Pressure compensation control of a fixed displacement pump in a pumping and metering system and associated method

A method of operating a fuel system comprising:

• providing a pump unit that includes first and second pumps, at least one of the pumps being a fixed displacement pump to supply pressurized flow;
• providing a fuel control assembly that receives flow from the pump unit, the fuel control assembly including at least one metering valve and at least one throttling valve;
• monitoring pressure differential across the throttling valve wherein the monitoring step includes receiving a first signal from downstream of the metering valve;
• and
• controlling operation of the pump unit including using a bypass valve that selectively alters operation of the fixed displacement pump in response to the pressure differential.

A fuel system comprising:

• a pump unit that supplies pressurized flow, the pump unit includes a fixed displacement pump;
• a fuel control assembly receiving flow from the pump unit, the fuel control assembly including at least one metering valve and at least one throttling valve;
• and
• a control for the fixed displacement pump including a bypass valve that selectively alters operation of the fixed displacement pump in response to receiving first and second signals indicative of a pressure differential across at least the throttling valve, wherein the first signal is received from downstream of the metering valve.

A method of operating a fuel system comprising:

• providing a pump unit that includes a fixed displacement pump to supply pressurized flow;
• providing a fuel control assembly that receives flow from the pump unit, the fuel control assembly including at least one metering valve and at least one throttling valve;
• monitoring pressure differential across the throttling valve, or across the throttling valve and metering valve combination, wherein the monitoring step includes receiving a first signal from downstream of the metering valve;
• and
• controlling operation of the pump unit including using a bypass valve that selectively alters operation of the fixed displacement pump in response to the pressure differential.