US20140196600A1

US20140196600A1 - Air engine with rotatable intake-exhaust mechanism

Info

Publication number: US20140196600A1
Application number: US13/831,274
Authority: US
Inventors: Chih-Yung Huang; Jhih-Jie You; Cheng-Kuo Sung; Chao-An Lin
Original assignee: National Tsing Hua University NTHU
Current assignee: National Tsing Hua University NTHU
Priority date: 2013-01-11
Filing date: 2013-03-14
Publication date: 2014-07-17
Also published as: TWI495783B; TW201428175A

Abstract

An air engine includes a cylinder, a piston, a gas supply and an intake-exhaust mechanism. The gas supply supplies a compressed gas to move the piston reciprocating in the cylinder. The intake-exhaust mechanism connected to the cylinder and the gas supply includes a body and an intake-exhaust assembly. The body has a chamber, and an intake channel, an exhaust channel, an inlet port and an outlet port, which communicate with the chamber. The intake-exhaust assembly, rotatable within the chamber, controls the inlet port to be connected to the intake channel, and further controls the outlet port to be connected to the exhaust channel, so that the compressed gas enters the cylinder via the inlet port and the intake channel to drive the piston. After driving the piston, the compressed gas becomes an exhaust gas, which is exhausted from the cylinder via the exhaust channel and the outlet port.

Description

This application claims priority of No. 102101162 filed in Taiwan R.O.C. on Jan. 11, 2013 under 35 USC 119, the entire content of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to an air engine, and more particularly to an air engine with a rotatable intake-exhaust mechanism,
2. Related Art
In a conventional internal combustion engine, rotating cams push an intake valve and an exhaust valve to control intake and exhaust timings, respectively. Because the intake valve and the exhaust valve are trumpet-shaped and the operations are limited by the cam mechanism, the valves need to open and close gradually to complete every cycle. If the internal combustion engine is modified into the air engine, the efficiency of the air engine cannot be effectively enhanced due to the gradually opening and closing operations of the valves.
The air engine (or air motor) converts the pressure energy of the compressed gas into the mechanical energy to generate the rotary motion and has the function equivalent to the electric motor or hydraulic motor. The air engine is driven by the high-pressure gas and thus generates no contamination upon operation.
The air engine can be installed on the bicycle, motorcycle, vehicle as the main power source to replace the currently used electric motor and internal combustion engine.
Alternatively, the air engine may also serve as the auxiliary power source of the motorcycle or vehicle to reduce the contamination generated by the internal combustion engine.
Because the traffic tool with the air engine has the high development potential, it is a great help to the industrial development if the efficiency of the air engine can be further enhanced.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an air engine with a rotatable intake-exhaust mechanism for achieving the effect of instantaneously opening and closing valves and for effectively increasing the working efficiency of the air engine.
To achieve the above-identified object, the invention provides an air engine including a cylinder, a piston, a gas supply and an intake-exhaust mechanism. The piston is capable of reciprocating in the cylinder. The gas supply supplies a compressed gas to move the piston. The intake-exhaust mechanism is connected to the cylinder and the gas supply and includes a body and an intake-exhaust assembly. The body has a chamber, and an intake channel, an exhaust channel, an inlet port and an outlet port, which communicate with the chamber. The intake channel and the exhaust channel communicate with the chamber and the cylinder. The intake-exhaust assembly is rotatable within the chamber, controls the inlet port to be connected to the intake channel or not upon rotation, and controls the outlet port to be connected to the exhaust channel or not upon rotation, so that the compressed gas enters the cylinder via the inlet port and the intake channel to drive the piston. After driving the piston, the compressed gas becomes an exhaust gas, which is exhausted from the cylinder via the exhaust channel and the outlet port,
With the air engine of the invention, controlling the instantaneous open and close operations of the valves can provide more sufficient intake and exhaust for the engine to increase the efficiency. Because no cam is needed, no complicated mechanism has to be disposed, and no hysteresis phenomenon is caused upon the power transmission of the cam (especially at the high rotating speed). Because no fuel is provided and burned, no contaminated exhaust gas is generated, and no spark plug or high-pressure nozzle is needed to perform the ignition operation. Therefore, the air engine of the invention has the relatively high applicability and economy after the intake and exhaust strokes are improved.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention.

FIG. 1 is a schematic decomposed view showing an air engine according to a first embodiment of the invention.

FIG. 2 is a schematic assembled view showing the air engine according to the first embodiment of the invention:

FIG. 3 is a schematic top view showing the air engine according to the first embodiment of the invention.

