GB2146699A

GB2146699A - Opposed piston i.c. engine

Info

Publication number: GB2146699A
Application number: GB08422825A
Authority: GB
Inventors: Seamus Gearoid Timoney
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-09-13
Filing date: 1984-09-10
Publication date: 1985-04-24
Also published as: GB8422825D0; IE832140L; AU3296784A

Abstract

The cylinder (3) containing opposed pistons (4) rests on a pair of support members (5) which are fastened to a sump (2). The support members (5) rotatably support rocker shafts (15) and a crank shaft (10). Connecting rods (11 and 12 Fig. 3) deliver drive from the pistons (4) through the rocker arms (14) to the crank shaft (10). N cylinders may be supported on N + 1 support members within the sump. <IMAGE>

Description

SPECIFICATION An internal combustion engine The present invention relates to an engine, and in particular to an internal combustion engine.

One problem with internal combustion engines, whether two stroke or four stroke, petrol, gas or diesel driven, is that there is very little interchangeability of parts between engines of different power outputs, for example, if one has a single cylinder engine or a four cylinder engine, there is virtually no interchangeability of parts with the exception of, perhaps, pistons and connecting rods. Additionally, other than marginal changes in the power output, it is impossible to increase the power output to any significant extent of an engine. Thus, if one requires more power, it normally means scrapping the existing engine and replacing it with a heavier engine.

Furthermore, where it is desired to stock engine covering a large range of power outputs, it is necessary to stock a large number of engines, each with their own individual power output. This, it will be appreciated, leads to considerable inefficiencies, and additional costs on the part of the user, and in particular, it requires suppliers to retain large stocks with the consequential high costs of carrying such stock.

There is therefore a need for an engine which overcomes these problems.

According to the invention there is provided an engine constructed in modular form comprising a cylinder for a pair of opposed pistons, support means to support the cylinder, a pair of rocker shaft carrying means being provided in the support means to support a pair of rocker shafts associated with the opposed pistons.

In one embodiment of the invention a crank shaft bearing support means is provided in the support means.

In another embodiment of the invention the crank shaft bearing support means is provided intermediate the rocker shaft carrying means and spaced-apart from a centre-line joining the rocker shaft carrying means.

Preferably the rocker shaft carrying means are provided at two opposing ends of the support means.

In one embodiment of the invention each rocker shaft carrying means is provided by a split clamp, one half of which is integral with the support means, and the other half being connected thereto by fastening means.

Alternatively, each rocker shaft carrying means is provided by a bearing support means.

Advantageously, each rocker shaft bearing support means is provided by a split bearing, one half of which is integral with the support means, and the other half being connected thereto by fastening means.

Preferably, the crank shaft bearing support means is provided by a split bearing, one half of said split bearing being integral with the support means, and the other half being connected thereto by fastening means.

In another aspect of the invention the support means for supporting the cylinder is provided by a single integral member.

Additionally, the invention provides a support means for the cylinder of the engine.

The advantages of the invention are many, however, one particular advantage of the invention is that an engine can be provided, the power output of which can readily easily be increased or decreased over a wide range of power outputs. This is because the engine is essentially provided in modular form, and by merely adding to or taking from the number of cylinders and support members, the power output of the invention can be increased.

Another advantage of the invention is that a large number of the components are interchangeable between engines of varying power outputs. Indeed, the only components which are not common are the crank shaft, the cam shaft, the sump and the sump cover. However, where it is desired to decrease the power output of an engine, all that is required is to remove the required number of cylinders and support means, and purchase a new sump, crank shaft and cam shaft. Similarly, where it is desired to increase the power output, all that is required is to add the required number of additional cylinders and support members, and obtain a new sump, crank shaft and cam shaft. Thus, it will be appreciated that a stockist may considerably reduce his stock of engines by virtue of the fact that by adding to or subtracting from the number of cylinders, engines of varying power output may be provided.This, it will be appreciated is a further very important advantage of the invention. Thus, the only noncommon parts that a stockist has to stock are crank shafts, rocker shafts and sumps.

The invention will be more clearly understood from the following description of some preferred embodiments thereof given by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a modular engine according to the invention; Figure 2 is a perspective view of the engine of Fig. 1 with the cover removed; Figure 3 is a front elevational view of portion of the engine of Fig. 1; Figure 4 is an end view of portion of the engine of Fig. 1; Figure 5 is a perspective view looking down on the engine with portion of the engine removed; Figure 6 is a perspective view of portion of the engine of Fig. 1; and Figure 7 is a view similar to Fig. 4 of an engine according to another embodiment of the invention.

