Lambda probe: device and purpose

The lambda probe sensor (or else, wordsmotorists, lambda probe) is a mechanism that is responsible for the concentration and ratio of gasoline and air in the fuel-air mixture during its preparation and supply through the fuel channels to the engine cylinder. From the correctness of the readings of this device depends the total fuel consumption, power and dynamics of the car. In fact, the importance of the sensor is comparable to the carburetor and the injector, since both take a direct part in the preparation of the fuel mixture. In today's article, we will find out what a lambda probe is, how it is arranged and what it is intended for.

Device

Основой (главным рабочим элементом) данного sensor is a porous ceramic material that is produced on zirconia dioxide. The very design of this device assumes the presence of the following parts:

• steel casing;
• cuffs of wires;
• ceramic insulator;
• contact of the heating circuit;
• wiring;
• O-ring;
• a tip made of zirconium ceramics;
• a rod with an incandescent spiral;
• an internal protective screen with a special hole for the exhaust gases;
• outdoor screen with a hole for the atmospheric air;
• current collector.

Where it is located?

Зачастую лямбда-зонд (ВАЗ-2110 в том числе) is located in the exhaust system, outside the exhaust manifold. You should also know that on some cars there can be two such devices. One of them can be placed before the catalyst, and the second - after it. The work of two lambda probes significantly improves the efficiency and accuracy of the preparation of the fuel-air mixture for its further supply to the combustion chamber of the internal combustion engine.

Operating principle

Алгоритм работы данного устройства основан на properties of zirconium oxide. Therefore, it is used at a temperature of at least 350 degrees Celsius. In some cases, in order to speed up the heating process, a special electric heater is used. The whole principle of the lambda probe can be divided into several stages:

1. Spent exhaust gases pass through the catalyst and the exhaust pipe. In this case, they flow around the working surface of the sensor of the lambda probe, which is located in front of the catalyst.
2. Further, this device analyzes the O2 level in the exhaust gas and compares the data with the level in the atmosphere.
3. During the sensor operation, a potential difference is generated, after which the mechanism sends a short electrical signal to the engine ECU.
4. After that, the computer processes the data and sends a signal to a certain number of devices, thereby regulating the operation of the actuators.

Следует отметить, что в случае нехватки кислорода in the system, namely in the fuel-air mixture, the combustion products are not oxidized to the end. In this case, the vehicle begins to lose momentum, and an increase in fuel consumption occurs (a depleted mixture forms in the chamber). If there is too much air in the system, this leads to an incomplete decomposition of nitrogen oxide, which is also not shown in the best way at the engine operation.