The fuel injection system receives control signals from a lambda probe, which is located in front of the catalyst in the exhaust pipe and is washed by the exhaust gas stream. The lambda probe is an electrical measuring sensor that indicates the residual oxygen content in the exhaust gases by voltage fluctuations and allows you to draw a conclusion about the composition of the air-fuel mixture. Within fractions of a second, the lambda probe transmits the appropriate signals to the fuel injection system control unit, while constantly changing the air-fuel mixture ratio. On the one hand, this is required as a result of constantly changing operating conditions (idle, full throttle), on the other hand, due to the additional combustion of fuel in the catalyst, since there is still a sufficient amount of it in the exhaust gas.
In order for the fuel to burn out in the catalyst at temperatures from +300°to 800°C, the air-fuel mixture must contain a larger proportion of gasoline than is required for clean combustion. As a result, a car with a catalyst has a 5% higher fuel consumption.
The catalytic converter is located in place of the additional muffler under the bottom of the machine. The catalyst consists of a honeycomb-shaped ceramic body coated with platinum or radium. The fragile ceramic case is placed in an elastic heat-resistant wire cloth.
The installed conventional catalyst is a 3-way catalyst. This means that with such a catalyst, thanks to the lambda regulation, carbon monoxide is simultaneously oxidized (SO) and hydrocarbons (NS), as well as a decrease in the content of nitric oxide (NOx).
In order to avoid damage to the lambda probe and catalytic converter, the following instructions must be observed:
- fill only unleaded gasoline;
- starting the engine by towing or pushing is unacceptable: unburned fuel can lead to overheating of the catalyst and its failure. A second battery must be used;
- frequent cold starts should be avoided. Since unburned fuel accumulates in the catalyst, it burns explosively when ignited and leads to catalyst failure;
- in case of poor starting, do not turn on the starter for a long time unnecessarily. Find and fix the problem;
- in the absence of ignition in some cylinders, avoid high engine speeds. If there is no ignition in any cylinder (when testing the engine) unburned fuel enters the catalyst;
- do not park the car over dry leaves or grass. The exhaust system in the area of the catalyst has a high temperature;
- When filling or topping up engine oil, take special care to ensure that the oil is never filled too high "max" marks on the oil level indicator. Excess oil, due to incomplete combustion, will enter the catalyst and can destroy it.
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