DE102005025434B4 - Emission control device for a motor - Google Patents

Abstract

Emission control device for an internal combustion engine, which can be operated in a plurality of combustion modes, one of which is a lean combustion mode, wherein the emission control device comprises an exhaust gas turbocharger (20, 320, 420) with a compressor (350, 450) and a turbine (351, 451), at least an exhaust emission control device disposed downstream of the turbocharger (20, 320, 420) for receiving exhaust therefrom and including a valve controlled wastegate passage (316, 424) to connect the turbine (351, 451) of the turbocharger (20, 320, 420), wherein an exhaust gas cooler (13, 313, 413) is arranged such that it specifically cools at least part of the exhaust gases flowing from the turbocharger (20, 320, 420) to the at least one emission control device.

Description

This invention relates to internal combustion engines, and more particularly to an emissions control device for a lean-burn engine.

It is known to provide an internal combustion engine which can be operated in more than one combustion mode, for example in a lean combustion mode, a stoichiometric combustion mode and a rich combustion mode.

To reduce the pollutants of such an engine, a three-way catalyst is used for combustion that is stoichiometric or rich, but such a catalyst is not effective when the engine is operating in the lean combustion mode, and therefore lean NOx storage is also normally used.

A problem with lean NOx storage is that it must operate within a fairly limited temperature range if it is to operate efficiently and quickly degrade its performance if the temperature of the exhaust gases passing through it is excessive for too long a period of time.

The following developments are known from the prior art.

To DE 690 13 869 T2 is known a method and apparatus for heat energy recovery in a large diesel engine, which is also provided with a turbocharger. The heat energy of the engine exhaust gases is thereby recovered at least partially and independently of the mechanical power generation of the engine in two phases. First, before passing the exhaust gases through the turbocharger, to produce hot water and steam and, second, after passing through the turbocharger, to preheat feed water to produce hot water and steam. At utilization below the maximum load, at least part of the exhaust gases can be fed directly into the turbocharger.

The EP 1 286 026 A1 discloses an exhaust system of a motor vehicle having between a near-engine three-way catalytic converter and an upstream of the exhaust NOx adsorber a connecting tube having three concentric ducts.

The US Pat. No. 6,330,910 B1 describes a heat exchanger for a vehicle exhaust mounted in a tubular body. The body has an internal structure such that there are at least two passages at the height of the heat exchanger, so that flowing exhaust gases can also bypass the heat exchanger.

The US Pat. No. 6,675,579 B1 discloses a device for off and at least partial recirculation of gas from or into an internal combustion engine, wherein pressure and temperature of the gas mixture can be regulated.

The US Pat. No. 6,519,931 B2 discloses a spark-initiating direct injection fuel internal combustion engine wherein a turbocharger and a catalyst are integrated into the structure. There is also a bypass channel, past the turbocharger turbine and controlled by means of a control valve.

JP H05-321643 discloses an exhaust system with turbocharger, wherein a rapid response of the turbocharger is ensured by rapid increase in temperature of an auxiliary catalyst, if the engine is cooled. The turbocharger turbine, the auxiliary and the main catalytic converter are arranged in the exhaust.

An object of this invention is to provide a pollution control device and an internal combustion engine which enables positioning of a lean NOx trap near an exhaust outlet of an engine without suffering from rapid thermal aging.

According to a first embodiment of the invention, an emission control device for an internal combustion engine is provided, which can be operated in a plurality of combustion modes, one of which is a lean combustion mode, wherein the emission control device comprises an exhaust gas turbocharger with a compressor and a turbine, at least one downstream of the turbocharger Exhaust emission control device to receive from this exhaust gas, and includes a valve controlled wastegate channel to bypass the turbine of the turbocharger targeted, wherein an exhaust gas cooler is arranged so that it at least a portion of the exhaust gas flowing from the turbocharger to the at least one emission control device targeted cools.

The at least one emission control device may be a lean NOx storage.

The at least one emission control device may be a three-way catalyst and a lean NOx storage.

