Not Applicable.
1. The Field of the Invention
The present invention relates generally engines, and more particularly, but not necessarily entirely, to internal combustion engines having pistons with a variable stroke length.
2. Description of Related Art
Internal combustion engines with reciprocating pistons are commonly used for powering automobiles. A break-away side view of a prior art engine, indicated generally at 1, is shown in FIG. 22. As is known in the art of internal combustion engines, pistons 2 are received in cylinders 3 and are caused to reciprocate in a direction parallel with the cylinders 3 along the movement axis 4 upon the combustion of fuel within the cylinders 3. Connecting rods 5 are attached to the pistons 2 and to a crankshaft 6. The movement of the pistons 2 is transferred to the crankshaft 6 through the connecting rods 5. The crankshaft 6 customarily extends in a direction along a rotation axis 7 that is perpendicular to the piston movement axis 4. Moreover, as the pistons 2 move along the movement axis 4, the connecting rods 5 move a fixed radial distance 8 from the axis of rotation 7 of the crankshaft 6.
The pistons 2 have a stroke length correlated with the radial distance 8. The stroke length extends between a top dead center position, or the position at which a piston reaches the top of its travel, to the bottom dead center position, or the extreme bottom of the piston stroke. Internal combustion engines are commonly designed with a fixed stroke length and may be configured to provide maximum operating efficiency at a given throttle position. Accordingly, when the engine is not operating at that given throttle position, the engine will be less efficient, resulting in wastage of fuel or diminished power output, for example.
Moreover, the range of output capabilities is fixed in the prior art engine so that the engine may not be well suited for variable operational needs. For example, engines are commonly built with a specific purpose in mind. Some engines are built to produce economical transportation. These engines are commonly associated with low power capabilities. Other engines may be manufactured to produce high performance and high speeds. These engines are commonly associated with low fuel mileage. Other engines are produced with high towing power in mind. These engines may not be suitable for high speed functions or high fuel economy. Accordingly, the prior art engines have experienced a compromise between such operational features as economy and power.
It is known in the art to vary the stroke length of the piston to modify the operating characteristics of the internal combustion engine. For example, U.S. Pat. No. 5,927,236 (granted Jul. 27, 1999 to Gonzalez) discloses a variable stroke mechanism for internal combustion engines utilizing gear sets to modify the length of the connecting rod. The mechanism is designed to increase the efficiency of the engine by imposing a larger expansion stroke and a shorter intake stroke. However, the gear sets increase the complexity and cost of the engine, and make operation and repair more difficult.
Also, U.S. Pat. No. 5,136,987 (granted Aug. 11, 1992 to Schechter et al.) discloses a variable displacement and compression ratio piston engine. A connecting rod is attached to the piston and a swing plate. The swing plate is pivotally fixed to the engine block at one end and is placed between the connection rod and a crankshaft. A hydraulically controlled adjustment link is pivotally fixed to the engine block at one end and to the connecting rod and the swing plate at the other end. The connecting rod and crankshaft are attached to the swing plate through slots in the swing plate such that the hydraulically controlled adjustment link can vary the distance between the piston and the crankshaft to thereby vary the stroke length. However, the sliding action of the connecting rod and the crankshaft in the slots in the swing plate may cause undue friction and wear in the engine.
The prior art is thus characterized by several disadvantages that are addressed by the present invention. The present invention minimizes, and in some aspects eliminates, the above-mentioned failures, and other problems, by utilizing the methods and structural features described herein.
It would therefore be an advancement in the prior art to provide an engine that allows for adjustment of the operational characteristics of the engine in a simple manner, so that the engine is not required to compromise between power and economy. It would also be an improvement in the prior art to provide such an engine that allows for adjustment of the radial distances between the connecting rod and the axis of rotation of the crankshaft to thereby provide a variable stroke length of the piston. It would be a further advancement in the art to provide such an engine that provides for adjustment of the piston stroke length by allowing the axis of rotation of the crankshaft to extend at a non-perpendicular angle with respect to the movement axis of the piston. It would be an additional advancement over the prior art variable-stroke engine crankshafts, which typically include moving parts, to provide a variable-stroke engine having a solid crankshaft with no moving parts, which would be less prone to failure or to require excessive maintenance.
