Field of Invention
The invention relates to a combination of spark ignited and compression ignited two cycle engines.
Background of Invention
Generally, internal combustion engines are divided into two classes: spark ignited and compression ignited. Both internal combustion engine types have their advantages and disadvantages. Spark ignited engines have lower compression ratios, weigh less and are easier to start as they initiate fuel burn after top dead center. However, spark ignited engines are less efficient as they release burning fuel out the exhaust. Compression ignited engines, known as diesel engines, have much higher compression ratios and therefore require more energy to start. Compression engines are more efficient, as the fuel is fully combusted inside the cylinder but detonated before top dead center. Typically, spark ignited engines efficiency is in the low 40% range, whereas diesel type engines typically have an efficiency in the mid-40% range, even though they lose energy by detonating before top dead center.
Therefore, there is a need in the industry to combine many of the best aspects of both types of engines.
The present invention is directed to a low friction two cylinder, two cycle opposed-piston internal combustion engine. In an aspect, the two cylinder, two cycle opposed-piston internal combustion engine utilizes two combustion cylinders with a Scotch yoke assembly. In an aspect, the Scotch yoke assembly includes two combustion pistons connected together through a Scotch yoke base. The combustion pistons are configured to operate within the combustion cylinders.
In an aspect, the two cylinder, two cycle opposed-piston internal combustion engine can include a pair of compression cylinders. In such aspects, the Scotch yoke assembly can include two compression pistons configured to operate within the compression cylinders. In an aspect, the two opposed compression pistons can be configured to be driven by the Scotch yoke base to function as an air compressor.
In an aspect, the Scotch yoke base keeps both sets of pistons in accurate concentricity to their respective cylinder walls, enabling close tolerances without actual contact between the pistons and their respective cylinder walls. In an aspect, the Scotch yoke assembly includes a Scotch yoke guide shaft configured to guide the movement of the Scotch yoke base and connected pistons. In an aspect, the combination of the Scotch yoke base and the opposed combustion pistons, compression pistons, and the Scotch yoke guide shaft also enables the establishment of a near frictionless inviscid layer seal allowing the compression and combustion pistons to compress on both sides of the heads of the pistons without the use of piston rings.
In an aspect, some compressed air is used to purge the exhaust gases out of the combustion cylinder, which is released from the backside of the combustion piston. The remaining air can be used in the combustion cycle. In an aspect, the two cylinder, two cycle opposed-piston engine is configured so that the combustion air is introduced at the bottom of the stroke, and as it is being compressed, fuel is injected at multiple points during the compression stroke to facilitate mixing.
In an aspect, the two cylinder, two cycle opposed-piston engine is configured to initially start with a spark plug. As the engine warms up, some of the combustion gases are captured by a detonator accumulator system. In an aspect, the detonator accumulator system can utilize detonation valves and a detonation accumulator chamber to capture combustion gases from one combustion cylinder and to release the collected combustion gases into the opposing combustion cylinder to initiate fuel detonation. In an aspect, the detonation valve to the detonation accumulator chamber opens in time to detonate the fuel within the combustion cylinder and remains open long enough to recharge the detonation accumulator chamber with fresh high-temperature high-pressure gases to be used to detonate the opposing combustion cylinder. In an aspect, detonation occurs at top dead center or slightly after top dead center.
In an aspect, the two cylinder, two cycle opposed-piston engine can utilize two flywheels inside of a crankcase area on either side of the Scotch yoke. In an aspect, the flywheels can be configured to provide an inviscid layer for lubrication of components of the two cylinder, two cycle opposed-piston engine. In an aspect, the two cylinder, two cycle opposed piston engine can be configured to isolate the two flywheels within the crankcase.
In an aspect, the use of the Scotch yoke assembly and inviscid layer sealing eliminates the need for cylinder lubrication. Therefore all major lubrication takes place in a sealed crankcase. The crankcase may be configured to be in close proximity to the two flywheels, and sufficient lubricant is installed to allow portions of the flywheels to interface with the lubricant no matter the angle of the engine. In an aspect, parasitic drag between the flywheels and the lubricant causes the lubricant to vaporize. In an aspect, the vaporized lubricant is collected into a pickup and return tube system through parasitic drag and then transmitted to an exhaust valve assembly. Likewise, parasitic drag is used to create a low pressure path to return the excess vaporized lubricant back to the crankcase.
