A Piston Structure Realizing Variable Compression Ratio of Engine

Abstract

A piston structure for realizing a variable compression ratio of an engine, including a piston pin seat with a piston pin seat hole inside, a cylindrical piston pin fully floating in the piston pin seat hole; a plate spring body installed in the piston pin seat hole In the piston pin, the two ends of the piston pin are respectively provided with inner retaining rings, and the outer sides of the two inner retaining rings are respectively provided with leaf spring pressing blocks. in the piston pin housing with a gap between the top of the piston pin and the top of the piston pin housing △h， gap △h The size determines the upper limit and lower limit of the variable compression ratio; the outer retaining rings are arranged on the outer sides of the two ends of the plate spring body; the outer side of the piston pin is fixedly equipped with a connecting rod. The invention has a simple structure, and can effectively change the compression ratio of the engine through the deformation of the plate spring body, so that the engine has good power performance, fuel economy and emission under different load conditions.

Description

technical field [0001] The invention relates to an automobile piston engine, in particular to a piston structure for realizing a variable compression ratio of the engine, which is suitable for a gasoline engine and an aviation piston engine. Background technique [0002] The compression ratio of an engine refers to the ratio of the internal volume of the cylinder when the piston is at the bottom dead center to the internal volume of the cylinder when the piston is at the top dead center, and is also the ratio of the total working volume of the cylinder to the volume of the combustion chamber. Increasing the compression ratio will increase the thermal efficiency of the engine . [0003] At present, gasoline engines are mostly used as power devices for passenger car engines in the world. Due to the low cost, high power per liter, light weight and easy after-treatment of exhaust gas, the gasoline engine will still be the main power unit of passenger cars for a long time in the...

AI Technical Summary

Problems solved by technology

[0010] At present, there are many technical solutions and related patents for the realization of the variable compression ratio of engines at home and abroad, but most of them have complex mechanical structures, difficult numerical control of variable compression ratios, difficult to solve dynamic balance, and increase the volume and weight of the engine. , which greatly increases the difficulty and cost of its development

For example, the French MCE5 variable compression ratio engine, due to the use of a new structure such as crankshaft, connecting rod, piston and hydraulic controller, has invested as many as one billion euros in the development of new parts and a large number of related products due to the difficulty of development. Compared with the traditional engine, the Saab SVC variable compression ratio engine is divided into upper and lower parts. The upper part is composed of a cylinder head and five cylinders. , the lower part is composed of the crankcase, crankshaft and piston of the engine. The integral cylinder head can rotate around the crankcase. Because the mass of the rotatable part of the engine is large, its rotation requires a lot of energy, and at the same time makes the volume of the engine In addition, the multi-link system VCR engine adopted by Japan's Nissan Company increases the overall size and vibration of the engine, and the friction loss increases correspondingly due to the increase of movable parts.

Due to the lack of practicability of the existing technology for realizing the variable compression ratio of engines, only prototypes have been developed and cannot be commercialized. So far, no passenger cars equipped with variable compression ratio engines have been mass-produced and sold.

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