FIG. 4A shows a positional relationship between the inlet port and the intake channel according to the first embodiment of the invention.

FIG. 4B shows a positional relationship between the outlet port and the exhaust channel according to the first embodiment of the invention.

FIGS. 4C and 4D are schematic illustrations showing an intake state of the air engine at the same time instant according to the first embodiment of the invention.

FIGS. 4E and 4F are schematic illustrations showing an exhaust state of the air engine at the same time instant according to the first embodiment of the invention.

FIG. 5A is a comparison chart showing a cylinder pressure ratio versus a cylinder volume in a conventional air engine and the air engine according to the first embodiment of the invention.

FIG. 5B is a comparison chart showing openings of the valves with respect to an intake timing and an exhaust timing in the conventional air engine and the air engine according to the first embodiment of the invention.

FIG. 6 is a schematic partial view showing an intake-exhaust assembly according to a second embodiment of the invention.

FIG. 7 is a partial cross-sectional view showing an intake-exhaust assembly according to a third embodiment of the invention.

FIGS. 8A to 8C show three examples of intake-exhaust paths according to the invention.

FIGS. 9A to 9C show three examples of intake/exhaust passages of intake/exhaust members according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
The invention achieves the intake control and the exhaust control in the air engine according to the rotary motion of the intake member and the exhaust member, wherein the conventional cam-type intake valve and exhaust valve are replaced with the intake member and the exhaust member. With this design, the valve can be opened and closed instantaneously, so that the engine has the more sufficient intake and exhaust gas or air. Furthermore, adjusting the angular position of the intake member relative to the exhaust member can change the intake and exhaust timings of the air engine so that the optimum power output curve is obtained. Furthermore, the air passages of the intake member and the exhaust member may have many configurations to satisfy many application occasions of the air engine.
FIG. 1 is a schematic decomposed view showing an air engine 1 according to a first embodiment of the invention. FIG. 2 is a schematic assembled view showing the air engine 1 according to the first embodiment of the invention. FIG. 3 is a schematic top view showing the air engine 1 according to the first embodiment of the invention. Referring to FIGS. 1 to 3, the air engine 1 of this embodiment includes a cylinder 10, a piston 20, a gas supply 30 and an intake-exhaust mechanism 40.
The piston 20 can reciprocate in the cylinder 10. This motion is similar to that of the conventional internal combustion engine, so detailed descriptions thereof will be omitted.
The gas supply 30 supplies a compressed gas (or air) CA to move the piston 20. When the engine is installed in a traffic tool, a high-pressure gas cylinder may serve as the gas supply 30. In an exemplified but non-restrictive example, the pressure of the compressed gas CA is higher than 100 atm.
The intake-exhaust mechanism 40 is connected to the cylinder 10 and the gas supply 30, and is mainly for controlling the intake operation and the exhaust operation of the air engine 1. The intake-exhaust mechanism 40 includes a body 41 and an intake-exhaust assembly 42.
The body 41 has a chamber 41S, and an intake channel 41A, an exhaust channel 41B, an inlet port 41C and an outlet port 41D communicating with the chamber 41S. The intake channel 41A and the exhaust channel 41B communicate with the chamber 41S and the cylinder 10. In this embodiment, the chamber 41S is a through hole.
The intake-exhaust assembly 42 is rotatable within the chamber 41S, controls the inlet port 41C to be connected to the intake channel 41A or not upon rotation, and controls the outlet port 41D to be connected to the exhaust channel 41B or not upon rotation, so that the compressed gas CA enters the cylinder 10 via the inlet port 41C and the intake channel 41A to drive the piston 20. After driving the piston 20, the compressed gas CA becomes an exhaust gas EA, which is exhausted from the cylinder 10 via the exhaust channel 41B and the outlet port 410.
In this embodiment, the intake-exhaust assembly 42 includes a rotating shaft 42A, an intake member 42B and an exhaust member 42C. The intake member 42B is mounted on the rotating shaft 42A and has an intake passage 42B1 that may communicate with the inlet port 41C and the intake channel 41A. The rotating shaft 42A is rotatably disposed in the body 41 through two bearings 92. External covers 91 and 93 are disposed on two sides of the body 41, respectively, to cover the chamber 41S and prevent the dust and particles from entering the chamber 41S. The exhaust member 42C is disposed on the rotating shaft 42A and has an exhaust passage 42C1 that can communicate with the outlet port 410 and the exhaust channel 41B. In another example, the intake member 42B and the exhaust member 42C may be integrally formed with each other to form an integrated member. In still another embodiment, the intake member 42B and/or the exhaust member 42C may be integrally formed with the rotating shaft 42A to form another integrated member.
