Patent Application
20080060618
These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
An explanation of an embodiment of the present invention will be given below with reference to the drawing.
In a fuel system for an outboard motor 10, fuel accumulated in a fuel tank 11 is supplied, by a low pressure pump (F/P) 12 to a vapor separator tank 13 provided in a cowling of the outboard motor. A chassis 14 of the vapor separator tank 13 is, for example, made of resin, and an inner portion of the chassis 14 is hermetically divided by a wall 14W into a fuel accumulating chamber 15 and a canister chamber 16.
The low pressure pump 12 supplies fuel to the fuel accumulating chamber 15 of the vapor separator tank 13, and a needle valve 17 is provided in a fuel supply port of the fuel accumulating chamber 15. The needle valve 17 is linked to a float arm 19 which supports a float 18 disposed in the fuel accumulating chamber 15, and the needle valve 17 opens and closes the fuel supply port in accordance with the height of the float 18.
More specifically, one end of the float arm 19 is axially supported by the chassis 14, and the other end is linked to the float 18. The float 18 rises and falls in accordance with the height of the liquid surface of the fuel accumulated in the fuel accumulating chamber 15, the needle valve 17 linked to the float arm 19 opens the fuel supply port when the height of the liquid surface is a prescribed value or less, thus causing fuel to flow, and closes the fuel supply port when the height of the liquid surface is greater than, the prescribed value, thus causing supply of the fuel to cease. In this manner, the height of the liquid surface in the fuel accumulating chamber 15 is maintained at a fixed height. Note that the upstream and downstream sides of the low pressure valve 12 are connected to each other through a relief valve (L/V) 20, and when the fuel pressure on the downstream side reaches a prescribed value, the relief valve 20 opens, and fuel returns to the upstream side.
A high pressure pump (F/P) 21 is disposed in the fuel accumulating chamber 15. The high pressure pump 21 supplies fuel accumulated in the fuel accumulating chamber 15 to an injector (INJ) 22. The high pressure pump 21 is supplied with power by a power source B, and the operation of the high pressure pump 21 is controlled by an electronic control unit (ECU) 23. Note that the injector 22 injects fuel at a prescribed timing into the intake pipe of an engine (E/G) 24. Moreover, a pressure regulator (P/R) 25 is connected to the injector 22 to regulate the injection pressure of the injector 22, and the pressure regulator 25 is also connected to the fuel accumulating chamber 15.
On the uppermost surface which forms an upper lid of the chassis 14, a communication passage 26 is integrally formed with the upper lid so that the fuel accumulating chamber 15 and the canister chamber 16 communicate. A check valve 27 is provided in the opening of the communication passage 26 that opens into the fuel accumulating chamber 15. When the pressure of the fuel which evaporated in the fuel accumulating chamber 15 exceeds a prescribed value, the check valve 27 opens, and the evaporated gas in the fuel accumulating chamber 15 is ejected to the canister chamber 16 through the communication passage 26.
Moreover, a first outlet 28 is provided on the uppermost surface (upper lid) of the canister chamber 16 and is linked to the intake pipe of the engine 24 via a duct. More specifically, the evaporated gas supplied to the canister chamber 16 is ejected to the intake pipe through the first outlet 28 due to the negative pressure of the intake pipe when the engine 24 is operating.
The canister chamber 16 is filled with activated charcoal 29, and a second outlet 30 is provided on the bottom surface of the canister chamber 16. The second outlet 30 is connected to the downstream side of a drain valve 31 provided for releasing the fuel in the fuel accumulating chamber 15, and beyond the drain valve 31 the second outlet 30 is connected to a scavenging passage (not shown in the drawing).
More specifically, when the engine 24 is not in operation, the evaporated gas ejected into the canister chamber 16 passes through the evaporated charcoal 29 layer and is ejected to the scavenging passage from the second outlet 30. At this time, the activated charcoal 29 absorbs and eliminates pollutants, odors and the like included in the evaporated gas.
In the above manner, the vapor separator tank of the present embodiment integrates the fuel accumulating chamber and the canister chamber and thus reduces the size and the cost of the device. Moreover, the communication passage connecting the fuel accumulating chamber and the canister chamber is integrated with the upper lid of the vapor separator tank, thus the various ducts are simplified, and the degree of freedom when designing the layout is increased. Moreover the chassis of the vapor separator tank is made of resin, thus the heat insulating effect is high and the amount of evaporated gas is lowered.
In the present embodiment as described, the fuel accumulating chamber and the canister chamber are completely integrated. However, it is also possible to achieve integration using a cassette structure in which the canister chamber is detachable from the fuel accumulating chamber. With such a cassette structure, it is possible to vary the size of the canister chamber as appropriate to make the canister chamber easy to replace. Moreover, it is possible to reduce the amount of hydrocarbons emitted by the entire ship body by employing a structure which allows communication between the canister chamber and a hermetically sealed fuel tank using a hose or the like.
Furthermore, a structure may also be employed in which the canister chamber encloses the periphery of the fuel accumulating chamber, and in this case a heat insulating effect is obtained from the atmosphere in the canister chamber when there is dead soak or the like.
Although a few embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-246883 | Sep 2006 | JP | national |
