| 摘要 |
A evaporated fuel processing device includes a seal valve that seals off the fuel tank from the atmosphere, a canister, a changeover valve that allows or inhibits communication of the canister with the atmosphere, the canister internal pressure sensor, a controller that sends an open/close command to the seal valve and the changeover valve, a diagnosis unit that performs leak diagnosis of an evaporated fuel sealing system, and a negative pressure pump that generates pressure in the evaporated fuel sealing system. The diagnosis unit performs leak diagnosis of the entirety of the evaporated fuel sealing system before performing leak diagnosis of a canister side section. The diagnosis unit performs function diagnosis of the seal valve with the seal valve closed and the changeover valve at a shut-off position based on whether the detection value of the tank internal pressure sensor varies beyond a predetermined range of the generated pressure. |
| 主权项 |
1. An evaporated fuel processing device comprising:
a seal valve disposed in a communication passage communicating a fuel tank with atmosphere, the fuel tank being mounted in a vehicle including an internal-combustion engine, the seal valve sealing off the fuel tank from the atmosphere; a canister disposed in the communication passage between the seal valve and the atmosphere, the canister collecting evaporated fuel vented from the fuel tank via the communication passage; a changeover valve disposed in the communication passage between the canister and the atmosphere, the changeover valve allowing or inhibiting the canister from communicating with the atmosphere; a canister internal pressure detecting unit disposed in a canister side section of the communication passage, the canister side section being one of two sections of the communication passage divided at a position of the seal valve and including the canister, the canister internal pressure sensor detecting a canister internal pressure of the canister, a tank internal pressure detecting unit configured to detect a tank internal pressure of the fuel tank; a controller configured to send a command to open or close the seal valve and a command to switch the changeover valve between an atmosphere communication position and an atmosphere shut-off position; a diagnosis unit configured to perform a leak diagnosis of an evaporated fuel sealing system including the fuel tank, the canister, and the seal valve; and a pressure generating unit configured to generate pressure in the evaporated fuel sealing system via the changeover valve, wherein the diagnosis unit performs a leak diagnosis of the entirety of the evaporated fuel sealing system using the pressure generating unit and the canister internal pressure detecting unit with the seal valve in open state and with the changeover valve at the atmosphere shut-off position in response to the command from the control unit, and wherein when the control unit closes the seal valve and, thereafter, sets the changeover valve at the atmosphere shut-off position, the diagnosis unit performs a function diagnosis of the seal valve by determining whether a detection value of the tank internal pressure detected by the tank internal pressure detecting unit varies beyond a predetermined range while the pressure generating unit generates pressure on condition that the seal valve is closed and the changeover valve is at the atmosphere shut-off position. |
