The present invention relates to an improvement to a reciprocating, internal combustion engine with a heat exchanger.
The four ways to improve the most popular engine in use today are: 1. separating the compression from the expansion process, 2. compressing at almost constant temperature, 3. saving the exhaust heat and use it to heat the compressed air, and 4. changing the engine displacement to match the load while the engine runs.
The first three ways, separating the compression from the expansion process, compressing at almost constant temperature, and saving the exhaust heat and using it to heat the compressed air, were the subject of U.S. patent application Ser. Nos. 10/656,317 filed on Sep. 8, 2003 and 10/700,421 filed on Nov. 5, 2003.
The fourth way is the subject of this patent.
The fourth way, changing the engine displacement as the engine runs to match the load, is the subject of this invention.
The improvement is accomplished by adding compressed air storage container 36, movable wall 11, fixed stop 6, bias spring 38, adjustable stop 40, adjustable stop controller 44, telescoping connecting rod 25, and pusher piston 15, to an internal combustion engine with a heat exchanger.
In the resulting engine when power piston 14 reaches the top of its travel, compressed air from compressed air storage container 36 moves through heat exchanger high-pressure side 8 and on into cylinder 12. Pressure on both sides of movable wall 11 is the same; therefore, bias spring 38 is provided to move movable wall 11. Adjustable stop controller 44 controls the position of adjustable stop 40. Adjustable stop 40 allows the desired amount of compressed air into cylinder 12. When the desired amount of air is in cylinder 12, pusher piston 15 pushes power piston 14 back up to the top of its travel, inlet valve 10 closes, fuel is then added, burned, and expanded. When pressure in cylinder 12 decreases, movable wall 11 moves back down against fixed stop 6 as expansion continues.
Telescoping connecting rod 25 allows pusher piston 15 to push power piston 14 back up. When the engine is set for very small displacement, telescoping connecting rod 25 also allows pusher piston 15 to go all the way to the bottom of cylinder 12 while power piston 14 does not go all the way to the bottom.
At low power, the engine can operate on an engine cycle where compression is cooled, heat is added at constant pressure, combustion heat is added at near constant temperature, and the exhaust heat is captured and returned to the compressed air. This results in an engine that operates on a perfect thermodynamic cycle.
At higher power, the engine can operate on an engine cycle where compression is cooled, heat is added at constant pressure, combustion heat is added at near constant volume, and the exhaust heat is captured and returned to the compressed air. The result is an engine that operates on a little less than perfect thermodynamic cycle, but with higher power output.
The “Improved Internal Combustion Engine with Heat Exchanger” has the following advantages:
It can operate on a perfect thermodynamic cycle.
If heat is added to the compressed air at constant volume instead of constant temperature, then more work can be done with the heat that is added.
It changes the amount of air expanded by the engine to match the engine power to the load requirements.
When the load slows down it can save the inertia work and reuse it.
2 air intake
3 air intake port
4 compressor
5 compressor exit valve
6 fixed stop
7 low power air intake port
8 heat exchanger high-pressure side
10 inlet valve
11 movable wall
12 cylinder
14 power piston
15 pusher piston
16 cylinder head
18 fuel injector
20 igniter
22 power output shaft
24 connecting rod
25 telescoping connecting rod
26 valve push rods
28 valve cams
30 exit valve
32 heat exchanger low-pressure side
34 exhaust exit
36 compressed air storage container
38 bias spring
40 adjustable stop
44 adjustable stop controller
46 lower compressor valve
48 cooler
50 upper compressor valve
51 displacer
52 compressor piston
53 displacer cam follower
54 compressor piston cam follower
55 second cooler
56 cam
57 low power valve
The preferred embodiment of this invention is the addition of fixed stop 6, moveable wall 11, pusher piston 15, telescoping connecting rod 25, compressed air storage container 36, bias spring 38, adjustable stop 40, and adjustable stop controller 44 to an internal combustion engine with a heat exchanger.
The resulting engine is an internal combustion, reciprocating, regenerated engine made up of air intake 2, compressor 4, compressor exit valve 5, compressed air storage container 36, heat exchanger high-pressure side 8, power output shaft 22, heat exchanger low-pressure side 32, exhaust exit 34, and one or more similar working units. Each working unit is comprised of cylinder 12, which contains fixed stop 6, inlet valve 10, movable wall 11, power piston 14, pusher piston 15, cylinder head 16, fuel injector 18, igniter 20, connecting rod 24, telescoping connecting rod 25, valve push rods 26, valve cams 28, exit valve 30, bias spring 38, adjustable stop 40, and adjustable stop controller 44.