Referring to the drawings, and initially to Figs. 1 to 6, there is provided a single cylinder two stroke diesel engine according to the invention, indicated generally by the reference numeral 1. The engine is of modular construction and comprises a sump 2 of cast aluminium, and a cylinder block 3 with a pair of opposed pistons 4. The cylinder block 3 is supported on a support means, in this case, a pair of support members 5 of high strength iron. Legs 7 cast integrally with each support member 5 extend downwardly and rest on seats 8 in the sump. The legs 7 are secured thereto by screws 9.

The pistons 4 drive a crank shaft 10 through connecting rods 11 and 1 2, and rockers 14. The rockers 14 pivot on rocker shafts 15, which are supported in carrying means, in this case, split bearings 1 6, one half of which is cast integrally with each support member 5. The second half 1 7 of each split bearing 16, also of cast iron, is secured by studs 18. A split bearing 19, one half of which is cast integrally with each support member 5 carries the crank shaft. The half 20 of each bearing 1 9 is secured by studs 21.

It will be appreciated that because both rocker shafts 1 5 are carried on the same pair of support members 5, the opposing forces between the rocker shafts are carried by the support members 5. Therefore, there is no question of any forces being carried by any other parts of the engine, for example, the sump, cylinder block, crank case or the like.

This, it will be appreciated, has been a considerable problem with these type of engines which have been manufactured heretofore.

In this embodiment of the invention, the cylinder block 3 is air cooled, and cast from aluminium with cooling fins 24. Inlet and outlet ports 25 and 26 respectively, are also provided. Cover plates 27 enclose the sides of the cylinder block 3. Cylinder sleeves 28 are inserted in the cylinder block 3. A drive 29 on a shaft 35, driven by sprockets 30 and chain 31 from the crank shaft 10, is provided for a fuel injection pump (not shown). Needless to say, other drives could similarly be provided, for example, for a super charger or the like.

Furthermore, a cam or cams could be located on the shaft 35 to operate a fuel injection pump directly.

A cover 33 to house the engine parts is secured to the sump 2 by screws 34.

To assemble the engine, the crank shaft 10 is secured in the bearings 1 9 in support members 5. The connecting rods 12, rockers 14, rocker shafts 1 5 are assembled to the support members 5. The support members 5 are then secured to the sump 2. The cylinder 3 with pistons 4 and connecting rods 11 assembled is placed in position on the edges 6 of the support members 5. The connecting rods 11 and rockers 1 4 are connected. Because there are no lateral or transverse forces acting on the cylinder block 3, it will be appreciated it is not necessary to secure it to the support members 5. It merely rests on the edges 6. The remaining components are then assembled in conventional manner.

Referring now to Fig. 7 a two stroke diesel engine 40 according to another embodiment of the invention, is illustrated. In this case, the engine also is of modular construction and comprises three cylinders, and other than that is substantially similar to the engine 1 of Figs.

1 to 6. Accordingly, similar components are identified by the same reference numerals. In this case, each cylinder 3 is supported on a pair of support members 5, and as can be seen, there are four support members 5, in other words, one more than the number of cylinders. It will therefore be appreciated that using the principle of the present invention, to construct an engine of N cylinders, N + 1 support members are required. This, it will be appreciated, leads to the great advantage of having considerable interchangeability of parts between engines of differing numbers of cylinders. In fact, all that is required to add an additional cylinder or any number of cylinders to any particular size of engine, is to add the desired number of cylinders, which are all similar to each other, and the required number of support members, which are also similar to each other.The only parts that aren't common are the sump, which has to be extended longitudinally to accommodate the additional cylinders, the crank shaft and rocker shafts. Thus, to supply varying sizes of engine according to the present invention, it is only necessary to stock varying sizes of crank shaft, rocker shafts and sumps. The remaining components are common irrespective of the number of cylinders used.

Further, it will be appreciated that since the sump 12 is of cast aluminium, by merely inserting spacers in the pattern, larger sizes of sumps can be cast. The end sections are common irrespective of the number of cylinders used in the engine.

It will of course be appreciated that although the engines described above are described as being of fixed compression ratio, variable compression ratio engines could readily easily be constructed, for example, by providing rocker shaft with eccentric bearings, or indeed any other suitable means of varying the compression ratio could be used, which will be well known to those skilled in the art.

It will also be appreciated that the engine, instead of being air cooled, could if desired be water cooled or non-cooled if made of a high temperature material. Again, this will be readily apparent to those skilled in the art.

It is envisaged in certain cases, that the support members may be constructed with a pair of rocker shaft bearings spaced-apart on a support member. The advantages of the pre sent invention would still be achieved, in that all the forces exerted bathe rocker shaft would be carried in the support member. In certain cases, it is envisaged that the rocker shaft bearing may be mounted on a support member which may be formed from a threaded bar. The compression ratio could thus be varied by rotating the threaded bar, thereby moving the rocker shaft relative to each other. Needless to say, the threaded bar would have opposing threads for each rocker shaft bearing. In this case, it is further envisaged that the crank shaft support bearing would be mounted on the bar substantially centrally.

