Abstract: An exhaust emission purifying apparatus has a NOx reduction catalytic converter in an exhaust passage of an engine, for purifying nitrogen oxides in the exhaust gas by reduction with urea aqueous solution; an injection nozzle injecting the urea solution toward an exhaust upstream side of the converter in the exhaust passage; and fins disposed on an exhaust upstream side of an injection position of the urea solution in the injection nozzle, for generating a spiral swirling flow of the gas swirling about a center corresponding to the central axis of an exhaust pipe. The swirling flow generated in the exhaust gas prior to the injection-supply of the urea aqueous solution promotes mixing of the solution with the gas to thereby promote the hydrolysis of the urea solution. And the exhaust gas and ammonia generated from the urea solution are uniformly mixed together.

Abstract: An exhaust emission purifying apparatus of the present invention has a casing that includes therein a plurality of layered passages which is formed by partitioning an inside of the casing to thereby allow an exhaust passage from an exhaust emission inlet to an exhaust emission outlet to be folded in its direction once or more, a reduction catalyst that reductively purifies NOx by using a reducing agent, a nozzle that injects the reducing agent or a precursor thereof to an exhaust upstream side of the reduction catalyst, and a filter (DPF) that collects PM suspended in an exhaust emission. The reduction catalyst and the filter are disposed in the different layered passages. Consequently, a more compact exhaust emission purifying apparatus having both NOx removal function and PM collection function can be provided.

Abstract: When an abnormality occurred in a SCR device is detected, the output of an engine is restricted. To this end, in one embodiment, at the time of an abnormality occurrence, a map adopted for calculating a fuel injection quantity is switched from that for a normal time (S407). Further, as the abnormality to be detected, the clogging of an injection nozzle, the dilution of urea water stored in a tank, or the like is adopted.

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even if precipitation of the dissolved matter occurs, the

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even If precipitation of the dissolved matter occurs, the

Abstract: Provided in a catalyst system are: a first reaction part fitted with a first catalyst containing, as active constituents, at least, a complex oxide consisting of two or more oxides selected from among silica, alumina, titania, zirconia, and tungsten oxide, and a rare earth metal or transition metal (except Cu, Co, Ni, Mn, Cr, and V); and a second reaction part fitted with a second catalyst containing, as active constituents, at least, a noble metal and a silica-alumina type complex oxide.

Abstract: For preventing clogging in an injection nozzle for supplying a reducing agent to exhaust gas flow on an upstream side of a reducing catalyst and for improving the efficiency of NOx purification processing, the injection nozzle 14 has a tip end portion 18 provided with a ring shaped protruding ridge 19 disposed on an outer peripheral surface of an exhaust gas downstream side end portion of the tip end portion 18 that is arranged substantially in parallel with an exhaust gas flow direction A inside an exhaust pipe 13, the ring shaped protruding ridge 19 being provided with injection hole or holes 20 drilled outward from the central axis of the injection nozzle 14, so that the reducing agent is ejected on the exhaust gas upstream side of the reduction catalyst, from the injection holes 20.

Abstract: A liquid reducing agent of a necessary amount according to an engine operating condition is injection-supplied from a nozzle having an injection hole opening to inside an exhaust gas passage, positioned on an exhaust gas upstream side of a nitrogen oxide reduction catalyst. On the other hand, when an injection flow rate of the liquid reducing agent becomes zero, compressed air stored in a purge air tank is supplied into the nozzle for a predetermined time. Thus, the liquid reducing agent remaining in the nozzle is forcibly discharged by the compressed air, and hence even if the nozzle is at a high temperature due to the exhaust heat, a situation where reducing agent constituents are deposited does not occur, and clogging of the inside of the nozzle can be prevented.

Abstract: In order to suppress deposition of constituent of a reducing agent (dissolved matter) in an exhaust passage of an engine enhancing an elimination rate of NOx even when temperature of an exhaust emission from the engine is low, an exhaust emission purifying apparatus is provided with an electro-generative-heat carrier provided on an upstream side of an injection nozzle that supplies the reducing agent into the exhaust emission on upstream side of a reduction catalyst in an exhaust pipe, the exhaust emission being heated to a temperature equal to or higher than a melting point of the dissolved matter whereby deposition of the dissolved matter on an inner wall surface of the exhaust pipe is suppressed to effectively use the supplied reducing agent for catalytic reduction reaction, even when the exhaust emission temperature is lower than the melting point of the dissolved matter of the reducing agent.

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even if precipitation of the dissolved matter occurs, the

Abstract: An exhaust emission purifying apparatus for an engine having: a reduction catalytic converter disposed in an exhaust system of the engine, for reductively purifying nitrogen oxides in the exhaust emission with a reducing agent; an injection nozzle for injection-supplying the reducing agent to an exhaust upstream side of the reduction catalytic converter in an exhaust pipe of the exhaust system; and a reducing agent supply device supplying the reducing agent to the injection nozzle, in which a recess portion is formed on an inner wall on a lower portion of the exhaust pipe, by concaving a site to which at least the reducing agent injection-supplied from the injection nozzle is attached, and also, a bottom wall of the recess portion is made detachable.