The features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the invention without undue experimentation. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.
The features and advantages of the invention will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which:
a is a break-away side view of an embodiment of an engine made in accordance with the principles of the present invention with the piston in a long stroke, bottom dead center position;
b is a break-away side view of the embodiment of
c is a break-away side view of the embodiment of
d is a break-away side view of the embodiment of
e is a break-away side view of a curved journal portion embodiment of the invention with the piston in a long stroke, top dead center position;
f is a break-away side view of an embodiment of the invention configured to maintain a constant distance from the head to the piston at the top dead center position;
a is a break-away side view of an alternative embodiment of the present invention having two pistons in a long stroke bottom dead center position;
b is a break-away side view of the embodiment of
c is a break-away side view of the embodiment of
d is a break-away side view of the embodiment of
a is a break-away side view of an alternative embodiment of the present invention having multiple journal portions and four pistons;
b is a break-away side view of the embodiment of
a is a break-away side view of an alternative embodiment of the present invention having multiple journal portions and a crankshaft without universal connections;
b is a break-away side view of an alternative embodiment of the present invention having multiple journal portions and a crankshaft without universal connections supported by bearing holding means;
a is a break-away side view of the embodiment of
b is a break-away side view of the embodiment of
c is a break-away side view of the embodiment of
d is a break-away side view of the embodiment of
e is a break-away side view of the embodiment of
a is a perspective view of an engine block having six cylinders in a circular pattern and an angled crankshaft;
c is an end view of the engine block of
a is a top view of a piston;
b is a top view of an alternative embodiment piston;
a is a cross-section of an embodiment of the journal portion;
b is a cross-section of an alternative oblong embodiment journal portion;
c is a cross-section of an alternative triangular embodiment journal portion;
d is a cross-section of an alternative square embodiment journal portion;
e is a cross-section of an alternative embodiment rectangular journal portion;
f is a cross-section of an alternative embodiment “I” beam journal portion;
For the purposes of promoting an understanding of the principles in accordance with the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention claimed.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Moreover, as used herein, the terms “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps.
As used herein the term “compression ratio” refers to the ratio of the maximum to the minimum volume within the cylinder, between the piston and cylinder head, in accordance with the customary usage of the term “compression ratio” by those skilled in the art.
Referring now to
The crankshaft 22 may have a first end portion 24 that may be received in a first side support 26 on the engine 10, such that the first end portion 24 is permitted to rotate with respect to the first side support 26 about a first axis of rotation 28. The crankshaft 22 may also include a second end portion 30 opposite the first end portion 24. The second end portion 30 may be supported on a second side support 32 in a manner similar to the first end portion 24, and may be configured to be parallel with the first end portion 24. It will be understood that the first end portion 24 may be coaxial with the second end portion, as shown in
The first end portion 24 and the second end portion 30 may each include a universal connection 36, also sometimes referred to as a universal joint, attached to an angled segment 38 of the crankshaft 22. Stated another way, a universal connection 36 intercouples the angled segment 38 with the first end portion 24, and another universal connection 36 intercouples the angled segment 38 with the second end portion 24. As shown most clearly in
The angled segment 38 may include a third axis of rotation 54, also referred to herein as an angled segment axis of rotation, extending between the first end 50 of the angled portion 38 to the second end 52 of the angled portion 38. The angled segment 38 may also include a journal portion 56 between the first end 50 and the second end 52. The journal portion 56 may be configured to form an angle that is non-perpendicular with the movement axis 58 of the piston 18. In the embodiment shown in
A line that is perpendicular with the movement axis 58 of the piston 18 is depicted as shown at reference numeral 60. The third axis of rotation 54 may extend at an angle θ from the line 60 selected to provide optimal operating characteristics of the engine 10 based on numerous variables such as fuel type, fuel grade, temperature, and pressure. The angle θ between the third axis of rotation 54 and the line 60 may also be selected to provide a desired compression ratio, and to allow the stroke length to be changed without causing the piston 18 to contact the engine head 16. The orientation of the third axis of rotation 54 may be fixed for a particular engine 10, or the crankshaft 22 may be configured such that the angular orientation of the third axis of rotation 54 may be adjustable within the scope of the present invention.
