GB2045864A - Internal combustion engines having lubrication means - Google Patents

Abstract

Gutter-forming ribs 74, 79 are arranged on the valley walls 19 and 20 of a V-type internal combustion engine to intercept excess lubricant passing downwardly to the oil sump 24 and direct it firstly to the individual valve actuating cams 56 of the camshaft 57 and secondly to the lower portions of the piston skirts 31 extending below their respective cylinders 17 at the bottom of their travel. <IMAGE>

Description

SPECIFICATION Internal combustion engines having lubrication means This invention relates to internal combustion engines having lubrication means.

It is conventional in V-type internal combustion engines to provide a cylinder block having walls defining two V-arranged banks of cylinders with a valley between the banks and a crank chamber below. Pistons are provided in the cylinders and have skirts engaging the cylinder walls, the pistons being connected to a crankshaft for reciprocation of the pistons in the cylinders. The cylinders are commonly provided with valves controlling access to the combustion chambers, and with means for actuating the valves that are engageable with the cams of a camshaft which is longitudinally arranged in the valley between the banks and is driven by the crankshaft.It is further conventional to provide a pressure lubrication system through which lubricating oil is delivered from an oil sump below the engine crank chamber to the moving parts of various components of the valve actuating means, the excess oil being directed back to the sump, at least in part, through an open passageway through the valley between the cylinder banks, and running along the walls thereof before dropping through the crank chamber to the oil sump.

In engines as described, means may be specially provided, or may inherently exist, for lubrication of the camshaft cams which actuate the valve mechanism and for lubrication of the cylinder walls and the piston skirts which reciprocate within the cylinders in engagement with the walls. In some cases, lubrication of these components is adequately taken care of by the throw-off or splash of oil from rotation of the engine crankshaft and the mechanism attached thereto. In other cases, separate pressurelubricating devices have been provided for spraying oil on to the camshaft cams and the cylinder walls or the piston skirts in order to provide adequate lubrication for these parts.The provision of such additional lubricating means generally adds to the cost of manufacture of an engine, and is therefore resorted to only in cases where adequate lubrication is not provided by the crankshaft throw-off and spiash oil distributed within the engine crank member and commonly penetrating upwardly into the cylinder bank valley.

By the present invention there is provided an internal combustion engine having walls defining two V-arranged banks of cylinders, a valley between the banks and a crank chamber below, the pistons in the cylinders having skirts engaging the cylinder walls, the pistons being connected to a crankshaft for reciprocation in the cylinders, valves controlling access to each of the cylinders, valve actuating means engageable with cams of a camshaft arranged longitudinally in the valley and connected to the crankshaft for rotation of the camshaft to actuate the valves, and means for lubricating the valve actuating means and for directing excess lubricant down the valley walls to the crank chamber for return to an oil sump below, including gutterforming ribs provided along portions of the valley walls to intercept returning lubricant flowing downwardly therealong and direct it to below-disposed working parts of the engine for lubricating these parts.

The gutter-forming ribs can readily be cast integral with the walls of the valley at appropriate locations: for lubricating the cams of a camshaft located within the valley, this may be around the valve liftercarrying lifter gallery immediately above the camshaft, and for lubricating the skirts of the pistons as these skirts extend below their respective cylinders at the lower portions of their strokes into a portion of the crank chamber below the valley, this may be on the valley walls near their lower ends immediately above the bottoms of the respective cylinders. The provision of gutters by means of cast-in ribs in this manner can be accomplished at little or no additional cost, since it can be effected during the initial casting of the cylinder block.

In the accompanying drawings: Figure 1 is a tranverse cross-sectional view of one embodiment of a V-type internal combustion engine in accordance with the present invention; Figure2 is a longitudinal view of the engine of Figure 1, illustrating lubrication means for working parts of the engine; Figure 3 is a fragmentary top view of a portion of the engine block, on the line 3-3 of Figure 1, in the direction of the arrows, illustrating features of camshaft lubrication means; Figure 4 is a fragmentary cross-section on the line 4-4 of Figure 3, in the direction of the arrows, illustrating the shape of an upper group of gutterforming ribs; Figure 5 is a fragmentary cross-section on the line 5-5 of Figure 3, in the direction of the arrows, further illustrating the upper gutter-forming rib configuration;; Figure 6is a fragmentary cross-sectional view of the engine block looking downwardly from the plane of line 6-6 of Figure 1, and illustrating features of piston skirt lubricating means; Figure 7 is a fragmentary cross-section on the line 7-7 of Figure 6, in the direction of the arrows, showing the configuration of a lower group of gutter-forming ribs; and Figure 8 is a fragmentary cross-section on the line 8-8 of Figure 6, in the direction of the arrows, further illustrating the lower gutter-forming rib configuration.

