Low-heat-dissipation combined-structure piston

Abstract

The invention provides a low-heat-dissipation combined-structure piston which comprises a piston steel top, a thermal insulation cushion, an independent ring base, a positioning ring, an aluminum body, a bush, bolts, a gasket set and a locking nut, wherein the piston steel top, the thermal insulation cushion and the aluminum body are successively connected by bolts; a first ring base of the pistonhas an independent ring base structure and is installed on the top end of the aluminum body, and is compressed by the piston steel top and the thermal insulation cushion; and an air-seal thermal insulation cavity is formed between a concave structure on the middle of the piston steel top and the aluminum body, a stop hole is formed in the outer side at an outward extension part of the concave structure of the piston steel top, and the positioning ring is disposed between the thermal insulation cushion at the stop hole and the aluminum body. The piston provided by the invention has the beneficial effects that thermal transfer of the piston top to the aluminum body is isolated effectively; and thermal insulation is realized through three forms including air thermal insulation, physical thermal insulation with the low-heat-dissipation metal cushion, and combined structure contact thermal resistance, so the temperature of the aluminum body is controlled within a rational scope, and mechanical properties do not get degenerated greatly.

Description

Technical field [0001] The invention belongs to the technical field of engine pistons, and particularly relates to a piston with a low heat dissipation combined structure. Background technique [0002] At present, four-stroke diesel engines mostly use cast aluminum pistons to reduce the mass of the piston and reduce the reciprocating inertia force of the piston. However, the limit temperature that the cast aluminum piston can withstand is lower, about 420 degrees, and the combustion pressure of the engine continues to increase. , The temperature that the piston bears continues to rise, and the cast aluminum piston can no longer withstand such a high temperature, which can easily lead to piston ablation. [0003] To solve the above problems, there are generally three ways: [0004] One is the combined piston with a steel top and aluminum skirt. A cooling oil passage is set between the piston top and the aluminum body. During operation, the temperature of the piston top and the alumin...

AI Technical Summary

Problems solved by technology

[0005] The second is to adopt a steel top aluminum skirt heat insulation structure, which adds a metal heat insulation pad between the piston top and the aluminum body. The piston top is made of heat-resistant steel, and the heat transfer from the piston top to the aluminum body is reduced through the metal heat insulation pad. , so as to reduce the temperature of the aluminum body and save the cooling oil passage structure. Although the piston top of this type of structure can withstand higher temperatures, the heat insulation capacity of the metal heat insulation pad is limited and the overall mass is relatively large;

[0006] The third is to spray a heat-insulating coating on the top surface of the overall aluminum piston to reduce the heat transfer from the combustion chamber to the piston and reduce the surface temperature of the piston. However, the heat-insulating coating is easily affected by the thermal deformation of the piston. Problems such as cracking and falling off occur, and its reliability problem is still difficult to solve

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