Accumulator racks

• US 10,247,205 B2
• Filed: 02/03/2015
• Issued: 04/02/2019
• Est. Priority Date: 02/04/2014
• Status: Active Grant

• Current Assignee: DANA Italia SPA (Dana, Inc.)
• Original Assignee: DANA Italia SPA (Dana, Inc.)
• Inventors: Serrao, Lorenzo, Ornella, Giulio, Cosoli, Ettore
• Primary Examiner(s): Kraft, Logan
• Application Number:
  US15/330,060
• Publication Number:
  US 20170037875A1
• Time in Patent Office: 1,519 Days
• CPC Class Codes: B60K 6/12 by means of a chargeable fluidic accumulator
• CPC Class Codes: B60Y 2400/10 Energy storage devices
• CPC Class Codes: F15B 1/024 used as a supplementary power source, e.g. to store energy in idle periods to balance pump load
• CPC Class Codes: F15B 1/027 having accumulator charging devices
• CPC Class Codes: F15B 1/033 with electrical control means
• CPC Class Codes: F15B 1/04 Accumulators
• CPC Class Codes: F15B 1/08 using a gas cushion; Gas charging devices; Indicators or floats therefor
• CPC Class Codes: F15B 2201/205 using gas
• CPC Class Codes: F15B 2201/405 Housings
• CPC Class Codes: F15B 2201/4155 having valve means
• CPC Class Codes: F15B 2201/51 Pressure detection
• CPC Class Codes: F16H 61/4096 with pressure accumulators
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method of charging a hydro-pneumatic energy storage system is described. The system has a first hydro-pneumatic accumulator with a first hollow vessel. Disposed within the first hollow vessel is a first compressible volume containing a first amount of gas. The system has a second hydro-pneumatic accumulator with a second hollow vessel. Disposed within the second hollow vessel is a second compressible volume containing a second amount of gas. The gas contained in the first volume is pre-pressurized to a first hydrostatic pre-charge pressure and the gas contained in the second volume is pre-pressurized to a second hydrostatic pre-charge pressure. The second pre-charge pressure is higher than the first pre-charge pressure. In addition, the gas in the first volume is pressurized by discharging a non-compressible hydraulic fluid into the first vessel while keeping a quantity of non-compressible hydraulic fluid contained in the second vessel constant to keep the pressure of the gas contained in the second volume at the second pre-charge pressure.

Claims

1. A method of charging a hydro-pneumatic energy storage system, the energy storage system comprising a first hydro-pneumatic accumulator comprising a first hollow vessel and, disposed within the first hollow vessel, a first compressible volume containing a first amount of gas, and the system comprising a second hydro-pneumatic accumulator comprising a second hollow vessel and, disposed within the second hollow vessel, a second compressible volume containing a second amount of gas, the method comprising the steps of:

pre-pressurizing the gas contained in the first volume to a first hydrostatic pre-charge pressure and pre-pressurizing the gas contained in the second volume to a second hydrostatic pre-charge pressure, the second pre-charge pressure being higher than the first pre-charge pressure;

pressurizing the gas in the first volume by discharging a non-compressible hydraulic fluid into the first vessel while keeping a quantity of non-compressible hydraulic fluid contained in the second vessel constant to keep the pressure of the gas contained in the second volume at the second pre-charge pressure; and

,

when the pressure of the gas in the first volume reaches the second pre-charge pressure, pressurizing the gas in the second volume by discharging a non-compressible hydraulic fluid into the second vessel.

2. The method of claim 1, further including the step of keeping the quantity of non-compressible hydraulic fluid contained in the first vessel constant to keep the pressure of the gas in the first volume at the first maximum pressure when the pressure of the gas in the first volume reaches a first maximum pressure which is equal to or higher than the second pre-charge pressure.

3. The method of claim 1, wherein pre-pressurizing the gas contained in the first volume to the first pre-charge pressure includes adjusting the first amount of gas, and wherein pre-pressurizing the gas contained in the second volume to the second hydrostatic pre-charge pressure includes adjusting the second amount of gas.

4. The method of claim 1, wherein the non-compressible hydraulic fluid is discharged into the first vessel and into the second vessel through a hydraulic displacement unit driven by an engine or by a vehicle output of an automotive vehicle.

5. A method of discharging a hydro-pneumatic energy storage system, the system comprising a first hydro-pneumatic accumulator comprising a first hollow vessel and, disposed within the first vessel, a quantity of a non-compressible hydraulic fluid and a first volume containing a first amount of gas at a first maximum hydrostatic pressure, and the system comprising a second hydro-pneumatic accumulator comprising a second hollow vessel and, disposed within the second vessel, a quantity of a non-compressible hydraulic fluid and a second volume containing a second amount of gas at a second maximum hydrostatic pressure, the second maximum pressure being higher than or equal to the first maximum pressure, the method comprising the steps of:

letting the gas contained in the second volume expand to at least partially displace the non-compressible hydraulic fluid contained in the second vessel out of the second vessel while keeping the quantity of non-compressible hydraulic fluid contained in the first vessel constant;

when the pressure of the gas contained in the second volume has fallen to the first maximum pressure, letting the gas contained in the first volume expand to at least partially displace the non-compressible hydraulic fluid contained in the first vessel out of the first vessel;

when the pressure of the gas contained in the second volume has fallen to a second pre-charge pressure which is equal to or smaller than the first maximum pressure, halting the expansion of the gas contained in the second volume to keep the pressure of the gas contained in the second volume at the second pre-charge pressure; and

when the pressure of the gas contained in the first volume has fallen to a first pre-charge pressure which is smaller than the second pre-charge pressure, halting the expansion of the gas contained in the first volume to keep the pressure of the gas contained in the first volume at the first pre-charge pressure.

