Shown in Fig.6 and Fig.7, is a third embodiment of a valve actuator 41 according to the present invention. This embodiment includes a curved insulating element 91 having it's first end able to pivot, being secured by any suitable device such as screw 92 to the shaft 55 for co-rotation with the shaft 55. The screw 92 is screwed into a tapped hole in the insulating element 91 so that a tab 94 at an end of the screw 92 engages a groove 96 provided in the shaft 55. In this way, the insulating element 91 rotates positively with the shaft 55. However, as the shaft 55 rotates faster, the other end 98 of the insulating element 91 is permitted to pivot outwards under the influence of centrifugal force because of the groove 96 provided in the shaft 55. A spring 93, connected between the second end 98 of the element 91 and the shaft 55 urges the second end of the element 91 towards the centre of the housing 53.
A contact 99 similar to the contact 59 (Fig.2) is arranged so that one end of the contact piece 99 is in constant contact with the conducting plate 51 located centrally within the housing 53. The other end of the contact 99 engages a conductive sleeve 101 arranged in bore 102. A contact element 95 is arranged in the conductive sleeve 101 in constant contact with the sleeve 101. The bore 102 is arranged generally parallel to the shaft 55 near the second end of the curved insulating element 91. The contact 95 is biased by a spring 97 towards the upper inside surface of the housing 53 for selective contact with each of the plurality of radial contacts 85 which increase in arc length towards the outer peripheral surface of the housing 53 (Fig.6).
When the device shown in Fig.6 and Fig.7 is operating, as the shaft 55 rotates the curved insulating element 91 rotates with the shaft 55 and the second end 98 of the insulating element 91 tends to pivot about the shaft 55 due to centrifugal force. Thus, as the effective length of the contact 95 increases, i.e., as the curved insulating element 91 pivots further outwards, the number of degrees of rotation over which the contact 95 is in contact with each of the radial contacts 85 on the upper inside surface of the housing 53 increases thereby allowing each of the valves 39 to remain open for a longer period of each engine cycle, which in turn, allows more compressed gas enter the respective cylinder 20 to further increase the speed of the engine 21.
With reference to Fig.1, a mechanical advance linkage 104 which is connected to the throttle linkage 35, advances the initiation of the opening of each valve 39 such that compressed gas is injected into the respective cylinder further before the piston 22 in the respective cylinder 20 reaches a Top Dead Centre position as the speed of the engine is increased by moving the throttle linkage 35. The advance linkage 104 is similar to a conventional standard mechanical advance employed on an internal combustion engine. In other words, the linkage 104 varies the relationship between the angular positions of a point on the shaft 55 and a point on the housing 53 containing the contacts. Alternatively, a conventional vacuum advance could also be employed. By advancing the timing of the opening of the valves 39, the speed of the engine can more easily be increased.
The operation of the engine cycle according to the present invention will now be described. The compressed gas injected into each cylinder of the engine 21 drives the respective piston 22 downwards to rotate a conventional crankshaft (not shown). The movement of the piston downwards causes the
compressed gas to expand rapidly and cool. As the piston 22 begins to move upwards in the cylinder 20 a suitable exhaust valve (not shown), arranged to close an exhaust passageway, is opened by any suitable apparatus. The expanded gas is then expelled through the exhaust passageway. As the piston 22 begins to move downwards again, a suitable intake valve opens to admit ambient air to the cylinder. The intake valve closes and the ambient air is compressed on the subsequent upward movement of the piston until the piston reaches approximately the Top Dead Centre position at which time the compressed gas is again injected into the cylinder 20 to drive the piston 22 downwards and the cycle begins again.
In the case of adapting a conventional internal combustion engine for operation on compressed gas, a plurality of plates 103 are arranged, preferably over an end of the exhaust passageways, in order to reduce the outlet size of the exhaust passageways of the conventional internal combustion engine. In the illustrated embodiment, a single plate having an opening in the centre is bolted to the outside exhaust passageway on each bank of the V-8 engine, while another single plate having two openings in it, is arranged with one opening over each of the interior exhaust passageways on each bank of the V-8 engine. A line 105 is suitably attached to each of the adaptor plates to carry the exhaust to an appropriate location. In a preferred embodiment, the exhaust lines 105 are made from 1.5" plastic tubing.
In a preferred embodiment, the exhaust lines 105 of one bank of the V-8 engine are collected in a line 107 and fed to an inlet of a compressor 109. The pressure of the exhaust gas emanating from the engine 21 according to the present invention is approximately 25 p.s.i. In this way, the compressor 109 does not have to pull the exhaust into the compressor since the gas exhausted from the engine 21 is at a positive pressure. The positive pressure of the incoming fluid increases the efficiency and reduces wear on the compressor 109. The exhaust gas is compressed in the compressor 109 and returned through a line 111 and a check valve 113 to the compressed gas storage tank 23. The check valve 113 prevents the flow of compressed gas stored in the tank 23 back towards the compressor 109.
