CN114607504A - Internal combustion engine with universal parts and common manufacturing method - Google Patents

Abstract

The invention relates to an internal combustion engine with universal parts and a common manufacturing method, which comprises a piston, a cylinder and an output shaft, wherein the piston is arranged in the cylinder to do reciprocating linear motion and is driven by combustion energy, and a coupling mechanism which can realize the reciprocating linear motion of the piston to drive the output shaft to do rotary motion is coupled with the output shaft. The engine may include a first cylinder group having a first cylinder head and a second cylinder group having a second cylinder head, with the first and second cylinder heads being manufactured as interchangeable common parts. The engine may include a crankcase constructed of several separate identical components that are all cast as common components.

Description

Internal combustion engine with universal parts and common manufacturing method

Technical Field

The present invention relates to an internal combustion engine and more particularly, but not exclusively, to an internal combustion engine of the type having a plurality of cylinder banks and which is configured to improve cost effectiveness by using common engine components.

Background

Internal combustion engines provide power sources for vehicles, generators, machinery, and the like. Applicants have discovered that conventional internal combustion engines utilizing crankshafts, crank arms, and connecting rods have limitations and deficiencies with respect to noise, vibration, smoothness, efficiency, and emissions.

The main components that make up conventional engines, particularly V-type, and symmetrical or opposed engines, are not interchangeable with respect to the left and right sides of the engine. For example, the cylinder head on the right bank is different from the left bank and the left bank is different from the right bank. These parts are not only machined into finished products but also have different blanks. This means that different molds, tools and fixtures are used to make, machine and use these parts. Based on this, the corresponding accessories (e.g., the gasket, the mounting surface and the accessory) are also affected by 'non-versatility'. Some manufacturers go to great lengths to make part of the mounting surface of the major component part universal in order to use as many universal components as possible, but still far less than the present invention can achieve.

Applicant aims to provide an internal combustion engine which overcomes or alleviates at least one or more of the disadvantages of the prior art engines whilst providing the engine with a more cost-effective manufacturing advantage.

Accordingly, the illustrated examples of the present invention aim to avoid or at least ameliorate the disadvantages of existing internal combustion engines.

Disclosure of Invention

According to one aspect of the invention, the invented internal combustion engine comprises a piston, a cylinder and an output shaft, wherein the piston is arranged in the cylinder to do reciprocating linear motion and is driven by combustion energy, and a coupling mechanism which can realize the reciprocating linear motion of the piston to drive the output shaft to do rotary motion is coupled with the output shaft.

Preferably, the invented engine comprises a first cylinder group having a first cylinder head and a second cylinder group having a second cylinder head, and the first and second cylinder heads are manufactured as interchangeable common parts.

More preferably, the first and second cylinder heads are manufactured as interchangeable common castings

Preferably, the invented engine comprises a first cylinder group and a second cylinder group, wherein the first cylinder group has a first cylinder block and the second cylinder group has a second cylinder block, and the first and second cylinder blocks are manufactured as interchangeable common parts.

More preferably, the first and second cylinders are manufactured as interchangeable common castings.

Preferably, the inventive engine is provided with a first mounting member on one side for mounting other components and a second mounting member on the other side for mounting the remaining components, wherein the first and second mounting members are manufactured as interchangeable common components.

More preferably, the first and second mounting members are designed to have a mounting surface for attachment to a transmission, engine or other device.

Even more preferably, the first and second mounting members are designed such that one is coupled with the transmission on one side of the engine, and the other is coupled with the motor or generator on the power output side (the other side) of the engine.

Preferably, the inventive engine comprises a first cylinder group and a second cylinder group, wherein the camshaft drive train of the first cylinder group originating from the crankshaft is located on one side of the crankshaft and the camshaft drive train of the second cylinder group originating from the crankshaft is located on the opposite side of the crankshaft.

One form of the coupling mechanism described hereinbefore is designed so that the piston makes a sinusoidal motion relative to the output shaft angle when the output shaft is running at a constant rotational speed. More preferably, the inventive engine is a cylinder mirror symmetry engine.

According to another aspect of the invention, an inventive engine includes a plurality of pistons, a plurality of cylinders, and an output shaft. The engine comprises a first cylinder group and a second cylinder group, wherein a camshaft transmission system of the first cylinder group from the output shaft is positioned on one side of the output shaft, and a camshaft transmission system of the second cylinder group from the output shaft is positioned on the other side opposite to the output shaft.

