FR3122916A1 - Engine block with oil deflector - Google Patents

Abstract

Engine block with oil deflector Engine block (5) for a combustion engine (3), characterized in that it comprises:- a side opening (16) opening out into a volume (V) intended to accommodate a balancing (9) rotatably mounted, - at least one upstream oil pipe (14) terminating in an upper wall (24) of said volume (V), - at least one downstream oil pipe (15) emerging from a wall (25) of said volume (V),- means (23) for closing off the lateral opening (16), the means for closing (23) comprising a deflector (26) configured to deflect an oil flow from the upstream oil line (14) out of a swept volume (VB) by the rotation of the balance shaft (9) and to the downstream oil line (15). Figure for abstract: Figure 2

Description

Engine block with oil deflector

Technical field of the invention

The invention relates to an engine block for a combustion engine. The invention also relates to a combustion engine comprising such an engine block. The invention also relates to a powertrain comprising such an engine block and/or such a combustion engine. The invention also finally relates to a motor vehicle comprising such a powertrain.

State of the prior art

Combustion engines for motor vehicles generally include one or more balance shafts to dampen the vibrations generated by the movement of the pistons and the connecting rods. The balance shaft(s) are usually built into sides of an engine block of the combustion engine, which places them in the natural path of oil return lines from the cylinder head to the oil pan. Abundant contact between the oil and the balancer shaft causes damage and/or oil emulsion which is harmful to the operation of the engine. Thus, it is known to provide oil return lines bypassing the balancing shaft or shafts. Such pipes increase the complexity of the engine block and require the use of more expensive engine block manufacturing processes such as foundry with a sand core. In addition, the engine blocks obtained are also more bulky.

Another known solution is to introduce a duct in the balance shaft area to isolate it from the oil return flow. This solution is complex and requires the manufacture and fixing of specific parts.

Presentation of the invention

The object of the invention is to provide a combustion engine remedying the above drawbacks and improving the combustion engines known from the prior art.

More precisely, a first object of the invention is a combustion engine comprising a balance shaft which is simple to manufacture, of small size, and which prevents abundant contact between lubricating oil and a balance shaft. .

The invention relates to an engine block for a combustion engine, comprising:
- a side opening opening into a volume intended to accommodate a balance shaft mounted rotatably,
- at least one upstream oil pipe terminating in an upper wall of said volume,
- at least one downstream oil pipe emerging from a lower wall of said volume,
- means for closing off the side opening, the means for closing off comprising a deflector configured to divert an oil flow coming from the upstream oil line out of a volume swept by the rotation of the shaft counter and to the downstream oil line.

The deflector can extend around the volume swept by the rotation of the balancing shaft over an angular portion covering an outlet of the at least one upstream oil pipe in the upper wall.

The closure means can include a closure plate closing the side opening, and the deflector can be remote from the closure plate.

The engine block may comprise two bores intended to accommodate two bearings supporting the balance shaft, the lateral opening extending opposite a space defined between the two bores.

The engine block may include an arrangement configured to allow oil flow to at least one bearing supporting the balance shaft, in particular a free space formed between the deflector and a body of the engine block.

The deflector may comprise a rounded wall around the volume swept by the rotation of the balance shaft.

A body of the engine block can be obtained by high pressure casting.

The closure means can be one-piece and obtained by plastic injection.

The engine block may comprise at least two upstream oil pipes terminating in the upper wall of said volume and at least two downstream oil pipes emerging from the lower wall of said volume, the deflector being configured to deflect oil flows coming from from the at least two upstream oil lines out of the volume swept by the rotation of the balance shaft and to the at least two downstream oil lines.

The invention also relates to a combustion engine comprising an engine block as defined above, a balancing shaft rotatably mounted in said volume, a cylinder head from which the at least one upstream oil pipe emerges, and a oil sump in which the at least one downstream oil pipe ends.

The invention also relates to a powertrain comprising a combustion engine as defined above and a lubrication system, the lubrication system comprising an oil pump, a high pressure oil circuit and a low pressure oil circuit , said at least one upstream pipe and said at least one downstream pipe being arranged in the low-pressure oil circuit.

