Combustion is to blame, or if we’re talking about exhaust smoke, it’s more likely that it’s not combustion, but non-combustion. When the combustion process fails, hydrocarbons are formed. At high temperatures, it turns into soot. So into a black and very fine powder, which is shot out of the tailpipe in a slender ion with the exhaust gases. Not all of it, of course. Some of it settles in the exhaust system and eventually causes major problems for the system and the engine.
Why the combustion mixture doesn't burn?
As we can guess, the combustion mixture in a diesel engine is made up of two very important components – diesel fuel and oxygen, in other words, air. The engine control unit software determines perfectly how much of each component should be present to get maximum efficiency.
Unfortunately, the technical condition of our engines is not always perfect and various side effects can change these proportions. The reasons can be many and varied, so the easiest way to find the fault is with the help of a computer.
In any case, either too little oxygen or too much diesel is entering the combustion chamber. In both situations, the combustion mixture is not used up to the last drop, forming the soot mentioned above.
Is the engine always to blame?
Often it’s not the engine or the control unit that’s at fault. Poor quality fuel is a big “disservice”. Either it’s just a poor choiace of fuel vendor, or it’s our efforts to save money by using a less-than-legal way of buying diesel. In such situations, however, the black smoke of the exhaust system should end if the car is supplied with a quality power source. If not immediately, at least after a few dozen kilometers.
The most common engine problems could be piston wear or mechanical failure, air or fuel intake or the so-called EGR valve. It should come as no surprise that black smoke from the exhaust system is accompanied by a noticeable increase in fuel consumption, loss of power and problems starting the engine when it is warm.
Does black smoke from the tailpipe immediately mean there's a problem?
For some diesel engines, this is normal under light loads, such as sudden acceleration. However, if we happen to see black smoke behind our cars often, it could already mean that there is a problem with the fuel injection system. It could be the result of poor fuel quality or worn injectors. If you are more fortunate, then simply replacing the pipes at the intercooler will suffice. This applies to situations where the car is losing power and the engine is too noisy.
If you are the owner of a relatively new vehicle, you should start worrying about black smoke. As far as we know, old diesels are notorious for “smoking” and in this case it does not mean that there is a problem with the engine. In petrol engines, black smoke is often the result of poor tuning.
Of course, every problem has its solution, which is best sought either from your trusted technician or from a garage specializing in diesel engine repairs like A1 Diesel in Accra.