DE102016124666A1 - Method for operating an internal combustion engine - Google Patents

Abstract

In summary, the invention relates to a method for operating an internal combustion engine, in which an exhaust gas stream (102) in an exhaust gas cooler (100) through a front in the flow direction of the exhaust gas, high-temperature section (104) of the exhaust gas cooler (100) and one, in the flow direction the exhaust gas rear, low-temperature section (106) of the exhaust gas cooler (100) is passed, - the exhaust gas stream (102) in the high-temperature section (104) is cooled by a high-temperature coolant stream (108), - the exhaust stream (102) is cooled in the low-temperature section (106) by a low-temperature coolant stream (110) separate from the high-temperature coolant stream (108). According to the invention, the low-temperature coolant stream (110) is set to influence the exhaust gas temperature of the exhaust gas stream, in particular for influencing the exhaust gas temperature of the exhaust gas flow at the low-temperature section (106), in particular at the outlet (114) of the exhaust gas flow Low temperature section (106).

Description

The invention relates to a method for operating an internal combustion engine, comprising the steps of: burning a fuel-air mixture in at least one cylinder of an internal combustion engine, carrying out an exhaust gas flow from the at least one cylinder of the internal combustion engine, cooling the exhaust gas stream in an exhaust gas cooling system with an exhaust gas cooler the exhaust gas flow in the exhaust gas cooler is passed through a high-temperature section of the exhaust gas cooler in the flow direction of the exhaust gas and a low-temperature section of the exhaust gas cooler downstream of the exhaust gas, the exhaust gas flow in the high-temperature section is cooled by a high-temperature coolant flow is cooled, the exhaust gas flow in the low-temperature portion by a separate from the high-temperature refrigerant flow low-temperature refrigerant flow.

The invention further relates to an exhaust gas cooling system, a cooling system and an internal combustion engine.

Methods for operating an internal combustion engine, in particular with cooling the exhaust gas flow, are well known. By cooling the exhaust gas of an internal combustion engine, the combustion temperature in the engine and thus emission of nitrogen oxides is reduced, in particular in an exhaust gas recirculation. Also, a reduced exhaust gas temperature reduces the thermal load on engine components.

However, the risk of sooting exhaust-carrying components of the internal combustion engine, in particular of the exhaust gas cooling system, is still problematic. Sooting occurs in particular when the temperature of the exhaust gas falls below a critical value, in particular the condensation temperature, and deposits can form in the cooler as a result of the condensate then forming. Such deposits can lead to partial or complete blockage of the radiator.

One approach, which among other things leads to the reduction of the risk of soiling, is in DE 10 2009 028 354 B4 shown. This relates to a gas supply system for a periphery of an internal combustion engine for guiding gas in the internal combustion engine, comprising: an inflow-side gas supply for supplying gas to the internal combustion engine; a downstream gas discharge with an exhaust aftertreatment system for removing gas from the internal combustion engine; and a first gas version for executing a first partial gas flow from at least one cylinder of a first cylinder group; and a second gas version for executing a second partial gas flow from at least one cylinder of a second cylinder group, wherein in the case of a partial operation of the internal combustion engine, the at least one cylinder of the first cylinder group is designed for operation with injection and the at least one cylinder of the second cylinder group for operation without injection is designed.

Another approach for influencing the exhaust gas temperature and thus, inter alia, reducing the risk of soiling is the premature discharge or diversion of the exhaust gas flow via a bypass. Such an approach is basically in DE 10 2010 043 027 A1 shown. This document discloses an internal combustion engine having an internal combustion engine with an exhaust side and a charging fluid side and a charging system comprising an exhaust gas turbocharger for supercharging the internal combustion engine, with a compressor assembly on the charging fluid side and a turbine assembly on the exhaust side, a compressor whose primary side on the charging fluid side and its secondary side the exhaust side is connected.