The lean NOx trap may be located downstream of the three way catalyst.

Preferably, the three-way catalyst and the lean NOx storage are housed in a common housing.

According to first and second embodiments of the invention, the exhaust gas cooler may be accommodated in the wastegate channel.

The wastegate passage may be formed by a separate pipe having an inlet end operatively connected upstream of the turbine and an outlet end connected downstream of the turbine.

Alternatively, the wastegate channel may be formed as part of a housing of the turbocharger.

A wastegate valve may be used to control the flow of exhaust gases through the wastegate duct.

The wastegate valve may be used to only allow exhaust gases to flow through the charge pressure control channel when predetermined engine operating conditions exist.

According to a third embodiment of the invention, the wastegate duct may have an inlet end upstream of the turbine and an outlet end downstream of the turbine, the exhaust gas cooler may be mounted downstream of the turbine of the turbocharger, and a bypass passage may be provided to selectively bypass the exhaust gas cooler.

In this case, a wastegate valve may be used to control the flow of exhaust gases through the wastegate duct, and a bypass valve may be used to control the flow of exhaust gases through the bypass duct.

When the engine is operating at high load, the bypass valve may be actuated to close the bypass passage so that substantially all exhaust gases flow through the exhaust cooler.

Advantageously, at least during operation of the engine in the lean combustion mode, the bypass valve may be controlled to control the temperature of the exhaust gases flowing to the at least one emission control device.

According to a second embodiment of the invention, an internal combustion engine is provided, which is operable in at least one lean combustion mode, wherein the engine has an emission control device according to the first aspect of the invention.

• 1 ein schematisches Diagramm eines Motors und einer Schadstoffbegrenzungseinrichtung nach einer ersten erfindungsgemäßen Ausführung;
• 2 ein schematisches Diagramm eines Motors und einer Schadstoffbegrenzungseinrichtung nach einer zweiten erfindungsgemäßen Ausführung; und
• 3 ein schematisches Diagramm eines Motors und einer Schadstoffbegrenzungseinrichtung nach einer dritten erfindungsgemäßen Ausführung.

The invention will now be described by way of example with reference to the accompanying drawings. Hereby show:

• 1 a schematic diagram of an engine and an emission control device according to a first embodiment of the invention;
• 2 a schematic diagram of an engine and an emission control device according to a second embodiment of the invention; and
• 3 a schematic diagram of an engine and an emission control device according to a third embodiment of the invention.

With reference to 1 becomes an engine operable in three separate combustion modes 10 shown in a lean combustion mode in which the air-fuel ratio is higher than a stoichiometric air-fuel ratio, a stoichiometric mode in which the air-fuel ratio is stoichiometric, and a rich combustion mode in which the air-fuel ratio is lower is a stoichiometric air-fuel ratio.

It becomes a pollution control device for the engine 10 provided to eliminate the exhaust emissions from this. The emission control device comprises a turbocharger connected in this way 20 that he has exhaust from the engine 10 absorbs, an exhaust gas cooler 13 , a first emission control device in the form of a three-way catalyst 14 and a second emission control device in the form of a lean NOx storage 15 which is downstream of the three-way catalyst 14 is arranged.

From the engine 10 to the three-way catalyst 14 and the lean NOx storage 15 are two exhaust gas flow passages 16 . 17 provided, a first passage 16 in which the exhaust gas cooler 13 attached, and a second passage 17 which is the exhaust gas cooler 13 bypasses and through which the exhaust gases by a (in 1 not shown) turbine, which is part of the turbocharger 20 forms. The second passage 17 is as an integral part of the turbocharger 20 educated.

After flowing through the lean NOx storage 15 the exhaust gases flow through a silencer system (not shown) to a tailpipe (not shown).

A valve 12 is operable to control the flow of exhaust gases through the first passage 16 to control, and in this case is the valve 12 a wastegate valve and the first passage is a separate wastegate passage in the form of a pipeline extending between upstream of a turbine of the turbocharger 20 extends to a position downstream of the turbine.

