# US 11,441,585 B2 · Hydraulic system with energy recovery

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- Number: US 11,441,585 B2
- Document ID: US11441585B2
- Status: Granted
- Kind: B2
- Application number: 17/122,987
- Filed: 2020-12-15
- Published: 2021-06-24
- Granted: 2022-09-13
- Earliest claimed: 2019-12-20
- Assignees: Dana Motion Systems Italia S.R.L.
- Applicants: Dana Motion Systems Italia S.R.L.
- Inventors: Luca Buscicchio; Piergiorgio Trinchieri
- Web page: https://patentgrep.com/patent/US11441585B2

## CPC

- F15B 21/14: Energy-recuperation means
- E02F 9/2296: {Systems with a variable displacement pump}
- E02F 9/2217: {with energy recovery arrangements, e.g. using accumulators, flywheels}
- F15B 2211/20515: Electric motor
- F15B 2211/20569: capable of working as pump and motor
- F15B 2211/40576: Assemblies of multiple valves
- F15B 2211/41581: being connected to an output member and a return line
- F15B 2211/428: actuated by fluid pressure
- F15B 2211/46: Control of flow in the return line, i.e. meter-out control
- F15B 2211/6313: the pressure being a load pressure
- F15B 2211/7052: Single-acting output members
- F15B 2211/761: Control of a negative load, i.e. of a load generating hydraulic energy
- 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)

## Abstract

A hydraulic system, comprising: a hydraulic pump, a hydraulic load, and an electric machine. The electric machine working as an electric generator and mechanically coupled with said hydraulic pump. A low-pressure fluid tank and a valve assembly comprising one or more valves selectively fluidly connecting the hydraulic load with the low-pressure fluid tank.

## Claims

### Claim 1

A hydraulic system, comprising:
a hydraulic pump/motor;
a hydraulic load;
an electric machine configured to work as an electric generator and mechanically coupled with the hydraulic pump/motor;
a low-pressure fluid tank;
a delivery passage connecting the hydraulic pump/motor to the hydraulic load;
a first valve positioned along a branch bypassing part of the delivery passage, the first valve connecting the hydraulic load with the hydraulic pump/motor when pressure at the hydraulic load is above a threshold pressure;
an exit passage connecting the hydraulic load to the low-pressure fluid tank and bypassing the hydraulic pump/motor; and
a second valve positioned along the exit passage, the second valve connecting the hydraulic load with the low-pressure fluid tank when the pressure at the hydraulic load is below the threshold pressure, wherein the second valve is a pilot valve.

### Claim 2 (depends on 1)

The hydraulic system according to claim 1, further comprising a solenoid drivable 2-way valve which, in a first position, connects the delivery passage and the hydraulic load and, in a second position, connects the exit passage and the branch bypassing part of the delivery passage to the hydraulic load.

### Claim 3 (depends on 1)

The hydraulic system according to claim 1, wherein the first valve is a sequence valve.

### Claim 4 (depends on 1)

The hydraulic system according to claim 1, further comprising a safety relief valve and a safety relief passage connected to the delivery passage.

### Claim 5 (depends on 1)

The hydraulic system of claim 1, wherein the bypass branch, the delivery passage, and the exit passage meet at a node and the node is connected to the hydraulic load, and
further comprising a two-position valve connecting the node and the hydraulic load, a first position of the two-position valve flowing fluid in a supply direction, and a second position of the two-position valve flowing fluid in a regeneration direction, and
a check valve positioned along the delivery passage.

### Claim 6

A hydraulic system, comprising:
a hydraulic pump/motor delivering fluid in a supply direction and receiving fluid in a regeneration direction;
a hydraulic load;
an electric machine mechanically coupled with the hydraulic pump/motor;
a low-pressure fluid tank;
a delivery passage connecting the hydraulic pump/motor to the hydraulic load;
a bypass branch bypassing part of the delivery passage;
a first valve positioned along the bypass branch, the first valve comprising an open position which flows fluid in the regeneration direction and a closed position which prevents flow, and the first valve moving to the open position when a pressure from the hydraulic load is above a pressure threshold, wherein the first valve is a sequence valve;
an exit passage connecting the hydraulic load to the low-pressure fluid tank and bypassing the hydraulic pump/motor;
a second valve positioned along the exit passage, the second valve opening to flow fluid to the low-pressure fluid tank when the pressure from the hydraulic load is below the pressure threshold; and
a third valve preventing flow in the regeneration direction within a portion of the delivery passage.

### Claim 7 (depends on 6)

The hydraulic system of claim 6, wherein the third valve is a solenoid drivable 2-way valve which, in a first position, connects the delivery passage and the hydraulic load and, in a second position, connects the exit passage and the bypass branch to the hydraulic load.

### Claim 8 (depends on 6)

The hydraulic system of claim 6, wherein the second valve is a pilot valve.

### Claim 9 (depends on 6)

The hydraulic system of claim 6, wherein the third valve is a check valve positioned along the delivery passage.

### Claim 10 (depends on 9)

The hydraulic system of claim 9, wherein the bypass branch, the delivery passage, and the exit passage meet at a node and the node is connected to the hydraulic load.

### Claim 11 (depends on 10)

The hydraulic system of claim 10, wherein a fourth valve connects the node and the hydraulic load, and wherein the fourth valve is a two-position valve which, in a first position, flows fluid in the supply direction and, in a second position, flows fluid in the regeneration direction.

### Claim 12

A hydraulic system, comprising:
a hydraulic pump/motor delivering fluid in a supply direction and receiving fluid in a regeneration direction;
a hydraulic load;
an electric machine mechanically coupled with the hydraulic pump/motor;
a low-pressure fluid tank;
a delivery passage connecting the hydraulic pump/motor to the hydraulic load;
a bypass branch bypassing part of the delivery passage;
a first valve positioned along the bypass branch, the first valve comprising an open position which flows fluid in the regeneration direction and a closed position which prevents flow, and the first valve moving to the open position when a pressure from the hydraulic load is above a pressure threshold;
an exit passage connecting the hydraulic load to the low-pressure fluid tank and bypassing the hydraulic pump/motor;
a second valve positioned along the exit passage, the second valve opening to flow fluid to the low-pressure fluid tank when the pressure from the hydraulic load is below the pressure threshold; and
a 2-way valve which, in a first position, connects the delivery passage and the hydraulic load and, in a second position, connects the exit passage and the bypass branch to the hydraulic load.