Die-cast air cylinder cover of air-cooled single-cylinder diesel engine

Abstract

The invention relates to a die-cast air cylinder cover of an air-cooled single-cylinder diesel engine. The pattern drafts of an air-inlet channel cast hole segment and an air-outlet channel cast hole segment are both smaller than 3 percent; the air-inlet channel cast hole segment and the air-outlet channel cast hole segment are geometrically intersected with an air-inlet channel processed hole and an air-outlet channel processed hole to form curved channels of an air-inlet channel and an air-outlet channel; the maximum sizes of the cross sections of the air-inlet channel cast hole segment and the air-outlet channel cast hole segment at the geometrically intersected part are respectively equal to the diameters of the air-inlet channel processed hole and the air-outlet channel processed hole; the distances between the bottom surface of the air-inlet channel processed hole and the lower end surface of an air-inlet valve pilot hole as well as between the bottom surface of the air-outlet channel processed hole and the lower end surface of an exhaust valve pilot hole are 0-3mm; the cross-section areas of the intersected parts of the air-inlet and the air-outlet channel cast hole segments and the air-inlet and the air-outlet channel cast hole segments are maximum; the included angles between the axis of the air-inlet channel cast hole segment and the mounting surface of the air cylinder cover as well as between the axis of the air-outlet channel cast hole segment and the mounting surface of the air cylinder cover are 20-45 DEG; and compared with the traditional air cylinder cover of the 170F diesel engine, the die-cast air cylinder cover has the advantages that: the flow coefficients of the air-inlet channel and the air-outlet channel are increased by 15-23 percent, the power output is increased by 8-11 percent, the fuel consumption is reduced to 2-6 percent, air is exchanged thoroughly, and pollutants discharged by the diesel engine can be reduced.

Description

technical field [0001] The invention relates to a single-cylinder air-cooled diesel engine, in particular to a cylinder head of the single-cylinder air-cooled diesel engine. Background technique [0002] Single-cylinder off-road diesel engines play an important role in agricultural production. They are the main power source of agricultural machinery such as small and medium-sized tractors, miniature farming machinery, drainage and irrigation machinery. In the past five years, the annual production and sales have been around 7 million units. The design of intake and exhaust ports is an important aspect in the design of diesel engine cylinder head. In a diesel engine, the air flow into the cylinder and the appropriate swirl ratio have an important impact on the power, economy and emission performance of the internal combustion engine. At present, there are many researches at home and abroad on the swirl air passage of the intake swirl of the direct injection combustion diesel...

AI Technical Summary

Problems solved by technology

Through the research and analysis of the existing 170F diesel engine air passage, it is found that the cross section of the air passage is circular. Since the vertical part of the air passage in the direction of the valve guide needs to be machined, the air passage is formed into a cylinder after forming, and the intake and exhaust passages are at the valve guide. Generally, there is a turning passage. The die-casting core-pulling process requires high requirements, and the cross-sectional shape cannot be changed. At least the cross-sectional area of ​​the turning is the smallest. The cast air passage connected to the intake and exhaust pipes is parallel or slightly inclined to the bottom surface of the cylinder head. Due to the draft, the casting part and the vertical machining part of the valve end have a small flow section at the intersection of the turn, and sharp corners are formed on the lower edge of the intersection section, the flow performance is poor, and the area is reduced by as much as about 50%, resulting in poor performance of the diesel engine. Difference

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