Camshaft drive for engine

#This invention relates to a camshaft drive for an engine and more particularly to an improved camshaft drive arrangement for an overhead camshaft that permits a compact engine construction.

#In substantially all engine applications, there is a large demand for more compact engine constructions. This is particularly true in connection with automotive applications. One particularly demanding situation in an automotive application is when the engine is positioned transversely in the chassis. Such transverse placement normally substantially limits the number of cylinders that can be used because of the length constraints.

#Where overhead camshafts are employed, the camshafts are normally driven off of the crankshaft by a timing mechanism that is generally provided at one end of the crankshaft. Such arrangements have a number of difficulties, not the least of which is the fact that this type of a drive generally adds to the overall length of the engine.

#FIG. 1 is a partial side elevational view of an internal combustion engine constructed in accordance with a prior art type of construction with the cam cover and intermediate shaft drive cover removed so as to more clearly show the construction.

#FIG. 2 is a side elevational view, in major parts similar to FIG. 1, but shows the construction in accordance with an embodiment of this invention.

#FIG. 3 is a top plan view showing the relationship between the crankshaft, the camshaft and the intermediate shaft.

#Referring now in detail to the drawings, an internal combustion engine constructed in accordance with an embodiment of the invention is indicated generally by the reference numeral 51. Like the description of the prior art engine in FIG. 1, the illustrated embodiment of the invention is not a complete drawing of the engine. Since the invention deals primarily with the camshaft drive arrangement, only these components have been shown in detail. Therefore, where any components of the engine 51 are not illustrated, they may either be considered to be conventional or of a structure as shown in the aforenoted U.S. Pat. No. 5,134,144.

#The engine 51 is comprised of a cylinder block assembly 52 and a cylinder head assembly 53 that is detachably connected thereto. The cylinder block assembly 52 forms a number of aligned cylinder bores and the like the prior art type of construction, the engine 51 may be of the five cylinder, inline type.

#Pistons contained within the cylinder bores are connected by means of connecting rods to the throws 54 of a crankshaft, indicated generally by the reference numeral 55. The crankshaft 55 has main bearing portions 56 that are suitably journaled within the cylinder block 52 within a crankcase chamber that is closed by a crankcase member which is not shown in the drawing for the aforenoted reasons. At least some of the throws 54 are counter-balanced at least in part by a counter-weight portions 57.