Lubrication system for gas turbine engines

Abstract

A method of controlling lubrication flow to a first engine component, a second engine component and a lubrication tank of a gas turbine engine according to an example of the present disclosure includes, among other things, determining more than one condition experienced by the gas turbine engine, comparing with a processor on a controller the more than one condition against an engine performance model stored in memory on the controller, wherein the engine performance model includes stored relationship values between the more than one condition and a position of a scheduling valve, the scheduling valve disposed between the lubricant tank and the first engine component and between the lubricant tank and the second engine component, pumping a lubricant from the lubricant tank through a conduit to the scheduling valve using a pump, and controlling the position of the scheduling valve to vary a flow of the lubricant to two or more of the first engine component, the second engine component and the lubrication tank based upon the comparing of the more than one condition experienced by the gas turbine engine.

1 - 30 . (canceled) 
     
     
         31 . A turbofan gas turbine engine, comprising:
 a fan section including a fan and an outer housing surrounding the fan to define a bypass duct, and a fan pressure ratio of less than 1.45 across the fan blade alone at a cruise condition at 0.8 Mach and 35,000 feet;   a compressor section including a first compressor and a second compressor;   a combustion section including a combustor downstream of the compressor section;   a turbine section including a fan drive turbine and a second turbine;   a lubrication system including a pump that moves a lubricant and a lubricant tank that stores the lubricant;   a first engine component and a second engine component each requiring lubrication from the lubricant, wherein the first engine component is a fan drive gear system that allows the fan to rotate at a different angular speed from a spool;   a conduit between the lubricant tank and the first engine component and between the lubricant tank and the second engine component;   a scheduling valve positioned in the conduit between the lubricant tank, and the first engine component and the second engine component; and   a controller including a memory and a processor that controls the scheduling valve, wherein the memory includes stored relationship values between more than one condition experienced by the turbofan gas turbine engine in operation and a position of the scheduling valve, and wherein the controller commands the scheduling valve to vary a flow of the lubricant to the first engine component, the second engine component and the lubricant tank in response to the more than one condition.   
     
     
         32 . The turbofan gas turbine engine as recited in  claim 31 , wherein the spool is a low spool including a shaft that interconnects the fan drive gear system and the fan drive turbine. 
     
     
         33 . The turbofan gas turbine engine as recited in  claim 32 , wherein the more than one condition includes a first condition relating to the angular speed of the fan. 
     
     
         34 . The turbofan gas turbine engine as recited in  claim 33 , wherein the first condition includes a calculated engine torque, and wherein the calculated engine torque includes a calculated torque for the fan, the fan drive gear system or the low spool. 
     
     
         35 . The turbofan gas turbine engine as recited in  claim 32 , wherein the fan drive gear system comprises an epicyclic gear train. 
     
     
         36 . The turbofan gas turbine engine as recited in  claim 35 , wherein the fan drive turbine drives the first compressor and the fan drive gear system. 
     
     
         37 . The turbofan gas turbine engine as recited in  claim 31 , wherein the more than one condition includes two or more of: a calculated engine torque, an engine startup condition of the turbofan gas turbine engine, an altitude of the turbofan gas turbine engine, a vibration level of the turbofan gas turbine engine, the cruise condition, a weight on wheels condition of an aircraft on which the turbofan gas turbine engine is mounted, and a burner pressure condition of the combustor. 
     
     
         38 . The turbofan gas turbine engine as recited in  claim 37 , wherein the scheduling valve is moveable between a plurality of positions including first and second positions, the controller commands the scheduling valve to communicate the lubricant to the first component but not the second component in the first position, and the controller commands the scheduling valve to communicate the lubricant to both the first and second components in the second position. 
     
     
         39 . The turbofan gas turbine engine as recited in  claim 38 , wherein the more than one condition includes the calculated engine torque, and wherein the calculated engine torque includes a calculated torque for the fan. 
     
     
         40 . The turbofan gas turbine engine as recited in  claim 39 , wherein the plurality of positions includes a third position, and the controller commands the scheduling valve to communicate the lubricant to the second component but not the first component in the third position. 
     
