Abstract: A diagnostic device for an exhaust gas purification system that has a diesel oxidation catalyst (DOC), a diesel particulate filter, and an exhaust pipe injection device. The device includes a sensor for detecting a temperature of the DOC, a first calculation unit for converting an integration time of the detected temperature between regeneration intervals into a thermal history time with respect to a predetermined set temperature, and calculating a degree of degradation of the DOC based on this thermal history time, a second calculation unit for calculating a quantity of heat generated in the DOC based on the detected temperature during a forced regeneration execution period, and calculating another degree of degradation of the DOC based on the quantity of heat generated; and a diagnosis unit for diagnosing a degradation state of the DOC based on the degrees of degradation entered from the first and second calculation units.

Abstract: A diagnostic device for an exhaust gas purification system that has a diesel oxidation catalyst (DOC), a diesel particulate filter, and an exhaust pipe injection device. The device includes a sensor for detecting a temperature of the DOC, a first calculation unit for converting an integration time of the detected temperature between regeneration intervals into a thermal history time with respect to a predetermined set temperature, and calculating a degree of degradation of the DOC based on this thermal history time, a second calculation unit for calculating a quantity of heat generated in the DOC based on the detected temperature during a forced regeneration execution period, and calculating another degree of degradation of the DOC based on the quantity of heat generated; and a diagnosis unit for diagnosing a degradation state of the DOC based on the degrees of degradation entered from the first and second calculation units.

Abstract: In an exhaust gas purification system provided with an exhaust gas purification device in an exhaust passage of an internal combustion engine, and at the same time, provided with a reductant supply means for supplying a reductant to the upstream side of this exhaust gas purification device, two or more of the oxygen concentration, the CO concentration, and the HC concentration of the exhaust gas detected by an exhaust gas component concentration detecting means are used as control parameters during the reductant supply control when the reductant is supplied into the exhaust gas flowing into the exhaust gas purification device. With this, the supply period and supply amount of the reductant can be optimized, and a decrease of fuel efficiency deterioration and suppression of deterioration of the quality of the components of the exhaust gas flowing into the atmosphere are attempted.

Abstract: An exhaust gas purification catalyst (1) for purifying exhaust gas has a structure in which a mixture of an oxide (31) having oxygen storage capacity and an oxide semiconductor (33) is supported. The oxide (31) having oxygen storage capacity is formed of an oxide containing cerium (Ce), and the oxide semiconductor (33) is formed of any one of or a combination of titanium dioxide (TiO2), zinc oxide (ZnO), and yttrium oxide (Y2O3). In addition, a noble metal (32) is supported on the oxide (31) having oxygen storage capacity, or a noble metal (34) is supported on the oxide semiconductor (33). Accordingly, provided are an exhaust gas purification catalyst, an exhaust gas purification system, and an exhaust gas purification method with a high activity even in low-temperature exhaust gas at a time when an internal-combustion engine starts up or is under a low load condition.

Abstract: In an exhaust gas purification system provided with an exhaust gas purification device in an exhaust passage of an internal combustion engine, and at the same time, provided with a reductant supply means for supplying a reductant to the upstream side of this exhaust gas purification device, two or more of the oxygen concentration, the CO concentration, and the HC concentration of the exhaust gas detected by an exhaust gas component concentration detecting means are used as control parameters during the reductant supply control when the reductant is supplied into the exhaust gas flowing into the exhaust gas purification device. With this, the supply period and supply amount of the reductant can be optimized, and a decrease of fuel efficiency deterioration and suppression of deterioration of the quality of the components of the exhaust gas flowing into the atmosphere are attempted.

Abstract: The fiber-strengthened silicon nitride sintered substance (10) comprises silicon nitride particles (2), an oxide or nitride grain boundary phase (4) containing silicon (3), a silicon nitride layer (5) and strengthened fibers (6). Contained in the oxide or nitride grain boundary phase (4) are a crystal phase (12) containing MnSiN2, at least one element selected from the group consisting of aluminum (Al), yttrium (Y) and silicon (Si), and an amorphous phase (14) containing manganese (Mn), oxygen (O) and nitrogen (N).

Abstract: An exhaust gas purifying apparatus provides a reflux pipe for connecting an intake pipe to an exhaust pipe and an EGR valve disposed in the reflux pipe for adjusting a flow rate of the exhaust gas flowing through the reflux pipe. A nitrogen oxide purifying catalyst section is formed by a brown miralite type composite oxide. A pair of electrodes are provided on the vicinity of the opposite ends of the purifying catalyst section. A conductivity measuring section measures conductivity of a nitrogen oxide catalyst of the nitrogen oxide purifying catalyst section through the electrodes. A control section controls an opening degree of the EGR valve on the basis of engine rpm, engine load and the conductivity measured in the conductivity measuring section.

Abstract: An exhaust gas purifying catalyst for use in an oxygen surplus atmosphere, includes a brown millerite composite oxide for directly decomposing and absorbing nitrogen oxide (NOx), and a noble metal-series reducing catalyst disposed on the surface of said brown millerite composite oxide. The brown millerite composite oxide is represented by one of the following formulae: A3-aBaC4-bDbO9, A2-aBaC2-bDbO5, and A1-aBaC2-bDbO4 where A and B are elements selected from the group consisting of Ba, Ca, Sr, Mg and Ce, C and D are elements selected from the group consisting of Y, Dy, Zn, Ti, Mn, Fe, Co, Ni, Cu, Sn, Zr and Nd, a is within the range 0≦a<1, and b is within the range 0≦b<2.

Abstract: The heat resistant stainless steel wire/strip comprises a stainless steel thin wire/strip containing, in addition to chrome, at least one of nickel, aluminum and yttrium. The stainless steel thin wire/strip is covered with a covering layer formed of nickel group alloy particles containing aluminum covered with ceramic particles or chrome alloy particles containing aluminum covered with ceramic particles. The stainless steel thin wire/strip with the covering layer is applied with heat treatment in vacuum at a temperature of 1100 to 1300.degree. C., the alloy particles are deposited on the stainless steel thin wire/strip, and the alloy particles and the ceramic particles of the covering layer are bonded to each other. The ceramic particles of the covering layer is 1 micron or less of an average particle diameter and contain at least one of aluminum, silicone, magnesium, zirconium, barium and titanium.