DE102017119260A1 - Charging device, turbocharger and method for charging an internal combustion engine - Google Patents

Abstract

A charging device for charging an internal combustion engine comprises a compressor 31 for compressing charge air for the internal combustion engine, and an atomizer arranged upstream of the atomizer 8 for the non-contact atomization of dispersed in the charge air moisture droplets.

Description

TECHNICAL AREA

The present invention relates to the field of supercharging devices for internal combustion engines, in particular turbochargers. It relates to a charging device with a compressor for charging an internal combustion engine.

STATE OF THE ART

Charging devices, in particular mechanical charging devices and turbochargers, for internal combustion engines, in particular piston engines, serve to increase the power of the engine by pre-compressing the supplied air and to reduce the fuel consumption of the engine.

Turbochargers, which are also referred to as exhaust gas turbocharger, are generally constructed of a compressor and an exhaust gas turbine, which are mechanically connected to each other via a common shaft. Exhaust gases of the internal combustion engine (the piston engine) are supplied to the exhaust gas turbine. Since these exhaust gases are expanded incompletely, a part of the remaining energy of the exhaust gas is converted into rotational energy of the exhaust gas turbine. The rotational energy of the exhaust gas turbine is transmitted via the shaft to the compressor, which compresses the charge air supplied to the piston engine. Thus, the piston engine can be charged with significantly more air, which leads to an increase in efficiency of the piston engine.

In a two-stage turbocharger, two stages are connected in series. 1 shows a schematic representation of a two-stage turbocharger with a connected piston engine from the prior art. A piston engine 1 is with a two-stage turbocharger 2 via a fresh air line 5 and an exhaust pipe 6 connected. The two-stage turbocharger 2 has a low pressure stage and a high pressure stage, each stage each having a simple turbocharger with a compressor 31 . 41 , an exhaust gas turbine 32 . 42 and a common wave 33 . 43 having. Aspirated fresh air first flows through the compressor 31 the low-pressure stage and is thus compressed. The compressed fresh air then flows through the compressor 41 the high-pressure stage and is thus further compressed. The twice compressed fresh air then flows into the piston engine 1 , After combustion in the piston engine 1 the exhaust gas flows through the exhaust gas turbine 42 the high-pressure stage and is partially expanded there. The resulting rotational energy is transmitted through the shaft 43 the high-pressure stage on the compressor 41 transferred to the high-pressure stage. After the exhaust gas turbine 42 the high-pressure stage flows the partially expanded exhaust gas through the exhaust gas turbine 32 the low-pressure stage and will continue to expand there. The resulting rotational energy is transmitted through the shaft 33 the low-pressure stage on the compressor 31 transferred to the low pressure stage.

During compression in the low-pressure stage, not only the pressure, but also the temperature of the fresh air is increased. As a result of this temperature increase, the density of the fresh air decreases as it enters the compressor 41 the high pressure stage, which means that a larger compressor for the high pressure stage must be used. The required power for a given compression ratio thus increases. Therefore, optionally, the fresh air between the compressor 31 the low pressure stage and the compressor 41 the high-pressure stage via an intermediate cooling 7 be cooled. So will the density of the compressor 41 the fresh air supplied to the high-pressure stage is increased so as to enable a smaller compressor and a lower required power in the high-pressure stage.

The efficiency of such a multi-stage turbocharger system, as discussed above, is highly dependent on the temperature of the intermediate cooling. The problem is that the relative humidity of the fresh air increases due to the intercooling. This can be below the dew point, which leads to the formation of water droplets in the air flow. These water droplets impinge on the compressor of the high-pressure stage at high relative speed and, due to the incompressibility of the water and due to the high momentum of the water droplets, can lead to drop erosion on the compressor blades of the high-pressure stage. Thus, the drops of water on the compressor can lead to dripping, which can result in a drop erosion.

These problems are particularly pronounced in two-stage and multi-stage turbochargers with intercooling. However, the problem of water droplets is not limited to these cases. In other cases, condensing, in the charge air dispersed (floating) liquid droplets in the charging device can lead to problems such as drop impact. Another example is the recirculation of exhaust gases, which can also lead to the formation of dispersed droplets due to their high moisture content, as well as any type of cooling of the charge air.

