There is a vent pipe from the engine crankcase to the throttle valve. When the engine is hot, the oil evaporates, and the oil and gas enter the throttle through the vent pipe. The evaporated oil will be discharged through the air duct into the throttle valve to re-participate in the combustion. Part of the oil and gas will condense on the throttle, causing carbon deposits.

In addition, the cleaning principle of throttle carbon deposits is that this is a maintenance item rather than a maintenance item. If the engine has no idling jitter and other faults, there is no need to clean it. Do not clean the throttle frequently, otherwise it will damage the special coating on the inner wall of the throttle, causing more and more serious carbon deposits on the throttle, and it will also cause the throttle shaft to jam, and eventually cause damage to the throttle.

Because the throttle is completely closed at idle. Therefore, there is a bypass pipe next to the throttle valve to provide engine intake at idle speed. The idle speed motor controls the air intake of the engine in the idle state by adjusting the air flow of this bypass pipe, thereby controlling the idle speed.

There is also a part of the carbon deposits will run into the engine's intake system, such as the throttle, valve top, etc. Many car owners may question, isn't the combustion chamber in a closed state when the engine is doing work, and why is there still carbon deposits running into the intake duct?

The carbon deposits on the intake valve are also deposited by the residual fuel vapor and engine oil vapor in the intake pipe. The temperature in this part is relatively high, and the carbon deposits formed are relatively strong and stubborn, and the carbon deposits in individual models are serious. For engines that use manifold injection, due to the cleaning effect of fuel, there are few serious carbon deposits on the intake valve; for direct injection engines, there is no fuel cleaning at the intake valve, and most of them will have carbon deposits on the intake valve. The degree is different. Therefore, some models now use dual injection, manifold injection at low speeds, and direct injection at high speeds, which can effectively deposit carbon and avoid its deposition.

When a car is driving, the throttle will produce carbon deposits. If the throttle is too dirty, it will affect the normal intake of the engine, which will cause the engine power to be insufficient, and the compressor may be used or unwilling to drive the compressor.

During the engine process, the combustible valve enters the combustion chamber. At this time, a small part of the gasoline will adhere to the intake valve. When encountering the high temperature of the combustion chamber, the hydrocarbons, paraffin, and paraffin in the gasoline that cannot be completely burned The gum will be burned into gum carbon, which is the carbon deposit of the engine. As long as it is an internal combustion engine, carbon deposits cannot be avoided.

Eventually, the engine has abnormal phenomena such as difficulty in starting, unstable idle speed, poor acceleration, excessive exhaust gas, and increased fuel consumption. If it is more serious, it will cause the valve to be loosely sealed, making a certain cylinder completely because there is no cylinder pressure, or even sticking the valve to cause the valve to fail to return, and eventually damage the engine.

The longer the idling time, the longer the time for the engine to reach normal temperature, the slower the gasoline evaporates after being sprayed to the back of the valve, and carbon deposits are also generated. At the same time, often idling, the air flow into the engine is also small, so the scouring effect on carbon deposits becomes very weak, which will promote the deposition of carbon deposits.