# US 10,119,556 B2 · System having combinable transmission and implement circuits > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,119,556 B2 - Document ID: US10119556B2 - Status: Granted - Kind: B2 - Application number: 14/961,244 - Filed: 2015-12-07 - Published: 2017-06-08 - Granted: 2018-11-06 - Earliest claimed: 2015-12-07 - Assignees: Caterpillar Inc. - Applicants: Caterpillar Inc. - Inventors: Jeremy Todd Peterson; Jeffrey Lee Kuehn; Bryan E. Nelson; Paul Anthony Dvorak - Web page: https://patentgrep.com/patent/US10119556B2 ## CPC - F15B 11/17: using two or more pumps - E02F 3/34: with bucket-arms {, i.e. a pair of arms, e.g. manufacturing processes, form, geometry, material of bucket-arms (with a single arm E02F3/283)} directly pivoted on the frames of tractors or self-propelled machines - E02F 9/2217: {with energy recovery arrangements, e.g. using accumulators, flywheels} - E02F 9/2228: {including an electronic controller} - E02F 9/2242: {including an electronic controller} - E02F 9/2253: {Controlling the travelling speed of vehicles, e.g. adjusting travelling speed according to implement loads, control of hydrostatic transmission} - E02F 9/2289: {Closed circuit} - E02F 9/2292: {Systems with two or more pumps} - E02F 9/2296: {Systems with a variable displacement pump} - F15B 1/024: {used as a supplementary power source, e.g. to store energy in idle periods to balance pump load} - F16H 61/4078: Fluid exchange between hydrostatic circuits and external sources or consumers - F15B 2211/20523: Internal combustion engine - F15B 2211/20546: variable capacity - F15B 2211/20569: capable of working as pump and motor - F15B 2211/20576: with multiple pumps - F15B 2211/212: the pressure sources being accumulators - F15B 2211/27: Directional control by means of the pressure source - F15B 2211/30525: Directional control valves, e.g. 4/3-directional control valve - F15B 2211/3053: In combination with a pressure compensating valve - F15B 2211/3111: the pump port being closed in the centre position, e.g. so-called closed centre - F15B 2211/3144: the positions being continuously variable, e.g. as realised by proportional valves - F15B 2211/31523: being connected to a pressure source and an output member - F15B 2211/351: Flow control by regulating means in feed line, i.e. meter-in control - F15B 2211/455: Control of flow in the feed line, i.e. meter-in control - F15B 2211/613: Feeding circuits - F15B 2211/6346: representing a state of input means, e.g. joystick position - F15B 2211/665: Methods of control using electronic components - F15B 2211/7135: Combinations of output members of different types, e.g. single-acting cylinders with rotary motors - F15B 2211/851: during starting - F15B 2211/88: Control measures for saving energy - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR - E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00) - F16H: GEARING ## Abstract A hydraulic system is disclosed for use with a machine. The hydraulic system may have a closed-loop, meterless hydraulic circuit with a first pump fluidly connected to a first actuator. The hydraulic system may also have a closed-loop, metered hydraulic circuit with a second pump fluidly connected to a second actuator. The hydraulic system may further have a combiner valve configured to selectively direct fluid from the closed-loop metered hydraulic circuit to the closed-loop meterless hydraulic circuit. ## Claims ### Claim 1 A hydraulic system, comprising: a closed-loop, meterless hydraulic circuit having a first pump fluidly connected to a first actuator; a closed-loop, metered hydraulic circuit having a second pump fluidly connected to a second actuator; a combiner valve configured to selectively direct fluid from the closed-loop metered hydraulic circuit to the closed-loop meterless hydraulic circuit; at least one input device configured to receive input indicative of a desire to actively operate the closed-loop, meterless hydraulic circuit and the closed-loop, metered hydraulic circuit; and a controller in communication with the at least one input device and the combiner valve, wherein, when input is received indicative of a desire to transition between active operation of only the first actuator to simultaneous operation of both the first and second actuators, the controller is configured to simultaneously destroke the second pump, close the combiner valve, and decrease a displacement of the first actuator. ### Claim 2 (depends on 1) The hydraulic system of claim 1, wherein the closed-loop, meterless hydraulic circuit is a hydrostatic transmission circuit. ### Claim 3 (depends on 2) The hydraulic system of claim 2, wherein the closed-loop, metered hydraulic circuit is an implement circuit. ### Claim 4 (depends on 1) The hydraulic system of claim 1, wherein, during active operation of only the second actuator, the controller is configured to close the combiner valve and destroke the first pump. ### Claim 5 (depends on 1) The hydraulic system of claim 1, wherein, during active operation of only the first actuator, the controller is configured to open the combiner valve and cause both the first and second pumps to provide pressurized flow to the closed-loop, meterless hydraulic circuit. ### Claim 6 (depends on 1) The hydraulic system of claim 1, wherein: the closed-loop, metered hydraulic circuit includes at least one metering valve configured to meter fluid from the second pump to the second actuator; and once the combiner valve is closed and the second pump is at zero displacement during the transition from operation of only the first actuator to operation of both the first and second actuators, the controller is further configured to cause the at least one metering valve to