阅读说明：本技术 从内燃机的再生空气系统排出冷凝物 (Draining condensate from a regeneration air system of an internal combustion engine ) 是由 M·格伦德 于 2021-05-19 设计创作，主要内容包括：本发明涉及一种用于运行内燃机的方法,其中,内燃机具有燃烧发动机、带有集成在其中的待根据需要主动再生的废气后处理装置的排气系和再生空气系统。在再生空气系统的再生空气线路中集成有再生空气系统的再生空气输送装置和再生空气阀,再生空气线路将环境空气通入部与排气系的置于废气后处理装置上游的区段相连接。在燃烧发动机的运行期间暂时打开再生空气阀,而不同时将废气在废气后处理装置之前添加以用于氧化后燃烧的碳氢化合物。再生空气阀的打开为了从再生空气系统排出冷凝物而非为了废气后处理装置的再生进行。补充地或备选地可设置成在燃烧发动机的非运行期间为了冷凝物的排出暂时打开再生空气阀。(The invention relates to a method for operating an internal combustion engine, wherein the internal combustion engine has a combustion engine, an exhaust system with an exhaust gas aftertreatment device integrated therein to be actively regenerated as required, and a regeneration air system. The regeneration air supply and the regeneration air valve of the regeneration air system are integrated into a regeneration air line of the regeneration air system, which connects the ambient air inlet to a section of the exhaust system upstream of the exhaust gas aftertreatment device. The regeneration air valve is temporarily opened during operation of the combustion engine without simultaneously adding exhaust gas before the exhaust gas aftertreatment device for oxidizing the post-combusted hydrocarbons. The regeneration air valve is opened for the purpose of discharging condensate from the regeneration air system and not for the purpose of regeneration of the exhaust gas aftertreatment device. In addition or alternatively, it can be provided that the regeneration air valve is temporarily opened for condensate removal during non-operation of the combustion engine.)

1. Method for operating an internal combustion engine having a combustion engine (1), an exhaust system (10) with an exhaust gas aftertreatment device (11) to be regenerated as required, and a regeneration air system (14), wherein a regeneration air line (15) of the regeneration air system (14) connects an ambient air inlet (6) with a section of the exhaust system (10) which is located upstream of the exhaust gas aftertreatment device (11), and wherein a regeneration air supply device (16) and a regeneration air valve (17) of the regeneration air system (14) are integrated in the regeneration air line (15), characterized in that the regeneration air valve (14) is temporarily opened for the discharge of condensate during operation of the combustion engine (11) without simultaneously adding exhaust gas before the exhaust gas aftertreatment device (11) for oxidizing post-combusted hydrocarbons and/or before the combustion engine (11) The machine (11) is temporarily turned on during non-operation.

2. Method according to claim 1, characterized in that the regeneration air delivery device (16) is operated during operation of the combustion engine (1) during the opening of the regeneration air valve (17).

3. Method according to claim 1 or 2, characterized in that the regeneration air valve (17) is opened during coasting operation of the combustion engine (1).

4. Method according to any of the preceding claims, characterized in that the regeneration air delivery device (16) is not operated during non-operation of the combustion engine (1) during the opening of the regeneration air valve (17).

5. Method according to one of the preceding claims, characterized by being used in an internal combustion engine, in which the section of the regeneration air line (15) which extends between the regeneration air valve (17) and the opening of the regeneration air line (15) into the exhaust gas system (10) extends continuously downwards.

6. Method according to any of the preceding claims, characterized in that the regeneration air valve (17) is opened as wide as possible.

7. Method according to any of the preceding claims, characterized by being used in an internal combustion engine, in which the regeneration air line (15) branches off from the fresh air system (5) of the internal combustion engine downstream of the air filter (7).

8. The method according to any one of the preceding claims, characterized by being used in an internal combustion engine, in which the exhaust gas aftertreatment device (11) is or comprises a particle filter (13).