US 8,967,126 B2 describes a method of the preamble. The exhaust gas recirculation cooler for an internal combustion engine described therein comprises an outer housing having an inlet and an outlet for an exhaust stream, a first tube bundle and a second tube bundle, each having an inlet and an outlet for coolant, the first tube bundle and the second tube bundle within the outer housing are arranged, so that the exhaust gas flow in succession through the first tube bundle and the second tube bundle; and a bypass passage for conveying the exhaust gas flow from the downstream side of the first tube bundle to the outlet of the outer housing, bypassing the second tube bundle, the bypass passage being disposed within the outer housing between the first tube bundle and the second tube bundle.

The concept is still in need of improvement in terms of an improved process, in particular a simpler, more durable and more economical construction of the process implementing device, in particular the exhaust gas cooling system. In addition, it would be in need of improvement to achieve these advantages regardless of the basic design of the internal combustion engine, in particular regardless of a possibility mentioned above, to turn off individual donor cylinders during operation.

It is therefore desirable to ensure the function of the exhaust gas cooling and thereby the risk of sooting of gas-carrying parts of the Reduce internal combustion engine including peripherals.

At this point, the invention begins, whose task is to provide a method in an improved manner, which ensures improved exhaust gas cooling. In particular, the risk of sooting is to be reduced by improved exhaust gas cooling.

The object is achieved with respect to the method by the invention with a method of the type mentioned, is provided according to the invention that the low-temperature coolant flow is adjusted to influence the exhaust gas temperature of the exhaust stream, in particular for influencing the exhaust gas temperature of the exhaust stream at the low-temperature section, especially at the outlet of the low-temperature section.

The invention is based on the consideration that cooling down an exhaust gas stream of an internal combustion engine below a critical temperature leads to the formation of condensate from the exhaust gas stream. This in turn leads to sooting, in particular to deposits in the exhaust gas cooler and / or gas-conducting components connected to the exhaust gas cooler. Such deposits result in a partial or complete blockage of the exhaust gas flow within the exhaust gas cooler and / or the gas-conducting components connected to the exhaust gas cooler, which in turn can lead to a functional restriction or failure of the exhaust gas cooler and / or the entire internal combustion engine.

Furthermore, the invention is based on the consideration that a diversion of the exhaust gas flow via a valve and a bypass line is still associated with disadvantages. On the one hand, in particular, the high temperature of the exhaust gas flow of up to 750 ° C and the large temperature range of the exhaust gas flow of 250 ° C to 750 ° C is a burden for all gas-carrying components, in particular lines and valves. Switching and diverting the exhaust gas flow therefore requires high material properties and correspondingly high design effort. Likewise, deposits and sooting may occur in such additional, gas-carrying components.

On the other hand, diverting a partial mass flow through a bypass line is associated with the disadvantage that the exhaust gas mass flow is changed and thus repercussions on the working process occur, which in particular affect the efficiency of the working process in an unfavorable manner.

The invention has recognized that the influencing of the temperature of the exhaust gas flow can take place in an improved manner by switching or regulating the coolant. By specifically influencing the coolant flow, in particular via a valve, a throttle or another suitable adjustment means, the cooling power can be continuously adjusted during operation, so that the temperature of the exhaust gas flow, in particular at the outlet of the low-temperature section, can be controlled, in particular practical can be kept constant. In this way, the exhaust gas temperature during operation, regardless of operating and boundary conditions, be kept at a level on which the risk of sooting is advantageously minimized.

The concept preferably provides the basis for an improved functioning exhaust gas cooling. In contrast to the switching or regulation of the exhaust gas flow, the advantage is thereby achieved that the influencing of the temperature of the exhaust gas flow takes place by the regulated setting of a coolant flow. Since the coolant flow compared with the exhaust gas flow has a significantly lower temperature, the above-mentioned disadvantages of a diversion of the exhaust gas flow through valves and bypass lines are avoided. This is due in particular to the fact that the loads due to the lower temperatures and thus the required material requirements for switching and throttle devices are lower.

