WO1996035862A1

WO1996035862A1 - Bi-rotary engine

Info

Publication number: WO1996035862A1
Application number: PCT/NZ1996/000041
Authority: WO
Inventors: Murray Roulston
Original assignee: Murray Roulston
Priority date: 1995-05-10
Filing date: 1996-05-10
Publication date: 1996-11-14
Also published as: AU5518296A

Abstract

An engine including a casing (2), block means (5) being rotatable and a close fit within the casing (2), a cylinder (10) in said block means (5) housing a piston (12), a shaft (11) which is linked to the piston (12) such that movement of the piston (12) causes movement of the shaft (11) about an axis, said casing (2) carrying inlet means (6) which enables a supply of air or a mixture of fuel and air to be admitted to the cylinder (10), exhaust means (8) which enables exhaust gases to be released from the cylinder (10) and ignition initiation means (7) which can initiate ignition of fuel and air within the cylinder (10).

Description

BI-ROTARY ENGINE

This invention relates to an engine, and is applicable particularly, but not exclusively to a four-stroke cycle internal combustion engine.

According to one aspect of the invention there is provided an engine including a casing, block means being rotatabie and a close fit within the casing, a cylinder in said block means housing a piston, a shaft which is linked to the piston such that movement of the piston causes movement of the shaft about an axis, said casing carrying inlet means which enables a supply of air or a mixture of fuel and air to be admitted to the cylinder, exhaust means which enables exhaust gases to be released from the cylinder and ignition initiation means which can initiate ignition of fuel and air within the cylinder.

Conveniently the engine is adapted to operate on a compression ignition cycle, in which the ignition initiation means includes a fuel injector positioned to inject timed pulses of fuel into the cylinder.

Alternatively the engine is adapted to operate on a spark ignition cycle in which the ignition initiation means includes a spark plug of which the electrodes are exposed periodically into the cylinder.

Advantageously the inlet means includes an inlet port to convey air or a mixture of fuel and air from the exterior to the interior of the casing, the inlet port opening into an inlet chamber extending circumferentially within the casing adjacent the block means.

Desirably the exhaust means includes an exhaust port to convey exhaust gases from the interior to the exterior of the casing, the exhaust port opening into an exhaust chamber extending circumferentially within the casing adjacent the block means. The inlet and exhaust chambers may be separated by a land at the interior of the casing, the land being narrower than the diameter of the cylinder.

Preferably the shaft is a crankshaft connected to the piston in such a way that relative rotation between the block means and the crankshaft causes the piston to reciprocate in the cylinder between a top dead centre position and a bottom dead centre position.

Conveniently the piston is connected to the crankshaft by a connecting rod pivoted to the crankshaft and the piston.

The pistons and cylinders may be of any suitable cross-section, for example they may be of circular or oval cross-section.

Advantageously fixed ratio drive means interconnects the crankshaft, the block means and the casing, the drive ratio being arranged to bring the piston to the top dead centre position at one angular position of the casing at or adjacent the ignition initiation means for a two- stroke cycle engine and at two substantially diametrically opposite angular positions of the casing for a four stroke cycle engine, one of said two positions being at or adjacent the ignition initiation means and the other of said two positions being at or adjacent said land.

Preferably the casing and the block means have internal and external faces respectively which are circular in a cross section normal to the axis.

Conveniently, the interior surface of the casing around the block means is provided with a shell bearing.

Desirably, the block means carries a liner within and against the shell bearing. Preferably, a radially movable sleeve is a sliding fit in the outer end of the cylinder in the block means, to bear and seal against the facing surface of the casing or the shell bearing.

A spring mounted compression ring may be provided to surround the block.

A plurality of said cylinders and co-acting pistons may be evenly spaced circumferentially around the block means, and the block means may include at least two parallel banks of said cylinders.

Some preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, of which:

Figures 1 and 2 are each a cross-sectional view of a portion of an engine in accordance with the present invention,

Figure 3 is a partly cut-away perspective view of the exterior of the engine,

Figure 4 is a perspective view of a portion of a stainless steel liner which is incorporated in the engine,

Figures 5. 6 and 7 show the manner in which a connecting rod and a crank shaft of the engine are connected to one another,

Figure 8 is a part cross-sectional view, illustrating the connection of pistons to a crank¬ shaft.

Figure 9 is a plan view illustrating an alternative piston shape, and Figures 10 and 11 are schematic views illustrating the provision of an optional compression ring.

