RU2182242C2 - Piston of internal combustion engine - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: proposed piston is made with special insert of vibration damping composite material in form of solid or sectional cylindrical body. Insert is arranged in inner space of piston. Connecting rod small end and piston pin are connected to piston through insert. Insert serves as acoustic barrier between piston, connecting rod and piston pin. Vibration and noise in internal combustion engine are reduced owing to use of insert made of vibration damping composite material and to reduction of piston mass as a whole and, consequently of inertia forces of translationally moving masses which cause noisy operation and vibrations in engine. EFFECT: improved vibroacoustic characteristics of internal combustion engines and other piston machines. 4 dwg

Description

 The invention relates to the field of mechanical engineering, in particular engine manufacturing, and more specifically to improving the design of the piston, and is aimed at improving the vibro-acoustic characteristics of an internal combustion engine (ICE) and other piston machines (compressors, pumps, etc.).

 Piston designs aimed at improving the vibro-acoustic characteristics of the internal combustion engine are known.

 Known, for example, the piston described in the book: Skuridin A.A. Mikheev E.M. Fighting noise and vibration of marine ICEs. Shipbuilding, L., 1970, 224 p. (p. 141, fig. 74 and 75) (1).

 The specified piston consists of a head, skirt, finger and piston rings.

 The bottom of the piston head is made with a semi-separated chamber in the form of a sphere, an ellipsoid of revolution, for example, a chamber of the TNIDI design (1 p. 141, Fig. 74) and MAN (1 p. 141, Fig. 75).

 However, the indicated design changes of the pistons using semi-divided chambers in the bottom of the head allow one to reduce noise and vibration only of gas-dynamic origin, and therefore, mainly in the high-frequency region.

 The ICE piston is also known, described in the same book (1) p. 97, fig. 48.

 The specified piston of the internal combustion engine contains a cylindrical surface that is conventionally divided into a head, a skirt and a middle part, an internal piston cavity, a piston head bottom, bosses, a piston pin, means limiting the axial movement of the piston pin, piston rings, an insert, and an insert fixing means. The piston insert is made in the form of a cylinder with an eccentric hole and is installed in the holes of the piston bosses instead of the piston pin. The diameter of the boss holes is previously increased to a value sufficient to install the insert.

 The insert is installed in the corresponding hole of the bosses so that the eccentricity of the hole relative to the longitudinal axis of the piston is maximum, i.e. to maximize hole disassembly.

 The piston pin is installed in the eccentric bore of the insert and thereby ensures the piston pin is decontaminated, which helps to reduce the shock impulse and torque of the overturning piston within the thermal gap between the piston and the cylinder bushing.

Significant disadvantages of this piston are the following:
- an insert with an eccentric hole, firstly, significantly increases the mass of the piston and, secondly, shifts the center of mass of the piston both along and across the axis of the piston, and the lateral displacement is opposite to the axis of the finger (displacement);
- piston pin de-massage, firstly, limits the possibility of placement and installation of the connecting rod upper head from the side of the disassembly, since the distance from the axis of the finger to the inner piston wall decreases, and, secondly, it prevents the connecting rod from swinging, i.e. the angle of deviation of the connecting rod from the side of the unloading is limited.

The present invention is aimed at improving the pistons of the internal combustion engine. This is achieved due to the fact that:
- cylindrical - the middle part of the piston is made without holes for the piston pin;
- the internal piston cavity is made in the form of a smooth cylinder, which forms the shape of a glass with the internal surface of the piston bottom;
- the insert is placed in the inner cylindrical cavity of the piston and is made of a vibration-damping composite material reinforced with a fibrous filler, for example aluminum, with continuous fibers or with a high-strength steel wire based on carbon fiber, corundum or carborundum, which has good vibration-damping properties, and has the form of a solid or prefabricated cylindrical bodies with a rectangular symmetrical cavity located along its longitudinal axis under the upper connecting rod head and with two axisymmetric holes located perpendicular to the plane of the connecting rod, under the piston pin;
- the means limiting the axial movement of the piston pin is the wall of the inner cylindrical cavity of the piston, the contact between them i.e. the wall and end part (of the finger) can be either direct or through a plug made also of composite material and serving as an acoustic barrier, or without contact when installing snap rings at the ends of the fingers in the ring grooves provided in the holes for the finger;
- the insert is attached to the piston by fasteners (studs, bolts, circlip, etc.).

