RU2767582C2 - Cylinder-piston group - Google Patents

Abstract

FIELD: engine technology.

SUBSTANCE: cylinder-piston group of an internal combustion engine contains a cylinder sleeve (1) with a piston (2) installed in it, equipped with piston rings (3). The cylinder sleeve (1) is equipped with electromechanical vibrators, which are piezoelectric plates (4) equipped with electrical contacts for supplying alternating electric voltage to them. Vibrators in the amount of two pieces are located on the outer surface of the sleeve (1) of the cylinder at a distance from 1/3 to 1/2 of the height of the sleeve (1) of the cylinder from its upper edge. Vibrators are made in the form of two diametrically arranged arc-shaped conical piezoelectric plates (4) rigidly attached to the outer surface of the cylinder sleeve (1) in the plane of the connecting rod swing. The angular length of the arc-shaped piezoelectric plates (4) of vibrators in a plane perpendicular to the axis of the cylinder is from 20 to 30 degrees. The angle of inclination of the cones of the plates (4) of vibrators to the axis of the sleeve (1) of the cylinder is from 30 to 45 degrees to create transverse-longitudinal ultrasonic mechanical vibrations of the working inner surface of the sleeve (1) of the cylinder when starting the engine and in the mode of its post-start heating.

EFFECT: reducing the friction force in the cylinder-piston group and the wear rate of its parts when starting the engine and during its post-start warm-up mode.

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Description

The invention relates to mechanical engineering and can be used in reciprocating machines, mainly in internal combustion engines, as well as in reciprocating machines such as reciprocating compressors, reciprocating external combustion engines. The invention is aimed at improving the durability and efficiency of reciprocating machines by reducing the friction force in the cylinder-piston group and reducing the wear rate of its parts.

The cylinder-piston group consists of a cylinder sleeve and a piston with rings placed on it, reciprocating inside the sleeve. Together, the cylinder liner and piston form a rubbing pair. The presence of friction forces in the cylinder-piston group leads to mechanical energy losses in the engine, which reduces its efficiency. This is especially true for high speed engines. Operational wear of the friction surfaces of the cylinder liner, piston skirt and piston rings determine the durability of the engine. In addition, with an increase in wear, the working process of the engine deteriorates due to the breakthrough of gases from its working chamber and the efficiency of the engine decreases.

To reduce friction forces and wear of parts of the cylinder-piston group, lubrication of parts is used. The main factors that make it difficult to lubricate the cylinder-piston group are as follows:

- the difficulty of delivering a lubricating fluid, which is usually oil, to rubbing surfaces;

- a significant dependence of the lubricity of the lubricant, in particular its viscosity, on the temperature of the rubbing surfaces;

- uneven temperature of the cylinder sleeve along its height;

- a significant dependence of the conditions for ensuring effective lubrication on the engine operating modes, which in the general case of operation vary in a wide range from engine start and its post-start warm-up mode to nominal and maximum allowable power modes;

- since the movement of the piston in the cylinder is reversible, reciprocating, then in the regions of the upper and lower dead points, the speed of the piston is equal to or close to zero, which greatly complicates the formation of a stable lubricating layer between the friction surfaces of the cylinder liner and the piston.

The technical problem is that it is difficult to ensure minimum friction forces and wear of the cylinder-piston group in a wide range of engine operating modes, including its start and post-start warm-up. When starting the engine, the most unfavorable conditions for the lubrication of the cylinder-piston group take place. This is due to the fact that when the engine is started, the temperatures of its parts are low, the viscosity of the lubricating fluid is high, as a result of which there are no conditions for the formation of a stable layer of lubricating fluid between the rubbing surfaces. In addition, at the initial moment of starting the engine, its mechanism, including the piston, is stationary. The lubricating fluid practically does not yet reach the rubbing surfaces. In addition, when starting the engine, there is the largest diametrical clearance between the piston and the cylinder liner, which further complicates the formation of a lubricating layer between the rubbing surfaces. These factors together lead to the fact that when starting the engine, there is dry or semi-fluid friction between the cylinder liner and the piston, in which there is a complete or partial absence of a layer of lubricating fluid between the rubbing surfaces. In this case, metal-to-metal friction occurs, which leads to a high wear rate of parts.

It is known that the total wear of the parts of the cylinder-piston group for a certain period of engine operation is largely determined by the amount of wear that occurs during engine starts and its post-start warm-up modes. To the greatest extent, this is typical for engines, the operation of which involves frequent stops and starts of the engine. Wear of parts of the cylinder-piston group, namely the wear of the inner working surface of the cylinder liner, piston rings and piston skirt, leads to a decrease in engine durability. In addition, with increasing wear, the efficiency of the engine's working process decreases in all modes of its operation due to the breakthrough of gases from its working chamber, the efficiency of operation decreases and the emission of toxic substances with exhaust gases increases.

