GB2140502A - An engine including fibre reinforced plastics - Google Patents

Abstract

An engine 80 has an engine block and crankcase formed from fibre reinforced plastics material of modular construction. A series of fibre reinforced frame members 88 are secured to bearers 92 for crankshaft bearings 94 by skeins of carbon fibres 98 wound around the frame members 88 and the bearers 92. Panels 120, 124, 128 on the outside of the frame members 88 and of the bearers 92 contain a coolant and a liquid lubricant within the engine 80. A metal top plate 84 from which metal cylinder liners 86 depend is secured to the tops of the frame members 88. Various engine components of fibre reinforced plastics are mentioned, glass or carbon fibres being preferred. <IMAGE>

Description

SPECIFICATION An engine This invention relates to engines and more particularly, but not exclusively, to internal combustion engines.

According to the present invention, there is provided an engine having an engine block comprising fibre reinforced plastics material.

A crankcase of the engine and an oil sump of the engine may be of integral construction and comprise fibre reinforced plastics material. Alternatively, the crankcase may be integral with the engine block and comprise fibre reinforced plastics material.

In the preferred form of the engine, the engine block and the crankcase comprise, a plurality of fibre reinforced plastics frame members each secured at one end to a respective fibre reinforced plastics crankshaft bearing support member, a respective skein of resin bonded fibres wound around each said frame member and corresponding bearing support member so as to secure the frame member and the bearing support member together, and panel members locatable about the outer surfaces of the frame members and the bearing support members so asto contain a coolant and a liquid lubricant within the engine.

Desirably, each frame member at the lower end thereof defines a concave cylindrical surface which engages a portion defining a cylindrical surface of the respective bearing support member, and the skein of carbon fibres is wound longitudinally along the frame member and around the portion of the bearing support member.

A cylinder head portion of the engine might comprise fibre reinforced plastics material, and metal cylinder liners within which piston members are locatable may depend from the cylinder head portion being integral therewith, each said cylinder having an upper closure portion thereof.

The invention will now be further described byway of example only with reference to the accompanying drawings, in which: Figures 1 to 3 show transverse sectional representations of alternative constructions of internal combustion engines; Figure 4 shows a perspective, partly cut-away view of part of another internal combustion engine, and Figures 5 and 6 show to an enlarged scale portions of the engine of Figure 4.

Referring now to Figure 1, part of an engine 10 is shown and comprises a conventional metal cylinder head 12 (the tappets, rocker cover etc. being omitted for clarity) secured by screws 14 to a fibre reinforced plastics engine block 18. A metal crankcase 20 is secured by bolts 22 to a flange 24 of the engine block 18, and a metal, oil retaining sump 23 is clamped by bolts 25 to a flange 26 of the crankcase 20. Split mountings 32 (only one is shown) for a crankshaft 33 are held in the crankcase 20 by screws 34 extending through the crankcase 20, and support bearings (not shown) for the crankshaft 33. A connecting rod 36 mounted on the crankshaft 33 extends into a metal cylinder liner 38 where it is pivotally connected to a metal piston 40.A flange 42 at the upper end of the liner 38 is supported by a recessed flange 44 of the engine block 18, whilst at the lower end of the liner 38 a metal sealing ring 46 locates between the liner 38 and the engine block 18. The liner 38 is held against the recessed flange 44 by the cylinder head 12, a proprietory seal and sealing compound (not shown) being applied between the liner 38 and the recessed flange 44, and in similar joints in the engine 10. The liner 38 and the engine block 18 define therebetween a space 48 for the circulation of a cooling medium 50 such as water, and spaces (not shown) for the return of lubricating oil from the cylinder head 12 to the sump 24.

The engine 10 operates in a conventional manner, but because of the use of the fibre reinforced plastics engine block 18, a saving in weight has been made in comparison with an engine having a conventional cast iron block.

In Figure 2, a modified engine 54 is shown similar in many respects to the engine 10 of Figure 1.