The third axis of rotation 54 may extend at an angle θ from the line 60 at any angle in a range of between approximately 0 degrees and approximately 90 degrees. In one embodiment, the angle θ may be configured within a range of between approximately 5 degrees and approximately 25 degrees. For example, an angle θ of approximately 15 degrees has been demonstrated to be useful for a particular application. However, it will be appreciated that the third axis of rotation 54 may extend at other angles θ with respect to the line 60 within the scope of the present invention to meet the top dead center and bottom dead center variation needs for a particular use. For example, the top dead center and bottom dead center variation requirements for a particular use may make various angles θ suitable, such as angles θ in ranges of between approximately 0-10 degrees, 10-20 degrees, 20-30 degrees, 30-40 degrees, 40-50 degrees, 50-60 degrees, 60-70 degrees, 70-80 degrees, or 80-90 degrees. For example, the third axis of rotation 54 may extend at an angle θ of approximately 5, 15, 25, 35, 45, 55, 65, 75, or 85 degrees or any other angle depending upon the particular top dead center and bottom dead center variation requirements for a given situation.
Similarly, the journal portion 56 may extend at any angle α from the third axis of rotation in a range of between approximately 0 degrees and approximately 90 degrees. In one embodiment, the angle α may be configured in a range of between approximately 5 degrees and approximately 20 degrees. For example, a crankshaft 22 having a journal portion 56 extending at an angle α of approximately 12 degrees has been demonstrated to exhibit excellent working capabilities for a particular application. However, it will be appreciated that the journal portion 56 may extend at other angles α within the scope of the present invention to meet the required stroke length variation needs for a particular use. For example, the stroke length variation requirements for a particular use may make various angles α suitable, such as angles α in ranges of between approximately 0-10 degrees, 10-20 degrees, 20-30 degrees, 30-40 degrees, 40-50 degrees, 50-60 degrees, 60-70 degrees, 70-80 degrees, or 80-90 degrees. For example, the journal portion 24 may extend at an angle α of approximately 5, 15, 25, 35, 45, 55, 65, 75, or 85 degrees or any other angle depending upon the particular stroke length variation requirements for a given situation. It will also be appreciated that the a curved journal portion 57 may be used within the scope of the present invention, as shown in
The journal portion 56 may have any cross sectional shape, such as round, oblong 56c, triangular 56d, square 56e, rectangular 56f, or I-beam shape 56g, for example, as shown in
A spherical bearing 62 may be supported on the journal portion 56 and received by the connecting rod 20 to allow the journal portion 56 to slide with respect to the connecting rod 20. Accordingly, the spherical bearing 62 may be formed with an opening to receive the journal portion 56. The second end 52 of the angled segment 38 of the crankshaft 22 may have a collar 64 to limit movement of the spherical bearing 62 along the journal portion 56, or to limit movement of the crankshaft 22 with respect to the connecting rod 20. Movement of the spherical bearing 62 along the journal portion 56 may be limited at the first end 50 of the angled segment 38 by the counterweight 66. It will be appreciated that the counterweight 66 and or collar 64 may be positioned on the opposite ends of the angled segment 38 as those described above, or that counterweights 66 or collars 64 may be placed on both ends of the angled segment 38.
