DE112014003726T5 - An arrangement for preventing the cooling of an exhaust treatment component in a vehicle - Google Patents

Abstract

The present invention relates to an arrangement for counteracting the cooling of an exhaust gas component in a vehicle. The arrangement comprises a braking system (11) itself comprising a braking component in the form of a retarder (11a) connected to the drive train of the vehicle, and a first conduit (11c) adapted to move a liquid medium to the retarder (11a). 11a) in operating situations in which the retarder (11a) is activated. The brake system (11) includes a first heat exchanger (11f) for cooling the liquid medium positioned in the exhaust pipe (2) at a point between the engine (1) and the exhaust treatment component (6), and a second pipe (11e) adapted for receiving warm liquid medium from the retarder (11a) and directing it to the first heat exchanger (11f) in operating situations in which the retarder (11a) is activated.

Description

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention relates to an arrangement for preventing the cooling of an exhaust gas component in a vehicle according to the preamble of claim 1.

Exhaust pipes of internal combustion engines, such. As diesel engines, a variety of exhaust treatment components, for. Particulate filter DPF (Diesel Particulate Filter) and SCR (Selective Catalytic Reduction) catalyst. A particulate filter traps soot particles from the exhaust gases, which subsequently burn in a regeneration process. In order to remove nitrogen oxides from the exhaust gases, a urea solution is injected into the exhaust pipe at a point upstream of the SCR catalyst. The urea solution is vaporized by the warm exhaust gases in the exhaust pipe, resulting in the formation of ammonia. The ammonia and the nitrogen oxides in the exhaust gases react with each other in the SCR catalyst, resulting in the formation of nitrogen gas and water vapor. For a SCR catalyst to be highly efficient, it must have a temperature that is above a minimum, which may be on the order of 200 ° C. Nevertheless, the SCR catalyst should not be too high in temperature as its efficiency drops above a certain level, and there is also the risk of damaging the active layers of the catalyst by too hot exhaust gases.

Heavy vehicles are generally provided with a hydrodynamic brake in the form of a hydraulic retarder, which regulates braking on downhill slopes. When a retarder is activated, normally no fuel goes to the engine. In this situation, during the braking process, the engine pumps cold air through the exhaust treatment components into the exhaust system. If the downgrade is long, an SCR catalyst can be cooled well to a lower temperature than required to inject urea solution into the exhaust conduit. In such cases, the catalyst may take a non-negligible period of time to return to temperatures at which the SCR catalyst can reduce the nitrogen oxide content of the exhaust gases in an optimum manner.

The GB 2 058 911 relates to a heat exchanger for cooling oil used in the hydraulic retarder. The heat exchanger is arranged in a bypass line to an inlet line which supplies air to an internal combustion engine. By means of a valve, the intake air can be passed through the bypass line and cool the oil in the heat exchanger before it flows to the engine. The retarder oil can thus undergo cooling, while at the same time the heated intake air will counteract the cooling of the engine, which occurs when the retarder is activated.

The EP 1 547 842 relates to a method for recovering braking energy in a hybrid vehicle powered by an internal combustion engine and an electric motor. During a braking process, the electric motor serves as a generator and generates electrical power that is normally stored in a battery. During a lengthy braking process, a large amount of braking energy is developed. The capacity of the battery will not always be sufficient to store all the electrical power generated during such a braking process. In such cases, the generated electric power is conducted to an electric heater for directly or indirectly heating exhaust gases in an exhaust pipe. Exhaust treatment components in the exhaust pipe may thus undergo heating during the braking process of the hybrid vehicle.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to maintain a desired operating temperature of an exhaust treatment component in an exhaust pipe in operating situations in which a hydraulic retarder is activated in a vehicle.

