CPC F02C 9/263 (2013.01) [F02C 7/232 (2013.01); F02C 9/46 (2013.01); F05D 2260/84 (2013.01); F23R 3/346 (2013.01)] | 18 Claims |
1. A fuel metering system for a multi-stage combustion system having a main combustion stage and at least one secondary combustion stage, comprising:
a main fuel metering system configured to supply fuel to the main combustion stage, the main fuel metering system having a main electro-hydraulic servo valve (EHSV) fluidly coupled to a main system fuel metering valve (FMV) through a transfer valve; and
a secondary fuel metering system configured to supply fuel to the secondary combustion stage, the secondary fuel metering system having a secondary electro-hydraulic servo valve (EHSV) fluidly coupled to a secondary fuel metering valve (FMV) and to the main system fuel metering valve (FMV) through the transfer valve; and
wherein the transfer valve includes a multi-land piston configured to provide control pressures from the main EHSV to the main FMV to control positioning thereof during a normal mode of operation, and to provide control pressures from the secondary EHSV to the main FMV to control positioning thereof during a backup mode of operation.
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