In the drawings, reference numeral 10 generally indicates a six-cylinder V-type internal combustion piston engine intended primarily for automotive vehicle application. The engine 10 includes a cast and machined cylinder block 11 including a lower crankcase section 12 defining a crank chamber 14 and supporting thereabove left and right-hand banks 15 and 16 respectively of cylinders (as viewed from the rear of the engine, and thus in the opposite direction from the direction of view of Figure 1). The cylinder banks 15 and 16 are arranged in V fashion with a 60 bank angle. The inner walls 19 and 20 of the left and right-hand cylinder banks respectively define a generally V-shaped open section intermediate the cylinders that is commonly referred to as a valley 21.

An oil pan 23, mounted on the bottom of the crankcase section 12 of the cylinder block, provides a sump 24 for containing a supply of lubricating oil for the engine and encloses the lower part af the crank chamber 14. A crankshaft 25 is rotatably supported in conventional fashion by the cylinder block within the crank chamber, and includes a plurality of crank throws 27 connected by connecting rods 28 to pistons 29 reciprocably movable within respective ones of the six cylinders 17 of the engine.

The pistons include respective skirts 31 which engage the walls of their respective cylinders 17 and form bearing surfaces through which the thrust load acting between the pistons and the cylinder-walls are carried. Upon rotation of the crankshaft, the pistons reciprocate in their respective cylinders, moving between upper and lower dead centre positions, the latter being such that the lower portions of the piston skirts 31 extend below the lower edges of their respective cylinders into the upper portion of the crank chamber. This is illustrated by phantom lines with respect to the piston shown in the right-hand cylinder bank 16 of Figure 1, and by solid lines for the centre cylinder shown in Figure 2.

The upper ends of the cylinders 17 are closed by left and right-hand bank cylinder heads 32 and 33 mounted respectively on the upper ends of the cylinder banks 15 and 16. The cylinder banks carry conventional outboard-mounted exhaust manifolds 35 and 36 which may be supplied with secondary air through air supply valves 37, only one of which is shown. An intake manifold 39 mounted between the cylinder heads 32 and 33 covers the open top of the valley 21, and in turn supports a carburettor 4Q on which an aircleaner41 is mounted.

The cylinder heads are provided with inlet and exhaust ports 43 and 44 respectively, for communication of their respective cylinders with the intake and exhaust manifolds and other portions of the engine intake and exhaust systems. The respective ports are controlled by inlet and exhaust valves 45 and 47 respectively, which are actuated by valve gear including valve springs 48, rocker arms 49, push rods 51 and hydraulic valve lifters 52, the latter being carried in the bores 53 of bosses 55 formed as extensions of the valley walls 19 and 20 and defining a valve lifter gallery. The valve lifters 52 are actuated by the cams 56 of a camshaft 57 which is rotatably supported in the cylinder block, extending longitudinally through the valley 21 below the lifter gallery bosses 55.A driven gear 59 is connected by means of a drive chain 60 to a drive gear 61 on the crankshaft, thus providing a driving connection for the engine camshaft.

The engine 10 is provided with a pressure lubrication system including an oil pump 63 which is driven from a distributor drive gear 64 located near the rear end of the camshaft, and is connected to an intake strainer 65 through which oil is drawn by the pump from the engine oil sump. The pump directs oil through various passages in the engine block and moving components to lubrication points including the various bearing journals of the crankshaft and camshaft. Oil is also supplied directly to the valve lifters 52 and from them through the push rods to the rocker arms 49, which are enclosed by rocker covers 67 mounted on the tops of the cylinder heads and the adjacent intake manifold.The oil used in lubricating the valve gear components, as well asthe excess oil supplied to these components, is returned to the engine sump by gravity-impelled flow downwardly alo.ng upper and innersurfacesofthe cylinder heads, through the open push-rod spaces defined between the cylinder heads and the intake manifold and into the valley 21, and running along the walls 19 and 20 thereof to the lower inner edge of the cylinders, at which point openings 72 are provided through which the oil passes into the crank chamber and thence is returned to the oil sump below.