In an aspect, one flywheel actuates both exhaust valves and the other actuates both accumulator detonation valves. In another aspect, one flywheel can operate the opening of the exhaust valves and the other flywheel can operate the closing of the exhaust valves. In another aspect, one of the flywheels can be configured to control some operation of the exhaust valves and accumulator detonation valves. In an aspect, the two flywheels can include valve cams to actuate the exhaust valves and accumulator detonation valves.
In an aspect, mechanical power is transmitted from the combustion pistons through the respective connecting rods through the Scotch yoke base to the crankshaft through a multi-rotational element bearing. That power is transmitted to the output shafts located on both sides of the engine. In an aspect, the output shafts can include a male spline on one end of the crankshaft and a female spline on the other end of the crankshaft. In this way multiple engines can be cascaded for added power.
In an aspect, the two cylinder, two cycle opposed-piston engine can be configured to generate electricity. In an aspect, the cylinder walls of the two cylinder, two cycle opposed-piston engine can be lined with ceramic material. Inside of the ceramic lining, copper coils can be embedded and the pistons can be fitted with high-strength magnets since the combustion pistons never actually contact the walls of the combustion cylinders. As the pistons go back and forth through the coils, the magnetic lines of force are cut and an electric current is generated in the windings. That current is transmitted to a power conditioning module which conditions the power appropriately.
These and other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute part of this specification, illustrate several embodiments of the invention, and together with the description serve to explain the principles of the invention.
Before the present methods and systems are disclosed and described, it is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or to particular compositions. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to an “outer-inner race”, or “bearing element” can include two or more such elements unless the context indicates otherwise.
Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes.
Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods.
References will now be made in detail to the present preferred aspects of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible the same reference numbers are used throughout the drawings to refer to the same or like parts.
As illustrated in
In an aspect, the two engine segments 101, 102 share certain common components. In an exemplary aspect, the two engines 101, 102 of the opposed-piston engine 100 share an engine case 104. The engine case 104 can form a crankcase 105, discussed in more detail below. The two engine segments 101, 102 can also share a Scotch yoke assembly 200 Scotch, a crankshaft assembly 300, an exhaust cam flywheel 330, a detonator cam flywheel 335, main bearings 360, a control module (not shown for clarity) and the crankshaft angle sensor (not shown for clarity), amongst others discussed in more detail below.
The Scotch yoke assembly 200 is configured to control the functions of the opposed-piston engine 100. In an aspect, as illustrated in
The Scotch yoke base 205 is configured to oscillate within the crankcase 105 during the operation of the opposed-piston engine 100. The Scotch yoke guide shaft 207 supports the linear motion of the Scotch yoke base 205 within the crankcase 105. In an aspect, the Scotch yoke guide shaft 207 is rigidly connected to the engine case 104, and the shaft 207 is received by a linear bearing 209 oriented within the Scotch yoke base 205, as shown in
Referring back to
In an aspect, the two compression cylinders 110 are configured to allow the compression pistons 210 to travel within them. The compression pistons 210 are configured to compress air within the compression cylinders 110 in order to provide charged air to the combustion cylinders 130. The compression pistons 210 are connected to one another through a compression connecting rod 211, which is then secured to the Scotch yoke base 205. In another aspect, the compression pistons 210 can be connected to the Scotch yoke base 205 with individual connecting rods.
In an aspect, the compression connecting rod 211 is configured to extend through apertures (not shown) in the engine case 104 that extend from the compression cylinders 110 into the crankcase 105. Compressor linear bearings and seals 119 engage the connecting rod 211 within the apertures and allow the connecting rod 211 to travel within the compression cylinders 110 while isolating the crankcase 105 from the compression cylinders 110, keeping air from escaping from the compression cylinders 110 into the crankcase 105, as shown in
The movement of the compression pistons 210, connected by the compression connecting rod 211, is controlled by the Scotch yoke base 205, with the connecting rod 211 and the compression pistons 210 moving in connection with the Scotch yoke base 205. With the compression pistons 210 connected to the same compression connecting rod 211 and connected to the Scotch yoke base 205 (or when two separate connecting rods 211 are connected to the Scotch yoke base 205), the compression pistons 210 in opposite compression cylinders 110 move in concert with one another. More specifically, when the compression piston 210 on side A of the opposed-piston engine 100 (i.e., the first segment 101) is located at the end of the compression cylinder 110 furthest away from the crankcase 105, the compression piston 210 on side B (i.e., second segment 102) will be located closer to the crankcase 105, and vice versa. In an aspect, the compression pistons 210 are configured to travel within the compression cylinders 110 without engaging the walls of the compression cylinders 110. In such aspects, the compression cylinders 110 do not need piston rings or lubrication beyond the inviscid layer, as discussed above and further 1 below.
