摘要:
Even in a vehicle with travel pattern of continuing operational status with low exhaust temperature, a satisfactory NO x reduction effect can be attained even at exhaust temperature lower than that required conventionally therefor. In an exhaust emission control device with selective reduction catalyst 10 incorporated in an exhaust pipe 9, ammonia being added upstream of the catalyst 10 for reduction and purification of NO x , the device comprises an ammonia generator 12 with a vessel 15 for holding urea water 23a and with an electrode 16 for generation of ammonia 13a, 13b through action of plasma on the urea water 23a in the vessel, the ammonia 13a, 13b generated in the generator 12 being fed upstream of the catalyst 10.
摘要:
Disclosed is a urea solution reformer and an exhaust gas purifier using the same, configured to heat a carrier gas supplied from a carrier gas source by a carrier gas heating unit (16), to inject the carrier gas heated by the carrier gas heating unit from a carrier gas injecting nozzle (17), and to cause a urea solution (18) to be supplied by a first urea solution supply nozzle (21) to a tip end of the carrier gas injecting nozzle so that the urea solution is atomized by the carrier gas injected from the carrier gas injecting nozzle. Provided to face toward the carrier gas injecting nozzle is a catalyst unit (23) for decomposing the atomized urea solution to reform it into an ammonia gas. Further provided is an ammonia gas supply nozzle (24) attached to an exhaust pipe (12) of an engine so as to supply the ammonia gas discharged from an outlet of the catalyst unit into the exhaust pipe. The urea solution is sufficiently atomized, and thus reformed into an ammonia gas by the catalyst unit with a good efficiency.
摘要:
This exhaust purification device is provided with a reduction catalyst that reduces nitrogen oxides contained in exhaust. The reduction catalyst is provided with a catalyst layer and an adsorption layer covering the catalyst layer. The catalyst layer contains a catalyst support that supports silver. The adsorption layer contains a solid acid metal oxide that is acidic, and the acidity of the adsorption layer is greater than that of the catalyst layer. The adsorption layer has the characteristic of adsorbing ammonia generated at the catalyst layer, and causing the adsorbed ammonia to contact sulfur oxides contained in the exhaust.
摘要:
Incorporated in an exhaust pipe are an HC-SCR NO x catalyst capable of reducing NO x at temperatures less than a set temperature T and a catalyzed particulate filter with an oxidation catalyst capable of reducing NO x at temperatures not less than the set temperature T. When an exhaust gas temperature is less than the set temperature T, fuel with a set flow rate Q is intermittently added from a fuel addition unit on an entry side of the HC-SCR NO x catalyst to the HC-SCR NO x catalyst; when the exhaust gas temperature is not less than the set temperature T, the fuel with flow rate Q' not less than the set flow rate Q is temporarily rich-spike added from the fuel addition unit and is made arrival at a catalyzed particulate filter. With an active temperature range being expanded, exhaust emission control is performed in a wide temperature range.
摘要:
A carrier gas supplied from a carrier gas source is injected from a carrier gas injection nozzle. Also, a fuel including a hydrocarbon-based liquid and supplied from a fuel source is supplied to a tip end of the carrier gas injection nozzle, whereby this fuel is atomized with the carrier gas injected from the carrier gas injection nozzle. Furthermore, an inlet of a reforming part that decomposes the atomized fuel and reforms the atomized fuel into a reducing gas including either or both of hydrogen and an oxygen-containing hydrocarbon is provided so as to face the carrier gas injection nozzle and the fuel supply nozzle, and a reducing gas supply nozzle that supplies the reducing gas discharged from an outlet of the reforming part is provided in an exhaust pipe.
摘要:
The invention has an object of exerting favorable NO x reducing effects even at an exhaust temperature lower than in the prior art without trouble, e.g., at startup after long-term engine rest and is directed to an exhaust emission control device wherein a selective reduction catalyst 5 capable of selectively reacting NO x with ammonia even in the presence of oxygen is incorporated in an exhaust pipe 4, urea water 6 as reducing agent being added in the pipe 4 upstream of the reduction catalyst 5 to depurate NO x through reduction. It has an oxidation catalyst 9 arranged in the pipe 4 upstream of an added position of the urea water 6, the oxidation catalyst 9 having a feature of physically adsorbing NO x in the exhaust gas at a temperature lower than a lower active limit temperature of the reduction catalyst 5 and discharging the adsorbed NO x at a temperature higher than a lower active limit temperature of the oxidation catalyst 9, and means (a fuel injection device 14) for adding fuel into the exhaust gas 3 upstream of the oxidation catalyst, start of the fuel addition by the fuel addition means being refrained until exhaust temperature on an inlet side of the reduction catalyst 5 is increased to a preset temperature comparable with the lower active limit temperature of the oxidation catalyst 9.