ELECTRICALLY DRIVEN HYDROGEN PRESSURE BOOSTER FOR A HYDROGEN DRIVEN VEHICLE

Abstract

An electrically driven hydrogen pressure booster for a hydrogen driven vehicle includes an inlet for receiving a gas. Also included is a plurality of chambers for compressing the gas, wherein each of the plurality of chambers includes a piston operably coupled to, and driven by, a crankshaft, wherein the crankshaft is driven by an electric motor. Further included is a pipe for transferring the gas between at least two of the plurality of chambers. Yet further included is an outlet for expelling the gas.

Description

BACKGROUND OF THE INVENTION

The present invention relates to electric motors, and more particularly to gas boosters for electric motors.

Electrically driven automotive vehicles can rely on batteries as well as fuel cells to provide electrical power. A typical fuel cell utilizes compressed hydrogen gas to generate, from the reactions of hydrogen and oxygen, to electricity used to power the electric motor of the vehicle. Previous attempts to provide fuel cells capable of generating sufficient power for such vehicles have been unsuccessful for a number of reasons, including the properties of the hydrogen utilized by the fuel cell.

Hydrogen is a “small” gas and is challenging to capture and seal. Hydrogen is also prone to excessive heat buildup, thereby rendering components and systems intended to harness and manipulate the hydrogen inefficient or inoperable. In order to effectively generate power for an electric vehicle, the hydrogen needs to have a high gas compression ratio. The compression leads to elevated hydrogen temperatures that, combined with a high gas flow rate, pose sufficient sealing challenges.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment, an electrically driven hydrogen pressure booster for a hydrogen driven vehicle includes an inlet for receiving a gas. Also included is a plurality of chambers for compressing the gas, wherein each of the plurality of chambers includes a piston operably coupled to, and driven by, a crankshaft, wherein the crankshaft is driven by an electric motor. Further included is a pipe for transferring the gas between at least two of the plurality of chambers. Yet further included is an outlet for expelling the gas.

According to another embodiment, provided is a method of compressing a gas used in a hydrogen driven vehicle having a crankshaft of a booster device coupled to an electric motor. The method includes receiving the gas at an inlet of the booster device at a first pressure. Further included is compressing the gas to a second pressure that is higher than the first pressure in a first piston assembly having a piston driven by the crankshaft. Yet further included is expelling the gas at an outlet of the booster device at an outlet pressure higher than the first pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a top perspective view of a hydrogen booster used with a fuel cell in a hydrogen driven vehicle;

FIG. 2 is a top perspective, phantom view of the booster;

FIG. 3 is a top plan view of a plurality of chambers of the booster operably coupled to a crankshaft;

FIG. 4 is a top cross-sectional view of the booster;

FIG. 5 is an elevational view of a low pressure side of the booster; and

FIG. 6 is an elevational view of a high pressure side of the booster.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, a booster is illustrated generally as 10 and may be used to compress hydrogen used by a fuel cell in a hydrogen driven vehicle (not illustrated) to provide power to an assembly requiring power. The booster 10 functions to compress a gas, such as hydrogen, to a desired pressure suitable for powering and increasing the efficiency of the automotive vehicle.

The booster 10 includes an outer casing 12 that houses components of the booster 10 and may be in the form of a “clamshell” type housing having a top portion 14 and a bottom portion 16 that may be operably coupled to one another via a plurality of mechanical fasteners 18, such as screws, bolts or the like, or alternatively by welding or brazing the top portion 14 and bottom portion 16 together.

