Patent Application
20120031911
1. Field of the Invention
The present invention relates to integrated pressurized fluid systems in general, sudh as for hydraulic regenerative drive systems, and, more particularly, to an integrated pressurized fluid system including a pressure vessel assembly containing at least one hydraulic fluid accumulator.
2. Description of the Prior Art
In conventional integrated pressurized fluid systems the recovered energy is normally accumulated in flywheel accumulators, in electrochemical batteries or in hydraulic fluid accumulators. The latter are of known technology and, in comparison with the other recovery and accumulation arrangements, they are more flexible in use, notably in connection with a vehicular transmission to which they are connected. On the other hand they remain less efficient in terms of mass and volume and consequently raise serious problems for fitting onto motor vehicles. In addition to penalizing the energy savings obtained, these problems of dead weight and bulk lead to high costs linked either with the hydraulic fluid accumulator itself or, mainly, with the modifications that have to be made to the vehicle to fit the accumulator. The result is that the motor vehicles equipped with the hydraulic fluid accumulator are no longer standard in any way and are therefore much more expensive to produce and maintain and that, furthermore, the equipment used for this installation cannot be transposed to another vehicle or modulated in size, which increases the overall cost of such an installation.
Accordingly, it is the intent of this invention to overcome these shortcomings of the prior art by providing a compact pressure vessel assembly combining all the accumulation functions and capable of being fitted without any substantial modification to various types of pressurized fluid systems, including standard motor vehicles equipped with hydraulic regenerative drive system designed for charging and discharging the hydraulic fluid accumulators.
The present invention provides a pressure vessel assembly for use in an integrated pressurized fluid system, such as for a hydraulic regenerative drive system.
The pressure vessel assembly of the present invention comprises an enclosed outer casing, at least one internal tube extending within the casing, at least one fluid accumulator disposed within the at least one internal tube, and at least one cooling passage provided within the at least one internal tube and defined by a clearance between the at least one hydraulic fluid accumulator and the at least one internal tube. The pressure vessel assembly further includes a fluid storage compartment formed within the outer casing outside the at least one internal tube. The fluid storage compartment is at least partially filled with a working fluid, such as oil.
The pressurized fluid system Of the present invention includes a cooling fan allowing forced airflow through the cooling passage for forced cooling of the at least one hydraulic fluid accumulator and the working fluid in the storage compartment of the pressure vessel assembly.
The pressurized fluid system of the present invention further includes a pressurized gas reservoir external to the outer casing so that the pressurized gas reservoir is in fluid communication with the compartment within the outer casing for pressurizing the working fluid within the compartment in the outer casing.
Moreover, according to the preferred embodiment of the present invention, the hydraulic fluid accumulator is placed inside the internal tube, centered and spaced inside the internal tube with at least one spiral wrapping around the hydraulic fluid accumulator.
Furthermore according to the preferred embodiment of the present invention, the outer casing of the pressure vessel includes a substantially tubular housing and end members secured at opposite distal ends of the housing.
Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in light of the accompanying drawings, wherein:
The preferred embodiment of the present invention will now be described with the reference to accompanying drawings.
As illustrated in
Preferably, the motor/pump 2 is a positive displacement, reversible hydraulic unit, such as a high-pressure hydraulic piston machine that functions both as hydraulic pump and hydraulic motor when reversed. Alternatively, the motor/pump 2 is a variable-displacement hydraulic unit. It will be appreciated that any appropriate hydraulic motor/pump unit is within the scope of the present invention. In the application for the hydraulic regenerative drive system of a motor vehicle (not shown), the motor/pump 2 is connected to a driveline of the motor vehicle through the drive shaft 3.
As further illustrated in
Further preferably, the hydraulic fluid 17 in the storage compartment 11 of the pressure vessel assembly 10 is at low-pressure created by an external pressurized gas reservoir 6 fluidly communicating with the storage compartment 11, as illustrated in
The pressure vessel assembly 10, shown in detail in
The outer casing 12 of the pressure vessel assembly 10 is further provided with a plurality of smaller diameter, cylindrical internal tubes 18 secured therewithin. Each of the plurality of the cylindrical internal tubes 18 has a longitudinal axis 19 substantially parallel to the central axis 13 of the cylindrical housing 14 and is sized to receive one of the hydraulic fluid accumulators 20 that fit inside the internal tube 18 with a nominal clearance. The clearance between the hydraulic fluid accumulator 20 and the internal tube 18 defines a cooling passage for receiving a flow of an appropriate cooling fluid, such as air, therethrough for cooling the hydraulic fluid accumulator 20 and the working hydraulic fluid within the storage compartment 11 of the pressure vessel assembly 10. Preferably, the nominal clearance is on the order of one-quarter of an inch.
Further preferably, the internal tubes 18 have substantially the same length as the housing 12 and extend through the flat end members 15 and 16. All the internal tubes 18 are assembled such that their ends are flush. In order to achieve this, corresponding circular holes 22 are punched in each of the end members 15 and 16 of the pressure vessel assembly 10 to accommodate the internal tubes 18. Thus, the working fluid storage compartment 11 is defined by a space between an inner peripheral surface 14a of the cylindrical housing 14, an outer peripheral surface 18a of the internal tubes 18, and the end members 15 and 16.