Even after compression and when entering the piston engine, the liquid droplets can lead to problems. For example, the liquid droplets may interact with the lubricating oil for the reciprocating engine and then lead to piston seizure.

A well-known solution to this problem with multi-stage turbochargers with intermediate cooling is to design the intermediate cooling so that the air does not fall below the dew point. When designing a certain security must be taken into account so that the permissible relative humidity must be kept well below 100 percent. This means that the efficiency-enhancing cooling down is significantly limited and thereby the overall efficiency of the turbocharger is limited.

To solve this problem is off DE 102013106820 A1 It is known to extract the water drops from the air before entering the compressor with the aid of a dehumidifying device and to discharge them to the outside. In this way, the air can then be fed into the compressor in a more cooled manner, without causing drop erosion. By removing the condensed water droplets, however, the air is a mass flow and, in the case of a multi-stage turbocharger, a part of the previously performed by the compressor of the low-pressure stage work withdrawn.

PRESENTATION OF THE INVENTION

The object of the present invention is to at least limit the problems associated with the drops of liquid, and at the same time to reduce the disadvantages of the solutions described above.

This object is achieved by the device and the method having the features of the independent claims. Preferred embodiments are subject of the dependent claims.

According to one aspect of the invention, a charging device for charging an internal combustion engine is provided. The charging device comprises a compressor for compressing charge air for the internal combustion engine, and an atomizer arranged upstream of the compressor for non-contact atomization of liquid droplets dispersed in the charge air.

According to another aspect of the invention, a method for charging an internal combustion engine is provided. The method comprises: supplying charge air to an atomizer; Non-contact atomization, through the atomizer, of liquid droplets dispersed in the charge air; Compressing, through a compressor, the charge air with the atomized liquid drops; and supplying the compressed charge air to the internal combustion engine.

As used herein, the terms "upstream, downstream" are to be understood as indicating the direction with respect to the flow direction of the charge air along a charge air line (or turbine side with respect to the flow direction of the exhaust gas along an exhaust gas line).

As charge air, any gas or gas component to be supplied to the internal combustion engine is to be considered before or after the compression or partial compression. Charge air thus includes any charge, partially charged, partially charged and / or charged gas. Typically, the charge air is fresh air. In an exhaust gas recirculation line, the fresh air can also be admixed with exhaust gas. Also, the exhaust gas to be supplied or supplied to the compressor (after the branching from the exhaust main line, but also before mixing with fresh air) is to be regarded as charge air.

The inventors have found that the problems associated with the liquid drops (e.g., drop erosion, piston eaters) are highly dependent on the size of the liquid drops and are primarily caused by large liquid drops. On the other hand, small drops of liquid do not have sufficient momentum to cause drop erosion or to displace enough oil for a piston eater. Therefore, the described problems can be alleviated or greatly reduced even with size reduction of the liquid droplets even if the total amount of air dispersed in the air is not reduced and / or the number of liquid droplets corresponding to the size reduction is considerably increased. This size reduction is achieved by the atomizer, which atomizes the liquid droplets dispersed in the charge air in a contactless manner. The fact that the atomized (reduced size) liquid droplets pose no great risk, for example, a greater cooling of the charge air is made possible, without causing the described erosion damage on the compressor wheel. The greater cooling may result in increased overall efficiency of the turbocharger.

Furthermore, it is not necessary to dissipate accumulating water via a water drain to the outside.

list of figures

• 1 eine Brennkraftmaschine mit einer vorbekannten Aufladungsvorrichtung;
• 2 eine Brennkraftmaschine mit einer Aufladungsvorrichtung gemäß einer ersten Ausführungsform der Erfindung;
• 3 eine Brennkraftmaschine mit einer Aufladungsvorrichtung gemäß einer zweiten Ausführungsform der Erfindung;
• 4 eine Brennkraftmaschine mit einer Aufladungsvorrichtung gemäß einer dritten Ausführungsform der Erfindung;
• 5 eine Brennkraftmaschine mit einer Aufladungsvorrichtung gemäß einer vierten Ausführungsform der Erfindung; und
• 6 einen berührungslosen Zerstäuber für eine Aufladungsvorrichtung gemäß einer Ausführungsform der Erfindung.

