On-board leak diagnosis device and fuel evaporation control system

Abstract

The invention relates to a vehicle-mounted leakage diagnosis device and a fuel evaporation control system. The vehicle-mounted leakage diagnosis device includes an upper end cover, a booster pump assembly, a valve body, a lower end cover, a sliding float and a miniature spring. The upper end cover is provided with a first pipe joint , there is a second pipe joint on the valve body; when the power is not on, the booster pump assembly does not work, the airflow enters from the first pipe joint, and directly flows into the passage of the second pipe joint, and the carbon tank and the ash filter are directly connected, so that The ventilation pressure drop of the fuel evaporation control system is small; after power on, the airflow compressed by the booster pump enters the fuel evaporation control system, because the output flow of the booster pump is a constant value, when the fuel evaporation system reaches the set pressure The time required is the test value, so the time taken to reach a certain pressure when the standard hole is connected to the empty fuel tank can be preset as the reference value; if the test value is greater than the reference value, the ECU judges that the system is leaking, otherwise it judges that the system is not leaking.

Description

technical field [0001] The invention relates to the technical field of vehicle fuel vapor leakage diagnosis, in particular to a vehicle-mounted leakage diagnosis device and a fuel evaporation control system. Background technique [0002] The fuel evaporation control system usually consists of a fuel tank assembly, a carbon canister assembly, an ash filter, a canister desorption control valve and its connecting pipelines. If any part of the fuel evaporation control system leaks, the environment will be polluted. Therefore, the new emission regulations have clearly required the on-board automatic diagnostic system (OBD) to identify and signal possible leaks, and then provide the corresponding data to the on-board memory for offline diagnosis in the factory. [0003] The prior art discloses a leakage detection system for a fuel tank of a vehicle, which can diagnose whether there is leakage in the fuel system by utilizing the pressure signal change caused by the natural vacuum ...

AI Technical Summary

Problems solved by technology

Although it can achieve the goal of low cost, but it consists of relatively many parts, which is inconvenient for later maintenance of the device

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