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What is the catalyst?

We buy spent automobile catalysts in any quantity by the best prices. For regular customers we have special pricing solutions.

What is a catalyst?

The catalyst – an element of car exhaust system, which is designed for afterburning of exhaust mixture till its ecologically clean condition. The catalyst is located either on the receiving tube, or soon thereafter. Inside of the catalytic converter’s carcass the is a ceramic honeycomb. Honeycombs are needed in order to increase the contact area of exhaust gases with the surface to which is applied a thin layer of platinumirridial alloy. Unburned residues (CO, CH, NO) touching with the surface of the catalytic layer, are oxidized to the end by the oxygen, which also exists as well in the exhaust gases. Inresult of the reaction releases heat, that warms up the catalyst and, thus, activates the oxidation reaction. In the end, leaving the (serviceable) catalyst, exhaust gases have a concentration of CO2. This concentration corresponds to EU rules!

About catalysts

Already now catalysts are a mandatory option for all modern cars. Catalysts (catalytic converters) are used for cleaning exhaust gases by oxidizing harmful compounds. The high cost of catalysts is due to the use of platinum, rhodium or palladium salts in them.

The internal structure of the catalyst can be made of ceramic or to be of metal. Ceramic catalysts are cheaper and that’s why are more common. But you have to pay for the economy. The ceramic catalyst is quite fragile and afraid of mechanical influences. For example from the impact of a stone lying on the road, inside honeycomb ceramics can fly into small pieces. The same thing can happen if during the movement into a red-hot catalyst will permeate water from a deep puddle. Also to destroy the ceramic catalyst may the malfunction of engine’s ignition system. This occurs due to the fact that during the abortive start of the engine, unborn fuel accumulates in the exhaust tract. When the car finally starts, in the catalyst happens an explosion and ceramic honeycombs can not stand and fall apart. Metal catalyst in this respect is more reliable.

But whatever would be the internal structure of catalysts, all of them quite quickly fail due to following reasons:

• Leaded or simply bad-quality petrol.
• Various “left” flushing of the fuel system.
• Oil or coolant permeates into the combustion chamber and accordingly into the catalyst.
• Supersaturated fuel mixture caused by malfunctions in the engine’s supply.

As a result, the catalyst loses its ability to perform its functions, that means to burn contaminants. In addition, there happens a decrease of the total cross-section due to clogging of channels. The car loses its power and begins to “blunt”. The catalyst becomes overheated; its carcass can be heated to red color, and even to set fire to the corrosion protection of carcass. Inside a faulty catalyst temperature may become so high that ceramics becomes melted and completely closes the outlet for exhaust gases. Naturally, that makes nothing good for engine.

One another disadvantage of the aging catalyst is a ceramic dust. Over time, despite the apparent integrity, ceramic block becomes gradually destroyed, and small pieces of ceramics enter into the combustion chamber. That causes increased depreciation of cylinder walls and of valve stem o-rings. That’s why why the replacement of the catalyst is recommended after every 100 000 km regardless of its performance.

Most often, the catalyst is fixed immediately behind the reception pipe before the main silencer and it is a separate easily removable part. This is the best option in terms of maintainability. However, there are catalysts, which are located directly in the exhaust manifold. This arrangement makes easier to implement environmental regulations, because this way the heating of the catalyst until operating temperature goes much faster. The disadvantage is the complexity of its replacement’s works, and potential possibility of collector’s damaging in the case of a faulty catalyst.