Saab 9-5

since 1997 of release

Repair and car operation

Systems of release and decrease in toxicity of the fulfilled gases

General information

System of release of OG

The system of production of the fulfilled gases 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. The system of catching of fuel evaporations (EVAP) established on petrol engines prevents hit of last of a fuel tank in the atmosphere.

Arrangement of components of EVAP system

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

System of a podmeshivaniye of air in fulfilled gases

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

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

On diesel engines the EGR system is used.

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 adsorber 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 adsorber 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.

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. 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 fuel combustion.

In a lambda probe, established behind catalytic converters, the heating element which is switched on by the control unit through the special relay is built in. The working surface a lambda probe 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 the fulfilled gases 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). At optimum concentration of oxygen in OG there is a jump in tension on a lambda probe. This jump is a reference point for the control unit at correction of quality of a mix.

System of a podmeshivaniye of air in (SAI) OG

This system is intended for acceleration of warming up of catalytic converters and, therefore, their conclusion in an operating mode. For warming up heat allocated during reaction of oxygen containing in submitted air with fulfilled gases (by CO and HC) is used. Air moves in final collectors the special pump SAI which joins if the temperature of soaked-up air and OZh makes from-9 to the +30th hail, tension of the battery no more than 16 In, and the stream of soaked-up air does not surpass 700 mg/steps of combustion. Besides, before the beginning of operation of the pump the engine should make from 40 to 75 full cycles, depending on OZh temperature. For the purpose of prevention of sudden jump of toxicity of OG at SAI system switching off, the pump SAI continues to work during 15 cycles of the engine after the termination of need for an air podmeshivaniye. At SAI system work for compensation of additional air the volume of injected fuel also increases.

For prevention of leakage of OG through SAI system in each block of cylinders the control valve which is closing at switching off of the pump SAI is established.

System of a retsirkulyatsiya of OG (EGR)

This system allows to reduce quantity _{of NO x} 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.