Furthermore, unfavorable repercussions on the working process and thus in particular an influence on the efficiency are avoided by a constant exhaust gas mass flow.

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept within the scope of the problem and with regard to further advantages.

In particular, it is provided that the exhaust gas temperature of the exhaust gas stream at the low-temperature section, in particular by adjusting the low-temperature coolant flow, is regulated with a control loop. In concrete terms, this means that the low-temperature coolant flow is adjusted continuously or quasi-continuously as a function of the exhaust gas temperature, in particular at predetermined time intervals, in the sense of a control loop. The advantage of this is the continuous or quasi-continuous adjustment of the exhaust gas temperature, and thus the setting of a practically constant temperature level independent of operating and boundary conditions, in particular the internal combustion engine.

Advantageously, it is provided that the exhaust gas temperature of the exhaust gas stream at the low-temperature section is regulated to an exhaust gas outlet temperature which, in particular, does not fall below the condensation temperature of the exhaust gas flow or only to a degree in which no gasification of the exhaust gas occurs. Specifically, this implies that the exhaust gas outlet temperature to be controlled is maintained practically at a constant level, in particular within or above the condensation temperature range of 160 ° C to 180 ° C. This leads in particular to the advantage that sooting of the exhaust gas as a result of condensing exhaust gas constituents is avoided.

Within the scope of a particularly preferred development, it is provided that the setting of the low-temperature coolant flow takes place via a low-temperature coolant adjusting means which is set to an open position or a closed position under standard setting. Specifically, this low-temperature coolant adjusting means may be formed by a throttle, a valve or the like adjusting means, which in the present development switched in a binary manner, that can be placed in a fully open or a fully closed position. Depending on the particular exhaust gas outlet temperature and optionally further operating and boundary conditions can be switched in this way on the basis of the regulation, the low-temperature coolant-adjusting means to achieve a constant as possible course of the exhaust gas outlet temperature.

Advantageously, it is provided that the adjustment of the low-temperature coolant flow via the low-temperature coolant adjusting means and the opening position of the low-temperature coolant adjusting means under rule setting continuously in a continuous or quasi-continuous manner in an open position or a closed position or an intermediate, partially open position is provided. Specifically, this means that an adaptation of the low-temperature coolant flow, in particular for controlling a predetermined exhaust gas outlet temperature, can be carried out continuously or quasi-continuously in a virtually continuous manner. In contrast to a binary circuit of the valve, this results in particular the advantage of a virtually continuous extending open position of the low-temperature coolant-adjusting means and thus a more uniform, in particular less erratic, tracking the actual exhaust gas outlet temperature to the desired value.

Within the scope of a particularly preferred development, it is provided that the exhaust gas stream when entering the high-temperature section has a temperature between 400 ° C. and 700 ° C. This temperature range represents a typical value range for the exhaust gas temperature at the inlet of the exhaust gas cooler at rated power. Of course, a method according to the concept of the invention is also applicable to further, higher or lower, wider or narrower temperature ranges.

In particular, it is provided that the exhaust gas stream has a temperature between 180 ° C and 240 ° C at the exit from the high-temperature section. Also with regard to this temperature, a method according to the concept of the invention is applicable to further, higher or lower, wider or narrower temperature ranges.

Within the scope of a particularly preferred development, it is provided that the exhaust gas stream when exiting the low-temperature section has a temperature between 80 ° C and 240 ° C. Also with regard to this temperature, a method according to the concept of the invention is applicable to further, higher or lower, wider or narrower temperature ranges.

It is advantageously provided that the method further comprises the step of returning the exhaust gas flow into the at least one cylinder of the internal combustion engine via an exhaust gas recirculation path. Specifically, this means that the cooled exhaust gas is partially or completely guided over an exhaust gas recirculation path and is further admixed to a fresh air flow conducted via an air supply path for combustion in the at least one cylinder of the internal combustion engine. This leads to the known advantages of exhaust gas recirculation, in particular the reduction of the emission of nitrogen oxides, which arise during combustion.

