阅读说明：本技术 废气再处理系统以及用于内燃机的废气再处理的方法 (Exhaust gas aftertreatment system and method for exhaust gas aftertreatment of an internal combustion engine ) 是由 B.赫普费尔德 F-C.巴龙冯塞乌默恩-林登斯特杰纳 S.波克纳 于 2018-06-14 设计创作，主要内容包括：本发明涉及一种用于按照汽油机原理的外源点火的内燃机的废气再处理系统。内燃机在排气口侧与废气设备连接,其中,在废气设备中沿废气通过废气设备的流动方向布置有可电加热的三元催化器,在所述可电加热的三元催化器下游布置有四元催化器,在所述四元催化器的下游布置有另外的三元催化器。在内燃机起动之前,可电加热的三元催化器和优选甚至四元催化器也被加热,以便从内燃机起动起就实现内燃机的未处理排放的有效的废气再处理。废气再处理系统此外设置为,甚至在四元催化器的再生期间也实现有害物质的有效转化,并且以此在机动车的所有运行情况中都保证特别低的排放。(The invention relates to an exhaust gas aftertreatment system for an internal combustion engine ignited from an external source according to the principle of a gasoline engine. The internal combustion engine is connected on the exhaust-gas outlet side to an exhaust-gas system, wherein an electrically heatable three-way catalyst is arranged in the exhaust-gas system in the flow direction of the exhaust gases through the exhaust-gas system, a four-way catalyst is arranged downstream of the electrically heatable three-way catalyst, and a further three-way catalyst is arranged downstream of the four-way catalyst. Before the internal combustion engine is started, the electrically heatable three-way catalyst and preferably even the four-way catalyst are also heated in order to achieve effective exhaust gas aftertreatment of the untreated emissions of the internal combustion engine from the start of the internal combustion engine. The exhaust gas aftertreatment system is furthermore designed to achieve an effective conversion of pollutants even during the regeneration of the quaternary catalyst and thus to ensure particularly low emissions in all operating situations of the motor vehicle.)

1. An exhaust gas aftertreatment system for an internal combustion engine (10) fired by external energy, wherein an electrically heatable three-way catalyst (24) close to the engine is arranged downstream of an exhaust gas outlet (12) of the internal combustion engine (10) in an exhaust gas system (20) connected to the exhaust gas outlet (12), a four-way catalyst (28) is arranged downstream of the electrically heatable three-way catalyst (24), and a further three-way catalyst (32) is arranged downstream of the four-way catalyst (28), wherein the exhaust gas system (20) is assigned a secondary air system (62) by means of which secondary air can be blown into or into the exhaust gas system (20) of the internal combustion engine (10) upstream of the electrically heatable three-way catalyst (24).

2. Exhaust gas aftertreatment system according to claim 1, characterized in that a burner (30) is arranged in the exhaust gas system (20) downstream of the electrically heatable three-way catalyst (24) and upstream of the four-way catalyst (28), by means of which burner the four-way catalyst (28) can be heated.

3. An exhaust gas aftertreatment system according to claim 1 or 2, characterized in that an HC adsorber (26) is arranged in the exhaust gas system (20) downstream of the electrically heatable three-way catalyst (24) and upstream of the four-way catalyst (28).

4. Exhaust gas aftertreatment system according to one of the claims 1 to 3, characterized in that the secondary air system (62) comprises a secondary air pump (34) and a secondary air valve (38), wherein the secondary air valve (38) is arranged on the cylinder head (14) of the internal combustion engine (10) on the exhaust port side.

5. Exhaust gas aftertreatment system according to claim 2 and claim 4, characterized in that the secondary air pump (34) is connected to the burner (30) via a secondary air line (42) and a second secondary air valve (64).

6. Exhaust gas aftertreatment system according to claim 2 and claim 4, characterized in that a second secondary air pump (40) is provided, by means of which fresh air can be supplied to the burner (30).

7. An exhaust gas aftertreatment system according to claim 2, characterized in that a first temperature sensor (54) is arranged downstream of a connection (52) of the burner (30) with an exhaust gas channel (60) of the exhaust gas apparatus (20) and upstream of the quaternary catalyst (28), and a second temperature sensor (56) is arranged downstream of the quaternary catalyst (28).