Further, it is envisaged that the rocker shaft support bearings could be mounted on a bar, and movable relative to each other by hydraulic or pneumatic means. In act, if desired the support members could be constructed in the form of a framework. Again, these variations will be readily apparent to those skilled in the art.

While the various components of the invention have been described as being of particular shape and construction, other suitable shapes and construction could be used without departing from the scope of the invention.

In fact, it will be appreciated that if desired, the support members, instead of being secured to the sump, could be mounted on a framework. Indeed in certain cases it is envisaged that it may not be necessary to fasten the support members to the sump.

Furthermore, it will be appreciated that the invention could be used with any type of engine besides a two stroke diesel, for example, any type of two stroke or four stroke internal combustion engine could be used, powered by petrol, gas, diesel or other fuel.

While the sump has been described as being of cast aluminium it could be of any other suitable material or construction, for example, it could be a steel pressing, a reinforced plastic, or the like.

Furthermore, while the support members 5 have been described as being cast of high tensile iron, they could be of any other cast material, they could be fabricated from steel, or any other suitable material, or they could be formed by a pressing. Further, it is envisaged that the support means, instead of being a support member as already described, could be a framework or any other suitable member.

Additionally, it will be appreciated that while the rocker shaft carrying means has been described as being a split bearing, any other bearing means could be used. for example, the bearing means may be a complete bearing formed integrally with the support means. Indeed, it will be appreciated that it is not necessary for the carrying means to be a bearing, it could if desired be any other suitable carrying means, for example, it could be any other clamping arrangement formed integrally or otherwise with the support means. It may be a split clamp, one half of which being cast integrally with the support means and the other half being fastened thereto.

Claims

1. An engine constructed in modular form comprising a cylinder for a pair of opposed pistons, support means to support the cylinder, a pair of rocker shaft carrying means being provided in the support means to support a pair of rocker shafts associated with the opposed pistons.

2. An engine as claimed in claim 1 in which a crank shaft bearing support means is provided in the support means.

3. An engine as claimed in claim 2 in which the crank shaft bearing support means is provided intermediate the rocker shaft carrying means and spaced-apart from a centre-line joining the rocker shaft carrying means.

4. An engine as claimed in any preceding claim in which the rocker shaft carrying means are provided at two opposing ends of the support means.

5. An engine as claimed in any preceding claim in which each rocker shaft carrying means is provided by a split clamp, one half of which is integral with the support means, and the other half being connected thereto by fastening means.

6. An engine as claimed in any of claims 1 to 4 in which each rocker shaft carrying means is provided by a bearing support means.

7. An engine as claimed in claim 6 in which each rocker shaft bearing support means is provided by a split bearing, one half of which is integral with the support means.

and the other half being connected thereto by fastening means.

8. An engine as claimed in any preceding claim in which the crank shaft bearing support means is provided by a split bearing, one half of said split bearing being integral with the support means, and the other half being connected thereto by fastening means.

9. An engine as claimed in any preceding claim in which the support means for supporting the cylinder is provided by a single integral member.

1 0. An engine as claimed in any preceding claim in which each support member is provided by a casting.

11. An engine as claimed in claim 10 in which the rocker shaft carrying means and the crank shaft bearing support means are cast integrally with the support member.

1 2. An engine as claimed in claim 8 or 9 in which each support member is cast of high strength iron.

1 3. An engine as claimed in any of claims 9 to 1 2 in which a pair of support members are provided to support a cylinder.

14. An engine as claimed in any of claims 9 to 1 2 in which a plurality of cylinders, namely, N cylinders are provided and a plurality of support members, namely, N + 1 support members are provided to support the cylinders.

1 5. An engine as claimed in any of claims 9 to 14 in which a pair of support legs extend from each support member.

1 6. An engine as claimed in claim 1 5 in which a sump is provided and the legs of each support member engage corresponding seats provided in the sump.

1 7. An engine as claimed in any preceding claim in which a pair of opposed pistons are provided in each cylinder, each piston being connected to a corresponding rocker on a rocker shaft rotatable in the carrying means by a connecting rod, and a crank shaft is provided in the crank shaft bearing means and is driven by connecting rods from the rockers.

18. An engine as claimed in claim 1 7 in which a timing shaft is provided, the timing shaft being drivable from the crank shaft.

1 9. An engine as claimed in claim 1 8 in which the timing shaft is rotatable in the sump, and driven by a chain and sprocket drive.

20. An engine as claimed in any preceding claim in which the engine is a two-stroke diesel engine.

21. An engine substantially as described herein with reference to and as illustrated in the accompanying drawings.

22. A support means for a cylinder or an engine as claimed in any of the preceding claims.

23. A support means for an engine substantially as described herein, with reference to and as illustrated in the accompanying drawings.