9. The method according to any one of the preceding claims, characterized by being used in an internal combustion engine, in which the combustion engine (1) is constructed to be ignited externally.

Technical Field

The invention relates to a method for operating an internal combustion engine (Brennkraftmasschine) having a combustion engine (Verbrennungsmotor), an exhaust system (Abgasstrang) having an exhaust gas aftertreatment device to be actively regenerated as required, and a regeneration air system, wherein a regeneration air line (Regenerationluffluentung) of the regeneration air system connects an ambient air inlet (Umgebungsluftmuendung) to a section of the exhaust system upstream of the exhaust gas aftertreatment device, and wherein a regeneration air supply and a regeneration air valve of the regeneration air system are integrated in the regeneration air line. The internal combustion engine can be part of a motor vehicle.

Background

Such an exhaust gas aftertreatment device to be actively regenerated as required may be, in particular, a particulate filter for reducing particles in the exhaust gas which is generated in the combustion engine of the internal combustion engine during the combustion process and which is to be conducted out into the surroundings via the exhaust system. The particulate filter must generally be regenerated when a defined load limit is reached in order to maintain its functionality. For this purpose, it is heated temporarily to a temperature which is generally between 600 ℃ and 650 ℃ if the reduction in the oxidation temperature of the carbon black particles is not achieved by the addition of additives.

Heating the exhaust gas aftertreatment device to the temperature necessary for regeneration is usually achieved by a corresponding increase in the temperature of the exhaust gas, for which different measures are known, in particular in the interior of the motor. However, if the exhaust gas aftertreatment device to be regenerated is integrated into the exhaust system at a relatively large distance from the combustion engine, the relatively hot exhaust gas generated by the combustion engine due to the measures inside the respective motor can already be cooled down so strongly when reaching the exhaust gas aftertreatment device that it is therefore no longer possible to easily regenerate the exhaust gas aftertreatment device. In such a case, it may be provided to add (after) the exhaust gas upstream of the exhaust gas aftertreatment device with the hydrocarbons combusted before or after oxidation in the exhaust gas aftertreatment device, whereby (again) the exhaust gas may be heated to a temperature sufficient for the regeneration of the exhaust gas aftertreatment device. The oxygen required for such an oxidative post-combustion (Nachverbrennung) can be introduced into the exhaust system as part of the ambient air via the regeneration air line of the regeneration air system. The regeneration air supply device and the regeneration air valve can be integrated into the regeneration air line.

Condensate (Kondensat), in particular condensed water, in the regeneration air line and in particular in the region of the regeneration air delivery device and/or the regeneration air valve can accumulate with the regeneration air valve closed, which can be problematic in particular if the condensate freezes due to correspondingly low ambient temperatures. This may temporarily prevent a defect-free use of the regeneration air system. However, the amount of condensate accumulated by the regeneration air is generally small. Furthermore, condensate in the regeneration air system generally does not accumulate in large quantities due to the periodic use of the regeneration air system, so that the necessity of actively preventing such an accumulation of condensate in the regeneration air system has not been seen so far.

Document US 2009/0038301 a1 discloses an internal combustion engine with a three-way catalyst integrated into the exhaust system belonging thereto and with a device for secondary air injection (sekundaerlufeinblasung). Such secondary air injection serves to oxidatively post-combust the hydrocarbons which are intentionally enriched in the exhaust gas upstream of the catalyst, in order to cause the catalyst to heat up as quickly as possible until its activation or Light-Off temperature (Light-Off-temperature) is reached. The device comprises a secondary air line, in which an air filter, a secondary air supply, a secondary air valve and a Reed valve (Reed-vent) having the function of a return lock valve (rueckstm specerventil) are integrated. In order to avoid freezing of the condensate accumulating in the secondary air line and in particular in the secondary air supply device when the external temperature is below freezing, it is provided that, after the operation of the internal combustion engine has ended, an outlet valve (Drainageventil) integrated into an outlet line branching off from the secondary air supply device is first opened. The secondary air supply is then operated and the secondary air valve is opened in order to flush condensate still in the secondary air line.