Furthermore, the invention leads within the scope of the task on an exhaust gas cooling system. This is designed to carry out the method, with a low-temperature coolant line, which has a low-temperature coolant adjusting means, in particular the adjusting means is formed by a valve, a throttle, or the like adjusting means. Concretely, this means that the exhaust gas cooling system has a low-temperature coolant adjusting means, by means of which the coolant flow can be adjusted.

In particular, the low-temperature coolant adjusting means may be part of a control loop as an actuator, and in this way with a temperature sensor, in particular at the outlet of the low-temperature section, which acts as a measuring element of the control loop, directly or indirectly signal-conducting. In this way, the control loop according to the concept of the invention can be realized in an advantageous manner.

In particular, it is provided that the exhaust gas cooler has a U-construction, wherein in particular the low-temperature section and the high-temperature section are arranged one above the other and the outlet of the high-temperature section is connected to the inlet of the low-temperature section via at least one bend, which is a change in direction of the exhaust gas flow effected by practically 180 ° and in particular inlet of the high-temperature section and outlet of the low-temperature section are arranged on one side. In concrete terms, this means that the low-temperature section and the high-temperature section are arranged in a compact manner, in particular in a housing. This leads in particular to an advantageous reduction of the required installation space.

Advantageously, it is provided that at least one heat exchanger of the exhaust gas cooler works according to the crossflow principle, in particular the at least one coolant stream and the at least one exhaust gas stream flow in a crossing manner relative to one another. Specifically, this means that the at least one heat exchanger of the exhaust gas cooling system is constructed in such a way that tube bundles or the like coolant-carrying conduit systems extend in a plane perpendicular to the flow direction of the exhaust gas flow. This leads to the advantage that, in contrast to, for example, a countercurrent or DC arrangement, the exhaust gas flow can be brought to a certain temperature in an improved manner.

In particular, it is provided that the exhaust gas cooling system consists of at least two, in particular in the flow direction of the exhaust gas juxtaposed exhaust gas cooler. Specifically, this may mean that the exhaust gas cooling system consists of several exhaust gas coolers, which are arranged side by side in the flow direction of the exhaust gas. Such an arrangement has the consequence in particular in a cross-flow principle that the coolant lines are arranged virtually in alignment and can be connected in this way in a simple and advantageous manner one behind the other. The individual exhaust gas cooler can be arranged in this development, either within an entire outer housing, or in each case have individual outer housing, which are modularly connected to each other.

It is advantageously provided that the exhaust gas cooling system has a first exhaust gas cooler and a second exhaust gas cooler and the first exhaust gas cooler has a first high-temperature section and a first low-temperature section and the second exhaust gas cooler has a second high-temperature section and a second low-temperature section. In this development, two exhaust gas coolers, which in turn are each constructed in two stages in accordance with the concept of the invention, are also advantageously combined in an exhaust gas cooling system. In this case, each exhaust gas cooler each has a low-temperature section and a high-temperature section, wherein in particular the low-temperature coolant flow for influencing the exhaust gas temperature of the exhaust gas flow can be adjusted. Of course, it is analogously possible to combine a larger number of exhaust gas coolers, each of which, as described, constructed according to the concept of the invention.

Furthermore, within the scope of the task, the invention leads to an internal combustion engine, comprising an internal combustion engine with at least one cylinder, an exhaust gas cooling system, designed to carry out the method. Within the scope of the task, the invention also relates to a cooling system for an internal combustion engine.