The compression cylinders 110 are further configured to include at least one one-way intake valve assembly 115, shown in
The one-way intake valve assemblies 115 are configured to allow ambient air into the compression cylinders 110. In an aspect, when the air pressure of the ambient air is greater than the air pressure within the compression cylinders 110, the ambient air, applying pressure on the surface of the valve face 116, compresses the spring 117, allowing air into the compression cylinders 110, as shown in
Adjacent the compression cylinders 110 are the accumulator chambers 120, as shown in
The check valve assemblies 125 are configured to allow air from the compression cylinders 110 into the accumulator chambers 120. In an aspect, when the air pressure of the air within the compression cylinders 110 is greater than the air pressure within the accumulator chambers 120, the air within the compression cylinders 110 apply pressure on the surface of the valve face 126, compressing the spring 127, allowing air into the accumulator chambers 120, as shown in
In an aspect, the opposed-piston engine 100 includes combustion cylinders 130. The combustion cylinders 130 are adjacent the air accumulator chambers 120 on the side opposite the compression cylinders 110, as shown in
In an aspect, an electrode-end of at least one spark plug 131 is configured to reside within the combustion cylinders 130, as shown in
The combustion cylinder 130 includes an intake port 137 configured to provide a passage way for the charged air to enter into the combustion cylinder 130 from the accumulator chamber 120. In an aspect, the combustion cylinder 130 can include a purge port 138 can be found opposite the intake port 137. The purge port 138 is configured to purge exhaust and unused fuel from the combustion chamber when an exhaust valve 511 is opened, discussed in detail below.
The combustion pistons 230 are configured to move within the combustion cylinders 130. In an aspect, the combustion pistons 230 are configured to travel back and forth through the combustion cylinders 130 without coming in contact with the walls of the combustion cylinders 130, thereby eliminating the need for piston rings on the pistons 230, greatly reducing the friction and thereby the need of lubricants within the combustion cylinders 130. The head 230a of the combustion pistons 230 are connected to the Scotch yoke base 205 through piston connecting rods 231. The piston connecting rods 231 are connected to the Scotch yoke base 205 with retainer fasteners 232. By connecting the combustion pistons to a Scotch yoke base 205 and limiting the motion of the pistons 230 and connecting rods 231 to a linear fashion, the pistons 230 do not need to be able to pivot from the connecting rods 231, and therefore do not need wrist pins or rotating connecting rods, which are replaced by the rigid connecting rods 231. By eliminating the need of wrist pins, the pistons 230 are not able to rock back and forth within the cylinders 130, thereby avoiding making contact with the cylinder walls, which would destroy the invicsid layer and seal. In addition, wrist pins also add weight and eat energy, thereby reducing the overall efficiency of an engine.
The combustion pistons 230 in combination with the combustion cylinders 130 can be used for combustion purposes, as well as purging purposes. In an aspect, the heads 230a of the combustion pistons 230 movably bisect their respective combustion cylinders 130 into two segments: a combustion segment 130C and a purge segment 130P. The combustion segment 130C is found on the face-side 234 of the head 230a of the combustion piston 230, with the purge segment 130P found on the connecting rod side of the head 230a. As the combustion pistons 230 move within the combustion cylinders 130, the length and volume of the combustion segment 130C and the purge segment 130P changes. The combustion segment 130C grows as the combustion piston 230 moves towards the crankcase 105 as the purge segment 130P decreases, and vice versa.
