An ongoing challenge is to improve the combustion efficiency of opposed-piston engines, thereby enhancing the performance of four-stroke opposed-piston engines. In particular, with certain piston faces, some combustion residue may accumulate if the combustion mixture is not optimally combusted. It is believed that optimum performance of the engine may be affected because of uneven combustion burn, for example.
Another challenge is to reduce the size and complexity of the engine. If certain efficiencies can be built into the incorporation of different parts such as the gear train connected to the crank(s) in the engine, then certain parts may be removed and the size and weight of the overall engine may be reduced.
These and other concerns are addressed by the structural advantages as discussed below.
A four-stroke opposed piston engine contains: a first cylinder containing a first piston and a second piston opposing the first piston; a second cylinder containing a third piston and a fourth piston opposing the third piston; a first piston face contained on the first piston, and, a second piston face contained on the second piston, the first and second pistons each containing respective first annular regions, wherein the first annular regions define a first combustion chamber when the first and second pistons are at top dead center. A third piston face is contained on the third piston, and, a fourth piston face is contained on the fourth piston, the third and fourth pistons each containing respective second annular regions, the second annular regions defining a second combustion chamber when the third and fourth pistons are at top dead center; a first crank shaft operably communicating with the first and third pistons; and a second crank shaft operably communicating with the second and fourth pistons.
In yet another aspect of the present invention, a four-stroke opposed piston engine contains: a first cylinder containing a first piston and a second piston opposing the first piston; a second cylinder containing a third piston and a fourth piston opposing the third piston; a first crank shaft operably communicating with the first and third pistons; a second crank shaft operably communicating with the second and fourth pistons; and a drive train containing a first crank shaft gear connected to the first crank shaft, a second crank shaft gear connected to the second crank shaft gear, a first synchro gear rotatably communicating with the first crank shaft gear, and a second synchro gear rotatably communicating with the second crank shaft gear and the first synchro gear. Importantly, the first and second crank shaft gears are equal in diameter and the first and second synchro gears equal in diameter and twice the diameter of the first and second crank shaft gears.
Stated another way, the four-stroke opposed piston engine contains: a first cylinder containing a first piston, and, a second piston opposing the first piston; a second cylinder containing a third piston, and, a fourth piston opposing the third piston; a first crank shaft operably communicating with the first and third pistons; a second crank shaft operably communicating with the second and fourth pistons; and a drive train containing a first driver operably communicating with the first crank shaft, a second driver operably communicating with the second crank shaft, a third driver operably communicating with the first driver, and, a fourth driver communicating with the second driver, wherein the third and fourth drivers each have a diameter twice that of the first and second drivers. As stated above, the drivers may correspond to the four-gear driver described above and elsewhere in this application. Furthermore, the drivers may, for example only, constitute a belt-driven pulley system wherein each of the four drivers characterized above constitutes a pulley-driven system. In each of the embodiments, the drivers function and operably communicate with respective valve assemblies as described herein, without the need for reducing apparatus.
The novel aspects of the present invention are presented below. U.S. Pat. Nos. 7,004,120 and 7,779,795, and U.S. patent application Ser. No. 13/633,097 are related to the present invention, the teachings of which are herein incorporated by reference in their entireties.
Referring to
Referring to
In one embodiment, the stroke length of each of pistons 520 and 530 is about 3 inches. Thus, the total difference between the spacing of the pistons at closest approach to each other (i.e., at “top dead center”) may range from 0 inches to 0.25 inches, and more preferably from about 0.05 inches to 0.2 inches, and the maximum spacing of the pistons during the engine cycle (i.e., at “bottom dead center”) is about 4-7 inches, and more preferably about 6 inches. As will be apparent to one of ordinary skill in the art, these distances may be altered depending on specific design criteria.
