SU1373846A1 - Piston for internal combustion engine - Google Patents

Abstract

The invention reduces mechanical friction losses. The skirt 2 is made in cross section oval and has a barrel-shaped profile 4, which is made in the form of a set of 4 A5 ff I upper and lower parabolas 5 and 6. The last conjugation point is the top 7 of profile 4. The top 10 of the parabola 5 is located on the end 8 , and the top 11 of the parabola 6 is at the end 9. The top 11 forms an oval 6 of the plane of the end 9. The distance from the top of the skirt profile to the horizontal plane passing through the axis of the holes for the piston pin changes the depth of the profile along the arcs of the cross section of parabolas 5 and 6 in arcs across cross section skirt defined in accordance with certain ratios. The implementation of profile 4 in the form of two parabolas provides the conditions for an effective hydrodynamic lubrication regime with axial movement of the piston in both directions. The position of the tip 7, depending on the position of the center of the piston mass 15 according to the established ratio, ensures uniform lateral movement of the piston. 3 3. P . f-ly, 2 ill. (L oo oo oo. O5 Vut 1

Description

The invention relates to engine building, namely to the design of pistons of internal combustion engines having a barrel-oval shape of a side surface.

The aim of the invention is to reduce mechanical friction losses.

Figure 1 shows a piston with a barrel-oval shape of the lateral pos. BepxHOCTHj in Figure 2 - section A-A in FIG. one.

The piston comprises a head 1 and a skirt 2 which is provided with holes 3 for the piston pin. Skirt 2 is oval in cross section and has a barrel-shaped profile A, which is made as a combination of the top 5 and bottom 6 parabolas. The branch point of the parabolic branches 5 and 6 is the top 7 of profile 4. The piston skirt 2 is bounded by the upper 8 and lower 9 ends. The top JO of the upper parabola 5 is located on the upper end 8, and the top 11 of the lower parabola 6 - on the lower end 9.

The locus of the vertices 7 of the profile 4 located in the horizontal plane is the curve of the oval 12 of the piston. The locus of the vertices 0 of the upper parabolas in the plane of the upper end 8 of the skirt 2 is the curve of the oval 13 of the piston. Similarly, the vertices 11 of the lower parabolas also form an oval in the plane of the end 9.

The distance m from the top 7 of profile 4 to the horizontal plane BB, passing through the axis 14 of the holes 3 for the piston pin, is proportional to the distance 1 from this plane to the center 15 of the piston mass and is determined from the ratio m (0, 9, ... 1.8) 1. The length L of the skirt 2 is the sum of the lengths L p, and L of the sections formed respectively by the upper 5 and lower 6 parabolas.

The depths Kp and K of profile 4 at the locations of the peaks 10 and 11 of parabolas 5 and 6 are variable along the arcs of the cross section of the skirt 2. The depths of profile 4 are maximum in the diametral plane C – C, perpendicular 2 is determined from the following equation:

KB (0.12 ... .0.24) - 0.03oi

K, (0.05, ... 0.10) - 0, OY,

de Cz - depth profile 4 in place

the location of the top 10 of the parabola 5, measured along the Y axis in the plane of the end 8 of the skirt 2:

K - depth profile 4 in place

the location of the top 11 of the parabola 6, measured along the Y axis in the plane of the end 9 of the skirt 2;

the angular coordinate along the arc of the cross section of the piston with the origin from the diametral plane C – C varies within

OS O

 .--

Since the piston has two vertical planes of symmetry, the change in the values of Kg and K „is considered only in one quarter, i.e. when changing the angle ei. from O to “/ 2. In the remaining quarters, K and K are changed in a similar manner.

The exponents Pr and P of the parabolas 5 and 6 are variable along the arcs of the cross section of the skirt 2 and their maximums are in the diametral plane С-С, perpendicular axis 14 of the holes 3 for the piston pin, and minimal in the diametral plane coinciding with the axis 14. The change of the exponents Pv and Pn in the arc of the cross section of the skirt 2 determine Pi3 of the following equations:

Pv (1.83.5) - 0.20

Mon (2.5, ... 3.5) - 0,

where Pd and P c are the exponents of the upper 5 and lower 6 parabolas, respectively. The starting points for building the curved side surface of the piston skirt are the coordinates of the piston 12 oval curve, the length of the skirt and the position of the center of mass 15 of the piston relative to the horizontal plane passing through the axis 14 of the piston holes

the cool axis of the 14 holes 3 for the piston is 55 ° of the finger.

On the basis of these data, the rally plane coincides with the position of the top 7 of profile 4 and axis 14. The change in the depths Kg and Kc depending on the angle θ is the magnitude of Kg, profile 4 along the arc of the cross section , Rg and PM. Then, the current

ordinates top Y | and the bottom U „parabol profile skirt 2 according to the formulas

    R

YH CL - (L1) Pry, L J-JH J

During engine operation, the piston performs a reciprocating axial movement and lateral movement within the cylinder gap. At the same time, by performing the profile 4 of the proposed piston in the form of a combination of two parabolas 5 and 6, the conditions for an effective hydrodynamic lubrication regime are provided with axial movement of the piston in both directions.

Claims (3)

1. A piston for an internal combustion engine, comprising a head and a skirt, provided with openings for a piston pin, made oval in cross-section and having a barrel-shaped profile, is aptly shaped so that, in order to reduce mechanical losses, friction, barrel-shaped The npoijatrib of the skirt is formed by a combination of two parabolas, upper and lower, and its top is located at the intersection point of the latter and is located down from the horizontal plane passing through the axis of the holes under the piston pin, at a distance proportional to the distance from the same plane of the center of mass of the piston, and the profile depths at the locations of the vertices of the upper and lower parabolas and the exponents of these parabolas are variable along the arcs of the cross section of the skirt and their values are maximum in the diametral plane perpendicular to the axis of the holes under piston pin, and minimal in the diametral plane coinciding with this axis, 2. Piston POP.1, characterized in that the distance from the top of the skirt profile to the horizontal plane passing through the axis of the holes under the piston pin is made according to m  (Oh, 9, .., 1.8) 1, 50 five Q 0 five where m is the distance from the top of the profile along a horizontal plane passing through the axis of the holes under the piston pin; 1 - distance from the center of mass of the piston to the same plane, 3. The piston according to claim 1, characterized in that the change in the depth of the profile along the arcs of the cross section of the skirt is determined in accordance with the equations Kg (0,120,24) - 0 ,, Cc - (0.05, ..., 0.10) - 0.01ei, where Kg and Kj are the profile depths at the locations of the vertices of the upper and lower parabolas, respectively; ei is the angular coordinate along the arc of the cross section of the piston with the reference point from the diametrical plane, perpendicular to the axis of the holes under the piston pin, varies within Oi OS 7/2. 4, The piston of claim.), Characterized in that. the variation of the exponents of the upper and lower parabolas along the arcs of the cross-section of the skirt are determined in accordance with the equations П, (1,8, ..., 3,5) - 0,20 «i; P,  (2.5, ..., 3.5) - 0.05ei, where 1 g and Пц are the exponents of the upper and lower parabolas, respectively. / J 12 Rig.2 U 7