The invention will be explained in more detail by means of exemplary embodiments in conjunction with the figures. The figures show in a schematic representation:

• 1 an internal combustion engine with a prior art charging device;
• 2 an internal combustion engine with a charging device according to a first embodiment of the invention;
• 3 an internal combustion engine with a charging device according to a second embodiment of the invention;
• 4 an internal combustion engine with a charging device according to a third embodiment of the invention;
• 5 an internal combustion engine with a charging device according to a fourth embodiment of the invention; and
• 6 a non-contact atomizer for a charging device according to an embodiment of the invention.

The reference numerals used in the drawings are summarized in the list of reference numerals. Basically, the same parts are provided with the same reference numerals.

WAYS FOR CARRYING OUT THE INVENTION

2 shows a schematic representation of an internal combustion engine with a charging device 2 according to a first embodiment of the invention and one with a piston machine connected thereto 1 ,

The charging device 2 includes a turbocharger 3 with a compressor 31 , an exhaust gas turbine 32 and a common wave 33 , Sucked charge air (fresh air) first flows through the compressor 31 and is so condensed. The compressed charge air then flows into the piston engine 1 , After combustion in the piston engine 1 the exhaust gas flows through the exhaust gas turbine 32 and is expanding there. The resulting rotational energy is transmitted through the shaft 33 on the compressor 31 transfer.

Furthermore, the charging device comprises 2 a cooling device 7 for cooling the charge air upstream of the compressor 31 , By cooling, as already possible 1 described, the density of the charge air can be increased, so as to allow a smaller compressor and a lower required power in the high-pressure stage. This advantage is also achieved in a single-stage turbocharger without upstream low-pressure stage. At the same time the cooling leads, as already to 1 described problems in and after the compressor to a condensation of liquid droplets and caused by the liquid droplets dispersed in the charge air 31 such as drop erosion and / or seizure.

To alleviate these problems is along the charge air line between the cooling device 7 and the compressor 31 (ie downstream of the cooling device 7 and upstream of the compressor 31 ) a nebulizer 8th arranged. The atomizer 8th is designed to atomize the liquid droplets dispersed in the charge air.

Through the non-contact atomizing reduces the atomizer 8th the size of when reaching the compressor 31 in the charge air dispersed liquid droplets. In this way, the above-described problems caused by the liquid drops are alleviated. As a result, fewer restrictions must be placed on the cooling performance of the cooling device 7 and thus be taken into account in the efficiency of the charging device.

6 shows an exemplary non-contact atomizer 8th according to an embodiment of the invention, as it is for example in the embodiment of 1 can be used. The atomizer 8th is at the flow channel (the charge air line) 9 upstream of the compressor 31 arranged.

The atomizer 8th is an ultrasonic atomizer and includes an emitter 81 and a reflector 82 for ultrasonic waves. The emitter 81 and the reflector 82 are transverse to the flow direction (arrow left in 6 ) on opposite sides of the flow channel 9 arranged to a transversely to the flow direction extending ultrasonic field 83 in the charge air inside the flow channel 9 to generate. The ultrasound field 83 includes transversely to the flow direction extending ultrasonic waves whose amplitude is schematically as a wave 832 is shown and the wavelength as 833 is designated.

The ultrasound field 83 covers the entire flow cross-section in the image plane 91 of the flow channel 9 and extends in one length 831 along the flow channel 9 , The wavelength 833 is smaller than the flow cross section 91 , The frequency and amplitude of the ultrasonic waves is set such that the ultrasonic field 83 traversing liquid drops 92 be atomized (are crushed by the pressure differences and shear forces in several size-reduced droplets).

The atomizer 8th thus atomizes the liquid drops 92 non-contact, so that the atomizing effect in particular already in the charge air dispersed liquid droplets 92 achieved without direct contact. The atomizer 8th can thus be arranged separately from the cooling device, so that the length 831 of the ultrasonic field does not cover the cooling device.

The atomizer 8th can from the outside on the charge air line 9 act and therefore requires no fundamental modification of the charge air line. It is therefore possible that a new turbocharger in 2 Having shown structure, as well as the retrofitting of an existing turbocharger by the subsequent installation of the atomizer 8th ,

The atomizer is not on the embodiment of 6 but may also include other arrangements of (eg multi-pole) emitters and reflectors for ultrasonic waves that allow for more complex field geometries of the ultrasonic field. Also multi-stage atomizers are possible, such as with different ultrasonic fields of several different wavelengths. Also, the non-contact sputtering effect can be achieved in other ways than by ultrasound, such as by blowing compressed air.