With reference to figures 1, 2 and 3, the engine has a head 1 comprising a stationery outer casing 2 which is circular in cross section. As shown in Figure 2, the casing 2 is formed from two half portions 2a and 2b which are each semi-circular in cross-section. The two half portions 2a and 2b are secured together by way of a bolt or bolts 3. As shown in Figure 3, the core of the casing 2 has a water channel 4 to facilitate cooling of the engine. The interior of the casing 2 is circular in cross-section and houses a block 5. The block 5 incorporates channels (not shown) for receiving a flow of oil to facilitate coding of the engine. Within the interior of the casing 2 and around the block 5 is a shell bearing 26. Additionally, a stainless steel liner 20 extends within and against the shell bearing 26.

As shown in Figure 1 , the engine includes an air or a fuel and air inlet port 6, a spark plug or a fuel injector 7, and an exhaust port 8. Within the liner 20 there are three combustion cylinders 10. The cylinders 10 are evenly spaced in a radial fashion about a central crankshaft 11. Within each cylinder 10 is a piston 12 which is connected to the crankshaft 11 by way of a connecting rod 13. Each piston 12 is associated with a dry liner 14, an outer compression expanding sleeve 15, and rings 16. The engine incorporates more than one bank of three cylinders, although only one bank is detailed in the interest of clarity. The inlet and exhaust ports 6, 8 extend circumferentially inside the casing 2 and are separated by a land 9, which is narrower than the diameter of a cylinder 10.

The engine is arranged such that the cylinders 10, the pistons 12, and the block 5 collectively rotate within the casing 2 when the engine is in use. Each cylinder 10 can in turn receive a supply of air or fuel and air when positioned adjacent the inlet port 6. As a cylinder 10 rotates towards the spark plug or fuel injector 7 the air or fuel and air is compressed by the respective piston. The fuel and air is ignited by the spark plug 7 or by injection of fuel by the fuel injector to cause the respective piston to move in a power stroke which causes rotation of the crankshaft 11. Further rotation of the cylinder 10 to the exhaust port 8 allows exhaust fumes to exit the cylinder.

With reference to figure 3, the crankshaft 11 is connected to a main drive sprocket 17. Rotation of the crankshaft 11 causes rotation of the main drive sprocket 17, which in turn causes rotation of a pilot sprocket 18. The pilot sprocket 18 is rotatabie on a spigot fixed ?.o the head 1 and engages an outer drive sprocket 19 which is fixed to the block 5. Rotation of the pilot sprocket causes rotation of the outer sprocket 19, which results in rotation of the block 5 to move the cylinders 10 around the ports 6 and 8 as described above.

With reference to figure 4, the stainless steel liner 20 incorporates oil sweepers 21 to prevent oil advancing into the inlet port 6 and the exhaust port 8.

Figures 5, 6 and 7 show one preferred way of arranging each connecting rod 13 with respect to the crankshaft 11. With particular reference to figure 5, it can be seen that an end portion of each connecting rod 13 extends around the crankshaft 11. The end portion of each connecting rod 13 includes an outer bearing cap 23 encasing a plurality of outer needle bearings 22. More particularly, the outer needle bearings 22 extend around the crankshaft 11. As shown in figure 5, a plurality of inner needle bearings 24 extend around and can roll against the crankshaft 11. More particularly, the inner needle bearings 24 are between the crankshaft 11 and the outer needle bearings 22. The arrangement of outer and inner needle bearings 22 and 24 allows movement of the connecting rods 13 with respect to the crank shaft 11. The arrangement is such that every one rotation of the block 5 corresponds with two rotations of the crankshaft 11. Figure 8 illustrates, schematically, one possible mechanism for mounting pistons 12a, 12b, 12c on the crankshaft 11 via a connecting plate 30. In this arrangement, each connecting rod 13 is pivotally connected with a respective piston 12a, 12b, 12c via a mounting pin 32, the innermost end of each connecting rod being secured to the connecting plate 30 via mounting pins 34.

As shown in Figure 9, the pistons 12, in one possible alternative arrangement may have a generally oval cross-section. The cross-section of the cylinders would, of course be adjusted accordingly. This arrangement facilitates the arrangement of rows of pistons in a multi-row arrangement, whilst minimising the overall dimension of the engine.