A suitable pressure sensor 115 is arranged at an upper end of the tank 23 and sends a signal along a line 117 when the pressure exceeds a predetermined level and when the pressure drops below a predetermined level. The line 117 controls an electrically activated clutch 119 positioned at the front end of the compressor 109. The clutch 119 is operated to engage and disengage the compressor 109 from a drive pulley 121. Also, the signal carried by the line 117 activates a suitable valve 123 arranged on compressor housing 125 to exhaust the air entering the compressor housing 125 from the line 107 when the clutch 119 has disengaged the compressor 109 from the drive pulley 121.
In a preferred embodiment, when the pressure is the tank 23 reaches approximately 600 p.s.i., the clutch 119 is disengaged and the compressor 109 is deactivated and the valve 123 is opened to exhaust the expanded gas delivered to the compressor 109 from the line 107 to the atmosphere. When the pressure within the tank 23 drops below approximately 500 p.s.i., the sensor 115 sends a signal to engage the clutch 119 and close the valve 123, thereby operating the compressor 109 for supplying the tank 23 with compressed gas.
The pulley 121 which drives the compressor 109 through the clutch 119 is driven by a belt 127 which is driven by a pulley 129 which operates through a gear box 131. With reference to Fig.1 and Fig.8, a second pulley 133 on the gear box is driven by a belt 135 from a pulley 137 arranged on a drive shaft 139 of the engine 21. The pulley 137 drives a splined shaft 140 which has a first gear 141 and a second larger gear 143 placed on it, which rotates with the splined shaft 140. The splined shaft 140 permits axial movement of the gears 141 and 143 along the shaft 140.
In normal operation (as seen in Fig.8), the first gear 141 engages a third gear 145 arranged on a shaft 147 which drives the pulley 129. The shafts 140 and 147 are arranged in suitable bearings 149 positioned at each end of it. When the speed of the engine 21 drops below a predetermined level, a suitable sensor 151 responsive to the speed of the drive shaft 139 of the engine 21 generates a signal which is transmitted through a line 153 to a solenoid actuator 155 arranged within the gear box 131. The solenoid actuator 155 moves the first and second gears 141, 143 axially along the splined shaft 140 to the right as seen in Fig.8 so that the second, larger gear 143 engages a fourth smaller gear 157 which is arranged on the shaft 147. The ratio of the second gear 143 to the fourth gear 157 is preferably approximately 3 to 1.
In this way, when the speed of the engine 21 drops below the predetermined level as sensed by the sensor 151 (which predetermined level is insufficient to drive the compressor 109 at a speed sufficient to generate the 500-600 pounds of pressure which is preferably in the tank 23), the solenoid actuator 155 is energised to slide the gears 143, 141 axially along the splined shaft 140 so that the second, larger gear 143 engages the fourth, smaller gear 157 to drive the pulley 129 and hence the compressor 109 at a higher rate, to generate the desired pressure. When the speed of the engine increases above the predetermined level, which, in a preferred embodiment is approximately 1500 rpm, the solenoid actuator 155 is deactivated by the sensor 151 thereby moving the gears 143 and 141 to the left as seen in Fig.8 so that the first gear 141, engages again with the third gear 145 to effectuate a 1 to 1 ratio between the output shaft 139 of the engine 21 and the pulley 129.
The other bank of the V-8 engine has its exhaust ports arranged with adapter plates 103 similar to those on the first bank. However, the exhaust from this bank of the engine 21 is not collected and circulated through the compressor 109. In a preferred embodiment, a portion of the exhaust is collected in a line 159 and fed to an enlarged chamber 161. A second fluid is fed through a line 163 into the chamber 161 to be cooled by the cool exhaust emanating from the engine 21 in the line 159. The second fluid in the line 163 may be either transmission fluid contained in a transmission associated with the engine 21 or a portion of the oil used to lubricate the engine 21. A second portion of the exhaust from the second bank of the V-8 engine is removed from the line 159 in a line 165 and used as a working fluid in an air conditioning system or for any other suitable use.
It should be noted that the particular arrangement utilised for collecting and distributing the gas exhausted from the engine 21 would be determined by the use for which the engine is employed. In other words, it may be advantageous to rearrange the exhaust tubing such that a larger or smaller percentage of the exhaust is routed through the compressor 109. It should also be noted that since the exhaust lines 105 are plastic tubing, a rearrangement of the lines for a different purpose is both simple and inexpensive.
In operation of the engine of the present invention, the engine 21 is started by energising the solenoid valve 29 and any suitable starting device (not shown), e.g., a conventional electric starter as used on an internal combustion engine. Compressed gas from the full tank 23 flows through the line 25 and a variable amount of the compressed gas is admitted to the distributor 33 by controlling the regulator valve 31 through the linkage 33 and the operator actuated throttle linkage 35. The compressed gas is distributed to each of the lines 37 which lead to the individual cylinders 20. The compressed gas is admitted to each of the cylinders 20 in timed relationship to the position of the pistons within the cylinders by opening the valves 39 with the valve actuator 41.