As known in the art, there is the function of the wastegate valve 12 in it, the turbine of the turbocharger 20 to get around when passing through the turbocharger 20 generated air pressure reaches a predetermined value to a occurring due to high intake air pressure damage to the engine 10 to prevent. The wastegate valve 12 therefore opens normally when the engine is running at high speed and load, as these are the conditions where the air pressure of the exhaust from the turbocharger 20 often exceeds the required value.

However, it can be seen that a significant percentage of the exhaust gases pass through the second passage 17 flows even if the inlet to the first passage 16 is open because the resistance to flow through the second passage 17 is much lower than the resistance to flow through the exhaust gas cooler 13 ,

The valve 12 can be actuated by any suitable means, but in this case is a vacuum actuated actuator (not shown) with the valve 12 connected. The vacuum actuated actuator is in this case controlled by an electronic control unit (not shown) programmed to operate the valve 12 so moved that the outlet pressure of the turbocharger 20 is limited. Temperature sensors (not shown) serve to provide the electronic control unit with the temperature of the exhaust gases at one or more positions.

The exhaust gas cooler 13 is with a (not shown) main cooling circuit of the engine 10 connected. Coolant from the main cooling circuit flows through the exhaust gas cooler 13 and then returned to the main cooling circuit. All through the first passage 16 flowing exhaust gases must pass through the exhaust gas cooler 13 flow and are through the exhaust gas cooler 13 cooled. This means that every time exhaust fumes pass through the first passage 16 causes the temperature in the three-way catalyst 14 penetrating exhaust gases is lowered. The reason for this is that the cooled exhaust gases from the first passage 16 mix with the hot exhaust gases passing through the second passage 17 at the turbine of the turbocharger 20 have passed, and the mixing of these two streams produces a temperature between the two temperatures. The actual temperature depends on the respective flow velocities and temperatures.

The operation of the emission control device is as follows. From a cold start, it is desirable to use the three way catalyst 14 warm up quickly, and therefore the valve will 12 ideally positioned to allow the flow of exhaust gases through the second passage. This will almost always be the case as the engine 10 immediately after starting usually does not work at such a high speed or load that the discharge of exhaust gases through the first passage 16 is required.

It is desirable to control the temperature of the lean NOx storage 15 flowing exhaust gases within fairly narrow limits, which in this case are 400 ° C to 450 ° C, but this could be dependent on the design of the lean NOx storage 15 other limits.

During normal engine operation, when the engine is operating under lean load or part load conditions in the lean combustion mode, the temperature of the exhaust gases is normally such that the temperature of the lean NOx storage tank is such 15 penetrating exhaust gases is within this range and there is no need to cool the exhaust gases.

But if the temperature of the exhaust gas exceeds this upper limit of 450 ° C, the valve is 12 arranged so that it is opened by the electronic control unit to a portion of the exhaust gases through the first passage 16 to increase the performance of the lean NOx storage 15 to maximize.

When the engine is operating under high load or full load conditions, the valve is 12 under the control of the electronic control unit so operable that it is the first passage 16 opens to drain excess exhaust and prevent the pressure of the engine 10 supplied air exceeds a safe limit.

But if the air pressure limit is not reached, the valve can 12 be opened by the electronic control unit, if it is determined that the temperature of the lean NOx storage 15 penetrating exhaust gas has reached a temperature at which rapid thermal aging of the lean NOx storage 15 entry. This has the effect of lowering the temperature of the exhaust gases, causing thermal aging of the lean NOx storage 15 is minimized. The control of the valve 12 depends in these circumstances on the actual control logic used, but in In all cases there is a balance between ensuring that the engine 10 maximum power can be generated, and the need for premature aging of the lean-NOx storage 15 to prevent. Normally, premature aging occurs when the exhaust gas temperature exceeds 600 ° C.

