Multiple Element Firing Strategy for Cryogenic Pump

Patent metadata

Field	Value
Publication number	US-2016377041-A1
Application number	US-201514753613-A
Country	US
Kind code	A1
Filing date	Jun 29, 2015
Priority date	Jun 29, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

A pump has a plurality of pumping elements, each being independently responsive to an actuation signal from a controller. The controller is programmed to maintain a desired pressure at the pump discharge, monitor the fluid pressure at the pump discharge, compare the fluid pressure with the desired fluid pressure to determine a pressure error, provide commands to sequentially actuate the pumping elements when the pressure error is within a threshold range, and provide commands to actuate more than one of the plurality of pumping elements simultaneously, such that more than one pumped amounts of fluid are delivered simultaneously at the pump discharge, when the pressure error droops outside of the threshold range.

First claim

We claim:

1 . A fluid system, comprising:
a pump having a plurality of pumping elements, each of the plurality of pumping elements being independently responsive to a corresponding actuation signal to perform a pumping stroke that delivers a pumped amount of fluid at a pump discharge; a pressure sensor disposed to monitor a fluid pressure at the pump discharge and provide a pressure signal; an electronic controller associated with the pump and the pressure sensor, the electronic controller disposed to receive the pressure signal and provide the corresponding actuation signal to each of the plurality of pumping elements, the electronic controller being further programmed to maintain a desired pressure at the pump discharge, the electronic controller being programmed to:
monitor the fluid pressure provided by the pressure sensor;
compare the fluid pressure with the desired pressure to determine a pressure error;
provide commands to sequentially actuate the plurality of pumping elements when the pressure error is within a threshold range; and
provide commands to actuate more than one of the plurality of pumping elements simultaneously, such that more than one pumped amounts of fluid are delivered simultaneously at the pump discharge, when the pressure error droops outside of the threshold range.

2 . The fluid system of claim 1 , wherein a program of the electronic controller for providing commands to sequentially actuate the plurality of pumping elements includes a command signal providing a frequency of sequential actuation of the plurality of pumping elements.

3 . The fluid system of claim 2 , wherein the command signal is further based on a parameter indicative of a rate of consumption of a fluid at the pump discharge by a consumer.

4 . The fluid system of claim 3 , wherein the consumer is an engine and wherein the fluid is fuel drawn from a fuel tank by the pump.

5 . The fluid system of claim 4 , wherein the fuel is liquefied natural gas (LNG).

6 . The fluid system of claim 1 , wherein the electronic controller is further programmed to correct the commands to sequentially actuate the plurality of pumping elements and the commands to actuate more than one of the plurality of pumping elements based on an indication of a temperature of a fluid at the pump discharge.

7 . The fluid system of claim 1 , wherein the electronic controller is further programmed to periodically command two or more of the plurality of pumping elements to actuate simultaneously, even when the pressure error is within the threshold range, such that a resolution of a pressure rise at the pump discharge is increased, and wherein the electronic controller is further programmed to calculate a stroke time when the pressure rise at a pump discharge pressure is increased.

8 . A method for operating a pump, comprising:
providing a plurality of pumping elements, each being independently actuated in response to an actuation signal from a controller; receiving and monitoring at the controller a plurality of engine operating parameters including a pressure signal that is directly or indirectly indicative of a pump discharge pressure at a pump discharge; comparing the pump discharge pressure with a desired discharge pressure; providing a command to sequentially actuate pumping elements at a desired frequency; determining whether the pump is capable of providing a desired pressure within a desired time; and providing a command to non-sequentially actuate more than one pumping element simultaneously when an indication is present that sequential pumping element actuations will be insufficient to achieve the desired discharge pressure of the pump.

9 . The method of claim 8 , wherein determining whether the pump is capable of providing the desired pressure is accomplished by monitoring a pressure droop in the pressure signal, comparing the pressure droop with a threshold range, and providing an indication signal of a need to actuate more than one of the plurality of pumping elements at one time when the pressure droop falls outside of the threshold range.

10 . The method of claim 8 , further comprising resuming sequential pumping element actuation when the pump discharge pressure re-enters within a predetermined range around the desired discharge pressure.

11 . The method of claim 8 , wherein providing a command to sequentially actuate the pumping elements includes sequentially actuating the pumping elements at the desired frequency.

12 . The method of claim 11 , wherein the desired frequency is based on a parameter indicative of a rate of consumption of a fluid at the pump discharge by a consumer.

13 . The method of claim 12 , wherein the consumer is an engine and wherein the fluid is fuel drawn from a fuel tank by the pump.

14 . The method of claim 13 , wherein the fuel is liquefied natural gas (LNG).

15 . The method of claim 8 , further comprising correcting the commands to sequentially actuate the pumping elements and the commands based on a temperature of a fluid at the pump discharge.

16 . The method of claim 8 , further comprising periodically commanding two or more of the pumping elements to actuate simultaneously to increase a pressure rise at the pump discharge, and calculating a stroke time when the pressure rise at the pump discharge pressure is increased.

17 . A fuel system for an engine, comprising:
a cryogenic fluid storage tank containing a fuel; a pump having a plurality of pumping elements, each of the plurality of pumping elements being independently responsive to a corresponding actuation signal to perform a pumping stroke that delivers a pumped amount of fuel at a pump discharge; a pressure sensor disposed to monitor a fluid pressure at the pump discharge and provide a pressure signal; an electronic controller associated with the pump and the pressure sensor, the electronic controller disposed to receive the pressure signal and provide the corresponding actuation signal to each of the plurality of pumping elements, the electronic controller being further programmed to maintain a desired pressure at the pump discharge, the electronic controller being programmed to:
monitor the fluid pressure provided by the pressure sensor;
compare the fluid pressure with the desired pressure to determine a pressure error;
provide commands to sequentially actuate the plurality of pumping elements when the pressure error is within a threshold range; and
provide commands to actuate more than one of the plurality of pumping elements simultaneously, such that more than one pumped amounts of fluid are delivered simultaneously at the pump discharge, when the pressure error droops outside of the threshold range.

18 . The fuel system of claim 17 , further comprising the engine, wherein the engine consumes the fuel provided by the pump thus tending to decrease a discharge pressure of the pump.

19 . The fuel system of claim 17 , wherein the electronic controller is further programmed to correct the commands to sequentially actuate the plurality of pumping elements and the commands to actuate more than one of the plurality of pumping elements based on an indication of a temperature of the fuel at the pump discharge.

20 . The fuel system of claim 17 , wherein the electronic controller is further programmed to periodically command two or more of the plurality of pumping elements to actuate simultaneously, even when the pressure error is within the threshold range, such that a resolution of a pressure rise at the pump

Assignees

• Caterpillar Inc

Inventors

• Steffen Joshua W
• Bean Sunil J

Classifications

• F02M59/10 Primary

  characterised by the piston-drive · CPC title

• F02D19/0644 Primary

  the gaseous fuel being hydrogen, ammonia or carbon monoxide · CPC title

• F02D19/0684

  High pressure fuel injection systems; Details on pumps, rails or the arrangement of valves in the fuel supply and return systems · CPC title

• F02D19/0694

  operating with a plurality of fuels · CPC title

• F02D2200/0602

  Fuel pressure · CPC title