In conformity with the present invention, along the walls 19 and 20 there are provided upper and lower groups of gutter-forming ribs arranged specifically to intercept the excess lubricating oil being returned from lubrication of the upper portions of the valve gear and passing downwardly along the valley walls, and to direct this oil on to the cams 56 of the camshaft and subsequently, at least in part, on to the innersides of the skirts 31 of the various pistons in order to provide for adequate lubrication of the cams, the piston skirts and the associated cylinder walls. As is best seen in Figures 2 to 5, there is an upper group of gutter-forming ribs 74, which extend from points 75 near the upper edges of the cylinder block downwardly around the lifter gallery bosses 55, with one set of ribs being provided at each cylinder location.Each set of the upper group of ribs 74 is arranged to intercept a major portion of the returning oil utilized for lubricating the components of its respective cylinder location. This oi! is directed downwardly through gutters 76 extending around the sides of the lifter gallery bosses 55, the gutters terminating at points along openings 78 immediately above the respective cams 56 of the camshaft, so that the collected oil is directed on to the surfaces of the cams for lubrication thereof.

Moving further downwardly along the inner sides of the valley walls 19 and 20, some of the oil passing the upper group of ribs 74, in addition to that used for lubricating the camshaft bearings, is intercepted near the lower edges of the engine cylinders by a group of gutter-forming ribs 79 best seen in Figures 2 and 6 to 8. The ribs 79 extend longitudinally in both directions from the planes of their adjacent cylin ders, defining gutters 80 which collect oil from the valley wall surfaces immediately outside the respective cylinders and direct the oil to V-like openings 82 formed at the lower edges of the respective valley walls, which correspond to the bottom edges of the respective cylinders. From here the oil collected by the gutters is directed on to the outer surfaces of the lower portions of the piston skirts 31 when they reach the lower portions of their strokes, thus providing lubrication for both the piston skirts and their respective cylinders upon subsequent upward movement of the pistons. The gutter-forming ribs 79 of the lower group are likewise arranged in sets, and are effective to collect oil flowing down the walls at each of the various cylinder locations, this being oil which has primarily been utilized in the lubrication of operative elements of the valve gear and other moving parts associated with the respective cylinders, and this collected oil being used for providing adequate lubrication of the inner piston skirts 31.

The provision of the upper and lower groups of gutter-forming ribs, with sets of these ribs being associated with respective cylinder locations, in conformity with the present invention, makes available added lubrication for moving components of the engine, notably the camshaft cams and piston skirts, through means provided entirely as a part of the engine block casting and thus obtainable at a minimum manufacturing cost, and without the need for additional oil usage.

Claims (4)

1. An internal combustion engine having walls defining two V-arranged banks of cylinders, a valley between the banks and a crank chamber below, pistons in the cylinders having skirts engaging the cylinder walls, the pistons being connected to a crankshaft for reciprocation in the cylinders, valves controlling access to each of the cylinders, valve actuating means engageable with cams of a camshaft arranged longitudinally in the valley and connected to the crankshaft for rotation of the camshaft to actuate the valves, and means for lubricating the valve actuating means and for directing excess lubricant down the valley walls to the crank chamber for return to an oil sump below, including gutter-forming ribs provided along portions of the valley walls to intercept returning lubricant flowing downwardly therealong and direct it to below-disposed working parts of the engine for lubricating these parts.

2. An internal combustion engine according to claim 1, in which the valley includes a valve lifter gallery, with the camshaft arranged longitudinally in the valley below the lifter gallery, and gutter-forming ribs as aforesaid extend along the lifter gallery walls in the valley at each cylinder location to intercept lubricant passing down the walls at each said location and direct it to the various cams of the camshaft disposed below the lifter gallery and associated with the respective cylinder at each said location.

3. An internal combustion engine according to claim 1 or 2, in which the skirts of the pistons have lower portions extending below the bottoms of the cylinders at the lower extent of their travel, and gutter-forming ribs as aforesaid are provided along lower portions of the valley walls at each cylinder location to intercept returning lubricant flowing therealong and direct it to positions atthe inner edges near the bottom of each respective cylinder for lubricating the associated piston skirts by delivery of the intercepted lubricant on to their skirt lower portions as they extend below their cylinders at their lower extent of travel.

4. An internal combustion engine substantially as hereinbefore particularly described and as shown in the accompanying drawings.