In a particularly preferred embodiment, an internal combustion engine is provided with gas line and heat exchanger with a high-temperature section and a low-temperature section, wherein the high-temperature section, a high-temperature coolant circuit for cooling the exhaust gas flow in the high-temperature section is connected and a low-temperature coolant circuit for cooling the gas flow, in particular exhaust gas flow and / or charge air flow, is connected to the low-temperature section in the low-temperature section, and wherein the low-temperature coolant circuit and / or the high-temperature coolant circuit is a first and / or second adjustable throttle means for influencing the exhaust gas temperature of the exhaust gas flow in the high-temperature section and / or low-temperature section during operation.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, fall within the scope of the invention, all combinations of at least two in the description, the drawing and / or the Claims disclosed features. The general idea of the invention is not limited to the exact form or detail of the preferred embodiments shown and described below or limited to an article which would be limited in comparison with the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

• 1 eine schematische Darstellung einer Brennkraftmaschine mit einem Abgaskühlsystem gemäß dem Konzept der Erfindung,
• 2 eine besonders bevorzugte Ausführungsform eines Abgaskühlsystems gemäß dem Konzept der Erfindung.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

• 1 a schematic representation of an internal combustion engine with an exhaust gas cooling system according to the concept of the invention,
• 2 a particularly preferred embodiment of an exhaust gas cooling system according to the concept of the invention.

1 shows a schematic representation of an internal combustion engine 400 with an exhaust gas cooling system 1000 according to the concept of the invention. The internal combustion engine 400 also has an internal combustion engine 420 with charging fluid manifold 422 and exhaust manifold 424 on, as well as a compressor arrangement 460 and a turbocharger assembly 440 with low pressure stage 442 and high pressure stage 444 ,

The exhaust gas cooling taking place in the context of exhaust gas recirculation is described in more detail below. The engine 420 over the exhaust manifold 424 leaving exhaust gas flow 102 will be over the inlet 112 first in a conventional, single-stage high-temperature exhaust gas cooler 430 directed. The exhaust gas flow 102 is then in a through a first throttle 111 certain amount by means of the high-temperature exhaust gas cooler 430 pre-cooled and then - depending on the operating condition of the internal combustion engine - supplied in a determined by a second throttle 113 amount of a low-temperature exhaust gas cooler for further cooling - the low-temperature exhaust gas cooler is designed according to the concept of the invention and is hereinafter referred to as exhaust gas cooler 100 by way of example for explaining the concept of the invention.

However, it is possible that in an alternative, not shown embodiment without high-temperature exhaust gas cooler 430 and without first throttle 111 the exhaust gas flow 102 directly via a second throttle in an exhaust gas cooler 100 which is designed according to the concept of the invention.

In the exhaust gas cooler, the exhaust gas flow 102 continue into a high-temperature section 104 of the exhaust gas cooler 100 directed where the exhaust stream 102 by means of a high temperature coolant flow 108 is cooled. From there the exhaust gas flow arrives 102 via a manifold 120 or other comparable, fluid-carrying connecting line in the low-temperature section 106 , In the low temperature section 106 becomes the exhaust gas flow 102 by means of a low-temperature coolant flow 110 further cooled, wherein flow rate of the low-temperature coolant flow 110 and thus the cooling capacity of the low-temperature section 106 via a low temperature coolant adjuster 116 influenced according to the concept of the invention, in particular can be regulated. Finally, the exhaust gas reaches the outlet 114 of the low temperature section 106 where a temperature sensor 122 is arranged to measure the temperature of the exhaust stream. The measured temperature serves in particular as an input variable for a control circuit for controlling the exhaust gas temperature, in particular the exhaust gas outlet temperature, in which in particular the low-temperature coolant adjusting means 116 serves as an actuator.

2 shows in a particularly preferred embodiment, an exhaust gas cooling system 1000 , In the present form, the exhaust gas cooling system 1000 two side by side arranged exhaust gas cooler 100 and 100 ' on. In particular, both exhaust gas coolers each have a high-temperature section 104 . 104 ' , a low-temperature section 106 . 106 ' and a manifold 120 . 120 ' on. It would also be possible for the exhaust gas cooling system 1000 only an exhaust gas cooler 100 or having a larger number of exhaust gas coolers. As in this development, the two exhaust gas cooler 100 and 100 ' are substantially identical, is for simplicity, only one exhaust gas cooler 100 directed.