According to yet another aspect of the present invention, an engine comprises a piston, a cylinder and an output shaft, wherein the piston is disposed in the cylinder for reciprocating linear motion and is driven by combustion energy, and the output shaft is coupled to the piston by a coupling mechanism which enables the reciprocating linear motion of the piston to drive the output shaft to rotate, the engine comprises an engine block which is formed by a plurality of independent components (a crankcase and at least one cylinder block).

According to yet another aspect of the present invention, there is provided an engine comprising a piston, a cylinder and an output shaft, wherein the piston is disposed in the cylinder for reciprocating linear motion and is driven by combustion energy, and wherein the output shaft is coupled to the piston by a coupling mechanism which effects reciprocating linear motion of the piston as hereinbefore described to drive rotational motion of the output shaft, the engine comprising a crankcase formed from a plurality of separate identical parts, each of the separate parts being cast as a common part.

Preferably, these identical components are identical. More preferably, each identical component is cast from a common mold.

One preferred construction of the crankcase is one constructed from a pair of the aforementioned separate identical components, with each separate identical component constituting a crankcase half. More preferably, the inventive engine further comprises a plurality of cylinder banks, and each of the cylinder banks is a common component.

Preferably, the inventive engine further comprises a plurality of cylinder heads, each cylinder head being manufactured as a common component.

According to yet another aspect of the invention, the aforementioned method of manufacturing the invented engine includes the steps of casting the same crankcase half, machining the casting and assembling the crankcase half into a crankcase.

Preferably, the step of assembling the crankcase half-case preferably employs a threaded connection to connect said crankcase half-case.

The engine preferably is manufactured by a method further comprising finishing the crankshaft bore in the crankcase after assembling the crankcase halves.

Drawings

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

FIG. 1 shows a perspective front view of a cylinder mirror symmetric engine using different head and block castings on each cylinder bank;

FIG. 2 shows a perspective rear view of the engine shown in FIG. 1;

3-7 illustrate various views of an example of an inventive internal combustion engine depicting the internal combustion engine example having substantially identical layout in front and rear views;

FIG. 8 shows a perspective view of the engine as shown in FIGS. 3-7 to show the common cylinder head and block;

FIG. 9 shows a bottom view of the internal combustion engine shown in FIGS. 3-8;

FIG. 10 shows perspective views of the engine of FIGS. 3-9 with mounting plates mounted to the front and rear ends of the engine, respectively;

FIG. 11 shows a detailed view of the internal combustion engine cylinder head of FIGS. 3-10 depicting the universal cylinder head and timing gear interface;

12A-12F illustrate different views of a crankcase half-box and a cylinder block of another example engine of the invention;

FIG. 13 shows a partial exploded view of a piston fastening connection in a cylinder of the inventive engine;

FIG. 14 illustrates a cross-sectional view of the proposed threaded connection concept in an example engine;

FIG. 15 shows a top view of the cylinder;

FIG. 16 shows a perspective view of the crankcase half of the engine as shown in FIG. 14;

FIG. 17 shows a perspective view of an aluminum cylinder and its water jacket in the example of the transmitter shown in FIG. 14;

fig. 18 shows a single overhead camshaft cam arrangement having a lower head height than the prior art dual overhead camshaft arrangement;

FIG. 19 shows a front view of a preferred drive train layout in a single camshaft design for each cylinder bank configuration;

FIG. 20 shows a rear view of the drive train arrangement as shown in FIG. 19;

fig. 21 shows a top view of the drive train as shown in fig. 19 and 20.

Detailed Description

As shown in fig. 1 and 2, in many conventional engines, the engine 10 is formed by main components on both left and right sides of the engine 10. In particular, FIG. 1 shows engine 10 with a front view in which a timing belt couples a camshaft of engine 10 and a crankshaft of engine 10, while FIG. 2 shows a rear view of engine 10. These conventional engines 10 have many components that are not interchangeable and can only be used on one side of the engine 10.

In the illustrated example, the engine 10 shown in fig. 1 and 2 is a cylinder mirror symmetry type engine as previously proposed. In the depicted engine 10, the cylinder heads 12 on one bank 14 are different from the cylinder heads on its opposing bank 16, and the engine 10 is also different at one bank 14 and its opposing bank 16. This results in inefficiencies because these parts not only work pieces but also their original castings are different, thereby requiring separate molds, tools and fixtures to manufacture, machine and use the parts. Further, the surrounding parts are also affected by this non-versatility. In particular, components such as shims, mounting faces and accessory parts must be specifically designed and manufactured for each different cylinder group.

