DE1905029C - Pistons for direct injection internal combustion engines - Google Patents

Description

50

The invention relates to a piston for direct injection Internal combustion engines, with an inserted in its base, firmly connected to it, Combustion chamber insert adapted in shape to the respective combustion process, one above the combustion chamber insert Slid-on and tightly welded shell, through which an inner cooling chamber for regulation the temperature of the combustion chamber wall is formed, and external cooling for the piston rings receiving piston skirt as well as for the indirect cooling of the one located in the inner cooling space Coolant with partial and full load operation of the machine.

Such a piston is already made by the Dutch U.S. Patent 133,649 (published January 1969) is known. With him is the inner cold room completely closed and partially with a metallic or non-metallic thermally conductive material from filled with a predetermined melting point. Below this melting point, i.e. H. if the substance is in the rigid state at the bottom of the cold room, it forms only a small heat transfer surface between the combustion chamber wall and the shell, because the rest of the air-filled part of the cooling chamber has an isolating effect. When the combustion chamber wall has reached a predetermined temperature, the metallic or non-metallic substance liquid and fills the piston moving up and down entire cold room, creating a large heat transfer efficiency arises. In this way, the combustion chamber wall is when starting, idling and in the lower partial load range of the engine when it is theirs Has not yet reached the setpoint temperature, is essentially insulated and only after the intensively cooled at a favorable combustion chamber temperature.

The engine lubricating oil is expediently used as the coolant for the external cooling system is subject to a continuous cycle. It has the task of the piston jacket carrying the piston rings at a decidedly lower temperature than should prevail in the combustion chamber wall and also the one on the inside of the refrigerator excess heat given off to the shell to take away from the Kolhtn.

Hrennkraftmaschinen with the two described Effort h / w. such an arrangement of Cooling systems have become particularly popular today usual high-performance motors very well proven. Since the piston itself is executed as a cast or pressed body However, it must be in the upper area, where the heat-resistant steel combustion chamber insert is screwed in and the corresponding cooling spaces are to be provided, designed to be relatively stable which makes it too heavy for the engines specifically designed for it. Further is due to the thick walls of the especially cast light metal piston, which is a good Resulting heat conduction, the piston ring section is still partly heated too much and through Jas large jacket voluirr.n of the piston a part of the heat to be given off by the coolant is stored or handed over to the Zvlinder wall. This heat storage allows for higher thermal Load on the piston easily cracks or other damage, e.g. seizing of the piston rings, appear.

What about the reduction in weight and the transfer of heat from the combustion chamber to the piston ring area or cylinder space is concerned, it is already known, for example from German patent specification 472 633, a piston made of several individual parts, which have thinner walls and cavities can be provided to assemble. The piston according to the patent mentioned consists of one hollow inside, the piston crown, part of the combustion chamber wall and part of the piston ring area forming ring part, which is connected to the piston skirt by screws. The lower Part of the combustion chamber wall is made up of two nested between the jacket and the ring part trapped shell body formed. The design brings a lighter piston, but it does is not suitable for high-performance engines because there is no cooling, only isolation rooms for the Combustion chamber, the piston crown and the ring belt

having. This has the consequence that the heat is all the more intense over the piston body and the piston rings is derived from the cylinder wall. There can be no talk of temperature control.

The object of the present invention is to provide a lightweight piston of the type described in the opening paragraph, i. H. adapted with a & = ^ rapid combustion process To create combustion chamber and two different, independent cooling systems, in which the mentioned disadvantages are avoided, with particular emphasis on a high thermal resistance and good heat dissipation to the cooling device Aie object is achieved in that the combustion chamber insert is known per se Way is firmly connected to the ring carrier by a weld and that the from the combustion chamber insert, the ring carrier and the shell with a piston top part that accommodates the piston pin, rigidly attached sliding shoes bearing piston ao Lower part can be precisely joined together in the axial and radial direction by means of a centering and by means of a Weld is firmly connected.

The centering consists of a provided at the bottom of the combustion chamber insert, in its ₅ * height limited spigot and benunterteil koi arranged on a, fitted in the centering centering hub.
Z

^ine % ^Lag fr, composite Ko 'composed of individual parts κ

constantly with a _betwee n the ring t RAE

^throw . ^ "ijl, _nee o dneten and with these dough and the Scha * ^ ecr ßbegrenzungskör-

len by ^S _f ^c ~ ^en ^ ^r _{to bodies are} formed eniper death. im «eg κ £ * ^ ^

Speaking openings or υ ig Coolant * - and - ^ «^ g« i from the following

Details of the " ¹ ""β β drawings dagenden B ^^^^ SS» provided

Fig. I, ^ F i g. 2 a section through the Ko.ben along u

Line I-I in Fig. 1, whores the top i

F i g. 3 walking around for a _{long time} ;

one of the execution according to. £ _ß

Piston, but with a closed lie.

