WO2012059357A1

WO2012059357A1 - Motorcycle engine

Info

Publication number: WO2012059357A1
Application number: PCT/EP2011/068578
Authority: WO
Inventors: Dirk Steenwerkers
Original assignee: Steenfun
Priority date: 2010-11-04
Filing date: 2011-10-24
Publication date: 2012-05-10
Also published as: ES2428940T3; DK2450536T3; EP2450536A1; EP2450536B1

Abstract

The invention relates to a four-stroke internal combustion engine (1) for a motorcycle, comprising at least one cylinder provided with a piston (2), a horizontal crankshaft (4), a connecting rod (3) connecting the piston to the crankshaft, and an oil (7) pan (6) arranged below the crankshaft. The engine includes a splash-lubrication system comprising a scoop (8) attached to the connecting rod and capable, during operation, of drawing oil (7) from the oil pan in order to convey the oil to the engine parts to be lubricated, as well as at least one inner wall (11a, 11b) of the oil pan arranged transversely with respect to an axis of rotation (5) of the crankshaft (4). Each wall (11a, 11b) is at least partially angled inwardly and forms an obstacle to the movement of the oil in the pan when the engine is subjected to movements such as rocking movements about an axis located outside the engine. This has the effect of maintaining a sufficient level of oil in the pan in an orbital plane (10) of a distal end (9) of the scoop, and thus of ensuring better continuity of lubrication when the engine is subjected to said movements.

Description

MOTOR FOR MOTORCYCLE

Field of the Invention The invention relates to a motorcycle four-stroke engine utilizing bubble 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 the case, for example, with the engines fitted to the Henderson Four bikes produced by the American firm Henderson.

Motorcycle Co from the year 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, splash 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, this is no longer the

crankshaft which buzzes in the oil of the crankcase, 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 oil to draw from the crankcase. oil and drive and project this oil onto the engine parts requiring lubrication.

For example, such a motorcycle motor is known from 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 tips

successively the motorcycle on both sides 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 Publication No. 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. . For this purpose, the engine according to the invention is

characterized in that, for each wall, an upper edge of the wall is closer to the orbital plane of the spoon than a lower edge of said wall. When an engine according to the invention is mounted

transversely on a motorcycle to propel it and when the motorcycle changes inclination with respect to a vertical plane - which is for example the case when the motorcycle enters or turns out of a turn or when a turn changes bends or when the speed of the motorcycle varies during a turn - the walls, thus tilted inwards, will stop or better prevent the oil from moving sideways relative to the orbital plane of the spoon, thus ensuring a greater oil height in said orbital plane than in the absence of such walls or with non-inclined walls inwardly. 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 larger than

the absence of such walls or with walls not inclined inwards.

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 housing. 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 housing 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 housing when the engine is inclined

laterally, will be distributed again

substantially equal between the compartments when the motor will reverse its direction of inclination (left / right or right / left).

BRIEF DESCRIPTION OF THE DRAWINGS These aspects as well as other aspects of the invention will be clarified in the detailed description of particular embodiments of the invention, reference being made to the drawings of the figures, in which: Fig. 1 shows schematically front sections of a known engine and several lateral inclination positions of the engine;

Fig.2 shows schematically a section AA of the engine of Fig.l when not inclined;

Fig.3 schematically shows frontal sections

motor according to the invention, and according to several lateral inclination positions of the engine;

Fig.4 schematically shows a BB section of the engine of Fig.3 when not inclined;

Figs.5, 6A, 6B schematically show sections

front end of an engine according to particular embodiments of the invention when the engine is not inclined;

Fig.7 schematically shows a rear view

a motorcycle equipped with an engine 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 FIG. 1 schematically shows front sections of a motor (1) known and represented according to several

side tilt 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 in the crankcase (3) and to drive and project this 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). According to

circumstances of running, this oil height can descend below the distal end (9) of the spoon (8), so that the engine will no longer be lubricated in these circumstances.

Fig.2 shows schematically a section "AA" of the engine of Fig.l when not inclined;

3 diagrammatically shows frontal sections of an engine according to the invention, and in several lateral inclination positions of said engine. It is a motor (1) as shown in FIG. 1, and further comprising two walls (11a, 11b) disposed inside 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, 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 thus arranged to form an obstacle to lateral movement of the oil (7) of the housing.

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

Each wall (11a, 11b) is thus arranged

substantially obliquely and substantially inwardly inclined.