A device of a cylinder-piston group is known, described in patent RU 2616426 C1 (publ. 14.04.2017). The cylinder-piston group contains a piston with rings placed on it, in contact with the cylinder sleeve, which has a microrelief on the working surface. The microrelief is made in the form of uniformly alternating fragments located along helical lines, each of which consists of a groove conjugated with a flat surface section parallel to the cylinder axis. The microrelief increases the reliability of the lubrication of the cylinder-piston group due to the presence of a certain amount of lubricating fluid in the grooves, which contributes to the formation of a lubricating layer between the rubbing surfaces.

The disadvantage of the device is the low efficiency of its operation when starting the engine and in the post-start warm-up mode. This is due to the fact that in these modes the supply of lubricating fluid to the rubbing surfaces is absent or insufficient. In addition, the relatively low temperature of engine parts and lubricating fluid makes it difficult to form a lubricating layer between the rubbing surfaces. Under such conditions, there is an unfavorable mode of dry or semi-fluid friction in the cylinder-piston group, despite the presence of a microrelief on the cylinder liner.

A device of a cylinder-piston group is known, described in the patent SU 1663220 A1 (publ. 15.07.1991). By the combination of features, this device is the closest analogue of the claimed invention.

This device consists of a cylinder liner with a piston installed in it, equipped with piston rings. Groups of radially directed vibrator belts are installed in the middle part of the cylinder bushing. Moreover, the active surface of these vibrators coincides with the inner surface of the cylinder sleeve, and electromechanical transducers are fixed on the outer surface of the sleeve. The vibrators are metal cylindrical rods glued into radial through holes in the middle part of the cylinder bushing. These rods oscillate in the radial direction with respect to the axis of the cylinder and create a vibration directed perpendicular to the friction surfaces of the cylinder liner and piston.

The device of the closest analogue allows to increase the efficiency and power of the engine by reducing viscous friction in the lubricating layer and the consumption of lubricating fluid for waste. The reduction of the friction force in the cylinder-piston group of the closest analogue is achieved due to the fact that these vibrators, making mechanical vibrations along their longitudinal axis, create pressure fluctuations in the lubricating fluid layer.

The disadvantage of the device of the closest analogue is the low efficiency of its operation when starting the engine and in the post-start warm-up mode. This is due to the fact that, as indicated above, when starting the engine and in the warm-up mode, there is practically no continuous layer of lubricating fluid between the rubbing surfaces in the cylinder-piston group. Therefore, an attempt to excite any vibrational field in the lubricating fluid layer is ineffective due to the absence of this lubricating layer itself.

In addition, the disadvantage of the device of the closest analogue is that it provides for a set of through radial holes in the cylinder sleeve, which reduces the strength of the sleeve itself and creates the prerequisites for a violation of the tightness of the working chamber of the engine cylinder.

In addition, the device of the closest analogue provides for the creation of exclusively transverse vibration, i.e. vibration directed perpendicular to the rubbing surfaces. As a result, the closest analogue has limited efficiency, since it excludes the potentially beneficial effect of longitudinal vibration on the friction process, i.e. vibration directed parallel to the rubbing surfaces.

From the prior art, in addition to the above, it is known that the dry friction force can be significantly reduced by vibrating the friction pair, see [Bykhovskiy I.I. Fundamentals of the theory of vibration technology. - M.: Mashinostroenie, 1968 - p. 308-312], [Vibrations in technology: a Handbook. - Volume 4 - Vibration processes and machines / Ed. E.E. Lavendel. - M.: Mashinostroenie, 1981. - p. 457-458]. If one of the rubbing surfaces performs high-frequency mechanical vibrations, then the effective coefficient of dry friction decreases. In the general case, to create the indicated physical effect, mechanical vibrations must be directed both in the transverse and longitudinal directions with respect to the rubbing surfaces. In addition, as a rule, the most effective for the application of the specified physical effect is the use of high-frequency mechanical vibrations in the ultrasonic frequency range. Due to this, energy losses to overcome frictional forces are reduced, the wear rate of parts is reduced, and the efficiency and durability of the machine operation are increased. A low friction bearing arrangement is known, as described in US Pat. No. 3,239,283 (publ. March 8, 1966). In this device, this physical effect is usefully used to reduce the force of dry sliding friction in friction pairs.

The technical problem to be solved by the invention is to reduce the friction force in the cylinder-piston group and the wear rate of its parts when starting the engine and in the mode of its post-start heating. The problem is solved by the fact that the device contains electromechanical vibrators that create transverse-longitudinal ultrasonic mechanical vibrations of the working inner surface of the cylinder liner when the engine is started and in the mode of its post-start heating, when there is dry or semi-fluid friction between the cylinder liner and the piston.

The device of the cylinder-piston group is shown in Fig. 1, 2, 3. The cylinder-piston group of the internal combustion engine consists of a cylinder liner 1 with a piston 2 installed in it, equipped with piston rings 3. Two electromechanical vibrators are installed on the outer cylindrical surface of the cylinder liner, which are arcuate conical piezoelectric plates 4 with electrical contacts, rigidly attached to the outer surface of the cylinder sleeve 1. The principle of operation of electromechanical vibrators is based on the physical piezoelectric effect. On the inner and outer conical surfaces of the plates 4, made of piezoelectric material, electrical contacts are applied, to which electrical conductors are connected for supplying alternating electrical voltage.