The engine has only one each of air intake 2, compressor 4, compressor exit valve 5, compressed air storage container 36, heat exchanger high-pressure side 8, heat exchanger low-pressure side 32, and exhaust exit 34, but it can have many working units.
To obtain maximum efficiency the compressor should operate as close to constant temperature as possible. For example, using a multi-stage-intercooled compressor with the number of stages determined by the pressure ratio of the compressor.
The airflow control is shown using check type valves and poppet type valves. These could be replaced with other type flow control devices.
Compressed air storage container 36 can also be an accumulator.
Although the air coming out of the heat exchanger high-pressure side 8 may be hot enough to ignite the fuel, igniter 20 is shown in all figures because it is needed to start the engine.
FIGS. 1 to 6 present the sequence of steps or processes occurring in cylinder 12. All six figures indicate that air has been taken in through air intake 2, compressed by compressor 4, stored in compressed air storage container 36, and heated going through heat exchanger high-pressure side 8 by exhaust gases flowing through heat exchanger low-pressure side 32 on their way to exhaust exit 34.
Between
Between
Between
Between
Between
Between
The cycle repeats.
During the above cycle adjustable stop 40 is moved to allow more or less compressed air into cylinder 12 and is controlled by adjustable stop controller 44. When more compressed air is let into cylinder 12 more power is produced. When less compressed air is let into cylinder 12 less power is produced.
The inertia from the load slowing down can be used to continue to compress air. As the engine uses less than is compressed, the extra air is stored in compressed air storage container 36. The extra air that is stored in compressed air storage container 36 can be used to allow the engine to operate at high power.
The first alternate embodiment of this invention is the preferred embodiment of this invention with the addition of low power valve 57 and the removal of pusher piston 15 and telescoping connecting rod 25.
The resulting engine is an internal combustion, reciprocating, regenerated engine made up of air intake 2, compressor 4, compressor exit valve 5, compressed air storage container 36, heat exchanger high-pressure side 8, power output shaft 22, heat exchanger low-pressure side 32, exhaust exit 34, and one or more similar working units. Each working unit is comprised of cylinder 12, which contains fixed stop 6, inlet valve 10, movable wall 11, power piston 14, cylinder head 16, fuel injector 18, igniter 20, connecting rod 24, valve push rods 26, valve cams 28, exit valve 30, bias spring 38, adjustable stop 40, and adjustable stop controller 44.
The engine has only one each of air intake 2, compressor 4, compressor exit valve 5, compressed air storage container 36, heat exchanger high-pressure side 8, heat exchanger low-pressure side 32, and exhaust exit 34, but it can have many working units.
To obtain maximum efficiency the compressor should operate as close to constant temperature as possible. For example, use a multi-stage-intercooled compressor with the number of stages determined by the pressure ratio of the compressor.
The airflow control is shown using check type valves and poppet type valves. These could be replaced with other type flow control devices.
Compressed air storage container 36 can also be an accumulator.
Although the air coming out of the heat exchanger high-pressure side 8 is hot enough to ignite the fuel, igniter 20 is shown in all figures because it is needed to start the engine.
FIGS. 7 to 11 present the sequence of steps or processes occurring in cylinder 12. All the figures indicate that air has been taken in through air intake 2, compressed by compressor 4, stored in compressed air storage container 36, and heated going through heat exchanger high-pressure side 8 by exhaust gases flowing through heat exchanger low-pressure side 32 on their way to exhaust exit 34.
Between
Between
Between
Between
Between
The cycle repeats.
Adjustable stop 40 is moved to allow more or less compressed air into cylinder 12 and is controlled by adjustable stop controller 44. When more compressed air is let into cylinder 12 more power is produced. When less compressed air is let into cylinder 12 less power is produced.
The inertia from the load slowing down can be used to continue to compress air. As the engine uses less than is compressed the extra air is stored in compressed air storage container 36. The extra air that is stored in compressed air storage container 36 can be used to allow the engine to operate at high power.
The second alternate embodiment of this invention is the preferred embodiment of this invention with the addition of air intake port 3, low power air intake port 7, lower compressor valve 46, cooler 48, upper compressor valve 50, displacer 51, compressor piston 52, displacer cam follower 53, compressor piston cam follower 54, second cooler 55, cam 56, and low power valve 57 and the removal of compressor 4, pusher piston 15 and telescoping connecting rod 25.