Referring now to FIG. 3, the interior of the booster 10 includes a plurality of chambers for sequentially compressing the gas taken in through an inlet 20 (FIG. 4). In the illustrated embodiment, the booster 10 is shown as having four chambers 22, 24, 26, and 28, but it is contemplated that more or fewer chambers may be employed to sequentially compress the gas. Irrespective of the number of chambers, and for the purposes of the description, the booster 10 includes a first chamber 22, a second chamber 24, a third chamber 26 and a fourth chamber 28. Each chamber 22, 24, 26, and 28, is defined by a piston 30 disposed within a piston sleeve 32. Each piston 30 is operably connected to a crankshaft 34 which is driven by the aforementioned electric motor. Each chamber 22, 24, 26 and 28 is of a distinct diameter and functions to compress the gas to distinct pressures as the gas exits each respective chamber. In one embodiment, the diameters of the respective chambers typically will decrease from the first chamber 22 to the fourth chamber 28. The distinct pressures achieved by the chambers typically increase as the gas is transferred from the first chamber 22 to the fourth chamber 28. For example, experimental results have shown that a volume of gas may enter the inlet 20 (FIG. 4) of the first chamber 22 at a pressure of approximately 100-125 psi, exit the first chamber 22 at approximately 400-500 psi, exit the second chamber 24 at approximately 1,400-1,600 psi, exit the third chamber 26 at approximately 3,000-4,500 psi, and exit the fourth chamber 28 at approximately 8,000-12,000 psi. The pressure ranges cited above are merely illustrative and it is envisioned that the booster 10 may be modified to provide several other pressure ranges that may be achieved in one or more of the chambers, based on the desired application of use.

Each chamber 22, 24, 26 and 28, includes at least one seal 36 and bearing 38 between the piston 30 and the respective piston sleeve 32 in order to facilitate efficient cycling of the piston 30 within the piston sleeve 32 during operation. As previously described, each piston 30 is operably coupled to, and driven by, the crankshaft 34 which extends through the booster 10 and is substantially enclosed within the outer casing 12 (FIG. 2). The crankshaft 34 typically extends to an exterior portion of the outer casing 12 as well, and associated components are attached thereto.

Referring now to FIG. 4, extending to an exterior portion of the outer casing 12 allows an operable connection to the electric motor. Proximate at least one, but typically two, of the surfaces of the outer casing 12, and coupled to the crankshaft 34, is a metal matrix composite (MMC) bearing 40 and adapter 42. The electric motor is capable of driving the crankshaft 34 at various controllable rotational speeds. One illustrative example uses a 110v electric motor to rotate the crankshaft 34 at approximately 120-150 RPM, and more specifically 135 RPM. It is contemplated that the electric motor used to drive the crankshaft 34, and hence the booster 10, is also employed to drive the wheels of the automotive vehicle. In the contemplated embodiment, such an arrangement further enhances the overall efficiency of the system, based on the ability to harness power during regenerative braking of the automotive vehicle. Harnessing power during regenerative braking provides the ability to facilitate driving of the booster 10, while drawing less on the electric motor for this function. Additionally, a flywheel 44 may be configured to operably couple to the crankshaft 34, such that stored energy may be delivered to the crankshaft 34 for periods of time that the driving electric motor is off or running at a lower energy delivering condition. Although some of the elements of the booster 10 are illustrated and described as being disposed at exterior portions of the outer casing 12, it is conceivable that some or all of these components may reside, wholly or partially, within the outer casing 12.

Referring to FIGS. 5 and 6, the booster 10, in the four chamber embodiment illustrated and described, may be characterized as having a low pressure side 60 (FIG. 5) and a high pressure side 70 (FIG. 6). The low pressure side 60 includes the first chamber 22 and the second chamber 24, and as can be seen from the illustration, includes pistons 30 of distinct diameters that function to compress the gas to distinct pressures. Although numerous diameters may be employed to achieve the intended performance of the booster 10, one such embodiment includes a diameter of approximately 1.4 inches (in.) to 1.6 in. (3.5 cm. to 4.1 cm.) for the piston 30 of the first chamber 22, with a diameter of approximately 0.75 inches (in.) to 0.85 in. (1.9 cm. to 2.2 cm.) for the piston 30 of the second chamber 24. Turning to the high pressure side 70 that includes the third chamber 26 and the fourth chamber 28, which produce compressed gas having a higher pressure than that of the low pressure side chambers, one embodiment includes a diameter of approximately 0.5 inches (in.) to 0.6 in. (1.3 cm. to 1.5 cm.) for the piston 30 of the third chamber 26 and a diameter of approximately 0.25 inches (in.) to 0.35 in. (0.6 cm. to 0.9 cm.) for the fourth chamber 28. Each chamber is properly sealed, as are all pathways in which the gas travels.

