Table of contents: Crankcase ventilation system ↓ Catalytic converter ↓ Fuel Evaporation Control System ↓ Lambda sensor ↓ Exhaust Gas Recirculation (EGR)… ↓
Although proper ignition timing and mixture quality will minimize the amount of harmful gases released by the exhaust system, increasingly stringent regulations require the introduction of additional necessary systems.
Crankcase ventilation system
Some combustion products pass by the piston rings and enter the crankcase, from where they would be emitted into the atmosphere if special precautions were not taken.
To prevent them from escaping into the atmosphere, the crankcase breather is connected by a hose to the air filter so that the crankcase gases mix with the air/fuel mixture in the manifold and are burned in the engine
Catalytic converter
It consists of an additional component in the muffler system and exhaust pipe
The converter contains a catalyst that accelerates the chemical reaction that breaks down carbon monoxide and hydrocarbons in the exhaust gas into carbon dioxide and water.
The converter does not require any maintenance, but it should be periodically checked for signs of mechanical damage.
The catalytic converter in the converter can become ineffective due to the presence of fuel additives, so it is important to use only unleaded gasoline and that the fuel does not contain harmful additives.
The catalytic converter contains a ceramic insert that is very fragile and can break if the converter is dropped.
Fuel Evaporation Control System
To prevent fuel vapor from escaping into the atmosphere, the fuel tank is equipped with a carbon filter. The fuel tank has an expansion tank and ventilation tubes that are positioned so that fuel or vapor cannot escape, even if the vehicle is operated at very high ambient temperatures.
The vent tubes are connected to a canister containing carbon that absorbs fuel vapor. When the engine is not running, the fuel vapor is collected in the carbon canister. When the engine is running, fresh air is sucked in through the canister and the vapor is expelled from it to the air filter and then into the engine where it is burned. The canister is sometimes called a carbon canister.
Lambda sensor
Models equipped with a catalytic converter are able to monitor the amount of oxygen in the exhaust gases using a Lambda sensor in the exhaust manifold. Based on this information, the electronic control unit maintains the air/fuel mixture ratio at a constant level to ensure complete combustion.
Exhaust Gas Recirculation (EGR) System
Models with PS engine and automatic transmission are equipped with an EGR system, where some of the exhaust gases are returned to the intake manifold and burned.