However, a combined crankcase and sump is provided by a fibre reinforced plastics trough 56 having a flange 58 secured by bolts 22 to the flange 24. A crankshaft 33 is supported by bearings (not shown) in split mountings 60 secured by screws 62 to the underside of the engine block 18.

The engine 54 operates in a conventional manner, but is lighter than the engine 10 of Figure 1 because of the greater use made of the fibre reinforced plastics material.

An even more lightweight engine is shown in Figure 3, and comprises a modified engine 64 similar to the engine 10 of Figure 1, but in which a fibre reinforced engine block 66 has a skirt 68 which replaces the crankcase 20 of Figure 1, and a sump 70 also of fibre reinforced plastics material is attached to a flange 74 of the skirt 68 by bolts 72. In all other respects the engine 64 is identical to the engine 10 of Figure 1.

A modular approach to the use of fibre reinforced plastics material in an engine is shown in Figure 4, in which an engine 80 comprises a fibre reinforced plastics modular frame 82 and a steel top plate 84 from which cylinder liners 86 depend. The frame 82 at each side, comprises five (only four are shown) frame members 88 each seated at an arcuate lower end 89 thereof on a cylindrical spigot 90 from a split bearer 92 in which a crankshaft bearing 94 (only one is shown) is mounted to support a crankshaft 96, the frame member 88 having an inclined face 91 which bears against a correspondingly inclined end 93 of the bearer 92.A skein of resin impregnated carbon fibres 98 is wound longitudinally by a filament winding technique along each frame member 88 through a grove 102 (see Figure 5) at the upper end of the frame member 88, and around the spigot 90 (see Figure 6), to bind the frame member 88 firmly to the respective bearer 92 when the resin is cured. The top plate 84 rests on a ceramic spacer 104 on the upper end of the frame member 88, and is clamped thereto by screws 106 in a fibre reinforced plastics locking bar 108 which bears against a shoulder 110 of the frame member 88 and against an arcuate faced flange 112 of the top plate 84.A fibre reinforced plastics bottom plate 116 at the lower end of the cylinder liners 86 is shaped to fit about and is bonded to the frame members 88, and has respective cylindrical holes 118 in which the cylinder liners 86 locate, a layer (not shown) of a ceramic material on each cylinder liner 86 providing a thermal insulating barrier. Fibre reinforced plastics side panels 120 (only one is shown) are secured to the bearers 92 and top plate 84 by screws 122, whilst a fibre reinforced plastics sump panel 124 is secured by screws 126 (not shown) to the underside of the bearers 92, the ends of the engine 80 being closed by fibre reinforced end panels 128 (only one is shown) secured by screws 130 to the top plate 84 and to the sump panel 124.A conventional cylinder head (not shown) is clamped in a conventional mannertothe top plate 84, and a connecting rod (not shown) is linked at one end to a piston member (not shown) in the liner 86 and at the other end to the crankshaft 96.

Other usual components of an engine, such as an oil pump and a coolant pump are fitted in a conventional manner, necessary adaptions being made to take account of the plastics material used for much of the engine 80.

In operation, the engine 80 performs as a conventional internal combustion engine, but is comparatively lightweight as a result of the widespread use of fibre reinforced plastics material in the construc tion. The ass of the frame members 88 provides a basic moduleywhich a required engine length can be obtained.

Additional components of the aforedescribed engines might be of fibre reinforced plastics material for example, the piston members, connecting rods, gudgeon pins, oil pump coolant pump, valves, valve springs, etc. Furthermore, the cylinder head might be constructed from fibre reinforced plastics material, with the cylinder liners having an upper closure portion in which inlet and exhaust ports are defined, for example being of inverted egg cup form. The top plate 84 might comprise fibre reinforced plastics material and might be integral with the cylinder head. Where appropriate cross-bracing members comprising fibre reinforced plastics material may be fitted to resist twisting loads on the engine.

