Title:
CONTROL DEVICE FOR ELECTRICALLY HEATED CATALYST
Document Type and Number:
Japanese Patent JP3158988
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To heat an electrically heated catalyst to the aptitudinal temperature in an initial stage by supplying maximum power to the electrically heated catalyst for the specified time from the start of current application immediately after the start of an internal combustion engine, and then performing feedback control of power on the basis of the electric resistance value of the electrically heated catalyst.
SOLUTION: In the case of a current applying condition of an electrically heated catalyst(EHC) 5 being satisfied, and in the case of the specified time having elapsed after an alternator 9 is connected to the EHC 5, the electric resistance of the EHC 5 is measured to estimate the temperature of the EHC 5. The deviation between the measured electric resistance of the EHC 5 and the target electric resistance of the EHC 5 is obtained, and the correction duty value of a duty ratio for controlling the current quantity to the EHC 5 is obtained from the deviation. A final duty ratio is computed by adding the correction duty value to a present duty ratio, and the driving duty ratio of a transistor 12 is controlled to be gradually smaller so as to suppress excessive current application to the EHC 5.
Inventors:
Shinji Ikeda
Application Number:
JP23507095A
Publication Date:
April 23, 2001
Filing Date:
September 13, 1995
Export Citation:
Assignee:
TOYOTA JIDOSHA KABUSHIKI KAISHA
International Classes:
F01N3/20; F01N3/24; F01N9/00; H02J7/14; (IPC1-7): F01N3/20
Domestic Patent References:
| JP51526A | ||||
| JP681782A | ||||
| JP5312029A |
Attorney, Agent or Firm:
Takashi Ishida (3 others)
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