Exhaust system
As part of a refurbishment, each section of the exhaust system can be replaced individually.
Emission Control System
Petrol models
Attention! Only unleaded petrol must be used in the fuel systems of all petrol models!
The principle of operation of the engine management system is designed to obtain maximum output from the engine with minimum fuel consumption and content of toxic components in the exhaust gases. The fuel vapor capture system prevents the latter from entering the atmosphere from the fuel tank. An exhaust gas recirculation system is also installed.
Controlled Crankcase Ventilation (PCV) System
To eliminate leaks of unburned hydrocarbons into the atmosphere, the engine is completely sealed. Gases and oil vapors formed in the crankcase enter the intake manifold through a mesh filter and burn in the cylinders together with the fuel.
Gases are removed from the crankcase due to the pressure difference in the crankcase and the intake manifold (crankcase pressure is higher).
Exhaust Gas Recirculation (EGR) System
The exhaust gas recirculation system reduces the amount of NO X in the exhaust gases. To do this, a small portion of the exhaust gases is fed into the intake manifold through a special valve. The recirculation system valve is controlled by the control unit.
Evaporative Emissions (EVAP) System
To reduce the emission of unburned hydrocarbons into the atmosphere, all petrol models are equipped with a fuel recovery system. The fuel filler neck of the fuel tank is hermetically sealed with a lid, and a carbon adsorber is installed under the fuel tank. It collects fuel vapors that form in the tank when the car is parked and stores them there until the control unit signals the filter to start purging. Then the fuel vapors begin to be supplied through the purging valve(s) into the intake manifold, where they mix with the working mixture and then burn in the usual way in the combustion chambers.
To ensure normal engine operation at idle speed and during warm-up, the control unit keeps the valve closed. This prevents unburned fuel from entering the converter (at high idle speed the mixture is too rich). After the engine warms up, the valve begins to open and close, supplying fuel vapors into the intake tract.
Catalytic converter and lambda probes
To reduce harmful emissions into the atmosphere, all petrol models have a three-function catalytic converter built into the exhaust system. The fuel injection control system has a feedback loop that includes an oxygen sensor. This sensor, installed in the exhaust system, constantly informs the control unit about the composition of the exhaust gases. Depending on the data received, the control unit adjusts the quality of the mixture supplied to the combustion chambers and thus optimizes fuel combustion.
The lambda probe has a built-in heating element, which is switched on by the control unit via a special relay. The working surface of the lambda probe is sensitive to changes in the oxygen content in the gases. Depending on the oxygen concentration, the sensor sends signals of different voltages. If the mixture is over-enriched - the oxygen content in the exhaust gases is very low, the sensor sends signals with low voltage. The voltage increases as the mixture becomes leaner and the oxygen content in the gases increases. The converter works most effectively with an optimal composition of the combustible mixture (14.7 parts air to 1 part fuel). When the oxygen concentration in the exhaust gases changes near the optimum value, a jump in the sensor voltage occurs. This jump is the starting point for the control unit when adjusting the mixture quality.
Two sensors are installed: one before and one after the catalytic converter assembly. This allows for more accurate monitoring of the exhaust gas composition.
Diesel models
The principles of operation of the diesel engine control system are based on the same requirements as for gasoline units. To further reduce the toxicity of gases, several auxiliary systems are installed on the car. The crankcase ventilation system reduces gas leaks into the atmosphere from the engine lubrication system. The catalytic converter reduces the toxicity of exhaust gases. An exhaust gas recirculation system is installed.
Controlled Crankcase Ventilation (PCV) System
To eliminate leaks of unburned hydrocarbons into the atmosphere, the engine is completely sealed. Gases and oil vapors formed in the engine crankcase are passed through a mesh filter, directed into the intake manifold and burned in the cylinders during normal engine operation
The removal of crankcase gases is achieved due to the difference in pressure in the crankcase and the intake manifold.
Catalytic converter
To reduce the amount of harmful emissions into the atmosphere, all diesel models have a catalytic converter built into the exhaust system. It neutralizes most of the gaseous hydrocarbons, carbon monoxide (CO) and other toxic impurities contained in the combustion products of the air-fuel mixture.
Exhaust Gas Recirculation (EGR) System
All diesel models are also equipped with an exhaust gas recirculation system, the main task of which is to reduce the percentage of nitrogen oxides (NOX) in the engine combustion products. To accomplish this task, a small portion of the exhaust gases from the exhaust system tract is redirected through a special valve to the intake manifold (see also Section General information). The operation of the EGR valve is controlled by the control unit.