DE19755687A1 - Two-stroke gasoline engine with separate lubrication - Google Patents

Abstract

The invention relates to a two stroke spark ignition engine with separate lubrication, especially those used in hand-held working tools with fast running motors, wherein the piston (10) has recesses to receive the motor oil. Said motor is appropriately lubricated between the piston and the cylinder wall and exhibits reduced oil consumption without impairing the moving parts in the crankcase. The piston (10) has two opposite recesses (17, 18) beneath the piston head (19) running in a straight line towards the lower edge (21) of the piston (10). A peripheral slot (16) is provided in the area of the recesses (17, 18) in the piston skirt (15), said slot being interrupted by the recesses (17, 18). At least two holes (24, 25) are provided in the cylinder base (23), which are lubricated by the slot (16) in the lower dead center area and through which the lubricating oil is fed to the cylinder by appropriate devices.

Description

The invention relates to two-stroke gasoline engine with separate lubrication, especially for hand-held tools with high-speed engines in which the piston vertie has to hold engine oil.

There is always a need for internal combustion engines Maneuverability of the lubrication of the piston and the mov parts to prevent engine damage. The lubrication the two-stroke engine is still predominantly over added lubricating oil to the fuel. For  Can reduce the proportion of oil in the fuel mixture separate lubrication can also be provided. Known are methods in which the lubricating oil over the inlet box nal / crank mechanism is fed to the engine or directly to the moving parts of the engine is guided.

In the latter solution, for. B. the piston over ent speaking holes in the cylinder wall to lubricating oil guided. There, e.g. B. due to the design with Linkage of a connecting rod to the piston, the pressure of the Piston varies on the cylinder wall, so is the Be may differ in the lubricating oil on the cylinder wall. To always ensure lubrication, the Zu drove on lubricating oil set according to the highest need, d. H. that there is more lubrication in the many places than necessary, so that a higher oil consumption results animals as actually necessary. To solve this problem sen, it is known for. B. from DE 7 53 580, the Lubrication holes in the cylinder wall in the area of the high pressure load. By ver tied reduction in the oil content in the fuel disadvantageously also the lubrication of the movable Parts in the crankcase reduced, which are inadequate can be appropriate.

It is from the US Re. 35,551 also known in the col shirt of pistons of a four-stroke engine notches for Improve lubrication at top dead center bring. These notches are reached via corresponding ones Bores in the cylinder wall lubricating oil that in the Notches remain and during the piston stroke to the Schmie tion of the particularly pressurized areas of the Zy linderwand serves.

It is therefore an object of the invention to provide a two-stroke Ot To create tomotor with separate lubrication, the two between the piston and the cylinder wall  Lubrication and thus a reduced oil consumption points without the lubrication of the moving parts in Crankcase is deteriorated.

This object is achieved by the features of claim 1 solved.

For this purpose, a two-stroke engine is provided according to the invention To create tomotor with separate lubrication, in particular for hand-held tools with high-speed Engines, whose pistons, the two opposite Has recesses, via a groove in the piston skirt ver adds. The groove is interrupted by the recoveries revolving around the piston.

The retractions run straight towards the cure belgehäuses, the surfaces thus formed perpendicular to the axis on which the connecting rod on the Crank is articulated, are located. The recoveries extend to the edge of the piston leading to the Crankcase points.

The piston of the engine according to the invention sweeps one or during operation in bottom dead center several holes in the cylinder base for Lubricating oil that is continuously pumped, whereby the groove fills with lubricating oil. When connecting the groove takes the lifting movement to the top dead center Lubricating oil with and lubricates between the piston and cylinder wall in the area of increased stress, whereby also Lubricating oil emerges from the side of the groove, which also the less loaded cylinder wall is lubricated, the is applied during the downward movement of the piston. The superfluous is stripped off and reaches the cure Bel housing for lubricating the parts inside.  

The piston is located above the bore in the cylinder the foot becomes the continuously extracted oil in the cure swirled housing and also serves for smacking Main, connecting rod and piston pin bearings.

The groove for receiving the lubricating oil can differ Lich designed. So the bottom of the groove can wink lig or rounded be designed so that the lubricating oil is held differently in the groove. This Effect can be varied by grooving or the like. be introduced at the bottom of the groove.

If necessary, holes can be made from this groove lead right to the upper connecting rod bearing (not shown), in order to consequently reduce the bearing demands adorn.