This object is achieved with the arrangement of the type mentioned in the introduction, which is characterized by the features specified in the characterizing part of claim 1. A liquid medium, which is passed through a hydraulic retarder undergoes a strong warming when the retarder slows down the drive train of the vehicle. The liquid medium is advantageously an oil which has the characteristic that it can be heated to a high temperature without affecting its characteristics. The warm, liquid medium leaving the retarder must be cooled under all circumstances before it can be reused in the retarder. When the retarder is activated, the vehicle is braked by the engine and cold air is pumped through the exhaust conduit, with the consequent risk that exhaust treatment components in the exhaust conduit are cooled to a temperature at which they can not purify the exhaust gases in a desirable manner , The exhaust treatment components must therefore be heated while at the same time the liquid medium in the brake system of the retarder must be cooled. According to the invention, the brake system comprises a first line, the warm liquid medium from the activated retarder to a first heat exchanger, which is positioned in the exhaust pipe at a point upstream of the exhaust gas purification component. The air pumped through the exhaust pipe thus undergoes heating, while at the same time underflows the liquid medium cooling. Thus, the exhaust gas purifying component may maintain a relatively high temperature throughout the period when the retarder is activated and the vehicle is braked by the engine, and may therefore begin to purify the exhaust gases in a substantially optimum manner once the retarder is deactivated and fuel is injected back into the engine.

In one embodiment of the present invention, the exhaust pipe is divided into two parallel pipes in a portion positioned between the engine and the exhaust treatment component, and the first heat exchanger is positioned in one of said parallel pipes. The assembly may include a first flow element configured to distribute the gas flow in the exhaust conduit between the two parallel conduits. That is, all of the exhaust gas flow from the engine can be routed through the parallel conduit which does not have a heat exchanger when the retarder is not activated. The heat exchanger thus does not affect the exhaust gases during operation of the engine. All or part of the airflow, when the retarder is activated and the vehicle is braked by the engine, may be directed through the other parallel line comprising the heat exchanger. Thus, in operating situations where the retarder is activated, air pumped through the exhaust conduit can be heated by the warm liquid medium from the retarder.

In one embodiment of the present invention, the arrangement in the brake system includes a second flow element configured to direct a variable flow of the liquid medium to the heat exchanger. The heat transfer into a heat exchanger is related to the temperatures and flows of the heat exchange media. The air in the exhaust pipe can be heated to a variable temperature z. B. be heated by varying the flow of the liquid medium through the first heat exchanger.

The assembly may include a control unit configured to control the first flow member and / or the second flow member and thus heat transfer into the heat exchanger when the retarder is activated such that the gas directed to the exhaust treatment component has a temperature that is within a range Area is located, in which the exhaust gas purification component has an optimal exhaust gas treatment capacity. Such control allows the exhaust treatment component to maintain an optimal operating temperature throughout the period when the retarder is activated and the vehicle is braked by the engine. The exhaust treatment component will thus have an optimum temperature for treating exhaust gases as soon as the engine braking process ends and exhaust gases begin to flow through the exhaust treatment component again. In this case, a heating period with deficient exhaust purification is eliminated after an engine braking process is completed.

In one embodiment of the present invention, the controller is configured to perform heat transfer control in the heat exchanger based on information from at least one sensor monitoring a parameter related to the temperature of the exhaust treatment component. This is a simple way of providing feedback as to whether the exhaust treatment component has an acceptable temperature. When said sensor indicates that the exhaust treatment component is too low in temperature, the heat transfer in the heat exchanger is adjusted so that the air pumped through the exhaust pipe assumes an elevated temperature. When the sensor indicates that the exhaust treatment component is too high in temperature, the heat transfer in the heat exchanger is adjusted so that the air pumped through the exhaust pipe assumes a lower temperature.

In one embodiment of the present invention, the control unit is adapted to receive information from a sensor monitoring the gas temperatures within the exhaust conduit at a point close to the exhaust treatment component. It is usually inappropriate to incorporate a sensor with an exhaust treatment component to directly monitor the temperature of the exhaust treatment component. Exhaust treatment components have an active surface layer in contact with the gas flowing therethrough, and therefore, will relatively quickly assume substantially the same temperature as the gas. Measuring the gas temperature close to the exhaust treatment component is straightforward and provides a good indication of the temperature of the exhaust treatment component. Other sensors may also be used to control the heating of the air in the heat exchanger. Such sensors can, for. As the air flow in the exhaust pipe, and monitor the temperature and the flow of the liquid medium in the brake system.