If desired, the piston lengths may be adjusted (to substantially equal lengths) for controlling spacing between the piston faces, thereby providing a means for adjusting the compression ratio and generally providing a predetermined degree of compression for heating intake air to facilitate combustion of a fuel injected or otherwise inserted into the combustion chamber. The piston lengths are geometrically determined in accordance with the piston stroke length and the lengths of apertures (described below) formed in the cylinders through which flow exhaust gases and air for combustion. In one embodiment, each piston cap 524 and 534 is formed from a sandwich of two sheets of carbon fiber with a ceramic center.
In accordance with the present invention, the piston caps 524 and 534 which are exposed to the combustion event are formed so that when the two piston caps 524 and 534 meet in the center of the cylinder 510 they preferably form a somewhat toroidal, hour-glass-shaped, or otherwise-shaped cavity as the combustion chamber 521, as shown in
Each piston should have a length from the piston fire ring to the cap suitable for keeping the piston rings out of the cylinder opening(s) 510a. The piston caps 524 and 534 each have a diameter roughly equal to the interior of the associated cylinder, and may be made of carbon fiber, ceramic, and/or any other suitable material to aid in minimizing thermal inefficiencies during engine operation.
In an embodiment utilizing a delivery conductor and ground conductor for spark generation (as described in U.S. Pat. No. 7,448,352, herein incorporated by reference in its entirety), the face of each piston may also include a slot(s) or groove(s) (not shown) formed therein and configured for providing a clearance between the piston face and the delivery and ground conductors, as the pistons approach each other within the cylinder.
Alternatively, and as shown in
Accordingly, referring to
In further accordance with the present invention, and in one embodiment of the present invention, the drive mechanism or gear train 512 converts rotational motion of the crank shafts to rotational motion of a first and second pair of cam discs 550, 550′, 552, and 552′. Accordingly, the first pair of cam discs 550 and 550′ are each rotationally and coaxially fixed and mounted to the exterior of the third gear 512c, such that the gear 512c and the associated pair of cam discs 550 and 552 all rotate at the same speed. In one embodiment, these cam discs 550 and 552 operate the inlet valves for each cylinder. In the same way, the second pair of cam discs 550′ and 552′ are each rotationally and coaxially fixed and mounted to the exterior of the fourth gear 512d, such that the gear 512d and the associated cam discs 550′ and 552′ all rotate at the same speed. In the same embodiment, these cam discs 550′ and 552′ operate the exhaust valves for each cylinder.
Various elements of the vehicle and/or engine systems (for example, an oil pump or coolant circulation pump) may be operatively coupled to and powered by the gear train 512, via the gears in the gear train 512 or via shafts and additional gears operatively coupled to the gear train 512 (not shown).
Referring again to
Referring to
The valve assemblies 560, 562, 564, 566 of the present invention may be any known or applicable valve assembly. A preferred valve assembly is formed in a known manner as a Desmodromic valve assembly. As known in the art, a Desmodromic valve is a reciprocating engine valve that is positively closed by a cam and leverage system, rather than by a more conventional spring. Each Desmodromic valve assembly contains a plurality of connected armatures for actuation of an associated valve responsive to the cam groove of the cam disc. The width and the depth of the cam groove 554 may be tailored to affect the desired timing of the respective valve actuation. Alternatively, the cam disc 550-552′ might itself be spooled inwardly toward the gear drive 512 or outwardly away from the gear drive 512 by known drivers, thereby obviating the need to vary the depth of the cam groove 554 to accomplish the same function. A first armature 537 of the valve assembly contains a cam follower 539 that traces the cam groove 554 as the cam disc 550-552′ rotates responsive to the associated gear 512c or 512d. In general, the mechanism by which a camming surface engages a follower arm to actuate a rocker arm so as to open and close an associated poppet valve is known in the art, and the similar operation of the particular valve embodiments shown in the FIGURES to control flow into and out of the cylinder combustion chamber 521 are described herein. Referring to
A conventional poppet valve 525/527, has a conventional valve stem 525a/527a having a plug 525b/527b mounted to a first end 525c/527c of the stem, whereby the first end of the stem is fixed to the rocker arm or valve actuator 547. A valve seat 525d/527d is contained in the cylinder opening 510a/510b and functions as a valve guide and seat during operation of the four-stroke cycle. As indicated in the FIGURES, the valve 525/527 opens and closes as it vertically moves within the valve guide or valve seat 525d/527d. A corresponding detent or depression 520a/530a, collectively formed in the geometry of the dual-piston 520/530 interface at top dead center, provides a clearance for operation of the valve within the cylinder.
