Operational signal stability means for turbine

In a gas turbine engine having at least one compressor connected to a power turbine, a housing with a first chamber and a second chamber located therein, a main fuel passage connected to a source of fuel, a metering valve located in said main fuel passage for controlling the flow of fuel from the source to a combustion chamber, said compressor rotating as a result of the combustion of fuel in the combustion chamber to develop a compressor discharge pressure Pc in a first operational fluid and oil pressure Po in second operational fluid, said power turbine responding to the development of said compressor discharge pressure by rotating, a control system for operating said metering valve in accordance with a fuel supply schedule corresponding to a desired rotational speed for said compressor, first bellows means for separating a first chamber from a second chamber and being connected to said metering valve, a first passageway for communicating compressor discharge pressure Pc to said first chamber, a first bleed orifice through which said first passageway is connected to a second passageway connected with said second chamber and to a second bleed orifice through which said second passageway is communicated to the surrounding environment, first governor means having a first lever arrangement having a face on the end thereof which is located adjacent said second bleed orifice, said first lever arrangement being responsive to an input signal applied to a power lever by an operator and the rotational speed of said compressor for controlling flow of operational fluid from said second passageway through said second bleed orifice to establish an operational fluid pressure Py in the operational fluid presented to said second chamber, said bellows means responding to a pressure differential between compressor discharge Pc in the first chamber and an operational pressure Py in the second chamber to provide said metering valve with an operation input to control fuel supplied to said combustion chamber in accordance with the fuel supply schedule, second governor means responsive to the rotational speed of said power turbine having a second lever arrangement with a first face thereon which is located adjacent a third bleed orifice connected to said second passageway and a second face thereon which is located adjacent a fourth bleed orifice connected to a third passageway, pressure regulator means connected to receive compressor discharge pressure Pc and develop a regulated pressure Pr, a fifth bleed orifice through which regulated pressure Pr is presented to said third passageway, said first face on said second lever controlling the flow of operational fluid through said third bleed orifice from said second passageway as a function of the rotational speed of said power turbine and said second face on said second lever controlling the flow of regulated pressure Pr through said fourth bleed orifice to create a control pressure Pg, reset means connected to said first lever means and responsive to a pressure differential developed between said regulated pressure Pr and control pressure Pg for controlling the development of said operational pressure Py as a function of the rotational speed of said power turbine, limiter means connected to said third passageway for limiting the communication of said control pressure Pg to said reset means as a function of the development of said oil pressure Po in said second operational fluid, the improvement comprising:

• accumulator means connected to said third passageway and responsive to a predetermined fluid pressure Po of said second operational fluid for increasing the volume of operational fluid at control pressure Pg to modify the time constants in operating said reset means and change the operation of said control means such that the fuel supplied to said combustion chamber provides a smooth operation of said gas turbine engine.