is done by appropriately opening and closing the combustion chamber bypass valve 82 (eg clocked with targeted bouncing). This can be followed by a moderate opening with the aim of high flow rate. This can be done either at predetermined times or as an initial phase at the beginning of each regular activation.

The conventional approach in supercharged diesel engines to significantly lower the boost pressure in a partial load range, has the disadvantage that a requested maximum boost pressure builds up only comparatively slowly and the torque-determining injection quantities can not be increased directly, otherwise over-greasing and soot emissions would be the result. In particular, in the middle load range and upper load range, therefore, a higher base charge by the charging device 6 be provided and the intake manifold pressure or the boost pressure via a variable setting of the combustion chamber bypass valve 82 be managed. The determined by the variable setting opening cross section of the combustion chamber bypass valve 82 then determines the into the Abgasabführungsabschnitt 5 flowing fresh air and at the same time the potential of fast filling and load increase (dynamics).

The combination of the conventional method for operating an exhaust gas recirculation system is not in conflict with the novel combustion chamber bypass system, through which outflow of fresh air from the Saugrohrabschnitt 42 in the bypass area 51 the exhaust discharge system 5 is possible. These operating ranges are across the direction of the pressure gradient in the combustion chamber bypass line 8th separated.

Hereinafter, the operating state of the step S2 is considered to be an operating state in which a catalyst of an engine system 1 with a gasoline engine as an internal combustion engine 2 can be heated to an operating temperature. At a Gasoline engine with active charging, ie the exhaust gas enthalpy is sufficient to a compression of fresh air in the boost pressure section 41 to reach, as is the case with medium to upper load ranges, the control unit 10 Provide the combustion chamber bypass valve 82 open to fresh air in the exhaust discharge tract 5 to conduct and there to achieve an afterburning using a light, for example, slightly rich combustion chamber mixture. Thereby, the known catalyst heating effect can be provided, for which conventionally a separate secondary air system would be required. In place of a secondary air pump then enters the exhaust-driven charging device 6 , so that it can be dispensed with the provision of the secondary air pump.

Hereinafter, the operating state of the step S2 is considered to be an operating state in which a catalyst of an engine system 1 with a gasoline engine as an internal combustion engine 2 to be cooled. For this purpose, in an upper load range at a stoichiometric operating state of the internal combustion engine 2 that is, no excess unburned fuel enters the exhaust gas removal system 5 , by introducing fresh air from the Saugrohrabschnitt 42 in the exhaust tract 5 a catalyst cooling can be achieved.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• US 8783020 B2 [0003]
• WO 2009/115405 A1 [0004]
• DE 3225867 A1 [0005]

Claims (13)

Method for operating an engine system ( 1 ) with a supercharged internal combustion engine ( 2 ), the fresh air via an air supply system ( 4 ) and from the combustion exhaust gas via an exhaust discharge system ( 5 ), wherein one of the air supply system ( 4 ) and the exhaust discharge system ( 5 ) connecting combustion chamber bypass line ( 8th ) with a variably adjustable combustion chamber bypass valve arranged therein ( 82 ), wherein the combustion chamber bypass valve ( 82 ) at a positive pressure difference between a intake manifold pressure in the air supply system ( 4 ) and an exhaust backpressure in the exhaust discharge system ( 5 ) depending on an operating state of the engine system ( 1 ) is adjusted. Method according to claim 1, wherein the adjustment of the combustion chamber bypass valve ( 82 ) is performed according to a predetermined time course. The method of claim 1 or 2, wherein adjusting the combustion chamber by-pass valve ( 82 ) is performed in an operating state in which a reduction of the torque within an operating range in which the positive pressure difference between the intake manifold pressure and the exhaust gas back pressure is requested, is requested, wherein the adjustment by a driving of the combustion chamber by-pass valve ( 82 ) is carried out for opening or for further opening, in particular without a throttle flap ( 7 ) in the air supply system ( 4 ) to close. Method according to one of claims 1 to 3, wherein the combustion chamber bypass valve ( 82 ) for providing a permanent air flow through the combustion chamber bypass line ( 8th ) into the exhaust gas removal system ( 5 ), wherein in an operating state in which an increase of a load is requested, the combustion chamber bypass valve ( 82 ) is driven to further or complete closing. Method according to one of claims 1 to 3, wherein the adjustment of the combustion chamber by-pass valve ( 82 ) is carried out in an operating state in which a cleaning of the combustion chamber bypass line ( 8th ) and / or the combustion chamber bypass valve ( 82 ) should be made. The method of claim 5, wherein the adjusting is accomplished by sequentially opening and closing the combustion chamber by-pass valve (10). 82 ) is performed according to a predetermined drive pattern. Method according to one of claims 1 to 6, wherein the adjustment of the combustion chamber bypass valve ( 82 ) is carried out in an operating state in which in an engine designed as a diesel engine ( 2 ) a load increase is requested, which causes an increase in the boost pressure, wherein for adjusting the combustion chamber bypass valve ( 82 ) This is driven to further or complete closing. Method according to one of claims 1 to 7, wherein the combustion chamber bypass valve ( 82 ) at a negative pressure difference between the intake manifold pressure in the air supply system ( 4 ) and the exhaust back pressure in the exhaust system ( 5 ) is driven in accordance with a predetermined exhaust gas recirculation control. Method according to one of claims 1 to 8, wherein the adjustment of the combustion chamber by-pass valve ( 82 ) is carried out in an operating state in which a catalyst of the engine system ( 1 ) with a gasoline engine as internal combustion engine ( 2 ) is to be heated to an operating temperature, wherein the combustion chamber bypass valve ( 82 ) is opened to allow fresh air into the exhaust gas discharge system ( 5 ), and the combustion is carried out in the gasoline engine with a fuel surplus. Method according to one of claims 1 to 9, wherein the adjustment of the combustion chamber by-pass valve ( 82 ) is carried out in an operating state in which in a stoichiometric operation of the internal combustion engine ( 2 ) a catalyst of the engine system ( 1 ) with a gasoline engine as internal combustion engine ( 2 ), wherein the adjustment by driving the combustion chamber by-pass valve ( 82 ) is carried out for opening or for further opening. Device for operating an engine system ( 1 ) with an internal combustion engine ( 2 ), the fresh air via an air supply system ( 4 ) and from the combustion exhaust gas via an exhaust discharge system ( 5 ), wherein one of the air supply system ( 4 ) and the exhaust discharge system ( 5 ) connecting combustion chamber bypass line ( 8th ) with a variably adjustable combustion chamber bypass valve arranged therein ( 82 ) is provided, wherein the device is adapted to the combustion chamber bypass valve ( 82 ) at a positive pressure difference between the air supply system ( 4 ) and the exhaust discharge system ( 5 ) depending on an operating state of the engine system ( 1 ) to adjust. Computer program which, when stored in a data processing device ( 10 ) is adapted to perform all the steps of a method according to any one of claims 1 to 10. A machine-readable storage medium on which a computer program according to claim 12 is stored.

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