| 摘要 |
Fuel control arrangements for gas turbine engines generally comprise an injector and a fuel control valve. Typically the fuel control valve is controlled in terms of fuel demand through fuel pressure presented to the valve. Fuel demand may vary and in such circumstances stagnation of fuel adjacent to the valve may cause degradation of the fuel and therefore spurious operational performance. By providing a dedicated working fluid, and typically hydraulic, pressure to the valve a variable aperture port can be displaced to alter the fuel flow configuration within the valve. In such circumstances different fuel valve conditions can be generated by altering the available area of aperture in the port to divert or present fuel to the injector between and across first or primary fuel paths and second or pilot fuel paths as required. Thus more flexibility with regard to fuel presentation to the injector is achieved as well as consistency with respect to avoiding fuel degradation as fuel demand varies. |
