US3673990A

US3673990A - Internal combustion engines with at least two rows of cylinders with overhead camshafts

Info

Publication number: US3673990A
Application number: US65431A
Authority: US
Inventors: Giulio Alfieri
Original assignee: Officine Alfieri Maserati SpA
Current assignee: Maserati SpA
Priority date: 1969-08-25
Filing date: 1970-08-20
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: FR2059220A5; ES382996A1; DE2041964A1; GB1289580A

Abstract

A V-form internal combustion engine includes two rows of cylinders with overhead camshafts driven by an intermediate shaft arranged between the two rows of cylinders parallel to the latter and itself rotated by the crankshaft of the engine through a generally reducing transmission device. The two transmission devices include two drive gears keyed on the intermediate shaft at positions selected so that the corresponding driven gears borne by the camshafts are situated between two cams relating to two successive cylinders of the corresponding row of cylinders, whereby reduction in the length of the camshafts and in the engine cylinder heads is effected.

Description

United States Patent Alfieri 1 1 July 4,1972

[54] INTERNAL COMBUSTION ENGINES WITH AT LEAST TWO ROWS OF CYLINDERS WITH OVERHEAD CAMSHAFTS [72) Inventor: Giulio Altieri, Modena, Italy [73] Assignee'. Officine Alfieri Maserati, Modena, Italy [22] Filed: Aug. 20, 1970 [21] Appl No: 65,431

[58] Field of Search 123/9027, 90.31, 55 V, 195 A, 123/198, 52 R, 52 MV, DIG. 1, DIG, 6, DIG. 7

[56] References Cited UNlTED STATES PATENTS 1,173,105 2/1916 Fekete 123/195 A X 1,312,555 8/1919 McCain 123/55 V 1,424,428 8/1922 Vincent 123/9027 X FOREIGN PATENTS OR APPLICATIONS 421,359 9/1933 Great Britain .,123/90.3l

Primary ExaminerAl Lawrence Smith AtlomeyLarson, Taylor and Hinds [57] ABSTRACT A Vform internal combustion engine includes two rows of cylinders with overhead camshafts driven by an intermediate shaft arranged between the two rows of cylinders parallel to the latter and itself rotated by the crankshaft of the engine through a generally reducing transmission device, The two transmission devices include two drive gears keyed on the in terrnediate shaft at positions selected so that the corresponding driven gears borne by the camshafts are situated between two cams relating to two successive cylinders of the corresponding row of cylinders, whereby reduction in the length of the Camshafts and in the engine cylinder heads is effected 3 Claims, 4 Drawing Figures INTERNAL COMBUSTION ENGINES WITH AT LEAST TWO ROWS OF CYLINDERS WITH OVERHEAD CAMSHAFIS The invention relates to internal combustion engines including at least two similar rows of several cylinders in each of which the valves of the cylinders are actuated by at least one overhead camshaft; and it relates more particularly, because it is in this case that its application seems to have the most interest, but not exclusively, among these engines, to those of the V form type, especially for automobile vehicles.

It is a particular object of the invention to render engines of the type concerned such that they respond to the various desiderata of practice better than hitherto and especially so that they effect a reduction in bulk of the actuating mechanism for the camshafts and for certain accessories of the engine, and, preferably, so that it is possible, in addition, to use identical cylinder heads for the two rows of cylinders.

The internal combustion engine according to the invention comprises at least two similar rows of several cylinders in each of which the valves of the cylinders are actuated by at least one overhead camshaft, the camshaft of the two rows of cylinders being rotated, by means of two chain or notched belt and pinion transmission devices, by an intermediate shaft arranged between the said rows of cylinders parallel to the latter and itself rotated by the crankshaft of the engine through a generally reducing transmission device, the said engine being characterized by the fact that the two said transmission devices comprise respectively two drive gears keyed on the said intermediate shaft at emplacements selected so that the corresponding driven gears borne by the carnshafts are situated between two cams relating to two successive cylinders of the corresponding row of cylinders, this arrangement enabling reduction in the length of the camshafts and in the engine's cylinder heads.

