Catalyst deterioration detecting apparatus and exhaust emission control device failure detecting apparatus
US5727383A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 1996 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Feb 2, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An exhaust pipe of an internal combustion engine is equipped with a three-way catalytic converter. Provided upstream and downstream the converter are an A/F sensor and a downstream O2 sensor, respectively. A CPU executes air-fuel feedback control according to the readings from the A/F sensor. When the period of air-fuel ratio inversion by the downstream O2 sensor has exceeded a predetermined time, the CPU determines that the three-way catalytic converter is activated. At that point, the CPU estimates the quantity of heat required from the start-up of the engine up to catalyst activation. The quantity of heat is obtained by accumulating the intake air quantity from the start of the engine up to catalyst activation (i.e., accumulated intake air quantity). Given the accumulated quantity of heat calculated, the CPU determines accordingly whether the three-way catalytic converter has deteriorated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.