3 shows a schematic representation of an internal combustion engine with a charging device 2 according to a second embodiment of the invention. In addition to 2 is the charger 2 shown as a two-stage turbocharger: the two-stage turbocharger 2 has a low pressure stage 3 and a high pressure stage 4 up, analogous to 1 Each stage has a single turbocharger with a compressor 31 . 41 , an exhaust gas turbine 32 . 42 and a common wave 33 . 43 on, and the description of 1 applies in accordance with also for 3 ,

In addition to the 1 the parts shown, the turbocharger one along the charge air line between the cooling device 7 and the compressor 41 the high-pressure stage (downstream of the cooling device 7 and upstream of the compressor 41 ) arranged non-contact atomizer 8th on. The atomizer 8th works analogously as above 2 described and can, for example, according to 6 be designed. The atomizer 8th is at the in 3 shown arrangement particularly effective, since the problem of liquid drops occurs here in a particularly strong extent, as above 1 discussed.

4 and 5 show schematic representations of internal combustion engine with a charging device 2 according to a third or fourth embodiment of the invention. The charging devices 2 correspond (with the differences discussed below) of the first embodiment of 2 , and the discussion of 2 applies to 4 and 5 ,

In addition, the charging device 2 from 4 and 5 an exhaust gas recirculation line 10 on: Part of the combustion in the piston engine 1 resulting exhaust gas is mixed in a known manner as charge air (more precisely, charge air component) with the fresh air sucked in and the compressor 31 fed. In the exhaust gas recirculation line 10 is a cooling device 7 provided to cool the exhaust gas (as charge air or charge air component). Again, the above-described problem of condensation of liquid droplets in the cooled charge air occurs. Therefore, in these embodiments, a non-contact atomizer 8th downstream of the cooling device 7 (between cooler 7 and compressors 31 ) in the exhaust gas recirculation line 10 arranged.

In 4 branches the exhaust gas recirculation line 10 downstream of the exhaust gas turbine 32 from the exhaust pipe, so that through the exhaust gas turbine 32 expanded exhaust gas is recycled.

In 5 branches the exhaust gas recirculation line 10 upstream of the exhaust gas turbine 32 from the exhaust pipe, allowing the exhaust gas at high pressure, without expansion by the exhaust gas turbine 32 , is recycled.

These figures are intended to illustrate that the charging device according to the invention can be used with atomizer arranged upstream of the compressor in many different configurations. Also, other, not shown configurations are possible, such as by the turbocharger stage of 4 . 5 as a high pressure turbocharger stage (analog high pressure stage 4 in 3 ) is used and upstream in the fresh air supply and downstream in the exhaust pipe another low pressure stage 3 analogous to 3 is provided. Also, the cooling device 7 and / or the atomizer 8th be arranged to act on the mixed with the recirculated exhaust gas fresh air.

The invention can also be generalized to several stages. In such a multi-stage turbocharger then several stages are connected in series analogous to the two-stage turbocharger, wherein the atomizer according to the invention (optionally downstream of a cooling device) upstream of one or more of the compressor is provided.

In addition, the principle can be generalized to general forms of charging, wherein the drive of the compressor does not necessarily have to be made via an exhaust gas turbine, but the compressor may for example be driven directly by a piston engine or by an electric motor.

In the following, further aspects of the invention are explained, which can be combined with any further aspects or embodiments. The reference numerals used merely serve to illustrate corresponding features in the figures, but are not intended to limit the respective embodiments.

In one aspect, the charging device comprises a compressor 31 which is fed via a charge air line (fresh air line optionally with exhaust gas recirculation). Upstream of the compressor is a cooling device 7 arranged in the charge air line and the charge air line with the compressor 31 connected such that air in the cooling device 7 Can be cooled before the air in the compressor 31 entry. Next is a non-contact atomizer between the cooling device 7 and the compressor 31 arranged and so on the charge air line with the cooling device 7 and the compressor 31 connected to that from the cooling device 7 escaping air passes through the atomizer before the air enters the compressor 31 entry.

