Variable displacement piston pump with electronic control unit to provide direct metering control

Patent metadata

Field	Value
Publication number	US-2023204029-A1
Application number	US-202117562214-A
Country	US
Kind code	A1
Filing date	Dec 27, 2021
Priority date	Dec 27, 2021
Publication date	Jun 29, 2023
Grant date	—

Abstract

A variable displacement piston pump, having: a housing, a pivot assembly to pivot between minimal and maximum pivot angles; a pump cover defining an actuator bore with an actuator piston, an actuator arm extending from the actuator piston to the pivot assembly; and an electronic control unit (ECU) coupled to the pump, the ECU having: a pump controller, a linear variable differential transducer (LVDT) coupled to the pump controller and the actuator piston, and an electrohydraulic solenoid valve (EHSV) coupled to the pump controller, the ECU is configured to: determine a pivot differential for the pivot assembly between a target pivot angle and a current pivot angle; determine a position differential for the actuator piston, corresponding to the pivot differential of the pivot assembly; control the EHSV to move the actuator piston by the position differential; and determine, from the LVDT, that the actuator piston moved by the position differential.

First claim

What is claimed is:

1 . A direct metering control variable displacement piston pump, comprising:
a pump housing defining a housing cavity, a pivot assembly configured to pivot within the pump housing between minimal and maximum pivot angles; a pump cover disposed against the pump housing, the pump cover defining an actuator bore, an actuator piston in the actuator bore, an actuator arm extending from the actuator piston to the pivot assembly; and an electronic control unit (ECU) operationally coupled to the pump, the ECU comprising: a pump controller, a linear variable differential transducer (LVDT) operationally coupled to the pump controller and the actuator piston, and an electrohydraulic solenoid valve (EHSV) operationally coupled to the pump controller, wherein the ECU is configured to:
determine a pivot differential for the pivot assembly between a target pivot angle and a current pivot angle;
determine a position differential for the actuator piston, corresponding to the pivot differential of the pivot assembly;
control the EHSV to thereby move the actuator piston by the position differential; and
determine, from the LVDT, that the actuator piston moved by the position differential.

2 . The pump of claim 1 , wherein
the ECU is further configured to:
monitor to identify pressure perturbations in the pump resulting from pressure changes to a fluid flow; and
react to pressure perturbations in the pump with controlled metered movement of the actuator piston.

3 . The pump of claim 2 , wherein:
the pump cover further includes:
an inlet port and an inlet passage that extends from the inlet port to the pump housing;
an outlet port and an outlet passage that extends from the outlet port to the EHSV and to the pump housing;
a return passage that extends from the EHSV to the pump housing; and
a coupling passage that extends between the actuator bore and the EHSV.

4 . The pump of claim 3 , further comprising:
sensors operationally connected to the ECU, the sensors including:
an inlet pressure sensor, disposed in the return passage, configured to sense pump inlet pressure; and
an outlet pressure sensor, disposed in the outlet passage, configured to sense pump outlet pressure,
wherein the ECU is configured to monitor to identify pressure perturbations in the pump resulting from pressure changes to the fluid flow by sensed pressure fluctuations at the inlet and outlet during movement of the pivot assembly.

5 . The pump of claim 4 , wherein
the actuator bore defines a top end and a bottom end, wherein the bottom end is disposed against the pump housing, and the pump further comprises:
a biasing member configured to bias the pivot assembly toward a maximum pivot angle;
an actuator pressure sensor, disposed in the coupling passage, configured to sense pressure at the actuator piston,
wherein the ECU is configured to control the EHSV by:
increasing pressure against the actuator piston to move the actuator piston toward the bottom end of the actuator bore, countering a biasing force that biases the pivot assembly toward the maximum pivot angle; or
reducing pressure against the actuator piston, thereby enabling the biasing force to move the pivot assembly toward the maximum pivot angle, and thereby moving the actuator piston toward the bottom end of the actuator bore.