Preferably, the driven gears of the two corresponding camshafts, belong respectively to two similar rows of several cylinders, occupy symmetrical positions with respect to the axis enabling the cylinder heads of the two rows of cylinders to be made to coincide theoretically by a rotation of 180 around their axis, whereby it is possible to adopt identical cylinder heads for the two said rows of cylinders, which obviously constitutes an economy in the cost of manufacture of the engine.

It will then, advantageously, be possible to arrange the intermediate shaft in the longitudinal plane of symmetry of the engine, so the two transmission devices relating respectively to the two camshafts of the two rows of cylinders are themselves identical, which enables an economy to be effected.

In addition, it is advantageous to use the said intermediate shaft for driving, directly or indirectly, accessories borne by the engine or by the structure equipped with this engine (body in the case of an engine for an automobile vehicle), the accessory transmission system, in the latter case, being advantageously capable of being a flexible transmission system protecting the said accessory from the vibrations of the engine.

If necessary or useful, the intermediate shaft could be made to include an extension intended to receive an accessory or a drive for the actuation of such an accessory.

Finally, with the object of licening, the intermediate shaft could advantageously be provided as tubular.

The invention relates more particularly, and this by way of new industrial products, to engines of the type concerned including the application of the previously explained features, as well as the special elements and tools adapted for their manufacture and the assemblies or installations, fixed or movable, especially automobile vehicles, equipped with similar engines.

In order that the invention may be more fully understood, a referred embodiment of an internal combustion engine according to the invention would be described below, purely by way of illustrative but non limiting example, with reference to the accompanying drawings, in which:

FIGS. 1 and 2, show, in diagrammatic manner, respectively in end view in the direction of the arrow I FIG. 2 and in plan of view, an embodiment of a V form engine constructed according to the invention; and

FIGS. 3 and 4, are diagrammatical cross-sections effected respectively along the lines III-III and IVIV of FIG. 2.

The engine shown in end view in FIG. 1 and in plan view in FIG. 2 is an internal combustion engine with two rows of several cylinders Ia and lb (for example four cylinders per row) arranged symmetrically with respect to the longitudinal plane P passing through the axis of the crankshaft 2 of the engrne.

The cylinders of one of the rows (identified in FIG. 2 by their respective plugs 3) are preferably slightly displaced longitudinally with respect to the cylinders of the other row, the two rows of cylinders having however a symmetry with respect to an axis XX situated in the plan P oriented perpendicularly to the axis of the crankshaft, which symmetry enables theoretically the row of cylinders Ia to be made coincide with the row of cylinders lb by rotation of the said row cylinders In by l around this axis XX.

Each row of the cylinders is equipped, for control of its valves, with at least one camshaft and, preferably, with two camshafis 40 for the row of cylinders 10 and 4b for the row of cylinders lb, two cams relating to the successive cylinders being denoted by the reference 4 on each of the respective camshaft.

There is then provided, to rotate the pairs of camshafts 4a and 4b, two chain (or notched belt) and pinion 6a and 6b transmission devices which will be more explicitly considered below and which are moved by an intermediate shaft 7 extending longitudinally between the rows of cylinders Ia and lb with, preferably, its axis situated in the plane of symmetry P, the abovesaid intermediate shaft 7 being itself driven by crankshaft of the engine by a reducing device, for example a chain 8 and

pinion

9 and 10 reducer as clearly shown in FIG.

This being the case and according to the main feature of the invention, the transmission devices 60 and 6b intended for the actuation of the pairs of camshafts 4a and 4b are ranged in emplacements such that, along the intermediate shaft 7, the driven gears (11a for the transmission device 6a and llb for the transmission device 6b) keyed on the camshafts are situated between the cams 5 relating to two successive cylinders of the row of the cylinders concerned as clearly visible in FIG. 2.

Preferably, it is arranged that the driven gears Ila, relating to one of the rows of cylinders Ia, have a symmetry, with respect to the axis of symmetry XX of the two rows of cylin ders, with the corresponding driven gears llb relating to the other row of cylinders, which enables then the provision of identical cylinder heads for the two rows of cylinders and of the two cylinder covers 12a and 12b (shown in mixed line in FIG. 2), also identical.