In another aspect, the atomizer 8th an ultrasonic emitter is arranged for emitting ultrasonic waves into the charge air such that the ultrasonic waves disperse the liquid droplets dispersed in the charge air 92 atomize. The atomizer 8th may also include an ultrasonic reflector. The ultrasound emitter and reflector may be arranged to form upstanding ultrasonic waves, preferably transverse to the flow direction of the charge air. The wavelength of the ultrasonic waves is preferably less than 1/2, preferably less than 1/5 of the diameter of the charge air line.

In a further aspect, the charging device has a cooling device 7 for cooling the charge air. The atomizer 8th may be downstream of the cooling device 7 be arranged to be in by the cooling device 7 cooled charge air dispersed liquid drop 92 to atomise. In one aspect, the nebulizer is located immediately (ie without further equipment) downstream of the cooling device and / or immediately upstream of the compressor. In one aspect, the nebulizer is disposed separate from the cooling device. The ultrasonic waves then do not overlap significantly with the cooling device.

In one aspect, the compressor is arranged to provide the compressed charge air without further compression of a piston engine 1 to supply the internal combustion engine.

In another aspect, the charging device is an at least two-stage charging device. The compressor is then a high pressure compressor 41 (Compressor of the high pressure stage), and the charging device further includes an upstream of the high pressure compressor 41 arranged low-pressure compressor 31 (Compressor Biederdruckstufe) for partial compression of the high-pressure compressor 41 supplied charge air. Here, the terms high-pressure compressor, low-pressure compressor to understand relative to each other, so compresses the high-pressure compressor to a higher pressure than the low-pressure compressor.

In another aspect, the atomizer 8th between the low pressure compressor 31 and the high pressure compressor 41 arranged around the liquid droplets dispersed in the partially compressed charge air 92 to atomise.

In a further aspect, the charging device comprises: a fresh air line 5 ; a compressor 31 a low pressure stage 3 ; a compressor 41 a high-pressure stage 4 , which over the fresh air line 5 so with the compressor 31 the low pressure stage 3 connected is that compressed air from the compressor 31 the low pressure stage 3 in the downstream of the compressor with respect to the flow direction of the air 41 the high pressure stage 4 can flow in and the air in the compressor 41 the high pressure stage 4 can be further compressed; and a cooling device (intermediate cooling) 7 which is between the compressor 31 the low pressure stage 3 and the compressor 41 the high pressure stage 4 is arranged and so on the fresh air line 5 with the compressor 31 the low pressure stage 3 and the compressor 41 the high pressure stage 4 connected to that from the compressor 31 the low pressure stage 3 escaping air in the cooler 7 Can be cooled before the air in the compressor 41 the high pressure stage 4 entry. The atomizer 8th can then between the cooler 7 and the compressor 41 the high pressure stage 4 be arranged and so on the fresh air line 5 with the cooling device 7 and the compressor 41 the high pressure stage 4 be connected to that from the cooling device 7 escaping air through the atomizer 8th occurs before the air enters the compressor 41 the high pressure stage 4 entry.

In another aspect, the atomizer 8th a strength, which strength allows a flow of charge air with an absolute pressure of at least 3 bar, preferably 3 to 4 bar.

In another aspect, the charging device includes an exhaust gas recirculation line 10 from an exhaust pipe of the internal combustion engine to the compressor 31 . 41 to an exhaust gas to the compressor 31 . 41 supply. The atomizer 8th can (together with a cooling device or without a cooling device) on the exhaust gas recirculation line 10 be arranged to the liquid droplets dispersed in the exhaust gas 92 to atomise. The atomizer may also be located in the charge air line after (downstream) mixing with fresh air.

According to a further aspect, the cooling device is designed to reduce the charge air to below 60 degrees Celsius, preferably to 20 to 50 Degree Celsius, cool. According to one aspect, the cooling device comprises a heat exchanger through which a cooling medium flows and which is in thermal contact with the charge air. In one aspect, the cooling device leaves the absolute moisture content of the charge air unchanged as opposed to a scavenger.

According to another aspect, the atomizer is arranged to reduce the diameter of the liquid droplets to less than 200 microns, preferably less than 100 microns when sputtering.

