Pic. 3.95. Exhaust system: 1 - oxygen concentration sensors, 45 Nm; 2 - clamp, 25 Nm
The exhaust system consists of an exhaust manifold, exhaust pipe, mufflers and a catalytic converter (pic. 3.95).
Elements of the exhaust system are connected with clamps.
Attention! The connection element in the exhaust pipe must be protected from any mechanical damage. The connecting element in the exhaust pipe must not be bent by more than 20°in the angle of rotation or displaced by 20 mm in the axial and 25 mm in the radial directions, otherwise it will be damaged.
Catalytic converter
All cars are equipped with catalytic converters to reduce the amount of harmful substances emitted into the atmosphere with exhaust gases.
The inlet and outlet cones with branch pipes and mounting flanges, as well as heat reflectors holding the ceramic lining, are welded to the stainless steel body of the neutralizer. The entire internal volume of the housing is occupied by a porous ceramic catalyst monolith fixed by stainless steel rings or mesh. The catalyst is a filter in which the entire inner and outer surface of the pores in contact with gases is covered with a very thin layer of an alloy that contains platinum, rhodium and palladium. The porous catalyst has a large surface area coated with this alloy of very expensive metals, which mainly determines the high price of catalytic converters.
A reaction takes place in the catalyst, as a result of which potentially dangerous hydrocarbons and carbon monoxide in the exhaust gases are converted into harmless gases and water vapor.
On all models with a converter, the fuel supply system is of a closed type, that is, based on a signal from an oxygen concentration sensor installed in the exhaust system, the control unit constantly optimizes the composition of the air-fuel mixture.
The catalytic converter works effectively at a temperature of +300…+800°C.
Operation of vehicles with a catalytic converter
The catalytic converter is a reliable and simple device that does not require maintenance. In order to maximize its service life, the following safety precautions must be observed.
Do not use leaded gasoline in a vehicle equipped with a catalytic converter, as the lead will coat the precious metals in the catalyst grid, reducing their effectiveness and eventually damaging the catalyst.
Always keep the ignition and power systems in good condition.
Do not operate a vehicle with a faulty ignition system until the fault is corrected.
If the engine control warning lamp lights up while the engine is running, contact a service station as soon as possible. If the engine management system is damaged, then in addition to increasing fuel consumption and deteriorating the dynamic characteristics of the engine, the catalytic converter may fail.
Do not start the engine by towing.
Do not turn off the ignition at high engine speeds.
Do not use fuel and engine oil additives as they may contain substances that can damage the catalytic converter.
Do not drive the vehicle if blue smoke is emitted from the exhaust pipe.
After stopping the engine, the exhaust system continues to radiate heat for a long time, so you should avoid parking the car on grass and dry leaves.
Remember that the converter is fragile, so avoid shock when removing it or other elements of the exhaust system.