The base and projecting portions 517, 519 of the cam 550-552′ are positioned and secured with respect to each other so as to form a continuous camming surface or profile 556 engageable by an associated actuatable valve element (such as a cam follower 539 as described above) as the cam disc 550-552′ rotates. Thus, the actuatable valve element or cam follower 539 will alternately engage the cam base portion(s) 517 and any projecting portion(s) 519 as the cam 550-552′ rotates.
In the embodiment shown in
Referring to
In other embodiments, any one of multiple intermediate states of the valve assembly may be achieved and maintained by providing cam projecting portions defining cam surfaces located at corresponding distances from the rotational axis A of the cam disc 550. All cam discs 550-552′ essentially operate in the same manner. For example, in one embodiment, beginning at a point in the base projection, the intake valve 525 is opened as the exemplary cam disc 550 rotates 180 degrees from the beginning point, and the cam follower 539 cycle through greater radial distances as the disc 550 rotates through the projecting portions 519 of the disc, thereby defining the intake cycle of the four-stroke process. As the cam disc 550 continues to rotate, the intake valve 525 is closed as the cam disc 550 again approaches the base portions 517, and the compression cycle is conducted from about 181 degrees to 360 degrees of the rotation through the base portions 517 of the cam disc 550. As the cam disc 550 continues to rotate another 180 degrees for a total of 540 degrees, the expansion or combustion cycle is conducted, whereby both of the intake and exhaust valves 525, 527 are closed to seal the combustion chamber 521 during the expansion cycle. Finally, as the cam disc 550 rotates another 180 degrees for a total of 720 degrees of rotation, the exhaust cycle is completed whereby all exhaust gases exit the cylinder as they are shunted through the exhaust valve 527. Once the exhaust cycle is complete, the cam disc 550 then repeats the process to again rotate 720 degrees as the four-stroke process is repeated during the engine operation. In the embodiment shown in
In a particular embodiment, when the actuatable portion or cam follower 539 of the valve assembly 560, 562, 564, or 566 engages and slides along the base portion(s) 517 of the cam profile 556, the associated valve assembly is in a closed condition (i.e., the valve assembly prevents flow of air into (or exhaust gases from) the cylinder combustion chamber 521. Also, when the cam follower or actuatable portion 539 of the valve assembly engages and slides along the projecting portion(s) 519, the valve assembly is in an open or partially open condition (i.e., the valve assembly permits flow of air into (or exhaust gases from) the cylinder combustion chamber 521.
The camming discs or elements 550-552′ may be in the form of rings or other structures attachable to the exterior surface of the gears 512c and 512d. In a particular embodiment, the base and projecting portions 517 and 519, respectively, of the camming elements or discs 550, 550′, 552, or 552′, are modular in construction so that these elements may be changed out to provide any of a variety of cam profiles. In addition, the projecting portions of a cam profile may be changed out independently of the base portions of the profile. These options enable greater flexibility in control of the valve sequencing, enabling correspondingly greater control of the engine cycle.
