FIELD OF THE INVENTION

This invention relates to an internal combustion engine. More particularly, but not exclusively, the invention relates to an internal combustion engine, for example with multiple banks of cylinders, with improved cost-effectiveness through the use of common engine parts.

BACKGROUND OF THE INVENTION

It is known to provide an internal combustion engine for powering items such as a vehicle, generator, machinery or the like. Traditional conventional internal combustion engines use a crankshaft, crankpins and connecting rods. However the applicant has identified that there are limitations in noise, vibration, smoothness, efficiency and emissions of conventional internal combustion engines.

In many traditional engines, especially V-configured engines, opposed engines or boxer engines, the engine is made up of major components that are unique to the left or right side of the engine. For example, the cylinder head will be different on the right bank versus the left bank, and the engine block will be different on the left bank versus the right bank. These parts are not only different in their machined form but also different in their original cast form. This requires separate dies, tooling and fixtures/jigs in order to make, machine and use these parts. On top of this, the surrounding parts are also affected by the non-commonality, things like gaskets, mounting faces and accessory parts. Some manufacturers have gone to length to "commonise" some of the major part mounting faces to enable the use of more common pieces but not to the extent as proposed with the present invention.

The applicant has determined that it would be beneficial for there to be provided an internal combustion engine which overcomes or at least alleviates one or more disadvantages of existing engines, while providing an engine which is more cost- effective to produce. Accordingly, examples of the present invention seek to avoid or at least ameliorate the disadvantages of existing internal combustion engines.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there is provided an internal combustion engine, including a piston, a cylinder, and an output shaft, wherein the piston is arranged for reciprocating motion within the cylinder, driven by combustion, and the piston is coupled to the output shaft by a coupling such that said reciprocating motion of the piston drives rotation of the output shaft, wherein the engine has increased engine part commonality.

Preferably, the engine includes a first cylinder bank and a second cylinder bank, wherein the first cylinder bank has a first cylinder head, the second cylinder bank has a second cylinder head, and wherein the first cylinder head and the second cylinder head are formed as common parts such that they are interchangeable.

More preferably, the first cylinder head and the second cylinder head are formed as common castings such that they are interchangeable parts.

Preferably, the engine includes a first cylinder bank and a second cylinder bank, wherein the first cylinder bank has a first cylinder block, the second cylinder bank has a second cylinder block, and wherein the first cylinder block and the second cylinder block are formed as common parts such that they are interchangeable.

More preferably, the first cylinder block and second cylinder block are formed as common castings such that they are interchangeable parts.

Preferably, one end of the engine is provided with a first mounting part for mounting other components and an opposite end of the engine is provided with a second mounting part for mounting other components, and wherein the first mounting part and the second mounting part are formed as common parts such that they are interchangeable.

More preferably, the first mounting part and the second mounting part are arranged with a mounting face for coupling to a transmission, generator or other device.

Even more preferably, the first mounting part and the second mounting part are arranged to couple a transmission to one end of the vehicle and an electric motor or generator to the opposite end of the engine.

Preferably, the engine includes a first cylinder bank and a second cylinder bank, wherein drive for a camshaft of the first cylinder bank from the crankshaft is at one end of the crankshaft, and wherein drive for a camshaft of the second cylinder bank from the crankshaft is at an opposite end of the crankshaft.

In one form, the coupling is arranged such that the piston has sinusoidal motion for constant rotational velocity of the output shaft when plotted against rotational angle of the output shaft. More preferably, the engine is in the form of an opposed cylinder engine.

In accordance with another aspect of the present invention, there is provided an internal combustion engine, including a plurality of pistons, a plurality of cylinders, and an output shaft, wherein the pistons are arranged for reciprocating motion within the cylinders, driven by combustion, and the pistons are coupled to the output shaft by a coupling such that said reciprocating motion of the piston drives rotation of the output shaft, wherein the engine includes a first cylinder bank and a second cylinder bank, wherein drive for a camshaft of the first cylinder bank from the output shaft is at one end of the output shaft, and wherein drive for a camshaft of the second cylinder bank from the output shaft is at an opposite end of the output shaft.

In accordance with yet another aspect of the present invention, there is provided an internal combustion engine, including a piston, a cylinder, and an output shaft, wherein the piston is arranged for reciprocating motion within the cylinder, driven by combustion, and the piston is coupled to the output shaft by a coupling such that said reciprocating motion of the piston drives rotation of the output shaft, wherein the engine includes an engine cylinder block formed as separable parts, being a crankcase and at least one cylinder block.

