The special ceramics of the probe are exposed to exhaust gases on the outside, and are in contact with atmospheric air on the inside.
Here is a schematic representation of the operation of a catalytic converter. NOx emissions are released from the engine (nitrogen oxides), SO (carbon monoxide) and NS (hydrocarbons). After the reaction, N ₂ (nitrogen), CO ₂ come out of the catalytic converter (carbon dioxide) and H 2 O (water).
Left: In the Vectra's 1.6-liter, eight-valve engine, the lambda probe (arrow) is located directly in the exhaust manifold. The lambda probe removal procedure is described in the chapter on injection.
Right: the plug connection for the lambda probe wires is located on the right side of the engine under the DIS ignition module.
Due to the different oxygen content in the exhaust gases and in the atmospheric air, the probe creates a voltage that increases sharply at a certain content of residual oxygen in the exhaust gases. This voltage jump occurs exactly at that ratio of fuel and air when λ=1. With a lack of oxygen (λ is less than 1), i.e. with a rich fuel-air mixture, the voltage is 0.9-1.1 V. With a lean fuel-air mixture (λ is greater than 1) 0.1 V is reached.
The lambda signals are sent to the injection system control unit. From there, the fuel-air mixture is influenced in order to maintain the fuel-air ratio as close as possible to λ=1.
The lambda probe reacts to fluctuations in the amount of oxygen depending on its operating temperature at different speeds: at 300°C it reacts in about 1 second, at 600°C in less than 50 ms. O Due to the built-in heating in 1.8-2.0 l engines, the most favorable operating temperature of about 600°C is reached faster.
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