EXHAUST GAS PURIFYING METHOD

PROBLEM TO BE SOLVED: To enable purification of NOx at a stable and high purifying rate in low to high temperature ranges. SOLUTION: A plurality of catalysts including at least two NOx occlusion/ reduction type catalysts are arranged in serial, and the temperature of an exhaust gas Tn flowing into t...

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Bibliographic Details
Main Author ISHIBASHI KAZUNOBU
Format Patent
LanguageEnglish
Published 09.05.2002
Edition7
Subjects
BLASTING
CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY
COMBUSTION ENGINES
CONTROLLING COMBUSTION ENGINES
ENGINE PLANTS IN GENERAL
GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES
GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL
HEATING
HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
LIGHTING
MACHINES OR ENGINES IN GENERAL
MECHANICAL ENGINEERING
PERFORMING OPERATIONS
PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
SEPARATION
STEAM ENGINES
THEIR RELEVANT APPARATUS
TRANSPORTING
WEAPONS
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Summary:PROBLEM TO BE SOLVED: To enable purification of NOx at a stable and high purifying rate in low to high temperature ranges. SOLUTION: A plurality of catalysts including at least two NOx occlusion/ reduction type catalysts are arranged in serial, and the temperature of an exhaust gas Tn flowing into the nth NOx occlusion/reduction type catalyst countered from upstream is set within the formula (1) Tn=Tn-1-ΔT-Tn-1-ΔT/2 wherein ΔT represents the difference between a maximum temperature where the nth NOx occlusion/reduction type catalyst can purify NOx, 80% of it or more and its lowest temperature, and Tn-1 represents the temperature of the exhaust gas flowing into the n-1st catalyst. The upstream catalyst can purify NOx at a low temperature, while the downstream catalyst can purify at a high temperature.
Bibliography:Application Number: JP20000317814