Patent RU-2747981-C1 (RU)
Title: Method for piston movement with infinitely small influence of shear deformation of connecting rod in cylinder of rotation
Inventor: Chigrik Nadezhda Nikolaevna
IPC: F02F3/00
Filed: 2020-08-26
Granted: 2021-05-18
Abstract: FIELD: internal combustion engines.  
     SUBSTANCE: invention can be used in reciprocating internal combustion engines. The method of piston movement consists in the fact that when the connecting rod returns to equilibrium when the piston is shifted at top dead center from one cylinder wall to another, the piston (3) rotates along the surface of the oblique open helicoid. The surface of an oblique open helicoid sets the motion of a rectilinear generatrix corresponding to the height of the piston, tangent to the cylindrical surface arising coaxially to the cylinder (4), with a skew (γ 1 ) of the piston (3) or in the common plane of mutually perpendicular axes of the cylinder (4) and the crankshaft (2), or in the plane of parallel skew of the cylinder axis (4) relative to the common plane of mutually perpendicular axes of the cylinder of rotation (4) and the crankshaft (2). The movement of the piston (3) is formed due to the presence of an operating clearance (Δ1), which is set by the radial runout tolerance along the inner surface of the cylinder (4) at the corresponding height of the piston (3). The operational clearance (Δ1) is formed by the difference between the largest and the smallest distance from the points of the real surface to the base axis within the limits of the normalized section of its path in the cylinder (4) limited by the piston (3) stroke. The movement is also formed parallel with a change in the twist angle (γ 3 ) of the piston (3) around the cylinder axis (4) of the generatrix of the guide cone with a slope angle at the apex (α') when the piston (3) passes at the moments of alignment along one straight line of the crankshaft crank radius (2) with the longitudinal axis of the connecting rod (1) from the bottom dead center is greater than the normalized section of its path limited by the piston stroke (3) by the sum of deviations of the piston stroke (3) from the primary deviations set by the axial displacement of the clearance of the guide cone (Δα'). Primary deviations arise when the piston (3) in the cylinder (4) is screwed from the skew of the piston (3) in the common plane of mutually perpendicular axes of the rotation cylinder (4) and the crankshaft (2), or in the plane of parallel transfer of the cylinder axis (4) relative to common plane of mutually perpendicular axes of the cylinder of rotation (4) and the crankshaft (2), with rotation around the axis of the cylinder (4) by the corresponding shear deformation of the connecting rod (1) not excluded component of the error of the angle (γ 3 ) of twisting of the piston (3) around the axis of the cylinder (four). The helical movement of the piston (3) on the surface of the oblique open helicoid within the limits of the normalized section of its path in the cylinder (4) limited by the stroke of the piston (3) is reduced to finding the projections of the helical lines formed by the movement of the boundary points corresponding to the height of the piston (3) by the rectilinear generatrix along its horizontal projection onto the plane P1. The formula contains mathematical expressions that explain the claimed method. 
     EFFECT: invention reduces the effect of shear deformation of the connecting rod in a three-link crank mechanism when it passes the normalized section of its path in the cylinder of rotation, limited by the piston stroke, which makes it possible to increase the reliability and durability of piston engines. 
     1 cl, 7 dwg