Why do cars have carbon deposits? What is the relationship between engines and carbon deposits?
Carbon deposition refers to hard cemented carbon, that is, carbon deposition, which is produced by colloid (mainly composed of hydroxy acids, asphaltenes, oil additives, etc.). ) When the fuel and lubricating oil entering the combustion chamber in series can't burn completely, and then stick to the intake/exhaust valve, cylinder edge, piston top, spark plug and combustion chamber) under the repeated high temperature of the engine.
Although today's engine technology has made great progress, the combustion chamber efficiency is only 25%-30%. Therefore, carbon deposition is mainly caused by poor quality of machinery itself and gasoline. The quality of gasoline produced by general refineries may be different, so the impact degree is slightly different. But if solvent oil or illegal oil is used, it will lead to more serious carbon deposition. After the car runs for a period of time, the fuel system will form certain deposits.
This car accelerates very slowly. Carbon deposition reduces the intake passage and inflation coefficient, which leads to the increase of cylinder pressure and the delay of ignition time, resulting in the decrease of engine power. The vehicle is difficult to start. Carbon deposits fall into the intake valve seat channel, which will cause insufficient cylinder pressure. In addition, the injected fuel is adsorbed by carbon deposits at the start, which leads to the lean mixture in the cylinder and the engine can not be started normally. Engine idle speed is unstable. When carbon deposits are attached to the intake valve and throttle valve, the engine cannot accurately control the amount of gasoline and air sent into the combustion chamber, resulting in unstable idle speed of the engine. ?
Fuel consumption has increased. When carbon deposits accumulate in the combustion chamber, it is easy to cause knocking, which delays the ignition time of the engine, reduces power and increases fuel consumption by 4~5%. ? Exhaust emissions exceed the standard. Carbon deposition leads to an imbalance in the mixing ratio of gasoline and air, which leads to insufficient combustion of gasoline, an increase in the contents of CO and HC in tail gas, and the emission is not up to standard. Engine trouble. When carbon deposits are attached to the intake valve stem, the valve stem and the guide pipe will be stuck, which will cause the piston to hit the valve and the engine to sound abnormally, thus causing damage to the intake valve and the piston.
The reduction of power will be accompanied by a certain increase in fuel consumption, because to obtain the same power as before carbon deposition, it is necessary to increase the throttle opening and increase the corresponding fuel supply. Therefore, when the fuel consumption increases for unknown reasons, it is necessary to check whether there is carbon deposition in the cylinder. Usually, the emission of pollutants in the exhaust gas will increase during the annual inspection of automobiles. At present, only carbon monoxide, hydrocarbons and nitrogen oxides are detected, and all three indexes can rise or exceed the standard when carbon is deposited, which may appear earlier than the decline of power and the increase of fuel consumption.
If you don't pay attention to oil products and driving habits for a long time, the wax and gum in gasoline will accumulate thicker and thicker, harden after repeated heating, and form carbon deposits. If the engine burns engine oil, or the quality of gasoline is poor and there are many impurities, the valve carbon deposit will be more serious and form faster.
Because the structure of carbon deposit is similar to sponge, when the valve forms carbon deposit, 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 poor engine operation, difficult starting, unstable idle speed, poor acceleration, sudden refueling and tempering, excessive displacement and increased fuel consumption. In severe cases, the valve does not close tightly, so that there is no cylinder pressure in the cylinder and it does not work at all, or even the valve does not return. At this time, the valve and piston will interfere with each other and eventually damage the engine.