Abstract: In order to suppress deposition of constituent of a reducing agent (dissolved matter) in an exhaust passage of an engine enhancing an elimination rate of NOx even when temperature of an exhaust emission from the engine is low, an exhaust emission purifying apparatus is provided with an electro-generative-heat carrier provided on an upstream side of an injection nozzle that supplies the reducing agent into the exhaust emission on upstream side of a reduction catalyst in an exhaust pipe, the exhaust emission being heated to a temperature equal to or higher than a melting point of the dissolved matter whereby deposition of the dissolved matter on an inner wall surface of the exhaust pipe is suppressed to effectively use the supplied reducing agent for catalytic reduction reaction, even when the exhaust emission temperature is lower than the melting point of the dissolved matter of the reducing agent.

Abstract: An exhaust emission purifying apparatus of the present invention has a casing that includes therein a plurality of layered passages which is formed by partitioning an inside of the casing to thereby allow an exhaust passage from an exhaust emission inlet to an exhaust emission outlet to be folded in its direction once or more, a reduction catalyst that reductively purifies NOx by using a reducing agent, a nozzle that injects the reducing agent or a precursor thereof to an exhaust upstream side of the reduction catalyst, and a filter (DPF) that collects PM suspended in an exhaust emission. The reduction catalyst and the filter are disposed in the different layered passages. Consequently, a more compact exhaust emission purifying apparatus having both NOx removal function and PM collection function can be provided.

Abstract: Provided in a catalyst system are: a first reaction part fitted with a first catalyst containing, as active constituents, at least, a complex oxide consisting of two or more oxides selected from among silica, alumina, titania, zirconia, and tungsten oxide, and a rare earth metal or transition metal (except Cu, Co, Ni, Mn, Cr, and V); and a second reaction part fitted with a second catalyst containing, as active constituents, at least, a noble metal and a silica-alumina type complex oxide.

Abstract: In relation to an exhaust gas purification system that mixes a liquid reducing agent with air and injection-supplies this mixture into an exhaust gas flowing on an upstream side of a reduction catalyst (20) to thereby effect reduction purification of NOx in exhaust gas, a technical attention is directed to the relation of respective elements of; the travel distance, the fuel consumption, the air consumption, or the running time and the like, and the liquid reducing agent consumption, to constitute a configuration such that a continual monitor as to whether the injection condition of liquid reducing agent is normal or abnormal is executed by judging whether or not the amount of liquid reducing agent consumed for a predetermined travel distance, a predetermined fuel consumption, a predetermined air consumption, or a predetermined running time, is within a predetermined range.

Abstract: A liquid reducing agent of a necessary amount according to an engine operating condition is injection-supplied from a nozzle having an injection hole opening to inside an exhaust gas passage, positioned on an exhaust gas upstream side of a nitrogen oxide reduction catalyst. On the other hand, when an injection flow rate of the liquid reducing agent becomes zero, compressed air stored in a purge air tank is supplied into the nozzle for a predetermined time. Thus, the liquid reducing agent remaining in the nozzle is forcibly discharged by the compressed air, and hence even if the nozzle is at a high temperature due to the exhaust heat, a situation where reducing agent constituents are deposited does not occur, and clogging of the inside of the nozzle can be prevented.

Abstract: An exhaust pipe for an exhaust gas is provided, at its position on upstream side of nitrogen oxides (NOx) catalytic converter, with an internal tubular member disposed to have open opposite ends in a direction along exhaust gas flow while leaving a clearance between internal tubular member and exhaust pipe inner wall. A urea aqueous solution from the storage tank is additively injected by an injection nozzle in a direction of exhaust gas flow within internal tubular member capable of being heated by exhaust gas in exhaust pipe, to thereby shortly bring temperature of internal tubular member to become substantially equal to an exhaust gas temperature. Thus, temperature of urea aqueous solution additively injected into internal tubular member does not decrease when the solution adheres to an inner wall of that tubular member forming liquid droplets, thereby enhancing hydrolysis an inner wall of urea aqueous solution.

Abstract: For preventing clogging in an injection nozzle for supplying a reducing agent to exhaust gas flow on an upstream side of a reducing catalyst and for improving the efficiency of NOx purification processing, the injection nozzle 14 has a tip end portion 18 provided with a ring shaped protruding ridge 19 disposed on an outer peripheral surface of an exhaust gas downstream side end portion of the tip end portion 18 that is arranged substantially in parallel with an exhaust gas flow direction A inside an exhaust pipe 13, the ring shaped protruding ridge 19 being provided with injection hole or holes 20 drilled outward from the central axis of the injection nozzle 14, so that the reducing agent is ejected on the exhaust gas upstream side of the reduction catalyst, from the injection holes 20.

Abstract: An exhaust emission purifying apparatus has a NOx reduction catalytic converter in an exhaust passage of an engine, for purifying nitrogen oxides in the exhaust gas by reduction with urea aqueous solution; an injection nozzle injecting the urea solution toward an exhaust upstream side of the converter in the exhaust passage; and fins disposed on an exhaust upstream side of an injection position of the urea solution in the injection nozzle, for generating a spiral swirling flow of the gas swirling about a center corresponding to the central axis of an exhaust pipe. The swirling flow generated in the exhaust gas prior to the injection-supply of the urea aqueous solution promotes mixing of the solution with the gas to thereby promote the hydrolysis of the urea solution. And the exhaust gas and ammonia generated from the urea solution are uniformly mixed together.

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even If precipitation of the dissolved matter occurs, the