Title:
SYSTEM FOR CATALYST DETERIORATION DIAGNOSIS
Document Type and Number:
Japanese Patent JP3157061
Kind Code:
B2
Abstract:
PURPOSE: To improve the precision of catalyst deteriorating state diagnosis by providing a state detecting means to detect a state quantity having correlation with the temperature of a portion that becomes the object of temperature detection and a surmise means to surmise the temperature of the detection object portion.
CONSTITUTION: An engine 2 is fitted with an intake pipe 30 to take in air and an exhaust pipe 32 to discharge gas after combustion as exhaust gas. A catalytic converter 4 is provided at the halfway point of the exhaust pipe 32. A catalyst diagnosis system is chiefly composed of a diagnosis device 8, various sensors to detect the operation state of the engine 2, and oxygen sensors 6a, 6b. The diagnosis device 8 possesses in the inside a catalyst state surmising means 80, a conversion efficiency calculating means 82 and a judging means 84. The judging means 84 prepossesses a reference limit value to show a deterioration limit at which a catalyst must be replaced, and conducts the judgment of a catalyst deteriorating state in comparison with the calculating outcome of the conversion efficiency calculating means 82. Thus, the precision of catalyst deteriorating state diagnosis can be improved.
Inventors:
Takashi Mukaihira
Toshio Ishii
Kiyoshi Miura
Kazuya Kawano
Toshio Ishii
Kiyoshi Miura
Kazuya Kawano
Application Number:
JP9976593A
Publication Date:
April 16, 2001
Filing Date:
April 26, 1993
Export Citation:
Assignee:
株式会社日立製作所
International Classes:
F01N3/20; F01N11/00; F02D45/00; F01N7/00; F01N9/00; F02D41/14; F02D41/22; (IPC1-7): F01N3/20; F02D45/00
Domestic Patent References:
| JP6212955A | ||||
| JP674025A | ||||
| JP6101455A | ||||
| JP6200750A | ||||
| JP5248227A | ||||
| JP4171231A | ||||
| JP4116212A | ||||
| JP2305309A | ||||
| JP227109A | ||||
| JP1232106A | ||||
| JP62203965A |
Attorney, Agent or Firm:
Kazuko Tomita