WO2013170947A1

WO2013170947A1 - Piston of an internal combustion engine

Info

Publication number: WO2013170947A1
Application number: PCT/EP2013/001406
Authority: WO
Inventors: Talat Shaer; Hubert Pelzel
Original assignee: Man Diesel & Turbo Se
Priority date: 2012-05-15
Filing date: 2013-05-14
Publication date: 2013-11-21
Also published as: JP5964497B2; KR20150013770A; KR101687090B1; DE102012208090B4; FI20145895A; CN104302902A; FI126961B; DE102012208090A1; JP2015514182A; CN104302902B

Abstract

A piston of an internal combustion engine, having a piston upper part (10) and a piston lower part (11), having a piston pin (12) which is mounted in the piston lower part (11) and which serves for connecting the piston to a connecting rod (13) of the internal combustion engine, having an inner cooling chamber (15), formed between the piston upper part (10) and the piston lower part (11), for cooling oil for cooling the piston, said inner cooling chamber being connected via at least one transfer bore (17) to an outer cooling chamber (16) formed between the piston upper part (10) and a piston lower part (11), and having a single-piece slide shoe (19) which is movably mounted in the piston lower part (11) and which is forced by means of a spring element (20) against a connecting rod head (14) of the connecting rod (13) and which serves for transferring cooling oil, which has been conducted through a bore (18) in the connecting rod (13), into the inner cooling chamber (15), wherein a guide surface (21) for the single-piece slide shoe (19) is formed between the single-piece slide shoe (19) and the piston lower part (11), and wherein, as viewed in the axial direction of the piston and slide shoe, the spring element (20) extends, at least in sections, parallel to the guide surface (21) for the single-piece slide shoe (19).

Description

Piston of an internal combustion engine

The invention relates to a piston of an internal combustion engine according to the preamble of claim 1. Furthermore, the invention relates to a sliding block for such a piston of an internal combustion engine according to the preamble of claim 8.

From DE 35 18 721 C2, a piston of an internal combustion engine is known which comprises a piston upper part and a lower piston part, which are preferably screwed together. In the piston lower part a piston pin is mounted, wherein the piston pin is used to connect the piston to a connecting rod of the internal combustion engine. The piston according to DE 35 18 721 C2 is oil-cooled, wherein on the one hand an inner cooling space for cooling oil and on the other hand an outer cooling space for cooling oil is formed between the piston upper part and the piston lower part, and wherein the inner cooling space is connected to the outer cooling space via at least one Überleitbohrung. In order to introduce cooling oil into the inner cooling space, a feed bore for cooling oil is integrated into the connecting rod according to this prior art, wherein the cooling oil, starting from the connecting rod in the inner cooling space can be converted using a two-piece cooling oil supply. A first, neck-like part of the two-part cooling oil guide sleeve is fixed immovably in the lower piston part of the piston according to DE 35 18 721 C2. With this stationary, neck-like part of the two-part cooling oil guide sleeve a funnel-like, movable part of the cooling oil guide sleeve cooperates such that a spring element which acts between the two parts of the two-part cooling oil guide sleeve, the funnel-like part of the same resiliently presses in sliding contact against a connecting rod of the connecting rod. The use of such multi-part Kühlölführhülsen for transferring the cooling oil, starting from the bore in the connecting rod in the inner cooling chamber is disadvantageous because the assembly of such multi-part Kühlölführhülsen is possible only with great effort.

CONFIRMATION COPY From practice, it is already known to replace the known from DE 35 18 721 C2, multi-part Kühlölführhülsen, namely by one-piece sliding shoes. 1 shows a detail of a piston of an internal combustion engine in the region of an inner cooling space 3 formed between a piston upper part 1 and a piston lower part 2, wherein a one-piece sliding shoe 4 is movably mounted in the piston lower part 2. This slide shoe 4 has a neck-like end 5 and a funnel-like end 6, the slide shoe 4 serving to transfer the cooling oil starting from the connecting rod, not shown in FIG. 1, into the inner cooling space 3. For this purpose, a bore 7 is introduced into the sliding block 4, which penetrates both the neck-like end 5 and the funnel-like end 6 of the sliding shoe 7 and widens like a funnel in the funnel-like end 6. It can further be seen from FIG. 1 that a guide surface 8 for the sliding shoe 4 is formed between the sliding shoe 4 and the piston lower part 2, namely in the region of the neck-like end 5 of the sliding shoe 4 adjacent to the funnel-like end 6 thereof. A spring element 9, which can be pressed the sliding shoe 4 in a connecting rod, not shown in Fig. 1, is supported on the one hand on the shoe 4 and on the other hand on the lower housing part 2, wherein seen in the axial direction of the piston or the shoe 4 this spring element 9 in series to the guide surface 8 is arranged.

