Abstract: If an exhaust throttle valve changes to ON state from OFF state under a filter regeneration control condition for regenerating a PM filter, a differential pressure sensor detects a change of a differential pressure following an operation of the exhaust throttle valve. An increase in an exhaust backpressure is calculated based upon the change in the differential pressure. If the increase in the exhaust backpressure is lower than a predetermined value, the operation of the exhaust throttle valve is determined to be malfunctioning.

Abstract: Whether discharge of high-concentration, unburned fuel is indicated or not is determined based on air-fuel ratio AF, calculated air-fuel ratio AFc and exhaust temperature thco (S110, S112, S114). If it is determined that high-concentration, unburned fuel would be discharged (“no” in any of S110, S112, S114), amount of fuel addition per one addition is decreased in PM regeneration control (S116). Therefore, in a state where high concentration HC is to be discharged to the downstream of an exhaust purifying filter, the amount of fuel addition at one time is immediately decreased, so that discharge of high-concentration HC to the outside can be prevented, and generation of white smoke can reliably be prevented.

Abstract: A regeneration controller for an exhaust purification apparatus (36, 38) of an engine (2) that appropriately burns particulate matter accumulated in the exhaust purification apparatus. The regeneration controller includes an ECU (70) that determines whether an estimated accumulation amount (PMsm) of particulate matter deviates from an actual accumulation amount. When the estimated accumulation amount is less than or equal to a maximum value (BUpm) and an exhaust pressure difference (?P/GA) is greater than a correction reference value (Dp), the ECU adds a correction value corresponding to the exhaust pressure difference to the estimated accumulation amount. This causes the estimated accumulation amount to approach the actual accumulation amount.

Abstract: An exhaust purifying apparatus for an internal combustion engine includes an exhaust purifying mechanism, a fuel adding device, an electronic control device. The exhaust purifying mechanism is located in an exhaust passage and traps particulate matter. The fuel adding device adds fuel to exhaust gas that passes through the mechanism. The electronic control device detects a pressure difference between a section upstream and a section downstream of the exhaust purifying mechanism. While the fuel adding device is adding fuel to exhaust gas, the electronic control device compares the pressure difference that is detected at a predetermined point in time with the pressure difference reference value. When the pressure difference exceeds the pressure difference reference value, the electronic control device sets the manner of adding fuel to intermittent fuel addition. As a result, the exhaust purifying apparatus decreases the amount of particulate matter that remains in the exhaust purifying mechanism.

Abstract: An exhaust purifying apparatus for an internal combustion engine having a DPNR converter (26), a fuel adding device (46), and an electronic control device (50) is provided. The DPNR converter (26) is located in an exhaust passage (14) of the internal combustion engine (10). The DPNR converter (26) traps particulate matter in exhaust gas. The fuel adding device (46) adds fuel to exhaust as that passes through the DPNR converter (26). The electronic control device (50) estimates a combustion rate of particulate matter in the DPNR converter (26) in a state where the fuel adding device (46) adds fuel to the exhaust gas. Based on the estimated combustion rate, the electronic control device (50) sets a manner of adding fuel by the fuel adding device (46). As a result, the exhaust purifying apparatus suppresses excessive temperature increase of a DPNR converter (26) to which fuel is added.

Abstract: A regeneration controller for preventing a large amount of particulate matter from being suddenly burned without increasing the frequency a heating process is performed. The regeneration controller includes an ECU(70) for heating an exhaust purification apparatus to eliminate the particulate matter accumulated in the exhaust purification apparatus when an estimated accumulation amount is greater than a reference accumulation amount. The ECU(70) obtains the estimated accumulation amount by estimating the amount of particulate matter accumulated in the exhaust purification apparatus. Furthermore, the ECU (70) changes modes for heating an exhaust purification apparatus when the regeneration controller is heated and an estimated accumulation amount is within a mode change range.