In accordance with yet another aspect of the present invention, there is provided an internal combustion engine, including a piston, a cylinder, and an output shaft, wherein the piston is arranged for reciprocating motion within the cylinder, driven by combustion, and the piston is coupled to the output shaft by a coupling such that said reciprocating motion of the piston drives rotation of the output shaft, wherein the engine includes a crankcase formed of a plurality of separable like parts, each of the like parts being cast as a common part. Preferably, each of the like parts is an identical part. More preferably, each of the like parts is cast from a common mould.

In a preferred form, the crankcase is formed of a pair of said separable like parts, such that each of said separable like parts is a half of the crankcase. More preferably, the engine further includes a plurality of cylinder blocks, each of the cylinder blocks being formed as a common part.

Preferably, the engine further includes a plurality of cylinder heads, each of the cylinder heads being formed as a common part.

In accordance with yet another aspect of the present invention, there is provided a method of forming an engine as described above, the method including the step of casting the crankcase halves as similar parts; machining the castings, and coupling together the crankcase halves to form the crankcase.

Preferably, the step of coupling together the crankcase halves is performed by bolting together said crankcase halves.

In a preferred form, the method further includes the step of final machining a crankshaft bore in the crankcase subsequent to the step of coupling together the crankcase halves.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of non-limiting example only with reference to the accompanying drawings, in which:

Figure 1 shows a perspective front view of an opposed cylinder engine using different cylinder heads and block castings on each cylinder bank;

Figure 2 shows a perspective rear view of the opposed cylinder engine shown in Figure 1;

Figures 3 to 7 show various views of an internal combustion engine in accordance with an example of the present invention, depicting an example engine layout with virtually identical front and rear views; Figure 8 shows a perspective view of the internal combustion engine of Figures 3 to 7, showing common heads and blocks;

Figure 9 shows a bottom view of the internal combustion engine of Figures 3 to 8;

Figure 10 shows a perspective view of the internal combustion engine of Figures 3 to 9, with a mounting plate fitted to each of the front end and rear end of the engine;

Figure 11 shows a detailed review of a cylinder head of the internal combustion engine of Figures 3 to 10, showing a common head with timing gear access;

Figure 12 shows various views (a to f) of crankcase halves of the engine and a cylinder block of the engine in accordance with another example of the invention;

Figure 13 shows a partially disassembled perspective view of the engine, depicting fitment of a piston within a cylinder;

Figure 14 shows a cutaway view of a proposed bolt concept for an example of the engine;

Figure 15 shows a top view of a cylinder block;

Figure 16 shows a perspective view of a crankcase half of the engine in accordance with the example shown in Figure 14;

Figure 17 shows a perspective view of an aluminium cylinder block with water jacket of the example shown in Figure 14;

Figure 18 shows a cam arrangement of a single overhead camshaft with low head height in comparison with an existing double overhead camshaft arrangement for reference;

Figure 19 shows a front view of a preferred drive arrangement layout overview with a single camshaft per cylinder bank design;

Figure 20 shows a rear view of the drive arrangement shown in Figure 19; and

SUBSTITUTE SHEET (RULE 26) Figure 21 shows a top view of the drive arrangement shown in Figures 19 and 20.

DETAILED DESCRIPTION

As can be seen in Figures 1 and 2 of the drawings, in many traditional engines, the engine 10 is made up of major components to the left or right side of the engine 10. In particular, Figure 1 shows a front view of the engine 10 showing a timing belt for coupling camshafts of the engine 10 to a crankshaft of the engine 10, whereas Figure 2 shows a rear view of the engine 10. The engine 10 has many parts that can only be used on one side of the engine 10 and are not interchangeable.

In the example shown, the engine 10 of Figures 1 and 2 of the drawings is in the form of a previously proposed opposed cylinder engine. In this engine 10 as depicted, the cylinder head 12 will be different on one cylinder bank 14 versus an opposite cylinder bank 16, and the engine 10 will be different on one cylinder bank 14 versus the opposite cylinder bank 16. This leads to inefficiencies as these parts are not only different in their machined form but also different in their original cast form, therefore requiring separate dies, tooling and fixtures/jigs in order to make, machine and use these parts. Moreover, the surrounding parts are also affected by the non-commonality. Specifically, items like gaskets, mounting faces and accessory parts must be specially designed and manufactured for each different cylinder bank.

