TITLE

AN ENGINE AND A VALVE FOR AN ENGINE.

FIELD OF THE INVENTION

The disclosure invention relates to an engine and a valve for an engine.

For the purpose of explanation, reference will herein be made to use of the valve with respect to an internal combustion engine of the type having a single reciprocating piston, although it should be understood that the valve is not limited to applications involving either a single cylinder engine, or indeed an engine of the type that uses reciprocating pistons.

DESCRIPTION OF THE PRIOR ART

In this specification unless the contrary is expressly stated, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not to be construed as an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge; or known to be relevant to an attempt to sofve any problem with which this specification is concerned.

Various attempts have been made to replace the poppet valves utilized in a conventional internal combustion engine. Some of these utilize a rotating valve shaft such as that illustrated in United States Patent US 5,249,553 for instance. This valve scoops from one environment (such as the inlet air supply) and flings what is scooped up into a further environment (such as the combustion chamber). It is anticipated that this arrangement will be relatively inefficient.

As the person skilled in the art will note, that the timing and complications of the rotation will be critical for both the supply and injection, as well as receiving and

discharge of the combusted fuel is these prior known arrangement. As appropriate alignment of openings between the rotary shaft and inlet or outlet must take place twice or at least simultaneously at two locations.

The opening in the rotating shaft must first align with the supply and then rotate further to again discharge and vice versa. Even if the shaft has several openings, as there is no direct communication between the openings, timing must be spot on and alignment perfect if correct quantities are to be exchanged-

It would be particularly advantageous if a rotary valve could be provided for that had the supply or discharge of the various air, fuel, mixtures thereof and the like under a greater defined control

It is an object of the present invention therefore to, at the very least, provide a useful alternative to both known and the above-mentioned engine valve trains and the valves for these.

Other objects and advantages of the present invention will become apparent from the following description, taking in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

For the purpose of this specification the word "comprising" means "including but not limited to", and the word 'comprises' has a corresponding meaning.

SUMMARY OF THE INVENTION

In one aspect of the disclosure there is included a valve for an engine, the valve being a shaft defining an enclosed passageway passing at least part way there through said shaft, said passageway having a first end opening at or toward an end of the shaft, and a second end opening through a or the side of the shaft, the shaft being rotatabiy supported within a bore so as to be free to rotate therein said

bore, such that in use, continued rotation of the shaft periodically brings the second end of the passageway into alignment with a corresponding opening along the periphery of the bore for fluid communication with a combustion chamber of the engine, so that supply or discharge to and from the combustion chamber through the passageway takes place during the overlap of said second end opening of the shaft and the bore opening respectively.

Advantageously, in this arrangement both the supply or discharge into the combustion chamber is able to be handle by just the one overlapping alignment. Hence the define passageway can control the flow direction. As the person skilled in the art will appreciate the valve remains closed so long as the bore opening does align with the opening at the second end of the passageway.

Preferably the shaft includes along the circumferential sides of said shaft a carbon graphite sleeve so that the shaft is able to rotate within the bore without the requirement of lubrication.

Advantageously this means the engine will be able to operate at higher temperatures than one would expect for standard running engines with more exacting tolerances.

The passageway through the valve is in fluid communication with the combustion chamber and this allows gasses and or liquids may be passed between these.

Preferably, the first end of the passageway opens through the end of the shaft.

Preferably, the bore in which the valve is retained is located in the cylinder head of the engine.

Preferably, the second opening in the shaft is elongate, the direction of elongation of this opening being aligned with the direction of elongation of the shaft.

Preferably, the second opening in the shaft is a slot.

In a further aspect, the disclosure may include an engine including a valve as described above.

In a further aspect, the disclosure may include a head assembly for an engine including a valve as described above.

Preferably, the engine or head assembly for an engine utilises one of these valves as an inlet valve, and one as an outlet valve.

Preferably, the engine is of type having a reciprocating piston.

Preferably, in an alternative, the engine is a multi-cylinder engine.

Preferably, the first end of the passageway in the inlet valve is rn communication with a source of air and or fuel.

Preferably, the first end of the passageway in the outlet valve is in communication with an exhaust outlet.

Preferably, in an alternative, the passageway extends right through the valve, from one end to the other.

Preferably then, an inlet valve may be provided with a source of air and or fuel from both ends, and an exhaust valve may be in communication with an exhaust outlet at both ends

Preferably, the rotation of the or each valve is driven either directly or indirectly by the crankshaft of the engine.

In a further aspect, the disclosure may include a valve for an engine, the valve being a shaft having a passageway passing at least part way there through, said passageway having a first end opening at or toward an end of the shaft, and a second end opening through a side of the shaft, the shaft being retained in a bore

so as to be free to rotate therein, said bore being connected to a combustion chamber of the engine by either a further passageway or by intersecting the combustion chamber, such that in use, continued rotation of the shaft periodically brings the second end of the passageway through the valve into fluid communication with the combustion chamber of the engine.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawing. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate certain embodiments of the invention, and together with the description, serve to explain the principles of the invention.

Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for designing other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, to recognise that the claims should be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of this disclosure it will now be described with respect to an exemplary embodiment which shall be described herein with the assistance of drawings wherein:

Figure 1 is an upper perspective view of a cylinder head for an exemplary engine adapted to accept exemplary valves of the type discussed herein;

Figure 2 is a lower perspective view of the cylinder head in Figure 1 ;

Figure 3 is a perspective view of a pair or exemplary valves of the type discussed herein;

Figure 4 is an assembly view of an engine head assembly taken along line A-A as illustrated on the cylinder head illustrated in Figure 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to Figure 1 , where an exemplary embodiment of a cylinder head 7 for an internal combustion engine of the type that utilises a reciprocating piston is illustrated. Whilst the cylinder head illustrated is for a single cylinder engine, it should be understood that the invention could be adapted for rnulti cylinder engines also. This cylinder head 7 includes an inlet valve 1 and an outlet valve 2.

Each of these valves 1 and 2 is a shaft having a passageway passing at least part way there through, said passageway having a first end (6 in the case of the exhaust valve 2, and 14 in the case of the inlet valve 1) opening through an end of the shaft, and a second end opening through a side of the shaft (5 in the case of the exhaust valve 2, and 4 in the case of the inlet valve 1 ). Each shaft is retained in a bore 17 so as to be free to rotate therein, said bore being in communication with a combustion chamber 22 of the engine, such that in use, continued rotation of these shafts periodically brings the second end of the passageway into fluid communication with the combustion chamber of the engine sα that fuel, air and or exhaust may pass between these.

The air-fuel mixture is introduced into the cylinder head through the passageway through the inlet valve (1 ). The valve (1 ) is open at the inlet end of the valve (14)

and the air-fuel mixture travels through the passageway in the valve and into the combustion chamber via a port (4) at the second end of the passageway in the valve. The top of the combustion chamber (22) incorporates ports (15) and (16) which are the same size and shape as the inlet and exhaust valve ports (4) and (5). Once combustion has occurred gases are exhausted from the combustion chamber via the exhaust rotary valve (2) port (5) at the second end of the passageway in the valve 2 allowing exhaust gases to move through passageway through the exhaust valve 2 to the open end of the exhaust valve (6).

Sealing of the combustion chamber is achieved by sealing rings (3) which are located in grooves (3a) in the inlet valve (1 ) and exhaust valve (2) on each side of the inlet valve port (4) and exhaust port (5). The sealing rings (3) are designed to sit against the inside of the cylinder head bores (17) and be stationary while the valves (1 ) and (2) rotate. The seals are of one piece but split at one place by a 45 degree cut (18) this allows the seals to be placed onto the valves and slid into the grooves (3a) before the valves are assembled into the cylinder head (7).

Each valve (1) and (2) is lubricated by oil that is fed through oil galleries (12) located within the cylinder head (7). The lubricating oil is sealed within the head by oil seals (11) located in grooves in the inlet and exhaust valves (1 ) and (2).

Nonetheless as discussed above in other preferred embodiments the shaft includes along the circumferential sides of said shaft a carbon graphite sleeve so that the shaft is able to rotate within the bore without the requirement of lubrication. As discussed this means the engine will be able to operate at higher temperatures than one would expect for standard running engines with more exacting tolerances.

The valves (1 ) and (2) rotate within the cylindrical bores (17) located in the cylinder head (7) and a bearing (8) is located on the end of each shaft to locate the shaft within the cylinder head bores (17). The bearings (8) are held in place by housing plates (9) and (10) which are fixed tα the cylinder head (7). The valves (1) and (2)

are driven via timing sprockets (13) which are locked onto the inlet and exhaust valves (1 ) and (2). The tinning sprockets are driven from the engines crankshaft in much the same way that a camshaft of an engine utilising poppet valves may be driven.

Advantages of this valve and an engine using the same include:

Manufacturing - The cylinder head requires less parts than a conventional cylinder head and all the parts can be manufactured using simple, conventional manufacturing techniques. The cylinder heads could be manufactured by casting and machining or machined from a solid billet or from an extrusion. Because there are no curved induction or exhaust ports within the cylinder head the machining operation is greatly simplified when compared to a conventional cylinder head. Because it is possible to manufacture the cylinder head and valves without a casting process it would be possible to use unconventional but thermally efficient materials to manufacture these components.

Compactness - The cylinder head is relatively compact when compared to an overhead cam or overhead valve 4-stroke cylinder head design. Because the outside diameter of the valves can be less than the height of a conventional valve the cylinder head does not need to be as tall as a conventional cylinder head. Also the rotary valve cylinder head does not require any overhead vafve gear to be covered or protected from the surrounding environment.

Increased compression ratio -The engine can be successfully run with a higher compression ratio than an engine with the same displacement. A higher compression ratio increases the volumetric efficiency of the engine.

Valve Timing adjustment and valve maintenance - The rotary valve timing can be easily adjusted without removing the cylinder head from the engines cylinder block. The rotary valves can also be removed and replaced without removing the

cylinder head from the cylinder block. Adjustment of valve timing is also relatively easy.

Smoother valve gear operation - Because the rotating action of the valves replaces the reciprocating action of a conventional engines valve gear some 5 vibration has been removed from the engine.

Damage minimization - Should there be a failure of the valve driving chains and the valves stop rotating the engine will stop running but there will be no further damage to the engines pistons, con-rods or crankshafts. In a conventional engine, a failed cam chain or cam-belt could result in pistons hitting valves and 10 causing major damage to the engines internal components.

Less valve gear wear - The relatively large surface area ot the rotary valve will help dissipate heat into the cylinder head and reduce wear on the valve surface.

Although the disclosure has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that 15. departures can be made within the scope of the invention, which is not to be limited to the details described herein but is to be accorded the full scope of the appended claims so as to embrace any and all equivalent devices and apparatus-