ENGINE HAVING INTEGRATED EXHAUST MANIFOLD WITH COMBINED DUCTS FOR INSIDE CYLINDERS AND OUTSIDE CYLINDERS

Abstract

An internal combustion engine has a cooling jacket at least partially integrated in the cylinder head. The engine has two groups of cylinders: inside cylinders and outside cylinders. Each cylinder has at least one exhaust port, each leading to an individual duct. Individual ducts of outside cylinders converge to form an outside combined duct. In a four-cylinder engine or cylinder head, individual ducts of inside cylinders converge to form an inside combined duct with the inside combined duct remaining separated from the outside combined duct by the cooling jacket. The inside combined duct is farther away from the mounting surface of the cylinder head to the cylinder block than the outside combined duct. The cooling jacket includes upper, middle, and lower cooling jackets and connectors between the upper and lower cooling jackets.

Claims

1. An engine having a cylinder head with at least two exhaust ports per cylinder, comprising: a pair of individual ducts associated with each cylinder and coupled to the at least two exhaust ports; a paired duct coupled to each pair of individual ducts; an outside combined duct coupled to paired ducts of a first group of cylinders; and an inside combined duct coupled to paired ducts of a second group of cylinders, wherein the outside combined duct is separated from the inside combined duct and cylinders of the first group are each separated in firing order by firing of a cylinder in the second group.

2. The engine of claim 1 wherein the first group of cylinders comprises cylinders proximate an end of the engine and the second group of cylinders comprises cylinders interposed the first group of cylinders.

3. The engine of claim 1 wherein the engine includes only three cylinders and the cylinder head includes one inside cylinder and two outside cylinders.

4. The engine of claim 1 wherein the engine includes only four cylinders and wherein the cylinder head includes two inside cylinders, the cylinder head further comprising: an inside combined duct coupled to a paired duct of inside cylinders, the inside combined duct being separated from the outside combined duct by a cooling jacket.

5. The engine of claim 1 wherein the cylinder head has a mounting surface adapted to be mounted to a cylinder block of the engine, the cylinder head further comprising: a lower cooling jacket disposed between the mounting surface and the outside combined duct; a middle cooling jacket disposed between the inside combined duct and the outside combined duct; an upper cooling jacket disposed between a side of the cylinder head mounting surface and the inside combined duct; and connectors coupling the lower cooling jacket with the upper cooling jacket.

6. An engine having a cylinder head with two exhaust ports per cylinder, comprising: a pair of individual ducts for each cylinder coupled to the two exhaust ports; a paired duct coupled to each pair of individual ducts; an inside combined duct coupled to paired ducts of a first cylinder group; and an outside combined duct coupled to a second cylinder group with cylinders separated in firing order by a cylinder in the first group.

7. The engine of claim 6 wherein the first cylinder group includes cylinders proximate ends of the engine and the second cylinder group includes cylinders disposed between the cylinders of the first cylinder group.

8. The engine of claim 7 wherein the engine includes only three cylinders.

9. The engine of claim 6 wherein the engine includes only four cylinders and the cylinder head includes two inside cylinders, the cylinder head further comprising: an inside combined duct coupled to a paired duct of inside cylinders, the inside combined duct being separated from the outside combined duct by a cooling jacket.

10. The engine of claim 6 wherein the cylinder head has a mounting surface configured to be mounted to a cylinder block of the engine, the cylinder head further comprising: a lower cooling jacket disposed between the mounting surface and the outside combined duct; a middle cooling jacket disposed between the inside combined duct and the outside combined duct; an upper cooling jacket disposed between a side of the cylinder head mounting surface and the inside combined duct; and connectors coupling the lower cooling jacket with the upper cooling jacket.

11. An engine having at least two exhaust ports per cylinder, comprising: a cylinder head comprising: a pair of individual ducts per cylinder coupled to the exhaust ports, a paired duct coupled to each pair of individual ducts, and an outside combined duct coupled to paired ducts of outside cylinders, wherein each of the outside cylinders is separated in firing order by firing of one of the inside cylinders.

12. The engine of claim 11 wherein the outside combined duct is separated from paired ducts of inside cylinders by a cooling jacket.

13. The engine of claim 11 wherein the outside cylinders are proximate an end of the engine and the inside cylinder are disposed between the outside cylinders.