It will be appreciated that under all high load conditions, the temperature of the exhaust gases is likely to be the preferred upper temperature limit of 450 ° C of lean NOx storage 15 exceeds. However, the emission performance of the emission control device is not seriously affected by these high temperatures because the engine operates at those high loads outside of the lean operating mode and in most cases in the rich operating mode where the lean NOx storage 15 is ineffective and the three-way catalyst 14 is used for eliminating unwanted pollutants from the exhaust gases. As the three-way catalyst 14 Therefore, the efficiency of the emission control device is not greatly affected in a wide temperature range, and especially at high temperatures.

Therefore, by positioning the exhaust gas cooler 13 in the wastegate channel 16 a warm up of the three-way catalyst 14 does not adversely affect the lean NOx storage 15 but can be minimized when the engine is operating at high load.

It will be understood that the valve described above is controlled not only by the need to control the pressure of the air supplied to the engine, but also by the temperature of the exhaust gases, which need not be the case, and that according to the invention, in a boost pressure control Channel of a conventional turbocharger arranged exhaust gas cooler, which has only a pressure control is also envisaged. Such an arrangement is also advantageous because under conditions of high engine load, when high exhaust gas temperatures are generated, the wastegate valve is likely to be open, and therefore exhaust fumes will occur, decreasing the likelihood of premature thermal aging of the lean NOx trap.

With reference to 2 A second embodiment of an emission control system is shown, which in many respects is the same as that described above and differs from the one described in 1 differs in that the three-way catalyst 14 and the lean NOx storage 15 in a common housing 22 are accommodated, which leads to a (not shown) exhaust system leading outlet 18 and that the first and second passages 316 . 317 as an integral part of a housing 323 for the turbocharger 320 are formed.

As before, the three-way catalyst is located 14 upstream of the lean NOx storage 15 so that the exhaust gases through the three-way catalyst 14 flow before entering the lean NOx storage 15. The housing 22 is at an inlet end to the exhaust gas turbocharger 320 operatively connected. The engine (not shown) to which the turbocharger 320 is operable as before in at least one lean combustion mode and in this case is operable in lean, stoichiometric and rich combustion modes.

The housing 323 of the turbocharger 320 forms an exhaust gas inlet channel 332 for supplying exhaust gases from the engine to a turbine 351 , one with the housing 22 operatively connected exhaust outlet 333 , an air intake 330 for supplying air to a compressor 350 and an air outlet for supplying compressed air to the engine via a charge air cooler (not shown) and the first and second fluid passages 316 . 317 out. The first passage 316 is in the form of a wastegate channel and has an exhaust gas cooler mounted therein 313 on. The second passage 317 bypasses the exhaust gas cooler 313 and provides a channel through which the exhaust gases flow to the turbine 351 drive.

In practice, the exhaust gas inlet duct is 332 directly connected to an exhaust manifold (not shown) of the engine.

The compressor 350 and the turbine 351 are attached to a common shaft, allowing the rotation of the turbine 351 by the flow of exhaust gases thereby rotation of the compressor 350 caused.

The exhaust gas cooler 313 is in the wastegate channel 316 arranged, which is from a position upstream of the turbine 351 to a position downstream of the turbine 351 extends. The exhaust gas cooler 313 is connected to a main cooling circuit (not shown) of the engine, from which refrigerant is extracted, through the exhaust gas cooler 313 and then led back to the main cooling circuit.

A wastegate valve 312 is operable to control the flow of exhaust gases through the first and second passages 316 and 317 to control, and in this case is the wastegate valve 312 a throttle valve operable to access the first passage 316 to close at an end position and access to the first passage 316 to open at an opposite end position. It is understood, however, that other valve arrangements can be used.

The wastegate valve 312 can be actuated by any suitable means, but in this case is an air-operated actuator (not shown) with the wastegate valve 312 connected. The air operated actuator is with the air outlet 331 connected to the turbocharger, so when the pressure in the air outlet 331 exceeds a predetermined pressure, the valve 312 is opened to the flow of through the turbine 351 to reduce flowing exhaust gases. It is understood, however, that other means for controlling the movement of the wastegate valve may be employed and that the valve could be controlled by an electronic control unit (not shown) programmed to operate the valve 312 to open and close when certain engine operating conditions are present.

