The exhaust system is an integral part of every car. Over the years, it will be improved, and now almost all cars are equipped with a catalyst. What is this element and how to determine that a catalyst is clogged? Symptoms and element design are described later in our article.
Appointment
The full name of the element is a catalytic converter. It serves to reduce the level of emissions of harmful substances into the atmosphere that get there with exhaust gases.
Where is it used?
This element is used on all diesel and gasoline engines with Euro-3 standards and above. The catalytic converter is installed immediately after the exhaust pipe - behind the exhaust manifold.
Device
An element consists of several parts. This is a housing, a carrier block and thermal insulation. The second is the main element in this “chain”. The block is made of special ceramics, which is not afraid of high temperatures. By design, this part is a multitude of cells.
They significantly increase the contact area of ​​the ceramic "core" with exhaust gases. On the surface of these cells there are special substances (catalysts). These are palladium, platinum and rhodium. These elements accelerate the time of chemical reactions. Palladium and platinum belong to a number of oxidizing catalysts. Thanks to them, hydrocarbons contained in gases are converted into water vapor; carbon monoxide oxides - into carbon dioxide. Rhodium is a reducing element. It turns nitric oxide into harmless nitrogen. Together, all three chemical elements reduce the level of harmful substances in the exhaust gases.
Structurally, the carrier block is located in a metal case. Between these two elements is a layer of thermal insulation. An oxygen sensor is also located inside the converter . The main condition for the operation of the catalytic converter is the high temperature of the gases (about 300 degrees). When heated to this level, rhodium, palladium and platinum can hold up to 90 percent of the harmful substances that would enter the atmosphere.
How to identify a malfunction?
What are the signs of a clogged catalyst? There are several symptoms due to which you can find out the malfunction of this element:
- The car has become difficult to start.
- There are dips during movement, which sometimes disappear.
- The “Check engine” light is on.
The reasons for the poor acceleration dynamics are explained by the low catalyst throughput.
Sometimes it happens that a car easily picks up speed of 150 km / h and then, having stopped, barely accelerates to 60. As a result, the performance of the motor decreases sharply (low level of cylinder ventilation). The engine is not able to capture a new portion of air, since the exhaust gases cannot exit the system normally - they “get stuck” in the combustion chamber.
Why is this happening?
If you have a clogged catalyst, the signs (whether it is diesel or gasoline - it does not matter) of its malfunction may be a high smoke content of the gases. They contain a certain percentage of oil (this is natural), but when the engine “eats” a liter for a thousand kilometers, it begins to remain on the cells of the converter. Also, signs of a clogged catalyst are the small diameter of the flow cells. Due to the high concentration of resins and impurities in the fuel, they are easily clogged in this element.
Note that poor fuel quality plays an important role in the catalyst resource. With frequent use, bad fuel settles in the exhaust manifold, before it has completely burned out in the chamber. This can cause overheating of parts of the catalyst. An important role is played by mechanical damage. The slightest blow about unevenness (the same speed bump ) will cause deformation of the element, because of which it will not function normally. The small crumbs, which broke off in the catalyst cavity, easily clogs the small cells. Thus, the main signs of a clogged catalyst (VAZ-2172 is no exception) are associated with the inability of the system to normally “exhaust” exhaust gases, which is why they stagnate in the exhaust pipe and cylinders. This provokes a large loss of power and increased fuel consumption.
What to do if the catalyst is clogged? Signs and diagnostics of the item with your own hands
There are three ways to check it. The first is the most effective.
This is a test of the catalyst during dismantling. It is attached very simply. For dismantling it is necessary to take two ring spanners or open-end wrenches at 13. We fix the bolt on one side and rotate the nut counterclockwise on the other. However, difficulties may arise. Since the converter is located under the bottom (not the cleanest place in the car), its fasteners can simply rust.
And the standard WD 40 does not save here. Therefore, in half the cases, you have to pick up a grinder and cut off the bolts. But that's not all. Since the converter is part of the exhaust system, it operates at elevated temperatures. Accordingly, its parts (one goes from the receiving pipe, the second to the resonator) simply sticks to the neighboring metal. In this case, only hammer blows are saved. But this is not the best solution. As we said earlier, from the smallest blows the inside is easily deformed. Cutting the remaining elements to remove the catalyst with a grinder is also not an option. Therefore, it turns out that removing this element out is not so simple. Well, if the catalyst is not stuck, when it is successfully dismantled, carefully inspect it for clogging - there should be a through gap between the grids.
Second way
This diagnostic method is performed without mechanical intervention - the catalyst remains in its rightful place. The method involves measuring the pressure in the system. To do this, a manometer is screwed into the place of the oxygen sensor (sometimes an adapter is required) and readings are measured at different engine speeds.
At 2.5 thousand, the normal level is 0.3 kgf / cm 3 . If the value is less than permissible, the gases are not able to normally go outside. Because of this, the car loses in power. Diagnostics can also be performed using a motor tester (the most technologically advanced method today). A pressure sensor is screwed into the cylinder in place of the candle. Then, at different revolutions of the crankshaft, an analysis of the waveform is performed. Naturally, all this requires the availability of equipment, so the first method is more familiar to our car owners.
Delete item
If you have a clogged catalyst (we examined the signs of a malfunction), it must be replaced with a new one.
However, there is a problem - the average cost of new converters is about $ 100. Therefore, motorists simply remove it from the system, installing a flame arrester or a spacer in the form of an ordinary pipe in its place. However, after such actions, the catalyst is necessarily removed from the ECU unit (car brains). It is believed that this action will increase the power and throttle response of the machine by 5 percent (due to better exhaust ventilation).
So, we examined why the catalyst is clogged, signs of a malfunction, and ways to solve it.