 In FIG. 1 shows a General view of the piston in section with all the elements (parts).

 Figure 2,3,4 presents the insert in the form of a solid (figure 3,4) or prefabricated (figure 2) cylindrical body.

 The proposed piston contains a cylindrical surface 1, which conditionally consists of 3 parts: head A, skirt B, middle part C, inner cavity D, piston head E bottom, piston pin 2, means 3 restricting the axial movement of the piston pin 2 of the piston ring 4, inserts 5 and means 6 for fixing inserts 5.

 Positions 7 and 8 indicate the upper head of the connecting rod and its bearing.

 The insert 5 is made of a vibration-damping composite material in the form of a solid (Fig. 3,4) or prefabricated (Fig. 2) body with a rectangular symmetrical cavity F (Figs. 2,3,4) located along its longitudinal axis under the upper connecting rod head and with two axisymmetric holes I, H located perpendicular to the plane of movement of the connecting rod, under the piston pin 2 (figure 1).

 The width G (figure 2, 3, 4) of the cavity F is selected not less than the width of the connecting rod bearing 8 (figure 1) of the upper head 7 from a condition sufficient for the free swinging movement of the connecting rod.

 The connecting rod with the piston is connected by first placing the connecting rod head 7 in the rectangular cavity F of insert 5 with the hole I, H of insert 5 under the piston pin 2, and then installing the piston pin 2 into the hole H, I of the insert and bearing 8 of the upper piston rod of the connecting rod 7.

 The means limiting the axial movement of the piston pin 2 is the wall C of the inner cylindrical cavity of the piston 1, and the contact between them, i.e. the wall and the end part can be either direct or through the plug 9 made of composite material and serving as an acoustic barrier (Fig. 1) or without contact - when installing the snap rings on the ends of the fingers in special ring grooves provided in finger holes (not shown in FIG. 1).

 The plugs 9 may also be provided, for example, additional plugs made of aluminum or steel, are installed in the gap between the wall C of the piston 1 and the plug 9 to prevent possible wear of the plug 9 (a metal plug is not shown in FIG. 1).

 The fastening of the vibration damping insert 5 made of composite material during the operation of the internal combustion engine helps to reduce noise and vibration due to the creation of a full (spatial) acoustic barrier between the upper-piston head of the connecting rod 7, the piston pin 2 and the piston 1 itself.

 The specified acoustic barrier in the form of an insert 5 of a cylindrical body, made of composite material, with complex piston movement and impacts on the cylinder walls, damping, drown out (isolate, reduce) the vibrations and emitting noises transmitted through the walls of the cylinder bushing to the ICE supports and the surrounding Wednesday

 In addition, due to the low weight of the composite material (30-50% lighter than steel), the mass of the piston with an insert made of composite material is less than the mass of the known piston, and therefore, the inertia forces of the translationally moving masses are reduced, which also helps to reduce the noise and vibration of the engine.

Claims (1)

 An internal combustion engine piston comprising a cylindrical surface conventionally divided into a head, a skirt and a middle part, an internal piston cavity, a piston head bottom, a piston pin, means limiting axial movement of the piston pin, an insert and an insert fixing means, characterized in that the cylindrical the middle part of the piston is made without holes for the piston pin, and the internal cavity is made in the form of a smooth cylinder, which forms the shape of a cup with the internal surface of the piston bottom The ka is placed in the inner cylindrical cavity of the piston and is made of a vibration-damping composite material in the form of a solid or prefabricated cylindrical body with a rectangular symmetrical cavity located along its longitudinal axis under the upper head of the connecting rod, and two axisymmetric holes located perpendicular to the plane of movement of the connecting rod, under the piston pin, and the means limiting the axial movement of the piston pin is the wall of the inner cylindrical cavity of the piston, and the contact between them, t i.e. the wall and the end part (of the finger), can be either direct or through a plug made of composite material and serving as an acoustic barrier, go without contact when installing the snap rings on the ends of the fingers in the annular grooves provided in the openings under finger.

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