The Scotch yoke base 205 includes a slotted raceway 206 that provides a slot for which a bearing assembly 350 can transmit combustion forces from the combustion pistons 230 to a crankshaft assembly 300, discussed in detail below. Since the combustion pistons 230 are dissected by the Scotch yoke base 205, a piston connecting rod 231 is required for each side (A, B) of the opposed-piston engine 100. In an aspect, the faces 234 of the combustion piston heads 230a include a purge recess 236 and an intake lip 237, as shown in
In an aspect, as shown in
The crankshaft assembly 300 can be mated to the engine case 104 through two main bearings 360, as shown in
In an aspect, the ends of the crankshaft assembly 300 include flywheels 330, 335. Like most of the components of the crankshaft assembly 300, the flywheels 330, 335 are contained within the crankcase 105. In an aspect, the end of the detonator main journal 301 opposite the rod journal 303 is configured to receive a detonator flywheel 335, as shown in FIG. 8. In an aspect, the detonator flywheel 335 is configured to include a cam 335a, shown in
In an aspect, the flywheels 335, 330 can be configured to pump lubrication to remote areas of the engine 100, described in detail below. In an aspect, the flywheels 330, 335 include lubrication pickup tubes 601 that are connected to pickup hoses 602. Likewise, the flywheels 335, 330 can include lubrication return tubes 603 connected to return hoses 604 aligned with a lubrication return hose 604, discussed in detail below. In an aspect, the crankshaft assembly 300 can also include means for transmitting rotational forces. In an exemplary aspect, the outside ends of the crankshaft assembly 300 can include a male spine 355 and a female spine 356, as shown in
As shown in
In an aspect, the bearing assembly 350 comprises three races: an inner race 351, a middle race 353, and an outer race 355, as shown in
As discussed above, the detonator flywheel 335 is configured to operate with a detonator accumulator system 400, shown in
As illustrated in
The chamber end 421b of the push rod 421 is configured to receive a return spring 427. In an aspect, the return spring 427 is coupled to the engine case 104, as shown in
As discussed above, the exhaust flywheel 330 is configured to operate with an exhaust system 500, shown in
As shown in
The valve spring assembly 510 is configured to be controlled by the rocker arm assembly 520 and push rod assembly 530. In an aspect, the rocker arm assembly 520 is configured to engage the push rod assembly 530. The rocker arm assembly 520 includes a rocker arm 521. The rocker arm 521 includes a valve end 521a and a rod end 521b. The middle of the rocker arm 521 includes a bearing 522 configured to engage a pivot point (not shown for clarity purposes) within the valve cover 519. In an aspect, the rod end 521b of the rocker arm 521 includes an adjustment aperture 523 that is configured to receive an adjustment pivot 524, as shown in
The push rod assembly 530 is configured to interact with the exhaust flywheel 330 and the rocker arm assembly 520, as shown in
The push rod 531 includes a cam end 531a and a pivot end 531b. The cam end 531a of the push rod 531 is configured to engage the cam 330a of the exhaust flywheel 330. In an aspect, the cam end 531a of the push rod 531 is configured to receive a cam follower 532. The cam end 531a of the push rod 531 can be configured to have a slot 533 to receive the cam follower 532. The cam follower 532 can include a bearing 534 that corresponds in size to apertures 535 on the cam end 531a, all of which are configured to receive a retention pin 536 to retain the cam follower 532 within the slot 533. The cam follower 532 is configured to engage the cam 330a of the exhaust flywheel 330 as the flywheel 330 rotates. The pivot end 531b of the push rod 531 is configured to engage the end 524a of the adjustment pivot 524. In an exemplary aspect, the pivot end 531b can include an indention 537 that corresponds with the shape of the rod end 524a of the pivot 524.
As shown in
When the cam 330a of the exhaust flywheel 330 engages the cam end 531b, and more specifically the cam follower 532, of the push rod 531, the pivot end 531b of the rod 531 pushes the adjustment pivot 524, which engages the stem 513 of the valve 511 while compressing the spring 514, forcing the exhaust valve 511 to open within the exhaust port 136, allowing exhaust to exit the combustion cylinder 130 through the exhaust port 136.
As shown in
In an aspect, the exhaust manifold 540 can include noise cancelling exhaust elements which include, but are not limited to, a tuning chamber 550, a tuning actuator 552, exhaust sensors 554, and an active tuning element 556. The combination of these elements work together to reduce the overall noise produced by the exhaust. For example, the tuning chamber 550 can be of a size that is big enough to absorb the exhaust pressure wave from one engine segment 101 of the opposed-piston engine 100 and slow the velocity of the exhaust pressure wave in time to allow an exhaust pressure wave from the other engine segment 102 to arrive and reduce the velocity of the second wave as well, allowing the waves to then make the turn to exit, thus absorbing the sound energy. In addition, since components of the opposed-piston engine 100 operate according to diesel engine principles, the exhaust gases have a slower exit velocity than spark ignited exhaust because all of the energy expended inside the combustion chamber 130: the spark ignited exhaust gases are still burning fuel as they exit the exhaust port 136, which can add to the noise.