The exhaust gas cooler 313 is provided to the temperature of the lean NOx storage 15 flowing exhaust gases when the engine is operating at high load.

By using the wastegate valve 312 For controlling the flow of exhaust gases through the first passage, a very simple device is provided in which at low engine load conditions all the exhaust gases flow through the turbine and thereby the exhaust gas cooler 313 but when the engine is under high load, the wastegate opens 312 , whereby the exhaust gases or at least a part thereof through the exhaust gas cooler 313 can flow. In practice, for example 35 up to 40% of the total exhaust gas flow through the exhaust gas cooler 313 when the wastegate valve is fully open and the engine is operating at high load. This is a significant advantage because when the engine is operating at high load, the exhaust gas temperature is high and it is desirable to have the maximum exhaust gas temperature, which is the lean NOx storage 15 is exposed to limit the thermal aging of the lean NOx storage 15 to minimize.

In an alternative to this arrangement, the wastegate valve 312 not just by the pressure in the air outlet 331 but also based on a need for lean NOx storage 15 To cool flowing exhaust gases or to support the warm-up of the engine from cold state. Temperature sensors (not shown) are used to provide the electronic control unit with the temperature of the exhaust gases at one or more positions.

In such an arrangement, the electronic control is programmed, the position of the wastegate valve 312 to control, with the need to prevent over-pressure in the air outlet 331 but also the need, if possible, the temperature of the lean NOx storage 15 within a predetermined temperature range is taken into account. Ie the boost pressure valve 312 is controlled by the electronic control unit to open and close when predetermined engine operating conditions exist.

When programming, a ranking system can be used to ensure that in all cases, as the wastegate valve to limit the pressure in the air outlet 331 must be opened, this is opened.

An advantage of such independent control is that after a cold start at low ambient temperature exhaust gases to the exhaust gas cooler 313 can be derived in order to accelerate the warm-up of the engine and also to improve the performance of the passenger compartment heating during engine warm-up.

Another advantage of such an arrangement is that the wastegate valve 312 can be opened and closed during lean engine operation to lower the lean NOx storage temperature 15 within or near the temperature at which its maximum operating performance is achieved, regardless of whether the pressure in the air outlet 331 high enough to the valve 312 to open. As is known in the art, it is desirable to control the temperature of the lean NOx storage 15 flowing exhaust gases to keep within a limited temperature range, which in this case is 400 ° C to 450 ° C, but could be different depending on the type of lean NOx storage used. When the lean NOx trap 15 is operated within this temperature range, it operates at peak conversion efficiency.

When the engine is operating at high load, the valve can 312 be operated so that the lean NOx storage 15 experienced maximum temperature by diverting a portion of the exhaust gases through the exhaust gas cooler 313 is lowered. This helps to prevent premature aging of the lean NOx storage 15 to prevent.

This temperature control of the valve 312 improves emission performance of the emission control device during lean combustion mode combustion and reduces the likelihood of premature thermal aging of the lean NOx storage device 15 ,

In both cases, it is advantageous that only one control valve is required to allow overpressure relief and control of exhaust gas cooling.

It will be understood that if desired, the three-way catalyst and the lean NOx storage could be accommodated in separate housings.

With reference to 3 a third embodiment of an emission control device according to the invention is shown.

As before with reference to 2 described are a three-way catalyst 14 and a lean NOx storage 15 in a common housing 22 housed, which leads to an exhaust system (not shown) outlet 18 having. The three-way catalyst 14 is upstream of the lean NOx storage 15 , so that exhaust gases through the three-way catalyst 14 flow before entering the lean NOx storage 15 penetration. The housing 22 is at an inlet end with an exhaust gas turbocharger 420 operatively connected.

As before, the engine is operable in at least one lean combustion mode and, in this case, is operable in the lean, stoichiometric, and rich combustion modes.