The invention also relates to a motor vehicle comprising an engine block as defined above, and/or a combustion engine as defined above, and/or a powertrain as defined above.

Presentation of figures

These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment given on a non-limiting basis in relation to the attached figures, among which:

The is a schematic view of a motor vehicle according to one embodiment of the invention.

The is a perspective view of an engine block with a means for closing a side opening according to one embodiment of the invention.

The is a perspective view of the engine block of the without the means of obturation.

The is a perspective view of the closure means.

The is a partial sectional view along an XZ plane of the engine block and a balance shaft.

The is a partial sectional view along a YZ1 plane of the engine block and the balancer shaft.

The is a partial sectional view along a YZ2 plane of the engine block and the balancer shaft.

detailed description

The schematically illustrates a motor vehicle 1 according to one embodiment of the invention. The vehicle 1 can be of any kind, in particular a private vehicle, a utility vehicle, a truck or a bus. The vehicle is assumed to rest on horizontal ground. The vertical Z axis is an axis perpendicular to the horizontal surface. The terms "upper" and "lower", "top" and "bottom" refer to an arrangement along the vertical Z axis.

The vehicle 1 comprises a powertrain 2 provided with a combustion engine 3 and a lubrication system 4. The combustion engine 3 is an engine comprising a set of pistons movable within cylinders and whose movement is caused by the combustion of a fuel. The fuel can be gasoline, diesel, or even any other type of fuel such as ethanol or liquefied petroleum gas.

The combustion engine 3 comprises an engine block 5, sometimes also referred to as a cylinder block, in which are arranged a plurality of cylinders 6 intended to accommodate pistons. The engine block 5 can comprise any number of cylinders, for example three, four, six or eight cylinders. According to the embodiment presented, the engine comprises four cylinders in line. The cylinders 6 are oriented substantially vertically, that is to say that the pistons arranged inside these cylinders are designed to slide according to a back and forth movement parallel to the vertical axis Z.

The combustion engine 3 further comprises a cylinder head 7 positioned vertically above the engine block 5 and an oil sump 8, or lower engine, positioned vertically below the engine block 5. The combustion engine also comprises a set moving parts such as a crankshaft, connecting rods, and camshafts. In particular, the crankshaft is rotatable around an axis of rotation perpendicular to the Z axis. An X axis is defined as an axis parallel to the axis of rotation of the crankshaft and a Y axis as the axis perpendicular to the axis. axis and the Z axis. The X, Y and Z axes form an orthogonal frame.

In particular, the combustion engine comprises at least one balancing shaft 9. The balancing shaft 9 is a shaft extending parallel to the axis X and comprising counterweights 10 to reduce the vibrations of the engine due to the movement pistons and connecting rods. The balance shaft is thus driven in rotation and synchronized with the rotation of the crankshaft. The combustion engine 3 can comprise a second balancing shaft, in particular when the engine comprises four cylinders. The invention, described here in relation to a first balancing shaft, can be transposed to any other balancing shaft of the combustion engine.

The lubrication system 4 makes it possible to lubricate the contact between various moving parts of the combustion engine, in particular the crankshaft, the camshafts, the connecting rods and the balance shafts. It comprises an oil pump 11, a high pressure oil circuit 12 and a low pressure oil circuit 13. The high pressure oil circuit 12 is arranged from the oil pump 11 to the components to be lubricated and the low pressure oil circuit 12 is arranged from the members to be lubricated up to the oil pump 11. The oil circulates in the high pressure oil circuit thanks to the pressure generated by the oil pump 11. The oil circulates in the low pressure oil circuit due to the effect of gravity. The combustion engine is therefore a "gravity" type engine because it uses the effect of gravity for its operation.

The low pressure oil circuit comprises various oil lines 14, 15 cut into the body of the engine block. The oil lines 14, 15 are commonly referred to as oil return lines because they make it possible to guide the oil towards the oil sump after it has been projected to lubricate the components to be lubricated. These oil pipes are arranged substantially vertically in the body of the engine block and allow the oil present at the level of the cylinder head to be lowered towards the oil sump. The oil accumulated in the oil sump is pumped by the oil pump to re-lubricate the various components to be lubricated in the combustion engine, thus creating a closed oil circuit.