8. Exhaust gas aftertreatment system according to one of claims 1 to 7, characterized in that a lambda sensor (44, 46, 48, 50) is arranged in the exhaust gas duct (60) upstream and downstream of the electrically heatable three-way catalyst (24) and upstream and downstream of the four-way catalyst (28), respectively, wherein the lambda sensor (44, 46, 48, 50) is designed as a water-impact-resistant, electrically heatable lambda sensor (44, 46, 48, 50).

9. A method for the exhaust-gas aftertreatment of an internal combustion engine (10) having an exhaust-gas aftertreatment system, wherein an electrically heatable three-way catalyst (24) close to the engine is arranged downstream of the exhaust outlet (12) in an exhaust-gas system (20) connected to the exhaust outlet (12) of the internal combustion engine (10), a four-way catalyst (28) is arranged downstream of the electrically heatable three-way catalyst (24), and a further three-way catalyst (32) is arranged downstream of the four-way catalyst (28), wherein a burner (30) is arranged downstream of the electrically heatable three-way catalyst (24) and upstream of the four-way catalyst (28), by means of which burner the four-way catalyst (28) can be heated, characterized in that, before the start-up of the internal combustion engine (10) or from the start-up of the internal combustion engine, the heating of the electrically heatable three-way catalyst (24) is initiated by a trigger signal of a signal transmitter and the burner (30) is activated in order to heat the electrically heatable three-way catalyst (24) and the four-way catalyst (28) to the light-off temperature as quickly as possible.

10. The method for exhaust gas aftertreatment of an internal combustion engine according to claim 9, characterized in that the signal transmitter is a door contact switch, a sensor for seat occupancy, a receiver of a keyless switching system, a seatbelt buckle sensor or a control device of a hybrid vehicle.

Examples

Fig. 4 shows a further exemplary embodiment of an exhaust gas aftertreatment system according to the invention for an internal combustion engine with external ignition, in which the burner and the exhaust port are supplied with fresh air by a common secondary air pump.

FIG. 5 shows a further embodiment of a preferred exhaust gas aftertreatment system according to the invention, in which the exhaust ports of the burner and the internal combustion engine are supplied with fresh air by means of two secondary air valves by means of a common secondary air pump;

fig. 6 shows a flow diagram for heating the exhaust gas aftertreatment system before and during a cold start of the internal combustion engine.

