Title:
AIR-FUEL RATIO DETECTION DEVICE
Document Type and Number:
Japanese Patent JP2018048624
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide an air-fuel ratio detection device capable of suppressing an increase in environmental load.SOLUTION: A parallel circuit 38 is provided in parallel with a resistor 20 for current detection that is connected to an air-fuel ratio sensor 100 in series. The parallel circuit has a first switch 40 and a constant current source 42. A second switch 44 is provided between the resistor and the air-fuel ratio sensor. In air-fuel ratio detection control time that is a first period, the first switch is controlled to an off state and the second switch is controlled to an on state, and in deterioration detection control time that is a second period, the first switch is controlled to an on state and the second switch is controlled to an off state. Due to this configuration, in the deterioration detection control time, the constant current source is electrically connected to the resistor to cause a predetermined current to flow in the resistor. Therefore, based on an A/D conversion result of a voltage between both ends of the resistor, occurrence of deterioration can be detected.SELECTED DRAWING: Figure 1
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Inventors:
KOHARA TOMOHIRO
KAWASE YOSHIYUKI
KUROKAWA KAZUNORI
KAWASE YOSHIYUKI
KUROKAWA KAZUNORI
Application Number:
JP2017112957A
Publication Date:
March 29, 2018
Filing Date:
June 07, 2017
Export Citation:
Assignee:
DENSO CORP
International Classes:
F02D45/00; F02D41/14; F02D41/22; G01N27/26; G01N27/409
Domestic Patent References:
| JP2010008121A | 2010-01-14 | |||
| JP2013096880A | 2013-05-20 |
Foreign References:
| US6160404A | 2000-12-12 |
Attorney, Agent or Firm:
Kazuyuki Yahagi
Taihei Nonobe
Takanori Kubo
Taihei Nonobe
Takanori Kubo
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