In such pistons for internal combustion engines, the so-called compression height is a characteristic parameter, wherein the compression height corresponds to the distance between the axis of the piston pin and an upper edge of the piston. The overall height of an internal combustion engine is determined inter alia by this compression height of the or each piston of the internal combustion engine. Another characteristic parameter of a piston of an internal combustion engine, which has an influence on the overall height of the internal combustion engine, is a so-called piston-chamber depth of a piston recess formed in the region of the piston upper part. Relatively deep piston recesses can improve the combustion in the cylinder of the respective internal combustion engine in which the respective piston is used. The deeper a piston recess is made, the higher, however, the compression height and thus height of the engine. Proceeding from this, the present invention has the object to provide a novel piston of an internal combustion engine and a novel sliding block for such a piston.

This object is achieved by a piston according to claim 1. According to the invention, the spring element extends in the axial direction of the piston or sliding shoe at least in sections parallel to the guide surface for the one-piece sliding shoe.

With the invention, it is possible to perform deeper piston recesses at a constant compression height of a piston or to reduce the compression height of the respective piston at the same piston depth.

According to an advantageous embodiment of the invention, the guide surface for the one-piece sliding shoe surrounds the spring element radially outside at least in sections. Such a configuration allows a particularly advantageous embodiment of the one-piece shoe and thus a particularly advantageous effect on the compression height of the piston and / or the piston bowl depth.

Preferably, the one-piece shoe has a neck-like end and a funnel-like end, wherein the funnel-like end is pressed by the spring element against the connecting rod of the connecting rod, and wherein starting from the funnel-like end at least in sections radially outward around the neck-like end a projection with Radial distance to the neck-like end extends. The guide surface for the sliding block is formed between the projection and the piston lower part. The spring element extends into a space formed between the projection and the neck-like end. This embodiment of the one-piece sliding block of the piston is particularly preferred. The sliding shoe according to the invention is defined in claim 8.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:

Fig. 1: a section of a known from the prior art

Piston in the region of a one-piece sliding shoe;

2 shows a first section of a piston according to the invention in the region of a one-piece sliding shoe;

3 shows a second detail of a piston according to the invention in FIG

Area of the one-piece sliding shoe; and

Fig. 4: the shoe of Fig. 2 in solo view.

The present invention relates to an oil-cooled piston of an internal combustion engine, in particular designed as a diesel engine or gas engine or diesel-gas engine engine, such as a marine diesel engine. Such a piston is also referred to as a plunger.

FIGS. 2 and 3 each show a detail of a piston according to the invention of an internal combustion engine, wherein the piston comprises a piston upper part 10 and a piston lower part 11. The upper piston part 10 and the lower piston part 11 are preferably made of a light metal, steel or nodular cast iron. The piston upper part 10 and the lower piston part 11 are supported on one another and are preferably fastened to one another via fastening means designed as expansion screws. In a bore of the piston lower part 11, a piston pin 12 is mounted, wherein the piston pin 12 of the connection of the piston to a connecting rod 13 of the internal combustion engine is used. Of the connecting rod 13, a so-called Pleuelkopf 14 is shown in Fig. 2.

Between the upper piston part 10 and the lower piston part 11, on the one hand, an inner cooling chamber 15 and, on the other hand, an outer cooling chamber 16 for cooling oil are formed, wherein the inner cooling chamber 15 is connected to the outer cooling chamber 16 according to FIG. 2 via transfer bores 17. The cooling oil is the inner cooling chamber 15 via a bore 18 can be fed, which extends through the connecting rod 13 and also by the connecting rod 14, wherein the cooling oil from the connecting rod 13 in the inner cooling chamber 15 by means of a shoe 19 can be transferred, in the lower piston part 11 is movably mounted. The sliding shoe 19 movably mounted in the lower piston part 11 is designed as a one-piece sliding shoe 19 and is pressed against the connecting rod 14 of the connecting rod 13 by a spring element 20 for sealing purposes. Between the one-piece slide shoe 19 and the lower piston part 11, a guide surface 21 is formed, which serves to guide the piston base 11 movably mounted, one-piece slide shoe 19.

According to the invention, the spring element 20 extends in the axial direction of the piston and the sliding block 19 at least in sections parallel to the guide surface 21 for the one-piece sliding shoe 19. This can be compared to the prior art, the overall height of the one-piece shoe reduced. A reduced overall height of the sliding shoe 19 can be used to reduce the so-called compression height of the piston, ie the distance between the axis of the piston pin 12 and an upper edge of the piston. Furthermore, a depth of a piston recess 22, which is provided by the piston upper part 10, can thereby be increased at a constant compression height in order to positively influence the combustion of the internal combustion engine. The guide surface 21 for the one-piece sliding shoe 19 surrounds, at least in sections, the spring element 20 radially outward. Accordingly, the spring element 20 is positioned radially within the guide surface 21 for the sliding shoe 19 as viewed in the radial direction of the piston or of the sliding shoe 19.

