All diesel models are equipped with a quarry ventilation system. Additionally, to reduce harmful emissions, some models are equipped with a catalytic converter and an EGR system.
Crankcase blowout prevention
To reduce the release of unburned hydrocarbons from the crankcase to the atmosphere, a forced crankcase ventilation system is used. at the same time, the engine is sealed, and the gases that have broken into the crankcase, as well as oil vapors, are removed from the crankcase through the oil separator into the intake tract to be burned in the engine combustion chamber.
At high vacuum in the collector (idling, deceleration) gases will be forcibly sucked from the crankcase. At low vacuum in the collector (acceleration. full throttle opening) gases are pushed out of the crankcase (relatively) higher pressure in the crankcase; if the engine is worn out, increased crankcase pressure (due to increased gas breakthrough) will force the gases to return to the intake manifold under any of its conditions.
Reduced exhaust emissions
To minimize the amount of pollutants released into the atmosphere, all models are equipped with a catalytic converter in the exhaust system. The control system is built on a closed type, in which the oxygen sensor in the exhaust system provides the fuel injection system electronic control unit with constant feedback on the oxygen content in the exhaust gases. This allows the electronic control unit to adjust the mixture by changing the injection duration, thus providing the best conditions for the operation of the converter.
oxygen sensor (Lambda probe) has a built-in heating element activated by the electronic control unit, allowing the sensitive element of the sensor to reach the effective operating temperature faster. The sensor is sensitive to oxygen and sprinkles a varying voltage on the control module depending on the amount of oxygen in the exhaust gases; if the engine inlet mixture is too rich, the exhaust gases contain little oxygen, so the sensor sends a voltage proportional to the amount of oxygen detected, when the mixture is lean, the voltage changes as the amount of oxygen in the exhaust gases increases. The highest conversion efficiency of all major pollutants occurs when the composition of the working mixture is maintained in the chemically correct ratio for complete combustion of gasoline - 14.7 parts by weight of air per part of fuel ("stoichiometric" coefficient). The voltage at the output of the sensor around this point changes in large steps, the electronic control unit uses the signal change to adjust the working mixture by changing the opening time of the nozzles. Details of removal and installation of the Lambda probe are described in Chapter 4B.
Some models use an auxiliary air intake system that is designed to reduce the emission of gaseous hydrocarbons and carbon monoxide. A mechanical type air pump, driven by the accessory drive belt, forces air into the exhaust manifold where it mixes with particles of partially burned fuel. Oxygen-enriched air mixes with pollution and allows it to be oxidized by converting some of the hydrocarbons and carbon monoxide into harmless carbon dioxide and water vapour.
The exhaust gas recirculation system is installed on models for certain markets. It reduces the level of nitrogen oxides that are formed during the combustion of fuel by returning part of the exhaust gases through the valve back to the intake manifold, under certain engine operating conditions. The system has an electro-pneumatic drive and is controlled by an electronic control unit (ECU).
Emission Control System - Diesel Models
For some markets, on models with diesel engines, an oxidation catalyst is installed in the exhaust system. This makes it possible to destroy a large proportion of gaseous hydrocarbons and carbon monoxide, which are present in the exhaust gases. For certain markets, a trap is built into the muffler, which allows you to trap particulate hydrocarbons that are suspended in the exhaust gases. Certain diesel models are equipped with an EGR system.
The exhaust gas recirculation system reduces the level of nitrogen oxides that are formed during the combustion of fuel by returning part of the exhaust gases through the valve back to the intake manifold under certain engine operating conditions. The system has an electro-pneumatic drive and is controlled by an electronic control unit (ECU).
Evaporative Emission System - Gasoline Models
To reduce the ingress of hydrocarbons from the power system into the atmosphere, a gasoline vapor recovery system is installed on all gasoline models. The filler cap of the gas tank is sealed and an absorber filled with activated carbon is built under the left fender, which captures gasoline vapors from the gas tank (and on carburetor models from the float chamber).
The absorber retains vapors until the electric purge valve opens, controlled by the fuel injection/ignition control system controlled by the electronic control unit. When the valve opens, the vapors are sucked into the intake tract and then burned in the engine.
The flow of gasoline vapor from the absorber through the valve to the throttle chamber is controlled by a thermal valve, which does not allow the purge valve to open until the temperature of the coolant reaches a certain value. This is necessary to ensure that the engine runs normally when it has not yet warmed up and to protect the catalytic converter from a rich mixture. Additionally, since the purge valve is controlled by intake manifold vacuum, the absorber only opens when the engine is under load. This allows you to prevent over-enrichment of the mixture when idling and driving at low speed.
Exhaust systems
The exhaust system consists of an exhaust manifold, a set of mufflers and intermediate pipes (depends on model and specification), catalytic converter (where it is installed) and a set of support brackets and rubber feet.
The turbocharger, which is fitted to the turbocharged model, is oil-cooled and has a built-in pressure relief valve. In the event of failure of the compressor pressure control valve, the overload safety valve (controlled by a switch mounted on the intake manifold) opens and limits the amount of fuel supplied to the engine through an actuator mounted on the high pressure fuel pump.