The turbocharger 420 has a housing 423 , which is an exhaust gas inlet duct 432 for supplying exhaust gases from the engine to a turbine 451 , one with the housing 22 operatively connected exhaust outlet 433 , an air intake 430 for supplying air to a compressor 450 as well as an air outlet 431 for supplying compressed air to the engine via a charge air cooler (not shown).

In practice, the exhaust gas inlet duct is 432 directly connected to an exhaust manifold (not shown) of the engine.

The compressor 450 and the turbine 451 are attached to a common shaft, allowing the rotation of the turbine 451 by the flow of exhaust gases thereby rotation of the compressor 450 caused.

A wastegate channel 424 is by itself from a position upstream of the turbine 451 to a position downstream of the turbine 451 extending extending separate pipe where it passes through a channel 460 with an exhaust duct from the turbine 451 connected is. A wastegate valve 402 is used to control the flow of exhaust gases, which in the wastegate channel 424 reach.

An exhaust gas cooler 413 is downstream of the turbine 451 in a first with the exhaust duct of the turbine 451 connected passage, and a bypass valve 412 serves to control the flow of exhaust gases through a second separate bypass passage 417 , which is arranged so that it exhaust gases from the turbine 351 to the outlet 18 can flow without them through the exhaust gas cooler 413 stream.

The exhaust gas cooler 413 is connected to a (not shown) main cooling circuit of the engine, of which coolant after flowing through the exhaust gas cooler 413 extracted and returned.

In this example, the wastegate valve 402 and the bypass valve 412 both bypass valves, but it will be understood that other valve arrangements could be used.

The wastegate and the bypass valve 402 . 412 may be actuated by any suitable means, but in this case a vacuum actuator (not shown) controlled by an electronic control unit (not shown) is associated with each valve 402 . 412 connected, and the valves 402 . 412 are controlled by the electronic control unit to open and close when predetermined engine operating conditions prevail. Temperature sensors (not shown) are used to provide the electronic control unit with the temperature of the exhaust gases at one or more positions.

The exhaust gas cooler 413 is provided to the temperature of the lean NOx storage 15 to lower flowing exhaust gases when the engine is operating at high load, and the temperature in the lean NOx storage 15 between predetermined limits when the engine is operating in the lean combustion mode.

The operation is as follows: after starting from cold state are the wastegate valve 402 and the bypass valve 412 both open, allowing them to unhindered hot exhaust gases to the three-way catalyst 14 and the lean NOx storage 15 let it flow. This speeds up the warm-up of the components and ensures that the onset of the three-way catalyst 14 as soon as possible after starting the engine to minimize engine emissions. After a short initial period, there is enough heat to the three-way catalyst 14 to ensure that popping has occurred, and at this point will be the bypass valve 412 closed to exhaust gases through the channel 460 to the exhaust gas cooler 413 redirect. The through the exhaust gas cooler 413 Heat recovered from the exhaust gases can then be used to lower the warm-up time of the engine and improve the performance of the passenger compartment heater. It will be understood by those skilled in the art that both emissions and fuel economy are adversely affected when an engine is not operating at or near its normal operating temperature.

The control of the two valves 402 . 412 by the electronic control unit is such that when the engine has reached or approaches its normal operating temperature, a third control mode is used, in which the wastegate valve 402 is controlled to the air pressure in the air outlet 431 limit, and the bypass valve 412 is used to control the temperature of the lean NOx storage 15 flowing exhaust gases when the engine is operating in lean combustion mode at light load or part load. This serves to maintain the temperature of the lean NOx storage 15 in a predetermined temperature range in which it operates at maximum power.

But if it is determined that the engine is operating at high load, then the bypass valve 412 closed and the wastegate valve 402 is controlled so that there is sufficient air pressure in the air outlet 431 provides the desired performance. In this arrangement, all the exhaust gases flow through the exhaust gas cooler 413 and so it comes to maximum cooling of the exhaust gases.

This arrangement is advantageous because when the engine is operating at high load, the exhaust gas temperature is very high and this is a rapid thermal aging of the lean NOx storage 15 can cause. Therefore, by maximizing the cooling of the exhaust gases, deterioration of the lean NOx storage becomes 15 minimized.

