Problem detection apparatus and method in exhaust purifying apparatus

Abstract

An exhaust purifying apparatus is provided with a filter located in an exhaust path of an internal combustion engine and configured to collect particulates in exhaust gas. The exhaust purifying apparatus is also provided with a differential pressure sensor which detects the pressure difference generated between the upstream side and downstream side of the filter. The problem detection apparatus of the exhaust purifying apparatus is provided with a differential pressure calculation unit and a judgment unit. The differential pressure calculation unit calculates the pressure difference between the upstream and downstream sides of the filter based on the operating state of the internal combustion engine. The judgment unit calculates a difference P between an actual measurement value of the pressure difference and a calculation differential pressure value compares the difference P with a threshold value, and detects that the filter has a problem.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a Continuation application of PCT Application No. PCT / JP2007 / 074106, filed Dec. 14, 2007, which was published under PCT Article 21 (2) in Japanese.[0002]This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2006-350134, filed Dec. 26, 2006, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The present invention relates to a problem detection apparatus and method in an exhaust purifying apparatus, in an exhaust filtering system such as a DPF.[0005]2. Description of the Related Art[0006]An exhaust filtering system such as a diesel particulate filter (DPF) system has a filter inside for collecting particulates included in exhaust gas of an engine, and purifies the exhaust gas through the filter. A filter is clogged with collected particulates. Therefore, appropriate amount of the collected particulate...

AI Technical Summary

Benefits of technology

[0026]A problem detection apparatus and method in an exhaust filtering system according to the present invention has the following effects.

[0027]A filter problem can be detected by calculating a calculation differential pressure value even in an unsteady traveling state. As a threshold value is sequentially calculated from a traveling state, a filter problem can be detected by comparing with a threshold value even in an unsteady traveling state.

[0028]A soot deposition value is calculated by considering a loss caused by Nox and heat, and a threshold value is corrected based on such a soot deposition value. Therefore, the calculated value reflects an actual driving history, and a problem can be detected by using an appropriate threshold value.

[0029]An ash deposition value is calculated by using a total fuel injection amount, and the calculated value reflects an actual driving history more than in a case of calculation based on a traveling distance.

[0030]A clogging of a filter and a leak caused by a crack can be detected. As a filter problem is checked after a lapse of certain time, the reliability of the problem detection apparatus can be increased.

[0031]FIG. 1 is a diagram showing the configuration of an engine having an embodiment of a problem detection apparatus according to the present invention;

Problems solved by technology

There are following problems in a conventional problem detection apparatus for a particulate filter.

Thus, a diagnosis is not executed.

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