Device for monitoring an exhaust gas catalytic converter for an internal combustion engine

Abstract

A device for monitoring an exhaust gas catalytic converter in the exhaust system of an internal combustion engine, includes a measuring apparatus that is arranged in the exhaust system in such a way that, in the greatest part of the operating range of the internal combustion engine, it assumes a temperature that is correlated with a temperature of the exhaust gas catalytic converter. The measuring apparatus has a temperature-sensitive component with a temperature-dependent characteristic component parameter that changes either abruptly at a predetermined transition temperature or temperature range, or continuously in a predetermined way as a function of the temperature. A control and evaluation unit connected to the measuring arrangement detects the characteristic component parameter and / or a change in the latter, and correlates it with an aging state of the exhaust gas catalytic converter.

Description

[0001]This application is a national stage of PCT Application No. PCT / EP2007 / 002989, filed Apr. 3, 2007, which claims priority under 35 U.S.C. §119 to German Patent Application No. 10 2006 016 906.9, filed Apr. 11, 2006, the entire disclosure of which is herein expressly incorporated by reference.BACKGROUND AND SUMMARY OF THE INVENTION[0002]The invention relates to a device for monitoring an exhaust gas catalytic converter in the exhaust system of an internal combustion engine. In particular, the invention relates to such a monitoring device having a measuring arrangement which is disposed in the exhaust system in such a way that, at least in the predominant part of the operating range of the internal combustion engine, it assumes a temperature correlated with a temperature of the exhaust gas catalytic converter.[0003]Exhaust gas catalytic converters may partially or completely lose their effectiveness when they are exposed to high temperatures. In this context, temperature loads ha...

AI Technical Summary

Benefits of technology

[0008]One object of the invention, therefore, is to provide a device which reliably monitors an exhaust gas catalytic converter in as simple a way as possible.

[0011]Thus, by means of the device according to the invention, essentially the cause of thermal damage is determined, more reliably and in a less complicated manner.

[0015]As a result of this embodiment, the measuring apparatus cannot be separated non-destructively from the exhaust gas catalytic converter or from the housing of the exhaust gas catalytic converter. The housing and measuring apparatus or the catalytic converter and measuring apparatus thus form a unit which cannot be separated non-destructively. Misinterpretations of the information delivered by the measuring arrangement as a result of an intended or unintended separation of the measuring arrangement from the exhaust gas catalytic converter are thus prevented. This achieves particularly high reliability in the assignment of data which are provided by the measuring arrangement.

[0016]In a further embodiment of the invention, the change in the characteristic component parameter is irreversible. Once it has occurred, therefore, the change can be detected unequivocally, so that interpretation difficulties are avoided.

[0019]In a further refinement of the invention, the temperature-sensitive component is produced by thick-film technology. This embodiment allows a substantial miniaturization, along with a flat set-up, resulting in simple and flexible installation possibilities and in good heat transmission.

Problems solved by technology

Exhaust gas catalytic converters may partially or completely lose their effectiveness when they are exposed to high temperatures.

However, the catalytic converter action often cannot be determined with the desired reliability in this way.

Moreover, the corresponding monitoring methods and devices for catalytic converter monitoring are often complicated.

As a result of this embodiment, the measuring apparatus cannot be separated non-destructively from the exhaust gas catalytic converter or from the housing of the exhaust gas catalytic converter.

In this case, other diagnostic devices often encounter installation problems due to space limitations.

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