Patent ID: 7878179

Claim:
A fuel supply apparatus comprising: a fuel pump connected to a fuel delivery pipe for delivering a fuel to an internal combustion engine; a pressure regulator constructed to adjust a pressure of the fuel fed through the fuel delivery pipe, wherein the fuel pump and the pressure regulator are disposed within a fuel tank; wherein the pressure regulator comprises: a first pressure chamber including a return port for returning the fuel into the fuel tank; a second pressure chamber; a third pressure chamber; a valve assembly including a valve member capable of opening and closing the return port, a pressure receiving member and a connecting rod connecting between the valve member and the pressure receiving member, so that the valve member can move together with the pressure receiving member; a first diaphragm having a first pressure receiving area and constructed to separate the first pressure chamber and the second pressure chamber from each other and to resiliently support the valve member; a second diaphragm having a second pressure receiving area and constructed to separate the second pressure chamber and the third pressure chamber from each other, wherein first pressure receiving area and the second pressure receiving area are different from each other; a first introduction passage connecting between the fuel pump and the first pressure chamber; a second introduction passage connecting between the fuel pump and the second pressure chamber; a third introduction passage connecting between the fuel pump and the third pressure chamber; and a changeover device operable to selectively permit or prevent communication between the second introduction passage and the second pressure chamber and to selectively permit or prevent communication between the third introduction passage and the third pressure chamber, so that the fuel from the fuel pump can be selectively introduced into the second pressure chamber and can be selectively introduced into the third pressure chamber for adjusting a supply pressure of the fuel fed through the fuel delivery pipe to any one of a first level, a second level lower than the first level, and a third level lower than the second level.