Opposed piston engine

Abstract

An opposed piston engine includes approximately spherical combustion chamber formed by the two opposed pistons in a single cylinder and an intake manifold including gas hooks. The combustion chamber has a small cone shaped extension on each side leading to each of two opposed injectors located in the cylinder wall where the two pistons meet at the top of their stroke. The combustion chamber configuration reduces the surface area of the chamber and increases the burn length by a significant amount compared to known designs. The gas hooks in the intake manifold restrict the flow of exhaust gases into the intake manifold long enough for the pressure in the cylinder to blow down and the exhaust gasses to attain high velocity passing out through the exhaust manifold, allowing the intake ports to be uncovered before the exhaust ports.

Claims

1. A two strokes per cycle, internal combustion, direct injected, opposed piston engine comprising: at least two crankshafts rotationally coupled; at least two pistons traveling in opposite directions; at least one cylinder with intake ports toward one end of the cylinder and exhaust ports toward an opposite end of the cylinder, the intake and exhaust ports located so that the intake ports are opened first when the pistons are moving apart, and the intake ports are closed last as the pistons move inward; and an intake manifold covering the intake ports and having an internal shape comprising a circular gas hook region inside the intake manifold circling the cylinder and radially bordered by a concave gas hook wall, and laterally bordered by a gas hook reaching in from a manifold outer wall towards the intake ports and configured to reverse a direction of the flow of exhaust gases back towards the intake ports, for reducing exhaust gases flowing into the intake manifold; wherein the intake ports in the intake manifold are in fluid communication with ambient air at ambient air pressure.

2. The engine of claim 1, further including an exhaust manifold including a second inner shape for stopping exhaust gases from flowing back into the engine through the exhaust ports.

3. The engine of claim 2, wherein the inner surface shaped for stopping exhaust gases from flowing back through the exhaust ports is a gas hook in the exhaust manifold.

4. The engine of claim 1, wherein linear motion of the pistons is coupled to rotational motion of the crankshafts by Scotch yokes through followers residing in compression between the pistons and throws of the crankshaft, wherein springs reside in compression between the pistons and the throws, and the springs are compressed by motion of the pistons towards the throws reducing an impact load of combustion on the throws.

5. The engine of claim 4, wherein the pistons and Scotch yokes are guided by bearings mounted on the crankcases.

6. The engine of claim 1, wherein the combustion chambers formed by the shape of the tops of the pistons are almost spherical except for the tangent cone shaped portions extending on opposite sides to the cylinder where the fuel injectors are located.

7. The engine of claim 1, wherein air entering the engine through the intake ports is not obstructed by any form of intake valve at any time.

8. The engine of claim 1, wherein the pistons travel at a same speed and accelerate at a same rate.

9. The engine of claim 1, further including a squeeze area at the top of the each piston on each side of the combustion chamber that is at the same fifty to eighty degree angle with respect to the center axis of the cylinder.

10. A two strokes per cycle, internal combustion, direct injected, opposed piston engine comprising: at least two crankshafts rotationally coupled, the crankshafts including crankshaft throws converting linear to rotation motion; at least one cylinder between the crankshafts; at least two pistons traveling in opposite directions in the at least one cylinder and coupled to the crankshaft throws using Scotch yokes; springs residing in compression between the pistons and the throws, the springs compressed by motion of the pistons towards the throws reducing an impact load of combustion on the throws, wherein the pistons are fixedly attached to the Scotch yokes; and followers reside between the pistons and throws of the crankshaft, the followers conducting motion of the pistons to the throws.

11. The engine of claim 10, wherein the followers slide within the Scotch yokes between the pistons and the crankshaft throws and couple motion of the pistons to the crankshaft throws.

12. The engine of claim 11, wherein the springs reside between the pistons and the followers.

13. The engine of claim 12, wherein the sliding motion of the followers in the Scotch yokes is parallel with the motion of the pistons.

14. The engine of claim 1, wherein the intake manifold circumferentially surrounds the cylinder.

15. The engine of claim 1, wherein the intake manifold includes an intake air passage offset axially in the direction of piston motion from the circular gas hook region.

16. The engine of claim 1, wherein the circular gas hook region faces an inner portion of the intake ports first opened by outward motion of the pistons before the entire intake ports are opened.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:

(2) FIG. 1 is a cross-sectional top view depicting internal components of a one cylinder two piston opposed piston engine according to the present invention viewed with the pistons at Top Dead Center (TDC).