Base portion(s) 517 and projecting portion(s) 519 may be attached to the cam disc 550 (or any other of the cam discs) using any suitable method, thereby creating a first arcuate region defined by the base portions 517 and a second arcuate region that is defined by ramped radial lengths of the projecting portions 519 as shown in
Because the projecting portion 519 actuating the valve 525 can be relocated so as to engage the valve 525 either sooner or later during rotation of the cam disc 550 (and, therefore, sooner or later in the engine cycle), the associated valve 525 may be opened or closed either sooner or later during the engine cycle. Thus, in one embodiment, the detachability and modularity of the camming elements 517 and 519 of the cam disc 550 may enable fine tuning of the engine cycle by adjustment of the valve actuation timing.
Alternatively, the cam discs 550, 550′, 552, 552′ may be formed as a machined monolithic disc wherein the respective cam groove 554 defined by the base portions 517 and projecting portions 519 may be altered by changing the entire cam disc 550 for one that has been machined to change the variability of the radial distances of the projecting portions 519, and perhaps the arcuate length of the base portions 517 and the projecting portions 519. The change in the design of the cam groove 554 therefore facilitates actuation of the valve 525 (or the valve 527) at a different point in the engine cycle and/or for a different length of time.
A follower 539 operatively connected to an associated valve 525 and valve 527 engages and follows the camming surfaces 556 of the disc 550 as the disc rotates. When the follower 539 reaches and engages a plurality of the ramped camming surface 519a residing in the projecting portions 519 of the cam disc 550 (as shown in
Referring to
A first crank shaft 540 is coaxially fixed to the first gear 512a, through medial portion 512a′ of the first gear 512a. A first rod 522 is also coaxially fixed about a first end of the first crank shaft 540, and fixed to a first piston 520, for cycling the first piston 520 within a first cylinder 510. A second rod 522′ is fixed about a second end of the first crank shaft 540, and fixed to a second piston 522′, for cycling the second piston 522′ within a second cylinder 510′. A third gear 512c is rotatably engaged with the first drive gear 512a. A first cam disc 550 and a second cam disc 550′ are rotatably, coaxially, and concentrically oriented with, or fixed to, the third gear 512c, each cam disc about an opposite side of the gear 512c.
As schematically shown in
A second valve assembly 562 is fixed above the engine and is operatively connected to the cam disc 550′, for opening and closing of a second inlet valve 525′ (not shown) also operatively connected to the second valve assembly 562. A second valve seat 525a′ (not shown) functions as a guide and a seat for the second inlet valve 525′ as the plurality of arms 537, 539, 541, and 543 of the second valve assembly 530 respond to the cam follower 539, as described above, to thereby actuate the second inlet valve 525′ in conjunction with the cam profile 556 of the cam disc 550′.
A second crank shaft 542 is coaxially fixed to the second gear 512b, through medial portion 512b′ of the second gear 512b. A third rod 532 is also coaxially fixed about a first end of the second crank shaft 542, and fixed to a first piston 530, for cycling the first piston 530 within a first cylinder 510. A fourth rod 532′ is fixed about a second end of the second crank shaft 542, and fixed to a fourth piston 530′, for cycling the fourth piston 530′ within the second cylinder 510′. A fourth gear or synchro gear 512d is rotatably engaged with the first drive gear 512b and the third drive gear 512c. A third cam disc 552 and a fourth cam disc 552′ are rotatably, coaxially, and concentrically oriented with, or fixed to, the fourth gear 512d, each cam disc fixed to an opposite side of the gear 512d. See
A third valve assembly 564 is positioned beneath the engine 500 and operatively connected to the cam disc 552, for opening and closing of a first exhaust valve 527 also operatively connected to the third valve assembly 564. A third valve seat 525c (not shown) functions as a guide and a seat for the first exhaust valve 527 as the plurality of arms 537, 539, 541, and 543 of the third valve assembly 564 respond to the cam follower 539, as described above, to thereby actuate the first exhaust valve 527a in conjunction with the cam profile 556 of the cam disc 552.
