# US 2014/0150415 A1 · Energy Recovery Hydraulic System > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0150415 A1 - Document ID: US20140150415A1 - Status: Published application - Kind: A1 - Application number: 13/693,509 - Filed: 2012-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: Caterpillar Inc. - Applicants: Caterpillar Inc. - Inventors: Jiao Zhang; Gang Wen; Pengfei Ma; Tonglin Shang; Dayao Chen; Bryan J. Hillman; Vickram Murugesan - Web page: https://patentgrep.com/patent/US20140150415A1 ## CPC - F04B 7/02: the valving being fluid-actuated - F04B 49/002: {Hydraulic systems to change the pump delivery} - F15B 1/024: {used as a supplementary power source, e.g. to store energy in idle periods to balance pump load} - F15B 21/14: Energy-recuperation means - F15B 2211/20507: Type of prime mover - F15B 2211/212: the pressure sources being accumulators - F15B 2211/30565: having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve - F15B 2211/3058: having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode - F15B 2211/6306: representing a pressure - F15B 2211/6313: the pressure being a load pressure - F15B 2211/7053: Double-acting output members - F15B 2211/88: Control measures for saving energy - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract A method and system for accumulating and using recovered hydraulic energy that includes a hydraulic actuator and a pump configured to supply pressurized fluid to the hydraulic actuator. An energy recovery system includes a hydraulic motor, a charge valve and an accumulator configured to store fluid from the hydraulic actuator. The charge valve is operatively connected between the hydraulic actuator and the accumulator and between the accumulator and the hydraulic motor and is configured to place the hydraulic actuator in fluid communication with the accumulator and to place the accumulator in fluid communication with the hydraulic motor. A directional valve is operatively connected between the pump and the hydraulic actuator. The directional valve is configured to place the pump in fluid communication with the hydraulic actuator and to direct the flow of hydraulic fluid exiting the hydraulic actuator to the charge valve in an energy recovery mode. ## Claims ### Claim 1 A hydraulic system comprising: a hydraulic actuator; a pump configured to supply pressurized fluid to the hydraulic actuator; and an energy recovery system including a hydraulic motor, a charge valve and an accumulator configured to store fluid from the hydraulic actuator, the charge valve being operatively connected between the hydraulic actuator and the accumulator and between the accumulator and the hydraulic motor and being configured to selectively place the hydraulic actuator in fluid communication with the accumulator and to selectively place the accumulator in fluid communication with the hydraulic motor; and a directional valve operatively connected between the pump and the hydraulic actuator, the directional valve being configured to selectively place the pump in fluid communication with the hydraulic actuator and being configured to selectively direct the flow of hydraulic fluid exiting the hydraulic actuator to the charge valve in an energy recovery mode. ### Claim 2 (depends on 1) The hydraulic system according to claim 1, wherein the directional valve is movable between a first position and a second position and wherein in the first position the directional valve places the pump in fluid communication with a first chamber of the hydraulic actuator and places a second chamber of the hydraulic actuator in communication with a tank and wherein in the second position the directional valve places the pump in fluid communication with the second chamber of the hydraulic actuator and places the first chamber of the hydraulic actuator in communication with the tank. ### Claim 3 (depends on 2) The hydraulic system according to claim 2, wherein the directional valve is movable into a third position in which the directional valve places the pump in fluid communication with the second chamber of the hydraulic actuator and places the first chamber of the hydraulic actuator in communication with the charge valve. ### Claim 4 (depends on 3) The hydraulic system according to claim 3, wherein the charge valve is movable between a first position and a second position and wherein in the first position the charge valve places the accumulator in fluid communication with the hydraulic motor. ### Claim 5 (depends on 4) The hydraulic system according to claim 4, wherein in the second position the charge valve places the first chamber of the hydraulic actuator in communication with the accumulator. ### Claim 6 (depends on 5) The hydraulic system according to claim 5, wherein the charge valve is movable into a third position in which the charge valve places the first chamber of the hydraulic actuator in communication with the accumulator and places the accumulator in fluid communication with the hydraulic motor. ### Claim 7 (depends on 1) The hydraulic system according to claim 1, further including a power source operatively connected to the pump and wherein the hydraulic motor is operatively connected to the power source. ### Claim 8 (depends on 1) The hydraulic system according to claim 1, further including a regeneration valve for selectively placing a first chamber of the hydraulic actuator in communication with a second chamber of the hydraulic actuator. ### Claim 9 A machine comprising: a work implement; a hydraulic system configured to actuate the work implement, the hydraulic system including: a hydraulic actuator having a first end chamber and a second end chamber; a pump configured to supply pressurized fluid to the hydraulic actuator; and an energy recovery system including a hydraulic motor, a charge valve and an accumulator configured to store fluid from the hydraulic actuator, the charge valve being operatively connected between the hydraulic actuator and the accumulator and between the accumulator and the hydraulic motor and being configured to selectively place the hydraulic actuator in fluid communication with the accumulator and to selectively place the accumulator in fluid communication with the hydraulic motor; and a directional valve operatively connected between the pump and the hydraulic actuator, the directional valve being configured to selectively place the pump in fluid communication with the first chamber of the hydraulic actuator and to selectively place the pump in fluid communication with the second chamber of the hydraulic actuator, the directional valve being configured to selectively direct the flow of hydraulic fluid exiting the hydraulic actuator to the charge valve. ### Claim 10 (depends on 9) The machine according to claim 9, wherein the directional valve is movable between a first position and a second position and wherein in the first position the directional valve places the pump in fluid communication with a first chamber of the hydraulic actuator and places a second chamber of the hydraulic actuator in communication with a tank and wherein in the second position the directional valve places the pump in fluid communication with the second chamber of the hydraulic actuator and places the first chamber of the hydraulic actuator in communication with the tank. ### Claim 11 (depends on 10) The machine according to claim 10, wherein the directional valve is movable into a third position in which the directional valve places the pump in fluid communication with the second chamber of the hydraulic actuator and places the first chamber of the hydraulic actuator in communication with the charge valve. ### Claim 12 (depends on 11) The machine according to claim 11, wherein the charge valve is movable between a first position and a second position and wherein in the first position the charge valve places the accumulator in fluid communication with the hydraulic motor. ### Claim 13 (depends on 12) The machine according to claim 12, wherein in the second position the charge valve places the first chamber of the hydraulic actuator in communication with the accumulator. ### Claim 14 (depends on 13) The machine according to claim 13, wherein the charge valve is movable into a third position in which the charge valve places the first chamber of the hydraulic actuator in communication with the accumulator and places the accumulator in fluid communication with the hydraulic motor. ### Claim 15 (depends on 9) The machine according to claim 9, further including a power source operatively connected to the pump and wherein the hydraulic motor is operatively connected to the power source. ### Claim 16 (depends on 9) The machine according to claim 9, further including a regeneration valve for selectively placing a first chamber of the hydraulic actuator in communication with a second chamber of the hydraulic actuator. ### Claim 17 A method for recovering energy in a hydraulic circuit including a pump and a hydraulic cylinder, the method comprising: directing fluid exiting the hydraulic actuator to an accumulator using a directional valve and a charge valve in a first operating condition; directing fluid from the hydraulic actuator to the accumulator and to a hydraulic motor using the directional valve and the charge valve in a second operating condition; and directing fluid from the accumulator to the hydraulic motor using the charge valve in a third operating condition. ### Claim 18 (depends on 17) The method according to claim 17, further including the step of blocking hydraulic fluid from reaching the accumulator using the directional valve in a fourth operating condition. ### Claim 19 (depends on 17) The method according to claim 17, wherein the directional valve and the charge valve are spool valves. ### Claim 20 (depends on 17) The method according to claim 17, further including the step of selectively placing a first chamber of the hydraulic actuator in communication with a second chamber of the hydraulic actuator with a regeneration valve.