1. canister
DEFINITIONS
before the canister is typically mounted fuel tank and the engine. Since fuel is a volatile liquid at room temperature are often filled the fuel tank vapor, action of the fuel evaporative emission control system the vapor is introduced into the combustion into the atmosphere and to prevent evaporation. This process plays an important role in the storage means is a charcoal canister.
Working Process
Since the activated carbon adsorption function, or turn off when the car is running, fuel vapor into the fuel tank through the upper portion of the charcoal canister conduit, fresh activated carbon from the air into the charcoal canister lower tank.
After the engine stall, gasoline vapor tank mixed with the fresh air and stored in the carbon canister, after the engine starts, fuel is mounted between the charcoal canister and the intake manifold purification apparatus evaporated the electromagnetic valve is opened, the activated carbon tank gasoline vapor drawn into the intake manifold to participate in combustion.
Gasoline is a volatile fuel, the fuel in the tank will evaporate quickly increasing the pressure inside the tank when the pressure reaches a certain value it will produce a certain risk, so people can find ways equilibrium pressure initially the fuel lid made of a pressure limiting valve, when the pressure is higher than a certain value, the pressure limiting valve is open, the gasoline vapor sent to the atmosphere, then, angles for fuel economy and environmental protection point of view, provided the carbon cans, filled inside the canister strong adsorption of activated carbon, excess fuel vapor in the fuel tank is no longer vented to the atmosphere, but rather the introduction of a tube charcoal canister. Is activated carbon adsorption of fuel vapor, automobile when actuated, timely charcoal canister solenoid valve is opened, the fuel vapor absorbed again poured into the intake manifold, in order to save fuel and environmental protection.
The principle and function
is part of the canister is actually part of the gasoline evaporation control system (the EVAP), the system is to avoid the engine is stopped after the fuel vapor from escaping into the the atmosphere citedInto which, since 1995, our new factory requiring all cars must have this system. First, we look at how it works, as shown in Figure 1: the engine stall, gasoline vapor tank mixed with the fresh air and stored in the carbon canister when the engine is started, and the feed contained in the charcoal canister electromagnetic valves between the manifold opening, the activated carbon tank gasoline vapor in the intake manifold vacuum is brought into action to participate in combustion of clean air into the cylinder. This not only reduces emissions, but also reduces fuel consumption.
-related failures and precautions:
Next we take a look at which faults associated with the canister, and the owners should pay attention to what the details to reducing the evaporation control system failure caused by:
the vehicle is traveling abnormal sound:
when the non-idle operation of the engine, from time to time can hear ldquo; da da rdquo; sound. Encounter with this situation do not panic, the first thing to do is find the car canister solenoid valve, the judge ldquo; da da rdquo; the sound is not the issue it, and if it does not have to care about the. Because, will produce intermittent switching operation canister solenoid valve opens the throttle, so that sound, but this is normal.
azole car stepped on the accelerator, the car greasy larger:
If you encounter step on the gas to accelerate the azole car, and the car’s gasoline relatively large fault, this time to pay special attention canister piping system is broken. Gasoline vapor directly into the atmosphere along breakage, resulting in large-car gasoline. And if the time line leak, causing the intake air into the engine rather than fuel vapor, the engine will inevitably result in too lean mixture, causing irregular azole car phenomenon.
fluctuated engine idling and weak acceleration:
If the engine is started, the idling rotational speed regularly fluctuated vehicle acceleration and weak, will have to pay attention to whether the canister is due the air inlet and filter blockage caused. Because, at this time outside air difficult to enter the canister, tank lack of fresh air, during idling, the intake under the action of vacuum suction, suction is drawn into the intake manifold in an activated carbon tank gasoline vapor, the oxygen sensor detects mixture is too thick, then the engine fuel injection control means reduces tolerance, this point may beConcentration of the mixed fuel gas decreases, resulting in low idle; And then, since the fuel injection amount decreases, the oxygen sensor is detected in the next cycle and the mixture too lean, thus increasing the fuel injection amount and the computer, and then led to the idling liter high, thus giving rise to idle speed regularly fluctuated phenomenon. So, when this happens, check the vehicle to timely canister intake inlet is smooth.
or difficult to start the engine stall:
At this time, will have to pay attention to check the canister solenoid valve may cause problems. If the solenoid valve has been closed, the fuel tank vapor carbon will be increasing more and eventually fill the canister, the remaining gasoline vapor can escape into the atmosphere, environmental pollution fuel waste. Conversely, if the solenoid valve has been opened the air-fuel mixture intake transient, the engine has been enriched in the state while the engine is not at this time because the control unit controls the work of the canister solenoid valve, and not it will issue a directive to reduce the fuel injection quantity, and this will result in hot car engine flameout caused by the mixture too thick, and after hot cars difficult to start flameout phenomenon.