RU2750829C1 - Piston of internal combustion engine - Google Patents

Abstract

FIELD: internal combustion engines.

SUBSTANCE: piston of the internal combustion engine has a tool that ensures low vibration and low noise of the piston and the engine as a whole. The tool is made in the form of a solid U-shaped insert in the inner cavity of the piston with the upper round part and the side parts. The side parts are made in the form of quad springs (5) with curvature. The fixed part of springs (5) is insert base (4), and the free parts are bosses (6) of the piston pin with conical support surfaces. Springs (5) with bosses (6) are isolated from piston skirt (2). Insert base (4) is fixed by the outer transverse plane to inner plane (14) of the piston bottom. The cylindrical plane of the insert rests on upper – heat belt (1) on the inner side.

EFFECT: technical result is reducing not only the noise of mechanical origin from impacts in the rod-crank mechanism, but also the noise of gas-dynamic origin from the combustion process, caused, due to a sharp change in pressure, by impacts in the joints of the rod-crank mechanism.

1 cl, 5 dwg

Description

The invention relates to the field of mechanical engineering, in particular, engine building, and more specifically to improving the design of the piston of internal combustion engines (ICE) and other piston machines (compressors, pumps, machine tools, etc.).

The general noise and vibration levels of the internal combustion engine are determined by the noise and vibration levels of various radiation sources. The main sources of airborne noise are turbochargers, body parts, fuel pumps, gearboxes, gas distribution mechanisms, intake and exhaust manifolds, and exhaust systems. The main causes of vibration include unbalanced forces and moments, overturning moment, workflow, shifting processes within gaps in movable joints and associated (torsion-flexural-axial) vibrations.

The most intense source of vibration and, as a consequence, noise of an internal combustion engine of mechanical origin, are vibrations of cylinder bushings and internal combustion engine blocks, resulting from shifting ("sloughing") and tilting of the pistons within the thermal gap.

The main source of ICE noise is mechanical shocks in the connecting rod-crank mechanism ("piston - finger, piston - connecting rod head bearing - connecting rod crank bearing - crankshaft - crankshaft main bearing"), the noise level of which is 3-9 dB higher than the levels of others sources of noise of mechanical origin. The increase in engine noise due to the combustion process (by 2-3 dB) is caused to a greater extent by the intensification of these shocks than due to the gas-dynamic phenomena of the combustion process.Piston designs aimed at ensuring low vibration and low noise of the internal combustion engine are known:

- RF patent No. 2182242: the piston is made with a special insert in the inner cavity of the piston from a vibration-damping composite material in the form of an integral or prefabricated cylindrical body. The upper connecting rod head and the piston pin are attached to the piston through an insert that serves as an acoustic barrier between the parts piston - connecting rod - piston pin;

- RF patent No. 2182243: the piston is equipped with a special non-metallic or polymeric composite multifunctional insert made in the form of a cylinder with an eccentric hole for the piston pin and installed in the pre-enlarged holes of the piston bosses. The multifunctional insert provides not only decontamination of the piston pin, but also the displacement of the center of mass of the piston and vibration damping.

The disadvantages of pistons are the high cost of manufacturing inserts from composite materials and the difficulty of solving the problem associated with low thermal conductivity.

Known RF patent No. 2182244: the piston in the pre-enlarged holes of the bosses contains a means that reduces its vibration activity. The tool is made in the form of a steel cable sleeve with fasteners or a package of steel cylindrical plates or an elastic damping mesh element obtained by cold pressing from a braided steel wire. However, these tools have a complex design and are not reliable enough.

RF patent No. 2263804: the piston is made with a means of reducing the vibration of the engine in the form of packs of cylindrical spring plates installed in the piston head hole of the connecting rod, or simultaneously in the piston bore and in the piston head hole of the connecting rod. The disadvantage of the piston is its limited service life.

Analysis of these designs shows the urgency of the problem of creating low-vibration and low-noise internal combustion engines.

The technical result of the proposed solution is to achieve low vibration and low noise of the internal combustion engine by reducing the noise of mechanical origin, not only noise from impacts in the connecting rod-crank mechanism, but also the noise of gas-dynamic origin from the combustion process caused, due to a sharp change in pressure, by impacts in the joints of the connecting rod-crank mechanism.

The technical result is achieved by the fact that the piston is made with a special insert in the inner cavity in the form of an integral U-shaped body, the upper round part of which is the base of the insert, and the side parts are made in the form of a quadruple (half-elliptical or cantilever) with a spring curvature, the fixed part of which serves as the base of the insert, and the piston pin bosses serve as the free parts of the spring. In this case, the springs with bosses are isolated from the piston skirt. The base of the insert with an outer transverse plane is attached to the inner plane of the piston crown, and with a cylindrical plane rests on the upper - the heat zone from the inner side.

The bosses are made with grooves for the piston pin circlips.

All mating points - fillets of the insert are made with the calculated radius of curvature, and the sharp corners are rounded. The indicated places can be either rolled with shaped rollers or blasted with shot.

The upper part of the insert is made with holes for attaching the insert to the piston crown from its inner part and with a central hole for effective oil cooling of the piston crown.

The springs provide an elastic connection of the piston bosses with its head and assembly by means of the piston pin with the upper connecting rod head, are isolated with design clearances from the inner cavity of the piston in the area of the piston support belt-skirt. This elastic connection and insulation allows the curved springs to bend without plastic deformation in both the vertical and horizontal directions.

Vertical deformation of the springs occurs from the forces of gas pressure and the forces of inertia of translationally moving masses (LDM). Deformations from gas pressure forces are associated with periods of ignition, initial and main combustion, determined by the nature of the initial stage of self-ignition and combustion (uncontrolled combustion period) with intense shock waves and the rate of pressure rise in the cylinder, the sharpness of separation of the combustion line from the compression line.

