EP0942155B1 - Internal combustion engine with anti-foaming device - Google Patents

Description

The present invention relates to the field anti-bubbling devices mounted in the oil sumps of internal combustion engines intended in particular to equip vehicles automobiles.

An internal combustion engine includes, in general, a cylinder block receiving a cylinder head its upper end and an oil pan at its lower end. The lubrication circuit of such an engine conventionally comprises a pump driven by the crankshaft and which sucks the oil stored in the oil pan to send it, after filtration, through pipes suitable for moving engine parts, such as crankshaft bearings, connecting rods, pistons or camshaft, oil returns then by gravity in the oil pan.

The oil slick contained in the sump of oil being subjected to the movements of the vehicle, moves and is therefore likely to come to crankshaft and crankshaft contact with for consequence a loss of power resulting from a such bubbling. To prevent this phenomenon, it is known to have a screen isolating the crankshaft and the connecting rod of the oil slick contained in the oil pan.

Document FR-A-2.650.033 discloses by example, a screen in the form of a plate in shaped sheet to protect crankshaft and crankshaft, oil contained in the crankcase oil and oil falling from the cylinder head.

In accordance with the state of the art known, the splash screens are fixed by screws directly on the bearing caps of the crankshaft or even directly on corresponding bosses carried by the housing oil or the cylinder block. Such a provision has the disadvantage of complicating motor assembly and increase the cost of this last.

The object of the present invention is to remedy this drawback by proposing an engine with an easy-to-splash prevention device mount and requiring no fixing means reported.

The internal combustion engine according to the invention is of the type comprising a cylinder block inside which is housed a crankshaft connected to pistons by connecting rods, a oil pan and means forming an anti-splash screen to prevent the oil slick contained in the oil pan to come into contact with the crankshaft and connecting rods.

According to the invention, the means forming a screen are immobilized in position simply by pinching of a plurality of holding tabs between the lower edge of the cylinder block and the corresponding edge of the oil pan.

According to another characteristic of the internal combustion object of the invention, the legs support are housed in a groove corresponding seal interposed between the oil pan and the cylinder block.

According to another characteristic of the internal combustion object of the invention, the positioning of the screen means is ensured by ribs extending under the legs of maintenance.

According to another characteristic of the internal combustion object of the invention, the means forming a screen include housings intended for come to fit on bearing caps of the crankshaft to ensure prepositioning during their mounting on the cylinder block.

According to another characteristic of the internal combustion object of the invention, the means forming a screen have fixing arms clip-on allowing their hanging on the cylinder block.

According to another characteristic of the internal combustion object of the invention, the means forming a screen have boxes open towards the oil pan intended in particular to limit the displacement of the oil slick.

According to another characteristic of the internal combustion object of the invention, the means forming a screen are formed by a monobloc shell obtained in molded plastic.

• la figure 1 est une vue en coupe transversale partielle d'un carter-cylindres et d'un carter d'huile d'un moteur à combustion interne équipé d'un écran anti-barbotage selon l'invention ;
• la figure 2 est une vue similaire à la figure 1 précisant le montage de la plaque anti-barbotage entre le carter-cylindres et le carter d'huile.

The aims, aspects and advantages of the present invention will be better understood from the description given below of an embodiment of the invention, given by way of non-limiting example, with reference to the accompanying drawings, wherein :

• Figure 1 is a partial cross-sectional view of a cylinder block and an oil pan of an internal combustion engine equipped with an anti-bubbling screen according to the invention;
• Figure 2 is a view similar to Figure 1 showing the mounting of the anti-bubbling plate between the cylinder block and the oil pan.

According to the figures, only the elements of the engine necessary for understanding of the invention have been figured, moreover in facilitate reading the same elements bear the same references from one figure to another.

Referring to Figure 1, we have shown the lower end forming a base of a combustion engine cylinder block 1 internal multi-cylinder type in line. AT the inside of this cylinder block are housed with classic way of pistons connected to a crankshaft by connecting rods.

The base of the cylinder block 1 has a peripheral edge or sidewalk 2 extending in projecting perpendicular to the side walls of the cylinder block 1 towards the inside of the latter, towards the crankshaft. Against this edge peripheral 2 of cylinder block 1 comes to take press the corresponding peripheral edge 4 of the oil pan 3.

The fixing of the oil sump 3 on the cylinder block 1 is secured by screws not figured cooperating with the peripheral edges above 2 and 4 forming a flange and counter flange. Between the cylinder block 1 and the oil pan 3 is interposed a type 5 seal elastomer housed in a groove formed on the edge device 4 of the oil pan 3. Dimensions of seal 5 are suitable for obtaining a rate predetermined compression when the edge device 4 comes into contact with edge 2.

According to the invention, an anti-splash screen 6 is interposed between the cylinder block 1 and the oil pan 3 in order to prevent the oil in the oil pan does not come into contact with the crankshaft and crankshaft. This anti-splash screen 6 is produced in the form a one-piece molded plastic shell, such as a glass fiber filled polyamide. Screen 6 is shaped to wrap around the bottom of the crankshaft not shown and also the crankshaft not shown.