The internal combustion engine 18 shown with reference to fig. 3 to 11 is one example of the invention. Advantageously, the internal combustion engine 18 shown in fig. 3-11 improves the versatility of the parts, resulting in fewer parts to machine, common castings, fewer machining, and parts interchange capabilities in production and use. Another advantage is also discussed herein. In particular, fig. 3-7 show various views of the engine 18, the proposed engine arrangement having substantially identical front and rear views (see fig. 3 and 4A). The front and rear ends of the engine 18 can be indicated only from the shape of the oil pan 56 and the position of the filter 54. Fig. 4B shows another rear view of the engine 18, which is similar to fig. 4A, but with the filter 54 shown at a slightly offset viewing angle.

The internal combustion engine 18 of the present invention comprises a piston 20, a cylinder 22 and an output shaft 24, wherein the piston 20 is disposed in the cylinder 22 for reciprocating linear motion, driven by combustion energy, and coupled by a coupling mechanism 26 for realizing the reciprocating linear motion of the piston to drive the output shaft 24 to rotate, and the invented engine 18 has better versatility of engine parts.

The engine 18 includes a first cylinder group 28 and a second cylinder group 30. The first cylinder group 28 has a first cylinder head 32, the second cylinder group 30 has a second cylinder head 34, and the first cylinder head 32 and the second cylinder head 34 are manufactured as interchangeable common parts. More specifically, the first head 32 and the second head 34 are manufactured as duplicate identical components, meaning that the first head 32 and the second head 34 are identical and may be manufactured from the same mold (or other processing equipment). In other words, the first head 32 and the second head 34 are manufactured as interchangeable common castings.

In the illustrated example, the first cylinder group 28 has a first cylinder 36, the second cylinder group 30 has a second cylinder 38, and the second cylinder 36 and the second cylinder 38 are manufactured as interchangeable common parts. The first cylinder 36 is identical to the second cylinder 38 and is manufactured from the same mold (or other processing equipment). The first and second cylinders 36, 38 may be manufactured as interchangeable common castings.

One end 40 of the engine 18 is used to provide a first mounting member 42 for mounting other components and the opposite engine end 44 is used to provide a second mounting member for mounting other components. The first mounting component 42 and the second mounting component 46 are manufactured as interchangeable, common parts. The first mounting member 42 and the second mounting member 46 provide a mounting surface 48 for attachment to a transmission, generator or other device.

In one example, the first mounting member 42 and the second mounting member 46 may be configured to be coupled to a transmission at one end of the engine 18 and to a motor or generator at an opposite end of the engine 18.

The engine 18 includes a first cylinder bank 28 and a second cylinder bank 30, with a camshaft drive train 50 from the first cylinder bank 28 of the crankshaft disposed at one end of the crankshaft and a camshaft drive train 52 from the second cylinder bank 30 of the crankshaft disposed at the opposite end of the crankshaft. Advantageously, because engine 18 is a cylinder mirror symmetric engine in which opposed cylinders are directly mirror opposed rather than staggered (as in a conventional 'opposed' engine), engine 18 is shorter with only a slight sacrifice in width and camshaft drivetrains 50 and 52 are located at each end of engine 18. Since the camshaft drive trains 50 and 52 are split at each end of the engine 18, the component versatility of the engine 18 is maximized and optimized.

Referring to fig. 8 and 9, arrows 58 indicate the same cylinder head and cylinder block interface facing each other. FIG. 9 shows a bottom view of engine 18 depicting a common cylinder head and block. Note that in this example, an offset profile is caused due to the internal camshaft and balance shaft drive train. Other examples may not have this offset.

The coupling mechanism 26 of the piston 20 and the output shaft 24 is arranged such that the piston 20 makes a sinusoidal movement relative to the output shaft rotation angle when the output shaft is running at a constant rotational speed. In a particular example, the engine 18 is a cylinder mirror engine and has particular advantages in terms of increased component versatility and its particular interaction as previously described.

The engine 18 may have identical mounting points on the mounting faces 48 of the front and rear engine faces. The use of the cylinder mirror engine of the present invention is particularly advantageous because the direct opposition of the pistons makes the cylinder opposed engine shorter, so that camshaft drive trains 50 and 52 can be installed at both ends of the engine at the expense of only some engine width, e.g., about 30 mm.

