GB2425570A

GB2425570A - I.c. engine with cylinder head, cylinder block and manifold formed integrally

Info

Publication number: GB2425570A
Application number: GB0508594A
Authority: GB
Inventors: James William Griffith Turner
Original assignee: Lotus Cars Ltd
Current assignee: Lotus Cars Ltd
Priority date: 2005-04-27
Filing date: 2005-04-27
Publication date: 2006-11-01
Anticipated expiration: 2025-04-27
Also published as: GB0508594D0; GB2425570B

Abstract

The monoblock i.c. engine has a single component 10 comprising a cylinder head portion 203, a cylinder block portion 202 and a manifold portion 204. The manifold portion may be an exhaust manifold. Inlet runners (23,24,25, fig.1) may also be integral with the component 10. The engine has a number of poppet valves 14,16 which extend through passages provided in the cylinder head portion 203 and which are engageable with valve seats that span both a surface of the cylinder head portion 203 and of the cylinder block portion 202. The valves 14,16 can thus be larger, improving performance and/or packaging of close-spaced fuel injectors and facilitating spray-guided direct injection technology. A gasoline direct fuel injector 400 may be provided in a region where the cylinder head portion 203 meets the cylinder block portion 202. A crankcase 214, eg of magnesium, may be attached to the unitary component 10 by mechanical fasteners 310, 311. The whole assembly may have a metal-matrix composite (MMC) insert for strength. The engine may be of Vee-configuration. with two head/block/manifold units attached to a common crankcase.

Description

AN INTERNAL COMBUSTION ENGINE

The present invention relates to an internal combustion engine with a novel arrangement of cylinder head, cylinder S block and crankcase.

Currently, the conventional architecture of a four- stroke poppet valve internal combustion engine is a combination of an integrated crankcase and cylinder block (formed as one unit) and a separately formed cylinder head, the cylinder head being bolted to the top of the cylinder block with a high-pressure cylinder head gasket sealing the junction between the cylinder head and the cylinder block. A separately formed exhaust manifold is bolted to the cylinder head, to collect combusted gases expelled from the cylinders and to relay them to e.g. a turbocharger turbine or directly to an exhaust system (exhaust pipe and catalyst combination) The present invention in a first aspect provides an internal combustion engine having a cylinder head and a cylinder block integrally formed as portions of a single first component characterised in that the first component also has a manifold portion formed as an integral part thereof.

The present invention in a second aspect provides an internal combustion engine assembly comprising a first component which has both a cylinder head portion and a cylinder block portion integrally formed therein and a crankcase attached to the first component by mechanical fastening means characterised in that the first component also has a manifold portion formed as an integral part thereof.

The present invention provides in a third aspect a Vee configuration internal combustion engine comprising first and second components each of which has a cylinder head portion and a cylinder block portion integrally formed therein and both of which are connected to a common independently formed crankcase by mechanical fastening means characterised in that each of the first and second components also has a manifold portion formed as an integral part thereof.

The present invention provides in a fourth aspect a method of fabrication of an internal combustion engine comprising: forming a single component with a cylinder head portion which provides a cylinder head of the engine and which is integrated with a cylinder block portion which provides a cylinder block of the engine, whereby the engine is provided with the cylinder head and the cylinder block without a need for mechanised fasteners securing the cylinder head to the cylinder block; and integrating in the said single component during forming thereof a manifold portion.

The present invention provides in a fifth aspect a method of fabricating a Vee engine comprising forming a pair of components each with a cylinder head portion which provides a cylinder head of the engine and which is integrated with an integral cylinder block portion, an integral cylinder block portion and an integral manifold portion, the cylinder portions of the pair of components each being secured by bolts to a common separately formed crankcase with the bolts attaching the cylinder block portions to the crankcase each extending at an angle to the bearing surface panels of the crankcase and also the bolts attaching one cylinder block portion to the crankcase extending at an angle to the bolts attaching the other cylinder block portion to the crankcase, whereby the engine is provided with cylinder heads and cylinder blocks without the need for mechanical fasteners to secure the cylinder heads to the cylinder blocks and the arrangement of bolts connecting the cylinder bock portions to the crankcase provides a triangulation of forces.