A first embodiment of an exhaust gas aftertreatment system for an internal combustion engine 10 according to the invention is shown in fig. 1. The internal combustion engine 10 is designed as an externally ignited internal combustion engine 10, preferably as an internal combustion engine 10 which is ignited externally by means of a spark plug 16 according to the gasoline engine principle. Here, an exhaust system 20 is connected to the exhaust outlet 12 of the internal combustion engine 10. In the exhaust apparatus 20, a turbine 22 of the exhaust turbocharger device 18 is arranged downstream of the exhaust port 12 of the internal combustion engine 10 in the flow direction of the exhaust gas flowing through the exhaust apparatus 20, and an electrically heatable three-way catalyst 24 close to the engine is arranged downstream of the turbine 22. The electrically heatable three-way catalytic converter 24 has an electrical heating element, preferably an electrical heating plate 66, the electrical heating plate 66 preferably being arranged on the inlet side at the electrically heatable three-way catalytic converter 24. Downstream of the electrically heatable three-way catalyst 24, a four-way catalyst 28, i.e. a particle filter with a three-way catalytically active coating, is arranged, and further downstream, a further three-way catalyst 32 is arranged. A secondary air system 62 having a secondary air pump 34 is provided on the exhaust system 20, fresh air being introduced into the exhaust gas duct 60 of the exhaust system 20 by means of the secondary air pump 34 via a first secondary air valve 38 upstream of the electrically heatable three-way catalyst 24 in a first introduction position and via a second air valve 64 downstream of the electrically heatable three-way catalyst 24 and upstream of the four-way catalyst 28 in a second introduction position. The two secondary air valves 38, 64 communicate with the secondary air pump 34 through the two secondary air lines 36, 42. Upstream of the electrically heatable three-way catalyst 24, a first lambda sensor 44, preferably of the broadband type, is arranged, with which the combustion air ratio lambda of the internal combustion engine 10 can be adjusted. Downstream of the electrically heatable three-way catalytic converter 24 and upstream of the second secondary air valve 64, a second lambda sensor 46, in particular a step-change lambda sensor, is arranged in the exhaust gas duct 60 in order to correct errors in the adjustment of the air ratio with the broadband lambda sensor 44 and to ensure proper functioning of the electrically heatable three-way catalytic converter 24. Downstream of the second insertion point and upstream of the quaternary catalyst 28, a third lambda sensor 48, in particular a further lambda sensor of the broadband type, is arranged in order to determine the proportion of exhaust gas air flowing to the quaternary catalyst 28, in particular when fresh air is blown into the exhaust gas duct 60 by means of the second secondary air valve 64. Downstream of the quaternary catalyst 28, a fourth lambda sensor 50, in particular a further lambda sensor of the jump type, is arranged in order to check the function of the quaternary catalyst 28. Downstream of the second secondary air valve 64 and upstream of the quaternary catalyst 28, a first temperature sensor 54 is arranged in the exhaust gas duct 60, with which the inlet temperature of the exhaust gas can be determined before it enters the quaternary catalyst 28. Downstream of the four-way catalyst 28 and upstream of the further three-way catalyst 32, a further temperature sensor 56 is provided, with which further temperature sensor 56 the exhaust gas temperature downstream of the four-way catalyst 28 can be determined. The exhaust gas aftertreatment system furthermore has a control device 58, in particular a control device 58 of the internal combustion engine 10, by means of which control device 58 the signals of the lambda sensors 44, 46, 48, 50 and the signals of the temperature sensors 54, 56 can be processed and the combustion air ratio lambda of the internal combustion engine 10, in particular the fuel quantity, and the amount of secondary air supplied to the exhaust gas duct 60 by means of the secondary air valves 38, 64 can be regulated.

Fig. 2 shows a preferred exemplary embodiment of an exhaust gas aftertreatment system according to the invention for an internal combustion engine 10 with external ignition. In the exhaust gas system 20 of the internal combustion engine 10, in the flow direction of the exhaust gas of the internal combustion engine 10 through the exhaust gas system 20, an electrically heatable three-way catalyst 24 close to the engine, an HC adsorber 26 downstream of the electrically heatable three-way catalyst 24, a four-way catalyst 28 further downstream, and a further three-way catalyst 32 downstream of the four-way catalyst 28 are arranged. The electrically heatable three-way catalyst 24 can be heated by the heater chip 66. The quaternary catalyst 28 can be heated by the burner 30, the burner 30 communicating with an exhaust gas passage 60 of the exhaust gas system 20 downstream of the HC adsorber 26 and upstream of the quaternary catalyst 28 at the communication portion 52. The exhaust gas aftertreatment system further includes a secondary air system 62 having a first secondary air pump 34 in communication with the cylinder head 14 of the internal combustion engine 10 via a first secondary air line 36. Through the first secondary air line 36, fresh air can be introduced into the hot exhaust gases in the region of the exhaust port 12 immediately downstream of the exhaust valve of the internal combustion engine 10 in order to contribute to the exothermic conversion of the unburned fuel components. An exhaust-gas turbocharger device 18 having a turbine 22 can be arranged in the exhaust system 20, preferably upstream of an electrically heatable three-way catalyst 24. A first lambda sensor 44, preferably a broadband lambda sensor, is arranged directly upstream of the electrically heatable three-way catalyst 24, with which the combustion air ratio lambda flowing to the electrically heatable three-way catalyst 24 can be determined. A further lambda sensor 46, in particular a transition lambda sensor, is arranged directly downstream of the electrically heatable three-way catalyst 24, with which the function of the electrically heatable three-way catalyst 24 can be monitored and a high-concentration breakthrough (fettdurchbrucch) or a low-concentration breakthrough (magerdurchbrucch) to the electrically heatable three-way catalyst 24 can be detected.

