Symptoms of carbon deposition in engine parts Symptoms of carbon deposition in engine

The formation of carbon deposit is directly related to automobile fuel and lubricating oil. Gasoline itself contains colloid and impurities, which will bring in dust and impurities during storage and transportation. When gasoline molecules that do not participate in combustion adhere to the air intake, intake valve and combustion chamber wall, wax and colloid are left after evaporation and oxidation, and some soft black carbon deposits will be produced in the intake pipe, especially behind the throttle.

In the combustion chamber, due to the lack of oxygen during combustion, the fuel and lubricating oil escaping from the combustion chamber can not be completely burned, resulting in soot and charred lubricating oil particles, which form hard cemented carbon under high temperature and oxidation, commonly known as carbon deposition. The components of carbon deposit include volatile substances (oil, basic acid) and nonvolatile substances (asphaltene, oil coke, carbonitride and ash, etc.). ).). The more non-volatile substances, the harder and tighter the carbon deposit, and the stronger the bond with metal.

Symptoms of excessive carbon deposition in the engine

If the engine burns engine oil, the crankcase is ventilated with engine oil, or the quality of gasoline is poor and there are many impurities, then the carbon deposition will be more serious and the formation speed will be faster. These carbon deposits will make the intake pipe wall rough, and the intake air will produce eddy currents in these rough places, which will affect the intake effect and the quality of the mixture. On the other hand, these carbon deposits may also change the size of the throttle passage, block the idle passage, and make the idle speed control device stuck or out of its adjustment range, resulting in unstable idle speed or even flameout, excessive emissions and increased fuel consumption.

Wax and gum attached to the intake valve and combustion chamber wall will be heated repeatedly when the engine is working, and the carbon deposit in this part will become harder. Because the internal structure of carbon deposit is similar to sponge, when carbon deposit is formed in the valve, a part of the fuel injected into the cylinder will be adsorbed every time, which will dilute the concentration of the mixture that really enters the cylinder, resulting in abnormal phenomena such as poor engine operation, difficult start-up, unstable idle speed, poor acceleration, too fast refueling and tempering, excessive emissions and increased fuel consumption.

Symptoms of excessive carbon deposition in engine parts

(1) The piston ring is attached to the cylinder wall, which affects the cylinder seal and reduces the power;

(2) aggravate the wear of the cylinder wall;

(3) The piston ring groove sticks to the piston ring;

(4) The piston ring has abnormal sound when working.

(5) Carbon deposition on the valve and valve seat will lead to poor matching between the valve and valve seat and affect the sealing performance of the cylinder.

(6) Carbon deposition on the valve stem will cause the valve to be stuck, unable to open and close normally and unable to work.

(7) The carbon deposit in the spark plug will form a hot spot, which will lead to early ignition, and it will also cause leakage in the primary circuit of the ignition coil, which will lead to weak spark and even insufficient ignition.

(8) Carbon deposition in the injector will cause needle valve blockage or nozzle blockage, resulting in abnormal fuel injection and abnormal engine combustion.

(9) Carbon deposition in the cylinder will reduce the combustion chamber volume and increase the compression ratio, which is easy to cause detonation combustion.

(10) Carbon deposit is a poor conductor of heat, which leads to poor heat dissipation conditions of pistons, piston rings and valves. Cause the engine to overheat and not burn normally, thus accelerating the wear of parts.

(1 1) The hardness of carbon deposit is relatively high, which will cause motion interference between the valve and the piston in severe cases, and the impact will produce knocking sound.