In addition, the air engine 1 of this embodiment may further include a link 50, a crankshaft 60, a crankshaft sprocket 70, an intake-exhaust sprocket 80 and a chain 90. The link 50 connects the piston 20 to the crankshaft 60. The link 50 and the crankshaft 60 convert the reciprocating motion of the piston 20 into the rotation motion of the crankshaft 60. The crankshaft 60 drives the intake-exhaust assembly 42 to rotate. The crankshaft sprocket 70 is mounted on the crankshaft 60. The intake-exhaust sprocket 80 is mounted on the intake-exhaust mechanism 40. The chain 90 connects the crankshaft sprocket 70 to the intake-exhaust sprocket 80. In another example, a transmission mechanism, including gears, may also be adopted to replace the chain and the sprocket.
FIG. 4A shows a positional relationship between the inlet port 41 C and the intake channel 41A according to the first embodiment of the invention. As shown in FIG. 4A, an extension line EL1 of the intake channel 41A and an extension line EL2 of the inlet port 41C intersect each other in the chamber 41S. FIG. 4B shows a positional relationship between the outlet port 41D and the exhaust channel 41B according to the first embodiment of the invention. As shown in FIG. 4B, an extension line ED of the exhaust channel 41B and an extension line EL4 of the outlet port 41D intersect each other in the chamber 41S. With the above-mentioned structure, the travelling path of the compressed gas needs not to be turned from the radial direction to the axial direction, thereby decreasing the energy loss.
FIGS. 4C and 4D are schematic illustrations showing an intake state of the air engine at the same time instant according to the first embodiment of the invention. In FIGS. 4C and 4D, the intake stroke is depicted, wherein the compressed gas CA enters the intake passage 42B1 of the intake member 42B from the inlet port 41C. At this time, the intake passage 42B1 concurrently communicates with the inlet port 41C and the intake channel 41A, so that the compressed gas CA can enter the cylinder 10 in the path indicated by the arrow, and then push the piston 20 and thus push the crankshaft 60 through the link 50. The crankshaft 60 rotates the crankshaft sprocket 70, and thus rotates the intake-exhaust sprocket 80 through the chain 90. Also, the intake-exhaust sprocket 80 rotates the rotating shaft 42A so that the intake member 42B and the exhaust member 42C are rotated concurrently. In FIG. 4D, the exhaust passage 42C1 contains the exhaust gas EA, generated after the compressed gas CA expands to do the work. However, the exhaust passage 42C1 has not communicated with the outlet port 41D, so the exhaust gas EA cannot be exhausted yet. It is to be noted that the exhaust gas EA is different from the burned exhaust gas generated by the internal combustion engine, and is only termed in comparison with the compressed gas CA. Basically, the exhaust gas EA is also the clean gas with the lower energy for pushing the piston 20.
FIGS. 4E and 4F are schematic illustrations showing an exhaust state of the air engine at the same time instant according to the first embodiment of the invention.
In FIGS. 4E and 4F, the exhaust stroke is depicted, wherein the compressed gas CA cannot enter the intake channel 41A from the inlet port 41C, and the exhaust gas EA is exhausted from the exhaust channel 41B via the exhaust passage 42C1 of the exhaust member 42C and the outlet port 41D. In one example, the exhaust gas EA can be directly exhausted to the atmosphere environment, In another example, the exhaust gas EA may be exhausted to the atmosphere environment via an exhaust pipe (not shown) connected to the outlet port 41D. The exhaust pipe can reduce or eliminate the noise generated upon the expansion and work of the gas.
In this embodiment, the arc covered by the intake passage 42B1 is smaller than that covered by the exhaust passage 42C1, so the intake period is shorter than the exhaust period. In other embodiments, however, it is also possible to adjust the dimensions of the intake passage 42B1 and the exhaust passage 42C1 and the angular position of the intake passage 42B1 relative to the exhaust passage 42C1, so as to adjust the intake timing and the exhaust timing and increase the output power of the air engine 1.
FIG. 5A is a comparison chart showing a cylinder pressure ratio versus a cylinder volume in a conventional air engine and the air engine, both rotating at 800 rpm, according to the first embodiment of the invention, wherein the cylinder pressure ratio is the ratio of the pressure (P) in the cylinder to the maximum pressure (Pmax) in the cylinder the conventional air engine adopts the cams in conjunction with trumpet-shaped intake valves and exhaust valves, and the volume relates to the position of the piston. When the piston is at the top dead center, the volume in the cylinder reaches the minimum; and when the piston is at the bottom dead center, the volume in the cylinder reaches the maximum. As shown in FIG. 5A, the rising slope of the intake pressure ratio of the air engine of the invention is larger than that of the conventional air engine, and the falling slope of the intake pressure ratio of the air engine of the invention is also larger than the falling slope of the conventional air engine. So, the overall area enclosed by the pressure ratio-volume curve in the air engine of the invention is also larger, and this represents that the output indicated power of the air engine of the invention is higher than that of the conventional air engine. This means that the efficiency of the air engine can be effectively enhanced using the intake-exhaust mechanism of the invention.
