6.4.1. Catalytic converter
All Corsa and Tigra cars with petrol and diesel engines are serially equipped with catalytic converters for purification of the fulfilled engine gases.
The catalytic converter has the central ceramic part of a cellular design covered with a layer of salts of the precious metals operating as the converter. The catalytic converter is fixed in the case by means of the insulating basic layer compensating at the same time thermal expansions of the catalytic converter.
The EFI system in combination with a lambda probe carry out exact regulation of amount of injectable fuel that the catalytic converter could reduce amount of harmful substances in the fulfilled gases. The lambda probe is in a reception pipe in front of the catalytic converter and is washed by a stream of the fulfilled gases. The lambda probe represents an electric measuring element which defines concentration of oxygen in the fulfilled gases by means of change of tension and allows to correct quality of air-fuel mix, thus. During a fraction of a second the lambda probe can transmit the corresponding signals to ECM that allows to correct continuously quality of air-fuel mix depending on change of service conditions (idling, full gas). Thus optimum reburning of fuel in the catalytic converter is reached.
That in the catalytic converter at a temperature of 300 ÷ the 800th hail. there could be a fuel reburning, air-fuel mix has to be grown slightly poor by air.
On petrol engines the three-component catalytic converter allowing to reduce the content in the fulfilled gases of monoxide of carbon (SO), hydrocarbon (NANOSECOND), and also nitrogen oxides (NO x) is used.
On diesel engines the oxidizing catalytic converter since oxygen regulation is not required is used. Such catalytic converter reduces concentration of carbon monoxide and hydrocarbon, the fulfilled gases which are contained in. Besides, it reduces a smell, characteristic of diesel engines, of the fulfilled gases.
Catalytic converter and EGR system
Concentration of nitrogen oxides (NO x) in the fulfilled gases of engines 1.0 and 1.2 of l, and also l DOHC 1.4 and 1.6 from 09.1994 g of release are maintained at a low level to the catalytic converter thanks to existence of the EGR system.
The EGR system valve on DOHC 1.0 and 1.2 engines of l is on the face party of a head of cylinders; on other engines it is on a final collector and ECM copes. The task of EGR consists in withdrawal of a part of the fulfilled gases in engine combustion chambers for the purpose of decrease in temperature of combustion and, thereby, decrease in concentration of harmful substances.
Purification of the fulfilled gases by means of supply of additional air
Problem of supply of additional air in l DOHC 1.4 and 1.6 engines from 09.1994 g of release yavlyaetsyasnizheny concentration of harmful substances in the fulfilled engine gases at warming up of the engine. The electric pump gives fresh air to final canals of the engine to provide reburning of not burned down connections in the fulfilled gases. Thanks to it concentration of harmful hydrocarbons and carbon monoxide is reduced. Besides, temperature of the fulfilled gases increases thanks to what the catalytic converter gets warm quicker and oxygen regulation begins to work. ECM turns off supply of additional air with activation of oxygen regulation approximately in 1 ÷ 2 min. after cold start.
Security measures at operation of the cars equipped with the catalytic converter
Lambda probe and the catalytic converter it is necessary for an exception of damages surely follow the following recommendations:
Use only unleaded gasoline. During wrong filling with ethylated gasoline it is necessary to replace the catalytic converter and a reception pipe before it. Before installation of new elements it is necessary to spend, at least, two fillings of the fuel tank with unleaded gasoline.
Pushing or towage it is better to exclude start of the heated-up petrol engine. For this purpose use the auxiliary accumulator. Not burned down fuel at ignition can lead to an overheat and destruction of the catalytic converter.
Exclude the frequent following one after another cold starts. Otherwise in the catalytic converter not burned down fuel which when heating burns down collects and, detonating, damages the catalytic converter.
At difficulties in start of the engine it is not necessary to include for a long time a starter since at the same time the continuous injection of fuel is made. Establish and eliminate a cause of defect.
With malfunctions in ignition for identification of a source of malfunction exclude injection of fuel during inclusion of a starter. For this purpose switch-off the relay of the fuel pump located in a foot well of the forward passenger before resistant A, behind a side slip.
Do not check a spark plug for a spark at their disconnected socket.
Do not disconnect ignition from any cylinder since at the same time not burned down fuel gets to the catalytic converter.
At emergence of interruptions in ignition do not increase the speed of the engine and immediately eliminate malfunction.
Petrol and diesel engines
Do not put the car over a dry grass or foliage since the system of release warmed in the field of the catalytic converter can cause fire emergence.
You watch that the level of motive oil did not exceed the mark MAX in the probe of its measurement. Owing to incomplete combustion oil can get to the catalytic converter and cause its malfunction.