초록 ▼

An aircraft fuel system is provided and includes a metering valve having inlet and outlet sides to monitor fuel flow from the inlet to the outlet side, a check valve that, when opened, allows fuel to flow toward the inlet side during start and climb conditions and, when closed, prevents such fuel fl

An aircraft fuel system is provided and includes a metering valve having inlet and outlet sides to monitor fuel flow from the inlet to the outlet side, a check valve that, when opened, allows fuel to flow toward the inlet side during start and climb conditions and, when closed, prevents such fuel flow and an ejector pump, which is operably disposed between the check valve and the metering valve, and which, with the check valve closed, pumps fuel toward the inlet side during idle conditions.

대표청구항 ▼

1. An aircraft fuel system, comprising: a metering valve having inlet and outlet sides to control fuel flow from the inlet to the outlet side;a check valve that, when opened, allows fuel to flow toward the inlet side during start and climb conditions and, when closed, prevents such fuel flow;an ejec

1. An aircraft fuel system, comprising: a metering valve having inlet and outlet sides to control fuel flow from the inlet to the outlet side;a check valve that, when opened, allows fuel to flow toward the inlet side during start and climb conditions and, when closed, prevents such fuel flow;an ejector pump, which is operably disposed between the check valve and the metering valve, and which, with the check valve closed, pumps fuel toward the inlet side during idle conditions; anda pressure regulating valve (PRV) to restrict fuel flow from main and auxiliary pumps, which are disposed to pump fuel along separate fuel lines to the inlet side in accordance with a pressure differential between the outlet side and fuel pumped by the auxiliary pump, the PRV comprising:first and second connected piston heads elastically anchored to a first valve end and biased toward a second valve end,the second piston head having a groove that fluidly communicates with a conduit by which excess fuel pumped by the auxiliary pump is bypassed from the inlet side with the first and second piston heads moved toward the first valve end by a first distance from the second valve end, andthe first piston head having a groove that fluidly communicates with a conduit by which excess fuel pumped by the main pump is bypassed from the inlet side with the first and second piston heads only moved toward the first valve end by a second distance from the second valve end, which is larger than the first distance. 2. The aircraft fuel system according to claim 1, wherein: the main pump pumps fuel toward the inlet side, andthe auxiliary pump is operably disposed downstream from the check valve and the ejector pump to pump fuel provided via the check valve or the ejector pump toward the inlet side. 3. The aircraft fuel system according to claim 2, wherein, during the start condition, substantially all of the fuel pumped by the main and the auxiliary pumps is permitted to be pumped to the inlet side. 4. The aircraft fuel system according to claim 2, wherein, during the climb condition, substantially all of the fuel pumped by the main pump is permitted to be pumped to the inlet side and excess fuel pumped by the auxiliary pump is bypassed by the PRV. 5. The aircraft fuel system according to claim 2, wherein during the idle conditions, substantially all of the fuel pumped by the auxiliary pump and excess fuel pumped by the main pump is bypassed by the PRV. 6. The aircraft fuel system according to claim 2, wherein, during the start and climb conditions, the PRV permits substantially all of the fuel pumped by the main pump to reach the inlet side. 7. The aircraft fuel system according to claim 6, wherein, during the idle conditions, the PRV directs excess fuel pumped by the main pump toward the check valve. 8. The aircraft fuel system according to claim 7, wherein, during the idle conditions, the PRV directs excess fuel pumped by the auxiliary pump toward the ejector pump. 9. An aircraft engine fuel system, comprising: a metering valve having inlet and outlet sides to control fuel flow from the inlet to the outlet side;main and auxiliary pumps to pump first and second fuel along separate fuel lines toward the inlet side, respectively;a pressure regulating valve (PRV) operably disposed between the main pump and the inlet side to restrict the first fuel flow in accordance with a pressure differential between the outlet side and second fuel pressure and to force a portion of the first fuel into a bypass condition;a check valve, coupled to the pressure regulating valve, which, when closed restricts a flow of the bypassed portion of the first fuel toward the auxiliary pump; andan ejector pump, operably disposed between the check valve and the auxiliary pump,which, when the check valve is closed, pumps second fuel from the pressure regulating valve toward the auxiliary pump,wherein the PRV comprises:first and second connected piston heads elastically anchored to a first valve end and biased toward a second valve end,the second piston head having a groove that fluidly communicates with a conduit by which excess fuel pumped by the auxiliary pump is bypassed from the inlet side with the first and second piston heads moved toward the first valve end by a first distance from the second valve end, andthe first piston head having a groove that fluidly communicates with a conduit by which excess fuel pumped by the main pump is bypassed from the inlet side with the first and second piston heads only moved toward the first valve end by a second distance from the second valve end, which is larger than the first distance. 