Constant bypass flow controller for a variable displacement pump
AssigneeGoodrich Pump & Engine Control Systems, Inc.
InventorsGeorge L. Bennett, William H. Dalton, Raymond D. Zagranski
Life of this patent
Estimating the term…
Abstract
A fuel metering unit for controlling a variable displacement pump including a main metering valve in fluid communication with the pump for metering an output of the pump, a pressure regulator in fluid communication with the metering valve to create a spill return and a control valve in fluid communication with the pressure regulator and the pump for regulating the spill return flow so the spill return flow is maintained substantially constant at a low level to minimize the heat generated by recirculation by setting a displacement of the pump.
Claims21
A fuel metering unit for controlling a variable displacement pump comprising:
- a metering valve in fluid communication with the pump for metering an output of the variable displacement pump;
- a flow line for creating a spill return flow from an output of the pump;
- a pressure regulator in fluid communication with the flow line for receiving the spill return flow;
- a control valve for regulating the spill return flow to a substantially constant small level to prevent excessive heat generation during recirculation by setting a displacement of the pump;
- and
- an orifice operatively connected to the output of the pressure regulator for creating a pressure differential across the control valve.
A fuel metering unit for controlling a variable displacement pump actuated comprising:
- a servo mechanism for varying an output of the pump;
- a metering valve operatively connected to the output of the pump and an engine such that actuation of the metering valve controls an output of the variable displacement pump so as to schedule fuel flow accurately to the engine;
- a spill return flow line connected between the output of the pump and the metering valve;
- a first regulator operatively connected to the spill return flow line such that a first pressure differential across the first regulator determines an output of the first regulator;
- and
- a second regulator operatively connected to the output of the first regulator and the servo mechanism such that the output of the first regulator is regulated during a steady-state condition, and during a transient condition, a second pressure differential across the second regulator varies to adjust an output of the second regulator to, in turn, adjust the servo echanism to vary the output of the pump such that a subsequent flow in the spill return line is substantially equal to a desired flow.
A fuel metering unit for controlling a variable displacement pump comprising:
- first means in fluid communication with the pump for metering an output of the pump;
- second means in fluid communication with the first means to create a bypass flow for responding to transients;
- third means in fluid communication with the second means and the pump for regulating the bypass flow so bypass flow is substantially constant by variably setting a displacement of the variable displacement pump;
- and
- fourth means for creating fluid communication between the output of the pump and the third means.
A method for maintaining a constant spill return flow in a fuel metering unit that provides fuel to an engine, the method comprising the steps of:
- metering an output of a variable displacement pump;
- creating a spill return flow from the output of the variable displacement pump to allow for quick response when additional fuel is required by the engine;
- regulating the output of the pump with a regulator based upon the spill return flow;
- regulating an output of the fifst regulator with a control valve to maintain the spill return flow substantially constant, wherein an input of the control valve is in fluid communication with the output of the pump through a flow line separate from the spill return flow;
- and
- adjusting a displacement of the pump based upon an output of the control valve.
A fuel metering unit for controlling a variable displacement pump comprising:
- a metering valve in fluid communication with the pump for metering an output of the variable displacement pump;
- a first flow line for creating a spill return flow from an output of the pump;
- a pressure regulator in fluid communication with the flow line for receiving the spill return flow;
- a control valve for regulating the spill return flow to a substantially constant small level to prevent excessive heat generation during recirculation by setting a displacement of the pump;
- and
- a second flow line connected to place the control valve in direct communication with an output of the pump.
A method for maintaining a constant spill return flow in a fuel metering unit that provides fuel to an engine, the method comprising the steps of:
- metering an output of a variable displacement pump;
- creating a spill return flow from the output of the variable displacement pump to allow for quick response when additional fuel is required by the engine;
- regulating the output of the pump with a regulator based upon the spill return flow;
- regulating an output of the regulator with a control valve to maintain the spill return flow substantially constant, the control valve being located in a flow line and having two control inputs;
- adjusting a displacement of the pump based upon an output of the control valve;
- and
- creating a pressure differential between the two control inputs of the control valve to determine the output of the control valve.
Dependencies are inferred from the claim text.