A fourth valve assembly 566 is operatively connected to the cam disc 552′, for opening and closing of a second exhaust valve 527′ also operatively connected to the fourth valve assembly 534. A fourth valve seat 527a′ (not shown) functions as a guide and a seat for the second exhaust valve 527′ as the plurality of arms 537, 539, 541, and 543 of the fourth valve assembly 566 respond to the cam follower 539, as described above, to thereby actuate the second exhaust valve 527′ in conjunction with the cam profile 556 of the cam disc 550′.
As shown in
Other housing components of the engine 500 are illustrated in
In accordance with the present invention,
It will be understood that the foregoing descriptions of various embodiments of the present invention is for illustrative purposes only. As such, the various structural and operational features herein disclosed are susceptible to a number of modifications, none of which departs from the scope of the present invention as defined in the appended claims.
The present application claims the benefit of U.S. Provisional Application Ser. No. 62/299,154 having a filing date of Feb. 24, 2016, the teachings of which are herein incorporated by reference in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
1431188 | Sinclair | Oct 1922 | A |
1511338 | Holderness | Oct 1924 | A |
1644954 | Shearer | Oct 1927 | A |
1837870 | Johnston | Dec 1931 | A |
1889946 | Cadwell | Dec 1932 | A |
1958957 | Rakos | May 1934 | A |
2495978 | Maxwell | Jan 1950 | A |
2699156 | Karow | Jan 1955 | A |
2858816 | Prentice | Nov 1958 | A |
4037572 | Franz | Jul 1977 | A |
4164915 | Kulhavy | Aug 1979 | A |
4244338 | Rassey | Jan 1981 | A |
4375792 | Barret | Mar 1983 | A |
5042441 | Paul | Aug 1991 | A |
5133306 | Honkanen | Jul 1992 | A |
5758610 | Park | Jun 1998 | A |
7559298 | Cleeves | Jul 2009 | B2 |
8413619 | Cleeves | Apr 2013 | B2 |
8677950 | Hofbauer | Mar 2014 | B2 |
8776739 | Cleeves | Jul 2014 | B2 |
8789499 | Alonso | Jul 2014 | B2 |
9211797 | Abani | Dec 2015 | B2 |
9309807 | Burton | Apr 2016 | B2 |
9482145 | Hofbauer | Nov 2016 | B2 |
9708976 | Warren | Jul 2017 | B1 |
10161371 | Johnson | Dec 2018 | B2 |
10662893 | Powell | May 2020 | B1 |
20040221823 | Warren | Nov 2004 | A1 |
20070028866 | Lindsay | Feb 2007 | A1 |
20070095309 | Reisser | May 2007 | A1 |
20080047530 | Cleeves | Feb 2008 | A1 |
20080115771 | Elsbett | May 2008 | A1 |
20100147269 | Flowers | Jun 2010 | A1 |
20100218744 | Simon | Sep 2010 | A1 |
20110094470 | Augot | Apr 2011 | A1 |
20110162621 | Xu | Jul 2011 | A1 |
20110271932 | Fuqua | Nov 2011 | A1 |
20120031379 | Zhou | Feb 2012 | A1 |
20120055451 | Jorda | Mar 2012 | A1 |
20120073541 | Fuqua | Mar 2012 | A1 |
20120085305 | Cleeves | Apr 2012 | A1 |
20130036903 | Daniels | Feb 2013 | A1 |
20160175874 | Beck | Jun 2016 | A1 |
20160237945 | Jeffries | Aug 2016 | A1 |
20170030262 | Venugopal | Feb 2017 | A1 |
20170122199 | Andersson | May 2017 | A1 |
20170254261 | Morton | Sep 2017 | A1 |
20170335752 | Morton | Nov 2017 | A1 |
Number | Date | Country |
---|---|---|
202012005573 | Aug 2012 | DE |
750231 | Aug 1933 | FR |
565276 | Nov 1944 | GB |
Entry |
---|
FR 750231 Translation (Year: 1933). |
Number | Date | Country | |
---|---|---|---|
62299154 | Feb 2016 | US |