When it is desired to increase the speed of the engine, the operator moves the throttle linkage 35 which simultaneously admits a larger quantity of compressed gas to the distributor 33 from the tank 23 by further opening the regulator valve 31. The timing of the valve actuator 41 is also advanced through the linkage 104. Still further, as the speed of the engine 21 increases, the effective length of the rotating contact 83 (Fig.4) or 95 (Fig.6) increases thereby electrically contacting a wider portion of one of the stationary radial contacts 85 to cause each of the valves 39 to remain open for a longer period of each engine cycle to admit a larger quantity of compressed gas to each of the cylinders 20.
As can be seen, the combination of the regulating valve 31, the mechanical advance 104, and the valve actuator 41, combine to produce a compressed gas engine which is quickly and efficiently adaptable to various operating speeds. However, all three of the controls need not be employed simultaneously. For example, the mechanical advance 104 could be utilised without the benefit of one of the varying valve actuators 41 but the high speed operation of the engine may not be as efficient. By increasing the duration of each engine cycle over which each of the valves 39 remains open to admit compressed gas to each of the cylinders 20 as the speed increases, conservation of compressed gas during low speed operation and efficient high speed operation are both possible.
After the compressed gas admitted to the cylinder 20 has forced the piston 22 downwards within the cylinder to drive the shaft 139 of the engine, the piston 22 moves upwards within the cylinder 20 and forces the expanded gas out through a suitable exhaust valve (not shown) through the adapter plate 103 (if employed) and into the exhaust line 105. The cool exhaust can then be collected in any suitable arrangement to be compressed and returned to the tank 23 or used for any desired purpose including use as a working fluid in an air conditioning system or as a coolant for oil.
When using the apparatus and method of the present invention to adapt a ordinary internal combustion engine for operation with compressed gas it can be seen that considerable savings in weight are achieved. For example, the ordinary cooling system including a radiator, fan, hoses, etc. can be eliminated since the compressed gas is cooled as it expands in the cylinder. In addition, there are no explosions within the cylinder to generate heat. Further reductions in weight are obtained by employing plastic tubing for the lines which carry the compressed gas between the distributor and the cylinders and for the exhaust lines. Once again, heavy tubing is not required since there is little or no heat generated by the engine of the present invention. In addition, the noise generated by an engine according to the present invention is considerably less than that generated by an ordinary internal combustion engine since there are no explosions taking place within the cylinders.
The principles of preferred embodiments of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. The embodiments are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the spirit of the invention. Accordingly, it is expressly intended that all such variations and changes which fall within the spirit and the scope of the present invention as defined in the appended claims be embraced thereby.
This patent shows how the practical details of running an engine on compressed air can be dealt with. What it does not show is background details of the actual energy flows and the effects of compressing air and then letting it expand. These things are not normally encountered in our daily lives and so we do not have an immediate intuitive feel for how a system like these will operate. Take the effects of expansion. While it is quite well known that letting a compressed gas expand causes cooling, the practical effect is seldom realised.
The web site http://www.airtxinternational.com/how vortex tubes work.php show the details of a "vortex tube" which is a completely passive device with no moving parts:
This device does things which you would not expect. Compressed air at a temperature of, say, seventy degrees Centigrade is fed into the circular chamber where the shape of the chamber causes it to spiral rapidly as it exits the tube:
There is an energy gain in a vortex, as can be seen in a hurricane or tornado, but the really interesting thing here is the dramatic change in temperature caused by the change in pressure as the air expands. The ratio of heat gain to heat loss is controlled by the ratio of the sizes of the openings, which is why there is an adjustable nozzle on the small opening.
The air exiting through the large opening is much higher volume than the air exiting through the small opening and it expands very rapidly, producing a massive drop in temperature. The density of this cold air is now much higher than the air entering the vortex chamber. So there has been both a drop in temperature and an increase in density. These features of the expansion are made use of in the Leroy Rogers engine design, where some of the expanded air exhaust of the engine is compressed and passed back to the main air storage tank. While the compressor does raise the air temperature as it pumps the air back into the tank, it does not reach its original temperature instantly.
This results in the air temperature inside the tank dropping as the engine operates. But, the lowered tank temperature causes an inflow of heat from its immediate environment, raising the overall tank temperature again. This warming of the chilled air causes the tank pressure to increase further, giving an energy gain, courtesy of the local environment. It is important to understand that it takes less energy to compress air than the kinetic energy which can be generated by letting that compressed air expand again. This is a practical situation, courtesy of the local environment and is not a breach of the law of Conservation of Energy. It is also a feature which has not yet been exploited to any great degree and which is just waiting to be used by any adventurous inventor or experimenter.
Eber presents a custom engine based on these principles. His engine uses both compressed air and compressed oil to manipulate pressures within the system and provide an engine which is self-powered. Here is a slightly re-worded copy of the Eber Van Valkinburg patent:
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