NL2029161B1 - An exhaust after treatment assembly. - Google Patents

An exhaust after treatment assembly. Download PDF

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Publication number
NL2029161B1
NL2029161B1 NL2029161A NL2029161A NL2029161B1 NL 2029161 B1 NL2029161 B1 NL 2029161B1 NL 2029161 A NL2029161 A NL 2029161A NL 2029161 A NL2029161 A NL 2029161A NL 2029161 B1 NL2029161 B1 NL 2029161B1
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NL
Netherlands
Prior art keywords
exhaust
heat exchanger
exhaust pipe
heat
exchanger
Prior art date
Application number
NL2029161A
Other languages
Dutch (nl)
Inventor
De Jong Dirk-Jan
Original Assignee
Daf Trucks Nv
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Application filed by Daf Trucks Nv filed Critical Daf Trucks Nv
Priority to NL2029161A priority Critical patent/NL2029161B1/en
Application granted granted Critical
Publication of NL2029161B1 publication Critical patent/NL2029161B1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/0205—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust using heat exchangers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/02—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/14—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a fuel burner
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/16—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an electric heater, i.e. a resistance heater
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
    • F01N2410/03—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device in case of low temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
    • F01N2410/06—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device at cold starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/103—Oxidation catalysts for HC and CO only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
    • F01N3/2013—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means

Abstract

An exhaust after treatment assembly comprises an exhaust pipe having an exhaust pipe inlet connected to an engine exhaust and an exhaust pipe outlet. A heating system is connected in the exhaust pipe and a selective catalytic reduction system is connected in the exhaust pipe downstream of the heating system. A gas-gas heat-exchanger is provided comprising a housing and a first heat-exchanger passage fluidly connecting a first heat- exchanger inlet to a first heat-exchanger outlet and a second heat-exchanger passage fluidly connecting a second heat exchanger inlet to a second heat- exchanger outlet. The first heat-exchanger inlet is connected to the exhaust pipe downstream of the engine and the first heat-exchanger outlet is connected to the exhaust pipe upstream of the heating system. The second heat-exchanger inlet is connected to the exhaust pipe downstream of the SCR system and the second heat-exchanger outlet is connected to the exhaust pipe upstream of the exhaust pipe outlet. The heat-exchanger is configured to put the exhaust gasses flowing through the second passage in heat transfer contact with the exhaust gasses flowing through the first passage. The exhaust treatment assembly further comprises a bypass pipe connected with a first end in the exhaust pipe upstream of the second heat- exchanger inlet, and connected with a second end in the exhaust pipe downstream of the second heat-exchanger outlet, wherein the bypass pipe comprises a bypass valve configured to selectively open or close the bypass pipe.

Description

P130874NL00
Title: An exhaust after treatment assembly.
The invention relates to an exhaust after treatment assembly configured to cooperate with a diesel combustion engine, the assembly comprising: - an exhaust pipe having an exhaust pipe inlet connected to an engine exhaust of the engine and an exhaust pipe outlet, the exhaust pipe being configured for leading exhaust gasses from the engine to the exhaust pipe outlet; - a heating system connected in the exhaust pipe; - a selective catalytic reduction (SCR) system connected in the exhaust pipe downstream of the heating system; and - a gas-gas heat-exchanger, the gas-gas heat-exchanger comprising: - a heat-exchanger housing comprising a first heat- exchanger inlet, a first heat-exchanger outlet, a second heat- exchanger inlet and a second heat-exchanger outlet; - a first heat-exchanger passage fluidly connecting the first heat-exchanger inlet to the first heat-exchanger outlet; and - a second heat-exchanger passage fluidly connecting the second heat exchanger inlet to the second heat-exchanger outlet; wherein the first heat-exchanger inlet is connected to the exhaust pipe downstream of the engine to receive exhaust gasses from the engine exhaust, wherein the first heat-exchanger outlet is connected to the exhaust pipe upstream of the heating system, wherein the second heat-exchanger inlet is connected to the exhaust pipe downstream of the SCR system to receive exhaust gasses from the SCR system, and wherein the second heat- exchanger outlet is connected to the exhaust pipe upstream of the exhaust pipe outlet, and wherein the heat-exchanger is configured to put the exhaust gasses flowing through the second passage in heat transfer contact with the exhaust gasses flowing through the first passage.