meter fluid and to increase displacement of the second pump. ### Claim 7 (depends on 1) The hydraulic system of claim 1, wherein: the closed-loop, metered hydraulic circuit includes at least one metering valve configured to meter fluid from the second pump to the second actuator; wherein the at least one input device is further configured to receive input indicative of a desire to actively operate the first and second actuators; and wherein, during transition from active operation of both the first and second actuators to active operation of only the first actuator, the controller is configured to destroke the second pump and to close the at least one metering valve. ### Claim 8 (depends on 7) The hydraulic system of claim 7, wherein, once the combiner valve is closed and the second pump is at zero displacement during transition from operation of both the first and second actuators to operation of only the first actuator, the controller is further configured to increase the displacement of the second pump, to cause the at least one metering valve to meter fluid, and to increase the displacement of the first actuator. ### Claim 9 (depends on 1) The hydraulic system of claim 1, further including a boost pump configured to provide feed to the second pump. ### Claim 10 (depends on 9) The hydraulic system of claim 9, wherein the boost pump is an auxiliary pump configured to also provide pressurized fluid to an auxiliary circuit. ### Claim 11 (depends on 10) The hydraulic system of claim 10, wherein: the boost pump is a first boost pump; and the hydraulic system further includes a second dedicated boost pump configured to provide feed to the second pump. ### Claim 12 (depends on 1) The hydraulic system of claim 1, further including an accumulator configured to selectively receive pressurized fluid from and discharge accumulated fluid to the second pump. ### Claim 13 A machine, comprising: a frame; an engine mounted to the frame; a traction device configured to support the frame and propel the machine; an implement pivotally connected to the frame; a closed-loop, meterless hydraulic circuit having a first pump driven by the engine to pressurize fluid, and a first actuator fluidly connected to the first pump; a closed-loop, metered hydraulic circuit having a second pump driven by the engine to pressurize fluid, a second actuator configured to move the implement, and at least one metering valve fluidly disposed between the second pump and the second actuator; a combiner valve configured to selectively direct fluid from the closed-loop, metered hydraulic circuit to the closed-loop, meterless hydraulic circuit; at least one boost pump configured to provide feed to the second pump; at least one input device configured to receive input indicative of a desire to actively operate the closed-loop, meterless hydraulic circuit and the closed-loop, metered hydraulic circuit; and a controller in communication with the at least one input device and the combiner valve, wherein, when input is received indicative of a desire to transition between active operation of only the first actuator to simultaneous operation of both the first and second actuators, the controller is configured to simultaneously destroke the second pump, close the combiner valve, and decrease a displacement of the first actuator. ### Claim 14 (depends on 13) The machine of claim 13, further including an accumulator configured to selectively receive pressurized fluid from and discharge accumulated fluid to the second pump during startup of the engine. ### Claim 15 A method of operating a hydraulic system, comprising: circulating fluid from a first pump to a first actuator in a closed-loop, meterless manner; circulating fluid from a second pump to a second actuator in a closed loop, metered manner; selectively directing fluid from the second pump to the first actuator; wherein, during active operation of only the second actuator, the method further includes: inhibiting fluid from the second pump from flowing to the first actuator; and destroking the first pump; wherein, upon receiving input indicative of a desire to transition from active operation of only the first actuator to active operation of both the first and second actuators, the method further includes; responsively and simultaneously destroking the second pump, inhibiting fluid from the second pump from flowing to the first actuator, and decreasing a displacement of the first actuator; and once the second pump is at zero displacement during transition from operation of only the first actuator to operation of both the first and second actuators, the method further includes: metering fluid to the second actuator; and increasing a displacement of the second pump. ### Claim 16 (depends on 15) The method of claim 15, wherein: during active operation of only the first actuator, the method further includes simultaneously directing fluid from both the first and second pumps to the first actuator; and during simultaneous operation of both the first and second actuators, the method further includes inhibiting fluid from the second pump from flowing to the first actuator. ### Claim 17 (depends on 13) The machine of claim 13, wherein the closed-loop, meterless hydraulic circuit is a hydrostatic transmission circuit. ### Claim 18 (depends on 17) The machine claim 17, wherein the closed-loop, metered hydraulic circuit is an implement circuit. ### Claim 19 (depends on 13) The machine of claim 13, wherein the at least one boost pump includes a first boost pump and second boost pump configured to provide feed to the second pump. ### Claim 20 (depends on 15) The method of claim 15, further including operating a boost pump to provide fluid to the second pump.