Integration of swing energy recovery and engine anti-idling systems

Patent metadata

Field	Value
Publication number	US-9951795-B2
Application number	US-201514668671-A
Country	US
Kind code	B2
Filing date	Mar 25, 2015
Priority date	Mar 25, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

Engine anti-idling and restart may be implemented in a machine having a power source, a movable work tool, a pump driven by the power source, an actuator receiving fluid from the pump and moving the work tool, a high-pressure fluid reservoir, and an assist motor operatively connected to the power source. Engine restart may include detecting operator input to start the power source, and fluidly connecting the fluid reservoir to the assist motor to assist in starting the power source in response to detecting the operator input. Prior to shutting down the power source during anti-idling, fluid from the pump may be input to the assist motor, pressurized and communicated to the high-pressure fluid reservoir in response to determining that idle condition exists and a reservoir charge pressure is less than a reservoir minimum restart pressure needed to restart the power source.

First claim

What is claimed is:

1. A hydraulic control system for a machine having a power source, comprising:
a work tool movable through a range of motion;
a pump driven by the power source to pressurize fluid;
an actuator configured to receive pressurized fluid from the pump and move the work tool;
a first accumulator selectively fluidly connected to the pump and to the actuator;
an assist motor operatively connected to the power source;
a discharge valve having a normally closed position and an open position, the discharge valve positioned to selectively fluidly connect the first accumulator to the assist motor;
a controller operatively connected to the discharge valve, wherein:
the controller is configured to detect operator input to start the power source, and
the controller is configured to cause the discharge valve to move to the open position to fluidly connect the first accumulator to the assist motor to assist in starting the power source in response to detecting the operator input to start the power source; and

a bypass valve operatively connected to the controller and having a normally open position and a closed position, the bypass valve positioned to selectively fluidly connect an assist motor outlet of the assist motor to a low-pressure fluid reservoir of the machine, wherein the controller is operatively connected to the power source, and wherein:
the controller is configured to determine an idle condition for stopping the power source due to inactivity of the machine;
the controller is configured to determine a first accumulator charge pressure of the first accumulator; and
the controller is configured to cause the bypass valve to move to the closed position such that pressurized fluid output by the assist motor is communicated to the first accumulator, and to cause pressurized fluid output by the pump to be communicated and input to the assist motor, in response to determining that the machine is in the idle condition and the first accumulator charge pressure is less than a first accumulator minimum restart pressure.

2. The hydraulic control system of claim 1 , comprising a charge valve having a normally closed position, an open position, and a charge set pressure, the charge valve being positioned to selectively fluidly connect the actuator to the first accumulator, wherein the charge valve moves from the normally closed position to the open position and fluidly connects the actuator to the first accumulator when an actuator fluid pressure communicated to the charge valve from the actuator is greater than the charge set pressure.

3. The hydraulic control system of claim 1 , wherein the actuator comprises a swing motor configured to swing the work tool about a vertical axis.

4. The hydraulic control system of claim 3 , wherein the machine includes a boom hybrid circuit for raising and lowering the work tool, and wherein the boom hybrid circuit is selectively fluidly connected to the assist motor to provide pressurized fluid thereto.

5. The hydraulic control system of claim 1 , wherein:
the controller is configured to cause the power source to shut down in response to determining that the machine is in the idle condition and the first accumulator charge pressure is greater than a first accumulator minimum restart pressure.

6. The hydraulic control system of claim 1 , wherein the controller is operatively connected to the pump, and wherein the controller is configured to cause the pump to increase an output pressurized fluid flow rate in response to determining that the machine is in the idle condition and the first accumulator charge pressure is less than an accelerated restart charge pressure.

7. The hydraulic control system of claim 1 , comprising a flow control device operatively connected to the controller and having a normally open position and a closed position, the flow control device positioned to selectively fluidly connect a pump outlet of the pump to an assist motor inlet of the assist motor, wherein the controller is configured to cause the flow control device to move to the normally open position in response to determining that the machine is in the idle condition and the first accumulator charge pressure is less than the first accumulator minimum restart pressure.

8. The hydraulic control system of claim 7 , wherein the flow control device comprises a variable orifice.

9. The hydraulic control system of claim 1 , wherein the controller is operatively connected to the power source, and wherein the controller is configured to cause the power source to shut down in response to determining that the machine is in the idle condition and the first accumulator charge pressure is greater than the first accumulator minimum restart pressure.

10. A method for operating a machine having a power source, a work tool movable through a range of motion, a pump driven by the power source to pressurize fluid, an actuator configured to receive pressurized fluid from the pump and move the work tool, a high-pressure fluid reservoir, and an assist motor operatively connected to the power source, the method for operating a machine comprising:
detecting operator input to start the power source;
fluidly connecting the high-pressure fluid reservoir to the assist motor to assist in starting the power source in response to detecting operator input to start the power source;
determining an idle condition for stopping the power source due to inactivity of the machine;
determining a reservoir charge pressure of the high-pressure fluid reservoir; and
communicating pressurized fluid output by the assist motor to the high-pressure fluid reservoir, and outputting pressurized fluid from the pump to the assist motor, in response to determining that the machine is in the idle condition and the reservoir charge pressure is less than a reservoir minimum restart pressure.

11. The method for operating a machine of claim 10 , wherein the machine includes a boom hybrid circuit for raising and lowering the work tool, the method for operating a machine comprising selectively fluidly connecting the boom hybrid circuit to the assist motor to provide pressurized fluid thereto.

12. The method for operating a machine of claim 10 , comprising:
shutting down the power source in response to determining that the machine is in the idle condition and the reservoir charge pressure is greater than a reservoir minimum restart pressure.

13. The method for operating a machine of claim 10 , comprising increasing a pressurized fluid flow rate of pressurized fluid output by the pump in response to determining that the machine is in the idle condition and the reservoir charge pressure is less than an accelerated restart charge pressure.

14. The method for operating a machine of claim 10 , comprising fluidly connecting a pump outlet of the pump to an assist motor inlet of the assist motor in response to determining that the machine is in the idle condition and the reservoir charge pressure is less than the reservoir minimum restart pressure.

15. The method for operating a machine of claim 10 , comprising shutting down the power source in response to determining that the machine is in the idle condition and the reservoir charge pressure is greater than the reservoir minimum restart pressure.

16. A hydraulic control system for a machine having a power source, comprising:
a work tool movable through a range of motion;
a pump driven by the power source to pressurize fluid;
an actuator configured to receive pressurized fluid from the pump and move the work tool;
a first accumulator selectively fluidly connected to the pump and t

Assignees

• Caterpillar Inc

Inventors

• Shang Tonglin
• Ma Pengfei
• Chen Dayao
• Peterson Jeremy
• Morris Emily Anne

Classifications

• F02N2200/10

  said parameters being related to driver demands or status · CPC title

• F15B2211/6313

  the pressure being a load pressure · CPC title

• F15B2211/20569

  capable of working as pump and motor · CPC title

• F15B21/14

  Energy-recuperation means · CPC title

• F15B2211/6309

  the pressure being a pressure source supply pressure · CPC title