In a further embodiment of the present invention, the brake system comprises a second heat exchanger, wherein the liquid medium is cooled. In a conventional braking system, the liquid medium in a heat exchanger is cooled by coolant from the engine's cooling system. In this case, it is also appropriate to use such a heat exchanger to subject the liquid medium to a second step of cooling after undergoing a first step of cooling in the first heat exchanger. The fact that, in this case, the liquid medium is also cooled in two heat exchangers also results in a reduced cooling requirement in the second heat exchanger, and thus the load is on the cooling system of the engine, which is normally subjected to high stresses when it is large Cooling down the amount of thermal energy that can be generated during a lengthy braking process with a hydraulic retarder.

In one embodiment of the invention, the assembly includes a WHR system configured to absorb thermal energy from the gases in the exhaust conduit at a point downstream of the exhaust treatment component. That is, the thermal energy that the air takes up in the first heat exchanger can be recovered and reused, or stored as electric current. The stored electrical current may be used to operate the vehicle or its components on a later occasion. A WHR system allows the exhaust treatment component to be provided in a very energy efficient manner of heating.

In another embodiment of the present invention, the exhaust treatment component is an SCR catalyst. For an SCR catalyst to be able to reduce nitrogen oxides in exhaust gases, a urea solution must be injected into the exhaust pipe at a point upstream of the catalyst and vaporized. The arrangement according to the invention allows an SCR catalyst to maintain a temperature that corresponds to a desired operating temperature during a braking process. The exhaust gases can therefore be provided with urea solution, and undergo optimal reduction of nitrogen oxides in the catalyst immediately after the retarder braking process ceases. The exhaust treatment component need not be an SCR catalyst, but may be essentially any exhaust treatment component in an exhaust pipe that requires a certain temperature to function optimally. Such other exhaust treatment components could be an oxidation catalyst or an ammonia slip catalyst.

In another embodiment of the present invention, the brake system includes flow components configured to direct cooled liquid medium to the heat exchanger and to cool exhaust gases that are directed by the heat exchanger into operating situations in which the retarder is not activated. Exhaust treatment components usually require a relatively high exhaust gas temperature to function in an optimal manner. When the temperature of the exhaust gas becomes too high, the efficiency of the exhaust treatment components usually decreases, while at the same time there is the risk that active surface layers of the exhaust treatment components are damaged by exhaust gases that are too hot. In this case, the heat exchanger and the liquid medium can be used to cool the exhaust gases in operating situations in which the exhaust gases are too hot. This means that the optimum cleaning of the exhaust gases in an exhaust gas treatment component can be achieved even in operating situations with very high exhaust gas temperatures. This also means that the life of the exhaust treatment components is not reduced by damage that can occur through contact with very hot exhaust gases.

In another embodiment of the present invention, the exhaust conduit includes a particulate filter positioned upstream of the SCR catalyst, wherein the first heat exchanger is positioned in the exhaust conduit at a point between the particulate filter and the catalyst. Exhaust gases from diesel engines contain soot particles, so exhaust pipes for diesel engines are provided with a particulate filter, which traps soot particles from the exhaust gases. However, the particulate filter must be regenerated at regular intervals. The regeneration process involves exposing the exhaust gases to such high temperature that the soot particles in the filter burn. This can be achieved by a heavy load on the engine or by injecting unburned fuel into the exhaust pipe. In a regeneration process, it is appropriate to use the liquid medium to cool the exhaust gases in the heat exchanger. An SCR catalyst may thus assume a lower temperature than that prevailing in the particulate filter during the regeneration process. The catalyst can thus maintain optimal reduction of nitrogen oxides during the regeneration process. The cooling of the exhaust gases in the first heat exchanger prevents active surface layers of the catalyst from coming into contact with excessively hot exhaust gases.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described below with reference to FIGS attached drawings, wherein:

1 represents an arrangement according to a first embodiment of the present invention, and

2 an arrangement according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

1 represents an internal combustion engine 1 which is adapted to drive a vehicle. The motor 1 can z. B. be provided to drive a heavy vehicle. The engine is with an exhaust pipe 2 provided, of which only a part is shown. The exhaust pipe may initially be provided with a turbine, not shown, of a turbo unit for compressing intake air supplied to the engine and a return line, not shown, for recirculating exhaust gases. The exhaust pipe comprises a section which is in two parallel lines 2a . 2 B is divided. A valve 3 is provided at a point where the exhaust pipe into two parallel lines 2a . 2 B Splits. The valve, here in the form of a damper 3 by way of example, allows the gas flow in the exhaust conduit to either one of the two parallel conduits 2a . 2 B can be directed. It is also possible to divide the gas flow in a variable manner between the two parallel lines. The parallel lines go at a point upstream of a number of the exhaust gas purification components 4 - 7 together again.