Abstract: A ceramic honeycomb structure comprising a ceramic honeycomb body comprising axial grooves on its periphery and cell walls constituting a larger number of flow paths inside the grooves, and a peripheral wall layer covering the grooves, wherein there are stress release portions at least partially in the peripheral wall layer and/or between the peripheral wall layer and the grooves. The thermal expansion coefficient of the peripheral wall layer is preferably smaller than those of the cell walls in a radial direction. The peripheral wall layer is preferably formed on the ceramic honeycomb body formed by removing a peripheral wall from a ceramic green body, before or after firing the ceramic honeycomb body.

Abstract: A regeneration controller for an exhaust purification apparatus (36, 38) of an engine (2) that appropriately burns particulate matter accumulated in the exhaust purification apparatus. The regeneration controller includes an ECU (70) that determines, whether an estimated accumulation amount (PMsm) of particulate matter deviates from an actual accumulation amount. When the estimated accumulation amount is less than or equal to a maximum value (BUpm) and an exhaust pressure difference (&Dgr;P/GA) is greater than a replacement reference value (Dp) the ECU replaces the estimated accumulation amount with a greater replacement amount (UPpm). This causes the estimated accumulation amount to approach or to be the same as the actual accumulation amount.

Abstract: In an exhaust purifying apparatus, a fuel adding valve (31) supplies unburned fuel to an exhaust passage (14) of a diesel engine (10) so that particulate matter collected in a catalytic converter (33) is burned and removed. The supply of unburned fuel from the fuel adding valve (31) is executed even after an electronic control unit (41) determines that particulate matter in the catalytic converter (33) has been burned and removed. This reduces the amount of particulate matter remaining unburned in the catalytic converter (33).

Abstract: An exhaust purifying apparatus for an internal combustion engine includes execution means, wherein, when an accumulation amount of particulate matter about a catalyst becomes less than a first determination value after a PM elimination control is started, the execution means executes burn-up control. Stopping means stops the PM elimination control based on an end of the burn-up control. Forcibly ending means forcibly ends the burn-up control when time elapsed since the accumulation amount of particulate matter about the catalyst has dropped to a second determination value reaches a predetermined time. Therefore, the exhaust purifying apparatus is capable of completely burning particulate matter in a PM filter, and suppresses degradation of fuel economy.

Abstract: Whether discharge of high-concentration, unburned fuel is indicated or not is determined based on air-fuel ratio AF, calculated air-fuel ratio AFc and exhaust temperature thco (S110, S112, S114). If it is determined that high-concentration, unburned fuel would be discharged (“no” in any of S110, S112, S114), amount of fuel addition per one addition is decreased in PM regeneration control (S116). Therefore, in a state where high concentration HC is to be discharged to the downstream of an exhaust purifying filter, the amount of fuel addition at one time is immediately decreased, so that discharge of high-concentration HC to the outside can be prevented, and generation of white smoke can reliably be prevented.

Abstract: A regeneration controller that prevents overheating when performing burn-up heating for completely burning particulate matter by intermittent fuel addition to an exhaust system or intermittent increase of fuel addition to the exhaust system. The regeneration controller includes first and second exhaust temperature sensors (44, 46), each detecting the exhaust temperature at a location downstream from the exhaust purification apparatus. An ECU (70) determines the timing for stopping fuel addition to the exhaust system or increase of fuel addition to the exhaust system based on the elapsed time of fuel addition to the exhaust system or increase of fuel addition to the exhaust system.

Abstract: In an exhaust purifying apparatus, a fuel adding valve (31) supplies unburned fuel to an exhaust passage (14) of a diesel engine (10) so that particulate matter collected in a catalytic converter (33) is burned and removed. The supply of unburned fuel from the fuel adding valve (31) is executed even after an electronic control unit (41) determines that particulate matter in the catalytic converter (33) has been burned and removed. This reduces the amount of particulate matter remaining unburned in the catalytic converter (33).