10. The aircraft fuel system according to claim 9, wherein the check valve opens to allow the bypassed portion of the first fuel to flow toward the auxiliary pump during start and climb conditions and, when closed, prevents such first fuel flow. 11. The aircraft fuel system according to claim 10, wherein the ejector pump pumps fuel toward the inlet side during idle conditions with the check valve closed while maintaining metered fuel pressure during auxiliary pump unloading. 12. The aircraft fuel system according to claim 11, wherein, during the start condition, substantially all of the first and second fuel pumped by the main and the auxiliary pumps, respectively, is permitted to be pumped to the inlet side. 13. The aircraft fuel system according to claim 11, wherein, during the climb condition, substantially all of the first fuel pumped by the main pump is permitted to be pumped to the inlet side and excess second fuel pumped by the auxiliary pump is bypassed by the PRV. 14. The aircraft fuel system according to claim 11, wherein during the idle conditions, substantially all of the second fuel pumped by the auxiliary pump and excess first fuel pumped by the main pump is bypassed by the PRV. 15. The aircraft fuel system according to claim 11, wherein, during the start and climb conditions, the PRV permits substantially all of the first fuel pumped by the main pump to reach the inlet side. 16. The aircraft fuel system according to claim 15, wherein, during the idle conditions, the PRV directs excess first fuel pumped by the main pump toward the check valve. 17. The aircraft fuel system according to claim 16, wherein, during the idle conditions, the PRV directs excess second fuel pumped by the auxiliary pump toward the ejector pump. 18. An aircraft engine fuel system, comprising: a first valve to control fuel flow;first and second pumps to pump fuel toward the first valve;second and third valves to regulate an amount of fuel permitted to be pumped to an inlet side of the first valve, the second valve comprising first and second connected piston heads elastically anchored to a first valve end and biased toward a second valve end, the second piston head having a groove that fluidly communicates with a conduit by which excess fuel pumped by the second pump is bypassed from the inlet side with the first and second piston heads moved toward the first valve end by a first distance from the second valve end, and the first piston head having a groove that fluidly communicates with a conduit by which excess fuel pumped by the first pump is bypassed from the inlet side with the first and second piston heads only moved toward the first valve end by a second distance from the second valve end, which is larger than the first distance; anda third pump operably disposed between the third valve and the second pump to pump a portion of fuel toward the second pump, wherein the second valve is configured:with the grooves non-communicative with the conduits during start conditions such that substantially all of the fuel pumped by the first and second pumps is permitted to be pumped to the first valve,with the groove of the second piston head fluidly communicative with the conduit by which excess fuel pumped by the second pump is bypassed from the inlet side during climb conditions such that substantially all of the fuel pumped by the first pump is permitted to be pumped to the first valve and excess fuel pumped by the second pump is bypassed between a valve wall and the second piston head to the third pump, andwith the groove of the first piston head fluidly communicative with the conduit by which excess fuel pumped by the first pump is bypassed from the inlet side during idle conditions such that substantially all of the fuel pumped by the second pump is bypassed between the valve wall and the second piston head to the third pump and excess fuel pumped by the first pump is bypassed between the valve wall and the first grooved piston head to the first pump. 19. The aircraft engine fuel system according to claim 18, wherein the third valve opens during the start and climb conditions and the excess fuel pumped by the second pump is bypassed toward the third pump. 20. The aircraft engine fuel system according to claim 19, wherein the third valve closes during the idle conditions and the third pump is activated to pump the excess fuel pumped by the second pump toward the second pump.