6. The method of claim 5, wherein the non-compressible hydraulic fluid displaced out of the first vessel and out of the second vessel drives a hydraulic displacement unit drivingly engaged with an engine or with a vehicle output of an automotive vehicle.

7. The method of claim 5, wherein a ratio of the first maximum pressure less the second pre-charge pressure to the second pre-charge pressure less the first pre-charge pressure is less than or equal to 0.2.

8. The method of claim 7, wherein the ratio of the first maximum pressure less the second pre-charge pressure to the second pre-charge pressure less the first pre-charge pressure is less than or equal to 0.1.

9. The method of claim 5, wherein the first pre-charge pressure is at least 10 bar.

10. The method of claim 9, wherein the first pre-charge pressure is at least 30 bar.

11. The method of claim 10, wherein the first pre-charge pressure is at least 50 bar.

12. The method of claim 5, wherein the second pre-charge pressure is at least twice the first pre-charge pressure.

13. The method of claim 12, wherein the second pre-charge pressure is at least three times the first pre-charge pressure.

14. The method of claim 13, wherein the second pre-charge pressure is at least 3.5 times the first pre-charge pressure.

15. A hydro-pneumatic energy storage system, comprising:

a first hydro-pneumatic accumulator comprising a first hollow vessel and, disposed within the first vessel, a first compressible volume containing a first amount of gas;

a second hydro-pneumatic accumulator comprising a second hollow vessel and, disposed within the second vessel, a second compressible volume containing a second amount of gas;

a feed pipe;

at least one control valve selectively fluidly connecting the accumulators to the feed pipe;

at least one pressure sensor for measuring a hydrostatic pressure in the feed pipe and/or in the accumulators; and

a control unit for controlling the at least one control valve, the control unit having a charge mode and a discharge mode;

wherein, when the control unit is in the charge mode, the control unit is configured to selectively fluidly connect the accumulators to the feed pipe and to selectively fluidly disconnect the accumulators from the feed pipe by pre-pressurizing the gas contained in the first volume to a first hydrostatic pre-charge pressure and pre-pressurizing the gas contained in the second volume to a second hydrostatic pre-charge pressure, the second pre-charge pressure being higher than the first pre-charge pressure;

pressurizing the gas in the first volume by discharging a non-compressible hydraulic fluid into the first vessel while keeping a quantity of non-compressible hydraulic fluid contained in the second vessel constant to keep the pressure of the gas contained in the second volume at the second pre-charge pressure; and

, when the pressure of the gas in the first volume reaches the second pre-charge pressure, pressurizing the gas in the second volume by discharging a non-compressible hydraulic fluid into the second vessel; and

wherein, when the control unit is in the discharge mode, the control unit is configured to selectively fluidly connect the accumulators to the feed pipe and to selectively fluidly disconnect the accumulators from the feed pipe by letting the gas contained in the second volume expand to at least partially displace the non-compressible hydraulic fluid contained in the second vessel out of the second vessel while keeping the quantity of non-compressible hydraulic fluid contained in the first vessel constant;

when the pressure of the gas contained in the second volume has fallen to the first maximum pressure, letting the gas contained in the first volume expand to at least partially displace the non-compressible hydraulic fluid contained in the first vessel out of the first vessel;

when the pressure of the gas contained in the second volume has fallen to a second pre-charge pressure which is equal to or smaller than the first maximum pressure, halting the expansion of the gas contained in the second volume to keep the pressure of the gas contained in the second volume at the second pre-charge pressure; and

when the pressure of the gas contained in the first volume has fallen to a first pre-charge pressure which is smaller than the second pre-charge pressure, halting the expansion of the gas contained in the first volume to keep the pressure of the gas contained in the first volume at the first pre-charge pressure.

16. The hydro-pneumatic energy storage system of claim 15, further comprising a hydraulic displacement unit in fluid communication with the accumulators through the feed pipe, the hydraulic displacement unit being drivingly engaged or selectively drivingly engaged with at least one of an engine of an automotive vehicle, a vehicle output of an automotive vehicle and a hydraulic implement.

17. The hydro-pneumatic energy storage system of claim 15, further comprising a compressor in fluid communication with the first volume and with the second volume, the compressor being configured to pre-pressurize the gas contained in the first volume to the first pre-charge pressure by adjusting the first amount of gas, and the compressor being configured to pre-pressurize the gas contained in the second volume to the second pre-charge pressure by adjusting the second amount of gas.

18. The hydro-pneumatic energy storage system of claim 15, wherein the first volume and/or the second volume are formed by one of a closed bladder, an elastic diaphragm and a floating piston.