Such an exhaust after treatment assembly for an internal diesel combustion engine is for example known from DE102014005418A1. This known exhaust after treatment assembly comprises a separator (also called a Diesel Oxidation Catalyst (DOC)), arranged downstream of an internal combustion engine for the chemisorption of sulfur oxides and a gas-gas heat exchanger. The gas-gas heat exchanger is arranged such that on the one hand exhaust gas guided via the separator and, on the other hand, exhaust gas leaving the internal diesel combustion engine 1s passed through the gas- gas heat exchanger to raise the temperature of the exhaust gas leaving the internal diesel combustion engine. The known exhaust after treatment assembly is further provided with a heating device arranged downstream of the gas-gas heat exchanger and upstream of the separator to further increase the temperature of the exhaust gas routed via the gas-gas heat exchanger. The gas-gas heat exchanger and the heating device arranged downstream of the gas-gas heat exchanger allow the temperature of the exhaust gas to be routed through the separator to be controlled to an optimum temperature for desulfurization of the exhaust gas in the separator. The known exhaust after treatment assembly further comprises an SCR catalytic converter which can be positioned either downstream of the separator and upstream of the gas-gas heat exchanger, or which can alternatively be positioned downstream of the gas-gas heat exchanger. In the SCR catalytic converter, the exhaust gas is denitrified and thus a further reduction in exhaust gas emissions can be obtained. During a cold engine start, however, the engine exhaust will be heating the heat exchanger thereby delaying the separator and the SCR from reaching normal operating temperatures thereby negatively influencing the reduction in exhaust gas emissions.
It is thus an object of the invention to provide an exhaust after treatment assembly for an internal diesel combustion engine in which during a cold start the SCR can reach normal operating temperatures relatively quick. It is a further object of the invention to provide an exhaust after treatment assembly for an internal diesel combustion engine in which in case of leakages in the exhaust after treatment assembly undesired exhaust gas emissions are reduced.
According to the invention at least one of these objects is obtained by providing an exhaust after treatment assembly configured to cooperate with a diesel combustion engine, the assembly comprising: - an exhaust pipe having an exhaust pipe inlet connected to an engine exhaust of the engine and an exhaust pipe outlet, the exhaust pipe being configured for leading exhaust gasses from the engine to the exhaust pipe outlet; - a heating system connected in the exhaust pipe; - a selective catalytic reduction (SCR) system connected in the exhaust pipe downstream of the heating system; and - a gas-gas heat-exchanger, the gas-gas heat-exchanger comprising: - a heat-exchanger housing comprising a first heat-exchanger inlet, a first heat-exchanger outlet, a second heat-exchanger inlet and a second heat-exchanger outlet; - a first heat-exchanger passage fluidly connecting the first heat- exchanger inlet to the first heat-exchanger outlet; and - a second heat-exchanger passage fluidly connecting the second heat exchanger inlet to the second heat-exchanger outlet; wherein the first heat-exchanger inlet is connected to the exhaust pipe downstream of the engine to receive exhaust gasses from the engine exhaust, wherein the first heat-exchanger outlet is connected to the exhaust pipe upstream of the heating system, wherein the second heat-exchanger inlet is connected to the exhaust pipe downstream of the SCR system to receive exhaust gasses from the SCR system, and wherein the second heat- exchanger outlet is connected to the exhaust pipe upstream of the exhaust pipe outlet, and wherein the heat-exchanger is configured to put the exhaust gasses flowing through the second passage in heat transfer contact with the exhaust gasses flowing through the first passage; characterized in that the exhaust treatment assembly further comprises a bypass pipe connected with a first end in the exhaust pipe upstream of the second heat-exchanger inlet, and connected with a second end in the exhaust pipe downstream of the second heat-exchanger outlet, wherein the bypass pipe comprises a bypass valve configured to selectively open or close the bypass pipe. In this manner, by providing said bypass pipe, the bypass valve can be opened after a cold start such that exhaust gasses can be diverted around the heat exchanger such that the exhaust gasses do no heat up the heat exchanger whereby start the SCR can reach normal operating temperatures relatively quick.
Once the diesel engine reaches normal operating temperatures the bypass valve can be closed to direct exhaust gas through the heat exchanger such that the heating system needs less energy to heat the exhaust gasses to the optimal operating temperature for the SCR. It is observed that according to the invention the bypass pipe is connected with a first end in the exhaust pipe upstream of the second heat-exchanger inlet, and connected with a second end in the exhaust pipe downstream of the second heat-exchanger outlet to eliminate undesired exhaust gas emissions in case of leakages in the assembly and to reduce temperature gradients on the exhaust after treatment assembly when opening or closing the bypass valve. In case the bypass pipe would be connected with a first end in the exhaust pipe upstream of the first heat-exchanger inlet, and connected with a second end in the exhaust pipe downstream of the first heat-exchanger outlet then undesired exhaust gas emissions in case of leakages in the assembly could occur and temperature gradients on the exhaust after treatment assembly when opening or closing the bypass valve could be present.