Disclosure of Invention

The aim of the invention is to ensure reliable operation of a regeneration air system of an internal combustion engine.

This object is achieved by operating an internal combustion engine according to the method of the invention. Advantageous embodiments of the method according to the invention emerge from the following description of the invention.

According to the invention, a method is provided for operating an internal combustion engine, wherein the internal combustion engine has a combustion engine, an exhaust system with an exhaust gas aftertreatment device integrated therein to be actively regenerated as required, and a regeneration air system. A regeneration air supply device is integrated in a regeneration air line of the regeneration air system, which connects the ambient air inlet to a section of the exhaust system (directly or indirectly) which is located upstream of the exhaust gas aftertreatment device, and preferably a regeneration air valve of the regeneration air system is located downstream of the regeneration air supply device. According to the invention, the regeneration air valve is temporarily opened during operation of the combustion engine without simultaneously adding exhaust gas before the exhaust gas aftertreatment device for oxidizing the post-combusted hydrocarbons. The opening of the regeneration air valve according to the invention therefore takes place (only) for the purpose of discharging condensate from the regeneration air system and not for the purpose of regeneration of the exhaust gas aftertreatment device. In addition or alternatively, it may be provided within the scope of the method according to the invention that the regeneration air valve is temporarily opened for condensate removal during non-operation of the combustion engine.

The connection of the regeneration air system to the pilot fluid of the exhaust system is established by opening the regeneration air valve, thereby enabling condensate which accumulates in the regeneration air system and in particular in the regeneration air valve to be conducted away. It is namely recognized that for certain situations, in the use of internal combustion engines with a regeneration air system and in particular motor vehicles comprising such internal combustion engines, a relevant amount of condensate can accumulate in the regeneration air system and can influence the functionality of the regeneration air system due to icing on the basis of correspondingly low ambient temperatures. This can be particularly important if such a motor vehicle is used for a relatively long period of time, for example also months or years, so that it is not necessary to actively regenerate the exhaust gas aftertreatment device using a regeneration air system. Under these circumstances, the condensate which accumulates in the deactivated regeneration air system can reach relevant quantities, which is particularly suitable if the operation of the motor vehicle takes place in climatic conditions which are characterized by a relatively high temperature and air humidity during this period. If such a motor vehicle is then operated for a short period at ambient temperatures below freezing, for example because the motor vehicle is driven into an area with corresponding climatic conditions, there is the possibility that condensate which has previously accumulated in the regeneration air system freezes and influences the functionality of the regeneration air system. This potential problem is prevented by the method according to the invention.

According to a preferred embodiment of the method according to the invention, it can be provided that the regeneration air supply device is operated during the opening of a regeneration air valve, which is carried out for condensate removal during operation of the combustion engine. The air flow generated by means of the regeneration air supply device can then advantageously support the entrainment of condensate out of the regeneration air system.

In order to avoid that the amount of air which is introduced into the exhaust system via the regeneration air line when the regeneration air valve is opened during operation of the combustion engine, which is effected for the purpose of discharging condensate, negatively influences the operation of the combustion engine, for example because the exhaust gas composition determined by means of a so-called Lambda sensor (Lambda sensor) is thereby changed, it can preferably be provided that the regeneration air valve is opened, in particular, only during coasting (Schubbetrieb) of the combustion engine, that is to say in the external drive of the combustion engine and therefore without (positive) power output of the combustion engine. This can be particularly important if the regeneration air supply device is operated simultaneously with the opening of the regeneration air valve, since then a relatively large air mass flow is introduced into the exhaust system via the regeneration air line.