(3) FIG. 2 shows a cross-sectional front view of the opposed piston engine according to the present invention taken along line 2-2 of FIG. 1 viewed from the ends of the crankshafts with the pistons at Bottom Dead Center (BDC) exposing the large intake and exhaust ports in each end of the cylinder.

(4) FIG. 3 is a cross-sectional front view depicting internal components of a second embodiment of an opposed piston engine according to the present invention viewed in the direction of the rotational axis of the crankshafts with the pistons at BDC.

(5) FIG. 4 shows a cross-sectional view of the second embodiment of an opposed piston engine according to the present invention taken along line 4-4 of FIG. 3 with two of the pistons at BDC and the other two at TDC.

(6) FIG. 5 is a cross-sectional view of an exhaust manifold attached to either opposed piston engine according to the present invention through the longitudinal axis of the cylinder depicting a portion of the exhaust end of the cylinder without a piston, but with the exhaust manifold installed over the ports.

(7) FIG. 6 is a cross-sectional view of the exhaust manifold taken along line 6-6 of FIG. 5 through the ports and perpendicular to the longitudinal axis of the cylinder illustrating the flow path for exhaust leaving the cylinder. An exhaust gas hook 45 restricts a flow of exhaust back into the cylinder.

(8) FIG. 7 is a cross-sectional view of the intake manifold attached to either engine through the longitudinal axis of the cylinder depicting a portion of the intake end of the cylinder without a piston, but with the intake manifold installed over the ports.

(9) FIG. 8 is a cross-sectional view of the intake manifold taken along line 8-8 of FIG. 7 through the outer portion of the chamber and perpendicular to the longitudinal axis of the cylinder illustrating the air flow path into the cylinder.

(10) FIG. 9 is a perspective view of a piston according to the present invention.

(11) FIG. 10 is a cross-sectional view of two pistons according to the present invention.

(12) FIG. 11 is a second cross-sectional view of the two pistons according to the present invention.

(13) Corresponding reference characters indicate corresponding components throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

(14) The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims.

(15) FIG. 1 is a cross-sectional top view through the center of a first embodiment an internal combustion opposed piston engine 10, viewed from the top, depicting internal parts with pistons 14 at Top Dead Center (TDC). The opposed piston engine 10 has one cylinder 12, two pistons 14 each with a pin 16, two connecting rods 18 each with a journal bearing 20 on crankshaft throw 23, two crankshafts 22 each with a journal main bearing 24, two crankcases 26 and 28 each securely attached to one of the two different ends of cylinder 12, and an exhaust manifold 30 and an intake manifold 32 each surrounding cylinder 12. The two crankshafts 22 are connected together by gears, chains, or the like (not shown) to keep them turning at the same speed so that the pistons 14 each come together at the top of their stroke at the same time.

(16) The almost spherical combustion chamber 34 has the least possible area for its volume which reduces the heat transfer to its surroundings increasing the efficiency and power of each stroke. The squeeze area 36 and 38 at the top of each piston 14 on each side of the combustion chamber 34 are at the same angle with respect to the center axis of the cylinder 12, so that when the pistons 14 come together at the top of there stroke they squeeze the compressed air at high velocity into the combustion chamber 34 from each side in parallel directions. This causes a cyclone effect in the combustion chamber 34 with the vortex running from one side of the cylinder 12 to the other. Spraying fuel into this vortex reduces the fuel particle size, promotes complete combustion, increases power, and reduce the formation of NOx.

(17) FIG. 2 is also a cross-sectional front view of the engine 10, taken along line 2-2 of FIG. 1, viewed from the ends of the crankshafts, with the pistons at Bottom Dead Center (BDC). When the pistons 14 reach BDC the exhaust ports 40 and intake ports 42 are fully uncovered but as the pistons 14 move outward the intake ports 42 start to open first. This is made possible by the gas hook 44 creating a gas hook region 44a (see FIG. 7) in the intake manifold 32. As the intake ports 42 begin to open, the exhaust gases rush out into the gas hook 44 where they are turned around and block the gas from coming out of the intake until the exhaust ports 40 open and the exhaust pressure completely blows down.

(18) The gas hook 44 in the intake manifold 32 does not significantly restrict the flow of air into the cylinder 12. Therefore when the gasses rushing out through the exhaust system have built up enough momentum they are able to pull fresh air through the intake ports and completely scavenge and cool the cylinder from the inside. The intake ports 42 are partially open when the exhaust ports 40 close which gives the intake air time to compact into the cylinder 12 before the intake ports close, even at high speed.