The present invention outlines a design in which the main components of the engine 18 are generalized, as the first cylinder group 32 and the second cylinder group 34 may be generalized, and the front end and the rear end of the engine 18 may be generalized.

The arrow 60 in fig. 10 shows the identical flywheel mounting faces at the front and rear of the engine. Fig. 11 shows a generic cylinder head fitted with a timing gear interface 62.

Fig. 12A-21 further illustrate an example of the invention in which the engine block is divided into two halves, a block and a crankcase. The generalised concept proposed by the applicant enables the engine described in the figures to have the following characteristics:

-two crankcase halves that are common;

-two cylinders which are universal, and;

two heads that can be used universally.

The half boxes of the crankcase are from the same casting, after the machining is basically finished, the two half boxes are connected together through a stud, and finally, the crankshaft shaft hole is machined. The two half-boxes need only be machined so that the two parts cooperate with each other, with the advantage of a simple machining operation and relatively low costs.

More specifically, the example illustrated internal combustion engine 18 of fig. 12A-21 includes a piston 20, a cylinder 22, and an output shaft 24, wherein the piston 20 is disposed in the cylinder 22 for reciprocating motion, is driven by combustion energy, and is coupled to the output shaft 24 by a coupling mechanism that enables the aforementioned reciprocating linear motion of the piston to drive the output shaft for rotational motion, and the engine 18 includes an engine block 64 that is comprised of a separate crankcase 66 and at least one block 36.

The crankcase 66, on the other hand, is made up of a collection of individual identical components 68, each individual identical component 68 being a common casting. In particular, each individual identical part 68 is identical and may be cast from a common mold. The crankcase 66 in the example consists of said separate identical part 68, so that said separate identical part 68 is a half-case of the crankcase 66. The engine 18 also includes a pair of blocks 36 and 38, and is a common component.

The depicted engine 18 further includes a pair of cylinder heads (32 and 34), and is a common component. Fig. 14 shows a head bolt 72 for connecting the head (32 and 34) and the block (36 and 38) by threads. The cylinder block 36 may be an aluminum piece 74 secured to the crankcase 66 by bolts 76, which may be, without limitation, 125mm long M10 studs. The main bearing bolts 78 may be M10 socket head cap bolts. The crankcase halves 68 (left and right) may be cast iron.

Fig. 15 shows a block 36 having two cylinders and exemplary dimensions thereof. Bolts 80 connect the liner and bolts 82 connect the head. Fig. 16 shows an overall view of a separate crankcase half-case 68 (the other half-case is identical). Fig. 17 shows an aluminum block 36 (or 38) having one water jacket and two cylinders.

Fig. 18 shows the cam arrangement in a single overhead cam arrangement 84 with a low head height. In this arrangement there is one pulley 86 in a single overhead cam arrangement and the camshaft position is lowered. This arrangement is translated from the dual overhead cam arrangement 88 to show the compact nature and relatively low height of the single overhead cam arrangement 84. The height 90 of the example single overhead cam arrangement 84 is 145mm while the height 92 of the dual overhead cam arrangement is 183mm (the dual overhead cam arrangement 92 is for dimensional reference only). Significant advantages of the single overhead cam arrangement 84 include a narrow engine with a common cylinder head, common cylinder block, and geared balance shafts (one at the front end of the engine and one at the rear end).

Fig. 19-21 show a preferred timing drive system arrangement with a chain drive system. In particular, fig. 19 shows a front view, fig. 20 shows a rear view, and fig. 21 shows a top view of a preferred timing drive system arrangement. In this arrangement there is a single overhead camshaft for each bank. In particular, fig. 19 diagrammatically shows a gear train arrangement of a gear crankshaft drive train 94 and an oil pump 96, as well as a driving sprocket mass balance gear 98 which in turn drives a single overhead camshaft 100 via a chain which is tensioned by a tensioning wheel 102.

FIG. 20 shows a rear view of the preferred drive train arrangement of FIG. 19 depicting a single overhead camshaft drive train arrangement on the opposed cylinder banks. More specifically, the gear crankshaft 94 in the gear train arrangement at the other end of the engine 18 drives another sprocket mass balance gear 104 which in turn drives a single overhead camshaft 106 of the opposed cylinder bank via a chain that is tensioned by a tensioner 108. Accordingly, according to this arrangement, the mass balance shafts at each end of the engine 18 are driven in mesh by gears having geared crankshafts 94. In one example, a silent chain is used to drive the timing drive train, the sprocket mass balance gear has 19 teeth, and the oil pump 96 is driven by a chain sleeve. Alternatively, oil pump 96 may be directly driven by a gear train from crankshaft gear 94.