The operation of the regeneration air supply device can also be provided if a regeneration air valve is opened for the purpose of discharging condensate during non-operation of the combustion engine. However, it is preferably provided that the regeneration air supply device is not operated during such opening of the regeneration air valve, as a result of which noise emissions associated with such operation can be avoided.

In an internal combustion engine which is advantageously suitable for carrying out the method according to the invention, the section of the regeneration air line which extends continuously downward extends between the regeneration air valve (and in particular the valve seat of the regeneration air valve) on the one hand and the opening of the regeneration air line into the exhaust system on the other hand. This achieves that the condensate can flow into the exhaust system only with the aid of gravity drive when the regeneration air valve is opened.

It is furthermore preferably provided that the regeneration air line branches off from the fresh air system (Frischgasstrang) of the internal combustion engine downstream of the air filter. The regeneration air line then connects the exhaust system indirectly via a section of the fresh gas system to the ambient air inlet (of the fresh gas system). This makes it possible to route the air which has been cleaned by means of the air filter of the fresh air system, as required (for the discharge of the regeneration air system and for the regeneration of the exhaust gas aftertreatment device), through the regeneration air line, which avoids contamination of the exhaust system and in particular of the exhaust gas aftertreatment device by particles carried along by this air. The structural design of the internal combustion engine can thus be simplified compared to the same possible integration of a separate air filter into the regeneration air line.

According to a preferred embodiment of the method according to the invention, it can be provided that the regeneration air valve is opened as wide as possible for condensate to be discharged. This makes it possible, on the one hand, to achieve the fastest possible and complete removal of condensate. Furthermore, a cleaning function for the regeneration air valve can be achieved in that possible deposits, in particular at the valve body and at the surface of the regeneration air valve which guides the movement of the valve body, can be removed by the opening and closing movement which is as far as possible.

The exhaust gas aftertreatment device of the internal combustion engine, which operates within the scope of the method according to the invention, may be in particular a particle filter or it comprises at least one such particle filter. However, the exhaust gas aftertreatment device of an internal combustion engine operated according to the invention may also be NO, for example_XStorage catalysts or including such NO_XThe catalyst is stored. In NO_XTemporary storage of Nitrogen Oxides (NO) in a storage catalyst during certain operating states of an internal combustion engine_X) It cannot be reduced to nitrogen (N) and oxygen (O) in these operating states₂). In such NO_XThere is also a need in storage catalysts to regenerate them when a defined load limit is reached in order to maintain their functionality. In addition, it is possible toIt is necessary to add such NO_XThe storage catalyst is desulfurized at regular intervals, which is also referred to as desulphatation (desulfation), but according to the invention should fall under the concept of regeneration. Such desulfurization may be necessary because the sulfur normally contained in the fuel may react with NO_XStorage material (material) reaction of the storage catalyst, whereby NO is made available_XThe amount of storage material used for storage can be reduced. Sulfate (e.g., barium Sulfate) is produced, which is very resistant to high temperatures and which is resistant to simple NO_XAnd does not decompose at sufficient exhaust gas temperatures for regeneration. For desulfurization, NO is added_XThe storage catalyst is heated to a temperature between 600 ℃ and 650 ℃ if necessary.

The method according to the invention is particularly applicable in internal combustion engines in which the combustion engine is configured to be ignited from an external source and is also especially regulated in quantity, that is to say as a gasoline engine, since, in particular in such gasoline engines, depending on the nature of use (nutsungsverhalten), it can occur that active regeneration is not carried out due to the addition of hydrocarbons to the exhaust gas upstream of the exhaust gas aftertreatment device provided for this purpose and due to the use of the regeneration air system for a very long period of time, since the gasoline engine is operated frequently enough with such a high power output that the exhaust gas aftertreatment device is (passively) regenerated at the same time. In principle, however, the internal combustion engine operated according to the invention can comprise any combustion engine of any design, for example a (self-igniting and mass-regulated) diesel engine or a mixture of a gasoline engine and a diesel engine (for example a combustion engine with homogeneous charge compression ignition).