(19) The two fuel injectors 46 in the side of the cylinder 12 spray fuel directly at each other through the cone shaped cavities 48 on each side of the spherical combustion chamber 34. This not only increases the burn length but it also promotes complete combustion by causing the fuel to be sprayed into an existing ball of flame coming from the other side.

(20) FIG. 3 is a cross-sectional front view depicting the internal parts of a second two cylinder opposed piston engine 50, viewed through the center of one of the cylinders in the direction of the rotational axis of the crankshafts with the pistons at bottom dead center (BDC). The engine 50 in FIG. 3 is the same as engine 10 in FIGS. 1 and 2 except that it has two cylinders and it does not employee a conventional rod to connect the piston to the crankshaft. The pistons 52 are rigidly connected to the Scotch yokes 54 which are guided by the roller bearings 56 on the crankshafts 58, the roller bearings 60 mounted on the crankcases 62, and the cylinders 64. The springs 66 are preloaded residing in compression between the followers 68 and the pistons 52 by the screws 70 that hold the Scotch yokes 54 and the pistons 52 together, and the followers 68 reside in compression between the throws 23 to couple linear motion of the pistons 52 to rotational motion of the throws 23. The preload on the springs 66 is just high enough for the maximum pressure in the cylinders 64 near Top Dead Center (TDC) at combustion to almost fully compress the springs 66 which takes the high impact load of the combustion off of the roller bearings 56. As the pistons 52 move away from TDC and towards Scotch yokes 54, the energy stored in the springs 66 is re-captured.

(21) FIG. 4 is a cross-sectional view of the engine 50 taken along line 4-4 of FIG. 3 and viewed from the top with one set of pistons 52 at BDC and the other at TDC. The crankshafts 58 are assemblies of four different parts, 58A, 58B, 58C, and 58D to allow the roller bearings to be pressed onto the shafts before they are assembled.

(22) FIG. 5 is a cross-sectional view of the exhaust manifold 30 of both engines 10 and 50 through the longitudinal axis of the cylinders 12 depicting a portion of the exhaust end of the cylinder 12 without a piston, but with the exhaust manifold 30 installed over the exhaust ports 40 and showing the exhaust ports 40 in the cylinder call 12a.

(23) FIG. 6 is a cross-sectional view of the exhaust manifold 30 taken along line 6-6 of FIG. 5 through the ports and perpendicular to the longitudinal axis of the cylinder illustrating the flow path for exhaust leaving the cylinder. A gas hook 72 is mounted over the exit port of the exhaust manifold 30 to stop any back flow of exhaust gases.

(24) FIG. 7 is a cross-sectional view of the intake manifold 32 for use on either engine 10 or 50 through the longitudinal axis of the cylinders 12 depicting a portion of the intake end of the cylinder 12 without a piston, but with the intake manifold 32 installed over the intake ports 42 and showing and intake path 33 and the intake ports 42 in the cylinder wall 12a, and a concave arced inner surface 33a of the intake manifold 32.

(25) FIG. 7 is a cross-sectional view of the intake manifold 32 attached to either engine 10 through the longitudinal axis of the cylinder 12 depicting a portion of the intake end of the cylinder 12 without a piston, but with the intake manifold 32 installed over the intake ports 42, and FIG. 8 is a cross-sectional view of the intake manifold 32 taken along line 8-8 of FIG. 7 through the outer portion of the chamber and perpendicular to the longitudinal axis of the cylinders 12 illustrating the air flow path into the cylinders 12. Air 80 entering the engine 10 through a radially extending intake air passage 82 in the intake manifold 32 is preferably at ambient air pressure and the engine 10 does not require any form or supercharging due to the combination of the intake manifold design (e.g., the gas hook 44) and the timing provided by the port 42 placement. The air 80 is preferable not obstructed by any form of valve. The gas hook 44 reaches in towards the intake ports 42 from a manifold outer wall 47 of the intake manifold and the gas hook region 44a has a concave gas hook region outer wall 33. The air 80 first enters an offset region 49 having a splitter 51 opposite to the passage 82, and then towards the intake ports 41.

(26) FIG. 9 is a perspective view of a piston 14 according to the present invention, FIG. 10 is a cross-sectional view of two pistons 14 and FIG. 11 is a second cross-sectional view of the two pistons 14. The pistons 14 include mating concave and convex top surfaces.

(27) While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.