As stated earlier, the opposed-piston engine 100 is dependent on the lubrication of its components. The lubrication of the various components of the opposed-piston engine 100 is dependent on the configuration of the engine case 104, to limit free space away from the two uniquely internal flywheels 330, 335. The engine case 104 is configured to isolate the compression cylinders 110 and combustion cylinders 130, which do not need lubrication due to the inviscid layer seal, from the crank case enclosure 105.
A lubricant 605 can be introduced into the crankcase 105 of the engine, as shown in
In an aspect, the flywheels 330, 335 and their associated pickup tubes 601 and hoses 602 and return tubes 603 and hoses 604 utilize Bernoulli's principle to create a pressure differential which draws the lubricating mist/vaporized lubricant out of the crankcase 105 and to other areas of the opposed-piston engine 100. More specifically, a parasitic drag created at the flywheel/lubricant interface creates a pressure differential that circulates vaporized lubricant to the valve cover areas 519 in order to lubricate the exhaust valve assembly 510. As shown illustrated in
The set of return tubes 603 and return hoses 604 are utilized to circulate the lubricating vapor back to the crankcase 105 from the area of the valve cover 519. In an aspect, the return tubes 603 and return hoses 604 are aligned such as to draw the vapor through parasitic drag by facing the opening of the return tube 603 away from the direction of the rotation of the flywheels 330, 335 so as to create low pressure in the return tube 603 and return hose 604 from the valve cover area 510. The opening of the return hose 604 within the valve cover 519 is properly situated away from the delivery side to facilitate vapor circulation in the valve cover 519. In an aspect, the return hoses 603 can be configured to be received through corresponding apertures in the engine case 104. In other aspects, the return hoses 603 can be configured to be attached to the exterior surface of the engine case 104 of the opposed-piston engine 100.
In an aspect, the combustion and purge cycle of the opposed-piston engine operates in the following fashion.
The crankshaft angle sensor initiates the operation of the fuel injector 132, with the control module controlling the continuous operation of the spark plug 131 and fuel injector 132 until the control module is commanded to stop the operation fuel injector 132. The spark plug ceases to operate once the detonation accumulator chamber 410 is charged and the engine 100 can then operate through compression ignition.
As the air compression piston 210 travels back and forth in the compression cylinder 110, actuated by the actions of the Scotch yoke base 205 and the connecting rod 211, ambient air is drawn through the one-way intake check valves 115, shown in
The intake port 137 between the accumulator chamber 120 and combustion cylinder 130 is properly sized and positioned to connect the two along the front side of the piston 230 during the combustion segment 130C and into the purge chamber 130P on the back side of the piston as it passes by in its circuit. As illustrated in
When the engine has run sufficiently to property charge the detonator accumulator system 400, the engine 100 will no longer have to rely on the spark plug 131 to remain running. Under operation of the detonator accumulator system 400, when the combustion piston 230 of segment 101 (side A) reaches the top of its stroke, at or past Top Dead Center (TDC), the components of the detonation accumulator valve assembly 420 associated with segment A (i.e., the push rod 421 extending into segment 101), opens and releases the stored high temperature and high pressure gases in the detonation accumulator 410, through the detonation aperture 428, into the combustion cylinder 130C, taking the fuel and air mixture past the point of detonation in the combustion cylinder 130C to begin the power stroke. The detonation accumulator valve assembly 420 keeps the detonation aperture 428 in place long enough to recharge the detonation accumulator chamber 410 in preparation for activation of the opposing engine section 102/side B. The use of the detonator accumulator system 400 creates a high compression ratio after TDC, without power loss due to high compression. The process can be repeated for both sides.
The push rod assembly 530 is actuated by the exhaust flywheel 330 which then pushes on the adjustment pivot 524 retained by the lock nut 525 to the rocker arm 521. The cam follower 526 on the other end 521a of the rocker arm 521 then actuates the exhaust valve 511. As the combustion piston 230 recedes through the power stroke, two events occur at the same time. The exhaust valve 511 opens at the top of the combustion cylinder 130, and more specifically the exhaust port 136, to allow the exhaust gases to escape into the exhaust manifold 540. At the same time, the purge recess 236 of the piston 230, see
After the combustion piston 230 has minimized the purge segment 130P, the combustion piston 230 bottoms out and begins the return compression stroke. The combustion piston 230 passes by both the intake port 137 and the purge port 138, isolating them both from the combustion chamber 130 and opening both up to the air accumulator chamber 120, to be refilled with air for the next cycle. As the combustion piston 230 continues to compress its air load, the fuel injector 132 begins to inject multiple short burst of fuel into the combustion segment 130C, to facilitate even mixing of the fuel and air in preparation for detonation at the top of the stroke. This action repeats as necessary.