The exhaust gas purification components in this case are an oxidation catalyst 4 , a particle filter 5 , an SCR catalyst 6 and an ammonia slip catalyst 7 , In the oxidation catalyst, part of the nitrogen monoxide in the exhaust gases is oxidized to nitrogen dioxide. Thus, equal ratios of nitrogen dioxide and nitrogen monoxide can therefore be achieved in the exhaust gases. The exhaust gases should preferably contain equal amounts of nitrogen monoxide and nitrogen dioxide when used in the downstream positioned SCR catalyst 6 in order to enable optimal reduction of nitrogen oxides to be achieved. After the oxidation catalyst 4 the exhaust gases become a particulate filter 5 passed, are caught in the soot particles and burned. An injector, not shown, is provided to urea solution into the exhaust passage at a point upstream of the SCR catalyst 6 inject. The urea solution is vaporized by the warm exhaust gases, resulting in the formation of ammonia in the exhaust gases. The exhaust gases must have relatively high temperatures in order to evaporate the ammonia. The ammonia and the nitrogen oxides in the exhaust gases react with each other when they reach the SCR catalyst, resulting in the formation of nitrogen gas and water vapor. In order for the nitrogen oxides in an SCR catalyst to be effectively reduced, they must have a temperature of at least 200 ° C. However, the exhaust gas temperature should never be too high, as the efficiency of the catalyst will fall at too high temperatures, which also carries a greater risk of damaging its active layers. All remaining ammonia in the exhaust gases is in the ammonia slip catalyst 7 eliminated, the downstream of the SCR catalyst 6 is positioned.

The exhaust pipe 2 is at a point downstream of the exhaust treatment components 4 - 7 with a WHR (waste heat recovery) system 8th for recovering thermal energy from the gases in the exhaust pipe. The WHR system 8th includes a closed-loop circuit with a circulating medium, the evaporation and condensation temperatures of which are appropriate for the purpose of pressure occurring in the circuit during operation. The medium can be water. The medium is in the line circuit by a pump 8a circulated. The WHR system includes a heat exchanger in the form of one in the exhaust pipe 2 positioned evaporator 8b , The medium in the evaporator is heated by the gases in the exhaust pipe to a temperature at which it evaporates. The WHR system includes an expander in the form of a turbine 8c in which the medium expands. The turbine is therefore provided with a rotary motion which is a generator 8d can drive to generate electric current in a battery 8e is stored. Alternatively, the rotational movement of the turbine can be converted via a mechanical transmission into a drive movement for the drive train of the vehicle. The WHR system includes a capacitor 8f in which the medium is cooled to a temperature at which it condenses. Of course, the WHR system may also include other components, e.g. B. a recuperator and a heater to ensure that all of the medium evaporates before it is fed to the turbine. A possible alternative is a WHR system that includes a thermoelectric generator.

The motor 1 is set up to power the vehicle via a powertrain. The powertrain includes, among other things, a rotatable shaft 9 and a drive shaft, which is a pair of drive wheels 10 wearing. The vehicle is equipped with a hydrodynamic braking system 11 provided, the one retarder 11a includes. The retarder consists of a stator element which is stationary and a rotor element which engages with the rotatable shaft 9 in the drive train turns. The rotatable shaft may be positioned in a transmission of the vehicle or in the vicinity thereof. The stator element and the rotor element together form an annular space. When the retarder is activated, a liquid medium in the form of retarder oil is passed through the annular space. The stator element and the rotor element are provided in the annular space with blades which, together with the retarder oil, induce a braking process of the rotor element in relation to the stator element, and thus in relation to the drive train and the vehicle. The retarder oil undergoes intense heating as it passes through the annular space during a retarder braking process.

