METHOD FOR OPERATING AN EXHAUST GAS PURIFICATION APPARATUS

Abstract

A method for operating an exhaust gas purification apparatus (10) of a vehicle includes monitoring close-coupled lambda value (Ln) of a close-coupled catalytic converter apparatus (20), operating the close-coupled catalytic converter apparatus (20) with an excess of fuel, monitoring a non-close-coupled lambda value (Lf) of a non-close-coupled catalytic converter apparatus (30), and operating the non-close-coupled catalytic converter apparatus (30) in a stoichiometric method of operation.

Claims

1. A method for operating an exhaust gas purification apparatus of a vehicle, comprising: monitoring a close-coupled lambda value of a close-coupled catalytic converter apparatus, operating the close-coupled catalytic converter apparatus with an excess of fuel, monitoring a non-close-coupled lambda value of a non-close-coupled catalytic converter apparatus, and operating of the non-close-coupled catalytic converter apparatus in a stoichiometric method of operation.

2. The method of claim 1, further comprising feeding additional air and/or an additional air mixture to the non-close-coupled catalytic converter apparatus for the stoichiometric method of operation.

3. The method of claim 2, further comprising selectively cooling the exhaust gas stream between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus.

4. The method of claim 1, further comprising selectively cooling the exhaust gas stream between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus.

5. The method of claim 1, wherein the method is carried out only in part load operation and/or in starting operation of an internal combustion engine of the vehicle.

6. The method of claim 1, wherein the method is carried out only in full load operation of an internal combustion engine of the vehicle.

7. The method of claim 1, wherein the method is carried out only in part load operation of the internal combustion engine of the vehicle and when the close-coupled catalytic converter apparatus exceeds a limit temperature.

8. The method of claim 1, wherein the vehicle has an internal combustion engine with first and second cylinder sections coupled respectively to first and second close-coupled catalytic converter apparatuses that are operated to have complementary lambda values.

9. An exhaust gas purification apparatus for an internal combustion engine of a vehicle, comprising at least one close-coupled catalytic converter apparatus, a non-close-coupled catalytic converter apparatus, a close-coupled sensor unit for monitoring close-coupled lambda values of the close-coupled catalytic converter apparatus, a non-close-coupled sensor unit for monitoring non-close-coupled lambda values of the non-close-coupled catalytic converter apparatus, and a control module for selectively operating the close-coupled catalytic converter apparatus with an excess of fuel and for selectively operating the non-close-coupled catalytic converter apparatus in a stoichiometric method of operation.

10. The exhaust gas purification apparatus of claim 9, further comprising a gas inlet between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus for the inlet of additional air and/or an additional air mixture, the gas inlet being connected to a pumping apparatus and/or a gas source.

11. The exhaust gas purification apparatus of claim 11, further comprising a cooling apparatus between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus for cooling the exhaust gas stream from the close-coupled catalytic converter apparatus to the non-close-coupled catalytic converter apparatus.

12. The exhaust gas purification apparatus of claim 11 further comprising at least one additional sensor unit between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus for determining at least one intermediate lambda value.

13. The exhaust gas purification apparatus of claim 9, further comprising a cooling apparatus between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus for cooling the exhaust gas stream from the close-coupled catalytic converter apparatus to the non-close-coupled catalytic converter apparatus.

14. The exhaust gas purification apparatus of claim 9 further comprising at least one additional sensor unit between the close-coupled catalytic converter apparatus and the non-close-coupled catalytic converter apparatus for determining at least one intermediate lambda value.

15. The exhaust gas purification apparatus of claim 9, wherein the internal combustion engine has first and second cylinder sections, the at least one close-coupled catalytic converter apparatus comprising first and second close-coupled catalytic converter apparatuses communicating respectively with the first and second cylinder sections, the control module operating the first and second close-coupled catalytic converter apparatuses with opposed complementary lambda values.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a first embodiment of an exhaust gas purification apparatus according to the invention.

[0029] FIG. 2 shows a further embodiment of an exhaust gas purification apparatus according to the invention.

[0030] FIG. 3 shows a further embodiment of an exhaust gas purification apparatus according to the invention.