14. The engine of claim 11 wherein the cylinder head has a mounting surface adapted to be mounted to a cylinder block of the engine, the cylinder head further comprising: a lower cooling jacket disposed between the mounting surface and the outside combined duct; a middle cooling jacket disposed between the inside combined duct and the outside combined duct; an upper cooling jacket disposed between a side of the cylinder head mounting surface and the inside combined duct; and connectors coupling the lower cooling jacket with the upper cooling jacket.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a perspective view of a sand core of exhaust gas ducts integrated in the cylinder head according to an embodiment of the disclosure;

[0019] FIG. 2 is a side of view of the sand core illustrated in FIG. 1;

[0020] FIG. 3 is a perspective view of the sand core of the cooling jacket integrated in the cylinder head according to an embodiment of the disclosure;

[0021] FIG. 4 is a side view of the sand core illustrated in FIG. 3 as viewed in the direction of the longitudinal axis of the cylinder head;

[0022] FIG. 5 is a top of view of a portion of the sand core illustrated in FIG. 3;

[0023] FIG. 6 is a side view of the sand core illustrated in FIG. 3 as viewed perpendicularly with respect to the longitudinal axis of the cylinder head; and

[0024] FIG. 7 is a perspective view of the cylinder head according to an embodiment of the disclosure.

DETAILED DESCRIPTION

[0025] As those of ordinary skill in the art will understand, various features of the embodiments illustrated and described with reference to any one of the Figures may be combined with features illustrated in one or more other Figures to produce alternative embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for particular applications or implementations. Those of ordinary skill in the art may recognize similar applications or implementations consistent with the present disclosure, e.g., ones in which components are arranged in a slightly different order than shown in the embodiments in the Figures. Those of ordinary skill in the art will recognize that the teachings of the present disclosure may be applied to other applications or implementations.

[0026] FIG. 1 shows a perspective view of a sand core 1 for forming the exhaust gas ducts 4a, 4b, 5, 6, 6 adapted to be integrated in a cylinder head according to an embodiment of the disclosure. The example in FIG. 1 is a four-cylinder, in-line engine in which the cylinders are arranged along a longitudinal axis of the cylinder head. Each cylinder has two exhaust ports 3a, 3b and individual exhaust duct 4a, 4b coupled to each exhaust port 3a, 3b. The cylinders form two groups: one group including outside cylinders and the other group including inside cylinders. Each pair of individual exhaust ducts 4a, 4b converge to form a paired exhaust duct 5. The paired exhaust ducts 5 of inside cylinders converge to form an inside combined duct 6. Similarly, the paired exhaust ducts 5 of outside cylinders converge to form an outside combined duct 6. The ducts associated with inside cylinders remain separated from ducts associated with outside cylinders within the cylinder head. The ducts associated with inside cylinders form an inside integrated manifold 2 and the ducts associated with outside cylinders form an outside integrated manifold 2. The inside manifold integrated manifold 2 is separated from the outside manifold integrated manifold 2.

[0027] Sand cores are shown in FIGS. 1-6. The ducts, as described in regard to FIGS. 1 and 2 are formed of sand. However, in a cylinder head, shown in FIG. 7, the sand is removed and the ducts are passageways defined in the cylinder head. For convenience, ducts 3a, 3b, 4a, 4b, 5, 6, 6 are described as ducts even though in FIGS. 1 and 2, they are illustrated by the sand core. Similarly, the sand core for cooling passages is shown in FIGS. 3-6, but referred to as passages for convenience; and, again with the understanding that in the cylinder head, the sand is removed and the cooling passages are defined in the cylinder head.

[0028] In a three-cylinder engine, there is only one inside cylinder. Thus, there is no inside combined duct 6. Instead the paired duct 5 exits the cylinder head directly, in an engine with two or more exhaust ports. If the engine has a single exhaust valve, the individual duct 4a exits the cylinder head directly.

[0029] In the exhaust system in FIG. 1, the combined ducts 6, 6 are offset from each other along the longitudinal axis of the cylinder head. The inside combined duct 6 of the second integrated exhaust manifold 2 is further away from the mounting surface than the second integrated exhaust manifold 2. The mounting surface of the cylinder head is the surface proximate the engine block as mounted on the engine block; a cylinder head is shown in conjunction with FIG. 7.

[0030] FIG. 2 shows the sand core 1 illustrated in FIG. 1 in a side view in the direction of the longitudinal axis of the cylinder head. The same reference symbols as in FIG. 1 are used for the same components.

[0031] FIG. 3 shows a perspective illustration of the sand core 7 for forming the cooling jacket 8 integrated in the cylinder head according to a first embodiment.

[0032] The cooling jacket 8 comprises: a lower cooling jacket 8a, which is arranged between the exhaust gas ducts and a mounting end face (not shown in FIG. 3), of the cylinder head; an upper cooling jacket 8b, which is arranged on that side of the exhaust gas ducts 5 which lies opposite the lower cooling jacket 8a; and a middle cooling jacket 8c which is arranged between the overall exhaust gas ducts 6, 6, bends inwardly and consequently follows the run of the second integrated exhaust manifold (see also FIG. 2).

