Air/fuel ratio detector
This patent describes a method for detecting the air/fuel ratio of exhaust gas with a detector comprising an electrochemical cell sensor element and an oxygen pump element. Each element is in the form of an oxygen-ion-conductive solid electrolyte having a porous electrode formed on both sides thereof. The electrochemical cell sensor element being disposed to face the pump element with a small gap therebetween, exposed to the exhaust gas and an air compartment which is open to the atmosphere being formed on that side of the pump element which is opposite to the small gap. An electric current is caused to flow through the oxygen pump element so that oxygen is pumped into the small gap from the air compartment or in the opposite direction, thereby producing an electromotive force in the sensor element. The electromotive force and the current flowing through the pump element is used as a basis for detecting the air/fuel ratio of the exhaust gas. The improvement described here is wherein a sufficient amount of current to pump oxygen from the air compartment into the small gap is caused to flow through the oxygen pump element so as to produce an abrupt change in the electromotive force of the sensor element at a stoichiometric air/fuel ratio. The electromotive force of the sensor element is used to determine whether a present air/fuel ratio is in the fuel-rich or fuel-lean region.
- Assignee:
- Mitsubishi Denki NGK Spark Plug Co., Ltd., Aichi
- Patent Number(s):
- US 4615787
- OSTI ID:
- 7142344
- Country of Publication:
- United States
- Language:
- English
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Air/fuel ratio detector
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Related Subjects
330700* -- Advanced Propulsion Systems-- Emission Control
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRIC MEASURING INSTRUMENTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTROCHEMICAL CELLS
ELECTRODES
ELECTROLYTES
ELECTROMOTIVE FORCE
ELEMENTS
ENGINES
EQUIPMENT
EXHAUST GASES
FLUIDS
FUEL-AIR RATIO
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
IONIC CONDUCTIVITY
MEASURING INSTRUMENTS
NONMETALS
OXYGEN
PHYSICAL PROPERTIES
POROSITY
PUMPS
SOLID ELECTROLYTES
STOICHIOMETRY
WASTES