EP2450536B1 - Engine for motorbike - Google Patents

Description

Field of the invention

The invention relates to a motorcycle four-stroke engine using splash lubrication.

More particularly, the invention relates to a motor four-stroke internal combustion engine comprising at least one piston cooperating with at least one connecting rod and a crankshaft to rotate the crankshaft along a horizontal crankshaft axis, a bath housing oil under the crankshaft, a splash lubrication system comprising a spoon secured to the rod and extending towards the housing.

The invention also relates to a motorcycle equipped with such an engine.

State of the art

Motorcycle four stroke engines with a splash lubrication system have been known for at least a hundred years.

Initially, the crankshaft of such engines partially plunged into an oil bath contained in the crankcase, which, due to the rotational movement of the crankshaft, caused and sprayed oil on parts of the engine requiring lubrication. This was for example the case of the engines fitted to the "Henderson Four" motorcycles that were produced by the American firm Henderson Motorcycle Co in 1912.

This principle of lubrication was quickly abandoned in favor of pressure lubrication systems, ie using oil pumps to bring the oil to the parts to be lubricated, which in particular allowed better control of the lubrication.

Nevertheless, bubble lubrication is still used today, mainly for small stationary engines, such as portable generators, where still for small agricultural machines such as tillers and other lawn mowers, but also for motorcycle engines . The advantage of such a system is its simplicity and low cost.

This lubrication system was improved over time. In recent engines, it is no longer the crankshaft that bubbles in the crankcase oil, but an elongated piece, often called "spoon", secured to the connecting rod connecting the piston to the crankshaft and whose distal end plunges into the crankcase. the oil from the crankcase to draw oil and drive and project this oil on parts of the engine requiring lubrication.

For example, there is known such a motorcycle motor by the Japanese patent published under the number JP 2004218488 (Suzuki Motor co).

In such a known engine, the crankshaft axis is horizontal and, when the motor is mounted on a motorcycle, this crankshaft axis is perpendicular to the running direction of the motorcycle. Accordingly, an orbital plane in which the spoon moves when the engine is in operation is a plane parallel to a plane formed by a non-steering wheel of the motorcycle. This orbital plane is a vertical plane when the bike is stationary and balanced on its two wheels.

As the bike rolls and turns, the driver tilts the bike sideways and in the direction of the turn to ensure balance. This equilibrium is achieved when the vector sum of the gravitational force and the centrifugal force to which the motorcycle and the driver are subjected result in a force directed towards a point of contact between the motorcycle and the ground. When the bike comes out of a turn to resume a straight line, the driver straightens the bike in a substantially vertical position to ensure the same balance. When several turns in the opposite direction (left / right) succeed each other, the driver successively tilts the motorcycle on either side of the vertical plane.

In these various rolling situations, the orbital plane of the spoon obviously follows the same inclination movement as that of the motorcycle, while the crankcase oil, because of its inertia, does not immediately follow this movement. This has the effect of lowering the oil level at the spoon, so that this height may become insufficient for the spoon can draw oil, which will have the effect that the lubrication of the engine does not will not be done or insufficiently.

This problem will be all the more marked as the turns will be tight and / or the speed of the bike will be great. Such circumstances occur for example on racing circuits or on circuits normally provided for karting. On karting circuits, this problem will also be accentuated by the fact that the bike will take a quick sequence of successive turns.

Although it is not specifically a motorcycle engine, there is also a similar engine of the US patent published under the number US 2,449,227 and the French patent published under the number FR 698978 .

The housing of these known engines comprises, within its volume and on either side of an orbital plane of the spoon, walls forming an obstacle to a movement of the crankcase oil.

However, these walls do not ensure sufficient lubrication of the engine in the running conditions of a motorcycle.

Summary of the invention

An object of the invention is to provide a motorcycle motor which provides better lubrication of the engine in the rolling situations described above as well as in other situations likely to cause lubrication problems similar to those described above. .

To this end, the engine according to the invention is characterized in that the housing comprises, within its volume and on either side of an orbital plane of the spoon, at least one wall forming an obstacle to a movement of the crankcase oil, each wall extending substantially transversely to the axis of the crankshaft and rising from a lower portion of the housing to a top of a distal end of the spoon when said spoon is in a lowest position.

When an engine according to the invention is mounted transversely on a motorcycle to propel it and when the motorcycle changes inclination relative to a vertical plane - this is for example the case when the motorcycle enters or exits a corner or when a bend changes curvature or when the speed of the motorcycle varies during a turn - the walls will partially inhibit or prevent the oil from moving laterally relative to the orbital plane of the spoon, thus ensuring a height of greater oil in said orbital plane than in the absence of such walls. In particular, the oil level in the Orbital plane will thus be maintained above the distal end of the spoon when said spoon is in a lowest position, which will continue to lubricate the engine.