The brake system 11 includes a container 11b for retarder oil. The retarder oil is transferred from the container to the retarder 11a via an inlet pipe 11c passed with a valve 11d is provided, whereby the retarder is activated. When the valve 11d is opened, oil is passed from the container to the annular space of the retarder, whereby the retarder is activated. When the valve 11d is closed, no oil is passed to the retarder, which is therefore not activated. When the retarder is activated, oil from the annular space becomes a first heat exchanger 11f via an outlet pipe 11e directed. The first heat exchanger is in the second parallel line 2 B positioned the exhaust pipe. The warm oil from the retarder undergoes a first step of cooling in the first heat exchanger 11f through gases passing through the second parallel line 2 B flow the exhaust pipe. The oil then becomes a second heat exchanger 11g in which it undergoes a second step of cooling by a coolant circulating in a cooling system that cools the engine. The oil thus reaches the container 11b in a cooled state and can then be reused in the retarder as long as the valve 11b is kept open. A control unit 12 is set up to the valve 11i , and thus to control the activation of the retarder. The brake system 11 includes a first bypass line 11h and a valve 11i , whereby a part of the oil at the first heat exchanger 11f can be bypassed. The control unit is also set up to the valve 11i , and thus to control the flow of oil through the first heat exchanger.

The control unit 12 receives information from a brake control 13 by a driver to activate the retarder 11a is used. The control unit regulates the gas flow through the parallel lines 2a . 2 B by means of the damper 3 , In operating situations in which the retarder is not activated, the damper is located 3 usually in a first position, which is an inlet opening to the second parallel conduit 2 B completely closes, in which case the entire exhaust gas flow through the first parallel line 2a is directed. In operating situations in which the retarder is not activated, the control unit brings the damper 3 in a second position, indicated by a dotted line in 1 is shown, in which the entire exhaust gas flow through the second parallel line 2 B and the first heat exchanger 11f is directed. When the retarder is activated, the engine pumps air through the exhaust pipe 2 , The air is heated by the warm oil from the retarder in the first heat exchanger. The heated air in the first heat exchanger then passes through the exhaust gas treatment components 4 - 7 therethrough. The heated air may be used to prevent the exhaust treatment components from cooling when the retarder is activated. A sensor 14 monitors the gas temperature at a point substantially immediately upstream of the exhaust treatment components.

In operating situations in which the vehicle reaches a long downhill stretch, the driver activates the retarder via the brake control 13 , Alternatively, the retarder can be activated automatically. When the control unit 12 receives this information, the valve opens 11d , whereupon the retarder oil from the container 11b to the retarder 11a over the inlet pipe 11c is pulled. The flow of retarder oil through the retarder causes the vehicle to be braked. The supply of fuel to the engine stops while the retarder is activated at the same time, and the engine stops air through the exhaust pipe 2 inflated. The control unit receives information from the sensor 14 with respect to the gas temperature in the exhaust pipe in the vicinity of the exhaust gas treatment components 4 - 7 , As soon as the gas temperature falls below a lower threshold, the control unit brings the damper 3 in the second position, so that the air in the exhaust pipe through the second parallel line 2 B is directed. The air passes through the retarder oil in the first heat exchanger 11f heated. The sensor 14 monitors the temperature of the air before passing through the exhaust treatment components. The control unit receives information about the temperature of the air substantially continuously from the sensor 14 , If the sensor indicates that the air is too low, the control unit actuates the valve 11i such that the oil flow through the first heat exchanger 11f elevated. If the sensor indicates that the air is too high in temperature, the control unit actuates the valve 11i such that the oil flow through the first heat exchanger 11f reduced. Such control allows the exhaust treatment components 4 - 7 , and in particular the SCR catalyst 6 a temperature within one Range in which the catalyst reaches an optimal oxidation of nitrogen oxides. The warm air leaving the exhaust treatment components is passed through the evaporator 8b in which it vaporizes the medium in the WHR system 8th circulated. The thermal energy with which the air passes through the first heat exchanger 11f can thus also be used in the WHR system and converted into electrical power or mechanical energy. The WHR system can therefore also generate electrical power or mechanical energy at times when the vehicle is being braked with an engine brake.