In an embodiment of an exhaust after treatment assembly according to the invention walls of the first passage and/or second passage of 5 the heat-exchanger are provided with a catalytic coating. In this manner conversion of either NO, and/or hydrocarbons is promoted.
In another embodiment of an exhaust after treatment assembly according to the invention, the exhaust after treatment assembly further comprises: - a heating system temperature sensor located in the exhaust pipe directly downstream of the heating system configured to determine a temperature of the exhaust gasses in the exhaust pipe; and - a heating system controller configured to turn the heating system on when the temperature determined by the heating system temperature sensor is below a predetermined reference temperature, and to turn the heating system off when the temperature determined by the heating system temperature sensor is above the predetermined reference temperature. In this manner a control strategy for efficiently operating the heating system can be provided in order to reduce the energy needed to operate the heating system. The predetermined reference temperature preferably is the optimal operating temperature of the SCR, for example 300°C. The heating system can be embodied as a burner heating device, an electrical heating device or fuel dosing over a diesel oxidation catalyst.
In a further embodiment of an exhaust after treatment assembly according to the invention, the exhaust after treatment assembly further comprises: - a first heat-exchanger temperature sensor located in the exhaust pipe directly upstream of the first passage of the heat-exchanger and configured to determine a temperature of the exhaust gasses in the exhaust pipe;
- a second heat-exchanger temperature sensor located in the exhaust pipe upstream of the second passage of the heat-exchanger and downstream of the selective catalytic reduction (SCR) system and configured to determine a temperature of the exhaust gasses in the exhaust pipe; and - a bypass controller configured to open the bypass valve when a temperature determined by the first heat-exchanger temperature sensor is higher that a temperature determined by the second heat-exchanger temperature sensor, and to close the bypass valve when the temperature determined by the first heat-exchanger temperature sensor is lower than the temperature determined by the second heat-exchanger temperature sensor. In this manner an effective control of the bypass valve can be obtained in which temperature gradients over the SCR system are reduced thereby increasing its lifespan.
The invention will be further explained with reference to the
Figure, in which a non-limiting exemplary embodiment of a vehicle according to the invention is shown:
Fig. 1 schematically shows an embodiment of an exhaust after treatment assembly according to the invention.
In Fig. 1 an example of an embodiment of an exhaust after treatment assembly 1 configured to cooperate with a diesel combustion engine 2 is schematically shown. The exhaust after treatment assembly 1 comprises an exhaust pipe 3 with an exhaust pipe inlet 4 connected to an engine exhaust 5 of the engine 2 and an exhaust pipe outlet 6. The exhaust pipe 3 is configured for leading exhaust gasses from the engine 2 to the exhaust pipe outlet 6 from which the exhaust gasses are discharged into the environment.
A selective catalytic reduction (SCR) system 7 is connected in the exhaust pipe 3 to reduce the amount of NO, in the exhaust gasses. As the selective catalytic reduction (SCR) system 7 operates by chemical reactions to reduce NO, it requires a certain minimum temperature to achieve its optimal efficiency. According to the invention a temperature of 200°C, at which temperature typically the chemical reactions start, can be reached relatively quick such that injection of e.g. urea can be started relatively quick, and also a temperature of about 300°C, at which the chemical reactions reach optimum efficiency, can be reached relatively quick. In order to obtain such temperatures a heating system 8 is connected in the exhaust pipe 3, such that the selective catalytic reduction (SCR) system 7 is arranged downstream of the heating system 8. The heating system 8 can be formed by an electric heater, a fuel burner and/or fuel dosing over a Diesel
Oxidation Catalyst (DOC).
The exhaust after treatment assembly 1 further comprises a gas- gas heat-exchanger 9 which has a heat-exchanger housing 10 comprising a first heat-exchanger inlet 111 a first heat-exchanger outlet 110, a second heat-exchanger inlet 121 and a second heat-exchanger outlet 120. A first heat-exchanger passage 13 fluidly connects the first heat-exchanger inlet 111 to the first heat-exchanger outlet 110 and a second heat-exchanger passage 14 fluidly connects the second heat exchanger inlet 121 to the second heat-exchanger outlet 120.