The invention also relates to a motor vehicle having an internal combustion engine to be operated according to the invention and to a method for operating such a motor vehicle, wherein the internal combustion engine can be used in particular to provide (directly or indirectly) driving power for the motor vehicle. Such a motor vehicle may in particular be a wheel-based motor vehicle (preferably a passenger or cargo vehicle) which is not driven on a rail.

Drawings

The invention will be explained in detail below on the basis of embodiments shown in the drawings. Shown partially in schematic form in the drawings:

figure 1 shows an internal combustion engine according to the invention,

FIG. 2 shows a regeneration air system of an internal combustion engine, an

Fig. 3 shows a partial longitudinal section through the regeneration air valve of the regeneration air system.

Detailed Description

Fig. 1 shows a simplified diagram of an internal combustion engine for a motor vehicle, which is suitable for carrying out the method according to the invention. The internal combustion engine comprises a combustion engine 1, which is configured exemplarily in the form of a reciprocating piston motor with four cylinders 2 arranged in a row. The cylinder 2 delimits a combustion chamber 4 with a reciprocating piston 3 guided therein and a cylinder head (not shown) respectively. During operation of the combustion engine 1 and therefore of the internal combustion engine, fresh gas is supplied to the combustion chambers 4 via the fresh gas system 5. The fresh gas is at least predominantly air, which is drawn in from the surroundings via the ambient air inlet 6 and which is subsequently conducted through the air filter 7 and then through the fresh gas compressor 8. The fresh gas compressor 8 is part of an exhaust gas turbocharger which furthermore comprises an exhaust gas turbine 9 integrated into an exhaust system 10 of the internal combustion engine. The exhaust gas generated during the combustion of the mixture quantity, which is formed by fresh gas and by fuel injected into the combustion chamber 4, for example, directly via a fuel injector (not shown), is conducted away via the exhaust system 10 and is conducted through the exhaust gas aftertreatment device 11. The exhaust gas aftertreatment device 11 has, in addition to a catalytic converter 12 arranged between the combustion engine 1 and the exhaust gas turbine 9, a particle filter 13, which is integrated into the exhaust system 10 downstream of the exhaust gas turbine 9 and therefore at a relatively large distance from the combustion engine 1. In this case, the particle filter 13 can also be arranged below the floor of the motor vehicle, which, in addition to the relatively large distance of the particle filter 13 from the combustion engine 1, can result in the exhaust gases already being cooled relatively strongly when they flow through the particle filter 13, due to the relatively exposed position.

In order to regenerate the particle filter 13 as required, it needs to be heated to a relatively high temperature, for example between 600 ℃ and 650 ℃, in order to burn off the particles present in the particle filter 13. In order to ensure such heating of the particle filter 13, the internal combustion engine comprises a regeneration air system 14 (see also fig. 2 and 3) which has a regeneration air line 15 which branches off from the section of the fresh gas system 5 between the air filter 7 and the fresh gas compressor 8 and which opens into the section of the exhaust gas system 10 between the exhaust gas turbine 9 and the particle filter 13. An electrically drivable regeneration air supply device 16 is integrated in the regeneration air line 15, and a regeneration air valve 17, which is shown in further detail in fig. 3, is located between the regeneration air supply device 16 and the opening of the regeneration air line 15 into the exhaust system 10. The regeneration air supply device 16 and the regeneration air valve 17 are controllable by means of a control device 18 of the internal combustion engine, for example by means of a central motor control.

By known measures internal to the motor, which can be used temporarily for regeneration of the particle filter 13 during operation of the combustion engine 1, a relatively high proportion of (unburned) hydrocarbons can be produced in the exhaust gas discharged from the combustion engine 1. These hydrocarbons are then oxidatively post-combusted in the exhaust system 10 before the particle filter 13, whereby the exhaust gas flowing through the particle filter 13 attains a sufficiently high temperature in order to ensure regeneration of the particle filter 13. The oxygen required for the post-oxidation combustion of hydrocarbons is introduced as part of the air into the exhaust system 10 by means of the regeneration air system 14 and is sucked in from the fresh air system 5 by means of the regeneration air supply device 16 with the regeneration air valve 17 open.