Another advantage of an engine according to the invention is that, if the oil level in the crankcase is, under real conditions of use, below a recommended minimum level but nevertheless above the end distal from the spoon when said spoon is in its lowest position, the lubrication of the engine will still be assured, and this in more extreme driving conditions with a conventional engine. Indeed, by the same effect of the walls on the lateral movement of the oil, it will maintain a height of oil in the orbital plane of the spoon which is greater than in the absence of such walls.

It should be noted that, in general, the walls need not necessarily be contiguous to inner faces of the casing, since they are arranged in a fixed manner in the interior volume of the casing.

However, it is preferable that side and bottom edges of the walls are close to the inner faces of the housing. This prevents the oil from moving too easily between the walls and the inner faces of the housing, which would have the effect of reducing the desired effect.

Preferably, the engine according to the invention is characterized in that the wall forms a partition in the casing and in that the wall has a height less than a minimum oil level recommended in the housing.

Indeed, when the walls form a partition in the housing, that is to say when the side and bottom edges of the walls are contiguous to the inner faces of the housing, the desired effect is better. Furthermore, when the walls have a height less than a minimum oil level recommended for the engine, that is to say when the walls are fully immersed in the oil when the engine is stopped, the oil , which will naturally tend to be partially transferred from one compartment to the other of the casing when the engine is inclined laterally, will distribute again substantially equally between the compartments when the engine reverses its direction of inclination (left / right or right / left).

Brief description of the figures

Fig.1

montre schématiquement des coupes frontales d'un moteur connu et selon plusieurs positions d'inclinaison latérales du moteur ;

Fig.2

montre schématiquement une coupe AA du moteur de la Fig.1 lorsqu'il n'est pas incliné;

Fig.3

montre schématiquement des coupes frontales d'un moteur ne faisant pas partie de l'invention, et selon plusieurs positions d'inclinaison latérales du moteur;

Fig.4

montre schématiquement une coupe BB du moteur de la Fig.3 lorsqu'il n'est pas incliné;

Fig.5, 6A et 6B

montrent schématiquement des coupes frontales d'un moteur ne faisant pas partie de l'invention le moteur n'est pas incliné ;

Fig. 7A et 7B

montrent schématiquement des coupes frontales d'un moteur selon des modes de réalisation particuliers de l'invention lorsque le moteur n'est pas incliné ;

Fig.8

montre schématiquement une vue de face arrière d'une moto équipée d'un moteur selon l'invention.

These and other aspects of the invention will be clarified in the detailed description of particular embodiments of the invention, with reference to the drawings of the figures, in which:

Fig.1

shows schematically front sections of a known engine and according to several lateral inclination positions of the engine;

Fig.2

schematically shows an AA cut of the engine of the Fig.1 when not inclined;

Fig.3

shows schematically front sections of a motor not forming part of the invention, and according to several lateral inclination positions of the engine;

Fig.4

schematically shows a BB cut of the engine of the Fig.3 when not inclined;

Fig.5, 6A and 6B

schematically show front sections of a motor not forming part of the invention the engine is not inclined;

Fig. 7A and 7B

schematically show frontal sections of an engine according to particular embodiments of the invention when the engine is not inclined;

Fig.8

schematically shows a rear view of a motorcycle equipped with a motor according to the invention.

The drawings of the figures are not to scale. Generally, similar elements are denoted by similar references in the figures.

Detailed description of particular embodiments

The Fig.1 shows schematically front sections of a motor (1) known and shown in several lateral inclination positions of the engine. This engine comprises, in known manner, a piston (2), a connecting rod (3), a crankshaft (4) having an axis of rotation (5), a housing (6) containing oil (7), and a spoon (8) connected to the connecting rod (3) for drawing oil into the housing (3) and for driving and throwing the oil to parts of the engine to be lubricated. When the crankshaft rotates, a distal end (9) of the spoon (8) describes an orbit lying in an orbital plane (10). Said orbital plane (10) is perpendicular to the axis of rotation (5) of the crankshaft (4).

In this figure, the motor (1) is shown as mounted on a motorcycle which we see the wheel (15). It is noted that when the motor (the motorcycle) is inclined to the left or to the right, the level of oil in the housing (6) is hollow, which has the effect of reducing the height of available oil at level of the spoon (8). Depending on the driving circumstances, this oil level can descend below the distal end (9) of the spoon (8), so that the engine will no longer be lubricated in these circumstances.

The Fig.2 schematically shows an "AA" cut of the engine of the Fig.1 when not inclined;

The Fig.3 shows schematically front sections of a motor not forming part of the invention, and according to several lateral inclination positions of said motor. It is a motor (1) as represented in Fig. 1 and further comprising two walls (11a, 11b) disposed within the housing (7) and respectively on either side of the orbital plane (10) of the spoon (8).

