Saab 9-5

Since 1997 of release

Repair and car operation

Systems of release and decrease in toxicity of the fulfilled gases

The general information

System of release ОГ

The system of release of the fulfilled gases consists of final collectors, reception pipes, каталитических converters, mufflers 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 minimum the expense of fuel and the maintenance of toxic components in ОГ. The system of catching of fuel evaporations established on petrol engines (EVAP) prevents hit of last of a fuel tank in atmosphere.

Arrangement of components of system EVAP

On petrol engines V6 the system подмешивания air in ОГ (SAI) for the purpose of acceleration of a conclusion not heated-up catalytic the converter on an operating level is used also.

System подмешивания air in fulfilled gases

On all models the ventilation system картера (PCV) is established also. Components of systems of decrease in toxicity ОГ of the diesel engine and their arrangement are specified in illustrations.

Components of systems of decrease in toxicity ОГ of the diesel engine

On diesel engines system EGR is used.

System of operated ventilation картера (PCV)

For elimination of leaks of not burnt down hydrocarbons in atmosphere the engine completely загерметизирован. Gases and steams of oil formed in картере, move in the inlet pipeline and burn down in cylinders together with fuel.

Gases leave from картера for the account of a difference of pressure in картере and the inlet pipeline (pressure in картере above).

System of catching of fuel evaporations (EVAP)

System EVAP is intended for emission decrease in atmosphere of not burnt down hydrocarbons. The jellied mouth of a fuel tank is tightly closed by a cover. In a coal adsorber steams of fuel formed in a tank during parking of the car gather, and are kept there until on a signal of the block of management the adsorber purge will not begin. During a purge of pair fuel move through the purge valve in the inlet pipeline where they mix up with a working mix and further burn down in the usual image in combustion chambers.

For maintenance of normal work of the engine on single turns and during warming up the management block holds the valve the closed. Thus hit of not burnt down fuel in каталитический the converter (is prevented at the raised turns of idling a mix переобогащена). After warming up of the engine the valve starts to open and be closed, regulating giving of steams of fuel in an inlet path.

The Katalitichesky converter and ljambda-probes

For decrease in quantity of harmful emissions atmosphere in release system are built in трёхфункциональные каталитические converters. The control system of fuel injection has a feedback in which the ljambda-probes constantly informing the block of management about structure OG are included. Depending on the received data, the management block corrects quality of the mix submitted to the chambers of combustion and, thus, optimises fuel combustion.

In a ljambda-probe established for каталитическими by converters, the heating element included by the block of management through the special relay is built in. The working surface of a ljambda-probe is sensitive to change of the maintenance of oxygen in ОГ. Depending on its concentration target pressure of the gauge varies. If the mix переобогащена (the oxygen maintenance in the fulfilled gases very low), a ljambda-probe submits signals with a low voltage. Pressure increases in process of pauperisation of a mix and increase in the maintenance of oxygen in gases. Most effectively the converter works at optimum structure of a gas mixture (14.7 parts of air on 1 part of fuel). At optimum concentration of oxygen in ОГ there is a jump in pressure on a ljambda-probe. This jump is a reference point for the management block at updating of quality of a mix.

System подмешивания air in ОГ (SAI)

The given system is intended for warming up acceleration каталитических converters and, hence, their conclusion in operating conditions. For warming up it is used warmly, allocated during reaction of oxygen containing in submitted air with the fulfilled gases (CO and HC). Air moves in final collectors special pump SAI which joins if the temperature of soaked up air and ОЖ makes from-9 to +30 hailstones, pressure of the battery no more than 16 In, and the stream of soaked up air does not surpass 700 mg/step of combustion. Besides, before the beginning of work of the pump the engine should make from 40 to 75 full cycles, depending on temperature ОЖ. For the purpose of prevention of sudden jump of toxicity ОГ at system SAI deenergizing, pump SAI continues to work during 15 cycles of the engine after the necessity termination in подмешивании air. At work of system SAI for indemnification of additional air the volume of injected fuel also increases.

For prevention of leak ОГ through system SAI in each block of cylinders the control valve closed at deenergizing of pump SAI is established.

System рециркуляции ОГ (EGR)

This system allows to lower quantity NO _x in the fulfilled gases. For this purpose small part ОГ moves in the inlet pipeline through the special valve. The system valve рециркуляции is supervised by the management block.