In order to drain off condensate that can accumulate within the regeneration air system 14 and in particular upstream of the valve body 19 of the regeneration air valve 17, it is provided according to the invention that the regeneration air valve 17 is opened as required without regeneration of the particle filter 13 being carried out here.

Such a temporary opening of the regeneration air valve 17 may be performed during non-operation of the combustion engine 1, for example with every stop operation of the internal combustion engine (ausserderettiebnahme) or with a stop operation according to a defined number of previous stop operations or according to a defined minimum operation duration of the internal combustion engine.

The temporary opening of the regeneration air valve 17 for condensate removal can also take place during operation of the combustion engine 1. However, the addition of exhaust gas for post-oxidation combustion of hydrocarbons before the particle filter 13 is not carried out here, since the particle filter 13 should not be regenerated. Such opening of the regeneration air valve 17 can be carried out in particular during coasting of the combustion engine 1, since it can then be excluded that the amount of air introduced into the exhaust system via the regeneration air line 15 which is then opened negatively affects the operating behavior of the internal combustion engine.

According to fig. 2, which shows the orientation of the regeneration air system 14 when integrated into an internal combustion engine or into a motor vehicle (when the motor vehicle is horizontal), the section of the regeneration air line 15 which extends from the regeneration air valve 17 up to the connection 20 (which forms the inlet of the regeneration air line 15 into the exhaust system 10) is formed continuously downward. This ensures that the condensate which has accumulated in the region of the valve body 19 of the regeneration air valve 17 is already introduced into the exhaust system 10 by gravity drive with the regeneration air valve 17 open. Accordingly, no simultaneous operation of the regeneration air delivery device 16 (which would support such withdrawal of condensate) may occur.

Preferably, however, the regeneration air supply device 16 is operated during the opening of the regeneration air valve 17 to support the draining of condensate. This at least plays a role if such an opening of the regeneration air valve 17 is carried out during operation of the combustion engine 1, since then the noise emission of the regeneration air delivery device 16 is drowned in the operating noise of the internal combustion engine or of the motor vehicle comprising it.

According to fig. 3, the regeneration air valve 17 can be configured in the form of a butterfly valve (televentil) with a construction type known in principle. It comprises a housing 21, which forms an intake passage 22 and an exhaust passage 23, which in turn forms a section of the regeneration air line 15. In the transition between the inlet duct 22 and the outlet duct 23, a disk-shaped valve body 19 is arranged, which can be moved by means of a control rod 25, which is part of an electromechanical linear actuator 24. By means of a return spring 26 integrated into the linear actuator 24, the valve body 19 is pressed against a valve seat formed by a sealing ring 27. By active actuation of the linear actuator 24, the valve body 19 can be lifted off the valve seat and thus open the connection between the inlet port 22 and the outlet port 23.

List of reference numerals

1 Combustion Engine

2 cylinder

3 reciprocating piston

4 combustion chamber

5 fresh gas system

6 ambient air inlet

7 air filter

8 fresh gas compressor

9 exhaust gas turbine

10 exhaust system

11 exhaust gas post-treatment device

12 catalytic converter

13 particulate filter

14 regenerative air system

15 regenerative air circuit

16 regenerative air delivery device

17 regenerative air valve

18 control device

19 valve body of regeneration air valve

20 connecting piece

21 casing of regeneration air valve

22 air inlet of regeneration air valve

23 exhaust passage of regeneration air valve

Linear actuator for 24-regeneration air valve

25 stick of linear actuator

26 reset spring of regeneration air valve

27 regenerate the sealing ring of the air valve.