6.6.1. Catalytic converter
Catalytic converter contains block carriers 3 (fig. 5.55) with a covering from active catalytic agent. Salts of precious metals on which surface there are chemical transformations are a part of this substance. Catalytic converter is fixed in the case 1 by means of an assembly pillow 2. As the pillow is the good insulator, there is no need of additional thermal insulation.
Just before catalytic converter the sensor of concentration of oxygen is located. It shows the residual content of oxygen in the fulfilled gases and sends the corresponding signal to the control unit of the engine, that in turn controls and changes composition of fuel-air mix (poor or rich). Optimum reburning in catalytic converter happens when the fulfilled gases contain enough fuel. Reburning temperature – 300–800 °C, at the same time fuel-air mix has to contain bigger amount of fuel.
Thanks to regulation of coefficient of excess of air in catalytic converter there is an oxidation of carbon monoxide (SO), hydrocarbons (SN) and reduction of nitrogen oxides (NOh).
For providing necessary service life of catalytic converter it is necessary to fulfill the requirements provided below.
Precautionary measures during the work with catalytic converter
Fill the fuel tank only with unleaded gasoline.
During the filling or a doliva of engine oil in the engine surely you watch that the level of oil did not rise above the maximum mark.
Do not allow launch of the engine which is warmed up up to the working temperature towage of the car. Not burned down fuel which got to catalytic converter can lead to its destruction.
At difficulties with launch of the engine you do not hold long a starter included as fuel at the same time is injected into cylinders and gets to system of release. Find and eliminate malfunction.
Do not allow a full expenditure of fuel in a tank.
At emergence of admissions of ignition do not increase turns of a bent shaft. Define and remove a cause of defect of system of ignition.
Apply only the spark plugs recommended for this car.
You carry out an inspection of sparking only at the removed safety lock of the fuel pump.
You do not carry out a comparative inspection of operation of cylinders by shutdown of ignition of one of them. It can lead to hit of not burned down fuel in catalytic converter.
Do not put the car after a trip on a dry grass or foliage. It can lead to fire emergence as in a zone of catalytic converter of a detail of system of release are warmed to high temperature.
You do not apply on details of system of release mastic against corrosion of the bottom of the car
Repair of system of production of the fulfilled gases
Through corrosion can be eliminated by means of welding, but only for a short time. Special hard putty or a bandage keep longer, but in this case corrosion will appear again, near places of repair. In systems of release with number of mufflers more than one quite often after replacement of one of mufflers of the second fails. Therefore, as a rule, the service centers change system entirely. And still, before you will begin to work with system of release, examine it and solve, it is necessary to replace separate parts or all system.
SEQUENCE OF WORKS
1. Lift the car and steadily fix on supports.
2. Remove the rusted threaded connections, for assembly use only new fixture, washers and laying.
3. Replace new all rubber details of a suspension bracket of system.
4. If earlier system details were already replaced, it is better to divide butt connections of pipes in a heated state. The service centers use for this purpose gas torches, the good household gas torch will also be suitable for this purpose. Protect hands gloves, eyes — points, prepare the fire extinguisher. Before applying a torch, try to use rust solvent.
5. Disconnect pipes strong rotary motions and easy blows of the hammer. If it did not help, cut off pipe connection of the defective muffler exactly on 10 cm behind a junction. You nadpilit the rest of a pipe a hacksaw on length and move apart the strong screw-driver;
For simplification of removal of system grease fastening details with copper LIQUI MOLI LM0-508-ASC paste.