When the vehicle has reached the end of the hill, the control unit closes 12 the valve 11d so that the flow of oil to the retarder 11a ceases. The injection of fuel into the engine begins, and exhaust gases flow through the exhaust pipe again 2 , The control unit brings the damper 3 in the first position, so that the entire exhaust gas flow through the first parallel line 2a passes. Injection of urea solution begins, and the SCR catalyst can immediately begin to oxidize the exhaust gases in an optimum manner since it will maintain its optimum operating temperature for the time that the retarder was activated. The period of deficient oxidation of nitrogen oxides that may occur when the SCR catalyst is cooled during a retarder braking process is thus eliminated. In addition, the improved exhaust gas cleaning capability provides the retarder oil with a first step of cooling in the first heat exchanger 11f ready. This allows the second heat exchanger 11g has a smaller capacity. It can be made smaller and present a smaller load on the normal cooling system for cooling the engine when the retarder is activated. Alternatively, the retarder may have more braking power.

2 represents an alternative embodiment. The arrangement in this embodiment comprises substantially all components of those in 1 , and a number of other components. It thus has the same capability as the arrangement in 1 on to the air in the exhaust pipe 2 to heat and maintain the temperature of the downstream positioned SCR catalyst when the retarder 11a is activated, so that the catalyst can clean the exhaust gases immediately after the braking process ends. It has a WHR system in a similar way 8th capable of utilizing the thermal energy in the heated air at a point downstream of the exhaust treatment components when the retarder is activated.

However, in this alternative embodiment, the parallel lines are 2a . 2 B between the particle filter 5 and the SCR catalyst 6 positioned. The brake system 11 in this case comprises a second bypass line 11j that is between the inlet pipe 11c and the outlet pipe 11e extends. The brake system includes a three-way valve 11k which can take three different positions, namely a first position that is closed, a second position, the cooled retarder oil from the tank 11b to the retarder 11a directs, and a third position, the cooled retarder oil from the tank to the bypass line 11j passes. A control unit 12 is adapted to bring the three-way valve in the respective positions in different operating situations and the activation of the pump 11m to control.

During operation of the engine, the particulate filter must 5 be regenerated at regular intervals. For this purpose, the engine can be activated so that the exhaust gas temperature is raised to such a high level that the soot particles trapped in the filter burn. Alternatively, unburned fuel may be injected into the exhaust gases to increase the exhaust gas temperature. The efficiency of the SCR catalyst 6 is reduced at very high temperatures. Its active layers can also be damaged by too hot exhaust gases, which consequently leads to a shortening of its life. The control unit 12 receives information indicating when the particulate filter should be regenerated. The control unit essentially receives information from the sensor without interruption 14 with respect to the temperature of the exhaust gases in the exhaust pipe near the catalyst. When the temperature of the exhaust gas rises above a certain threshold, the control unit brings the valve 11k in the third position, whereupon starting the pump 11m follows. Thus, cooled retarder oil from container 11b to the first heat exchanger 11f over the outlet pipe 11e promoted.

The control unit adjusts the position of the damper 3 such that the exhaust gases in the exhaust pipe through the second parallel pipe 2 B pass. The exhaust gases are absorbed by the oil in the first heat exchanger 11f cooled. The control unit essentially receives information from the sensor without interruption 14 in terms of the temperature of the exhaust gases near the catalyst. The control unit controls the valve 11i and thus the oil flow through the first heat exchanger such that the exhaust gases entering the catalyst are substantially never higher in temperature than the upper threshold. It is thus also possible for the catalyst to maintain optimal reduction of nitrogen oxides even in operating situations in which the particulate filter 5 is regenerated. Even in operating situations where the engine is under heavy load and the exhaust gases are at a higher temperature than the upper threshold, the control unit will be able to provide cooled retarder oil to the first heat exchanger 11f to direct and the valve 11i to control so that the temperature of the exhaust gases is reduced to a level below the threshold.

The invention is in no way limited to the embodiments to which the drawings refer, and may be freely varied within the scope of the claims. The exhaust treatment component need not be an SCR catalyst, but may be any type of exhaust treatment component that requires a relatively high temperature to achieve optimal treatment of exhaust gases.

