The function of the fuel evaporation control system is to prevent the gasoline vapor evaporated in the car's fuel tank from being discharged into the atmosphere. It consists of a steam recovery tank (also called activated carbon tank), control solenoid valve, steam separation valve, and corresponding steam pipeline and vacuum hose. The steam separation valve is installed on the top of the oil tank, and the gasoline vapor in the oil tank enters the steam recovery tank from the valve outlet through the pipeline. The function of the valve is to prevent the fuel in the fuel tank from leaking out of the steam pipeline when the car is tipped. The steam recovery tank is filled with activated carbon particles, so it is also called activated carbon tank. Activated carbon can adsorb gasoline molecules in gasoline vapor. When the gasoline vapor in the fuel tank enters the vapor recovery tank through the vapor pipeline, the gasoline molecules in the vapor are adsorbed by the activated carbon.
The other outlet above the steam recovery tank communicates with the engine intake manifold via a vacuum hose. There is a solenoid valve in the middle of the hose to control the on-off of the pipeline. When the engine is running, if the solenoid valve is opened, under the effect of the vacuum suction of the intake manifold, fresh air will enter from below the vapor recovery tank, and after passing through the activated carbon, the engine intake manifold will enter the hose from the vapor recovery tank outlet The gasoline molecules (re-evaporated) adsorbed on the activated carbon are sent to the engine for combustion to make full use of it; the activated carbon in the steam recovery tank will then restore the adsorption capacity and will not fail due to long use.
The amount of recovered fuel vapor entering the intake manifold must be controlled to prevent damage to normal gas mixture components. This control process is realized by the microcomputer by manipulating and controlling the opening and closing of the solenoid valve according to the operating parameters of the engine such as the water temperature, speed, throttle opening degree and the like. When the engine is stopped or idling, the microcomputer closes the solenoid valve, and the fuel vapor escaping from the fuel tank is absorbed by the activated carbon in the vapor recovery tank. When the engine is running at medium and high speeds, the microcomputer opens the solenoid valve, and the gasoline vapor stored in the vapor recovery tank is drawn into the engine after passing through the vacuum hose. At this time, because the intake air volume of the engine is large, a small amount of fuel vapor will not affect the composition of the mixture.
2. Detection of fuel evaporation control system
For the failure of the fuel evaporation control system, the microcomputer cannot generally diagnose by itself, and can only use the on-board inspection and single-piece inspection methods to find out.
1. On-board inspection
Vehicle inspection can be carried out in the following order:
(1) Warm up the engine to normal operating temperature and let it run at idle speed.
(2) Unplug the vacuum hose on the vapor recovery tank and check for vacuum suction in the hose. If the fuel evaporation control system is working properly, the solenoid valve should be closed during engine idling and no vacuum suction in the vacuum hose. If there is vacuum suction in the vacuum hose at this time, use the multimeter V file to check whether there is voltage on the solenoid valve harness connector terminal. If there is voltage on the solenoid valve harness connector terminal, it means that the microcomputer is faulty; if there is no voltage, it means that the solenoid valve is faulty (stuck in the open position).
(3) Depress the accelerator pedal, and when the engine speed is greater than 200 Or / min, check the vacuum hose for vacuum suction. If there is vacuum suction in the vacuum hose, it means that the system is working properly; if there is no vacuum suction in the vacuum hose, use the multimeter V file to check whether there is voltage on the solenoid valve harness connector terminal. If the voltage is normal, the solenoid valve is faulty; if the voltage is abnormal, the microcomputer or control circuit is faulty.
2. Single piece detection of solenoid valve
(1) Check the resistance value of the solenoid coil of the solenoid valve. Unplug the solenoid valve harness connector, and use a multimeter to measure the resistance of the solenoid valve solenoid coil. The resistance value should meet the regulations, otherwise the solenoid valve should be replaced.
(2) Check the operation of the solenoid valve. Remove the solenoid valve, first blow into the solenoid valve, the solenoid valve should not be ventilated; then add the battery voltage to the two terminals of the solenoid valve connector, and at the same time blow into the solenoid valve, at this time the electromagnetic circle should be ventilated. If the state of the solenoid valve does not match the above, the solenoid valve is faulty and should be replaced.
This POWER Bank possesses a lithium ion battery at its core, which takes
up to five hours to be completely charged. As for the output charging
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The input
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