The horizontal deformation of the springs occurs from the normal - lateral force during the shift (change of signs) of the piston due to the presence of gaps between the piston and the bushing. At the same time, there is a significant softening of these shocks transmitted by the piston in its lateral movement, especially near the top dead center (TDC), and smoothing of the sharp separation of the combustion line from the compression line.

The invention is illustrated by drawings, where Fig. 1 shows a general view of a piston with a means of fastening an insert of screws.

FIG. 2 shows a general view of the piston insert.

FIG. 3 is a view of the piston insert from the end.

FIG. 4 is a side view of the piston insert.

FIG. 5 shows a general view of a piston with a means for attaching the insert by means of a threaded connection of the insert base collar with the inner collar of the upper - head land.

FIG. 1-5 are indicated:

1 - top - top zone corresponding to the piston head; 2 - skirt-supporting belt of the piston; 3 - sealing belt - the location of the piston rings; 4 - base of the piston insert; 5 - springs with curvature; 6 - bosses (supports) of the piston pin; 7 - piston pin bearings; 8 - grooves for piston pin retaining rings; 9 - cavities between the springs; 10 - fillets; 11, 12 - grooves for piston rings; 13 - the bottom of the piston; 14 - inner side of the piston head; 15, 16 - holes; 17 - fastening means; 18 - enlarged conical bearing surface of the bosses; 19 - rounding, 20 - threaded hole in the area of the upper - the top zone.

The main element that ensures the achievement of the technical result is a special one-piece insert in the inner cavity of the piston in the form of a U-shaped one-piece element with an upper round part 4 and side parts made in the form of quadruple (half-semi-elliptical or cantilever) springs 5 with curvature, fixed part which serves as the base 4 of the insert, and the bosses 6 of the piston pin serve as free parts of the springs. The base of the insert 4 with an outer transverse plane is attached to the inner plane 14 of the bottom of the piston 13, and with a cylindrical plane rests on the upper (heat) band 1 from the inner side.

The bosses 6 are made with grooves 8 for the piston pin retaining rings.

All mating points - fillets 10 of the insert are made with the calculated radius of curvature, and the sharp corners 19 are rounded. The indicated places can be either rolled with shaped rollers or blasted with shot.

The upper part 4 of the insert is made with holes 15 for attaching the insert to the piston crown 14 from its inner part and with a central hole 16 for efficient oil cooling of the piston crown.

Springs 5 provide an elastic connection of the piston bosses 6 with its head 1, and assembled, by means of the piston pin, with the upper head of the connecting rod are isolated with design clearances from the inner cavity of the piston in the region of the support belt-skirt 2 of the piston. Such an elastic connection and insulation provides the possibility of deflection of the springs 5 with curvature without plastic deformation in both the vertical and horizontal directions.

Vertical deformation of the springs 5 occurs from the forces of gas pressure and the forces of inertia of translationally moving masses (LDM). Deformations from gas pressure forces are associated with periods of ignition, initial and main combustion, determined by the nature of the initial stage of self-ignition and combustion (uncontrolled combustion period) with intense shock waves and the rate of pressure rise in the cylinder, the sharpness of the separation of the combustion line from the compression line ("Impact research piston in trunk diesel "V. I. Zinchenko, TSNIMF, 1971, issue 146, p. 95)

The horizontal deformation of the springs 5 occurs from the normal - lateral force during the shift (change of signs) of the piston due to the presence of gaps between the piston and the bushing. At the same time, there is a significant softening of these shocks transmitted by the piston in its lateral movement, especially near the top dead center (TDC) and smoothing of the sharp separation of the combustion line from the compression line.

When the engine is running, the springs 5 of the piston insert, perceiving the force of gas pressure from ignition, initial and main combustion and the inertial force of the LDM, bend by a calculated value. In this case, the volume of the combustion chamber increases by a calculated value, due to which the maximum combustion pressure in the engine cylinder decreases, and the impacts in the bearings of the KShM are softened. All this helps to reduce vibration and dynamic loads. In the process of reciprocating movement of the piston, the connecting rod of the engine makes a rocking motion, in which the axis of the piston head of the connecting rod is deflected by a certain angle to one side or the other, depending on the magnitude and direction of action of the normal force causing the piston to shift. In this case, the springs, deforming, soften the impact. The shifting and tilting of pistons within the thermal gap is the most intense source of vibration and, as a result, noise of diesel engines of mechanical origin.

Thus, due to the elastic calculated vertical (axial) and horizontal (lateral) deformations of the springs 5 of the insert, the improved design of the piston, from the blows of the connecting rod-crank mechanism and the combustion process, the achievement of low vibration activity and low noise of the internal combustion engine is ensured.

The presented piston design can be used, among other things, in other piston machines and mechanisms, for example, in compressors, pumps, etc.

As part of practical implementation, at the first stage, it is planned to manufacture a prototype of the presented piston design for a four-stroke engine with a dimension of H 8.5 / 11 in the laboratory of the Department of Marine Internal Combustion Engines and Diesel Plants within the framework of training bachelors, masters or graduate students.

Claims (1)

The piston of an internal combustion engine, characterized by the presence of a means that ensures low vibration and low noise of the piston and the engine as a whole, made in the form of a one-piece U-shaped insert in the inner cavity of the piston with an upper circular part and side parts made in the form of quadruple springs with curvature, the fixed part of which serves as the base of the insert, and the piston pin bosses with conical bearing surfaces serve as free parts, while the springs with the bosses are isolated from the piston skirt, the base of the insert is fixed on the inner plane of the piston bottom by the outer transverse plane, and the cylindrical plane rests on the top - the top plate from the inner side ...

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