Hydraulic fluid warm-up

Patent metadata

Field	Value
Publication number	US-9340950-B2
Application number	US-201313793795-A
Country	US
Kind code	B2
Filing date	Mar 11, 2013
Priority date	Jan 8, 2013
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A work vehicle including a hydraulic circuit having a cooled return line with a cooler, a bypass return line that bypasses the cooler on the cooled return line, and a controller that electronically controls the flow of hydraulic fluid between the cooled return line and the bypass return line.

First claim

What is claimed is:

1. A work vehicle including:
a chassis;
at least one traction device supporting the chassis;
at least one hydraulic actuator coupled to the chassis;
a hydraulic circuit configured to operate the at least one hydraulic actuator and to selectively effect initial warm-up of a source of hydraulic fluid, the hydraulic circuit including:
a source of hydraulic fluid;
a delivery device in fluid communication with the source of hydraulic fluid;
a flow control valve coupled in fluid communication with the delivery device and with the at least one hydraulic actuator and being operable to selectively deliver hydraulic fluid to, and to receive return fluid from, the at least one hydraulic actuator;
a return line coupled for receiving return fluid from the flow control valve and for returning the return fluid to the source of hydraulic fluid;
the return line being branched into a first return line branch and a second return line branch;
said first return line branch including a normally closed, pressure responsive first flow control device and a cooler connected in series with each other, the first flow control device allowing the hydraulic return fluid to travel along the first return line branch when a pressure in the first return line branch immediately upstream of the first control device exceeds a cracking pressure of the first flow control device;
said second return line branch bypassing the first flow control device and the cooler on the first return line branch, the second return line branch including a pressure responsive second flow control device, the second flow control device allowing the hydraulic fluid to travel along the second return line branch when the return fluid immediately upstream of the second flow control device exceeds a second cracking pressure of the second flow control device; and
a controller in communication with at least one of the first and second flow control devices and being operable when cooling of the return fluid is not desired to adjust at least one of the first and second cracking pressures to cause the first cracking pressure to be relatively higher than the second cracking pressure so that the return fluid flows through the second return line branch to the hydraulic fluid source by way of the second flow control device and bypasses the first flow control device and the cooler.

2. The work vehicle of claim 1 , wherein an electrically responsive regulating valve is in fluid communication with at least one of the first and second flow control devices and is operable for respectively effecting first and second conditions respectively routing a pilot pressure and from and to the at least one of the first and second flow control devices for respectively increasing and decreasing the cracking pressure of the at least one of the first and second flow control devices; and
said controller being in electrical communication with the electrically responsive regulating valve for selectively energizing the electrically responsive regulating valve for establishing said first and second conditions in said at least one of the first and second flow control devices.

3. The work vehicle of claim 1 , wherein the controller automatically adjusts at least one of the first and second cracking pressures to prevent the return flow from normally flowing through the cooler based on at least one of:
a temperature input representing a temperature of hydraulic fluid being supplied by the delivery device;
a time input representing the time elapsed since initially starting operation of the delivery device; and
a manual input from an operator of the work vehicle including at least one of a predetermined temperature input and a predetermined warm-up time.

4. The work vehicle of claim 3 , wherein the controller adjusts at least one of the first and second cracking pressures to:
direct the hydraulic return fluid along the first return line branch when the temperature input indicates that the hydraulic fluid is at or above the predetermined temperature; and
direct the hydraulic fluid along the second return line branch when the temperature input indicates that the hydraulic fluid is below the predetermined temperature.

5. The work vehicle of claim 4 , wherein the predetermined temperature is at least about 40° C.

6. The work vehicle of claim 1 , wherein the first flow control device includes a first check valve having the first cracking pressure, and the second flow control device includes a second check valve having the second cracking pressure.

7. The work vehicle of claim 6 , further including an electrically responsive regulating valve in electrical communication with the controller and in fluid communication with the first check valve, the regulating valve having:
a de-energized first, neutral position that allows pilot pressure to escape from the first check valve; and
an energized second position that directs pilot pressure into the first check valve to increase the first cracking pressure of the first check valve.

8. The work vehicle of claim 7 , wherein the regulating valve is a proportional valve that is adjustable to at least one energized, intermediate position between the first and second positions.

9. The work vehicle of claim 1 , wherein the second cracking pressure of the second flow control device normally exceeds the first cracking pressure of the first flow control device, such that hydraulic return fluid normally travels through the first flow control device and the cooler on the first return line.

10. The work vehicle of claim 9 , wherein, during initial operation of the work vehicle, the controller at least one of:
increases the first cracking pressure of the first flow control device above the second cracking pressure of the second flow control device; and
decreases the second cracking pressure of the second flow control device below the first cracking pressure of the first flow control device;
wherein the hydraulic return fluid travels through the second flow control device on the second return line while bypassing the cooler on the first return line.

11. The work vehicle of claim 1 , wherein:
the first flow control device includes at least one of a check valve, a pressure relief valve, and an orifice; and
the second flow control device includes at least one of a check valve, a pressure relief valve, and an orifice.

12. The work vehicle of claim 1 , wherein the controller comprises an on-off switch.

13. A work vehicle including:
a chassis;
at least one traction device supporting the chassis;
at least one hydraulic actuator coupled to the chassis;
at least one hydraulic control valve:
a hydraulic circuit configured to operate the at least one hydraulic actuator, the hydraulic circuit including:
a source of hydraulic fluid;
a delivery device in fluid communication with the source and with the at least one hydraulic control valve to deliver the hydraulic fluid to the at least one hydraulic actuator via the at least one hydraulic control valve;
a branched return line extending from the at least one control valve to the source, the branched return line comprising
a first return line branch connected to the source and including a cooler;
a second return line branch connected to the source;
a restriction controlling arrangement associated with the first return line branch and with the second return line branch and including an electrically responsive device operable for adjusting a relative restriction to return fluid flow through the first and second return line branches; and
an electronic controller being connected to said electrically responsive device for electronically adjusti

Assignees

• Deere & Co

Inventors

• Mcwethy Erik W

Classifications

• F15B2211/6343

  representing a temperature · CPC title

• F15B2211/611

  Diverting circuits, e.g. for cooling or filtering · CPC title

• F15B2211/41563

  being connected to a pressure source and a return line · CPC title

• F15B2211/62

  Cooling or heating means · CPC title

• F01P2060/08

  Cabin heater · CPC title