6 . The pump of claim 5 , wherein
the pump is configured so that: when the actuator piston is disposed at the top end of the actuator bore, the pivot assembly is disposed at the maximum pivot angle; and when the actuator piston is disposed at the bottom end of the actuator bore, the pivot assembly is disposed at a minimum pivot angle.

7 . The pump of claim 1 , further comprising:
a pivot base defining a pivot base cavity, and a coupler shaft seated in the pivot base cavity, the coupler shaft defines piston seats and a coupler shaft bore; a cylinder barrel configured to slide within the pivot assembly, the cylinder barrel defines piston bores and a universal shaft bore; and pistons that extend from the piston seats in the coupler shaft into the piston bores in the cylinder barrel, and a universal shaft that extends from the coupler shaft bore in the coupler shaft to the universal shaft bore in the cylinder barrel.

8 . The pump of claim 1 , wherein
the pump is a bent axis pump.

9 . A gas turbine engine, comprising:
a fuel supply; the pump of claim 1 ; an engine pressure regulator configured to receive fuel from the pump; and an engine controller operationally coupled to the ECU and configured to communicate parameters to the ECU indicative of the target pivot angle for the pivot assembly.

10 . The engine of claim 9 , wherein
the pressure regulator is configured to direct a pressure controlled fuel flow to the engine.

11 . A method of controlling a variable displacement piston pump, the method including a:
determining, via a pump electronic control unit (ECU) that is operationally coupled to the pump, a pivot differential for a pivot assembly of the pump between a target pivot angle and a current pivot angle; determining, by the ECU, a position differential for an actuator piston of the pump, corresponding to the pivot differential for the pivot assembly; controlling an electrohydraulic solenoid valve (EHSV) of the ECU, to thereby move the actuator piston by the position differential; and determine, by a linear variable differential transducer (LVDT) of the ECU, that the actuator piston moved by the position differential.

12 . The method of claim 11 , further comprising
monitoring to identify pressure perturbations in the pump resulting from pressure changes to a fluid flow; and reacting to pressure perturbations in the pump with controlled, metered movement of the actuator piston.

13 . The method of claim 12 , further comprising:
sensing pump inlet pressure via an inlet pressure sensor operationally coupled to the ECU and located in a return passage that is fluidly coupled to the EHSV; sensing pump outlet pressure via an outlet pressure sensor operationally coupled to the ECU and located in an outlet passage of the pump; monitoring to identify pressure perturbations in the pump resulting from pressure changes to the fluid flow by sensed pressure fluctuations at the inlet and outlet during movement of the pivot assembly.

14 . The method of claim 11 , further comprising
sensing pressure at an actuator bore via an actuator pressure sensor operationally coupled to the ECU and located in a coupling passage between the actuator bore and the EHSV, and wherein controlling the EHSV includes:
increasing pressure against the actuator piston to move the actuator piston toward a bottom end of the actuator bore, countering a biasing force that biases the pivot assembly toward a maximum pivot angle; or
reducing pressure against the actuator piston, thereby enabling the biasing force to move the pivot assembly toward the maximum pivot angle, and thereby moving the actuator piston toward the bottom end of the actuator bore; and
determining a pressure required to move the actuator piston toward the bottom end of the actuator bore as a difference between and pressure in the actuator bore.

15 . The method of claim 14 , further comprising
the ECU causing movement of the actuator piston between: a top end of the actuator bore to position the pivot assembly at the maximum pivot angle; and the bottom end of the actuator bore to position the pivot assembly at a minimum pivot angle.

16 . The method of claim 11 , further comprising:
the ECU

Assignees

• Hamilton Sundstrand Corp

Inventors

• Ni Weishun Willaim
• Goy Edward W
• Harder Benjamin T
• Shoemaker Mark W

Classifications

• F04B49/12

  by varying the length of stroke of the working members · CPC title

• F04B49/065

  and making use of computers · CPC title

• F02C9/30 Primary

  characterised by variable fuel pump output · CPC title

• F04B2205/02

  Pressure in the inlet chamber · CPC title

• F04B1/328 Primary

  by changing the inclination of the axis of the cylinder barrel relative to the swash plate · CPC title