Gas passage and combustion chamber structure of three-valve engine

Abstract

The invention discloses a gas passage and combustion chamber structure of a three-valve engine. The inner roof wall of a combustion chamber (4) has a double-bevel structure, the included angle ranging from 120 degrees to 128 degrees is formed between a first bevel (4a) and a second bevel (4b), and an inlet end of a first gas inlet passage (1) and an inlet end of a second gas inlet passage (2) areconverged into a gas inlet passage section (5) with outer end orifice circular and inner end orifice elliptical. An inlet section of a gas exhaust passage (3) is a straight section with the diameter (L1) ranging from 17mm to 21mm, and outlet sections of the first gas inlet passage (1) and the second gas inlet passage (2) are also straight sections with the diameter (L2) ranging from 14mm to 18mm.After the gas inlet passages and the gas exhaust passage are optimized, the three-valve engine can realize gas feeding and exhausting more sufficiently and has higher combustion efficiency, and meanwhile, heat loss can be reduced and heat efficiency can be increased effectively.

Description

technical field [0001] The invention belongs to the technical field of engines, and in particular relates to the structure of an air channel and a combustion chamber of a three-valve engine. Background technique [0002] At present, small-displacement motorcycle engines all adopt a double-valve structure. This is because small-displacement motorcycle engines have relatively low performance requirements for medium and high speeds. Although the conventional double-valve engine is relatively noisy, it can meet the operating requirements. Require. With the continuous improvement of performance requirements, it has become a development trend to use three-valve engines on small-displacement motorcycles. The shape of the combustion chamber of the conventional three-valve engine is irregular, there are many steps in the combustion chamber, the airflow resistance is large, the flame propagation speed is low, and the heat transfer area is large, and the heat loss is large, resulting ...

AI Technical Summary

Problems solved by technology

The shape of the combustion chamber of the conventional three-valve engine is irregular, there are many steps in the combustion chamber, the air flow resistance is large, the flame propagation speed is low, and the heat transfer area is large, the heat loss is large, resulting in low thermal efficiency

At the same time, the unreasonable design of the intake and exhaust passages of the three-valve engine will lead to low intake flow coefficient, small intake tumble flow, and insufficient intake air, so that the movement speed of the mixed gas flow is slow; similarly, the exhaust flow coefficient Smaller, insufficient exhaust so the engine can't draw in as much fuel mixture

The above factors will affect the greater power output of the engine on the one hand, and on the other hand, will increase the energy consumption of the engine

Chinese patent ZL02113222.4 disclosed a three-valve engine combustion chamber on July 21, 2004. The combustion chamber is composed of a canopy and a spherical surface. Although it has the characteristics of simple manufacture, the power and torque are small, and the power is 5.6kw / 8500r / min, the torque is 7.2N.m / 6500r / min, and the noise of the valve is relatively large

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