The exhaust gas cooling system 1000 is formed in this development such that an exhaust gas flow 102 via at least one inlet 112 the at least one high-temperature section 104 in the at least one exhaust gas cooler 100 arrives. In the flow direction, the exhaust gas flow moves 102 through the high-temperature section 104 up to the inlet 112 opposite side of the exhaust gas cooling system 1000 , At this the inlet 112 opposite side closes a manifold 120 the high temperature section 104 at. About this manifold 120 becomes the flow direction of the exhaust gas flow 102 deflected by 180 ° and thus the exhaust gas flow 102 in the below the high temperature section 104 lying low-temperature section 106 directed. Through the connection of High temperature section 104 and low temperature section 106 through the manifold 120 creates a U-construction of the exhaust gas cooler 100 and thus the exhaust gas cooling system 1000 ,

After passing the low-temperature section 106 reaches the exhaust stream 102 the outlet 114 of the low temperature section 106 on the turn of the manifold 120 opposite side of the exhaust gas cooling system 1000 , This is also the side of the exhaust gas cooling system 1000 , which also includes the inlet 112 of the high temperature section 104 located. Due to the U-construction of the exhaust gas cooling system 1000 conditioned, located in this development, the outlet 114 of the low temperature section 106 below the inlet 112 of the high temperature section 104 , on the same, the manifold 120 opposite, outside of the exhaust gas cooling system 1000 ,

The cooling of the exhaust gas flow 102 takes place in the present development according to the principle of a heat exchanger with cross-flow principle. For this purpose, perpendicular to the flow direction of the exhaust stream 102 , a high-temperature coolant flow 108 in the high-temperature section 104 directed. This flows through, in particular within pipelines or tube bundles, which within the high-temperature section 104 are arranged, the from the exhaust stream 102 passed area. In this way, according to the well-known principle of a heat exchanger, an exchange of heat, in particular a release of heat of the exhaust gas stream 102 to the high temperature coolant flow 108 , instead of.

Analogous to this also takes place in the low-temperature section 106 An exchange of heat takes place by a low-temperature coolant flow 110 , perpendicular to the flow direction of the exhaust stream 102 , in the low-temperature section 106 is directed. The low temperature coolant flow 110 is here by a low-temperature coolant adjusting means 116 influenced. In particular, can be by the low-temperature coolant-adjusting 116 the flow rate of the coolant for regulating the cooling effect of the low-temperature section 106 influence. By throttling the low-temperature coolant flow 110 the flow rate of the refrigerant is reduced, resulting in a reduction in the cooling performance of the low-temperature section 106 leads. Conversely, through an opening of the low temperature coolant adjusting means 116 the flow rate of the low-temperature coolant flow 110 are increased, which accordingly leads to an increase in cooling capacity.

The low temperature coolant adjuster 116 is as part of a control circuit shown schematically here 118 with a temperature sensor 122 signal-conducting connected. The temperature sensor 122 is in this development in the area of the outlet 114 of the low temperature section 106 arranged. By such an arrangement, the exhaust gas temperature in the region of the outlet 114 be measured and in the case of a deviation of the exhaust gas temperature from a predetermined target temperature of the low-temperature coolant flow 110 be influenced by the low-temperature coolant adjusting means 116 accordingly.

In the simplest case, this means that when the setpoint temperature is exceeded by a further opening of the low-temperature coolant adjusting means 116 the flow rate of the low-temperature coolant flow 110 and thus the cooling capacity of the low-temperature section 106 is increased, which has a lowering of the exhaust gas temperature and thus an approximation to the target temperature result. Conversely, if the setpoint temperature is undershot, further closure of the low-temperature coolant adjuster would occur 116 a reduction in the flow rate of the low-temperature coolant flow 110 and thus also a reduction in the cooling capacity of the low-temperature section 106 have as a consequence. In this way, an increase of the exhaust gas temperature and thus in turn an approximation to the target temperature would take place.