Figures 11 and 12 illustrate, schematically one possible arrangement in which a compression ring 36 is used to improve the ability of the piston/cylinder arrangements to hold compression during an engine cycle and to provide improved oil sealing characteristics. The compression ring 36 surrounds the periphery of the block 5 and is held in place, and set under compression by spring loaded mounting elements 38. As illustrated, by way of example, at 40 in Figure 10, the compression ring incorporates an opening to correspond with the position of the respective inlet part 6, spark plug or injector 7 and exhaust part 8.

In some embodiments of the invention certain parts of the engine may be formed from aluminium, plastics, and/or fibre carbon. This enables the engine to be relatively light weight when compared with many known engines. Those skilled in the art will appreciate that the engine described herein has advantages in that it incorporates relatively few moving parts.

While some preferred embodiments of the invention have been described by way of example it should be appreciated that improvements and modifications can occur without departing from the scope and spirit of invention.

Claims

WHAT I CLAIM IS:

1. An engine including a casing, block means being rotatabie and a close fit within the casing, a cylinder in said block means housing a piston, a shaft which is linked to the piston such that movement of the piston causes movement of the shaft about an axis, said casing carrying inlet means which enables a supply of air or a mixture of fuel and air to be admitted to the cylinder, exhaust means which enables exhaust gases to be released from the cylinder and ignition initiation means which can initiate ignition of fuel and air within the cylinder.

2. An engine according to claim 1 adapted to operate on a compression ignition cycle, in which the ignition initiation means includes a fuel injector positioned to inject timed pulses of fuel into the cylinder.

3. An engine according to claim 1 adapted to operate on a spark ignition cycle, in which the ignition initiation means includes a spark plug of which the electrodes are exposed periodically into the cylinder.

4. An engine according to any preceding claim, in which the inlet means includes an inlet port to convey air or a mixture of fuel and air from the exterior to the interior of the casing, the inlet port opening into an inlet chamber extending circumferentially within the casing adjacent the block means.

5. An engine according to any preceding claim in which the exhaust means includes an exhaust port to convey exhaust gases from the interior to the exterior of the casing, the exhaust port opening into an exhaust chamber extending circumferentially within the casing adjacent the block means.

6. An engine according to claim 5 in which the inlet and exhaust chambers are separated by a land at the interior of the casing, the land being narrower than the diameter of the cylinder.

7. An engine according to any preceding claim in which the shaft is a crankshaft connected to the piston in such a way that relative rotation between the block means and the crankshaft causes the piston to reciprocate in the cylinder between a top dead centre position and a bottom dead centre position.

8. An engine accordin to claim 7 in which the piston is connected to the crankshaft by a connecting rod pivoted to the crankshaft and the piston.

9. An engine according to claim 7 or 8 including fixed ratio drive means interconnecting the crankshaft, the block means and the casing, the drive ratio being arranged to bring the piston to the top dead centre position at one angular position of the casing at or adjacent the ignition initiation means for a two-stroke cycle engine and at two substantially diametrically opposite angular positions of the casing for a four stroke cycle engine, one of said two positions being at or adjacent the ignition initiative means and the other of said two positions being at or adjacent said land.

10. An engine according to any one of claims 1 to 9, in which the pistons and cylinders have a circular or an oval cross-sectional shape.

11. An engine according to any preceding claim in which the casing and the block means have internal and external faces respectively which are circular in a cross section normal to the axis.

12. An engine according to any preceding claim in which the casing is formed with internal coolant passages.

13. An engine according to any preceding claim in which the block means is formed with internal coolant passages.

14. An engine according to any preceding claim in which die interior surface of the casing around the block means is provided with a shell bearing.

15. An engine according to claim 14 in which the block means carries a liner within and against the shell bearing.

16. An engine according to any preceding claim in which a radially removable sleeve is a sliding fit in the outer end of the cylinder in the block means, to bear and seal against the facing surface of the casing or the shell bearing.

17. An engine according to any one of the preceding claims, further comprising a compression ring mounted to surround the periphery of the block.

18. An engine according to any preceding claim including a plurality of said cylinders and co-acting pistons, spaced evenly, circumferentially around the block means.

19. An engine according to claim 18 in which three cylinders are evenly spaced circumferentially around the block means.

20. An engine according to claim 16 or 17 in which the block means includes at least two parallel banks of said cylinders.

21. An engine constructed and arranged and adapted to operate substantially as described herein and as shown in the accompanying drawings.