In another aspect, the charge air duct is in the area of the atomizer 8th air and water tight and includes in particular no water drainage for condensation.

In another aspect, the charging device is a turbocharger and further includes a turbine driven by exhaust gas of the internal combustion engine 32 . 42 for driving the compressor 31 . 41 ,

In another aspect, an internal combustion engine with a reciprocating engine 1 and any of the charging devices described herein, to provide the charged charge air of the reciprocating engine 1 supply.

According to a further aspect, a method for charging an internal combustion engine is proposed. The method may include the operation of any of the charging devices described herein.

LIST OF REFERENCE NUMBERS

1

piston engine

2

two-stage turbocharger

3

Low pressure stage

31

Compressor of the low-pressure stage

32

Exhaust gas turbine of the low-pressure stage

33

Wave of low pressure stage

4

High pressure stage

41

Compressor of the high pressure stage

42

Exhaust gas turbine of the high-pressure stage

43

Shaft of the high pressure stage

5

Fresh air line

6

exhaust pipe

7

Cooling device / intermediate cooling

8th

Non-contact atomizer / ultrasonic device

81

emitter

82

reflector

83

ultrasonic field

831

Length of the ultrasonic field

832

Amplitude of the ultrasonic field

833

Wavelength of the ultrasonic field

9

flow channel

91

Flow area

92

liquid drops

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

• DE 102013106820 A1 [0010]

Claims (10)

A charging device for charging an internal combustion engine, the charging device comprising a compressor (31, 41) for compressing charge air for the internal combustion engine, characterized by a sprayer (8) arranged upstream of the compressor for non-contact atomization of moisture droplets (92) dispersed in the charge air. Charging device after Claim 1 , characterized in that the atomizer (8) is arranged an ultrasonic emitter for emitting ultrasonic waves into the charge air such that the ultrasonic waves atomize the moisture droplets (92) dispersed in the charge air. Charging device after Claim 1 or 2 characterized in that the charging device further comprises a cooling device (7) for cooling the charge air, and that the atomizer (8) is arranged downstream of the cooling device (7) in order to reduce the moisture drops dispersed in the charge air cooled by the cooling device (7) ( 92) to atomize. Charging device according to any one of the preceding claims, characterized in that the compressor is a high-pressure compressor (41), and the charging device comprises an at least two-stage charging device with a low-pressure compressor (31) arranged at the top of the high-pressure compressor (41) for partial compression of the high-pressure compressor (41) Charge air is, wherein the atomizer (8) between the low pressure compressor (31) and the high pressure compressor (41) is arranged to atomize the dispersed in the partially compressed charge air moisture droplets (92). A charging device according to any one of the preceding claims, characterized in that the charging device comprises an exhaust gas recirculation line (10) from an exhaust line of the internal combustion engine to the compressor (31, 41) for supplying an exhaust gas to the compressor (31, 41), the atomizer ( 8) is disposed on the exhaust gas recirculation line (10) to atomize the moisture drops (92) dispersed in the exhaust gas. A charging device according to any one of the preceding claims, wherein the charging device is a turbocharger and further comprises an engine exhaust driven turbine (32, 42) for driving the compressor (31, 41). Charging device after Claim 6 based on Claim 5 characterized in that the exhaust gas recirculation line (10) branches off the exhaust pipe downstream of the turbine to supply exhaust gas relaxed from the turbine (32) to the atomizer (8) and then to the compressor (31, 41). Charging device after Claim 6 based on Claim 5 characterized in that the exhaust gas recirculation line (10) branches off the exhaust line upstream of the turbine to supply an exhaust gas not yet released from the turbine (32) to the atomizer (8) and then to the compressor (31, 41). Internal combustion engine, characterized in that the internal combustion engine comprises a piston engine (1) and a charging device according to any one of the preceding claims in order to supply the charged charge air to the piston engine (1). A method of charging an internal combustion engine comprising the method Supplying charge air to an atomizer (8); Non-contact sputtering, through the atomizer (8), of moisture droplets (92) dispersed in the charge air; Compressing, by a compressor (31, 41), the charge air with the atomized drops of moisture (92); and Supplying the compressed charge air to the internal combustion engine.

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