In relation to the and the , a body of the engine block 5 is described in more detail. The body of the engine block 5 is a metal block which can be obtained by a molding process. In particular, the body of the engine block may for example be made of cast iron or aluminum. Advantageously, the body of the engine block is obtained by high pressure casting, a process also known by the English acronym HPDC (meaning “high pressure die casting”). Such a process makes it possible to produce large engine blocks, in large quantities and at high speed. It further enables engine blocks to be obtained with high precision, superior surface finish, excellent uniformity, relatively thin walls and optimum mechanical properties. As a variant, the casing could also be manufactured by other methods such as for example casting using a sand core.

The body of the engine block 5 has a roughly parallelepipedal shape: an upper face 17 is intended to face the cylinder head and a lower face is intended to face the oil sump. A first lateral face 18, called the exhaust face 18, extends generally parallel to the X axis and to the Z axis on one exhaust side of the combustion engine, that is to say on the same side as combustion engine exhaust valves. This side is opposite a second lateral face of the engine block, called the intake face because it is on the same side as the intake valves of the combustion engine.

The engine block 5 further comprises a side opening 16 (clearly visible on the ) opening into a volume V intended to accommodate the balance shaft 9. The opening 16 is arranged on a lateral side of the engine block, in particular on the exhaust face 18 of the engine block 5. Alternatively, this opening could also be arranged on the intake face. As clearly visible on the , the opening 16 has a generally rectangular shape. The large side of the rectangle extends parallel to the axis X of rotation of the crankshaft. The opening 16 extends over a major part of the length of the engine block parallel to the axis X, for example of the order of 50% of the length of the engine block along the axis X. In particular, the opening 16 uncovers two uprights 19 in each of which are arranged a bore 20 intended to accommodate a bearing supporting the balance shaft 9 (the term bore designating an opening of cylindrical shape). In other words, the opening 16 extends at least between the two bearings supporting the balancing shaft. The opening 16 also uncovers the whole of the counterweight 10 of the balance shaft 9. The opening 16 can extend substantially below the set of cylinders of the engine block. The opening 16 can be positioned substantially towards the middle of the exhaust face of the engine block.

The opening 16 is bordered by a flat face 21, generally parallel to the X and Z axes, and pierced with holes 22 useful for fixing a closure means 23. The opening 16 is mainly intended to facilitate the manufacturing process by molding the engine block: During the process of molding the engine casing, part of the mold is engaged in the volume V made accessible by the opening 16, which makes it possible to generate by molding the interior contour of this volume V and in particular all the reliefs it contains. The presence of this opening therefore makes it possible to avoid delicate machining steps and/or makes it possible to manufacture the engine block with simple molding processes such as a high-pressure casting process. This opening is intended to be sealed off by the sealing means 23 so that the oil does not escape from the engine block during its operation.

According to the embodiment shown, three upstream oil pipes 14 end in an upper wall 24 of volume V, that is to say they are arranged above volume V and open into volume V. Each of the three upstream oil lines 14 can be arranged substantially between two neighboring cylinders. In addition, three downstream oil pipes 15 protrude from a lower wall 25 of the volume V, that is to say they are arranged below the volume V and protrude from the volume V. Alternatively, the number upstream and/or downstream oil lines could be different, for example one, two or more than three upstream and/or downstream oil lines. The upstream and downstream oil lines are oil return lines. They extend substantially vertically and are intended to be traversed by oil flowing from top to bottom under the effect of gravity. Advantageously, the three downstream oil pipes 15 can be arranged at low points of the lower wall 25 so as to avoid any stagnation of oil in the volume V.

The closure means 23 comprises a deflector 26 configured to deflect an oil flow coming from the upstream oil pipes 14 out of a volume VB swept by the rotation of the balance shaft 9 and towards the oil pipes. downstream oil 15. The volume VB swept by the rotation of the balancing shaft 9 designates all the points of space likely to be occupied by the balancing shaft 9 during a rotation around of its axis of rotation. Due to the presence of counterweights 10, the balancing shaft 9 does not have rotational symmetry and the volume VB swept by the rotation of the balancing shaft 9 is greater than the balancing volume as such. The volume VB is notably illustrated schematically by a dotted line in FIGS. 5 to 7.