In addition, the secondary air system 62 has a second secondary air pump 40 which is connected via a second secondary air line 42 to a secondary air valve 64 at the burner 30. A third lambda sensor 48 and a first temperature sensor 54 are provided directly upstream of the quaternary catalytic converter 28, with which third lambda sensor 48 and first temperature sensor 54 the exhaust gas air ratio is determined when the quaternary catalytic converter 28 is flushed and the burner 30 can be controlled accordingly. Downstream of the four-way catalyst 28, a fourth lambda sensor 50 and a second temperature sensor 56 are provided.

Fig. 3 shows a further exemplary embodiment of an exhaust gas aftertreatment system according to the invention for an internal combustion engine 10. In the case of a structure which is substantially the same as that of fig. 1, only the differences with respect to the first embodiment will be described below. The secondary air pump 34 communicates via a secondary air line 36 with the cylinder head 14 of the internal combustion engine 10, on which a secondary air valve 38 is arranged, with which secondary air is blown into the cylinder head on the outlet side directly downstream of the outlet valve of the internal combustion engine 10. Downstream of the electrically heatable three-way catalyst 24 and upstream of the four-way catalyst 28, there is additionally arranged an HC adsorber with which unburned hydrocarbons are temporarily stored when the exhaust gas is cold and are released again to the exhaust gas when the exhaust gas is hot. A second secondary air pump 40 is also provided, which second secondary air pump 40 communicates via a second secondary air line 42 with a second secondary air valve 64, wherein the second secondary air valve 64 communicates with an inlet point via which fresh air is blown into the exhaust gas duct 60 downstream of the HC adsorber 26 and upstream of the quaternary catalyst 28.

Fig. 4 shows a further exemplary embodiment of an exhaust gas aftertreatment system according to the invention for an internal combustion engine 10. In the case of a construction which is essentially identical to that of fig. 2, only the differences with respect to the preferred embodiment shown in fig. 2 will be described below. In contrast to the exemplary embodiment in fig. 2, the HC adsorber downstream of the electrically heatable three-way catalyst 24 and upstream of the four-way catalyst 28 is omitted in this exemplary embodiment. This is possible because the electrically heatable catalyst 24 can be heated up before the internal combustion engine 10 is started, and the quaternary catalyst 28 can be heated up to the light-off temperature very quickly by the burner 30 after the internal combustion engine is started. Thus, the hydrocarbon difference is kept small. In addition, in this exemplary embodiment, a common secondary air pump 34 is provided for blowing secondary air into the cylinder head 14 and for supplying fresh air to the burner 30. To this end, the secondary air pump 34 is connected via a first secondary air line 36 to a first secondary air valve 38 at the cylinder head 14 of the internal combustion engine 10 and via a second secondary air line 42 to a second secondary air valve 64 on the burner 30. By means of the secondary air pump 34, the electrically heatable catalytic converter 24 can be flowed through by the volume flow just before the internal combustion engine 10 is started, and thus the heating of the electrically heatable catalytic converter 24 is assisted.

Fig. 5 shows a further preferred embodiment of an exhaust gas aftertreatment system according to the invention for an internal combustion engine 10. In this exemplary embodiment, essentially the same construction as in fig. 2, only one secondary air pump 34 is provided, which secondary air pump 34 is connected to the cylinder head 14 of the internal combustion engine 10 via a first secondary air line 36 and a first secondary air valve 38. The secondary air can thus be introduced into the exhaust port 12 of the internal combustion engine 10 directly downstream of the exhaust valve. The secondary air pump 34 is connected to the burner 30 via the second secondary air line 42 and the second secondary air valve 64, so that the burner 30 is likewise supplied with fresh air via the secondary air pump 34 and the combustion air ratio of the burner 30 can be adjusted. Here, the air quantity adjustment is preferably effected by adjustment of the secondary air pump 34. Furthermore, the oxygen required for regenerating the soot remaining in the quaternary catalyst 28 may be provided via the second secondary air line 42 and the burner 30, so that a controlled burnout of the soot on the quaternary catalyst 28 does not risk thermal damage to the quaternary catalyst 28.

