What is the black stain on the exhaust pipe of the car?

There is black ash in the automobile exhaust pipe, which belongs to carbon deposition. The reason is that the exhaust pipe of a car burning engine oil must be black, but a car with a black exhaust pipe does not necessarily burn engine oil.

The black carbon of automobile exhaust pipe is serious. Although it is not a mistake, one thing is certain. The air-fuel ratio of the engine may often go wrong, that is, the gasoline engine is usually not enough and there is too much carbon deposit.

In addition, after incomplete combustion of oil and gas, after three times of catalysis and partial carbonization, these carbon ashes will accumulate in the exhaust port over time, resulting in more than 80% of the exhaust pipe of supercharged engine blackening.

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Compared with ordinary turbine models, the blackening of exhaust pipe of direct injection turbocharged engine is more serious. It can be said that most of them can't escape the fate of blackening the exhaust pipe. The new exhaust pipe, even if it is new, will soon turn black.

Direct-injection engines inject gasoline directly into cylinders through fuel nozzles instead of supplying fuel in the form of steam. Using direct injection technology, fuel enters the cylinder in the form of fine droplets.

Due to the special structure of direct injection engine, the "self-cleaning" ability of carbon deposit in the back area of intake valve is much weaker than that of ordinary EFI engine. Therefore, although the direct injection engine has obvious fuel-saving advantages, carbon deposition is also a thorny problem that we have to face, especially on the back of the intake valve.

Phoenix. Com- the exhaust pipe is black. Is there anything wrong with the car?