Variable-charger refers to a carburetor or injection device in which the fuel/air ratio can vary depending on the condition of the vehicle and the oxygen concentration in the exhaust gases. In a conventional carburetor, this cannot be achieved, since it does not have an appropriate control unit. Therefore, in this case, either an electronically controlled carburetor or an injection system is used.
The mixer receives control signals from a lambda probe, which is located in front of the catalyst or in the exhaust manifold and exhaust gas washer. The lambda probe is an electrical sensor that measures the concentration of oxygen contained in the exhaust gases and transmits a signal to the control unit in the form of a certain voltage level. In accordance with this signal, the control unit acts on the ratio of the components of the fuel mixture. On the one hand, this is necessary due to a change in the operating mode of the engine (idle, full throttle), on the other hand, a certain ratio is necessary in order to ensure the afterburning of exhaust gases in the catalyst.
In order for the afterburning of exhaust gases to take place in the catalyst at a temperature of 300-800°C, the fuel mixture must have more fuel than is necessary for clean combustion of the mixture in the cylinder. As a result, engines equipped with a catalytic converter have 5% higher fuel consumption.
The catalyst is located in the place of the additional muffler under the car tray. The catalyst is a monolithic ceramic honeycomb structure coated with platinum or rhodium. An elastic and temperature-resistant wire mesh is used to fasten the shock-sensitive ceramic housing.
The currently used catalysts are so-called ternary catalysts. This means that in such a catalyst, by means of exhaust gas feedback, three processes are simultaneously regulated: carbon monoxide oxidation (SO) and hydrocarbon (NS), as well as a decrease in the content of nitric oxide (NOx).
Rules for handling cars equipped with a catalyst
To avoid damage to the lambda probe and catalyst, be sure to follow these recommendations:
Refuel with unleaded gasoline only.
If the car is equipped with an additional catalytic converter, at least 2 full refuelings of unleaded gasoline are required before installation. In addition, for engines requiring the use of super gasoline, rearrange the ignition timing in the direction "Later", because the proposed unleaded supergasoline has a lower octane rating (ROZ 95). The ignition offset angle varies by model.
Starting the engine by pushing the vehicle or towing it is not allowed. Unburned fuel can ignite and cause the catalyst to overheat and break down. For this purpose, it is necessary to start the engine from an external source.
Frequently consecutive cold starts must be avoided. Otherwise, unburned fuel accumulates in the catalyst, which, after the engine warms up, burns explosively, destroying the catalyst.
If you have difficulty starting the engine, you should not press the starter for a long time, as unburned fuel accumulates as a result. It is necessary to find the cause of the poor start of the engine.
If malfunctions occur in the ignition, until a malfunction is found, remove the fuel pump or fuel injection control relay. This prevents fuel injection at start-up.
The spark test must not be carried out with the ignition plugs removed.
It is not possible to test the presence of ignition in individual cylinders by disconnecting the tips. When the ignition of any of the cylinders is turned off, unburned fuel enters the catalyst.
If ignition failures occur, their cause must be identified and established immediately, but without increasing the engine speed.
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