The new engine architecture provided by the present invention allows several of the components conventionally separately formed to be eliminated since they are replaced by features of the engine structure itself. This reduces the bill-of-material costs for the engine construction and reduces build time. It also provides several other advantages, discussed below.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an integrated cylinder block and cylinder head according to the present invention; Figure 2 is a cross-sectional view of the integrated cylinder block and cylinder head of Figure 1 showing an integrated exhaust manifold; Figure 3 is a perspective view of the integrated cylinder block and cylinder head of Figure 1, with the integrated cylinder block and cylinder head inverted in comparison with the Figure 1 view; Figure 4 is a view of an interior of one of the cylinders in the integrated cylinder block and cylinder head of the Figures 1 to 3; and Figure 5 shows a detail view of a variant of the previously illustrated engine.

In Figure 1 there can be seen an engine component 10 which by virtue of integrated features of shape and configuration functions as a cylinder head, cylinder block and exhaust manifold (thereby replacing the separate components of a conventional engine and removing the need for gaskets required in such a conventional engine) The engine component 10 has defined therein three cylinders 11, 12 13 (see Figure 3) each open at one end.

The component 10 defines not only the circular cross-section bores of the cylinders 11, 12, 13 (in which slide pistons), but also the cylinder head surfaces of the cylinders 11, 12, 13. This can be seen in Figure 4 where the interior of cylinder 12 is shown. The cylinder head surface of the cylinder 12 is of "pentroof" configuration or domed in nature and is provided with valve seats for two inlet valves 14, 15 and two exhaust valves 16, 17. Also an aperture 18 is provided either for a spark plug (in the case of a gasoline engine) or an injector (in the case of a diesel engine) . The inlet valves 14, 15 and the exhaust valves 16, 17 are all poppet valves and the stems of these valves can be seen in Figure 1, as can the valve springs 19, 20, 21, 22 provided for the valves.

In Figure 1 it can be seen that inlet runners 23, 24, 25 are formed in the component 10. Four bolts, e.g. 26, 27, 28, 29 are provided around the entrance of each inlet runner to allow a manifold to be bolted to the component 10.

In Figure 2 it can be seen that the single component 210 has integrated in it a cylinder block portion 202, a cylinder head portion 203 and an exhaust manifold 204 connected at a junction 205 to an exhaust system 206.

Coolant passages 207, 208, 209 allow coolant to cool the cylinder block piston, the cylinder head portion and the exhaust manifold portion. The inlet poppet valve 10 extends through a suitable passage in the cylinder head portion 203, as does the exhaust poppet valve 16. The component 201 is cast in an alloy of aluminium. A cylinder liner 212 has an externally threaded portion which engages a threaded portion 213 of the component 201. The cylinder liner 212 extends below the component 201 into a crankcase 214.

The crankcase 214 is a vertically split crankcase. The crankcase is made of aluminium alloy and houses a crankshaft 215. A separate oil pan 217 is used since having a vertical split oil pan could give leakage problems.

In Figure 3 it can be seen that coolant manifold is also integrated in the component 10; three ports 36, 37, 38 for coolant flow are shown surrounded by a wall 39 which defines a sealing surface 40 to which other parts of the cooling system can be joined with an intervening gasket. The coolant passages 207, 208, 209 defined in the component 10 allow coolant to flow around the cylinders 11, 12, 13 in the cylinder block portion 202 of the component and also around the cylinder head 203 and the exhaust manifold 204.

In Figure 3 it can also be seen that the liners (e.g. 212) of the cylinders 11, 12, 13 have lowermost portions which extend below a planar base surface 41 of the cylinder block portion 202 of the component 10. Threaded bolt holes, e.g. 42, 43, 44, 45, 46 are provided in the planar base surface 41 to enable the crankcase 214 to be bolted to the component 10, with a sealing gasket 300 interposed between the crankcase and the planar base surface 41.