FIG. 5B is a comparison chart showing openings of valves with respect to an intake timing and an exhaust timing, which correspond to the angle of the crankshaft, in the conventional air engine and the air engine according to the first embodiment of the invention. In FIG. 5B, the intake timing ranges from 0 to 160 degrees, the exhaust timing ranges from 170 to 360 degrees, the horizontal axis represents the angle of the crankshaft, the vertical axis represents the opening of the valve in percentage (%), the curve TCI represents the intake timing of the intake member of the invention and partially overlaps with the horizontal axis, the curve TC2 represents the exhaust timing of the exhaust member of the invention and partially overlaps with the horizontal axis, the curve TC3 represents the intake timing of the conventional intake valve and partially overlaps with the horizontal axis, and the curve TC4 represents the exhaust timing of the conventional exhaust valve and partially overlaps with the horizontal axis. As shown in FIG. 5B, it is obtained, from the curves TC1 and TC2, that the invention can achieve the maximum opening of the intake valve when the crankshaft angle is from about 10 degrees to about 150 degrees. Similarly, the invention can achieve the maximum opening of the exhaust valve when the crankshaft angle is from about 180 degrees to 350 degrees. According to the curves TC3 and TC4, it is obtained that the prior art only can obtain the effects of progressively opening and closing the valve. Thus, the invention can achieve the effects of instantaneously opening and closing the valves, thereby increasing the intake efficiency and the exhaust efficiency and thus the efficiency of the air engine. This cannot be achieved in the prior art.
In the first embodiment, the relative positional and angular relationships between the intake member 42B, the exhaust member 42C and the rotating shaft 42A are constant. However, in order to adjust the intake timing and the exhaust timing, an improved design may be made according to the following method. FIG. 6 is a schematic partial view showing an intake-exhaust assembly according to a second embodiment of the invention. Referring to FIG. 6, the intake-exhaust assembly 42 further includes a phase adjusting mechanism 42D, which is connected to the intake member 42B and the exhaust member 42C and adjusts the angular position of the intake member 42B relative to the exhaust member 42C to adjust the relative relationship between the intake timing and the exhaust timing. The phase adjusting mechanism 42D includes a nut 42D1 and a thread 42AT formed on the rotating shaft 42A. Thus, the nut 42D1 may be screwed to the rotating shaft 42A and mount the intake member 42B or the exhaust member 42C on the rotating shaft 42A in an adjustable manner. Accordingly, the adjuster can adjust the angular position of the nut 42D1 relative to the rotating shaft 42A to achieve the effect of adjusting the intake timing and the exhaust timing. Although four nuts 42D1, 42D2, 42D3 and 42D4 are used in FIG. 6, it should be noted that the angular position of one rotary member relative to the other rotary member can be adjusted using one single nut. That is, using one single nut 42D1 can mount the intake member 42B or the exhaust member 42C on the rotating shaft 42A in the adjustable manner.
FIG. 7 is a partial cross-sectional view showing an intake-exhaust assembly according to a third embodiment of the invention. As shown in FIG. 7, the rotating shaft 42A may also be coupled to the intake member 42B or the exhaust member 42C using a spline SP. The relative relationship between the intake timing and the exhaust timing is adjusted by adjusting the spline. That is, the rotating shaft 42A may be rotated relatively to the intake member 42B or the exhaust member 42C before the intake member 42B or the exhaust member 42C are mounted on the rotating shaft 42A through the spline SR
FIGS. 8A to 8C show three examples of intake-exhaust paths according to the invention. In the first embodiment, the included angle A1 between the inlet port 41C and the intake channel 41A is equal to 90 degrees, and the included angle A2 between the outlet port 41D and the exhaust channel 41B is also equal to 90 degrees, as shown in FIG. 8A. In another example, however, the included angles A1 and A2 are equal to 135 degrees. In still another example, the included angles A1 and A2 are equal to 180 degrees. It is to be noted that the included angle A1 may be designed to be unequal to the included angle A2 in order to adjust the efficiency.
FIGS. 9A to 9C show three examples of intake/exhaust passages of intake/exhaust members according to the invention. In the first embodiment, the profiles (or referred to as projection planes) of the intake passage 42B1 and the exhaust passage 42C1 are rectangular, as shown in FIG. 9A. In another example, the intake passage 42B1 and the exhaust passage 42C1 may have elliptical profiles (FIG. 9B) or funnel-like profiles (FIG. 9C). This represents that the shape design of the air passage may function as one of parameters for adjusting the efficiency of the air engine.
With the air engine of the invention, controlling the instantaneous open and close operations of the valves can provide more sufficient intake and exhaust for the engine to increase the efficiency. Because no cam is needed, no complicated mechanism has to be disposed, and no hysteresis phenomenon is caused upon the power transmission of the cam (especially at the high rotating speed). Because no fuel is provided and burned, no contaminated exhaust gas is generated, and no spark plug or high-pressure nozzle is needed to perform the ignition operation. Therefore, the air engine of the invention has the relatively high applicability and economy after the intake and exhaust strokes are improved.
While the present invention has been described by way of examples and in terms of preferred embodiments, it is to be understood that the present invention is not limited thereto. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications.