It will be understood that when metal components have to locate in the fibre reinforced plastics material of the engines 10,80, appropriate metal threaded inserts or bushes may be moulded in situ in the plastics material. Conventional sealing gaskets have been omitted from the description of the engines, but their use and that of other conventional features of an internal combustion engine may be inferred.

For most applications, glass fibres may be used as the reinforcing elements in conventioanal press moulded sheet, or sheet moulding compounds, but for more heavily loaded components, particularly those subjected to fatigue loading, the use of carbon fibres is preferred. Injection moulding using short carbon, aramid, or glass fibres, might also be used in the manufacture of components of the engine. In some of the more lightly loaded components, parti cularlythose subjected to very low tensile stresses, conventional granular fillers may be used. The fibre or filled plastics material must be selected so as to be compatible with the particular duty to be performed, and may need to be oil tolerant and to match the thermal expansion characteristics of adjacent components.

In order to improve the rigidity of the engine of Figure 4, the upper portion of each frame member 88 may be extended to buttress an adjacent cylinder liner 86, an appropriate layer of a thermal insulating material being interposed between the frame member 88 and the respective cylinder liner 86. Some modification of the shape of the plastics components ofthe engine might necessary for vibration damping, to reduce the vibration propagation and sound emission properties of the components.

As an alternative to the use of the skeins 98, a continuous filament might be used extending from one frame member 88 to another, for example to an adjacent frame member 88 or to a frame member 88 at the other side of the engine.

Claims (1)

1. A heat engine having an engine block comprising fibre reinforced plastics material.

2. An engine as claimed in Claim 1,wherein a crankcase and an oil sump of the engine are of integral construction and comprise fibre reinforced plastics material.

3. An engine as claimed in Claim 1, wherein a crankcase of the engine is integral with the engine block and comprises fibre reinforced plastics material.

4. An engine as claimed in Claim 3, wherein an oil sump of the engine is of fibre reinforced plastics material.

5. An engine as claimed in Claim 1, wherein the engine block and a crankcase portion comprise a plurality of fibre reinforced plastics frame members each secured at one end to a respective fibre reinforced plastics crankshaft bearing support member, a respective skein of resin bonded fibres wound around each said frame member and corresponding bearing support member so as to secure the frame member and the bearing support member together, and panel members locatable about the outer surfaces of the frame members and the bearing support members so as to contain a coolant and a liquid lubricant within the engine.

6. An engine as claimed in Claim 5, wherein the panel members comprise fibre reinforced plastics material.

7. An engine as claimed in Claim 5 or Claim 6, wherein each frame member at the lower end thereof defines a concave cylindrical surface which engages a portion defining a cylindrical surface of the respective bearing support member, and the skein of carbon fibres is wound longitudinally along the frame member and around the portion of the bearing support member.

8. An engine as claimed in any one of the preceding Claims, wherein a top plate member is adapted to be supported by the engine block, and metal cylinder liners within which piston members are locatable depend from the plate member.

9. An engine as claimed in Claim 8, wherein the top plate member comprises fibre reinforced plastics material, and thermal insulating material is disposed between the liners and the top plate member.

10. An engine as claimed in any one of Claims 1 to 7, wherein a cylinder head portion of the engine comprises fibre reinforced plastics material.

11. An engine as claimed in Claim 10, wherein metal cylinder liners within which piston members are locatable depend from the cylinder head portion being integral therewith, each said liner having an upper closure portion thereof.

12. A heat engine substantially as hereinbefore described with reference to Figure 1, or Figure 2, or Figure 3, or Figures 4 to 6 of the accompanying drawings.

New claims or amendments to claims filed on 14 May1984 Superseded claims 1 New or amended claims:

1. A heat engine having an engine block comprising a cylinder liner of sufficient strength to resist bursting, and an outer member of fibre reinforced plastic material which locates the cylinder liner and which is spaced apart from the liner along a portion of its length.