Exhaust purification apparatus for internal combustion engine

Abstract

The present invention pertains to an exhaust purification device for an internal combustion engine, in which hydrocarbons adsorbed to a catalyst are burned with appropriate timing, without increasing the number of components or complicating the structure. An exhaust purification device (14) of an internal combustion engine (10) in which a catalyst (15) capable of adsorbing and oxidizing hydrocarbons is provided in an exhaust pipe, wherein the exhaust purification device (14) is provided with: a temperature detection means (13) for detecting the temperature of the catalyst (15); an estimation means (40) for accumulating times during which the temperature of the catalyst (15) as detected by the temperature detection means (13) is equal to or less than a prescribed temperature, and estimating the amount of hydrocarbons adsorbed to the catalyst (15) from the accumulated times; and a control means (40) for controlling the fuel injection of the internal combustion engine (10) in a first injection mode for raising the temperature of the catalyst (15) to the temperature at which the hydrocarbons adsorbed to the catalyst (15) oxidize, when the amount of hydrocarbons estimated by the estimation means (40) exceeds a prescribed upper limit value.

Description

technical field [0001] The present invention relates to an exhaust purification device for an internal combustion engine. Background technique [0002] In an internal combustion engine such as a diesel engine, nitrogen oxides, particulate matter (PM) and the like are generated by combustion. In a vehicle powered by such an internal combustion engine, purification devices such as an oxidation catalyst (DOC) and a diesel particulate filter (DPF) are provided in the exhaust path in order to suppress these substances from being emitted together with the exhaust gas. [0003] The DPF is a device for trapping PM contained in exhaust gas through a filter. The performance of DPF gradually decreases due to PM accumulation and filter mesh clogging during use. Therefore, high-temperature exhaust gas is fed into the DPF to burn accumulated PM. A method of generating high-temperature exhaust gas is generally a method in which unburned hydrocarbons (HC) are contained in the exhaust gas...

AI Technical Summary

Problems solved by technology

[0004] However, if the DOC exceeds the usable temperature, it will easily deteriorate and its performance will decrease

Therefore, if more than necessary HC is adsorbed and accumulated in DOC, during combustion, the usable temperature may be exceeded and DOC may be deteriorated.

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