A gas turbine engine includes at least one shaft that interconnects a compressor section and a turbine section. A starter turbine provides torque to the at least one shaft during an engine start event. The starter turbine includes an air inlet and an outlet. A buffer air system is in fluid communication with the starter turbine and is configured to receive air associated with the outlet to supplement sealing of a bearing compartment sealing system.

A starter supplemental lubrication system for a gas turbine engine is provided. The starter supplemental lubrication system includes a pneumatic starter operable to drive rotation of a rotor shaft of a gas turbine engine through an accessory gearbox. The pneumatic starter is configured to receive a primary lubricant flow at a first rotational speed range and receive a supplemental lubricant flow at a second rotational speed range that is less than the first rotational speed range. The starter supplemental lubrication system also includes a supplemental lubricant pump operable to supply the supplemental lubricant flow at the second rotational speed range. The supplemental lubricant pump is internal to the pneumatic starter.

A starter supplemental lubrication system for a gas turbine engine is provided. The starter supplemental lubrication system includes a pneumatic starter operable to drive rotation of a rotor shaft of a gas turbine engine through an accessory gearbox. The pneumatic starter is configured to receive a primary lubricant flow at a first rotational speed range and receive a supplemental lubricant flow at a second rotational speed range that is less than the first rotational speed range. The starter supplemental lubrication system also includes a supplemental lubricant pump operable to supply the supplemental lubricant flow at the second rotational speed range. The supplemental lubricant pump is internal to the pneumatic starter.

A rotary valve system includes a first body having a first plurality of fluid channels. The first fluid channels have a common first inlet to receive a fluid and a first outlet. The system includes a second body coupled to the first body. The second body has a second plurality of fluid channels. The second fluid channels have a second inlet and a second outlet. The system includes a plate assembly having a plate coupled between the first body and the second body. The plate is movable between at least a first, open position in which the first outlet of at least one of the first fluid channels is in fluid communication with the second inlet of at least one of the second fluid channels and a second, closed position in which the second inlet of each of the second fluid channels is substantially completely obstructed by the plate.

An air turbine starter that includes a housing. The housing can circumscribe a turbine coupled that is coupled to a gear train in a gear box via a drive shaft. The gear train can couple to an output shaft via at least a carrier. The air turbine starter can include at least a first bearing assembly and a second bearing assembly to rotatably support the drive shaft and the output shaft.

An air turbine starter that includes a housing. The housing can circumscribe a turbine coupled that is coupled to a gear train in a gear box via a drive shaft. The gear train can couple to an output shaft via at least a carrier. The air turbine starter can include at least a first bearing assembly and a second bearing assembly to rotatably support the drive shaft and the output shaft.

The gas turbine engine can have a bearing cavity, an ejector having an air/oil path fluidly connected to the bearing cavity, and a nozzle fluidly coupled with the air/oil path, the nozzle connected to a compressed air source.

The gas turbine engine can have a bearing cavity, an ejector having an air/oil path fluidly connected to the bearing cavity, and a nozzle fluidly coupled with the air/oil path, the nozzle connected to a compressed air source.

The method can include generating a first duty cycle value for the PWM; monitoring a current value of a parameter; generating a duty cycle limit value for the PWM, including activating more than one duty cycle limit functions based on corresponding activation conditions, the corresponding activation conditions based on the current value of the parameter, each of the more than one duty cycle limit functions generating a corresponding duty cycle limit subvalue when the corresponding activation conditions are met, and setting the duty cycle limit value to a sum of the generated duty cycle limit subvalues; setting a second duty cycle value for the PWM, as the first duty cycle value or as the duty cycle limit if the first duty cycle value exceeds the duty cycle limit; and, applying the PWM at the second duty cycle value to the valve.

The method can include generating a first duty cycle value for the PWM; monitoring a current value of a parameter; generating a duty cycle limit value for the PWM, including activating more than one duty cycle limit functions based on corresponding activation conditions, the corresponding activation conditions based on the current value of the parameter, each of the more than one duty cycle limit functions generating a corresponding duty cycle limit subvalue when the corresponding activation conditions are met, and setting the duty cycle limit value to a sum of the generated duty cycle limit subvalues; setting a second duty cycle value for the PWM, as the first duty cycle value or as the duty cycle limit if the first duty cycle value exceeds the duty cycle limit; and, applying the PWM at the second duty cycle value to the valve.