Method and apparatus for controlling a fluid actuated system
AssigneeCaterpillar Inc.
InventorsJames R. Blass, Dennis H. Gibson, Ryan P. Michels
Life of this patent
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Abstract
The present invention relates to an improved fluid actuated system, such as those used in hydraulically actuated fuel injectors of an internal combustion engine. A fluid pump supplies hydraulic fluid to a high pressure rail that in turn supplies the fuel injectors with high pressure fluid. Pump output control is provided by an actuator and an electronic control module. A position sensor provides data related to actuator position to the electronic control module. Pump control parameters are determined by the electronic control module, based on fluid pressure, engine operating conditions and actuator position.
Claims16
A fluid actuated system comprising:
- a variable delivery pump having a piston and a high pressure conduit, an actuator having a plunger, moveable between a first position at which a maximum fluid output being delivered and a second position at which a minimum fluid output being delivered, a position sensor connected to said pump and being adapted to deliver a signal relative to the position of the actuator between said first and second position;
- a fluid pressure sensor connected to said high pressure conduit and being adapted to deliver a pressure signal representative of a fluid pressure in said high pressure conduit;
- and
- an electronic control module connected to receive said pressure signal and said position signal, and delivering a first directional move signal in response to said pressure signal being below a first predetermined value and said actuator being at a location between said first and second positions, said actuator receiving said first directional move signal and moving said plunger in a first direction toward maximum fluid output.
A method of controlling a fluid pump, said fluid pump having an actuator, said actuator being moveable between a first position at which said pump delivering a maximum fluid output, and a second position at which said pump delivering a minimum fluid output, said method including the steps of:
- sensing the pressure of said fluid output and delivering a pressure signal;
- sensing the position of said actuator and delivering a first position signal related to a maximum pump output and second position signal related to a minimum pump output;
- and
- delivering first directional move signal in response to said pressure signal being below a predetermined value and said position signal being between said first and second position, and delivering a second directional move signal in response to said pressure signal being above said predetermined value and said position signal being between said first and second position.
A method of estimating the viscosity of a fluid in a hydraulically actuated system having a fluid delivery pump comprising the steps of:
- sensing a first position of a moveable device within said fluid and delivering a responsive position signal;
- delivering a first directional move signal to said moveable device and sensing a second position at a predetermined time;
- calculating a speed of said moveable device;
- and
- determining the viscosity of said fluid based upon said calculated speed.
Dependencies are inferred from the claim text.