The oxygen sensor is located in the exhaust manifold between the turbo and catalytic converter. It measures the amount of oxygen in the exhaust stream, allowing the ECM to compensate to some degree for various fuel grades, engine wear, altitude changes, usage of oxygenated fuel, and more. Another big benefit is the ability to keep emissions of carbon monoxide, oxides of nitrogen, and unburned hydrocarbons as low as possible.
TECHNICAL INFORMATION
STOECHIOMETRIC PROPORTION
Ideal air/fuel ratio:
• Gasoline – 14.7:1 (14.7 parts of air for 01 part of gasoline)
• Alcohol – 9.0:1 (9.0 parts of air for 01 part of alcohol)
• Diesel – 15.2:1 (15.2 parts of air for 01 parts of diesel)
SWITCHING
The transition of the Oxygen Sensor output signal from rich to lean mixture is called switching.
a) rich mixture
b) lean mixture
RICH MIXTURE
When the engine is working with a RICH mixture very little oxygen will be found among the exhaust gases, because almost all oxygen will have been consumed in the combustion of the excess injected fuel.
The result will be a low quantity of oxygen ions in the external electrode leading to a higher voltage generation.
LEAN MIXTURE
On the other hand, when the engine is working with a LEAN mixture, more oxygen will be found in the exhaust gases because of the lack of fuel to burn all the injected oxygen. This will lead to a higher quantity of oxygen ions in the external electrode, resulting in the generation of a smaller voltage.
The fuel injection control unit (computer) doesn’t use the sensor signal when:
- The engine is cold, because during this period the mixture must be rich.
- In fast acceleration or in full load.
- During cut-off, because during this period the mixture must be poor.
Catalogo Download
RUMIKO Oxygen Sensor Direct Fit Buyers Guide 
RUMIKO Oxygen Sensor OE Interchange
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