Internal combustion engine and method for operating same

Patent metadata

Field	Value
Publication number	US-10876449-B2
Application number	US-201615548298-A
Country	US
Kind code	B2
Filing date	Feb 4, 2016
Priority date	Feb 5, 2015
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

Method for operating an internal combustion engine which has a gas combustion system and an exhaust gas post-treatment system. Exhaust gas that leaves the gas combustion system is directed to at least one CH4 oxidation catalytic converter of the exhaust gas post-treatment system. The CH4/NO2 mole ratio in the exhaust gas is set in a defined fashion by at least one gas-combustion-system-side and/or exhaust-gas-post-treatment-system-side measure upstream of at least one CH4 oxidation catalytic converter.

First claim

The invention claimed is:

1. A method for operating an internal combustion engine, having a gas combustion system and an exhaust gas aftertreatment system, comprising:
conducting an exhaust gas, which leaves the gas combustion system, via the exhaust gas aftertreatment system having at least one CH 4 -oxidation catalytic converter for cleaning;
determining an actual NO 2 exhaust gas value based at least in part on a measured value;
measuring a CH 4 /NO 2 mole ratio in the exhaust gas at least one of on a gas combustion system side and on an exhaust gas aftertreatment system side upstream of the at least one CH 4 -oxidation catalytic converter;
adjusting a CH 4 /NO 2 mole ratio in the exhaust gas based at least in part on the measurement to be less than or equal to 2.

2. The method according to claim 1 , further comprising:
adjusting an NO 2 proportion in the exhaust gas is adjusted so that upstream of the at least one CH 4 -oxidation catalytic converter the NO 2 proportion of a total nitrogen oxides in the exhaust gas amounts to at least one of:
at least 15%,
at least 30%, and
at least 50%.

3. The method according to claim 2 , wherein the NO 2 proportion in the exhaust gas is adjusted via at least one NO-oxidation catalytic converter of the exhaust gas aftertreatment system, which is arranged upstream of the at least one CH 4 -oxidation catalytic converter.

4. The method according to claim 3 , wherein the exhaust gas is conducted via a plurality of CH 4 -oxidation catalytic converters which are positioned one after the other and upstream of at least one CH 4 -oxidation catalytic converters via at least one NO— oxidation catalytic converter.

5. The method according to claim 2 , wherein the NO 2 proportion in the exhaust gas is adjusted by changing at least one operating parameter for the gas combustion system.

6. The method according to claim 5 , wherein the at least one operating parameter comprises at least one of a lambda value, an ignition timing, valve control times, an engine compression, and an exhaust gas proportion in an engine combustion chamber.

7. The method according to claim 5 , further comprising:
changing the at least one operating parameter for the gas combustion system such that the actual NO 2 exhaust gas value is approximated to an NO 2 exhaust gas set point value.

8. The method according to claim 1 , further comprising:
conducting the exhaust gas upstream of the at least one CH 4 -oxidation catalytic converter is conducted via an SCR-catalytic converter; and
introducing at least one of NH 3 or an NH 3 precursor substance in the exhaust gas downstream of the SCR-catalytic converter.

9. An internal combustion engine, comprising:
a gas combustion system;
a sensor configured to measure an actual NO 2 exhaust gas value, and
an exhaust gas aftertreatment system, that comprises at least one CH 4 -oxidation catalytic converter,
wherein an NO 2 proportion in the exhaust gas is adjusted in a defined manner by at least one of:
at least one measure on a gas combustion system side and
at least one measure on an exhaust gas aftertreatment system side; and
an engine control device configured to receive a measured a CH 4 /NO 2 mole ratio in the exhaust gas and adjusting a CH 4 /NO 2 mole ratio in the exhaust gas to be less than or equal to 2 based at least in part on the received measurement.

10. The internal combustion engine according to claim 9 , further comprising:
an NO-oxidation catalytic converter arranged upstream of the at least one CH 4 -oxidation catalytic converter.

11. The internal combustion engine according to claim 10 , wherein the exhaust gas aftertreatment system comprises a plurality of CH 4 -oxidation catalytic converters connected one behind the other, wherein upstream of at least one of the plurality of CH 4 -oxidation catalytic converters at least one NO-oxidation catalytic converter is arranged.

12. The internal combustion engine according to claim 10 , further comprising:
an exhaust gas turbocharger,
wherein at least one NO-oxidation catalytic converter is positioned upstream of a turbine of the exhaust gas turbocharger.

13. The internal combustion engine according to claim 9 , further comprising:
an SCR-catalytic converter arranged downstream of the at least one CH 4 -oxidation catalytic converter; and
a device positioned upstream of the SCR-catalytic converter and configured to introduce at last one of NH 3 and an NH 3 precursor substance into the exhaust gas.

14. The internal combustion engine according to claim 9 ,
wherein the sensor configured to determine an actual NO 2 exhaust gas value is at least one of downstream of the gas combustion system and upstream of the exhaust gas aftertreatment system; and
the engine control device further configured to change at least one operating parameter for the gas combustion system such that the actual NO 2 exhaust gas value is approximated to an NO 2 exhaust gas set point value.

15. The internal combustion engine according to claim 14 , wherein the engine control device determines the NO 2 exhaust gas set point value as a function of at least one operating parameter of the gas combustion system.

16. The method according to any one of the claim 1 , wherein the CH 4 /NO 2 mole ratio in the exhaust gas is smaller than 1.5.

17. The method according to any one of the claim 1 , wherein the CH 4 /NO 2 mole ratio in the exhaust gas is smaller than 1.

18. The internal combustion engine according to claim 14 , wherein the engine control device determines the NO 2 exhaust gas set point value based at least in part on a load point.

19. The internal combustion engine according to claim 9 , wherein the received CH 4 /NO 2 mole ratio in the exhaust gas is from at least one of on a gas combustion system side and on an exhaust gas aftertreatment system side upstream of the at least one CH 4 -oxidation catalytic converter.

Assignees

• Man Diesel & Turbo Se
• Man Energy Solutions Se

Inventors

• Döring Andreas
• Toshev Plamen

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F01N2900/1402

  Exhaust gas composition · CPC title

• F01N2570/14

  Nitrogen oxides · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• F01N3/103 Primary

  Oxidation catalysts for HC and CO only · CPC title