2. Please note: Leaded gasoline is not allowed.
Crankcase ventilation control
3. To reduce the release of unburned hydrocarbons from the crankcase to the atmosphere, the engine is sealed, and the gases that have broken into the crankcase and oil vapor are removed from it through the oil separator into the intake manifold, from where they enter the cylinders and burn there in the usual way.
4. The pressure in the crankcase is always slightly higher than in the intake manifold, so gases from the crankcase are sucked into the manifold. If the engine is very worn out, then the gases escaping into the crankcase have excess pressure and, under the influence of this pressure, also enter the intake manifold. Thus, gases will always enter the collector under any circumstances.
Exhaust gas management
5. To reduce harmful components in the exhaust gases, a catalytic converter is installed on all models, which is part of the exhaust system. The mixture composition control system has feedback through one or two oxygen sensors located before and after the converter. Sensors constantly inform the BEU about the amount of oxygen in the exhaust gases, which allows you to control the composition of the mixture in such a way as to provide the best conditions for the operation of the converter,
6. The oxygen sensor is equipped with a heating element, which allows the sensor to reach the desired temperature and start working faster. The tip of the sensor is sensitive to oxygen and, depending on its amount, sends a voltage of various levels to the BEU. If the working mixture is too rich, the exhaust gases contain little oxygen and the sensor sends a low level signal to the ECU. When the mixture is lean, the proportion of oxygen in the exhaust gases increases and the sensor sends a high level signal to the ECU. The best neutralization of all harmful components in the exhaust gases is achieved when the composition of the working mixture corresponds to the chemically necessary fuel-air ratio for complete combustion of the fuel. This mixture consists of 14.7 parts of air (by weight) and 1 part gasoline (this ratio is called stoichiometric). The voltage at the output of the oxygen sensor at this point changes especially sharply, so the BEU can very accurately control the composition of the mixture by changing the duration of the injector opening pulse.
Fuel vapor management
7. To reduce the possibility of unburned hydrocarbons entering the atmosphere, all models are equipped with a fuel vapor management system. The neck of the fuel tank is hermetically sealed, and fuel vapors from the tank enter the charcoal filter through the ventilation hose (absorber), located under the bottom at the rear of the vehicle. In the carbon filter, fuel vapors accumulate while the car is parked. When the engine is running, the BEU opens the filter purge valve, through which the accumulated fuel vapors enter the intake manifold and burn out in the engine cylinders.
8. To ensure normal operation of the engine during warm-up and at idle, the carbon filter purge valve is closed so as not to over-rich the mixture. The valve opens only when the engine reaches operating temperature and only when running under load.
Secondary air injection system
9. 4-cylinder engines and M52TU engines are equipped with this system. The purpose of the system is to reduce the warm-up time of the catalytic converter. For normal operation, the catalytic converter must have a temperature of at least 300°C. This temperature level is maintained by constantly hot exhaust gases passing through the converter. In order for the catalytic converter to reach this temperature level faster, clean air is mixed into the exhaust gases behind the exhaust valves. Such an oxygen-enriched mixture allows afterburning in the manifold and in the exhaust system all the fuel that has not had time to burn out in the engine cylinders. The temperature of the exhaust gases rises and warms up the converter faster. The system only works on cold start (up to 33°С) and turns off after about 2 minutes.