Claims
- 1. An exhaust gas purification apparatus, for an engine having a combustion chamber, comprising an exhaust passage, a particulate filter arranged in the exhaust passage for removing particulates in exhaust gas exhausted from the combustion chamber by oxidation, a device for controlling a characteristic of the exhaust gas flowing into the particulate filter, and means for judging if the particulate filter will be deteriorated by heat derived from the oxidation of the particulates, wherein, when the judging means judges that the particulate filter will be deteriorated by heat, the controlling device changes the characteristic of the exhaust gas flowing into the particulate filter to prevent the particulate filter from being deteriorated by heat; and
wherein the controlling device is adapted to control the amount of the exhaust gas flowing into the particulate filter and wherein, when the judging means judges that the particular filter will be deteriorated by heat, the controlling device performs one of a first control operation to make the amount of the exhaust gas flowing into the particulate filter smaller than a first threshold and a second control operation to make the amount of the exhaust gas flowing into the particulate filter larger than a second threshold which is larger than the first threshold.
- 2. An exhaust gas purification apparatus, as set forth in claim 1, wherein the apparatus further comprises a bypass mechanism for making at least a part of the exhaust gas bypass the particulate filter, and wherein the controlling device makes the amount of the exhaust gas flowing into the particulate filter smaller than the first threshold by the bypass mechanism making at least a part of the exhaust gas bypass the particulate filter.
- 3. An exhaust gas purification apparatus, as set forth in claim 1, wherein the controlling device makes the amount of the exhaust gas flowing into the particulate filter smaller than the first threshold by reducing an amount of air taken into the combustion chamber, and makes the amount of the exhaust gas flowing into the particulate filter larger than the second threshold by increasing the amount of air taken into the combustion chamber.
- 4. An exhaust gas purification apparatus, as set forth in claim 3, wherein the controlling device reduces the amount of air taken into the combustion chamber by reducing the engine speed, and increases the amount of air taken into the combustion chamber by increasing the engine speed.
- 5. An exhaust gas purification apparatus, as set forth in claim 2, wherein a precious metal catalyst is carried on the particulate filter.
- 6. An exhaust gas purification apparatus, as set forth in claim 2, wherein an active oxygen release agent which absorbs and holds oxygen when excess oxygen is present in the surroundings and releases the held oxygen in the form of active oxygen when the concentration of oxygen in the surroundings falls is carried on the particulate filter and wherein active oxygen is released from the active oxygen release agent and the particulates adhering on the particulate filter are oxidized by the released active oxygen when the particulates adhere on the particulate filter.
- 7. An exhaust gas purification apparatus, as set forth in claim 6, wherein the active oxygen release agent is comprised of at least one of an alkali metal, an alkali earth metal, a rare earth, a transition metal, and a carbon family element.
- 8. An exhaust gas purification apparatus, as set forth in claim 7, wherein the alkali metal and alkali earth metal are comprised of metals higher in tendency toward ionization than calcium.
- 9. An exhaust gas purification apparatus, as set forth in claim 2, wherein a NOx absorbent for absorbing NOx in the exhaust gas when excess oxygen is present in the surroundings and releases the absorbed NOx when the concentration of oxygen in the surroundings falls is carried on the particulate filter and wherein the characteristic of the exhaust gas flowing into the particulate filter is returned to an original characteristic when a predetermined period has elapsed from when the controlling device changes the characteristic of the exhaust gas, and sulfur adhering on the particulate filter is disassociated from the particulate filter by making the air-fuel ratio of a part or the whole of the exhaust gas rich.
- 10. An exhaust gas purification apparatus, for an engine having a combustion chamber, comprising an exhaust passage, a particulate filter arranged in the exhaust passage for removing particulates in exhaust gas exhausted from the combustion chamber by oxidation, a device for controlling a characteristic of the exhaust gas flowing into the particulate filter, and means for judging if the particulate filter will be deteriorated by heat derived from the oxidation of the particulates, wherein, when the judging means judges that the particulate filter will be deteriorated by heat, the controlling device changes the characteristic of the exhaust gas flowing into the particulate filter to prevent the particulate filter from being deteriorated by heat; and
wherein the judging means judges that the particulate filter will be deteriorated by heat when the temperature of the particulate filter is higher than a predetermined temperature.
- 11. An exhaust gas purification apparatus, as set forth in claim 10, wherein the predetermined temperature is a temperature at which the particulate is ignited.
Priority Claims (4)
Number |
Date |
Country |
Kind |
2000-227569 |
Jul 2000 |
JP |
|
2000-227558 |
Jul 2000 |
JP |
|
2001-133597 |
Apr 2001 |
JP |
|
2001-140559 |
May 2001 |
JP |
|
Parent Case Info
[0001] This is a Continuation of application No. 10/088,476 filed Mar. 20, 2002, which is a National Stage of PCT/JP01/06350 filed Jul. 23, 2001. The entire disclosures of the prior applications are hereby incorporated by reference herein in their entireties.
Continuations (1)
|
Number |
Date |
Country |
Parent |
10088476 |
Mar 2002 |
US |
Child |
10866710 |
Jun 2004 |
US |