Fig. 6 shows a method according to the invention for the exhaust gas aftertreatment of an internal combustion engine 10. In a first method step <110>, the electrical heating of the heating disk 66 of the electrically heatable three-way catalyst 24 can be started in a pre-start phase <100 >. Alternatively, it can also be carried out in conjunction with the starting of the internal combustion engine 10. The warm-up phase <100> is triggered as described below by a signal transmitter, for example a door contact switch or a trigger signal of a control device of the hybrid drive. At the same time, fresh air can be blown into the exhaust gas system 20 upstream of the electrically heatable three-way catalyst 24 by means of the secondary air pump 34, in order to form an air flow through the exhaust gas system 20 when the internal combustion engine 10 is shut down and to achieve convective heat transfer from the heater disk 66 to the other parts of the electrically heatable catalyst 24. Alternatively, preheating of the electrically heatable three-way catalyst 24 without secondary air introduction is also possible. At the same time, in method step <120>, the lambda sensors 44, 46, 48, 50 can be heated and set to the operating temperature. Optionally, in method step <130>, hot gas is introduced into the exhaust system 20 upstream of the quaternary catalyst by means of the burner 30 in order to heat the quaternary catalyst, likewise before the engine of the internal combustion engine 10 is started. The blowing of the secondary air may be stopped with the start of the internal combustion engine 10. Alternatively, the electrically heatable three-way catalyst 24 is heated periodically, in particular in the case of a hybrid vehicle, so that the electrically heatable three-way catalyst 24 is always ready even in the case of an electric drive. It is therefore possible to effectively convert gaseous pollutant components immediately after the engine is started when there is a load demand on the internal combustion engine 10.

In the start phase <200>, the internal combustion engine 10 is started. Here, in method step <210>, the electrically heatable three-way catalyst 24 is controlled and the heating plate 66 is heated further until a threshold temperature is reached, which is preferably higher than the light-off temperature of the electrically heatable three-way catalyst 24. In a parallel method step <220>, the combustion air ratio λ is set to the stoichiometric combustion air ratio λ of 1 by a λ sensor even during cold starting, in order to keep untreated emissions as low as possible even during cold starting. At the same time, in method step <230>, the electrically heatable three-way catalytic converter 24 is continuously heated with delay by means of engine-related measures, for example by adjusting the ignition angle. Also simultaneously, in method step <240>, the quaternary catalyst 28 is heated by the burner 30 until the quaternary catalyst also reaches the threshold temperature. In this case, the burner 30 is preferably activated upon starting the internal combustion engine 10. When the exhaust gas is cold, unburned hydrocarbons are stored in the HC adsorber 26 in a further parallel method step <250 >. If the HC adsorber 26 has reached the threshold temperature, the unburned hydrocarbons stored in the HC adsorber 26 are discharged again in method step <260>, and the HC adsorber 26 is regenerated. If the start-up phase <200> is over and the catalytic converters 24, 28, 32 have reached their operating temperature, a transition is then made to normal operation <300 >. In normal operation <300>, the internal combustion engine 10 is operated in method step <310> with a substantially stoichiometric combustion air ratio λ of 1, in order to ensure optimum conversion of harmful exhaust gas constituents.

List of reference numerals

10 internal combustion engine

12 exhaust port

14 cylinder head

16 spark plug

18 turbo-charging device

20 waste gas equipment

22 turbine

24 electrically heatable three-way catalytic converter

26 HC adsorber

28 four-element catalyst

30 burner

32 three-way catalyst

34 (first) secondary air pump

36 secondary air pipeline

38 secondary air valve

40 (second) secondary air pump

42 (second) secondary air line

44 first lambda sensor

46 second lambda sensor

48 third lambda sensor

50 fourth lambda sensor

52 communication part

54 (first) temperature sensor

56 (second) temperature sensor

58 control device

60 exhaust line

62 Secondary air System

64 (second) secondary air valve

66 heating plate