The inventive design of the two-stroke Gasoline engine all parts are lubricated in such a way that there is no surplus which remains ineffective and would increase pollutant emissions. It is therefore before partly the oil consumption compared to the state of the Technology significantly reduced, so that in particular the resulting exhaust gases are low in pollutants. It is appropriate lubrication for all parts of the engine guaranteed.

By supplying the oil to the person as required Consumers (lubrication points), an additional sere heat dissipation from "friction points" at the same time reduced wear due to lower friction enough.

Further advantageous embodiments are in the Un marked claims.

The invention will now be described with reference to drawings explained in more detail. It shows  

Fig. 1 in a side view of a piston of he inventive two-stroke gasoline engine,

Fig. 2 in a sectional side Detailan view of a piston of a two-stroke gasoline engine according to the invention, only its cylinder wall deryl is Darge in a highly schematic form, and

Fig. 3 in a sectional side Detailan view analogous to FIG. 2, a two-stroke gasoline engine in a different working state.

The piston 10 of the two-stroke Ottomo tors according to the invention, which is shown in fragments only in the form of the cylinder wall 11 , is movable in the cylinder 12 GE. The piston 10 has, apart from the grooves 13 , 14 for receiving rings, not shown, for sealing and stripping of the engine oil in the piston skirt 15 also a groove 16 , the head by two against opposing indentations 17 , 18 below the piston 19 and the aforementioned Grooves 13 , 14 is interrupted. The retractions 17 , 18 extend to the lower edge 21 of the piston skirt 15 , the conditions 17 , 18 at right angles to the axis 20 , via which the connecting rod 22 is articulated on the piston 10 , are aligned. In the cylinder wall 11 in the region of the Zylin derfußes 23 holes 24 , 25 are made through which lubrication oil is continuously conveyed via a device, not shown. If the piston 10 is at bottom dead center ( FIG. 2), the groove 16 is located directly in front of the bores 24 , 25 , so that the groove 16 fills with lubricating oil. In the subsequent upward movement ( Fig. 3), the heavily loaded areas of the cylinder wall 11 are lubricated by the lubricating oil. While the piston 10 is above the holes 24 , 25 , the lubricating oil is swirled in the crankcase, not shown, and is used to lubricate the moving parts. Lubricating oil flows out of the laterally open groove 16 during the upward movement and lubricates the areas above the recesses 17 , 18 and the cylinder wall 11 sufficiently in this area.

Reference list

10th

piston

11

Cylinder wall

12th

cylinder

13

Groove

14

Groove

15

Piston shirt

16

Groove

17th

Confiscation

18th

Confiscation

19th

Piston head

20th

axis

21

edge

22

connecting rod

23

Cylinder base

24th

drilling

25th

drilling

Claims (5)

1. Two-stroke gasoline engine with separate lubrication, in particular for hand-held tools with fast-running engines in which the piston ( 10 ) has recesses for receiving engine oil, characterized in that the piston ( 10 ) has two opposing recesses ( 17 , 18 ) below the piston head ( 19 ), which extend straight to the lower edge ( 21 ) of the piston ( 10 ), with a circumferential groove ( 16 ) being provided in the area of the recesses ( 17 , 18 ) in the piston skirt ( 15 ) is interrupted by the recesses ( 17 , 18 ), and that in the cylinder base ( 23 ) at least two bores ( 24 , 25 ) are made, which are swept in the area of bottom dead center by the groove ( 16 ) and by the lubricating oil in the cylinder ( 12 ) is funded through appropriate institutions. 2. Two-stroke gasoline engine according to claim 1, characterized in that the two-stroke gasoline engine has facilities for the continuous delivery of lubricating oil to the Boh stanchions ( 24 , 25 ) in the cylinder base ( 23 ). 3. Two-stroke gasoline engine according to claim 1 or 2, characterized in that the surfaces formed by the recesses ( 17 , 18 ) are arranged substantially at right angles to the axis ( 20 ) on which the connecting rod ( 22 ) on the piston ( 10 ) is articulated. 4. Two-stroke gasoline engine according to one of claims 1 to 3, characterized in that the groove ( 16 ) is angled or rounded and / or that on the bottom of the groove ( 16 ) grooves or the like are introduced. 5. Two-stroke gasoline engine according to one of claims 1, 2 or 4 characterized in that a or several cross holes to the upper connecting rod eye are executed.