The resulting engine is an internal combustion, reciprocating, regenerated engine made up of compressed air storage container 36, second cooler 55, heat exchanger high-pressure side 8, power output shaft 22, heat exchanger low-pressure side 32, exhaust exit 34, adjustable stop controller 44, and one or more similar working units. Each working unit is comprised of cylinder 12 that is closed at one end by cylinder head 16. Air intake 2 and air intake port 3 allow air into cylinder 12 at higher power. At low power, low power valve 57 and low power air intake port 7 allow air into cylinder 12. Inside or attached to cylinder 12 are, compressor piston 52, movable wall 11, bias spring 38, adjustable stop 40, fixed stop 6, fuel injector 18, igniter 20, cooler 48, power piston 14, and connecting rod 24. Connecting rod 24 is connected to power output shaft 22, which operates cam 56 and valve cams 28. Valve push rods 26 are moved by valve cams 28. Compressor piston 52 is moved by cam 56 using compressor piston cam follower 54. Displacer 51 is moved by cam 56 using displacer cam follower 53. Lower compressor valve 46 and upper compressor valve 50 control the flow of air through cooler 48. Second cooler 55, compressed air storage container 36, and heat exchanger high-pressure side 8 are attached to cylinder 12 between compressor exit valve 5 and inlet valve 10. Exit valve 30 allows exhaust into heat exchanger low-pressure side 32 and out exhaust exit 34.
The compressor cooling system is made up of compressor piston 52, compressor piston cam follower 54, a grove in cam 56, cooler 48, lower compressor valve 46, and upper compressor valve 50. Cooler 48 cools the air as it is being compressed. Lower compressor valve 46 and upper compressor valve 50 control the air flow through cooler 48. The engine will operate without any compressor cooling systems. As many compressor cooling systems as desired may be added to the engine. The more compressor cooling systems an engine has, the closer its compression equals constant temperature compression.
The thickness of displacer 51 can be such that the compression and the expansion volumes are separated. The heat from one does not effect the other.
The engine is shown with power output shaft 22 transferring power out of the engine. Other means such as a wobble plate could be used to transfer power from the engine.
The engine is shown with cam 56 moving compressor piston 52 and displacer 51. Other means such as an actuator could move compressor piston 52 and displacer 51.
The engine is shown with poppet type valves. Other type valves could be used.
Compressed air storage container 36 can also be an accumulator.
Although the air coming out of the heat exchanger high-pressure side 8 is hot enough to ignite the fuel, igniter 20 is shown in all figures because it is needed to start the engine.
The second alternate embodiment employs a two-stroke cycle, divided into four parts. The first part is the air intake part, the second is the cooled compression part, the third is the heat recovery part, and the fourth is the heated expansion part. The air intake part is from about 85% of the downward travel of power piston 14 to about 15% of the travel back up (or as measured by power output shaft 22 rotation from about 135° to about 225°). The cooled compression part is from about 15% of the travel back up of power piston 14 (225°) to about 75% of the travel back up of power piston 14 (300°). The heat recovery part is from about 75% of the travel back up of power piston 14 (300°) to about top dead center of power piston 14 (0°). The heated expansion part is from about top dead center of power piston 14 (360°) to about 85% of the downward travel of power piston 14 (135°).
The above positions are all estimates and are given for descriptive purposes only. The actual position a part of the cycle may begin or end at may be different from those set out above.
FIGS. 12 to 17 present the sequence of steps or processes occurring in the engine. The air intake part of the cycle takes place between
Between
Between
Between
Between
Between
Between
Conclusion
From the above, it can be determined that the “Improved Internal Combustion Engine with Heat Exchanger” has the following advantages:
Operating on a constant temperature compression, constant pressure heating and expansion, constant temperature expansion, and constant pressure cooling cycle, Carnot cycle efficiency can almost be attained at any temperature, compression ratio, speed, or heat exchanger volume.
If in the above cycle heat is added to the hot compressed air at constant volume instead of constant temperature, then more work can be done with the heat that is added.
It changes the amount of air expanded by the engine to match the engine power to the load requirements.
When the load slows down it can save the inertia work and reuse it.
The compression and the expansion volumes can be separated. The heat from one will not effect the other.