As shown in Figure 1 the first heat-exchanger inlet 111i is connected to the exhaust pipe 3 downstream of the engine 2 to receive exhaust gasses from the engine exhaust 5. The first heat-exchanger outlet 110 is connected to the exhaust pipe 3 upstream of the heating system 8. The second heat- exchanger inlet 12i is connected to the exhaust pipe 3 downstream of the selective catalytic reduction (SCR) system 7 to receive exhaust gasses from the selective catalytic reduction (SCR) system 7. The second heat-exchanger outlet 120 is connected to the exhaust pipe 3 upstream of the exhaust pipe outlet 6. The heat-exchanger 9 is configured to put the exhaust gasses flowing through the second passage 14 in heat transfer contact with the exhaust gasses flowing through the first passage 13 such that heat from the chemical reactions reducing NO, can be used to heat the exhaust gasses entering the heating system 8, as a result of which the heating system 8 requires less energy for heating the exhaust gasses to the optimal temperature for NO, conversion. Preferably the walls of the first passage 13 and/or second passage 14 of the heat-exchanger 9 are provided with a catalytic coating in order to promote conversion of either NO, and/or hydrocarbons.
A heating system temperature sensor 15 is located in the exhaust pipe 3 directly downstream of the heating system 8 and the heating system temperature sensor 15 is configured to determine a temperature of the exhaust gasses in the exhaust pipe 3 directly downstream of the heating system 8. The heating system temperature sensor 15 provides a signal indicative for the measured temperature to a heating system controller 16 which is configured to turn the heating system 8 on when the temperature determined by the heating system temperature sensorl5 is below a predetermined reference temperature, preferably about 300°C, and to turn the heating system 8 off when the temperature determined by the heating system temperature sensor 15 is above the predetermined reference temperature. In this manner the amount of fuel needed for operating the heating system 8 is reduced since the heating system 8 is only operated when necessary, e.g. after a cold engine start or during low engine load conditions.
The embodiment of the exhaust after treatment assembly 1 as shown in Figure 1 is further provided with a first heat-exchanger temperature sensor 17 located in the exhaust pipe 3 directly upstream of the first passage 13 of the heat-exchanger 9 for determining a temperature of the exhaust gasses in the exhaust pipe 3. A second heat-exchanger temperature sensor 18 is located in the exhaust pipe 3 upstream of the second passage 14 of the heat-exchanger 9 and downstream of the selective catalytic reduction (SCR) system 7 and is configured to determine a temperature of the exhaust gasses in the exhaust pipe 3.
According to the invention the exhaust treatment assembly 1 further comprises a bypass pipe 19 connected with a first end 20 in the exhaust pipe 3 upstream of the second heat-exchanger inlet 121, and connected with a second end 21 in the exhaust pipe 3 downstream of the second heat-exchanger outlet 120. The second heat-exchanger temperature sensor 18 is preferably located in the exhaust pipe 3 upstream of the first end 20 of the bypass pipe 19.
In the bypass pipe 19 a bypass valve 22 is positioned which is controlled by a bypass controller 23 to selectively open or close the bypass pipe 19. The bypass controller 23 is configured to receive signals from the first and second heat-exchanger temperature sensors 17, 18 in order to open the bypass valve 22 when a temperature determined by the first heat- exchanger temperature sensor 17 is higher that a temperature determined by the second heat-exchanger temperature sensor 18, i.e. after a cold start or during low engine load conditions, and to close the bypass valve 22 when the temperature determined by the first heat-exchanger temperature sensor 17 is lower than the temperature determined by the second heat-exchanger temperature sensor 18. In this manner e.g. during a cold start the bypass valve 22 is closed so that a substantial amount of heat in the exhaust gasses coming from the engine is used the heat up the selective catalytic reduction (SCR) system 7 instead of the heat exchanger 9. As a result thereof the SCR system 7 is heated up more quickly to its optimal operating temperature with the same power usage of the heating system 8, thereby reducing exhaust gas emissions. Since the bypass pipe is connected with its first end 20 in the exhaust pipe 3 upstream of the second heat-exchanger inlet 121 and with its second end 21 in the exhaust pipe 3 downstream of the second heat-exchanger outlet 120, i.e. is placed on the outlet side of the heat exchanger 9, additional emissions in case of leakages are eliminated and temperature gradients on the SCR system 7 when opening or closing the bypass pipe 19 are reduced thereby increasing its lifespan.