As shown in
As shown in
The opposed-piston engine 100 described above provides for several improvements and advantages over other internal combustion engines known in the art. By combining the elements of spark ignited engines and compression ignited engines, the opposed-piston engine 100 takes the best attributes. For example, the opposed-piston engine 100 incorporates the efficient valves and the lubricant-less fuel of a four stroke “Otto Cycle” engine, with the power to weight ratio and the cylinder firing on each revolution of a “two Stroke engine” and the high torque and fuel detonation of a diesel engine.
In an aspect, since the opposed-piston engine 100 utilizes a spark plug 131 until the detonation accumulator chamber 410 is fully charged, the opposed-piston engine 100 is configured to operate at lower pressure than a diesel engine, which allows the fuel injectors to work with more than one type of fuel (e.g., diesel and gasoline), due to the different apertures in the injectors. In addition, since the opposed-piston engine 100 is configured to operate at low pressures, the opposed-piston engine 100 is easier to start than a high compression diesel engine, due to the lower compression ratio. Further, the opposed-piston engine 100 can operate at higher torque at high speeds due to the double fuel/air load and the fact that the load is detonated just past TDC. Likewise, the opposed-piston engine 100 can have a wide range of speed for the same reasons. In an aspect, the opposed-piston engine 100 can operate from idle to 4,500 RPMs with the assembly described above. In other aspects, described in more detail below, the opposed-piston engine can operate from idle to 25,000 RPMs when using a high-speed exhaust valve system.
By utilizing a Scotch yoke 205 to connect the two opposed combustion pistons 230, the opposed-piston engine 100 can run in either direction and any orientation. As discussed above, by connecting the combustion cylinders 230 rigidly to the Scotch yoke 205, which is held ridged but sliding alignment through the connection rods 211, 231 and guide shaft 207, the heads 230a of the combustion pistons 230 are closely aligned with the walls of the combustion cylinders 130, forming an inviscid layer between the two. An inviscid layer forms whenever there is a dynamic surface in contact with a fluid (air or water, etc.). The faster the velocity differential between the solid surface and the fluid, the tougher and thicker the inviscid layer becomes.
In addition, as discussed above, the rigid connection of the connecting rods 231 to the pistons 230 and the Scotch yoke 205 eliminate the need for wrist pins and pivoting members (reducing overall parts of the engine), with which the inviscid layer would not be able to be formed. The rigid connection of the combustion pistons 230 to the Scotch yoke 205 also is more energy efficient as the energy normally lost as a result of a poor crankshaft angle, which comes from the wrist pin/pivot combination, is recovered. Further, configuration of the opposed-piston engine 100 reduces noise and vibration: the rigid connection of the combustion pistons 230 eliminates piston slap, and reduces the overall number of parts as well.
Noise can be further reduced based upon the exhaust system. Because the exhaust gases are at 180 degrees opposed, the exhaust gas pressure wave can be made to cancel out most noise through the tuning chamber 550 where the two exhaust channels of the exhaust manifold 540 join into one. Further, the exhaust system 500 does not create a back pressure and does not consume power, using the operation of the crankshaft assembly 300, and more specifically the exhaust cam flywheel 330, to operate the exhaust system 500.
The inviscid layer forms a near frictionless seal between the walls of the combustion cylinders 130 and the heads 230s of the pistons 230 without the need of piston seals, which increases the efficiency of the engine 100, since piston seals can increase friction. The inviscid seal also enables the backside of the head 230a of the combustion piston 230 to be utilized to compress air to be used to fully purge exhaust gases from the combustion cylinder 130. By fully purging the combustion cylinders 130, a cleaner burn of the fuel occurs. Further, since there is zero to very minimal contact between the surfaces of the walls of the combustion cylinders 130 and the heads 230a of the combustion pistons 230, no combustion cylinder lubrication is necessary. Without cylinder lubrication, friction is reduced within the combustion cylinder 130 and pollutants in the exhaust are reduced.
The opposed-piston engine 100 described above also eliminates the need of external cooling. First, as described above, the engine 100 has reduced friction in the combustion cylinders 130, which reduces heat production. In addition, heat from the combustion cycle is reabsorbed after the fuel is detonated, releasing all of its energy at the moment of detonation just past top dead center. As the piston 230 recedes, the gases expand, absorbing heat, known as a refrigeration cycle. In an aspect, the refrigeration cycle can be made more effective by extending the stroke of the engine. The refrigeration cycle can also reduce the heat of the exhaust gases.
