6.2. Systems of release and decrease in toxicity of the fulfilled gases
System of release of OG
The system of production of the fulfilled gases consists of final collectors, reception pipes, catalytic converters, mufflers and an exhaust pipe.
Systems of decrease in toxicity of the fulfilled gases
Components of systems of decrease in toxicity of OG
Scheme of work of systems of decrease in toxicity of OG
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) prevents hit of the last of the fuel tank in the atmosphere. Also the system of ventilation of a case (PCV) is installed.
System of the operated ventilation of a case (PCV)
For elimination of leak of not burned down hydrocarbons in the atmosphere the engine is completely sealed. The gases and vapors of oil which are formed in a case via the mesh filter get to the inlet pipeline and burn down in cylinders together with fuel.
Gases are removed from a case at the expense of 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 the fuel tank is hermetically closed by a cover, under the fuel tank the coal adsorber is established. In it the fuel vapors which are formed in a tank during the parking of the car gather and keep there until on a signal of the control unit the adsorber purge does not begin. During a purge of couple of fuel move via the purge valve in the inlet pipeline where they mix up with 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 closed. Thus hit of not burned down fuel in the converter (is prevented at the raised idling turns mix of a pereobogashchen). After warming up of the engine the valve begins to open and be closed, giving fuel vapors to an inlet path.
Catalytic converter and lambda probes
For decrease in number of harmful emissions in the atmosphere three-functional catalytic converters are built in system of release. The control system of injection of fuel has feedback which included a lambda probes, OG which are constantly informing the control unit on structure. Depending on the obtained data, the control unit corrects quality of the mix given to combustion chambers and, thus, optimizes fuel combustion.
In a lambda probe, established behind catalytic converters, the heating element which is switched on by the control unit via the special relay is built in. The working surface a lambda probe is sensitive to change of content of oxygen in OG. Depending on concentration of oxygen the output tension of the sensor changes. If mix of a pereobogashchen (content of oxygen in the fulfilled gases very low), the lambda probe gives signals with low voltage. Tension increases in process of impoverishment of mix and increase in 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 mix.
It is established three a lambda probe: on one in front of the top catalytic converters (these a lambda probes at the same time are sensors of quality of air-fuel mix) and one behind the lower converter. It reaches more exact tracking of structure of OG.