The closure means 23 is particularly clearly visible on the . It comprises a closure plate 27 which is substantially planar and intended to bear against the planar face 21 bordering the opening 16. The closure plate 27 comprises a set of holes coinciding with the holes 22 for screw fixing of the closure means 23 to the engine block 5. The deflector 26 comprises a rounded wall 28 around the volume VB swept by the rotation of the balance shaft 9. The wall 28 has the overall shape of a tube portion. The wall 28 also comprises, in the upper part, a planar portion inclined downwards and towards the closure plate 27. The section of the wall 28 parallel to the Y and Z axes may roughly have the shape of a J. Ribs 29 are provided between the wall 28 and the closure plate 27 to link them to each other. A space 30 is provided between the closure plate 27 and the wall 28 of the deflector 26 to allow the oil to flow therefrom. The deflector is therefore remote from the closure plate. Advantageously, the fixing plate comprises a shape slightly domed towards the outside of the engine block so as to guarantee a space 30 wide enough for easy evacuation of the oil, even if the latter is particularly viscous. A notch 31 is provided in the wall 28 to avoid interference with an upright 19 of the engine block supporting a bore 20. Thus, a first portion of the wall 28 extends substantially between the two uprights 19 while a second portion of the wall 28 extends on the other side of one of the two uprights 19. The wall 28 extends to below the upstream oil pipes 14. It comprises a descending profile allowing the oil to escape. flow along this wall by gravity. Advantageously, the closure means is in one piece and obtained by plastic injection. It is therefore both light and simple to manufacture. As a variant, it could also be made of metal, for example by assembling several sheet metal plates previously cut and shaped.

The is a sectional view parallel to the X axis and to the Z axis of the engine block 5 and of the balancing shaft 9, according to the XY plane identified on the . In this cross-sectional view, two bearings 32 mounted in the bores 20 and supporting the balancing shaft 19 can be distinguished in particular. The bearings 32 may be rolling bearings, in particular needle bearings. Advantageously, the engine block comprises an arrangement configured to allow oil flow to at least one bearing supporting the balance shaft. According to the embodiment presented, this arrangement consists of free spaces 33 between the edges of the deflector 26 and the body of the engine block 5. The dimensions of these free spaces can be adjusted so as to allow a greater or lesser quantity to escape. oil coming from the upstream oil line 14. In particular, the ribs 29 form ledges on the surface of the wall 28 whose height can be adjusted in order to allow more or less oil to pass towards the bearings 32. Oil can thus reach the balance shaft and lubricate the bearings 32. Alternatively, the arrangement allowing the lubrication of the bearings could also consist of holes provided in the wall 28.

Figures 6 and 7 are two sectional views of the engine block and the balance shaft along two planes YZ1 and YZ2, perpendicular to the axis X. It is observed that the upstream oil pipes 14 can be offset from to the downstream oil lines 15 along the X axis and/or along the Y axis. The deflector can be designed to be mounted without direct contact with the body of the engine block. The wall 28 preferably extends under the entire upstream oil pipe covering the outlet of the upstream oil channel 14 in the volume V. Thus, whatever the zone of the upstream oil pipe 14 against which the oil trickles, it then flows over the wall 28. According to the embodiment shown, the deflector 26 has a shape compatible with an assembly of the closure means subsequent to the establishment of the balance shaft , according to a translational movement parallel to the Y axis. This induces a guiding of the oil on the side of the closing plate 27. balancing shaft, between the balancing shaft and a wall defining the bottom of the volume V.

For the manufacture of the combustion engine, the body of the engine block can first be manufactured by high-pressure casting. The presence of the opening 16 makes it possible to obtain directly by molding specific shapes of the volume V accommodating the balance shaft. Then the balancing shaft 9 and the bearings 32 can be inserted by inserting them along the X axis. Finally, the opening 16 is closed by bringing the closing means 23 together along the Y axis and screwing it into the body of the engine block with screws 34. As a variant, other fixing means could be envisaged, in particular riveting, crimping or welding. Thus, by one and the same operation, the opening 16 is closed and the deflector 26 is put in place, making it possible to deviate a flow of oil from the volume swept by the rotation of the balance shaft.