Cold room. it

In the F.guren s.nC der
the ring bearer with 2, which the
closing bowl with 4, cia.
and the sliding shoes with 6 ^^

As can be seen from Fig. 1 has over au. "umeinsau 1 at its the combustion chamber / aoge a ...

th surface an upper and a mW « »> ^ Uf, with which d, e pushed ^ chale 4 d

is welded. A here in Kolbei ⁿ ™ s ago ^ ... hene weld 10 connects the combustion chamber.

15th

as

gp

in this context the early Sch

French patent 838215 pointed out, after the 30th sentence 1 with the ring carrier * κ _ρί ; _η Η _Ρ τ ,,

an oil-cooled, which at the same time forms the piston crown

the ring carrier by means of screws on a piston ^ l ™haben ^ "

is attached to the lower part to which sliding shoes are also attached. Ring carrier and piston lower part are fixed to one another by a centering acting in the axial and radial directions. Because the Centering already has a relatively large diameter and only outside of it the fastening screws are arranged, is created between the ring carrier and the lower part

large heat transfer surface, whereby the sliding

shoes and the piston pin unnecessarily heated will. Apart from that, the piston is for quick-

running engines completely unsuitable, he has no g.

Combustion chamber and no two cooling systems and he can be set to 45, has two Jr

represents a heavy construction in terms of weight, provided bores 15 for receiving

so that he in no way does justice to the task set here

⁸ In order to achieve the largest possible heat transfer surfaces to the coolant in the present invention

Create and reduce the piston weight as much as possible to reduce it is proposed as a further development, on the outer wall of the combustion chamber insert to the top

ren and lower limit mg of the inner cooling space the sliding shoes 6 on the j ^

to provide a collar in each case, with which the shell _{55 on} the expansion studs 16 centner collar _{18 z} "

is tightly welded. proper definition of the sliding blocks 6 angc

It also adds weight and manufacturing costs. . . ",. «Λ Pi ο 1 an

to save, still proposed, the piston lower part In F ₁ g 3, the piston according to Figl has one

as a U-shaped bracket with holes in its thighs

one measured in height
the one on the piston part 5 v hub 12 is fitted. By centering out. the combustion chamber insert 1, the King ^ "· -> - the shell4 existing Ko.oenoberte ^ both., axially as well as in the radial direction to the door part and fixed by a Sch _;;

firmly connected to this In the rig..1 _;

Bund9 on the outside
provided, but he can
be trained. There, ™
which for example by
gen one originally " ^ache . ⁿ thinks two

piston pin shown. To Jen both you. Long sides of the bores 15 are opposite to one another

overlying the two sliding shoes 6 on the piston

part 5 attached. r.lpitsrhuhe

From Fig. 2 it can be seen that the shoes are fastened to the piston lower part 5 by expansion screws 16 and nuts 17 at the points where the sliding shoes 6 are attached to the piston lower part J

16 Zbd ₁

In F ₁ g. 3, the piston according to Fig

g, closed outer Kuhlrauro, 19 'on the

to accommodate the piston pin provided bracket 60 by a on the inner wall ^ s lüngtrage «2 and to train. Such a bracket can toh au geschwuß ^of-way in a simple on the outside wall of Schale4 <. a flat material, with openings 20 for the Kuhlm.ttele.n-_ and and does not represent an expensive casting. will. This execution is, as suggested

Finally, it should be mentioned that the invention was mainly used for pistons with larger diameters

bl or gedac from highly planted engines! J. who "* e

The heat dissipated by the Spntzol is not sufficient Cooling does more.

Appropriate pistons for particularly heavily loaded engines or for large designs to increase the external cooling

1 sheet of drawings

Claims (4)

Patent claims: 1. Pistons for direct injection internal combustion engines with a piston inserted into its bottom, firmly connected with it, adapted in its shape to the respective combustion process Combustion chamber insert, one pushed onto the combustion chamber insert and welded tightly Shell through which an inner cooling chamber regulates the temperature of the combustion chamber wall is formed and an external cooling for the piston skirt receiving the piston rings as well for the indirect cooling of the coolant located in the inner cooling space with partial and Full load operation of the machine, characterized in that the combustion chamber insert (1) in a known manner by a Welding *. (10) is firmly connected to a ring carrier (2), and that from the combustion chamber insert (1), the ring carrier (2) and the shell (4) Existing piston upper part with a rigidly attached piston pin that receives the piston pin Sliding shoes (6) supporting piston lower part (5) in the axial and radial direction by a centering (Parts 11, 12) can be assembled exactly and firmly connected by a weld seam (13). 2. Piston according to claim 1, characterized in that the axial and radial fixing of the piston upper part to the piston lower part (5) through one at the bottom of the combustion chamber insert (1) provided centering shoulder (11) with a limited height and one on the piston base! (5) arranged, fitted into the centering recess '' H) Centering hub (12) takes place. 3. Piston according to claim I, characterized in that that on the outer wall of the combustion chamber insert? (1) to the upper and lower limit of the inner cooling chamber (4) each have a collar (8, 9). with which the shell (4) is tightly welded. 4. Piston according to claim 1, characterized in that the piston lower part (S) is designed as a U-shaped, in its legs groove bores (15) provided for receiving the piston pin bracket.