RU2381375C2 - Internal combustion engine piston seal - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: internal combustion engine comprises cylinder, piston, upper and lower compression rings arranged in one piston groove. Note here that upper ring top edge seats at an acute angle to its lower edge to make upper ring larger vertical side face the cylinder axis, aid angle varying from 15° to 25°.

EFFECT: higher-efficiency seal.

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Description

The invention relates to mechanical engineering, and specifically to the design, manufacture and operation of internal combustion engines.

Known piston seals consisting of individual elements installed in one piston groove (UK application No. 20022874, 1979; US patent No. 4236723, 1982; Japan application No. 58-53186, 1983; RU 2244145 C2, 08.10.2003).

A piston seal for an internal combustion engine is known, containing two working rings installed in one piston groove, the upper end of the upper compression ring being made at an acute angle to its lower end, and the greater vertical side of the upper compression ring facing the axis of the cylinder, closest in technical essence and adopted for the prototype (US patent No. 1527535, IPC F16J 9/20, publ. 24.02.1925).

The prototype has a significant drawback, which consists in the fact that the upper trapezoidal compression ring, having an angle of inclination of the upper end and the upper flange of the piston groove less than the angle of self-braking of the wedge pairs, or loses its operability and operability of the underlying compression ring, guaranteed to jam both rings in the piston groove. Loss of mobility of the piston ring and its jamming in the piston groove first cause scratches and scoring on the cylinder wall, and then the piston seizes in the cylinder and engine breaks. This is one of the reasons leading to early overhaul, for example, KamAZ engines, in which the upper compression ring has the shape of a double-sided trapezoid with an angle of 6 °, and the lower compression ring has a single-sided trapezoid with an angle of 7 °. It should also be noted that the use of trapezoidal piston rings with similar angles of inclination of the ends of the piston rings is widely used in domestic and foreign diesel engineering practice.

The technical result, the achievement of which the invention is directed, is to increase the power and resource of the engine, reduce fuel and oil consumption, improve the environmental performance of the engine.

The technical result is achieved by the fact that in the piston seal for the internal combustion engine containing two compression rings installed in one piston groove, the upper end of the upper compression ring is made at an acute angle to its lower end, and the upper vertical ring faces the cylinder axis with the greater vertical side , new is that the angle of inclination of the upper end of the upper compression ring with respect to its lower end is 15 ... 25 °.

When calculating the angle of inclination of the upper end of the upper compression ring, the "self-braking ability" of the wedge pair is taken into account (Machine tools. Handbook. T.1. A.I. Astakhov, S.V. Boyarshinov, B.N. Vardashkin, etc. M .: Engineering, 1984, p. 400). Moreover, the critical value of the self-braking angle of such kinematic systems was taken into account: "... to ensure reliable self-braking, the angle α <5 ° 30 '... is recommended."

To exclude the guaranteed self-braking of the upper compression ring and jamming it in the piston groove, the angle of inclination of the upper end of the upper compression ring to its lower end is set to more than 5 ° 30 '. Moreover, when determining the angle of inclination of the upper end face of the upper compression ring, factors affecting its size are taken into account: materials of rings and pistons, roughness classes of contact surfaces, the possibility of soot and soot, and then carbon and coke on the surfaces of rings and piston grooves, overall dimensions of the structure and dynamic characteristics of the engine. On this basis, it is recommended that piston seal developers using a trapezoidal shape of piston rings, depending on the characteristics of the engine, use the angle of inclination of the upper end face of the upper piston ring and the upper piston groove flange within 15 ... 25 °.

A precisely calculated angle of inclination of the upper end face of the upper compression ring will increase the engine resource and ensure its trouble-free operation.

The drawing shows a partial section of an internal combustion engine.

The internal combustion engine comprises a cylinder 1, a piston 2, an upper compression ring 3 and a lower compression ring 4 mounted in the upper piston groove 5, the upper end of the upper ring 3 being made at an acute angle to its lower end so that the upper ring 3 faces a larger vertical side to cylinder axis 1.

The piston seal operates as follows. When the piston 2 moves to the upper position on the “compression” stroke, an insignificant part of the working pressure is throttled through the vertical part of the gap in the lock of the wedge-shaped ring 3 into the bottom cavity of the piston groove 4, creating, together with the elastic forces of rings 3 and 4, additional radial forces to expand them, realizing a reliable clamping of the rings to all contact surfaces of the cylinder 1 and the shelves of the piston groove 5. Moreover, as the piston 2 moves to the top dead center, the diameter of the upper part of the cylinder 1 increases as a result those thermodynamic changes and its more active wear. The compression rings 3 and 4 are unclenched, tracking the profile of the cylinder liner 1, tightly pressing against its wall, providing a reliable seal between the piston 2 and cylinder 1. The calculated angle of inclination of the upper end of the upper compression ring 3 ensures its mobility relative to the upper shelf of the piston groove 5 and the upper end lower compression ring 4 and eliminates their jamming.

When the piston 2 moves to the lower position at the “stroke” stroke, the compression rings 3 and 4 are forced to compress by the reaction forces from the side of the cylinder wall, moving deeper into the piston groove 5. The calculated angle of the upper end face of the upper compression ring 3 provides mobility of the ring 3, and together with it and the rings 4 in the piston groove 5 and eliminates their jamming.

At the “discharge” working cycle, the piston seal works like a “compression” cycle, and at the “inlet” working cycle it repeats the work on the “working stroke” cycle.

Thus, a correctly calculated angle of inclination of the upper end face of the upper compression ring will increase the engine resource, eliminate jamming of the compression rings and piston, and ensure trouble-free operation of the engine.

Claims (1)

A piston seal for an internal combustion engine containing two compression rings installed in one piston groove, the upper end of the upper compression ring being made at an acute angle to its lower end, and with the greater vertical side, the upper compression ring facing the axis of the cylinder, characterized in that the angle of inclination the upper end of the upper compression ring with respect to its lower end is 15 ... 25 °.

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