Such a configuration 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 the oil will tend to more

accumulate in the central region between the two plates, which allows 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 wall (11a, 11b) (or the part of a wall which is inclined towards the orbital plane) with the wall of the bottom of the housing is preferably between 20 ° and 90 °, more preferably between 30 ° and 60 °, even more preferably between 40 ° and 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. Several forms and arrangements are therefore possible for the walls, including for example walls

partially oblique and / or at least

partially concave (seen from the spoon). The important thing is that at least a substantial part of a wall is inclined towards the orbital plane (10) of the spoon.

Preferably, the walls are plates

substantially flat, eg plates

metal.

Fig.4 schematically shows a section BB of the motor (1) of Fig.3 when it is not inclined. It shows the walls (11a, 11b) which, in this example, are two metal plates fixed to the housing (6) by means of

fixation. There is a clearance between the lower (13) and lateral edges of each plate and respectively the lower and lateral walls of the housing, thus allowing the oil to be distributed again uniformly in the housing when the engine returns to its normal position.

(vertical orbital plane (10)). Preferably, said clearance is between 1 mm and 2 cm.

The walls (11a, 11b) can be parts

to the housing, which allows for easy

transform existing engines and do not have such walls. Alternatively, the walls (11a, 11b) form an integral part of the housing (example: casing having the walls and cast or formed in one piece). Figs. 5, 6A, 6B schematically show frontal sections of an engine according to particular embodiments of the invention. Fig. 5 shows a preferred version of the engine according to the invention. Here, each wall (11a, 11b) forms a

partition, that is to say it is connected in a sealed manner 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 preferred version, the height (Hl) of the upper edge (12) of each wall will be between the height of the distal end (9) of the spoon when the cylinder (2) is at its bottom dead point and the recommended minimum oil level (H2) in the crankcase.

Fig. 6A shows an even more preferred version of the engine according to the invention. This is the same motor as that shown in Fig.5, except that the walls (11a, 11b) are arranged here so that an upper edge (12) of each wall is closer to the orbital plane (10). ) of the spoon as 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. Fig. 6B shows a variant of the engine of FIG. 6A, in which the walls (11a, 11b) do not form partitions but are placed at a distance 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.

The invention also relates to a motorcycle comprising a motor (1) as described above. Fig.7 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. The invention includes each of the novel features as well as all their combinations.

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",

"Comprise", or any other variant, and 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.

In summary, the invention can also be described as follows: an internal combustion engine (1) four-stroke motorcycle comprising at least one cylinder provided with a piston (2), a crankshaft (4) horizontal, a rod ( 3) connecting the piston to the crankshaft, and a crankcase (6) to oil (7) under the crankshaft. The engine includes a system of splash lubrication comprising a spoon (8) fixed to the connecting rod and operable to draw oil (7) into the housing to bring it to engine parts to be lubricated, and at least one wall ( 11a, 11b) internal to the housing and arranged transversely to an axis of rotation (5) of the crankshaft (4). Each wall (11a, 11b) is at least partially inclined towards

inside and forms an obstacle to the displacement of the oil in the crankcase when the engine is subjected to

movements such as for example pendulum movements around 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 lubrication when the engine is subjected to said movements.

Claims

1. Motor (1) four-stroke internal combustion engine for motorcycle comprising at least one piston (2) cooperating with at least one connecting rod (3) and a crankshaft (4) for rotating the crankshaft along an axis (5) of crankshaft horizontal, a casing (6) oil bath under the

crankshaft, and a splash lubrication system comprising a spoon (8) integral with the connecting rod (3) and extending towards the housing (6), the housing comprises, within its volume and on the part and other than an orbital plane (10) of the spoon, at least one wall (11a, 11b) obstructing movement of the crankcase oil, each wall extending substantially transversely to the axis (5) ) of the crankshaft and rising, from a lower part of the housing, to the top of a distal end (9) of the spoon (8) when said spoon is in a lowest position, characterized in that 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;

2. Engine according to claim 1, characterized in that each wall (11a, 11b) forms a partition in the housing and in that each wall has a height (H1) less than a recommended minimum oil level (H2) in the housing (6);

3. Motor according to claim 1 or 2, characterized in that an upper edge (12) of each wall is closer to the orbital plane (10) of the spoon than the corresponding side wall of the housing (6);

4. Motorcycle comprising a motor (1) according to any one of the preceding claims.