초록 ▼

A method and apparatus for purifying an exhaust gas of an internal combustion engine includes an ammonia generating catalyst for generating ammonia from nitrogen oxides contained in the exhaust gas to be purified, and a nitrogen oxide reducing catalyst downstream of the ammonia generating catalyst,

A method and apparatus for purifying an exhaust gas of an internal combustion engine includes an ammonia generating catalyst for generating ammonia from nitrogen oxides contained in the exhaust gas to be purified, and a nitrogen oxide reducing catalyst downstream of the ammonia generating catalyst, for reduction of nitrogen oxides contained in the exhaust gas to be purified. Generated ammonia is used as the reducing agent. A nitrogen oxide adsorption catalyst is arranged upstream of the ammonia generating catalyst, or the ammonia generating catalyst is arranged in an exhaust pipe branch which pertains to only a part of several separately controllable internal-combustion sources. One or more additional exhaust pipe branches assigned to the other internal-combustion sources and lead to the nitrogen oxide reducing catalyst, while bypassing the ammonia generating catalyst. The part of the internal-combustion sources pertaining to the exhaust pipe branch of which contains the ammonia generating catalyst is operated either continuously or intermittently in a rich mode. Also, one or more combustion sources which feed their exhaust gas to the nitrogen oxide adsorption catalyst may be operated alternately in a lean and rich mode.

대표청구항 ▼

1. An exhaust gas purification system for purifying the exhaust gas of several separately controllable internal-combustion sources, comprising:an ammonia generating catalyst for generating ammonia from nitrogen oxides contained in the exhaust gas to be purified; a nitrogen oxide adsorption catalyst

1. An exhaust gas purification system for purifying the exhaust gas of several separately controllable internal-combustion sources, comprising:an ammonia generating catalyst for generating ammonia from nitrogen oxides contained in the exhaust gas to be purified; a nitrogen oxide adsorption catalyst for intermediate storage of nitrogen oxides contained in the exhaust gas to be purified; and a nitrogen oxide reducing catalyst arranged downstream of the ammonia generating catalyst, for reducing nitrogen oxides contained in the exhaust gas to be purified, while using the ammonia as the reducing agent which is generated in the ammonia generating catalyst, wherein the ammonia generating catalyst is arranged in an exhaust pipe branch pertaining to a first part of the internal-combustion sources and the nitrogen oxide adsorption catalyst is arranged upstream of the ammonia generating catalyst, which exhaust pipe branch leads to the nitrogen oxide reducing catalyst, and wherein at least one additional exhaust pipe branch is assigned to the other internal-combustion sources and leads to the nitrogen oxide reducing catalyst, while bypassing the ammonia generating catalyst and the nitrogen oxide adsorption catalyst.