Fig. 21 shows a top view of the preferred drive train arrangement shown in fig. 19 and 20. This view shows a front drive train 110 driving a single overhead camshaft on one cylinder bank and a rear drive train 112 driving a single overhead camshaft on the opposite cylinder bank. In one example, an oil pump drive train 114 may be disposed at a forward end of the engine 18.

Applicants manufactured engine 18 using a method that included the steps of casting identical crankcase halves 68, and assembling crankcase halves 68 into one crankcase 66. The step of assembling the crankcase half-case 68 may use bolts to attach the crankcase half-case 68.

The method of manufacture further includes finishing the crankshaft bore 70 in the crankcase after assembling the crankcase half-case 68.

This aforementioned cylinder arrangement may bring the following advantages:

commonality of parts

Freedom of material selection

-varying the engine displacement by varying only the aperture

Easy assembly

Post-alteration of different types of liners

oil mist spray in cylinder hole

o-piston based hole material

o press-fitting into cylinder hole

o and so on

Low maintenance/repair costs

More common components on turbocharged engines

The following features of a preferred embodiment of the invention may provide unique advantages:

use of common cylinder head castings for left and right cylinder banks

Use of common cast half-cylinders for left and right banks

Common mounting surfaces for front and rear ends of the engine

The ability to mount a gearbox, generator or other device at one of the front and rear ends of the engine

The ability to install a gearbox at one end of the engine and a motor/generator at the other end of the engine at the same time

Ability to use a universal cam drive train

Ability to use universal balance shafts and their drive trains

These features of the preferred embodiment of the invention may bring the following advantages:

less machining of parts

General casting (50% reduction of cylinder and head metal casting molds)

Less machining

Ability to interchange parts during manufacture and use

Less inventory control and fluctuation

Lower costs due to higher general component batches

Greater engine application and installation flexibility

A more compact engine with fewer external components

Multiple engine mounting and assembly points

Less logistics space requirement for large components

More concise production organization

Advantages of the present example may include lower engine manufacturing costs, lower inventory requirements, lower part costs, lower maintenance costs, and higher part versatility.

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 limitation. It will be apparent to persons 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. The present invention should not be limited to any of the illustrative schemes described above.

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

List of features and reference numerals of the drawings

10 earlier proposed engine

12 cylinder cover

14 cylinder groups

16 opposed cylinder banks

18 corresponding example Engine of the invention

20 piston

22 cylinder

24 output shaft

26 are coupled

28 first gas group

30 second cylinder group

32 first cylinder cover

34 second cylinder cover

36 first cylinder

38 second cylinder

40 one side of the engine

42 first mounting part

44 opposite side of the engine

46 second mounting part

48 mounting surface

50 camshaft drive train of first cylinder group

52 camshaft drive train for second cylinder bank

54 filter

56 oil pan

58 arrow

60 arrow indicating the same flywheel mounting surface

62 timing gear interface

64 Engine block

66 crankcase

68 crankcase half-case

70 crankcase shaft hole

72 cylinder head bolt

74 aluminum cylinder

76 bolt

78 main bearing bolt

80 red bolt

82 black bolt

84 Single overhead cam arrangement

86 pulley

88 dual overhead cam arrangement

90 single overhead cam placement height

92 double overhead cam deployment height

94 gear crankshaft

96 oil pump

98 chain transmission mass balance gear

100 single overhead camshaft

102 tension roller

104 opposite side chain drive mass balance gear of engine

106 single overhead camshaft with opposed cylinder banks

108 opposite side tension wheel of engine

110 front drive train

112 rear drive train

Claims (27)

1. An internal combustion engine characterized by: the engine comprises a piston, a cylinder and an output shaft, wherein the piston is arranged in the cylinder to do reciprocating linear motion and is driven by combustion energy, and a coupling mechanism which can realize that the reciprocating linear motion of the piston drives the output shaft to rotate is coupled with the output shaft.

2. The internal combustion engine of claim 1, wherein: comprising a first cylinder group comprising a first cylinder head and a second cylinder group comprising a second cylinder head, and the first and second cylinder heads are manufactured as interchangeable common parts.