Claims (4)

ConclusiesConclusions 1. Een uitlaatnabehandelingssamenstel geconfigureerd om samen te werken met een dieselverbrandingsmotor, waarbij het samenstel omvat: - een uitlaatpijp met een uitlaatpijpinlaat verbonden met een motoruitlaat van de motor en een uitlaatpijpuitlaat, waarbij de witlaatpijp geconfigureerd is om uitlaatgassen van de motor naar de uitlaatpijpuitlaat te leiden; - een verwarmingssysteem verbonden in de uitlaatpijp; - een systeem voor selectieve katalytische reductie (SCR) dat is verbonden in de uitlaatpijp stroomafwaarts van het verwarmingssysteem; en - een gas-gas warmtewisselaar, waarbij de gas-gas warmtewisselaar omvat: - een warmtewisselaarbehuizing omvattende een eerste warmtewisselaarinlaat, een eerste warmtewisselaaruitlaat, een tweede warmtewisselaarinlaat en een tweede warmtewisselaaruitlaat; - een eerste warmtewisselaardoorgang die de eerste warmtewisselaarinlaat fluidaal verbindt met de eerste warmtewisselaaruitlaat; en - een tweede warmtewisselaardoorgang die de tweede warmtewisselaarinlaat fluidaal verbindt met de tweede warmtewisselaaruitlaat; waarbij de eerste warmtewisselaarinlaat 1s verbonden op de uitlaatpijp stroomafwaarts van de motor om uitlaatgassen van de motorwtlaat te ontvangen, waarbij de eerste warmtewisselaaruitlaat is verbonden op de uitlaatpijp stroomopwaarts van het verwarmingssysteem,1. An exhaust aftertreatment assembly configured to cooperate with a diesel internal combustion engine, the assembly comprising: - an exhaust pipe having an exhaust pipe inlet connected to an engine engine exhaust and an exhaust pipe outlet, the white tail pipe being configured to direct exhaust gases from the engine to the exhaust pipe outlet ; - a heating system connected in the exhaust pipe; - a Selective Catalytic Reduction (SCR) system connected in the exhaust pipe downstream of the heating system; and - a gas-gas heat exchanger, wherein the gas-gas heat exchanger comprises: - a heat exchanger housing comprising a first heat exchanger inlet, a first heat exchanger outlet, a second heat exchanger inlet and a second heat exchanger outlet; - a first heat exchanger passageway fluidly connecting the first heat exchanger inlet to the first heat exchanger outlet; and - a second heat exchanger passageway fluidly connecting the second heat exchanger inlet to the second heat exchanger outlet; wherein the first heat exchanger inlet is connected to the exhaust pipe downstream of the engine to receive exhaust gases from the engine outlet, the first heat exchanger outlet is connected to the exhaust pipe upstream of the heating system, waarbij de tweede warmtewisselaarinlaat is verbonden op de uitlaatpijp stroomafwaarts van het SCR-systeem om uitlaatgassen van het SCR- systeem te ontvangen, en waarbij de tweede warmtewisselaaruitlaat is verbonden op de uitlaatpijp stroomopwaarts van de witlaatpijpuitlaat, en waarbij de warmtewisselaar is geconfigureerd om de uitlaatgassen die door de tweede doorgang stromen in warmteoverdrachtscontact te brengen met de uitlaatgassen die door de eerste doorgang stromen; met het kenmerk dat het uitlaatgasbehandelingssamenstel verder een bypass-leiding omvat die met een eerste uiteinde is verbonden in de uitlaatpijp stroomopwaarts van de tweede warmtewisselaarinlaat, en met een tweede uiteinde verbonden in de uitlaatpijp stroomafwaarts van de tweede warmtewisselaaruitlaat, waarbij de bypass-leiding een bypass-klep omvat die is geconfigureerd om de bypass-leiding selectief te openen of te sluiten.wherein the second heat exchanger inlet is connected to the exhaust pipe downstream of the SCR system to receive exhaust gases from the SCR system, and the second heat exchanger outlet is connected to the exhaust pipe upstream of the white exhaust pipe outlet, and the heat exchanger is configured to receive the exhaust gases bringing streams through the second passage into heat transfer contact with the exhaust gases flowing through the first passage; characterized in that the exhaust gas treatment assembly further comprises a bypass conduit connected at a first end in the exhaust pipe upstream of the second heat exchanger inlet and connected at a second end in the exhaust pipe downstream of the second heat exchanger outlet, the bypass conduit comprising a bypass valve configured to selectively open or close the bypass line. 2. Het uitlaatgasnabehandelingssamenstel volgens conclusie 1, waarbij de wanden van de eerste doorgang en/of tweede doorgang van de warmtewisselaar zijn voorzien van een katalytische coating.The exhaust gas after-treatment assembly according to claim 1, wherein the walls of the first passage and/or second passage of the heat exchanger are provided with a catalytic coating. 