The anti-splash screen 6 has a shape general semi-cylindrical corresponding substantially to the envelope curve of the trajectories crankshaft and crankshaft. The dimensions of screen 6 are adjusted to leave a clearance extremely reduced between screen and hitch mobile of the order of a few millimeters.

Screen 6 has openings 13 arranged substantially under each of the connecting rods. These openings are oriented transversely in the direction of motor rotation, to evacuate oil splashes from the lower engine (piston, connecting rods, journals, crank pins, etc.) to the housing oil.

Screen 6 following the shape of the hitch mobile has walls 8 facing crankshaft bearing caps. These walls 8 form transverse boxes 15 open at direction of the oil pan. The boxes 15 isolate the crankshaft peer to peer and the connecting rod of the oil slick and on the other hand they make it possible to stiffen the screen 6.

The boxes 15 define on the other hand partitions on the underside of screen 6 which have the advantage of limiting the movement of the oil slick in the sump oil 3 and therefore planing. So the pump aspiration remains primed even in case of significant movements of the oil.

All or part of the walls 8 present by elsewhere shoulders 7 coming framed lateral edges of the bearing caps 12. These shoulders thus allow to operate the pre-positioning of screen 6 on the caps of bearing when mounted on the cylinder block 1.

Immobilization in position of the screen 6 is ensured by a plurality of lugs holding 10 projecting transversely relative to to the side edges of the screen 6 which come pinch between the edge 2 arranged at the base of the cylinder block 1 and the edge corresponds 4 to the housing oil 1 with interposition of the seal 5.

To do this, the seal 5 presents a transversely opening groove suitable for receive the retaining tabs 10. It is thus possible to tighten the holding tabs 10 of the splash screen 6 without affecting the tightness of the oil pan assembly 3 on the cylinder block 1.

Thus immobilization in position of the anti-splash screen 6 is operated without means of attachment reported only by pinching the retaining lugs 10 between the cylinder block 1 and the oil pan 3. Interposition of the seal sealing 5 allows the use of materials weakly elastic to make screen 6 and also makes it possible to compensate for any manufacturing deviations of the latter.

To ensure perfect positioning of the screen 6 between the cylinder block 1 and the housing oil 3, cleats or ribs of positioning 11 are arranged under the legs of maintenance 10. These cleats are intended to come immobilize the side edges of the screen 6 against the corresponding side edges of the oil pan 3.

The anti-splash screen 6 presents by elsewhere clipping arms 9 allowing the holding the screen on the cylinder block when disassembly of the oil pan 3 or during engine assembly operations on chains mounting. The arms 9 which are shaped for have some elasticity, whatever the material used, have at their end a protruding rim intended to come to rest on the edge 2 formed at the base of the cylinder block 1.

Introducing the arms through the lower opening of the cylinder block takes place simply by elastic deformation of the arms which once released come to rest on edge 2, as shown in Figure 1.

Of course, the invention is by no means limited to the embodiment described and illustrated which was only given as an example.

On the contrary, the invention includes all technical equivalents of the means described as well as their combinations if these are performed following his spirit.

Thus the present invention applies also for engines with housing beams cap interposed between the cylinder block and the oil pan. In this case the mounting of the screen is operated between the hat beam and the oil pan.

Claims (7)

1. An internal combustion engine of the type comprising a crankcase (1), in the interior of which is accommodated a crankshaft connected to pistons by connecting rods, an oil sump pan (3) and means (6) forming an anti-splash screen for preventing the layer of oil contained in the oil sump pan from coming into contact with the crankshaft and the connecting rods characterised in that said screen-forming means (6) are immobilised in position simply by a plurality of holding lugs (10) being gripped between the lower edge (2) of the crankcase (1) and the corresponding edge of the oil sump pan (3).
2. An internal combustion engine according to claim 1 characterised in that said holding lugs (10) are accommodated in a corresponding groove of the sealing gasket (5) interposed between the oil sump pan (3) and the crankcase (1).
3. An internal combustion engine according to either one of claims 1 and 2 characterised in that positioning of said screen-forming means (6) is effected by ribs (11) extending under the holding lugs (10).
4. An internal combustion engine according to any one of claims 1 and 3 characterised in that the screen-forming means (6) comprise housings (7) intended to come into engagement over bearing caps of the crankshaft in order to ensure pre-positioning of the screen-forming means (6) upon mounting thereof on the crankcase (1).
5. An internal combustion engine according to any one of claims 1 to 4 characterised in that said screen-forming means (6) comprise clippable fixing arms (9) permitting them to be hooked on to the crankcase (1).
6. An internal combustion engine according to any one of claims 1 to 5 characterised in that said screen-forming means (6) comprise wells open towards the oil sump pan (3) in particular to limit movements of the layer of oil.
7. An internal combustion engine according to any one of claims 1 to 6 characterised in that said screen-forming means (6) are formed by a case (6) produced in moulded plastic material.

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