As already stated, the sliding shoe 19 is used to transfer cooling oil starting from the connecting rod 13 into the inner cooling space 15, with a bore 22 extending in the axial direction through the sliding shoe 19 for this purpose.

The one-piece slide shoe 19 has a first, neck-like end 23 and a second funnel-like end 24, wherein the funnel-like end 24 of the slide shoe 19 is pressed by the spring element 20 sealingly against the connecting rod 14 of the connecting rod 13. Starting from the second, funnel-like end 24 extends at least partially radially outward around the neck-like end 23 around a projection 25 having a radial distance from the neck-like end 23, so that between the radially inner, neck-like end 23 and the radially outer projection 25th a free space 26 is formed. The spring element 20, which is supported on the one hand on the one-piece slide shoe 19 and on the other hand on the piston lower part 11, extends into this free space 26. The guide surface 21 for the sliding shoe 19 is formed between this projection 25 and the lower piston part 11.

The present invention further relates to the shown in Fig. 4 in solo view shoe 19 for a piston of an internal combustion engine. To avoid unnecessary repetition, reference is made to the above statements with regard to details of the one-piece sliding shoe 9.

As best seen in Fig. 3, engages the neck-like end 23 of the one-piece shoe 19, a retaining ring 27, with which the shoe 19 is also held on the piston lower part 11 when the connecting rod 13 is disassembled during assembly or disassembly of the piston , With the invention, with a constant compression height of a piston, a piston recess 22 can be made deeper. Furthermore, with the same depth of the piston recess 22, the compression height of the piston can be reduced. In addition, both effects can be used combinatorial, so on the one hand an increase in the piston bowl depth and on the other hand, a reduction in the compression height of the piston.

LIST OF REFERENCE NUMBERS

1 piston upper part

2 piston lower part

3 refrigerator

4 sliding shoe

5 end

6 end

7 hole

8 guide surface

9 spring element

10 piston upper part

11 piston lower part

12 piston pins

13 connecting rod

14 connecting rod head

15 refrigerator

16 refrigerator

17 transfer hole

18 hole

19 shoe

20 spring element

21 guide surface

22 bore

23 end

24 end

25 advantage

26 free space

27 circlip

Claims

claims

Piston of an internal combustion engine, with a piston upper part (10) and a piston lower part (11), with a piston pin (12) which is mounted in the piston lower part (11) and the connection of the piston to a connecting rod (13) of the internal combustion engine, with an intermediate inner cooling space (15) for cooling oil for cooling the piston formed by the piston upper part (10) and the piston lower part (1), which has at least one transfer bore (17) with an outer cooling space (11) between the upper piston part (10) and a lower piston part (11). 16) is connected, and with one in the piston lower part (11) movably mounted, one-piece slide shoe (19) which is pressed via a spring element (20) against a connecting rod (14) of the connecting rod (13) and the transfer of through a bore ( 18) in the connecting rod (13) guided cooling oil into the inner cooling chamber (15), wherein between the one-piece slide shoe (19) and piston lower part (11) has a guide surface (21) for the formed one-piece slide shoe (19), characterized in that the spring element (20) seen in the axial direction of the piston or sliding shoe extends at least partially parallel to the guide surface (21) for the one-piece slide shoe (19).

2. Piston according to claim 1, characterized in that the guide surface (21) for the one-piece slide shoe (19) surrounds the spring element (20) radially outside at least in sections.

3. Piston according to claim 1 or 2, characterized in that the spring element (20) as seen in the radial direction of the piston or sliding shoe is positioned radially within the guide surface (21) for the one-piece sliding shoe (19). Piston according to one of claims 1 to 3, characterized in that the spring element (20) on the one hand on the one-piece slide shoe (19) and on the other hand on the piston lower part (11) is supported.

Piston according to one of claims 1 to 4, characterized in that the one-piece slide shoe (19) has a neck-like end (23) and a funnel-like end (24), wherein the funnel-like end (24) via the spring element

(20) against the connecting rod (14) of the connecting rod (13) is pressed, and wherein starting from the funnel-like end (24) at least partially radially outwardly around the neck-like end (23) around a projection (25) with a radial distance to the neck-like end (23) extends.

Piston according to claim 5, characterized in that the guide surface

(21) for the sliding shoe (19) between the projection (25) and the piston lower part (11) is formed.

Piston according to Claim 5 or 6, characterized in that the spring element (20) extends into a free space (26) formed between the projection (25) and the neck-like end (23).

Sliding shoe for an oil-cooled piston of an internal combustion engine, which can be pressed via a spring element (20) against a connecting rod head (14) of a connecting rod (13), wherein a guide surface (21) for the one-piece sliding shoe is formed between the integrally designed sliding shoe and the piston lower part, characterized in that viewed in the axial direction of the sliding shoe, the spring element (20) extends at least in sections parallel to the guide surface (21) for the one-piece sliding shoe. Sliding shoe according to claim 8, characterized by features according to claims 2 to 7.