SU964211A1 - Piston - Google Patents

Description

(5+) PISTON

one

The invention relates to mechanical engineering, in particular to engine-building, with reference to pistons with heat-protective coatings.

A light alloy piston is known for an internal combustion engine, comprising a housing and a combustion chamber in its bottom with a heat insulating insert disposed therein, the surfaces of which are made Q with protrusions 1.

A disadvantage of the known piston is the low reliability of the piston due to overheating of the insert, its high temperature and uneven removal of heat from the insert, as well as different values of the linear expansion coefficients of the insert and piston materials; limited possibility of the engine forcing limit caused by 20 increase in the thermal resistance of the piston with increasing heat load, which causes an increase in the temperature of the insert surface; low surface temperature of the insert at partial loads, which reduces the efficiency of the engine.

The purpose of the invention - improving the reliability of the piston.

This goal is achieved by the fact that the insert is made multi-layered with the main and outer layers and connected to the piston body with an elastic element, and the dimensions of the insert layer are made in accordance with the ratio L- (0.1-0.5) a ciO, 01 b d 0.05 b.) Sf "0.5 a where a is the thickness of the base layer;

B is the thickness of the outer layer; , c - height of protrusions from the side

combustion chambers; d - the height of the projections from

Claims (1)

piston housing; f is the thickness of the elastic element. FIG. 1 shows a piston with an insert and an elastic element; in fig. 2 - piston bottom with an insert with two outer layers with a thickness of the elastic element equal to the sum of the heights of the projections on the surfaces of the outer layer of the insert and the body of the piston bottom; in fig. 3 - the same, with one outer layer with the thickness of the elastic element greater than the sum of the heights of the protrusions on the surfaces of the insert and the body of the piston bottom. The piston (Fig. 17) consists of a body 1 made of a light alloy (for example, silumin), a bottom 2, consisting of a body of piston 1 and an insert 3 connected to the body of piston I by an elastic element k. installed in the cavity 6 of the body of the piston 1. The insert 3 is multilayered (Fig. 2) consists of the main 7 and outer 8 layers and one outer 8 layer (Fig. 3). and from the side of the body 1, the bottom of the piston are projections 10. Between the protrusion 10 on the outer layer 8 and the projections 11 on the surface the body of the bottom of the piston is an elastic element k with a thickness equal to the sum of the heights of the projections 10 and 11 (Fig. 2) and larger than the sum of the heights of the projections 10 and 11 (Fig. 3). from heat-transparent flame material), on the surfaces of which protrusions 9 and 10 are made. Hopius Hb operates as follows. The heat flux absorbed by the outer surface 8 of the insert 3 is supplied to the base layer 7 of the insert without change, since the outer layer 8 of the insert 3 has a high thermal conductivity. At the same time, due to thermal conductivity, the heat flux is redistributed along the surface of the insert, which flattens its temperature by reducing the temperature at the hottest places of the insert. The main layer 7 of the insert 3 is exposed to the already aligned stationary thermal current 114, which is reduced due to the low thermal conductivity of the main layer 7 of the insert 3. The redistribution of heat along the insert 3 by the main layer 7 is not carried out. The main layer 7 of the insert 3 completely quenches the temperature fluctuations caused by the cyclic effect of the applied heat flux and under transient loading conditions. The second outer layer 8 levels the heat flux similarly to the first layer supplied to the elastic element it, which protects it from local overheating. The elastic element reduces the body temperature of the bottom of the piston 1 and compensates for the difference in the relative displacements of the body of the piston 1 and insert 3, caused by their unequal heating and the difference in the coefficients of linear expansions of materials. In this case, the elastic element i provides, regardless of the temperature state of the piston 1 and the insert 3, the value of thermal resistance. The height of the protrusions 10 on the surface of the outer layer 8 and 11, as well as on the surface of the body of the bottom 2, provides a predetermined thickness of the elastic layer; 4, i.e. its thermal resistance. The body of the bottom 2 piston additionally reduces waste. Thus, the proposed piston device increases the decrease in heat loss with increasing heat load. As shown by an experiment conducted with the proposed piston, the transition of the engine from idle mode to full load changes the body temperature of the piston by 10 ° C and 50U of the standard piston 70 C. The same increases the reliability of the piston. Claim light alloy piston for internal combustion engine containing body and a combustion chamber in its shape with a heat insulating insert whose surfaces are made with leaks, characterized in that, in order to increase reliability, the insert is multi-layered with the main and outer layers l is connected to the piston body at the aid of an elastic element, the dimensions of the insert are made according to the ratio B (0.1-0.5) a CfO, Q b drf 0,5 b (from "-d), 5a where a is the thickness of the primary L is the thickness of the outer с - height of protrusions from the side combustion chambers; d - the height of the projections from body: piston; f is the thickness of the elastic element. Sources of information taken into account in the examination 1, Patent of Great Britain No. 15196 7, cl. F / B, pub. 1978 J s f1 / g. /