Exhaust emission control device and internal combustion engine equipped with the exhaust emission control device and particulate filter regenerating method

Abstract

In an embodiment of an exhaust gas purification apparatus, when an accumulation amount of particulate matter in a DPF (33) exceeds a predetermined amount and an exhaust gas temperature of an engine is lower than a restoration operable temperature, an intake air amount reducing operation is executed by an air intake throttling device (24) provided for an air intake pipe (21) of the engine, and a heating operation is executed by an electric heater (34) provided upstream from the DPF (33), thereby increasing the exhaust gas temperature to the restoration operable temperature to start a restoration operation of the DPF (33).

Description

technical field [0001] The present invention relates to a particulate filter (hereinafter abbreviated as PM) provided in an exhaust system of an internal combustion engine typified by a diesel engine and capable of trapping particulate matter (Particulate Matter, hereinafter referred to as PM) in exhaust gas. filter), an internal combustion engine having the exhaust gas purification device, and a filter regeneration method. Background technique [0002] In recent years, in internal combustion engines installed in automobiles, etc., it is required to improve the purification of exhaust gas. In particular, in diesel engines, it is required to remove coal, etc. contained in exhaust gas in addition to reducing CO, HC, and NOx. PM. Therefore, a filter made of a porous material or the like is disposed on the exhaust passage of the engine, and the PM in the exhaust gas is captured by the filter. [0003] Since the filter is made of the porous material mentioned above, if the amou...

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Problems solved by technology

[0026] As mentioned above, in the conventional method for detecting the amount of PM accumulation, the reliability cannot be ensured sufficiently, so there is a possibility of misjudgment of the amount of PM accumulation in the filter

For example, in a situation where the PM accumulation amount is misjudged to have reached a predetermined amount (an amount that requires filter regeneration) irrespective of the fact that the actual PM accumulation amount is small, the regeneration operation is frequently performed, resulting in the need for the regeneration operation. The increase in energy (for example, in the case of filter heating by an electric heater, the power consumption increases), or the possibility of adversely affecting the life of the filter due to frequent filter heating

Conversely, when the actual PM accumulation amount has reached the above-mentioned specified amount, if it is misjudged that the PM accumulation amount has not reached the specified amount, the filter will be excessively clogged, and the exhaust pressure loss will increase, resulting in a drop in engine output and fuel consumption. Worsening attrition rate

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