| 摘要 |
The present invention provides a two stage fuel pump which is particularly suited for piston aircraft engines. The fuel pump includes a housing having a fuel inlet and a fuel outlet where the fuel inlet is open to a cylindrical swirl chamber formed in the housing. The first pump stage has its inlet open to the inlet chamber and its outlet open to an intermediate chamber formed in the housing. The second pump stage has its inlet open to the intermediate chamber while its outlet is fluidly connected through a fuel control valve to the fuel outlet. A pressure responsive valve is fluidly connected between the intermediate chamber and inlet chamber and recirculates fuel from the intermediate chamber and to the inlet chamber whenever the pressure in the intermediate chamber exceeds a predetermined pressure. In addition, the fuel control valve is responsive to an engine condition, such as a turbo charger outlet pressure, to variably recirculate a portion of the fuel from the second stage pump outlet to the inlet chamber. |