LIST OF REFERENCE NUMBERS

100, 100 '

exhaust gas cooler

102

exhaust gas flow

104, 104 '

High temperature section of the exhaust gas cooler

106, 106 '

Low-temperature section of the exhaust gas cooler

108

High temperature coolant flow, high temperature coolant circuit

110

Low temperature coolant flow, low temperature coolant circuit

111

first throttle

112

Inlet of the high-temperature section

113

second throttle

114

Outlet of the low-temperature section

116

Low temperature coolant adjusting means, valve or the like throttle means for coolant

118

loop

120, 120 '

elbow

122

temperature sensor

400

Internal combustion engine

420

Internal combustion engine

422

Ladefluidkrümmer

424

exhaust manifold

430

High-temperature exhaust gas cooler

440

turbocharger assembly

442

Low pressure stage

444

High pressure stage

460

compressor assembly

1000

Exhaust gas cooling system

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 102009028354 B4 [0005]
• DE 102010043027 A1 [0006]
• US 8967126 B2 [0007]

Claims (17)

A method of operating an internal combustion engine, comprising the steps of: - combusting a fuel-air mixture in at least one cylinder of an internal combustion engine, - carrying an exhaust gas stream (102) from the at least one cylinder of the internal combustion engine, - cooling the exhaust gas stream in an exhaust gas cooling system (1000) with an exhaust gas cooler (100), wherein - the exhaust gas flow (102) in the exhaust gas cooler (100) through a, upstream in the flow direction of the exhaust gas, high-temperature section (104) of the exhaust gas cooler (100) and a, in the flow direction of the exhaust gas, low temperature Portion (106) of the exhaust gas cooler (100) is passed, - the exhaust gas stream (102) in the high-temperature section (104) is cooled by a high-temperature coolant stream (108), - the exhaust gas stream (102) in the low-temperature section (106) is cooled by a low temperature coolant stream (110) separate from the high temperature coolant stream (108), characterized in that - The low-temperature coolant stream (110) is set to influence the exhaust gas temperature of the exhaust gas stream, - in particular for influencing the exhaust gas temperature of the exhaust gas stream at the low-temperature section (106), in particular at the outlet (114) of the low-temperature section (106). Method for operating an internal combustion engine after Claim 1 Characterized in that the exhaust temperature of the exhaust gas stream at the low temperature portion (106), in particular by adjusting the low temperature coolant stream (110) with a control circuit (118) is controlled. Method for operating an internal combustion engine after Claim 2 , characterized in that the exhaust gas temperature of the exhaust gas stream at the low-temperature portion (106) is controlled to an exhaust gas outlet temperature, which in particular the condensation temperature of the exhaust gas flow is not or only to a degree in which no fuming of the exhaust gas, falls below. Method for operating an internal combustion engine according to one of the preceding claims, characterized in that the setting of the low-temperature coolant flow 110 via a low-temperature coolant adjusting means (116), which is set under control default in an open position or a closed position. A method of operating an internal combustion engine according to any one of the preceding claims, characterized in that the setting of the low-temperature coolant flow (110) via the low-temperature coolant adjusting means (116) and the opening position of the low-temperature coolant adjusting means (116) under rule setting stepless is placed in a continuous or quasi-continuous manner in an open position or a closed position or an intermediate, partially opened position. Method for operating an internal combustion engine according to one of the preceding claims, characterized in that the exhaust gas stream when entering the high-temperature section (104) has a temperature between 400 ° C and 700 ° C. Method for operating an internal combustion engine according to one of the preceding claims, characterized in that the exhaust gas stream at exit from the high-temperature section (104) has a temperature between 180 ° C and 240 ° C. Method for operating an internal combustion engine according to one of the preceding claims, characterized in that the exhaust gas