3. The internal combustion engine of claim 2, wherein: the first and second cylinder heads are manufactured as interchangeable common castings.

4. The internal combustion engine of claim 1, wherein: comprising a first and a second cylinder group, wherein the first cylinder group comprises a first cylinder block and the second cylinder group comprises a second cylinder block, and the first and second cylinder blocks are manufactured as interchangeable common components.

5. The internal combustion engine of claim 4, wherein: the first and second cylinders are manufactured as interchangeable common castings.

6. The internal combustion engine of claim 1, wherein: the first mounting part on one side of the inventive engine is used for mounting other components, the second mounting part on the other side of the engine is used for mounting other components, and the first and second mounting parts are manufactured as interchangeable common components.

7. The internal combustion engine of claim 6, wherein: the first and second mounting members are configured to have a mounting surface for connection to a transmission, generator or other device.

8. The internal combustion engine of claim 7, wherein: the first and second mounting portions are configured to be coupled to the transmission on one side of the engine and to one of the electric machines or generators on an opposite side of the engine.

9. The internal combustion engine according to claims 1 to 8, characterized in that: the invented generator includes a first bank of cylinders and a second bank of cylinders, wherein the camshaft drive train of the first bank of cylinders from the crankshaft is located at one end of the crankshaft and the camshaft drive train of the second bank of cylinders from the crankshaft is located at the opposite end of the crankshaft.

10. The internal combustion engine according to claims 1 to 9, characterized in that: the coupling mechanism is arranged such that the piston makes a sinusoidal motion relative to the output shaft angle when the output shaft is rotating at a constant speed.

11. The engine of claim 10, wherein: the engine is a cylinder mirror symmetry engine.

12. An internal combustion engine characterized by: the engine comprises a first cylinder group and a second cylinder group, wherein the camshaft transmission system of the first cylinder group from the output shaft is positioned at one end of the output shaft, and the camshaft transmission system of the second cylinder group from the output shaft is positioned at the other opposite end on the output shaft.

13. The engine of claim 12, wherein the first cylinder bank has a first cylinder head and the second cylinder bank has a second cylinder head, and wherein the first and second cylinder heads are manufactured as interchangeable common parts.

14. An engine as defined in claims 12 and 13 wherein: the first cylinder group has a first cylinder and the second cylinder group has a second cylinder, the first and second cylinders being manufactured as interchangeable common parts.

15. The engine of claims 12-14, characterized in that: the engine is a cylinder mirror symmetry type engine.

16. An internal combustion engine characterized by: comprising a piston, a cylinder and an output shaft, wherein the piston is arranged in the cylinder to perform reciprocating linear motion and is driven by combustion energy, and the piston is coupled with the output shaft by a coupling mechanism which can realize the reciprocating linear motion of the piston and drive the output shaft to rotate.

17. An internal combustion engine characterized by: the engine comprises a plurality of pistons, a plurality of cylinders and an output shaft, wherein the pistons are arranged in the cylinders to do reciprocating linear motion and driven by combustion energy, and a coupling mechanism which can realize the reciprocating linear motion of the pistons to drive the output shaft to rotate is coupled with the output shaft.

18. The engine of claim 17, wherein: each of the identical components is identical.

19. The engine of claim 18, wherein: each of said identical parts is cast from a common mould.

20. The engine of claims 17-19, characterized in that: the crankcase is formed of a pair of said separable identical components, so that each of said separable identical components is one half of the crankcase.

21. The engine of claim 20, wherein: the engine further includes a plurality of cylinders, and each cylinder is manufactured as a common component.

22. An engine as claimed in claims 20 and 21 wherein: the engine further includes a plurality of cylinder heads, and each cylinder head is manufactured as a common component.

23. The engine manufacturing method according to any one of claims 20 to 22, characterized in that: the method includes the steps of casting the same crankcase half-case, and joining the crankcase half-case to the entire crankcase.

24. The engine manufacturing method according to claim 23, characterized in that: the step of connecting the crankcase halves is connecting the crankcase halves by threads.

25. A method of manufacturing an engine as set forth in claim 23 or 24, wherein: further comprises the step of finally processing the crankshaft shaft hole after the crankcase is connected with the crankcase half box.

26. An internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.

27. A method of manufacturing an engine, as discussed in detail hereinbefore, with reference to the accompanying drawings.

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