Accumulating amount estimating device detecting differential pressure of filter

A method for estimating an amount of soot accumulating on a filter, which is provided to an exhaust passage of an internal combustion engine, the method comprising:

• detecting differential pressure of the filter using an accumulating amount estimating means, wherein the differential pressure of the filter is differential pressure between upstream of the filter and downstream of the filter;
• detecting an oxidizing condition of soot, which accumulates on the filter, using an oxidizing condition detecting means;
• and
• increasing temperature of the filter to be equal to or greater than oxidizing temperature of soot using a forcible oxidizing means for forcibly oxidizing soot accumulating in the vicinity of a catalyst supported by the filter, when the oxidizing condition detecting means detects a condition, in which soot accumulating in the vicinity of the catalyst on the filter is only partially oxidized;
• and
• estimating the amount of soot accumulating on the filter using the accumulating amount estimating means in accordance with the differential pressure of the filter after the forcible oxidizing means oxidizes soot accumulating in the vicinity of the catalyst on the filter, when the oxidizing condition detecting means detects the condition, in which soot accumulating in the vicinity of the catalyst on the filter is only partially oxidized,
• wherein when the oxidizing condition detecting means detects a condition, in which soot accumulating on the filter is at least substantially entirely unoxidized, the accumulating amount estimating means estimates the amount of soot accumulating on the filter using an unoxidized map in accordance with the detected differential pressure of the filter,
• when the oxidizing condition detecting means detects a condition, in which soot accumulating in the vicinity of the catalyst on the filter is at least substantially entirely oxidized, the accumulating amount estimating means estimates the amount of soot accumulating on the filter using an oxidized map in accordance with the detected differential pressure of the filter, and
• when the oxidizing condition detecting means detects a condition, in which soot accumulating in the vicinity of the catalyst on the filter is only partially oxidized, the accumulating amount estimating means estimates the amount of soot accumulating on the filter using the oxidized map in accordance with the detected differential pressure of the filter after the forcible oxidizing means oxidizes soot accumulating in the vicinity of the catalyst on the filter,
• wherein the unoxidized map represents a relationship between the differential pressure of the filter and the amount of soot accumulating on the filter when soot accumulating on the filter is at least substantially entirely unoxidized, and
• the oxidized map represents the relationship between the differential pressure of the filter and the amount of soot accumulating on the filter when soot accumulating in the vicinity of the catalyst on the filter is at least substantially entirely oxidized.

Apparatus comprising:

• a filter supporting a catalyst in an exhaust passage of an internal combustion engine;
• means for detecting a differential pressure between upstream and downstream sides of the filter and estimating an amount of soot accumulated on the filter based on the detected differential pressure;
• means for detecting an oxidizing condition of soot accumulated on the filter;
• and
• means for increasing a temperature of the filter to be equal to or greater than an oxidizing temperature of soot thereby forcibly oxidizing soot accumulated in the vicinity of catalyst supported by the filter,
• wherein when it is detected that soot accumulated in the vicinity of the catalyst is only partially oxidized, the amount of soot accumulated on the filter is estimated after soot accumulated in the vicinity of the catalyst has been forcible oxidized;
• an unoxidized map representing a relationship between the differential pressure of the filter and the amount of substantially entirely unoxidized soot accumulated on the filter;
• an oxidized map representing a relationship between the differential pressure of the filter and the amount of substantially entirely oxidized soot accumulated on the filter in the vicinity of the catalyst;
• wherein, when it is detected that soot accumulated on the filter is substantially entirely unoxidized, the amount of soot accumulated on the filter is estimated using the unoxidized map based on the detected differential pressure of the filter;
• wherein, when it is detected that soot accumulated in the vicinity of the catalyst on the filter is substantially entirely oxidized, the amount of soot accumulated on the filter is estimated using the oxidized map based on the detected differential pressure of the filter, and
• wherein, when it is detected that soot accumulated in the vicinity of the catalyst on the filter is only partially oxidized, the amount of soot accumulated on the filter is estimated using the oxidized map based on detected differential pressure of the filter the accumulated soot has been forcibly oxidized.

A method for estimating an amount of soot accumulated on a filter situated in an exhaust passage of an internal combustion engine, the method comprising:

• detecting differential upstream/downstream filter;
• detecting an oxidizing condition of soot, accumulated on the filter;
• increasing filter temperature to be equal to or greater than an oxidizing temperature of soot and forcibly oxidizing accumulated soot in the vicinity of a filter-supported catalyst when soot accumulated in the vicinity of the catalyst is only partially oxidized;
• estimating the amount of accumulated soot based on the differential filter pressure after forcibly oxidizing accumulated soot in the vicinity of the catalyst when accumulated soot is only partially oxidized;
• wherein when accumulated soot is substantially entirely unoxidized, the amount of accumulated soot is estimated using an unoxidized map and the detected differential filter pressure;
• wherein when the accumulated soot is substantially entirely oxidized, estimating the amount of accumulated soot using an oxidized map and the detected differential filter pressure;
• and
• wherein when the accumulated soot is only partially oxidized, the amount of accumulated soot is estimated using the oxidized map and the detected differential filter pressure after forcibly oxidizing accumulated soot in the vicinity of the catalyst;
• wherein the unoxidized map represents a relationship between the differential filter pressure and the amount of accumulated soot when that soot is substantially entirely unoxidized, and
• wherein the oxidized map represents a relationship between the differential filter pressure and the amount of accumulated soot when that soot is substantially entirely oxidized.