The counterweight 66 may be positioned on the crankshaft 22 for balancing the rotational forces of the crankshaft 22 as the crankshaft 22 is rotated. The counterweight 66 may have various shapes known to those skilled in the art, such as a segment of a disk for example. It will be appreciated that the counterweight 66 may be positioned at various locations along the crankshaft 22, including near the first end 50 of the angled segment 38, or near the second end 52 of the angled segment 38. Moreover, multiple counterweights 66 may be positioned on the crankshaft 22, as shown in
The engine 10 may also include a means 70 for moving the crankshaft 22. The means 70 for moving the crankshaft 22 is shown schematically in
As the piston 18 reciprocates, crankshaft 22 may be rotated such that the angled segment 38 rotates about the third axis of rotation 54. The piston 18 reciprocates between a bottom dead center position, or extreme bottom of the piston stroke as shown in
The engine 10 may be configured and arranged such that when the piston 18 in
Accordingly, it will be appreciated that the stroke length of the piston 18 may be adjusted by moving the crankshaft 22 in the direction of arrow 72 with respect to the piston 18 and connecting rod 20 to thereby adjust the radial distance 55. When the crankshaft 22 is moved with respect to the connecting rod 20, the cylinder 14 may act as a guide to hold the piston 18 in place so that the piston 18 does not follow the movement of the crankshaft in the direction 72. Alternatively, it will also be understood that the crankshaft 22 may remain stationary and the engine block 12 containing the piston 18 and connecting rod 20 may be moved with respect to the crankshaft 22.
Accordingly, the stroke length may be adjusted to provide optimal power or efficiency in a continuous manner during operation of the engine 10. The operating conditions of the engine 10 may be monitored by a computerized system as is known in the art and the stroke length may be adjusted accordingly. For example, a longer stroke length may be beneficial for a certain power requirement placed on the engine. This condition may be detected and the stroke length may be automatically adjusted accordingly. Alternatively, the engine 10 may also be configured such that the stroke length may be adjusted manually by the engine operator in accordance with the desired performance characteristics of the operator.
It will be appreciated that the engine 10 also may be configured in certain embodiments to maintain a constant distance between the piston 18 and the engine head 16 when the piston 18 is in a top dead center position at any location along the length of the journal portion 56. For example, the crankshaft 22 may have an angled offset portion 27 as shown in
As is clearly shown in the embodiment of
The first piston 18a and the second piston 18b may be spaced apart along the length of the journal portion 56 such that the first piston 18a and the second piston 18b have different stroke lengths. As can be seen by inspection of
Referring now to
The multiple piston configuration and plurality of journal portions 56a, 56b may enable the engine 10b to be configured for various torque, power, and efficiency conditions. As described above, one or more of the pistons may be turned off. Also, the journal portions 56a, 56b may be configured at different angles such that movement of the crankshaft 22b may adjust the stroke length of each of the pistons 18c-18f differently. It will be appreciated that the present invention may be used with any number of pistons and journal portions within the scope of the present invention.
As is shown in the embodiment of
As shown in
Referring to
It will be understood that the stroke length of the pistons 18 may be modified while the engine 10 is in operation. Similarly, the stroke length of the pistons 18 may be modified while the engine is at rest. Moreover, the stroke length may be continuously variable or variable at multiple set positions within the scope of the present invention.
Referring now to
A first link member 124 may be pivotally attached to the connecting rod 120 at one end and pivotally connected to a second link member 126 at an opposite end. The second link member 126 may be pivotally attached to a counterweight member 128. The counterweight member 128 may have various different configurations within the scope of the present invention, such as a pair of opposing walls 129 spaced apart for receiving the second link member 126 therebetween. The counterweight member 128 may be supported by a brace member 130 and may be configured to rotate about an output member 132. The output member 132 may be a shaft, for example, supported on the brace member 130. It will be appreciated that the output member 132 may have other configurations within the scope of the present invention, such as a gear, disk, or sprocket, for example.
The first link member 124 may also be attached to a sleeve 134. The sleeve 134 may be configured as a hollow member to receive the first link 124 and to slide along the length of the first link member 124. A shaft 136 may be attached to the sleeve 134 and to a slider 138 so that the sleeve 134 may be configured to pivot with respect to the slider 138. It will be appreciated that the sleeve 134, the shaft 136, and the slider 138 may collectively form a fulcrum, indicated generally at 135, for supporting the first link member 124. An enlarged perspective view of the sleeve 134, the shaft 136 and the slider 138 is shown in FIG. 10.
