[Oxcart Laboratory Science] Driving acceleration is weak. Don't be cheated. The carbon canister may be the source of the fault.

If you find that the vehicle is getting tired, accelerating slowly, and sometimes getting stuck, go to the garage to have a check, which mostly means that your engine has carbon deposits, clean the throttle, clean the inside of the engine and change the spark plug. It costs you a lot of money anyway, and it may not solve the problem in the end. Don't repair this situation first, you can make a preliminary judgment. It may be the fault caused by the carbon canister.

What is a carbon canister? Baidu Encyclopedia explained that carbon tanks are generally installed between the gasoline tank and the engine. Because gasoline is a volatile liquid, the fuel tank is often filled with steam at room temperature. The function of fuel evaporative emission control system is to introduce steam into combustion and prevent it from evaporating into the atmosphere. The storage device of activated carbon tank plays an important role in this process.

Because of the adsorption function of activated carbon, when the car is running or turning off, gasoline vapor in the fuel tank enters the upper part of the activated carbon tank through the pipeline, and fresh air enters the activated carbon tank from the lower part. ? After the engine is turned off, gasoline vapor and fresh air are mixed in the fuel tank and stored in the activated carbon fuel tank. When the engine is started, the electromagnetic valve of the fuel evaporation purification device installed between the activated carbon canister and the intake manifold is opened, and the gasoline vapor in the activated carbon canister is sucked into the intake manifold to participate in combustion.

Gasoline is a volatile fuel, and the fuel in the fuel tank volatilizes quickly, which will increase the pressure in the fuel tank. When the pressure reaches a certain value, there will be danger, so people try to balance the pressure. At first, the fuel tank cover was made into a pressure-limiting valve. When the pressure was higher than a certain value, the pressure-limiting valve opened and the gasoline vapor was discharged into the atmosphere. Later, from the perspective of saving fuel and protecting the environment, people set up carbon tanks, which were filled with activated carbon with strong adsorption. Activated carbon absorbs fuel vapor. When the car starts, the solenoid valve of the activated carbon tank is opened in time to pour the absorbed fuel vapor back into the intake manifold, which is fuel-efficient and environmentally friendly.

Knowing what a carbon canister is and its working principle and function, we can analyze whether some faults are related to the carbon canister. For example: A, the car coughed when giving oil; B, some cars with a long history smelled of gasoline; D, when accelerating, they felt weak; the engine idling was unstable, which was probably the cause of the carbon canister.

A. If the car "coughs" when accelerating, that is, the car is damaged or the carbon tank pipeline is damaged, you can check it carefully. Gasoline vapor will be discharged from the damaged place, so some classic cars may be damaged due to aging pipes, which will eventually cause the smell of gasoline in the car. This is also the explanation of case B. Damage to the pipes of carbon tanks may also cause air to directly enter the engine intake, dilute the engine mixture and make the car "cough".

C, D, if the car is idling at high and low speed after starting, you can check whether there are dirty things in the air inlet and filter screen of the carbon tank. If the filter screen is too dirty, fresh air is not easy to enter the carbon canister. When idling, the gasoline vapor in the carbon canister is sucked into the intake manifold due to vacuum suction. When the oxygen sensor detects that the mixture concentration is high, the engine will reduce fuel injection, then the mixture concentration will become smaller, and finally lead to low idle speed. Then the oxygen sensor detects that the mixture is too thin, the fuel injection increases and the idle speed becomes higher. This leads to the rise and fall of idle speed.

On the other hand, if the car can't hit the car, you can also check the carbon canister, and the solenoid valve of the carbon canister may cause problems. If the solenoid valve is always closed, there will be more and more gasoline vapor. After the carbon tank is full, no amount of gasoline vapor can be discharged outside the car. If the solenoid valve is always on, the air-fuel mixture at the air inlet will always be rich, and then the air-fuel mixture will be too rich when the hot car is turned off, or it will be difficult to start after the hot car is turned off.

The above picture shows the chassis structure of Geely Yue Bin, and the carbon tank is located near the fuel tank. This design is a general scheme for most models, which is relatively safe and secure. The following lists the positions of several alternative carbon tanks, which may have certain hidden dangers from the safety point of view.

The picture above shows Sylphy: We found a gasoline tank at the rear of the car, which should be located near the fuel tank, but it appears here, which is a bit puzzling. The corner of the tail is obviously a high-risk area for collisions and rear-end collisions. Although it won't cause any serious consequences, the gasoline vapor will leak when it collides here, which may lead to the change of fuel tank pressure and the vehicle can't run normally.

The picture above shows the location of the carbon canister of BMW's new 3 Series. BMW has always designed the carbon canister at the bottom of the rear of the car, which is further outside than Sylphy's position. Probably because of the use of a larger carbon canister, there is no room for the chassis. However, the provisions of relevant laws and regulations on carbon tanks are limited to meeting environmental protection standards, and there is no requirement for their location.

The engine compartment layout of Baojun 5 10 is reasonable and remarkable. The harness is well protected, and there is a large heat dissipation space in the engine compartment. However, inadvertently, we found another strange thing, that is, near the firewall, there is a black box-carbon canister! ! ! Why is this? The gasoline steam carbon canister is generally under the chassis and next to the fuel tank. There are some safety hazards in the engine compartment. Once the gasoline vapor leaks, it may cause a fire, and the carbon canister is too far away from the fuel tank, which will weaken the performance of vapor recovery.

Summary: Carbon canister, an essential environmental protection device for every car, may not be known to everyone, but when it breaks down, it will often cause a series of engine problems, which will often mislead inexperienced maintenance technicians, or be used by unscrupulous black shops to deceive customers and make car owners spend more on maintenance. You might as well learn some simple and memorable knowledge of automobile technology, which may be used one day.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.