Claims

What is claimed is:

1. An air engine, comprising:

a cylinder;

a piston capable of reciprocating in the cylinder;

a gas supply supplying a compressed gas to move the piston; and

an intake-exhaust mechanism, which is connected to the cylinder and the gas supply and comprises:

a body having a chamber, and an intake channel, an exhaust channel, an inlet port and an outlet port, which communicate with the chamber, wherein the intake channel and the exhaust channel communicate with the chamber and the cylinder; and

an intake-exhaust assembly, which is rotatable within the chamber, controls the inlet port to be connected to the intake channel or not upon rotation, and controls the outlet port to be connected to the exhaust channel or not upon rotation, so that the compressed gas enters the cylinder via the inlet port and the intake channel to drive the piston, wherein after driving the piston, the compressed gas becomes an exhaust gas, which is exhausted from the cylinder via the exhaust channel and the outlet port.

2. The air engine according to claim 1, wherein the intake-exhaust assembly comprises:

a rotating shaft;

an intake member, which is disposed on the rotating shaft and has an intake passage that can communicate with the inlet port and the intake channel; and

an exhaust member, which is disposed on the rotating shaft and has an exhaust passage that can communicate with the outlet port and the exhaust channel.

3. The air engine according to claim 2, wherein the intake-exhaust assembly further comprises a phase adjusting mechanism, which is connected to the intake member and the exhaust member, adjusts an angular position of the intake member relative to the exhaust member, and adjusts a relative relationship between an intake timing and an exhaust timing.

4. The air engine according to claim 3, wherein the phase adjusting mechanism comprises:

nuts, which are screwed to the rotating shaft and mount the intake member or the exhaust member on the rotating shaft in an adjustable manner.

5. The air engine according to claim 3, wherein the phase adjusting mechanism comprises:

a nut, which is screwed to the rotating shaft and mounts the intake member or the exhaust member on the rotating shaft in an adjustable manner.

6. The air engine according to claim 2, wherein the rotating shaft is coupled to the intake member or the exhaust member with a spline, and a relative relationship between an intake timing and an exhaust timing is adjusted by adjusting the spline.

7. The air engine according to claim 1, wherein extension lines of the intake channel and the inlet port intersect each other in the chamber.

8. The air engine according to claim 1, wherein an included angle between the inlet port and the intake channel is unequal to an included angle between the outlet port and the exhaust channel.

9. The air engine according to claim 1, further comprising a link and a crankshaft, wherein the link connects the piston to the crankshaft and converts reciprocating motion of the piston into rotary motion of the crankshaft, and the crankshaft drives the intake-exhaust assembly to rotate.

10. The air engine according to claim 9, further comprising:

a crankshaft sprocket mounted on the crankshaft;

an intake-exhaust sprocket mounted on the intake-exhaust mechanism; and

a chain connecting the crankshaft sprocket to the intake-exhaust sprocket.