Claims (12)

An arrangement for counteracting the cooling of an exhaust treatment component in a vehicle, the vehicle having an internal combustion engine ( 1 ), one with the engine ( 1 ) connected powertrain ( 9 . 10 ), an exhaust pipe ( 2 ), the exhaust gases from the engine ( 1 ), and at least one exhaust treatment component ( 6 ) located in an exhaust pipe ( 2 ), the arrangement being a braking system ( 11 ), which itself has a braking component in the form of a retarder ( 11a ) connected to the drive train ( 9 . 10 ) of the vehicle, and a first line ( 11c ), which is adapted to a liquid medium to the retarder ( 11a ) in operating situations in which the retarder ( 11a ) is activated, characterized in that the brake system ( 11 ) a first heat exchanger ( 11f ) for cooling the liquid medium contained in the exhaust pipe ( 2 ) at a point between the engine ( 1 ) and the exhaust treatment component ( 6 ), and a second line ( 11e ) for receiving warm liquid medium from the retarder ( 11a ) and for directing it to the first heat exchanger ( 11f ) is set up in operating situations in which the retarder ( 11a ) is activated. Arrangement according to claim 1, characterized in that the exhaust pipe ( 2 ) in two parallel lines ( 2a . 2 B ) is divided into a section which is between the engine ( 1 ) and the exhaust treatment component ( 6 ), and that the first heat exchanger ( 11f ) in one of said parallel lines ( 2 B ) is positioned. Arrangement according to claim 2, characterized in that it comprises a first flow element ( 3 ) for dividing the flow in the exhaust pipe between the two parallel lines ( 2a . 2 B ) is set up. Arrangement according to one of the preceding claims, characterized in that in the brake system it has a second flow element ( 11i ) for conducting a variable flow of the liquid medium to the first heat exchanger ( 11f ) is set up. Arrangement according to claims 3 and 4, characterized in that it comprises a control unit ( 12 ) which is used to control the first flow element ( 3 ) and / or the second flow element ( 11i ), and thus the heat transfer in the heat exchanger ( 11f ), when the retarder ( 11a ) is activated so that the gas in the exhaust pipe ( 2 ), which is the exhaust gas treatment component ( 6 ), has a temperature which is within a range in which the exhaust gas purification component ( 6 ) has an optimal exhaust gas treatment capability, and for controlling the heat transfer into the first heat exchanger ( 11f ) based on information from at least one sensor ( 14 ), the parameter related to the temperature of the exhaust gas treatment component ( 6 ) supervised. Arrangement according to claim 5, characterized in that the control unit ( 12 ) for receiving information from said sensor ( 14 ), the gas temperature within the exhaust pipe ( 2 ) at a point near the exhaust treatment components ( 6 ) supervised. Arrangement according to one of the preceding claims, characterized in that the brake system ( 11 ) a second heat exchanger ( 11g ), in which the liquid medium undergoes a second step of cooling. Arrangement according to one of the preceding claims, characterized in that it comprises a WHR system ( 8th ), which absorbs thermal energy from the gases in the exhaust pipe ( 2 ) at a point downstream of the exhaust treatment component ( 6 ) is set up. Arrangement according to one of the preceding claims, characterized in that the exhaust gas treatment component is an SCR catalyst ( 6 ). Arrangement according to claim 9, characterized in that the exhaust pipe ( 2 ) a particle filter ( 5 ) located upstream of the SCR catalyst, and in that said first heat exchanger ( 11f ) in the exhaust pipe ( 2 ) at a point between the particulate filter ( 5 ) and the SCR catalyst ( 6 ) is positioned. Arrangement according to one of the preceding claims, characterized in that the brake system ( 11 ) Flow components ( 11j . 11k . 11m ) for passing cooled liquid medium to the first Heat exchanger ( 11f ) are set up in operating situations when the retarder ( 11a ) is not activated. Arrangement according to claims 10 and 11, characterized in that said flow components ( 11j . 11k . 11m ) for conducting the liquid medium to the first heat exchanger ( 11f ) are set up in operating situations in which the particulate filter ( 5 ) is regenerated.

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