Exhaust Gas Control Apparatus for Internal Combustion Engine

Abstract

When the temperature of exhaust gas control means (3), which is provided in an exhaust passage (2) of an internal combustion engine (1) and which has oxidation function, is increased to a target temperature in order to recover an exhaust gas control ability of the exhaust gas control means (3), the method of increasing the temperature of the exhaust gas control means (3) is switched between a method in which the temperature of the exhaust gas control means (3) is increased by controlling an amount of fuel supplied to the exhaust gas control means (3) and a method in which the fuel supply to the exhaust gas control means (3) is prohibited and the temperature of the exhaust gas control means (3) is increased by controlling an amount of air taken in the internal combustion engine (1), based on an operation state of the internal combustion engine (1).

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention relates to an exhaust gas control apparatus for an internal combustion engine, which includes exhaust gas control means that is provided in an exhaust passage of an internal combustion engine and that has oxidation function. [0003] 2. Description of the Related Art [0004] In an exhaust gas control apparatus for an internal combustion engine, a particulate filter (hereinafter, referred to as a “filter”) which traps particulate matter (hereinafter, referred to as “PM”) in exhaust gas, a NOx storage reduction catalyst, or the like may be provided in an exhaust passage of an internal combustion engine. In the case where the filter is provided in the exhaust passage, the temperature of the filter needs to be increased when PM accumulated in the filter is removed. In the case where the NOx storage reduction catalyst is provided in the exhaust passage, the temperature of the NOx storage reduction catalyst nee...

AI Technical Summary

Benefits of technology

The invention relates to a technology for increasing the temperature of exhaust gas control means in an internal combustion engine to recover their function more appropriately. The technology involves switching between a method of controlling the temperature by controlling the amount of fuel supplied to the control means and a method of controlling the temperature by controlling the amount of air taken in the engine. This allows for a broader range of temperatures at which the control means can operate, and more appropriately recover their function based on the engine load. The technology also includes a fuel supply means for supplying fuel to the control means and an intake air amount control means for controlling the amount of air taken in the engine. This allows for a more accurate control of the exhaust gas control means, and prevents excessive temperature increases that can occur when fuel is burned in the cylinder or exhaust passage.

Problems solved by technology

However, it is sometimes difficult, due to the operation state of the internal combustion engine, to supply the exhaust gas control means with a sufficient amount of fuel that is required for increasing the temperature of the exhaust gas control means to a target temperature at which the exhaust gas control ability of the exhaust gas control means can be recovered.

Accordingly, there is a possibility that the fuel injected by the sub-fuel injection or the fuel supplied to the exhaust passage is burned in the cylinder or the exhaust passage, and therefore, a sufficient amount of fuel is not supplied to the exhaust gas control means.

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