From the above it will be understood that the engine architecture described eliminates the need for a cylinder head gasket, cylinder head studs and many components associated with e.g. the exhaust manifold. This reduces bill-of-material costs and build time and by eliminating components improves reliability. Also, the integration of the exhaust manifold in the single component allows it to be cooled by coolant running through the integrated block/head/manifold and this allows the coolant to be heated to working temperature quickly and also facilitates, in an engine with a turbo-charger, a cooler temperature of exhaust gases flowing into the turbine inlet.

Since no high torque fasteners are required to fasten a cylinder head to a cylinder block there are no material stresses/strain in the region surrounding the tops of the cylinders. This reduces bore distortion of the cylinders and so reduces oil consumption and friction (because the piston rings have less tangential loading due to the removal of a requirement to confirm with an out-of-round bore cross- section during piston reciprocation) The integration of the exhaust manifold with the cylinder block and head allows the exhaust outlet flange of the manifold to be closer to the cylinders than is the case with a conventional (separate component) exhaust manifold, where the design must accommodate apertures for fasteners.

This has the benefit of reducing pre-catalyst volume and hence improving catalyst warm-up and light-off. Also in a turbo-charged engine the reduced pre-turbine volume improves throttle response. The improved packaging also can be of benefit for crash protection and the integrated design with coolant flowing throughout reduces thermal distortion.

Direct fuel injectors are frequently (though not exclusively) placed underneath intake ports. In a conventional engine the cylinder head design must include sufficient metal to accommodate the injectors in the vicinity of the cylinder head/block interface, with the injectors raised above the interface, necessitating a raising of the intake port position and restricting choice on the inlet port size and shape. By eliminating the use of a cylinder head gasket the present invention provides an engine in which the direct injectors can be provided in a location normally split in two by the cylinder head gasket; this can be seen in Figure 2 where a gasoline direct injector 400 is shown.

The new engine design also permits use of larger poppet valves, because the valve seat machining can span not only the (typically pentroof or domed) cylinder head parts of the cylinder, but also the cylindrical bore parts of the cylinders as well. This can be done with reduced concerns about cylinder liner stability under a separate cylinder head. The use of larger valves will benefit performance and/or packaging of close-spaced fuel injectors in the combustion chamber, important to facilitate the use of new "spray-guided" direct injection technology.

The whole assembly can also easily accept a metal matrix composite (MMc) insert for strength; this could be a one-piece component which would support both the cylinder liners and the cylinder head portions. This would enable fabrication of a stronger, lighter cylinder head/block combination. An MMC insert could also be used to form the valve seat area to reduce cost and complexity. An MMC insert could also strengthen the integrated exhaust manifold and be used to control heat flow.

Since the crankcase 214 is a separate component it need not have to contain any coolant; therefore it can be made from materials usually attacked by water, e.g. magnesium.

The crankcase 216 is designed so that bolts e.g. 310, 311 are used to secure the crankcase 216 to the component 10; the bolts e.g. 310, 311 pass through both bearing surfaces of the crankcase and so pull the entire engine assembly together. Since the need for cylinder head studs is removed, an entire set of "critical fasteners" is omitted from the overall engine design when compared with a current standard' engine; this reduces the bill of material costs and the assembly cost and improves reliability.

In a "Vee" engine arrangement each batch of cylinders will be formed as an integrated cylinder block/head/manifold and the cylinder block/head/manifold components will be pulled into engagement with a common crankcase by bolts passing through the crankcase at an angle to the bearing panels of the crankcase so that the forces on the crankcase are triangulated. This will reduce the need for cross- bolting of a separate main bearing cap if used.

In both the in-line engine and the Vee engine designs, the crankcase used could be of a "bedplate" design or could have a separate main bearing cap.