Each wall (11a, 11b) extends substantially transversely to the axis (5) of the crankshaft (4) and rises, starting from a lower portion of the housing (6), to the top of a distal end (9) of the spoon (8) when said spoon is in a lowest position (= when the piston (2) is at its bottom dead point). These walls are arranged to form an obstacle to a lateral movement of the oil (7) of the housing. Several forms and arrangements are therefore possible for the walls. Preferably, the walls are plates substantially flat, for example metal plates.

As we see on the left and the right part of the Fig. 3 , the presence of these walls inside the housing will have the effect of preventing the oil from moving too laterally when the motorcycle tilts to take turns. Thus, the oil level in the orbital plane (10) of the distal portion (9) of the spoon will be greater than it would be in the absence of said walls, which allows the spoon (8) can continue to draw oil and lubricate the engine.

The Fig.4 schematically shows a section BB of the engine (1) of the Fig.3 when not inclined. It shows the walls (11a, 11b) which, in this example, are two metal plates fixed to the housing (6) by fixing means. There is a clearance between the lower (13) and lateral edges of each plate and respectively the lower and lateral walls of the casing, thus allowing the oil to be distributed again uniformly in the casing when the motor returns to its normal position ( orbital plane (10) vertical). Preferably, said clearance is between 1 mm and 2 cm.

The walls (11a, 11b) may be parts attached to the housing, which makes it easy to transform existing engines and not having such walls. Alternatively, the walls (11a, 11b) are an integral part of the housing (example: casing having the walls and cast or formed in one piece).

The Fig. 5 shows a version of the engine not forming part of the invention. Here, each wall (11a, 11b) forms a partition, that is to say that it is sealingly connected to the housing in its lower and lateral part, an upper edge (12) of each wall remaining free.

Said upper edge (12) has a height (H1) which is less than a recommended minimum oil level (H2) in the housing. The recommended minimum oil level (H2) is a typical data of an engine, well known to those skilled in the art, and which ensures a minimum oil volume in the crankcase. This makes it possible to obtain oil that has passed over a wall during a turn, would return to its original location during a turn in the opposite direction or when the motorcycle returns to a vertical position. .

According to this version, the height (H1) of the upper edge (12) of each wall will thus be between the height of the distal end (9) of the spoon when the cylinder (2) is at its bottom dead point and the level of recommended minimum oil (H2) in the crankcase.

The Fig. 6A shows another version of the engine not part of the invention. This is the same engine as the one shown in Fig.5 except that the walls (11a, 11b) are arranged in such a way that an upper edge (12) of each wall is closer to the orbital plane (10) of the spoon than to the corresponding side wall of the housing (6). Preferably, the upper edge (12) of each wall is a distance from the orbital plane (10) which is less than 20% of the distance between said orbital plane (10) and the corresponding side wall of the housing.

The Fig. 6B shows a variant of the engine of the Fig. 6A in which the walls (11a, 11b) do not form partitions but are spaced apart from the housings. Preferably, said distance is between 1 mm and 2 cm. In this case, the upper edge (12) of a wall may (but must not) be at a height (H1) which is greater than the recommended minimum oil level (H2) in the housing.

According to the invention, an upper edge (12) of a wall (11a, 11b) is closer to the orbital plane (10) of the spoon than a lower edge (13) of said wall.

An exemplary embodiment is illustrated in the Fig. 7a . This is the same engine as the one shown in fig.6a , except that the plates (11a, 11b) are here arranged obliquely. This has the advantage that, during a left turn for example, the oil will pass more easily over the right wall (11b) and less easily over the left wall (11a), as a result of which oil will tend to accumulate more in the central region between the two plates, which makes it possible to have an oil level higher in the orbital plane (10) of the spoon. The same advantage is of course obtained in a right turn.

The angle formed by a plate (11a, 11b) with the bottom wall of the casing is preferably between 20 ° and 90 °, more preferably between 30 ° and 60 °, even more preferably between 40 ° and 40 °. 50 °.

Another advantage of positioning the walls obliquely is to reduce the bulk of the walls while maintaining a sufficient volume of oil between the two walls.

The Fig. 7b shows an alternative embodiment of the engine of the Fig. 7a and wherein the walls (11a, 11b) are spaced apart from the housing. In this case, the upper edge (12) of a wall may (but must not) be at a height (H1) which is greater than the recommended minimum oil level (H2) in the housing.

The invention also relates to a motorcycle comprising a motor (1) as described above. The Fig.8 schematically shows a rear view of a motorcycle equipped with a motor according to the invention. It shows how the axis (5) of the crankshaft of the engine (1) is positioned relative to the motorcycle.