The conical piezoelectric plates 4 are rigidly attached to the outer surface of the cylinder sleeve 1 by means of intermediate cone plates 5, which are made of electrically insulating material and are fixedly connected to the outer surface of the cylinder sleeve 1 and to the inner surface of the cone plates 4 by means of adhesive joints. In this case, in working condition, the rigidity of the intermediate cone plates 5 and the above adhesive joints must be high enough to effectively transfer mechanical vibration from the plates 4 of the vibrators to the inner surface of the cylinder sleeve 1.

These vibrators 4 in the amount of two pieces are located on the outer surface of the cylinder sleeve 1 at a distance of 1/3 to 1/2 of the height of the cylinder sleeve from its upper edge.

At the same time, these vibrators are made in the form of two diametrically located arcuate conical piezoelectric plates 4, rigidly attached to the outer surface of the cylinder sleeve 1 in the swing plane of the connecting rod. Moreover, the angular length of the arcuate plates 4 of the vibrators in a plane perpendicular to the axis of the cylinder is from 20 to 30 degrees.

The angle of inclination α of the cones of the plates 4 of the vibrators to the axis of the sleeve of the cylinder 1 is from 30 to 45 degrees.

The essence of the invention lies in the fact that, unlike the closest analogue, the cylinder-piston group contains vibrators that create transverse-longitudinal ultrasonic mechanical vibrations of the working inner surface of the cylinder liner. In addition, the invention, unlike the closest analogue, does not violate the integrity of the wall of the cylinder liner, which contributes to maintaining its strength, as well as maintaining the tightness of the working chamber of the internal combustion engine.

In FIG. 1 shows a cylinder-piston group.

In FIG. 2 shows the section A-A of the cylinder-piston group.

In FIG. 3 shows the device of the vibrator of the cylinder-piston group.

In FIG. 1, 2, 3 are marked: 1 - cylinder sleeve; 2 - piston; 3 - piston rings; 4 - piezoelectric vibrator plate; 5 - intermediate conical plate for fastening the vibrator. The arrows show the direction of the mechanical vibration generated by the vibrators.

Cylinder-piston group works as follows. The piston reciprocates inside the cylinder liner. Friction forces arise between the cylinder liner and the piston, which lead to energy losses and wear of parts. As a result of applying an alternating electrical voltage to the contacts of the cone plates 4, which are located on their inner and outer surfaces, these piezoelectric plates 4 experience variable compression-tension strains, i.e. excite high-frequency mechanical vibration of the ultrasonic range. In this case, the frequency of the excited mechanical vibrations is equal to the frequency of the alternating electrical voltage applied to the contacts of the plates 4. This vibration is transmitted to the cylindrical wall of the sleeve of the cylinder 1 through the intermediate conical plates 5 of the vibrators.

As a result of this, as well as the fact that the plates 4 of the vibrators have a conical shape, the working inner surface of the sleeve of the cylinder 1 performs mechanical vibrations both in the transverse and longitudinal directions with respect to the axis of the cylinder, i.e. in relation to the rubbing surfaces of the cylinder-piston group.

The specified vibration of the working inner surface of the cylinder liner 1 helps to reduce the effective coefficient of friction, as well as mechanical energy losses in the cylinder-piston group, during such important operating modes as engine start and post-start warm-up, when there is dry or semi-fluid friction between the cylinder liner and piston. In addition, this vibration helps to reduce the rate of operational wear of parts of the cylinder-piston group, namely the friction surfaces of the cylinder liner, piston skirt and piston rings.

Thus, in the inventive cylinder-piston group, in contrast to similar devices, a reduction in the friction force and the wear rate of parts during engine start-up and in the mode of its post-start heating is ensured, which increases the durability and efficiency of piston machines.

The claimed device is industrially applicable, since for its implementation it is sufficient to use well-known methods for the manufacture and installation of parts from standard structural materials.

Claims (1)

Cylinder-piston group of an internal combustion engine, containing a cylinder liner with a piston installed in it, equipped with piston rings, while the cylinder liner is equipped with electromechanical vibrators, which are piezoelectric plates equipped with electrical contacts for supplying alternating electrical voltage to them, characterized in that vibrators in the amount of two pieces are located on the outer surface of the cylinder sleeve at a distance of 1/3 to 1/2 of the height of the cylinder sleeve from its upper edge, while the vibrators are made in the form of two diametrically located arcuate conical piezoelectric plates rigidly attached to the outer surface of the cylinder sleeve in the swing plane of the connecting rod, wherein the angular length of the arcuate piezoelectric vibrator plates in the plane perpendicular to the axis of the cylinder is from 20 to 30 degrees, while the angle of inclination of the cones of the vibrator plates to the axis of the cylinder sleeve is from 30 to 45 degrees c to create transverse-longitudinal ultrasonic mechanical vibrations of the working inner surface of the cylinder liner when starting the engine and in the mode of its post-start heating.

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