[0033] In an outer wall of the cylinder head (shown in FIG. 7), out of which the overall exhaust gas ducts 6, 6 emerge, two connectors 9 are provided which connect the lower cooling jacket 8a to the upper cooling jacket 8b and serve as a passage for coolant. The two connectors 9 are arranged on opposite sides of the overall exhaust gas ducts 6, 6 and are themselves connected to one another via the middle cooling jacket 8c.

[0034] The lower and the upper cooling jackets 8a, 8b are not connected to one another over the entire region of the outer wall, but only over a portion of the outer wall, specifically adjacent to the overall exhaust gas ducts 6, 6. The two connectors 9 are arranged adjacent to the region in which the cylinder head is subjected to particularly high thermal load.

[0035] The longitudinal flows in the direction of the longitudinal axis of the cylinder head, which occur in the upper, lower, and middle cooling jackets 8a, 8b, 8c, are supplemented by the two cross flows in the connectors 9 (see also FIG. 5).

[0036] To remove the sand core 7 after the casting of the cylinder head, in the region of the connectors 9, two accesses 10 are provided which are closed after the removal of the sand core 7 so that the connectors 9 are integrated completely in the outer wall.

[0037] FIG. 4 shows the sand core 7 illustrated in FIG. 3 in a side view looking in the direction of the longitudinal axis of the cylinder head. The same reference symbols as in FIG. 3 are used for the same components, and therefore reference is otherwise made to FIG. 3.

[0038] As shown in FIG. 4, an additional connector 11, serving as the passage of coolant, is provided between the lower cooling jacket 8a and the upper cooling jacket 8b. Moreover, an additional access 12 for removing the sand core 7 and for machining the additional connector 11 is provided, which is closed again in the finished cylinder head. A coolant inlet 13 is used for feeding coolant into the lower cooling jacket 8a and a coolant outlet 14 is used for discharging coolant out of the upper cooling jacket 8b.

[0039] FIG. 5 shows a top view of the parts of the sand core illustrated in FIG. 3, which form the lower and the middle cooling jacket 8a, 8c, specifically in the direction of the cylinder longitudinal axes. The same reference symbols as in FIG. 3 are used for the same components. The directions of flow of the coolant through the cooling jackets 8a, 8c are depicted as arrows. The coolant flows in the form of a fan from the coolant inlets of the lower cooling jacket 8a into the middle cooling jacket 8c, specifically through the two connectors 9 in the outer wall and the additional connector 11.

[0040] FIG. 6 shows the sand core 7 illustrated in FIG. 3 in a side view looking perpendicularly with respect to the longitudinal axis of the cylinder head. The same reference symbols as in FIGS. 3 and 4 are used for the same components.

[0041] The coolant flows from the outer coolant inlets 13 of the lower cooling jacket 8a along the longitudinal axis of the cylinder head to connectors 9 and vertically through connectors 9 into the middle and lower cooling jackets 8a, 8c.

[0042] The upper cooling jacket 8b likewise has two outside coolant inlets 15, the coolant discharged from the cooling jacket 8 via the coolant outlet 14.

[0043] A cylinder head 16 is shown in FIG. 7 with the longitudinal axis 18 shown as a dash-dot line. A mounting surface 20 is an underside of cylinder head 16 as viewed in FIG. 7. Mounting surface 20 is proximate the cylinder block when installed. An exterior surface of the exhaust ducts 25, 25 can be seen in FIG. 7. Exhaust ducts 25 carry exhaust gases from outside cylinders and converge to form a combined exhaust duct 26. Similarly, exhaust ducts 25 carry exhaust gases from outside cylinders and converge to form a combined exhaust duct 26. In the case of an engine with one exhaust port per cylinder, ducts 25, 25 are individual ducts from the single exhaust ports. In the case of an engine with multiple exhaust ports per cylinder, ducts 25, 25 are paired exhaust ducts which are coupled to individual exhaust ducts joining the multiple individual exhaust ducts from one cylinder. Combined exhaust ducts 26 and 26 exit cylinder head 16 at an outer wall 28.

[0044] While the best mode has been described in detail, those familiar with the art will recognize various alternative designs and embodiments within the scope of the following claims. For example, cylinders with one or two exhaust ports per cylinder are described. However, the disclosure can be extended to cylinders having more than two exhaust ports per cylinder. Where one or more embodiments have been described as providing advantages or being preferred over other embodiments and/or over prior art in regard to one or more desired characteristics, one of ordinary skill in the art will recognize that compromises may be made among various features to achieve desired system attributes, which may depend on the specific application or implementation. These attributes include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As an example, for cost reasons, a steering apparatus may be provided on two of the four wheels, in some applications. The embodiments described as being less desirable relative to other embodiments with respect to one or more characteristics are not outside the scope of the disclosure as claimed.