These cylinder head covers Ila and 12b can then be of H form with the transverse bar of the H displaced, the said bar being situated at the level of the corresponding transmission device 6a or 6b.

Each transmission system 6a and 6b can then include, as shown in FIG. 3 for the system 6a and FIG. 4 for the system 6b, a chain (13a or 13b) passing over the corresponding driven pinions (Ila or 11b), over a drive gear (14a or 14b) keyed on the intermediate shaft 7 and on a tensioner or 15b.

The intermediate shah 7 includes, on the opposite side to its drive gear 10, an extension 70 projecting beyond the rows of cylinders and on which is keyed the rotor of a rotary accessory such, for example, as a water pump 16.

The abovesaid shaft can also bear, in its part between two rows of cylinders, other rotary elements to actuate, for example a gear 17 for driving an ignition device and a drive means 18 for an external accessory.

There can then, advantageously, to lower the cost price of the engine, be constituted as the intennr. diate shaft 7 a single part in which are directly machined the various gears and drive means which have to be borne by the said shaft.

Finally, with the object of lightening, intermediate shaft 7 can be provided as tubular.

As a result of which, there is provided an internal combustion engine of which the advantages (compactness and simplicity of drives of the camshafts and of the accessories, identical cylinder heads, especially) result sufficiently clearly from the preceding description, so that it is unnecessary to enter, on the subject, into further complementary explanation.

As is selfevident, and as emerges already besides from the preceding description, the invention is in no way limited to that of its methods of application, nor to those of its methods of production of its various parts, which have been more particularly envisaged, it embraces, on the contrary, all variations.

1 claim:

1. In an internal combustion engine comprising at least two similar rows of several cylinders, an interchangeable overhead camshaft drive arrangement, wherein the camshafts of the two rows of cylinders are rotated, through two chain or notched belt transmission devices and gears, through an intennediate shaft arranged between said rows of cylinders parallel to the latter and itself rotated by the crankshaft of the engine through a generally reducing transmission device, the two said transmission devices including respectively two drive gears keyed on the said intermediate shaft at positions selected so that the corresponding driven gears borne by the camshafts are situated between two cams relating to two successive cylinders of the corresponding row of cylinders, whereby reduction in the length of the camshafts and in the engine cylinder head is effected, wherein the driven gears of two corresponding camshafts, belonging respectively to the two similar rows of several cylinders, occupy symmetrical positions with respect to the axis enabling the cylinder heads of the two rows of cylinders to be made theoretically to coincide by rotation through around the said axis, whereby it is possible to adopt identical cylinder heads for the two said rows of cylinders.

2. lntemal combustion engine according to claim 1, wherein the intermediate shaft is arranged in the longitudinal plane of symmetry of the engine, so the two transmission devices relating respectively to the two camshalts of the two rows of cylinders are themselves identical.

3. lntemal combustion engine according to claim I, wherein said engine is of the V-form type.

Claims

1. In an internal combustion engine comprising at least two similar rows of several cylinders, an interchangeable overhead camshaft drive arrangement, wherein the camshafts of the two rows of cylinders are rotated, through two chain or notched belt transmission devices and gears, through an intermediate shaft arranged between said rows of cylinders parallel to the latter and itself rotated by the crankshaft of the engine through a generally reducing transmission device, the two said transmission devices including respectively two drive gears keyed on the said intermediate shaft at positions selected so that the corresponding driven gears borne by the camshafts are situated between two cams relating to two successive cylinders of the corresponding row of cylinders, whereby reduction in the length of the camshafts and in the engine cylinder head is effected, wherein the driven gears of two corresponding camshafts, belonging respectively to the two similar rows of several cylinders, occupy symmetrical positions with respect to the axis enabling the cylinder heads of the two rows of cylinders to be made theoretically to coincide by rotation through 180* around the said axis, wHereby it is possible to adopt identical cylinder heads for the two said rows of cylinders.

2. Internal combustion engine according to claim 1, wherein the intermediate shaft is arranged in the longitudinal plane of symmetry of the engine, so the two transmission devices relating respectively to the two camshafts of the two rows of cylinders are themselves identical.

3. Internal combustion engine according to claim 1, wherein said engine is of the V-form type.