Abstract: The ceramic honeycomb filter having a plurality of honeycomb structures each having an outer wall and a large number of flow paths partitioned by cell walls inside the outer wall, which are bonded to each other in the direction of the flow paths, desired flow paths on exhaust gas inlet and outlet sides being sealed, wherein at least one plug on an exhaust inlet side is disposed at a position inside the filter separate from an inlet end surface of the filter; and wherein inlet-side plugs are formed at desired positions of end portions of at least one honeycomb structure.

Abstract: An exhaust purifying apparatus estimates an accumulation amount of particulate matter trapped about a catalyst in an exhaust system. When the estimated accumulation amount is equal to or more than a permissible value, the apparatus executes PM elimination control for supplying unburned fuel component to the catalyst. The apparatus sets the estimated accumulation amount to zero at the completion of the PM elimination control. When execution of the PM elimination control becomes possible after suspension of the control, the apparatus resumes the PM elimination control even if the accumulation amount is less than the permissible value. Therefore, The estimated accumulation amount is prevented from being significantly deviated from the actual accumulation amount due to suspension.

Abstract: A ceramic honeycomb structure comprising a ceramic honeycomb body comprising axial grooves on its periphery and cell walls constituting a larger number of flow paths inside the grooves, and a peripheral wall layer covering the grooves, wherein there are stress release portions at least partially in the peripheral wall layer and/or between the peripheral wall layer and the grooves. The thermal expansion coefficient of the peripheral wall layer is preferably smaller than those of the cell walls in a radial direction. The peripheral wall layer is preferably formed on the ceramic honeycomb body formed by removing a peripheral wall from a ceramic green body, before or after firing the ceramic honeycomb body.

Abstract: A ceramic honeycomb filter comprising a ceramic honeycomb structure having porous partition walls defining a plurality of flow paths for flowing an exhaust gas through the porous partition walls to remove particulates from the exhaust gas, wherein one end of each flow path is provided with a sealer, such that sealers of the flow paths in an inlet and an outlet of the ceramic honeycomb structure in a desired pattern; wherein the partition walls have thickness of 0.1-0.5 mm and a porosity of 50-80%; wherein the porosity of the sealers is larger than that of partition walls; and wherein the depth of the sealers is 3-15 mm.

Abstract: A ceramic honeycomb filter comprising a ceramic honeycomb structure having porous partition walls defining a plurality of flow paths for flowing an exhaust gas through the porous partition walls to remove particulates from the exhaust gas, the predetermined flow paths among the flow paths being sealed at their ends, a catalyst being carried by the porous partition walls, the porous partition walls having a porosity of 60-75% and an average pore diameter of 15-25 &mgr;m when measured according to a mercury penetration method, and the maximum of a slope Sn of a cumulative pore volume curve of the porous partition walls relative to a pore diameter obtained at an n-th measurement point being 0.

Abstract: The ceramic honeycomb filter having a plurality of honeycomb structures each having an outer wall and a large number of flow paths partitioned by cell walls inside the outer wall, which are bonded to each other in the direction of the flow paths, desired flow paths on exhaust gas inlet and outlet sides being sealed, wherein at least one plug on an exhaust inlet side is disposed at a position inside the filter separate from an inlet end surface of the filter; and wherein inlet-side plugs are formed at desired positions of end portions of at least one honeycomb structure.

Abstract: A ceramic honeycomb filter comprising a ceramic honeycomb structure having porous partition walls defining a plurality of flow paths for flowing an exhaust gas through the porous partition walls to remove particulates from the exhaust gas, wherein one end of each flow path is provided with a sealer, such that sealers of the flow paths in an inlet and an outlet of the ceramic honeycomb structure in a desired pattern; wherein the partition walls have thickness of 0.1-0.5 mm and a porosity of 50-80%; wherein the porosity of the sealers is larger than that of partition walls; and wherein the depth of the sealers is 3-15 mm.