The present invention is applicable to gasoline and diesel engines and indeed could be used for any engine regardless of fuel (e.g. a "hydrogen" engine) In a variant of the engine described above the poppet valves for each cylinder (and the cylinder head passages for the poppet valves) could be arranged each on an axis extending radially outward from a point located on the cylinder central axis. This would make tool access to the valve seats easier. With this arrangement the valve of each pair (inlet/exhaust) are not parallel to each other.

The cylinder liners used in the engine of the present invention could be parent bore, pressed-in or cast-in-place liners. If pressed-in liners are used then they could be pressed-in after the valve seats are machined, to ease machine-tool access to he valve seats.

- 10 - The liner 213 described above is a dry liner in that it is separated from the liquid coolant by a wall 218 of the component 201. This liner could be replaced by the wet liner 220 of Figure 5 which is threaded at the top part thereof and is threaded into engagement with a threaded portion 222 of the component 201. The cylinder liner 220 is directly exposed to coolant in the passage 221.

The engine described above has an exhaust manifold 204 in which three exhaust runners leading from three different cylinders are merged to a common outlet. However, the integrated exhaust manifold of the engine could comprise any number of exhaust runners merged to flow into a common outlet. Also, multiple exhaust manifolds could be integrated with a single cylinder block/head, for instance a six-cylinder engine might have two integrated exhaust manifolds, (each with three runners merging into a common outlet) or three integrated exhaust manifolds (each with a pair of runners merging into a common outlet) The engine of the present invention could also be provided with an integrated inlet manifold carrying an inlet common to a number of cylinders and inlet runners branching off from the common inlet, one for each cylinder. The engine could have a single integrated inlet manifold having inlet runners for all the cylinders or a plurality of integrated inlet manifolds, each supplying charge air to a sub-set of the total number of cylinders.

Claims

- 11 - CLA I MS

1. An internal combustion engine having a cylinder head and a cylinder block integrally formed as portions of a single first component, characterised in that the first component also has a manifold portion formed as an integral part thereof.

2. An internal combustion engine assembly comprising a first component which has both a cylinder head portion and a cylinder block portion integrally formed therein and a crankcase attached to the first component by mechanical fastening means characterised in that the first component also has a manifold portion formed as an integral part thereof.

3. An internal combustion engine as claimed in claim 1 or claim 2 wherein the manifold portion is an exhaust manifold portion having a plurality of exhaust runners which lead exhaust gases from a plurality of cylinders of the engine to a common outlet passage formed in the manifold portion.

4. An internal combustion engine as claimed in claim 1 or claim 2 wherein the manifold portion is an inlet manifold portion having a plurality of inlet runners which lead charge air from a common inlet passage formed in the manifold portion to a plurality of cylinders of the engine.

5. An internal combustion engine as claimed in claim 3 wherein the first component additionally has an inlet manifold portion formed as an integral part thereof, the inlet manifold portion having a plurality of inlet runners which lead charge air from a common inlet passage formed in - 12 the inlet manifold portion to a plurality of cylinders of the engine.

6. An internal combustion engine as claimed in claim 3 or 5 wherein coolant passages are defined in the first component and the coolant passages have parts that are arranged in the vicinity of the exhaust manifold to cool the exhaust manifold.

7. An internal combustion engine as claimed in any one of the preceding claims comprising a plurality of poppet valves which extend through passages provided in the cylinder head portion of the first component and which are engageable with valve seats defined in the surface(s) of the cylinder(s) provided in the first component.

8. An internal combustion engine as claimed in claim 7 wherein at least one of the valve seats surrounds a cylinder head part which spans both a surface forming a head part of a cylinder and a surface forming a bore part of the cylinder.

9. An internal combustion engine as claimed in claim 7 or claim 8 wherein for each cylinder the passages for the poppet valves lie in axes which extend radially out from a centre located on a central longitudinal axis of the cylinder.

10. An internal combustion engine as claimed in any one of the preceding claims comprising a direct injector which is located in the region where the cylinder head part and the cylinder block part meet.

