Exhaust gas control systems
All gasoline engines are designed to use unleaded gasoline to meet stringent exhaust gas requirements. All models are equipped with a crankcase gas management system and a catalytic converter to keep exhaust emissions to a minimum. All models are also equipped with an exhaust gas recirculation system (RVG) and a fuel vapor recovery system to further reduce engine toxicity.
All diesel engines are designed to meet stringent exhaust gas requirements. All diesel models are also equipped with a crankcase gas management system and a catalytic converter to keep exhaust emissions to a minimum. All models are also equipped with an exhaust gas recirculation system (RVG) to further reduce the toxicity of exhaust gases.
Crankcase ventilation system
To reduce the release of unburned hydrocarbons from the crankcase to the atmosphere, the blow-by gas control system is closed, blow-by gases and oil vapor are extracted from the crankcase and fed into the intake manifold through a wire mesh oil separator, for afterburning during normal combustion in the cylinders.
Gases are sucked out of the crankcase under the action of vacuum in the intake manifold. If the vacuum in the intake manifold is small, the gases are removed from the crankcase under the action of (respectively) increased pressure in the crankcase. With a worn engine, increased pressure in the crankcase causes gases to return to the intake manifold at all vacuums in it. To regulate the flow of blow-by gases, all diesel engines are equipped with a pressure regulating valve installed in the valve cover.
Emission Control - Petrol Models
To minimize the level of harmful emissions into the atmosphere, a catalytic converter is installed in the exhaust system. System - closed type with oxygen sensor (lambda probe), which provides feedback through the ECU of the engine. BEU regulates the composition of the mixture, creating optimal conditions for the operation of the catalytic converter.
The oxygen sensor has a built-in electric heating element, controlled by a command from the BEU through a relay to accelerate the sensor tip to the optimum operating temperature. The oxygen sensor sends a voltage signal to the BEU, which varies depending on the oxygen content in the exhaust gases: By depleting the mixture and increasing the oxygen content in the exhaust gases, the voltage increases. The peak voltage value is obtained at a stoichiometric mixture ratio of 14.7 parts (by weight) air and 1 part fuel. Around this value, the voltage from the sensor varies over a wide range, changing the width of the injector opening pulse. The removal and installation of the sensor is described in detail in chapter 4A.
Emission Control - Diesel Models
To minimize the level of harmful emissions into the atmosphere, a catalytic converter is installed in the exhaust system. In the neutralizer, gaseous hydrocarbons and carbon monoxide are burned up to the state of water and carbon dioxide.
All diesel engines are also equipped with an exhaust gas recirculation system (RVG). This system reduces the level of nitroxides in the exhaust gases by returning part of the exhaust gases back to the intake manifold through a plunger valve under certain operating conditions. The system is controlled by commands from the BEU.
Evaporative Emission System - Petrol Models
To minimize the evaporation of unburned hydrocarbons into the atmosphere, all gasoline models are equipped with a fuel vapor recovery system. The fuel tank is vented to the atmosphere through a carbon adsorber installed in the front right part of the engine compartment behind the bumper support. The adsorber captures fuel vapors from the tank when the car is parked and stores them until the engine is started and warmed up, purge valve (on command from BEU) will open and the vapors will enter the cylinders through the intake manifold, where they will burn out in the normal combustion mode.
In order not to re-enrich the mixture during warm-up and under load and not to disable the catalytic converter prematurely, the system purge valve opens and closes on command from the ECU.
Exhaust systems
On petrol models with ADP, ADR and AFY engines, the exhaust system consists of an exhaust manifold (with oxygen sensor), downpipe, catalytic converter, intermediate pipe with silencer and exhaust pipe with silencer. On AHL petrol models, the exhaust system consists of an exhaust manifold (with oxygen sensor), exhaust pipe with integrated catalytic converter, intermediate pipe with silencer and exhaust pipe with silencer. On petrol models AEB and AJL, the exhaust system consists of an exhaust manifold, a turbocharger, a catalytic converter with an oxygen sensor, a front pipe, an intermediate pipe with a silencer, and an exhaust pipe with a silencer.
On all diesel models, the exhaust system consists of an exhaust manifold, a turbocharger, a downpipe with an integrated catalytic converter, a short connecting pipe, an intermediate pipe with a silencer, and an exhaust pipe with a silencer. The system is suspended on rubber bushings and/or on rubber rings. The intermediate and rear parts of the muffler are manufactured as a whole, but they are also available separately for spare parts.
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