[0031] FIG. 4 shows a further embodiment of an exhaust gas purification apparatus according to the invention.

[0032] FIG. 5 shows a further embodiment of an exhaust gas purification apparatus according to the invention.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a particularly simple refinement of an exhaust gas purification apparatus 10 according to the invention. Here, the internal combustion engine 100 is shown with a single cylinder section 110 with four individual cylinders which are shown diagrammatically here. A common collecting line is provided at the outlets of the individual cylinders of the cylinder section 110 and introduces the exhaust gas stream either via a diagrammatically shown wastegate valve or an exhaust gas turbine into the close-coupled catalytic converter apparatus 20. A close-coupled sensor unit 22 is provided for monitoring the close-coupled lambda value Ln. Starting from the outlet downstream of the close-coupled catalytic converter apparatus 20. The exhaust gas stream is introduced after this first treatment into a non-close-coupled catalytic converter apparatus 30 to subject the exhaust gas stream to final treatment and purification. A non-close-coupled sensor unit 32 is situated here to monitor the non-close-coupled lambda value Lf.

[0034] A control module 40 can operate the close-coupled catalytic converter apparatus 20 with an excess of fuel and the non-close-coupled catalytic converter apparatus 30 in a stoichiometric operating method by way of the input values of the close-coupled lambda value Ln and the non-close-coupled lambda value Lf. This allows a reduction of the thermal loading of the close-coupled catalytic converter apparatus 20 and more rapid heating of the non-close-coupled catalytic converter apparatus 30.

[0035] FIG. 2 shows an alternate configuration of the embodiment of FIG. 1 where a cooling apparatus 60 is provided to reduce the thermal loading of the non-close-coupled catalytic converter apparatus 30 even in full load operation. This allows the exhaust gas stream to be cooled in an active or passive way in the case of the transfer from the close-coupled catalytic converter apparatus 20 into the non-close-coupled catalytic converter apparatus 30.

[0036] FIG. 3 shows an alternate configuration of the embodiment of FIG. 2 where a gas inlet 50 is provided between the two catalytic converter apparatuses 20 and 30 for introducing an additional gas, in particular air or an air mixture, into the exhaust gas stream. The mixing is possible via a pumping apparatus 52. Moreover, two additional sensor units 56 allow intermediate lambda values Lz to be made available and to be forwarded to the control module 40 for evaluation and use of the control.

[0037] FIG. 4 shows one embodiment of the internal combustion engine 100 with first and second separate cylinder sections 110, each of which has four cylinders. The first and second cylinder sections 110 respectively produce first and second exhaust gas streams that are conducted in each case either via the wastegate valve or the associated turbine to respective first and second separate and specifically associated close-coupled catalytic converter apparatuses 20. Subsequently, the exhaust gas stream can be combined downstream of the first and second close-coupled catalytic converter apparatuses 20, and can be fed to a common non-close-coupled catalytic converter apparatus 30. A control module 40 also is provided for carrying out the method of the invention. Care is taken in this embodiment for monitoring of the close-coupled lambda values Ln so that, for example, the upper of the two close-coupled catalytic converter apparatuses 20 is operated with a rich operating mixture and the lower of the two close-coupled catalytic converter apparatuses 20 is operated with a correspondingly leaner operating mixture. This leads to the two close-coupled catalytic converter apparatuses 20 being operated in a complementary lambda operating method with respect to the above-described stoichiometric equalization in the exhaust gas stream for the non-close-coupled catalytic converter apparatus 30. Thus, a separate pumping apparatus 52 or an associated gas inlet 50 are no longer necessary to increase the flexibility for the stoichiometry.

[0038] FIG. 5 shows an alternate configuration of the embodiment of FIG. 4 and includes a cooling apparatus 60 that can be of identical configuration to the cooling apparatus described with reference to FIGS. 2 and 3. A total of three additional sensor units 56 for corresponding recording of additional intermediate lambda values Lz are also shown here.

[0039] The above description of the embodiments describes the present invention exclusively within the context of examples. However, individual features of the embodiments can be combined freely with one another, in so far as technically appropriate, without departing from the scope of the invention.