By using two valves for the separate and independent control of the wastegate passage and the bypass passage, better control can be realized than in the 2 As shown, but the cost of such an arrangement and the system complexity are higher. Although the wastegate channel and the bypass channel in 3 As shown as separate piping, it is understood that they could be formed as part of the turbocharger housing.

Thus, in summary, the invention provides an arrangement for selectively cooling exhaust gases from an engine to the hand, such that a temperature-sensitive emission control device, such as, for example, is provided. a lean NOx storage can be located near the outlet from the engine. In preferred embodiments of the present invention, a three-way catalyst and a lean NOx trap are housed in a single housing that can be connected close to the exhaust outlet of an engine using an upstream exhaust cooler. This is advantageous in terms of vehicle compactness and cost.

Claims (14)

Emission control device for an internal combustion engine, which can be operated in a plurality of combustion modes, one of which is a lean combustion mode, wherein the emission control device comprises an exhaust gas turbocharger (20, 320, 420) with a compressor (350, 450) and a turbine (351, 451), at least an exhaust emission control device disposed downstream of the turbocharger (20, 320, 420) for receiving exhaust therefrom and including a valve controlled wastegate passage (316, 424) to connect the turbine (351, 451) of the turbocharger (20, 320, 420), wherein an exhaust gas cooler (13, 313, 413) is arranged such that it specifically cools at least part of the exhaust gases flowing from the turbocharger (20, 320, 420) to the at least one emission control device. Setup after Claim 1 , characterized in that the at least one emission control device is a lean NOx storage (15). Setup after Claim 1 characterized in that the at least one emission control device is a three way catalyst (14) and a lean NOx storage (15). Setup after Claim 3 characterized in that the lean NOx trap (15) is located downstream of the three way catalyst (14). Setup after Claim 3 or 4 , characterized in that the three-way catalyst (14) and the lean NOx storage (15) are housed in a common housing (22). Furnishing according to one of the Claims 1 to 5 , characterized in that the exhaust gas cooler (13, 313, 413) is mounted in the wastegate passage (316, 424). Furnishing according to one of the Claims 1 to 6 characterized in that the wastegate passage (316, 424) is formed by a separate tube having an inlet end operatively connected to the upstream of the turbine (351, 451) and an outlet end connected downstream of the turbine (351, 451). Furnishing according to one of the Claims 1 to 7 characterized in that the wastegate valve (402) is used to control the flow of exhaust gases through the wastegate duct (316, 424). Setup after Claim 8 Characterized in that a boost pressure control valve (402) is operable to exhaust only through the Ladruckregel channel (316, 424) to flow when predetermined engine operating conditions exist. Furnishing according to one of the Claims 1 to 5 characterized in that the wastegate duct (316, 424) has an inlet end upstream of the turbine (351, 451) and an outlet end downstream of the turbine (351, 451), the exhaust gas cooler (13, 313, 413) downstream of the turbine (13). 351, 451) of the turbocharger (20, 320, 420) is mounted and a bypass channel (417) is provided to bypass the exhaust gas cooler (13, 313, 413) purposefully. Setup after Claim 10 characterized in that a wastegate valve (402) is used to control the flow of exhaust gases through the wastegate passage (316, 424), and a bypass valve (412) is used to control the flow of exhaust gases to control the bypass channel (417). Setup after Claim 11 characterized in that when the engine (10) is operating at high load, the bypass valve (412) is operated to close the by-pass passage (417) so that substantially all of the exhaust gases are exhausted through the exhaust cooler (13, 313) , 413) flow. Setup after Claim 11 or 12 characterized in that the bypass valve (412) is controlled to control the temperature of the exhaust gases flowing to the at least one emission control device, at least during operation of the engine (10) in the lean combustion mode. Internal combustion engine, which is operable in at least one lean combustion mode, wherein the engine (10) has an emission control device operatively connected thereto according to one of the Claims 1 to 13 for receiving exhaust gases from the engine (10).

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