In addition, without the need of cylinder lubricant, and the reliance on the flywheels 330, 335 and their associated tubes 601, 603 and hoses 603, 604 under Bernoulli's principle discussed above, the need of lubricant pumps is eliminated. In an aspect, if the opposed-piston engine 100 above is designed to utilize diesel, the fuel is totally consumed at detonation and not burned in the exhaust system 500 as in spark ignited engines. In addition, the use of multiple fuel injectors 1132, as shown in
In an aspect, the alternative exhaust system 1500 is configured to allow of an exhaust valve to be cam-actuated in both directions. The cam actuated exhaust system 1500 comprises an exhaust valve assembly 1510, a rocker arm assembly 1520, and a push rod assembly 1530, and an exhaust manifold 1540. In an aspect, the cam actuated exhaust system 1500 is configured to operate with two cam flywheels 1330, 1335, both of which include cams 1330a, 1335 respectively, discussed in more detail below.
In an aspect, the exhaust valve assembly 1510 of the cam actuated exhaust system 1500 comprises an exhaust valve 1511, a stem 1512, a valve closer spring 1513, a valve keeper collar 1514, and valve collar set screws 1515, as illustrated in
In an aspect, the rocker arm assembly 1520 is configured to operate and control the operation of the exhaust valve assembly 1510. The rocker arm assembly 1520 comprises rocker arm bearing supports 1521, a rocker arm shaft 1522, an exhaust open actuator arm 1523, an exhaust close actuator arm 1524, and an exhaust valve actuator arm 1525. The rocker arm bearing supports 1521 of the rocker assembly 1520 are configured to rotationally support the rocker arm shaft 1522. The exhaust open actuator arm 1523, the exhaust close actuator arm 1524, and the exhaust valve actuator arm 1525 are configured to be secured to the rocker arm shaft 1522. In an aspect, the exhaust open actuator arm 1523 and the exhaust close actuator arm 1524 are oriented in opposite directions on the rocker arm shaft 1522. In an aspect, the three arms 1523, 1524, and 1525 are secured through locking pins 1528, which are received by corresponding apertures (not shown) within the rocker arm shaft 1522. Therefore, the three arms 1523, 1524, and 1525 rotate with the rocker arm shaft 1522, as discussed in more detail below.
Similar to the rocker arm 521 of the rocker arm assembly 500 discussed above, the exhaust open actuator arm 1523 and the exhaust close actuator arm 1524 are configured to receive an adjustment pivot 1526 secured with a lock nut 1527, as shown in
The exhaust valve actuator arm 1525 is configured to engage the exhaust valve assembly 1510, as shown in
The push rod assembly 1530 is configured to interact with the two flywheels 1330, 1335 and the rocker arm assembly 1520. The push rod assembly 1530 of accelerated exhaust system 1500 is similar to the push rod assembly 530 of the exhaust system 500 discussed above, but is configured to operate with an exhaust valve closing flywheel 1330 and an exhaust valve opening cam flywheel 1335. Both flywheels 1330, 1335 are configured to be placed on the respective ends of a crankshaft assembly 1330, as shown in
Each push rod 1531 includes a cam end 1531a and a pivot end 1531b. The cam end 1531a of the push rod 1531 is configured to engage the cams 1330a, 1335a of the respective flywheels 1330, 1335 in which with the rods 1531 interact. In an aspect, the cam end 1.531a of the push rod 1531 is configured to receive a cam follower 1532, as shown in
In an aspect, as shown in
In an aspect, as the exhaust valve closing flywheel 1330 and the exhaust valve opening flywheel 1335 rotate, the respective cams 1330a and 1335a oscillate the pushrods 1521 to alternately transmit the cam action to the corresponding actuator arms 1524 and 1523, causing the rocker arm shaft 1522 to rotate sufficiently to rotate the exhaust valve actuator arm 1525 up and down to open and close the exhaust valve 1511. Such a configuration allows the exhaust close actuator arm 1525 sufficient tolerance to avoid too tight of an adjustment that could cause the cam actuated exhaust system 1500 undo stress while facilitating a good seal when necessary.