- 13 -

11. An internal combustion engine as claimed in any one of the preceding claims wherein the first component is provided with one or more Metal Matrix Composite insert(s).

12. An internal combustion engine as claimed in any one of the preceding claims wherein a/the crankcase attached to the first component by mechanical fastening means is made without coolant passages.

13. An internal combustion engine as claimed in claim 12 wherein the crankcase is made of an alloy of magnesium.

14. A Vee configuration internal combustion engine comprising first and second components each of which has a cylinder head portion and a cylinder block portion integrally formed therein and both of which are connected to a common independently formed crankcase by mechanical fastening means, characterised in that each of the first and second components also has a manifold portion formed as an integral part thereof.

15. A method of fabrication of an internal combustion engine comprising: forming a single component with a cylinder head portion which provides a cylinder head of the engine and which is integrated with a cylinder block portion which provides a cylinder block of the engine, whereby the engine is provided wiLli tile cylinder head and Lhe cylinder block without a need for mechanised fasteners securing the cylinder head to the cylinder block; and - 14 - integrating in the said single component during forming thereof a manifold portion.

16. A method as claimed in claim 15 comprising providing the integrated manifold portion with a plurality of runners connected to a common flow passage.

17. A method as claimed in claim 16 wherein coolant passages are provided through the cylinder head portion, the cylinder block portion and the manifold portion.

18. A method of fabricating a Vee engine comprising: forming a pair of components each having a cylinder head portion, a cylinder block portion and a manifold portion integral with each other; securing the cylinder block portions of the pair of components by bolts to a common separately formed crankcase with the bolts attaching the cylinder block portions to the crankcase each extending at an angle to the bearing surface panels of the crankcase and also the bolts attaching one cylinder block portion to the crankcase extending at an angle to the bolts attaching the other cylinder block portion to the crankcase, whereby the engine is provided with cylinder heads and cylinder blocks without the need for mechanical fasteners to secure the cylinder heads to the cylinder blocks and the arrangement of bolts connecting the cylinder block portions to the crankcase provides a triangulation of forces; providing the engine with a plurality of cylinders; providing each cylinder head portion with passages and providing the engine with poppet valves extending through the passages; providing for the poppet valves a plurality of valve seats in surfaces of the cylinders; and arranging at least one of the valve seats to span both a surface of the cylinder head portion and a surface of a bore in the cylinder block portion.

18. A method as claimed in claims 15 to 17 wherein a separate crankcase component is formed without coolant passages and is fastened to the cylinder block portion by mechanical fastening means.

19. A method as claimed in any one of claims 14 to 17 wherein at least one Metal Matrix Composite insert is used to strengthen the cylinder head and/or cylinder block portions.

20. A method of fabricating a Vee engine comprising forming a pair of components each with an integral cylinder head portion, an integral cylinder block portion and an integral manifold portion, the cylinder block portions of the pair of components each being secured by bolts to a common separately formed crankcase with the bolts attaching the cylinder block portions to the crankcase each extending at an angle to the bearing surface panels of the crankcase and also the bolts attaching one cylinder block portion to the crankcase extending at an angle to the bolts attaching the other cylinder block portion to the crankcase, whereby the 15 - engine is provided with cylinder heads and cylinder blocks without the need for mechanical fasteners to secure the cylinder heads to the cylinder blocks and the arrangement of bolts connecting the cylinder bock portions to the crankcase provides a triangulation of forces.

631243; AWP; CTF Amendments to the claims have been filed as follows

CLAI MS

1. An internal combustion engine having a cylinder head and a cylinder block integrally formed as portions of a S single first component, wherein: the first component also has a manifold portion formed as an integral part thereof; the engine has one or more cylinders; the engine comprises a plurality of poppet valves which extend through passages provided in the cylinder head portion of the first component and which are engageable with valve seats defined in (a) surface(s) of the cylinder(s); and at least one of the valve seats spans both a surface of the cylinder head portion and a surface of a bore in the cylinder block portion.