When the combustion engine is running, the balancing shaft 9 rotates around its axis of rotation. At the same time, the oil is circulated through the lubrication system. After having been projected under pressure to lubricate the components of the cylinder head, the oil descends again under the effect of gravity, passing through the upstream oil pipes 14. The oil then arrives on the upper face of the wall 28. A large part of the oil flows along the wall 28 and is guided around the balance shaft without contact with it. This prevents damage to the oil by allowing it to come into abundant contact with the balance shaft. The formation of oil emulsion is also avoided. The oil having bypassed the balance shaft reaches the downstream oil pipes 15 directly or flows over the lower wall 25 before joining the downstream oil pipes, before ending up in the oil sump 8 in sunken. This path of the oil is represented by arrows in FIGS. 6 and 7. A smaller part of the oil coming from the upstream oil lines 14 flows through the free spaces 33 and is sufficient to lubricate the bearings 32 Thanks to the invention, a combustion engine is available that is compact and simple to manufacture. A single assembly operation is necessary to close the opening 16 and to mount a means for diverting the flow of the oil.

Claims (12)

Engine block (5) for a combustion engine (3), characterized in that it comprises:
- a lateral opening (16) opening into a volume (V) intended to accommodate a balancing shaft (9) rotatably mounted,
- at least one upstream oil line (14) terminating in an upper wall (24) of said volume (V),
- at least one downstream oil pipe (15) emerging from a lower wall (25) of said volume (V),
- a closure means (23) of the lateral opening (16), the closure means (23) comprising a deflector (26) configured to deflect an oil flow coming from the upstream oil pipe ( 14) out of a swept volume (VB) by the rotation of the balance shaft (9) and towards the downstream oil line (15).
Engine block (5) according to the preceding claim, characterized in that the deflector extends around the swept volume (VB) by the rotation of the balancing shaft (9) over an angular portion covering an outlet of the au at least one upstream oil line (14) in the top wall (24).
Engine block (5) according to one of the preceding claims, characterized in that the closing means (23) comprises a closing plate (27) closing the lateral opening (16), and in that the deflector (26 ) is remote from the closure plate (27).
Engine block (5) according to one of the preceding claims, characterized in that it comprises two bores (20) intended to accommodate two bearings (32) supporting the balance shaft (9), the opening (16) side extending opposite a space defined between the two bores (20).
Engine block (5) according to one of the preceding claims, characterized in that it comprises an arrangement configured to allow a flow of oil towards at least one bearing supporting the balance shaft, in particular a free space (33) formed between the deflector (26) and a body of the engine block.
Engine block (5) according to one of the preceding claims, characterized in that the deflector (26) comprises a wall (28) rounded around the swept volume (VB) by the rotation of the balance shaft.
Engine block (5) according to one of the preceding claims, characterized in that a body of the engine block is obtained by high-pressure casting.
Engine block (5) according to one of the preceding claims, characterized in that the closure means (23) is in one piece and obtained by plastic injection.
Engine block (5) according to one of the preceding claims, characterized in that it comprises at least two upstream oil pipes (14) terminating in the upper wall (24) of said volume (V) and at least two downstream oil (15) emerging from the lower wall (25) of said volume (V), the deflector (26) being configured to deflect oil flows coming from the at least two upstream oil pipes (14) out of the swept volume (VB) by rotation of the balance shaft and to the at least two downstream oil lines (15).
Combustion engine (3), characterized in that it comprises an engine block (5) according to one of the preceding claims, a balancing shaft (9) rotatably mounted in the said volume (V), a cylinder head (7) from which emerges the at least one upstream oil pipe (14), and an oil sump (8) in which the at least one downstream oil pipe (15) ends.
Powertrain (2) comprising a combustion engine (3) according to the preceding claim and a lubrication system (4), the lubrication system comprising an oil pump (11), a high pressure oil circuit (12) and a low pressure oil circuit (11), said at least one upstream pipe (14) and said at least one downstream pipe (15) being arranged in the low pressure oil circuit (11).
Motor vehicle (1), characterized in that it comprises an engine block (5) according to one of Claims 1 to 9 and/or a combustion engine (3) according to Claim 10, and/or a powertrain ( 2) according to the preceding claim.