RESISTANCE ADJUSTING TYPE HEATER, CATALYTIC CONVERTER AND METHOD OF CONTROLLING AUTOMOTIVE EXHAUST EMISSIONS

摘要

A resistance adjusting type heater comprises a honeycomb structure with at least two electrodes provided thereon to supply a current to the honeycomb structure and with a resistance adjusting means provided between the electrodes. The resistance adjusting means is formed such that a cross-section of a heating portion of the heater is substantially the same as that of a main monolithic adjusting heater which is disposed upstream or downstream of a main monolithic catalyst, or between main monolithic catalysts. A catalytic converter includes a first flow passage and a second flow passage to bypass the exhaust gas therethrough. The first flow passage contains a honeycomb heater or heater catalyst which comprises a honeycomb heater with a catalyst carried thereon. At the beginning of the operation, the exhaust gas whose temperature is low is caused to flow through the first flow passage. When the temperature of the exhaust gas exceeds a predetermined value, the flow passage is switched over from the first passage to the second flow passage. A catalytic converter includes a honeycomb heater disposed downstream of a main monolithic catalyst or between main monolithic catalysts. A catalytic converter includes honeycomb heaters which are respectively disposed upstream and downstream of a main monolithic catalyst.