With reference to Figures 3 to 11 of the drawings, there is shown an internal combustion engine 18 in accordance with an example of the present invention. Advantageously, the internal combustion engine 18 shown in figures 3 to 11 has improved commonality of parts such that there can be less part tooling, common castings, less machining, and the ability to interchange parts in production and in the field. Other advantages are also discussed throughout this document. In particular, Figures 3 to 7 show various views of the engine 18, showing the proposed engine layout with virtually identical front and rear views (see Figure 3 and Figure 4A). Only the shape of the sump 56 and location of the filter 54 give an indication as to which end of the engine 18 is the front and which end of the engine 18 is the rear. Figure 4B shows an additional rear view of the engine 18, similar to the view in Figure 4A but from a slightly different perspective so as to show the filter 54. The internal combustion engine 18 of the present invention includes a piston 20, a cylinder 22, and an output shaft 24, wherein the piston 20 is arranged for reciprocating motion within the cylinder 22, driven by combustion, and the piston 20 is coupled to the output shaft 24 by a coupling 26 such that said reciprocating motion of the piston 20 drives rotation of the output shaft 24. The engine 18 has increased engine part commonality.

The engine 18 includes a first cylinder bank 28 and a second cylinder bank 30. The first cylinder bank 28 has a first cylinder head 32, the second cylinder bank 30 has a second cylinder head 34, and the first cylinder head 32 and the second cylinder head 34 are formed as common parts such that they are interchangeable. More specifically, the first cylinder head 32 and the second cylinder head 34 are formed as duplicates of the same part - that is, the first cylinder head 32 is identical to the second cylinder head 34 and may, in one example, be formed in the same mould (or other manufacturing equipment) as the second cylinder head 34. In other words, the first cylinder head 32 and the second cylinder head 34 may be formed as common castings such that they are interchangeable parts.

In the example shown, the first cylinder bank 28 has a first cylinder block 36, the second cylinder bank 30 has a second cylinder block 38, the first cylinder block 36 and the second cylinder block 38 being formed as common parts such that they are interchangeable. The first cylinder block 36 is identical to the second cylinder block 38 and may, in one example, be formed in the same mould (or other manufacturing equipment) as the second cylinder block 38. The first cylinder block 36 and second cylinder block 38 may be formed as common castings such that they are interchangeable parts.

One end 40 of the engine 18 is provided with a first mounting part 42 for mounting other components and an opposite end 44 of the engine is provided with a second mounting part 46 for mounting other components. The first mounting part 42 and the second mounting part 46 are formed as common parts such that they are interchangeable. The first mounting part 42 and the second mounting part 46 are arranged with a mounting face 48 for coupling to a transmission, generator or other device.

In one example, the first mounting part 42 and the second mounting part 46 may be arranged to couple a transmission to one end of the engine 18 and an electric motor or generator to the opposite end of the engine 18.

The engine 18 includes the first cylinder bank 28 and the second cylinder bank 30, wherein a drive 50 for a camshaft of the first cylinder bank 28 from the crankshaft is at one end of the crankshaft, and wherein a drive 52 for a camshaft of the second cylinder bank 30 from the crankshaft is at an opposite end of the crankshaft. Advantageously, as the engine 18 is in the form of an opposed cylinder engine wherein the opposed pistons are directly opposed rather than being staggered (as in a traditional "boxer" engine) the engine 18 is shorter and is able to sacrifice having a bit of extra length so as to provide the drive 50, 52 for the camshafts at each end of the engine 18. By having the drive 50, 52 for the camshafts at each end of the engine 18, commonality of parts in the engine 18 is maximised and optimised.

With reference to Figure 8 and Figure 9 of the drawings, arrows 58 show the same head and block unit interfaces facing opposite directions. Figure 9 shows the bottom of the engine 18 depicting common heads and blocks. Note that, in this example, there is an offset profile due to the internal camshaft and balance shaft drive. In alternative examples, there may be no offset.

The coupling 26 from the pistons 20 to the output shaft 24 is arranged such that the pistons 20 have sinusoidal motion for constant rotational velocity of the output shaft 24 when plotted against rotational angle of the output shaft 24. In one particular example, the engine 18 may be in the form of an opposed cylinder engine which may have particular advantages in relation to increasing the commonality of parts, and a particular working interrelationship with the increased commonality of parts, as mentioned above.