In operation, a hydrogen electrolizer cycles filtered water stored in the vehicle (estimated at about 1 liter per “full tank”) and the gas, such as hydrogen, from the atmosphere. The gas, such as hydrogen, enters the inlet 20 that is typically located in close proximity to the first chamber 22 at a relatively low pressure, such as 100-125 psi. The gas is then transferred to the first chamber 22 and compressed to a higher pressure by the piston 30 as crankshaft 34 is rotated by the electric motor, such as the aforementioned 110v electric motor. The gas then exits the first chamber 22 at a pressure greater than that of which it had at entry to the first chamber 22 and enters the second chamber 24. Similarly, the second chamber 24 further compresses the gas to a pressure greater than that of which it had at entry to the second chamber 24. As illustrated, transfer of the gas between the second chamber 24 and the third chamber 26 may be facilitated by the use of a tube or pipe 50. Furthermore, such a tube or pipe 50 may be employed throughout the booster 10 to facilitate effective transfer of the gas from inlet 20 to the first chamber 22, second chamber 24, third chamber 26 and fourth chamber 28, or may be formed of a plurality of pipes to effectuate the gas transfer. The pipe 50 may be formed of various materials, with copper being a suitable example of such a material.

Continuing on through the operation, the gas then is transferred to the third chamber 26, whereupon it is compressed to yet a greater pressure. The operation is carried on by transfer of the gas to the fourth chamber 28, where the gas is then compressed to a final pressure. After the final compression, the gas is then expelled out an outlet 46 that is typically located proximate the fourth chamber 28. Upon expulsion through the outlet 46, the highly compressed gas is pressurized to approximately 8,000-12,000 psi, and more typically approximately 10,000 psi. Compression to a pressure this great of a gas such as hydrogen, for example, is extremely useful for successfully and efficiently powering an automotive vehicle.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

1. An electrically driven hydrogen pressure booster for a hydrogen driven vehicle comprising:

an inlet for receiving a gas;

a plurality of chambers for compressing the gas, wherein each of the plurality of chambers includes a piston operably coupled to, and driven by, a crankshaft, wherein the crankshaft is driven by an electric motor;

a pipe for transferring the gas between at least two of the plurality of chambers; and

an outlet for expelling the gas.

2. The booster of claim 1, wherein the gas is hydrogen.

3. The booster of claim 1, wherein the inlet receives the gas at a first pressure and the outlet expels the gas at a second pressure.

4. The booster of claim 3, wherein the second pressure is greater than the first pressure.

5. The booster of claim 3, wherein the first pressure is approximately 100 psi.

6. The booster of claim 3, wherein the second pressure is greater than approximately 8,000 psi.

7. The booster of claim 3, wherein the second pressure is approximately 10,000 psi.

8. The booster of claim 1, wherein the pipe is formed of a copper material.

9. The booster of claim 1, further comprising a casing for at least partially enclosing the booster.

10. The booster of claim 1, further comprising a flywheel operably coupled to the crankshaft.

11. The booster of claim 1, wherein the electric motor drives at least one wheel of the electrically driven vehicle.

12. A method of compressing a gas used in a hydrogen driven vehicle having a crankshaft of a booster device coupled to an electric motor, the method comprising:

receiving the gas at an inlet of the booster device at a first pressure;

compressing the gas to a second pressure that is higher than the first pressure in a first piston assembly having a piston driven by the crankshaft; and

expelling the gas at an outlet of the booster device at an outlet pressure higher than the first pressure.

13. The method of claim 12, further comprising compressing the gas through a plurality of piston assemblies.

14. The method of claim 13, wherein the plurality of piston assemblies comprise the first piston assembly, a second piston assembly, a third piston assembly and a fourth piston assembly.

15. The method of claim 14, wherein the gas is hydrogen.

16. The method of claim 13, further comprising transferring the gas throughout the booster device through a pipe.

17. The method of claim 16, wherein the pipe comprises copper.

18. The method of claim 12, wherein the outlet pressure is greater than approximately 8,000 psi.

19. The method of claim 12, further comprising driving an electric motor with the gas at the outlet pressure.

20. The method of claim 13, wherein the electric motor drives at least one wheel of the electrically driven vehicle.