6.4. Systems of release and decrease in toxicity of the fulfilled gases
System of release of OG
The system of production of the fulfilled gases (OG) consists of final collectors, reception pipes, catalytic converters, exhaust silencers and an exhaust pipe.
Systems of decrease in toxicity of the fulfilled gases
The principle of functioning of a control system of the engine is constructed so that to receive the maximum return from the engine at the minimum fuel consumption and the maintenance of toxic components in OG. On considered cars are established system of catching of fuel evaporations (EVAP, only petrol models), system of ventilation of a case (PCV), system of circulation of OG (EGR) and system of a podmeshivaniye of additional air in (SAI) OG for the purpose of acceleration of a conclusion of not heated-up catalytic converter on an operating level (only to model with M60 and M73 engines).
System of operated ventilation of a case (PCV)
For elimination of leakages of not burned down hydrocarbons in the atmosphere the engine completely загерметизирован. Gases and pairs of oil which are forming in a case, move in the inlet pipeline and burn down in cylinders together with fuel.
Gases are removed from a case at the expense of a pressure difference in a case and the inlet pipeline (pressure in a case is higher).
System of catching of fuel evaporations (EVAP)
The EVAP system is intended for decrease in emission in the atmosphere of not burned down hydrocarbons. The jellied mouth of a fuel tank is tightly closed by a cover. In a coal absorber pairs of fuel which are forming in a tank during parking of the car gather, and keep there until on a signal of the control unit the absorber purge will not begin. During a purge of pair of fuel move via the purge valve in the inlet pipeline where they mix up with a working mix and further burn down usually in combustion chambers.
For ensuring normal operation of the engine on single turns and during warming up the control unit holds the valve the closed. Thus hit of not burned down fuel in the catalytic converter (is prevented at the raised turns of idling a mix переобогащена). After engine warming up the valve starts to open and be closed, regulating giving паров fuels to the inlet highway.
Since diesel fuel труднолетуче, on diesel models the filter with absorbent carbon is not used. Air removal from a fuel tank occurs directly in the atmosphere.
System of a retsirkulyatsiya of OG (EGR)
This system allows to reduce quantity of NOx in the fulfilled gases. For this purpose the small part of OG moves in the inlet pipeline via the special valve. The valve of system of a retsirkulyatsiya is supervised by the control unit.
Catalytic converter and lambda probes
For decrease in number of harmful emissions three-functional catalytic converters are built in the atmosphere in system of release of OG. The control system of injection of fuel has feedback in which are included a lambda probes, constantly informing the control unit about OG structure. Depending on the received data, the control unit corrects quality of the mix submitted to chambers of combustion and, thus, optimizes conditions of combustion of fuel.
The working surface a lambda probes is sensitive to change of the content of oxygen in OG. Depending on its concentration target tension of the sensor changes. If a mix переобогащена (the content of oxygen in OG very low), the lambda probe submits signals with a low voltage. Tension increases in process of pauperization of a mix and increase in the content of oxygen in gases. Most effectively the converter works at optimum composition of gas mixture (14.7 parts of air for 1 part of fuel).