The engine 18 may have the same mounting points by way of the mounting faces 48 at the front and rear of the engine 18. It is particularly advantageous to use the present invention with an opposed cylinder engine, as the opposed cylinder engine is shorter owing to directly opposed (rather than staggered) pistons such that it is possible to sacrifice an additional amount of engine length, for example 30mm or so, so as to allow the additional camshaft drive 50, 52 at both ends.

The present invention outlines a design for an engine 18 where the major parts of the engine 18 are common from the first cylinder bank 32 to the second cylinder bank 34 and from the front of the engine 18 to the back of the engine 18. Turning to Figure 10, arrows 60 show identical flywheel mounting faces at the front and rear of the engine 18. Figure 11 shows a common head with timing gear access 62.

With reference to Figures 12 to 21 (Figure 12 includes views a to f), a further example of the invention is shown in which the engine cylinder block is split into two parts, a cylinder block and a crankcase. The applicant has carried the commonality concept forward in such a way that the engine depicted in these drawings comprises the following: two crankcase halves that are common; two cylinder blocks which are common; and two cylinder heads which are common.

The crankcase halves are cast from the same parts, almost fully machined and then the two halves are bolted together and the crankshaft bore is final machined. The machining is the only operation that needs to be conducted with the two halves together; this ensures the two are parts matched and, advantageously, is a simple machining operation, relatively low cost.

More specifically, the example shown in Figures 12 to 21 includes an internal combustion engine 18, including a piston 20, a cylinder 22, and an output shaft 24, wherein the piston 20 is arranged for reciprocating motion within the cylinder 22, driven by combustion, and the piston 20 is coupled to the output shaft 24 by a coupling 26 such that said reciprocating motion of the piston 20 drives rotation of the output shaft 24, wherein the engine 18 includes an engine cylinder block 64 formed as separable parts, being a crankcase 66 and at least one cylinder block 36.

In another aspect, the crankcase 66 is formed of a plurality of separable like parts 68, each of the like parts 68 being cast as a common part. In particular, each of the like parts 68 is an identical part and may be cast from a common mould. In the example shown, the crankcase 66 is formed of a pair of said separable like parts 68, such that each of said separable like parts 68 is a half of the crankcase 66. The engine 18 also includes a pair of cylinder blocks 36, 38, each of the cylinder blocks 36, 38 being formed as a common part.

As depicted, the engine 18 further includes a pair of cylinder heads 32, 34, each of the cylinder heads 32, 34 being formed as a common part. Figure 14 shows CH bolts 72

SUBSTITUTE SHEET (RULE 26) for bolting the cylinder heads 32, 34 to the cylinder blocks 36, 38. The cylinder block 36 may be formed of aluminium 74, held to the crankcase 66 by way of bolts 76 which, by way of non-limiting example, may be MIO studs with 125mm length. Main bearing bolts 78 may be MIO inner hexagon bolts. The crankcase halves 68 (left and right) may be formed from cast iron.

Figure 15 shows the cylinder block 36 having two cylinders and with example dimensions. The bolts 80 relate to a liner and the bolts 82 relate to the head. Figure 16 shows a perspective view of the crankcase half 68 separated from the other like crankcase half 68. Figure 17 shows the aluminium cylinder block 36 (or 38) with a water jacket and two cylinders.

With reference to Figure 18, there is shown a cam arrangement, being a single overhead cam (SOHC) arrangement 84 with a low head height. The arrangement has a pulley 86 in the SOHC layout with a lowered camshaft position. The arrangement is transposed above a double overhead cam (DOHC) arrangement 88 in order to demonstrate the compact nature and comparably low height of the SOHC arrangement 84. Height dimension 90 for the SOHC arrangement 84 is 145mm in the example shown, whereas the height dimension 92 for the DOHC arrangement 88 is 183mm (the double overhead cam DOHC arrangement 92 being shown merely for reference in size). The SOHC arrangement 84 noticeably also provides advantages including being a narrow engine, having common heads, common cylinder blocks and balance shafts which are gear- driven (one front and one rear).

Figures 19 to 21 show a preferred timing drive arrangement with a chain driven system. In particular, Figure 19 shows a front view of the preferred drive arrangement, Figure 20 shows a rear view of the preferred drive arrangement and Figure 21 shows a top view of the preferred drive arrangement. The arrangement has a single overhead camshaft per bank. With particular reference to Figure 19, it is shown diagrammatically that the gear crankshaft 94 drives an oil pump 96, also with a geared arrangement to drive a sprocket mass balance gear 98 which, in turn, drives the single overhead camshaft 100 by way of a chain, the chain being tensioned by a tensioner 102.

