Method for monitoring a methane oxidation catalyst and exhaust aftertreatment device

A technology for exhaust gas post-treatment and methane oxidation, which is applied in the electronic control of exhaust gas treatment devices, diagnostic devices of exhaust gas treatment devices, and exhaust gas treatment, etc. It can solve problems such as less characteristic and difficult monitoring.

Inactive Publication Date: 2017-10-20
ROBERT BOSCH GMBH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, such monitoring is generally difficult in the case of methane oxidation catalysts, since the change in the exothermic value during the conversion of methane in the methane oxidation catalyst due to the mild temperature behavior of said methane oxidation catalyst is not stable. too characteristic

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  • Method for monitoring a methane oxidation catalyst and exhaust aftertreatment device
  • Method for monitoring a methane oxidation catalyst and exhaust aftertreatment device
  • Method for monitoring a methane oxidation catalyst and exhaust aftertreatment device

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Embodiment Construction

[0024] figure 1 Shows methane shift and MOC NO in lean exhaust gas containing both NO and methane 2 -Formation of relationships between capabilities. Shown are methane conversions 10 , 20 , 30 as a function of temperatures between approximately 250° C. and 550° C. for three different catalyst states or three different MOCs. The profiles 10 , 20 , 30 represent, for example, catalytic converters aged to a different degree and / or suppressed by oxygen to a different degree, or the operating states of the catalytic converter at different space velocities. Variations 11, 21, 31 show NO in the exhaust leaving the corresponding MOC 2 / NO x -Proportion. From this it is evident that this MOC (Pd-rich catalytic converter) converts NO to NO within a defined range 2 . However, this NO 2 - Formation takes place only above the light-off temperature of the corresponding catalyst, that is to say above the temperature at which methane is converted on the required scale. As long as the m...

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Abstract

A method for monitoring a methane oxidation catalyst (420) in an exhaust pipe of an internal combustion engine (400) conducts activity diagnosis on the methane oxidation catalyst by means of NO2 in the methane oxidation catalyst (420). The method includes: deducing the methane conversion capability of the methane oxidation catalyst (420) through formation of NO2 and especially through a NO2- content and / or a proportion of NO2 / NOx- in or after the methane oxidation catalyst, and deducing the worsened methane conversion capability of the methane oxidation catalyst (420) through formation of possibly reduced NO2. In terms of determination of formation of NO2, an SCR-catalyst device (460) is preferably utilized, the SCR-catalyst device being positioned in parts of streams (450) of the exhaust pipe.

Description

technical field [0001] The invention relates to a method for monitoring a methane oxidation catalyst in an exhaust gas aftertreatment system of an internal combustion engine, an exhaust gas aftertreatment device as well as a computer program, a machine-readable storage medium and an electronic control unit , which are set up to implement the method. Background technique [0002] Internal combustion engines are known which can be operated not only with methane-containing gases, such as natural gas, or methane, but also with mixtures of the gas and another fuel, such as diesel fuel. With all approaches based at least in part on the combustion of methane-containing gases, the problem of high raw engine methane emissions arises. In particular for reasons of atmospheric protection, said methane emissions must be reduced within the framework of exhaust gas aftertreatment. Known are methane oxidation catalysts (MOCs) which oxidize the methane contained in the exhaust gas on the b...

Claims

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Application Information

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IPC IPC(8): F01N11/00F01N3/28G01N27/407
CPCF01N13/009F01N3/28F01N11/00G01N27/407F01N2570/12F01N2560/026F01N2900/1404F01N2550/02F01N3/2066Y02T10/12Y02T10/40F01N3/0814F01N3/10F01N3/20F02D19/0647
Inventor M.格勒克勒W.克里斯特尔
Owner ROBERT BOSCH GMBH
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