Which exhaust gases are measured at the roadworthiness test in Montenegro

Last year, Volkswagen's control of emissions of harmful gases from diesel generators was one of the main topics in the world media. Experts from the US Environmental Protection Agency found that cars in real conditions emit much higher amounts of nitrogen oxides (NOx) than is the case during testing in the laboratory. In addition to this compound, today the most harmful product of engine combustion is carbon dioxide. "Carbon dioxide is harmless in itself, but it has indirect effects because it largely contributes to the effect of creating a greenhouse in the atmosphere and thus contributes to global warming," says Radenko Damjanović, director of technical inspection stations "Sava car". "On the other hand, nitrogen oxides are responsible for photochemical smog, acid rain or liquid ozone in the lower atmosphere."

If you have wondered how much your car emits these gases, you will not be able to find the answer even during the technical inspection of the vehicle.

"Neither compound is a condition for confirmation of correctness at the technical inspection in Montenegro. In our country, optional devices can measure nitrogen oxides, but this is not done in our country according to the official legal regulations", says Damjanović.

If your vehicle consumes diesel fuel, you will only be sent back for repairs if too much soot comes out of the exhaust, or simply, if it smokes too much.

"A device called an opacimeter directly measures the attenuation of the intensity of the light beam that was previously passed through the exhaust gas being tested. This attenuation of the light beam is directly proportional to the content of soot, which has the ability to absorb that light," explains Damjanović.

According to the regulations, the maximum smoke coefficient for older engines is up to 3, for turbo engines up to 2,5, and for Euro 4 aggregates and newer, this limit is up to 1,5.

On the other hand, gases from gasoline engines have a higher content of carbon monoxide and carbon hydrogen than diesel engines.

In the case of gasoline engines, the control is carried out through exhaust gas analyzers, which measure the content of four exhaust gases - carbon monoxide, carbon dioxide, oxygen and hydrogen chloride. However, you will not pass the roadworthiness test only if there is an excessive amount of carbon monoxide. Everything else is measured for statistical purposes only.

"Carbon monoxide is really a direct danger. It is a colorless and odorless, poisonous gas, it reduces the ability to carry oxygen in the blood. Small amounts can lead to loss of consciousness, poisoning, and soon death. Therefore, any vehicle with a concentration of of carbon monoxide exceeds the prescribed limits, it is automatically qualified as technically defective and goes for servicing," says Damjanović.

Limit values ​​of carbon monoxide in vehicles without a lambda probe, when the engine is idling, are up to 4,5% of the total volume for vehicles that were first registered before October 1, 1986, i.e. up to a maximum of 3,5% for those that registered for the first time after that.

When it comes to newer vehicles, which have a three-component catalyst, the limits are much stricter and amount to 0,5% of the gas volume when the engine is idling, or 0,3% of the maximum volume at 2.000 revolutions.