2. An internal combustion engine assembly comprising a first component which has both a cylinder head portion and a cylinder block portion integrally formed therein and a crankcase attached to the first component by mechanical fastening means, wherein: the first component also has a manifold portion formed as an integral part thereof; the engine has one or more cylinders; the engine comprises a plurality of poppet valves which extend through passages provided in the cylinder head portion of the first component and which are engageable with valve seats defined in (a) surface(s) of the cylinder(s); and at least one of the valve seats spans both a surface of the cylinder head portion and a surface of a bore in the cylinder block portion.

3. An internal combustion engine as claimed in claim 1 or claim 2 wherein the engine has a plurality of cylinders and the manifold portion is an exhaust manifold portion having a plurality of exhaust runners which lead exhaust gases from the plurality of cylinders of the engine to a common outlet passage formed in the manifold portion.

4. An internal combustion engine as claimed in claim 1 or claim 2 wherein the engine has a plurality of cylinders and the manifold portion is an inlet manifold portion having a plurality of inlet runners which lead charge air from a common inlet passage formed in the manifold portion to the plurality of cylinders of the engine.

5. An internal combustion engine as claimed in claim 3 wherein the first component additionally has an inlet manifold portion formed as an integral part thereof, the inlet manifold portion having a plurality of inlet runners which lead charge air from a common inlet passage formed in the inlet manifold portion to the plurality of cylinders of the engine.

7. An internal combustion engine as claimed in any one of the preceding claims wherein for each cylinder the passages for the poppet valves lie in axes which extend radially out from a centre located on a central longitudinal axis of the cylinder.

8. An internal combustion engine as claimed in any one of the preceding claims comprising a direct injector which is located in the region.where the cylinder head portion and the cylinder block portion meet.

9. An internal combustion engine as claimed in any one of the preceding claims wherein the first component is provided with one or more Metal Matrix Composite insert (s) 10. An internal combustion engine as claimed in any one of the preceding claims wherein a/the crankcase attached to the first component by mechanical fastening means is made without coolant passages.

11. An internal combustion engine as claimed in claim 10 wherein the crankcase is made of an alloy of magnesium.

12. A Vee configuration internal combustion engine comprising first and second components each of which has a cylinder head portion and a cylinder block portion integrally formed therein and both of which are connected to a common independently formed crankcase by mechanical fastening means, wherein: each of the first and second components has at least one cylinder; each of the first and second components also has a manifold portion formed as an integral part thereof; the engine comprises a plurality of poppet valves which extend through passages provided in the cylinder head portion of the first and second components and which are engageable with valve seats defined in surfaces of the cylinders; and in each of the first and second components at least one of the valve seats spans both a surface of the cylinder head portion and a surface of a bore in cylinder block portion.

13. A method of fabrication of an internal combustion engine comprising: forming a single component with a cylinder head portion which provides a cylinder head of the engine and which is integrated with a cylinder block portion which provides a cylinder block of the engine, whereby the engine is provided with the cylinder head and the cylinder block without a need for mechanised fasteners securing the cylinder head to the cylinder block; and integrating a manifold portion in the said single component during forming thereof; providing the engine with one or more cylinder(s); providing the cylinder head portion with passages; and providing the engine with a plurality of poppet valves extending through the passages; H 25 providing for the poppet valves a plurality of valve seats in (a) surface(s) of the cylinder(s); and arranging at least one of the valve seats to span both a surface of the cylinder head portion and a surface of a bore in the cylinder block portion.

14. A method as claimed in claim 13 comprising providing the integrated manifold portion with a plurality of runners connected to a common flow passage.

15. A method as claimed in claim 14 comprising providing passages through the cylinder head portion, the cylinder block portion and the manifold portion.

16. A method as claimed in claims 13 to 15 wherein a separate crankcase component is formed without coolant passages and is fastened to the cylinderbiock portion by mechanical fastening means.

17. A method as claimed in any one of claims 13 to 16 wherein at least one Metal Matrix Composite insert is used to strengthen the cylinder had and/or cylinder block portions.