stream exiting the low-temperature section (106) has a temperature between 80 ° C and 240 ° C. Method for operating an internal combustion engine according to one of the preceding claims, characterized in that the method further comprises the step of: - returning the exhaust gas stream (102) in the at least one cylinder of the internal combustion engine via an exhaust gas recirculation path. Exhaust gas cooling system (1000), designed to carry out the method according to one of the preceding claims, with - An exhaust gas cooler (100), wherein the exhaust gas flow (102) in the exhaust gas cooler (100) through a high-temperature section (104) of the exhaust gas cooler (100) in the flow direction of the exhaust gas and a low-temperature section (106) of the exhaust gas cooler downstream of the exhaust gas ( 100), the exhaust gas stream (102) in the high-temperature section (104) is cooled by a high-temperature coolant stream (108), the exhaust gas stream (102) in the low-temperature section (106) is cooled by a low-temperature coolant stream (110) separate from the high-temperature coolant stream (108), - A low-temperature coolant line having a low-temperature coolant adjusting means (116), in particular the adjusting means by a valve, a throttle, or the like adjusting means is formed, in particular for influencing the exhaust gas temperature of the exhaust gas stream at the low-temperature portion (106), in particular at the outlet (114) of the low temperature section (106). Exhaust gas cooling system (1000) after Claim 10 characterized in that the exhaust gas cooler (100) has a U-construction, wherein in particular low-temperature section (106) and high-temperature section (104) arranged one above the other and the outlet (114) of the high-temperature section (104) with the inlet of Low-temperature section (106) via at least one manifold (120) is connected, which causes a change in direction of the exhaust gas flow by practically 180 °, and in particular inlet (112) of the high-temperature section (104) and outlet (114) of the low-temperature section (106 ) are arranged on one side. Exhaust gas cooling system (1000) after Claim 10 or 11 , characterized in that at least one heat exchanger of the exhaust gas cooler (100) works according to the cross-flow principle, in particular the at least one coolant flow (108, 110) and the at least one exhaust gas flow (102) in a crossing manner to each other. Exhaust gas cooling system (1000) according to one of Claims 10 to 12 Characterized in that the exhaust gas cooling system (1000) of at least two, in particular in the flow direction of the exhaust gas juxtaposed exhaust gas coolers (100). Exhaust gas cooling system (1000) according to one of Claims 10 to 13 characterized in that the exhaust gas cooling system comprises a first exhaust gas cooler (100) and a second exhaust gas cooler (100 ') and the first exhaust gas cooler (100) has a first high temperature portion (104) and a first low temperature portion (106) and the second Exhaust gas cooler (100 ') having a second high-temperature section (104') and a second low-temperature section (106 '). Internal combustion engine, comprising an internal combustion engine having at least one cylinder, an exhaust gas cooling system (1000) according to one of Claims 10 to 14 , configured to carry out the method according to one of Claims 1 to 9 , Cooling system for an internal combustion engine with gas line and heat exchanger having a high-temperature section (104) and a low-temperature section (106), wherein the high-temperature section (104) a high-temperature coolant circuit (108) for cooling the exhaust gas flow in High-temperature section is connected and to the low-temperature section, a low-temperature refrigerant circuit (110) for cooling the gas flow, in particular exhaust gas flow (102) and / or charge air in the low-temperature section (106) is connected and wherein the low temperature -Coolant circuit (110) and / or the high-temperature coolant circuit (108) has a first and / or second adjustable throttle means (116) for influencing the exhaust gas temperature of the exhaust stream (102) in the high-temperature section (104) and / or Low temperature section (106) in operation. Internal combustion engine, comprising an internal combustion engine with at least one cylinder and a cooling system of the Claim 16 ,

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