For example, when a cam follower 1532 is engaged by the cam 1330a of the exhaust valve closing flywheel 1330, the pivot end 1531b of the push rod 1531 engages the adjustment pivot 1524 of the exhaust close actuator arm 1524, which rotates the exhaust valve actuator arm 1525, through the rocker arm shaft 1522, to close the exhaust valve 1511. Since the valve closer spring 1513 is accelerated by the action of the cam actuated exhaust system 1500, the spring 1513 has the inertia to facilitate closing the last small amount of the opening into the exhaust manifold 1540 to affect a seal.
When a cam follower 1532 is engaged by the extension 1335b of cam 1335a of the exhaust valve open flywheel 1335 and the cam follower 1532 is received by the indention 1330b of the valve close cam flywheel 1330, the pivot end 1531b of the push rod 1531 engages the adjustment pivot 1524 of the exhaust open actuator arm 1523, which rotates the exhaust valve actuator arm 1525, through the rocker arm shaft 1522, to open the exhaust valve 1511. The cam actuated exhaust system 1500 described above allows for high speed valve actuation, with the use of the cams to fully open and close the exhaust valve 1511, while accelerating the valve 1511 and valve closer spring 1513 to finish the last motion to create a seal. This prevents valve floating at high speeds.
In an aspect, the cam 1330a of the exhaust valve closing flywheel 1330 can be configured to be utilized by a high speed detonator accumulator system 1400 as illustrated in
The detonation accumulator valve assembly 1420 is configured to control the release of the gases from the detonation accumulator chamber into the combustion cylinder. In an aspect, the detonation accumulator valve assembly 1420 includes a push rod 1421, as shown in
In an aspect, the cam follower 1422 is configured to engage the cam 1330a of the exhaust valve closing flywheel 1330 as it rotates. In an aspect, the cam 1330a of the exhaust valve closing cam flywheel 1330 includes a cam follower raceway 1332 that is configured to receive the cam follower 1422. In an aspect, the cam follower raceway 1332 is circular in shape, but includes an indented portion 1333 that functions in a similar way as the cam 1330a (i.e., only applying pressure to the push rod 1421 when an extended portion engages the push rod in the rotation). The outer portion of the raceway 1332 acts to close the detonation aperture 1428 of the detonation valve assembly 1420. The cam follower mount 1423 can be configured to be an extension of the push rod 1421 configured to place the cam follower 1422 within the raceway 1332 without engaging the top surface of the closing cam 1330a. In an aspect, the cam follower mount 1423 can be thinner and flatter than the rest of the push rod 421 to ensure no interaction with itself and the surface of the closing cam 330a.
The chamber end 1421b of the push rod 1421 is configured to interact with the detonation accumulator chamber (not shown), by controlling the access of the detonation accumulator chamber to the combustion cylinder 1330 of the engine in the similar fashion a discussed above. The push rod 1421 includes a detonation aperture 1428 approximate the chamber end 1421b. When the indented portion 1333 of the cam follower raceway 1332 engages the cam follower 1422 of the flywheel end 1421a, the detonation accumulator valve assembly 1420 is configured to align the detonation aperture 1428 with the end of the detonation accumulator chamber adjacent the combustion cylinder to allow the hot and pressurized mixed gases into the combustion cylinder 1130. In an aspect, the chamber end 1421b is configured to receive a return spring (not shown) coupled to the engine case. When the return spring is fully extended (i.e., not compressed), the detonation aperture 1428 is not aligned with the detonation accumulator chamber. The race way 1332 of the cam 1330a opens and closes the valve assembly with each revolution of the cam 1330a.
As stated above, the opposed-piston engine 100 can be aligned and oriented in any fashion. In addition, multiple opposed-piston engines can be arranged in series with one another in various combinations as a result. The various combinations and alignments of the multiple opposed-piston engines can include, but are not limited to, the various combinations and orientations of engines shown in
While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention. To the extent necessary to understand or complete the disclosure of the present invention, all publications, patents, and patent applications mentioned herein are expressly incorporated by reference therein to the same extent as though each were individually so incorporated.
Having thus described exemplary embodiments of the present invention, those skilled in the art will appreciate that the within disclosures are exemplary only and that various other alternatives, adaptations, and modifications may be made within the scope of the present invention. Accordingly, the present invention is not limited to the specific embodiments as illustrated herein, but is only limited by the following claims.
This application claims priority from U.S. Provisional Patent Application 61/789,231, filed Mar. 15, 2013, which is relied upon and incorporated herein in its entirety by reference.
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Number | Date | Country | |
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61789231 | Mar 2013 | US |