"Motorcycle" means any motorized vehicle designed to tilt - left or right - when the vehicle is in a corner. The invention is therefore not limited to two-wheeled motor vehicles or engines for two-wheeled vehicles.

The embodiments described above relate to a single-cylinder engine. It will be obvious to a person skilled in the art that an engine according to the invention may also comprise several cylinders with several connecting rods, each connecting rod being or not being provided with a spoon (8), in which case the walls (11) for example between the orbital planes of the spoons or between the orbital plane of a spoon and a side wall of the housing.

In the examples illustrated above, the cylinder is vertical, but the invention also relates to any other arrangement of (the) cylinder (s), such as a horizontal cylinder or oblique ("V") for example.

Preferably, an engine according to the invention does not include an oil pump to lubricate the engine.

The present invention has been described in relation to specific embodiments, which have a purely illustrative value and should not be considered as limiting. In general, it will be apparent to those skilled in the art that the present invention is not limited to the examples illustrated and / or described above and its scope is limited to the claims. .

The presence of reference numbers in the drawings can not be considered as limiting, even when these numbers are indicated in the claims.

The use of the verbs "to understand", "to include", "to include", or any other variant, as well as their conjugations, can in no way exclude the presence of elements other than those mentioned.

The use of the definite article "a" to introduce an element does not exclude the presence of a plurality of these elements.

• Moteur à combustion interne (1) à quatre temps pour moto comportant au moins un cylindre muni d'un piston (2), un vilebrequin (4) horizontal, une bielle (3) reliant le piston au vilebrequin, et un carter (6) à huile (7) sous le vilebrequin. Le moteur inclut un système de lubrification par barbotage comportant une cuiller (8) fixée à la bielle et apte, en fonctionnement, à puiser de l'huile (7) dans le carter pour l'amener vers des pièces moteur à lubrifier, ainsi qu'au moins une paroi (11a, 11b) interne au carter et disposée transversalement par rapport à un axe de rotation (5) du vilebrequin (4). Chaque paroi (11a, 11b) forme un obstacle au déplacement de l'huile dans le carter lorsque le moteur est soumis à des mouvements tels que par exemple des mouvements de balancier autour d'un axe situé en dehors du moteur. Ceci à pour effet de maintenir un niveau d'huile suffisant dans le carter dans un plan orbital (10) d'une extrémité distale (9) de la cuiller et ainsi d'assurer une meilleure continuité de la lubrification lorsque le moteur est soumis auxdits mouvements.

In summary, the invention can be described as follows:

• Four-stroke internal combustion engine (1) for a motorcycle comprising at least one cylinder provided with a piston (2), a crankshaft (4) horizontal, a connecting rod (3) connecting the piston to the crankshaft, and a housing (6) oil (7) under the crankshaft. The engine includes a splash lubrication system having a spoon (8) attached to the connecting rod and operable to draw oil (7) into the crankcase for delivery to engine parts to be lubricated, as well as at least one wall (11a, 11b) internal to the housing and arranged transversely with respect to an axis of rotation (5) of the crankshaft (4). Each wall (11a, 11b) forms an obstacle to the displacement of the oil in the casing when the motor is subjected to movements such as for example pendulum movements about an axis located outside the engine. This has the effect of maintaining a sufficient oil level in the housing in an orbital plane (10) of a distal end (9) of the spoon and thus to ensure a better continuity of the lubrication when the engine is subjected to said movements.

Claims (4)

1. Four-stroke internal combustion engine (1) for motorbike, comprising at least one piston (2) cooperating with at least one connecting rod (3) and a crankshaft (4) for driving the crankshaft into rotation according to a horizontal crankshaft axis (5), an oil pan (6) located under the crankshaft, and a splashing lubrication system comprising a spoon (8) interdependent from the connecting rod (3) and extending in a direction towards the oil pan (6), the oil pan comprises - inside its volume and on both sides of an orbital plan (10) of the spoon - at least one wall (11a, 11b) forming an obstacle to a movement of the oil of the oil pan, each wall extending substantially transversely to the crankshaft axis (5) and rising from a basis of the oil pan to above a distal end (9) of the spoon (8) when the spoon is in its lowest position, characterized in that, for each wall (11a, 11b), a higher edge (12) of the wall (11a, 11b) is closer to the orbital plan (10) of the spoon than a lower edge (13) of said wall, and in that each wall (11a, 11b) is an obliquely arranged plate;
2. Engine according to claim 1, characterized in that each wall (11a, 11b) forms a partition in the oil pan and in that each wall has a height (H1) which is lower than a minimum recommended oil level (H2) in the oil pan (6);
3. Engine according to claim 1 or 2, characterized in that a higher edge (12) of each wall is closer to the orbital plan (10) of the spoon than to the corresponding side wall of the oil pan;
4. Motorbike comprising an engine (1) according to any of the preceding claims.

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