Fuel vapor treatment apparatus

Abstract

A fuel vapor treatment apparatus includes a canister, a fuel vapor supply tube and a booster pump. The booster pump compresses fuel vapors retained in the canister and feeds the fuel vapors in the form of a compressed gas to fuel injectors of an engine via the fuel vapor supply tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Certain preferred embodiments of the present invention will be described in detail below, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic perspective view illustrating a vehicle employing a fuel supply apparatus with a fuel vapor treatment apparatus according to the present invention;

FIG. 2 is a diagrammatical view illustrating the fuel supply apparatus and an engine shown in FIG. 1;

FIG. 3 is a diagrammatical view illustrating the primary arrangement of the fuel supply apparatus and engine shown in FIG. 2;

FIG. 4 is a diagrammatical view illustrating the fuel vapor treatment apparatus shown in FIG. 3;

FIG. 5 is a diagrammatical view illustrating a modification of the fuel supply apparatus shown in FIG. 2;

FIG. 6 is a diagrammatical view illustrating the modified fuel vapor treatment apparatus shown in FIG. 5; and

FIG. 7 is a schematic view illustrating a fuel supply apparatus equipped with a conventional fuel vapor treatment apparatus.

Claims

1. A fuel vapor treatment apparatus comprising: a canister for temporarily retaining fuel vapors generated in a fuel tank;a first fuel vapor supply tube for allowing passage of the fuel vapors from the fuel tank to the canister;a second fuel vapor supply tube for allowing passage of the fuel vapors from the canister to fuel injectors of an engine; anda booster pump disposed on the second fuel vapor supply tube and adapted to suction outside air via the canister to purge the fuel vapors from the retention by the canister, to compress the purged fuel vapors and the suctioned outside air, and to feed the purged fuel vapors and the suctioned outside air in the form of a compressed gas to the fuel injectors via the second fuel vapor supply tube.

2. The treatment apparatus of claim 1, wherein the second fuel vapor supply tube is connected to a midway point of a fuel supply tube for supplying liquid fuel from the fuel tank to the fuel injectors, so that the purged fuel vapors are fed to the fuel injectors.

3. The treatment apparatus of claim 1, further comprising a controller for controlling a rate of discharge of the compressed gas from the booster pump in accordance with operating conditions when the engine is operating.

4. The treatment apparatus of claim 3, wherein the operating conditions include a level of opening of a throttle valve.

5. The treatment apparatus of claim 3, wherein the operating conditions include an engine speed.

6. The treatment apparatus of claim 1, further comprising: an amount detector for detecting an amount of the fuel vapors retained by the canister; and a controller for actuating the booster pump only when the amount of retention is greater than a predetermined reference retention amount.

7. The treatment apparatus of claim 1, further comprising: a refuel detector for detecting that the fuel tank is being refueled; and a controller for actuating the booster pump in accordance with a detection signal from the refuel detector.

8. The treatment apparatus of claim 7, wherein the refuel detector comprises a lid open/close sensor for detecting that the refueling lid, which is opened when fuel is to be fed from the exterior to the fuel tank, has been opened.

9. The treatment apparatus of claim 7, wherein the refuel detector comprises a fuel gauge for detecting a reservoir level of the fuel held in the fuel tank.

10. The treatment apparatus of claim 1, further comprising: an auxiliary fuel vapor supply tube branched from the second fuel vapor supply tube and connected to an intake system of the engine; and a purge valve disposed on the auxiliary fuel vapor supply tube and adapted to open when the booster pump is stopped.