Turning to Figure 20, there is shown a rear view of the preferred drive arrangement shown in Figure 19, depicting a drive arrangement for a single overhead camshaft of the opposite cylinder bank. More specifically, the gear crankshaft 94 is in geared arrangement at the other end of the engine 18 to drive another sprocket mass balance gear 104 which, in turn, drives a single overhead camshaft 106 of the opposite cylinder bank by way of a chain, the chain being tensioned by a tensioner 108. Accordingly, with this arrangement, the mass balance shafts are driven by gear engagement with the gear crankshaft 94 at either end of the engine 18. In one example, a silent chain is used for the timing drive, with the sprocket mass balance gear having 19 teeth, and the oil pump 96 being driven by a bush chain. Alternatively, the oil pump 96 may be gear driven directly from the gear crankshaft 94.

Figure 21 shows a top view of the preferred drive arrangement of Figures 19 and 20. This view shows the front drive 110 for driving the single overhead camshaft of one bank of cylinders, and the rear drive 112 for driving the single overhead camshaft of the opposite bank of cylinders. In one example, an oil pump drive may be provided at the front of the engine 18.

The applicant uses a method for forming the engine 18, including the steps of casting the crankcase halves 68 as similar parts; and coupling together the crankcase halves 68 to form the crankcase 66. The step of coupling together the crankcase halves 68 may be performed by bolting together the crankcase halves 68.

The method may further include a step of final machining a crankshaft bore 70 in the crankcase 66 subsequent to the step of coupling together the crankcase halves 68.

This block arrangement as described above may provide the following advantages: part commonality

- freedom of material choice ability to change engine size by changing bores only

- ease of assembly

- ability to change to different liner types in future o spray in liner o piston in base bore material o press in liner o etc

- service/repair cost more common parts with turbo engine The following features in a preferred example of the invention may be particularly advantageous:

- the use of common cylinder head casting for the left and right bank

- the use of a common block-half casting for the left and right bank

- the use of a common mounting faces at the front and rear of the engine

- the ability to mount a transmission, generator or other device to either the front or rear of the engine

- the ability to mount both a transmission to one end of the engine and electric motor/generator to the other end of the engine

- the use of common cam drives

- the use of common balance shafts and drive

These features may result in the following advantages in a preferred example of the invention: less part tooling common castings (the casting metal mould for cylinder block and cylinder head can be reduced by 50%) less machining

- the ability to interchange parts in production and in the field less stock control and variation higher volumes of common parts leading to lower cost more engine flexibility in applications and installations a cleaner engine with fewer external components multiple engine installation and mounting points lower logistics area required for big parts

- simpler production organisation

The advantages in examples of the invention may facilitate a lower cost engine in production, lower stock requirements, lower part costs and lower maintenance costs in the greater part commonality.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

List of features:

10 Previously proposed engine

12 Cylinder head

14 One cylinder bank

16 Opposite cylinder bank

18 Engine in accordance with an example of the present invention

20 Piston

22 Cylinder

24 Output shaft

26 Coupling

28 First cylinder bank

30 Second cylinder bank

32 First cylinder head

34 Second cylinder head

36 First cylinder block

38 Second cylinder block

40 One end of the engine

42 First mounting part

44 Opposite end of the engine

46 Second mounting part

48 Mounting face

50 Drive for a camshaft of the first cylinder bank

52 Drive for a camshaft of the second cylinder bank

54 Filter

56 Sump

58 Arrows

60 Arrows showing identical flywheel mounting faces

62 Timing gear access

64 Engine cylinder block

66 Crankcase

68 Crankcase halves

70 Crankshaft bore

72 CH bolts

74 Aluminium cylinder block

76 Bolts 78 Main bearing bolts

80 Red bolts

82 Black bolts

84 Single Overhead Cam (SOHC) arrangement 86 Pulley

88 Double Overhead Cam (SOHC) arrangement

90 Height dimension for Single Overhead Cam (SOHC) arrangement

92 Height dimension for Double Overhead Cam (DOHC) arrangement

94 Gear crankshaft 96 Oil pump

98 Sprocket mass balance gear

100 Single overhead camshaft

102 Tensioner

104 Sprocket mass balance gear at opposite end of engine 106 Single overhead camshaft of opposite cylinder bank

108 Tensioner at opposite end of engine

110 Front drive

112 Rear drive