6.3. Systems of release and decrease in toxicity of the fulfilled gases
The system of production of the fulfilled gases of the petrol engine consists of a final collector, a reception pipe, the catalytic converter (leu), the central muffler, a connecting pipe, the additional muffler and an exhaust pipe (pipes). The system of production of the fulfilled gases of the 6-cylinder engine on the site between final collectors and the central muffler has two-line execution. Diesel engines are also equipped with two catalytic converters, first of which is located near the engine.
Within recovery repair each section can separately be replaced.
System of decrease in toxicity of the fulfilled gases
In power supply systems of all petrol models only unleaded gasoline has to be used. The control system of the engine functions so that to receive the maximum return from the engine at the minimum fuel consumption and toxicity of the fulfilled gases. The system of catching of vapors of fuel prevents hit them from the fuel tank in the atmosphere. The system of recirculation of the fulfilled gases is installed.
System of 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).
Decrease in toxicity of the fulfilled gases
For decrease in number of harmful emissions in the atmosphere on all petrol models the three-functional catalytic converter is built in system of release. The control system of injection of fuel has feedback which switched on the oxygen sensor. This sensor installed in system of release constantly informs the control unit on composition of the fulfilled gases. 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 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 gases. Depending on concentration of oxygen, the sensor sends signals of different tension. If mix of a pereobogashchen - the content of oxygen in the fulfilled gases very low, the sensor 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 the fulfilled gases there is a jump in tension on the sensor. This jump is a reference point for the control unit at correction of quality of mix.
Two sensors are installed: one - before, and the second - after assembly of the catalytic converter. It reaches more exact tracking of composition of the fulfilled gases.
System of recirculation of the fulfilled gases (EGR), - the models equipped with engines of series 112 and 113
The system of recirculation of the fulfilled gases allows to reduce the number of NOX in the fulfilled gases. For this purpose a small part of the fulfilled gases moves in the inlet pipeline via the special valve. The valve of system of recirculation is run by the control unit.
System of catching of vapors of fuel (EVAP)
For decrease in emission in the atmosphere of not burned down hydrocarbons on all petrol models the system of catching of fuel is installed. The filling 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 are stored there until on a signal of the control unit the filter purge does not begin. Then vapors of fuel begin to move via the purge valve(s) in the inlet pipeline, there 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.
The control system of the engine functions so that to receive the maximum return from the engine at the minimum fuel consumption and toxicity of the fulfilled gases. For additional decrease in toxicity of gases on the car several additional systems are installed. The system of ventilation of a case reduces leak of gases in the atmosphere from the engine lubrication system. The catalytic converter reduces toxicity of the fulfilled gases. The system of recirculation of the fulfilled gases is installed.
System of continuous ventilation of a case (PCV)
For elimination of leak of not burned down hydrocarbons in the atmosphere the engine is completely sealed. Gases and the oil evaporations which are formed in an engine case are passed via the mesh filter, go to the inlet pipeline and are burned in cylinders in the course of normal functioning of the engine
Removal of crankcase gases is carried out at the expense of a difference of pressure in a case and the inlet pipeline.
For decrease in number of harmful emissions in the atmosphere on all diesel models the catalytic converter is built in system of release. It neutralizes the most part of the gaseous hydrocarbons, monoxide of carbon (SO) and other toxic impurity which are contained in products of combustion of air-fuel mix.
System of recirculation of the fulfilled gases (EGR)
On all diesel models the system of recirculation of the fulfilled gases which main objective is decrease in percentage in products of combustion of the engine of nitrogen oxides (NOX) is also installed. For the purpose of performance of an objective a small part of the fulfilled gases from a path of system of release via the special valve is redirected the inlet pipeline. Functioning of the EGR valve is controlled by the control unit.