     
         41 . The turbofan gas turbine engine as recited in  claim 40 , wherein the plurality of positions includes a fourth position, and the controller commands the scheduling valve to communicate the lubricant to the lubricant tank but not the first and second components in the fourth position. 
     
     
         42 . The turbofan gas turbine engine as recited in  claim 37 , comprising a plurality of sensors that each provide data about a state of the turbofan gas turbine engine that indicates one of the more than one condition. 
     
     
         43 . The turbofan gas turbine engine as recited in  claim 42 , wherein the more than one condition includes the vibration level, and the vibration level corresponds to a vibration level of the fan drive gear system. 
     
     
         44 . The turbofan gas turbine engine as recited in  claim 43 , wherein the plurality of sensors includes a vibration sensor that is used to gather data indicating the vibration level of the fan drive gear system. 
     
     
         45 . The turbofan gas turbine engine as recited in  claim 44 , wherein the vibration sensor is an accelerometer. 
     
     
         46 . The turbofan gas turbine engine as recited in  claim 44 , wherein the vibration sensor is positioned in the fan drive gear system. 
     
     
         47 . The turbofan gas turbine engine as recited in  claim 46 , wherein the vibration sensor is an accelerometer. 
     
     
         48 . The turbofan gas turbine engine as recited in  claim 42 , wherein the more than one condition includes the calculated engine torque, and the calculated engine torque includes a calculated torque for the fan. 
     
     
         49 . The turbofan gas turbine engine as recited in  claim 48 , wherein the spool is a low spool including a shaft that interconnects the fan drive gear system and the fan drive turbine. 
     
     
         50 . The turbofan gas turbine engine as recited in  claim 49 , wherein the plurality of sensors includes an RPM sensor. 
     
     
         51 . The turbofan gas turbine engine as recited in  claim 49 , wherein the more than one condition includes the altitude of the turbofan gas turbine engine. 
     
     
         52 . The turbofan gas turbine engine as recited in  claim 51 , wherein the more than one condition includes the cruise condition. 
     
     
         53 . The turbofan gas turbine engine as recited in  claim 49 , wherein the more than one condition includes the burner pressure condition. 
     
     
         54 . The turbofan gas turbine engine as recited in  claim 53 , wherein the more than one condition includes the engine startup condition, the altitude of the turbofan gas turbine engine, the cruise condition, the vibration level of the turbofan gas turbine engine, and the weight on wheels condition. 
     
     
         55 . The turbofan gas turbine engine as recited in  claim 54 , wherein the vibration level corresponds to a vibration level of the fan drive gear system, and the plurality of sensors includes a vibration sensor that is used to gather data indicating the vibration level of the fan drive gear system. 
     
     
         56 . The turbofan gas turbine engine as recited in  claim 55 , wherein the vibration sensor is positioned in the fan drive gear system. 
     
     
         57 . The turbofan gas turbine engine as recited in  claim 56 , wherein the vibration sensor is an accelerometer. 
     
     
         58 . The turbofan gas turbine engine as recited in  claim 53 , wherein the lubrication system includes a de-aerator, a filter and a cooler each between the lubricant tank and the first engine component, and each between the lubricant tank and the second engine component. 
     
     
         59 . The turbofan gas turbine engine as recited in  claim 58 , wherein the scheduling valve is moveable between a plurality of positions including first, second, third and fourth positions, wherein the controller commands the scheduling valve to communicate the lubricant to the first component but not the second component in the first position, wherein the controller commands the scheduling valve to communicate the lubricant to both the first and second components in the second position, wherein the controller commands the scheduling valve to communicate the lubricant to the second component but not the first component in the third position, and wherein the controller commands the scheduling valve to communicate the lubricant to the lubricant tank but not the first and second components in the fourth position. 
     
     
         60 . The turbofan gas turbine engine as recited in  claim 59 , wherein the pump is driven by a rotating component of the gas turbine engine, and the pump supplies a varying flow of the lubricant to the scheduling valve in operation.