Exhaust purification system of internal combustion engine

Abstract

A particulate filter for trapping particulate filter which is contained in exhaust gas is arranged in an engine exhaust passage. The particulate filter is provided with exhaust gas inflow passages and exhaust gas outflow passages which are alternately arranged via porous partition walls. Movement promoting control is performed to promote movement of the ash which deposits on the inner circumferences of the exhaust gas inflow passages to the rear parts of the exhaust gas inflow passages. The pressure loss of the particulate filter is detected. When the detected pressure loss is larger than a predetermined upper limit value, PM removal control is performed to remove the particulate matter from the particulate filter.

1 . An exhaust purification system comprising:
 an internal combustion engine;   an engine exhaust passage;   a particulate filter configured to trap particulate matter contained in exhaust gas, the particulate filter being disposed inside the engine exhaust passage, the particulate filter including exhaust gas inflow passages and exhaust gas outflow passages, and the exhaust pas inflow passages and the exhaust gas outflow passages being alternately arranged through porous partition walls;   a detecting means for detecting pressure loss of the particulate filter;   a movement promoting means for promoting movement of ash deposited on inner circumferences of the exhaust gas inflow passages to rear parts of the exhaust gas inflow passages; and   a PM removing means for performing PM removal control for removing the particulate matter from the particulate filter when the detected pressure loss is greater than a predetermined upper limit value,   wherein the movement promoting means determines whether an mount of ash deposited on the inner circumferences of the exhaust gas inflow passages is greater than a predetermined upper limit amount, and   the movement promoting means performs movement promoting control when the movement promoting means determines that the amount of ash is greater than the predetermined upper limit amount.   
     
     
         2 . (canceled) 
     
     
         3 . The exhaust purification system according to  claim 1 , wherein
 the movement promoting means supplies a liquid to the particulate filter, to perform the movement promoting control.   
     
     
         4 . The exhaust purification system according to  claim 3 , wherein
 the liquid is comprised of at least one of water, an aqueous solution, or a liquid fuel.   
     
     
         5 . The exhaust purification system according to  claim 3 , further comprising:
 a condensed water storage part disposed in at least one of an engine intake passage, the engine exhaust passage upstream of the particulate filter, or an exhaust gas recirculation passage that connects the engine intake passage and the engine exhaust passage with each other, the condensed water storage part being configured to store condensed water generated at the internal combustion engine,   wherein the movement promoting means supplies the condensed water stored in the condensed water storage part to the particulate filter, to perform the movement promoting control.   
     
     
         6 . The exhaust purification system according to  claim 3 , further comprising:
 a NOx reducing catalyst arranged inside the particulate filter or in the engine exhaust passage downstream of the particulate filter;   a reducing agent addition valve configured to secondarily add a liquid reducing agent into the engine exhaust passage upstream of the particulate filter; and   a NOx reducing means for adding a liquid reducing agent from the reducing agent addition valve with a NOx reduction addition pressure and a NOx reduction addition time for reducing the NOx,   wherein the movement promoting means adds the liquid reducing agent from the reducing agent addition valve with an addition pressure that is lower than the NOx reduction addition pressure or with an addition time that is longer than the NOx reduction addition time, to perform the movement promoting control.   
     
     
         7 . The exhaust purification system according to  claim 1 , wherein
 the movement promoting means makes pressure inside of the particulate filter pulsate, to perform the movement promoting control.   
     
     
         8 . The exhaust purification system according to  claim 1 , wherein
 the movement promoting means makes the particulate filter vibrate, to perform the movement promoting control.   
     
     
         9 . The exhaust purification system according to  claim 1 , wherein
 the movement promoting means makes temperature of the particulate filter rise to a temperature higher than that at the time of the PM removal control, to perform the movement promoting control.   
     
     
         10 . The exhaust purification system according to  claim 1 , wherein
 the movement promoting means feeds a liquid to the particulate filter, and the movement promoting means makes the liquid solidify, to perform the movement promoting control.   
     
     
         11 . An exhaust purification system comprising:
 an internal combustion engine;   an engine exhaust passage;   a particulate filter configured to trap particulate matter contained in exhaust gas, the particulate filter being disposed inside the engine exhaust passage, the particulate filter including exhaust gas inflow passages and exhaust gas outflow passages, and the exhaust gas inflow passages and the exhaust gas outflow passages being alternately arranged through porous partition walls;   a pressure loss sensor configured to detect pressure loss of the particulate filter;   an electronic control unit configured to:   (i) promote movement of ash deposited on inner circumferences of the exhaust gas inflow passages to rear parts of the exhaust gas inflow passages,   (ii) perform PM removal control for removing the particulate matter from the particulate filter when the detected pressure loss is greater than a predetermined upper limit value,   (iii) determine whether an amount of ash deposited on the inner circumferences of the exhaust gas inflow passages is greater than a predetermined upper limit mount, and   (iv) perform movement promoting control when the electronic control unit determines that the amount of ash is greater than the predetermined upper limit amount.   
     
     
         12 . An exhaust purification method for a vehicle including:
 an internal combustion engine;   an engine exhaust passage;   a particulate filter configured to trap particulate matter contained in exhaust gas, the particulate filter being disposed inside the engine exhaust passage, the particulate filter including exhaust gas inflow passages and exhaust gas outflow passages, and the exhaust gas inflow passages and the exhaust gas outflow passages being alternately arranged through porous partition walls; and   a pressure loss sensor configured to detect pressure loss of the particulate filter;   an electronic control unit,   the exhaust purification method comprising:   (i) promoting, by the electronic control unit, movement of ash deposited on inner circumferences of the exhaust gas inflow passages to rear parts of the exhaust gas inflow passages;   (ii) performing, by the electronic control unit, PM removal control for removing the particulate matter from the particulate filter when the detected pressure loss is greater than a predetermined upper limit value;   (iii) determining, by the electronic control unit, whether an amount of ash deposited on the inner circumferences of the exhaust gas inflow passages is greater than a predetermined upper limit amount; and   (iv) performing, by the electronic control unit, movement promoting control when the electronic control unit determines that the amount of ash is greater than the predetermined upper limit amount.