The slider 138 may be attached to the angular support 122 so as to be movable along the length of the angular support 122. In one embodiment, the angular support 122 may have a support slot 140 for receiving the slider 138 and the second link member 126. The second link member 126 may also pass through a base slot 141 disposed in the base 112. The engine 110 may also comprise a means for adjusting the position of the slider 138 along the angular support 122 as shown schematically at 139. It will be appreciated that any means known in the art may be utilized to adjust the position of the slider 138 along the length of the angular support 122. For example, a threaded rod may be attached to the slider 138, such that the threaded rod may be rotated to adjust the position of the slider 138 through a screw type mechanism. Also, a hydraulic ram mechanism may be utilized to adjust the position of the slider 138 along the length of the angular support 122, as well as gears, chains, belts or any other mechanism known in the art for adjusting the position of one member with respect to another.
In operation, downward movement of the piston 118 causes the first link member 124 to pivot about the fulcrum 135 to cause upward movement of the second link member 126 which causes the counterweight member 128 to rotate about the output member 132. As the counterweight 128 continues its revolution around the output 132, the second link member 126 moves downwardly, the first link member pivots about the fulcrum 135 and the connecting rod 120 and piston 118 move upwardly in the cylinder 114.
The output member 132 may rotate to transmit the output through any variety of gear or transmission mechanisms known in the art for use in a variety of applications such as powering wheels of a vehicle for example. However, it will be appreciated that the output of the engine 110 may be available for any use known in the art.
It will be understood that the stroke length of the piston 118 may be adjusted by moving the slider 138 along the length of the angular support 122. As shown in
As shown in the perspective view of
It will be appreciated that the principles of the present invention, in all embodiments, may be used with engines having various different configurations and using various different numbers of cylinders. For example, as shown in
Referring now to
It will be appreciated that the structure and apparatus disclosed herein is merely one example of a means for moving the crankshaft, and it should be appreciated that any structure, apparatus or system for moving the crankshaft which performs functions the same as, or equivalent to, those disclosed herein are intended to fall within the scope of a means for moving the crankshaft, including those structures, apparatus or systems for moving the crankshaft which are presently known, or which may become available in the future. Anything which functions the same as, or equivalently to, a means for moving the crankshaft falls within the scope of this element.
It will be appreciated that the structure and apparatus disclosed herein is merely one example of a means for adjusting the position of the slider along the angular support, and it should be appreciated that any structure, apparatus or system for adjusting the position of the slider which performs functions the same as, or equivalent to, those disclosed herein are intended to fall within the scope of a means for adjusting the position of the slider, including those structures, apparatus or systems for adjusting the position of the slider which are presently known, or which may become available in the future. Anything which functions the same as, or equivalently to, a means for adjusting the position of the slider falls within the scope of this element.
In accordance with the features and combinations described above, a useful method of adjusting the stroke length of a piston in an internal combustion engine includes the steps of:
(a) extending a journal portion of a crankshaft along a non-perpendicular angle with respect to an axis of movement of the piston; and
(b) moving the crankshaft in a longitudinal direction with respect to the piston.
Those having ordinary skill in the relevant art will appreciate the advantages provide by the features of the present invention. For example, it is a feature of the present invention to provide an internal combustion engine that is simple in design and manufacture. Another feature of the present invention is to provide such an engine that has an adjustable stroke length to enhance working efficiency, power and torque capabilities of the engine. It is a further feature of the present invention, in accordance with one aspect thereof, to provide a stroke adjustment mechanism that can be used with engines having different strokes and using different varieties of fuel such as gasoline, kerosene, diesel, propane, oil, or natural gas. Moreover, the adjustable stroke length characteristic of the present invention allows the engine to operate at optimal efficiency, power, and torque under various conditions of temperature, atmospheric pressure or load conditions.
It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been shown in the drawings and described above with particularity and detail, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.
This application claims the benefit of a U.S. Provisional Application No. 60/425,110, filed Nov. 7, 2002, entitled “VARIABLE DISPLACEMENT ENGINE” which is hereby incorporated by reference herein in its entirety, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portion of the above-referenced provisional application is inconsistent with this application, this application supercedes said above-referenced provisional application.
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Number | Date | Country | |
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20040089252 A1 | May 2004 | US |
Number | Date | Country | |
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60425110 | Nov 2002 | US |