3. Het uitlaatgasnabehandelingssamenstel volgens conclusie 1 of 2, verder omvattende: - een temperatuursensor van het verwarmingssysteem die zich m de uitlaatpijp direct stroomafwaarts van het verwarmingssysteem bevindt, geconfigureerd om de temperatuur van de uitlaatgassen in de uitlaatpijp te bepalen; en - een verwarmingssysteemcontroller die is geconfigureerd om het verwarmingssysteem in te schakelen wanneer de temperatuur bepaald door de temperatuursensor van het verwarmingssysteem lager is dan een vooraf bepaalde referentietemperatuur, en om het verwarmingssysteem uit te schakelen wanneer de temperatuur bepaald door de temperatuursensor van het verwarmingssysteem hoger is dan de vooraf bepaalde referentietemperatuur.The exhaust gas after-treatment assembly according to claim 1 or 2, further comprising: - a temperature sensor of the heating system located in the exhaust pipe immediately downstream of the heating system, configured to determine the temperature of the exhaust gases in the exhaust pipe; and - a heating system controller configured to turn on the heating system when the temperature determined by the temperature sensor of the heating system is lower than a predetermined reference temperature, and to turn off the heating system when the temperature determined by the temperature sensor of the heating system is higher than the predetermined reference temperature. 4. Het utlaatgasnabehandelingssamenstel volgens een van de voorgaande conclusies, verder omvattende: - een eerste warmtewisselaartemperatuursensor die zich in de uitlaatpijp direct stroomopwaarts van de eerste doorgang van de warmtewisselaar bevindt en is geconfigureerd om een temperatuur van de uitlaatgassen in de wtlaatpijp te bepalen; - een tweede temperatuursensor van de warmtewisselaar die zich in de witlaatpijp bevindt, stroomopwaarts van de tweede doorgang van de warmtewisselaar en stroomafwaarts van het systeem voor selectieve katalytische reductie (SCR) en geconfigureerd om een temperatuur van de uitlaatgassen in de wtlaatpijp te bepalen; en - een bypass-controller die is geconfigureerd om de bypass-klep te openen wanneer een temperatuur bepaald door de eerste temperatuursensor van de warmtewisselaar hoger is dan een temperatuur bepaald door de tweede temperatuursensor van de warmtewisselaar, en om de bypass-klep te sluiten wanneer de temperatuur bepaald door de eerste temperatuursensor van de warmtewisselaar lager is dan de temperatuur bepaald door de tweede temperatuursensor van de warmtewisselaar.The exhaust gas after-treatment assembly according to any of the preceding claims, further comprising: - a first heat exchanger temperature sensor located in the exhaust pipe immediately upstream of the first heat exchanger passage and configured to determine a temperature of the exhaust gases in the exhaust pipe; - a second heat exchanger temperature sensor located in the white exhaust pipe, upstream of the second heat exchanger passage and downstream of the Selective Catalytic Reduction (SCR) system and configured to determine a temperature of the exhaust gases in the exhaust pipe; and - a bypass controller configured to open the bypass valve when a temperature determined by the first heat exchanger temperature sensor exceeds a temperature determined by the second heat exchanger temperature sensor, and to close the bypass valve when the temperature determined by the first temperature sensor of the heat exchanger is lower than the temperature determined by the second temperature sensor of the heat exchanger.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2078834A1 (en) * 2008-01-10 2009-07-15 Haldor Topsoe A/S Method and system for purification of exhaust gas from diesel engines
EP2153036A1 (en) * 2007-05-03 2010-02-17 Mack Trucks, Inc. Exhaust aftertreatment system
DE102014005418A1 (en) 2014-04-14 2015-10-15 Man Diesel & Turbo Se Exhaust after-treatment system and exhaust aftertreatment process

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2153036A1 (en) * 2007-05-03 2010-02-17 Mack Trucks, Inc. Exhaust aftertreatment system
EP2078834A1 (en) * 2008-01-10 2009-07-15 Haldor Topsoe A/S Method and system for purification of exhaust gas from diesel engines
DE102014005418A1 (en) 2014-04-14 2015-10-15 Man Diesel & Turbo Se Exhaust after-treatment system and exhaust aftertreatment process

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