The hydraulic fluid accumulators 20 are secured within the internal tubes 18 of the pressure vessel assembly 10 by any appropriate means known to those skilled in the art. By way of example, distal ends of the internal tubes 18 may be closed with perforated circular cover members 25 (shown in
In an assembled condition, the end members 15 and 16 are inserted into the cylindrical housing 14 and aligned such as to be parallel to each other and perpendicular to the central axis 13 of the housing 14. The end members 15 and 16 are recessed sufficiently such that sufficient weld material can be applied between the raised flange 15a and 16a of the end plates 15 and 16, respectively, and an inner peripheral surface 14a of the cylindrical housing 14. At the time of alignment of the end plates 15 and 16, the punched circular holes 22 in both end members 15 and 16 must be aligned such that the internal tubes 18 may be passed through the completed cylindrical housing 14 and the end members 15, 16 and aligned flush with the cylindrical housing 14. Once the internal tubes 18 are positioned, sufficient weld is applied to the raised flange 15a and 16a of the end plates 15 and 16 and the distal ends of the cylindrical housing 14 so as to be leak tight to the desired pressure rating of the pressure vessel assembly 10. The pressure vessel assembly 10 shall be designed such that the material thickness and welds are sufficient to contain the working pressure of the system with an appropriate safety factor.
The pressure vessel assembly 10 of the pressurized fluid system 1 according to the preferred embodiment of the present invention further allows for efficient cooling of the housing 12 of the pressure vessel assembly 10 via forced airflow through the pressure vessel assembly 10. For this purpose, as illustrated in
Moreover, according to the preferred embodiment of the present invention, the hydraulic fluid accumulators 20 are placed inside the internal tubes 18, centered and spaced inside the internal tubes 18 with at least one, preferably two, spiral wrappings 26 around the hydraulic fluid accumulators 20, as illustrated in
Furthermore, a number of internal baffles 28 within the outer casing 12 are employed to increase a rate of thermal conduction from the working hydraulic fluid 17 within the storage compartment 11 of the pressure vessel assembly 10 to the internal tubes 18, reduce the amount of the hydraulic fluid movement within the storage compartment 11, and strengthen the pressure vessel assembly 10. It will be appreciated by those of ordinary skill in the art that arrangement of the internal baffles 28 can be varied to accommodate various angles of inclination of the motor vehicle.
The entire pressurized fluid system 1 is scaled such that sufficient working hydraulic fluid 17 may be contained within the storage compartment 11 of the pressure vessel assembly 10 between the inner peripheral surface 14a of the housing 14, the outer peripheral surface 18a of the internal tubes 18, and the end members 15 and 16 to allow the accumulators 20 to be charged with fluid.
Care shall be used in the selection of the materials and thickness of the pressure vessel elements to optimize both the pressure capacity as well as the heat transfer capacity of the pressure vessel assembly 10.
The cylindrical design of the pressure vessel assemb1y 10 also optimizes pressure capacity as a function of system weight. The flat end members 15 and 16 with the raised lips 15a and 16a, respectively, around the circumference strengthen the external connection to the cylindrical housing 12 as well as the connections to the internal tubes 18.
The design also allows for increased protection of the hydraulic fluid accumulators 20. This protection consists of the cylindrical housing 14, the working hydraulic fluid 17, and the internal tubes 18, as well as the separation distances. The design is intended to increase the protection of the charged accumulators 20 from ballistic penetration. In addition to this protection the design also allows for the re-direction of any fluid discharged from the punctured accumulator. The nature of the design directs the flow of any working fluid out the ends of the pressure vessel assembly 10. Prudent placement/orientation of the complete system would direct any expelled fluid flow in a safe direction.
Therefore, the integrated pressurized fluid system in accordance with the present invention includes a novel pressure vessel assembly comprising an enclosed outer casing, at least one internal tube extending within the casing, at least one fluid accumulator disposed within the at least one internal tube, and at least one cooling passage provided within the at least one internal tube adjacent to the at least one fluid accumulator for receiving a flow of a cooling fluid therethrough for cooling the at least one fluid accumulator.
The foregoing description of the preferred embodiment of the present invention has been presented for the purpose of illustration in accordance with the provisions of the Patent Statutes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments disclosed hereinabove were chosen in order to best illustrate the principles of the present invention and its practical application to thereby enable those of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated, as long as the principles described herein are followed. Thus, changes can be made in the above-described invention without departing from the intent and scope thereof. It is also intended that the scope of the present invention be defined by the claims appended thereto.
This Application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/504,188 filed Sep. 22, 2003 by Kenric Rose.
| Number | Date | Country | |
|---|---|---|---|
| 60504188 | Sep 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10572908 | Oct 2006 | US |
| Child | 13272868 | US |
