What maintenance projects should Volkswagen LaVida do for 60,000 kilometers?
Carbon deposition includes two concepts: one concept is engine carbon deposition: a combustion substance produced by unsaturated olefins and gums in fuel at high temperature during engine operation. The second concept is carbon deposition in EDM, which should be avoided as much as possible, especially in precision die machining.
Carbon deposition is a manifestation of abnormal discharge machining of spark machine. It can be clearly seen from the sketch of a general engine that the power source → mixed gas must enter the combustion chamber through the intake valve; A small amount of gasoline will adhere to the intake valve. When the engine is at a high temperature, hydrocarbons, paraffin and colloid that cannot be completely burned in gasoline will burn into colloidal carbon. If there is scale in the nozzle, the sprayed gasoline will be in a state of poor atomization, and the uneven mixing of gasoline and air will increase the condensation of gasoline in the intake valve.
The power of the engine comes from the fact that when the piston of the engine moves downward, the mixture of gasoline and air is sucked into the cylinder, and then the upward piston compresses the oil and gas into highly combustible gas, and finally the spark plug ignites it. The piston is pushed by this powerful explosive force, so the engine generates power. The gas source of power mixture must enter the combustion chamber through the intake valve; A small amount of gasoline will adhere to the intake valve. When the engine is at a high temperature, hydrocarbons, paraffin and colloid that cannot be completely burned in gasoline will burn into colloidal carbon. If there is scale in the nozzle, the sprayed gasoline will be in a state of poor atomization, and the uneven mixing of gasoline and air will increase the condensation of gasoline in the intake valve. Unfortunately, rubber carbon has the characteristics of absorbing gasoline, so this layer of carbon will absorb gasoline, and the absorbed gasoline will be burned into rubber carbon to form thicker carbon, and the thicker carbon will absorb more gasoline, and so on, until there is too much carbon to close the intake valve and make the engine unable to run.
Carbon deposition in the combustion chamber is due to tiny carbon particles produced by colloid in gasoline and hydrocarbons that cannot be completely detonated after explosion, and does not accumulate in the combustion chamber with exhaust gas. These black particles should be discharged into the atmosphere with the exhaust gas or accumulated on the muffler pipe. If the carbon deposition in the combustion chamber is serious, the temperature of the combustion chamber will rise, which will lead to the ignition of the spark plug and the self-explosion of the combustion chamber mixture. The two deflagration points make the cylinder pressure suddenly rise, damage the internal and external parts of the engine, and make a sound similar to knocking on the cylinder block. This is knocking. By observing the ignition end of the spark plug, we can know the carbon deposition in the combustion chamber.