Engine capable of directly injecting natural gas for multiple times under high pressure in cylinder and layered rapid combustion method thereof

Abstract

The invention aims to provide an engine capable of directly injecting natural gas for multiple times under high pressure in a cylinder and a layered rapid combustion method thereof. The engine comprises an air cylinder cover, an air cylinder wall, a piston, an air inlet channel, an air inlet valve, an exhaust channel, an exhaust valve, a high-pressure natural gas injection valve, a high-pressure natural gas supply pipeline and a spark plug, wherein the cylinder cover, the cylinder wall and the spark plug form a combustion chamber, the combustion chamber is hemispherical, the air inlet channel,the exhaust channel, the high-pressure natural gas injection valve, the high-pressure natural gas supply pipeline and the spark plug are arranged in the cylinder cover, the high-pressure natural gassupply pipeline is connected with the high-pressure natural gas injection valve, the air inlet valve is arranged in the air inlet channel, the exhaust valve is arranged in the exhaust channel, and thehigh-pressure natural gas injection valve is located between the air inlet channel and the spark plug. The engine is advantaged in that layered combustion of different gradients under different loadscan be achieved, the ignition stability of the natural gas engine is guaranteed, economical efficiency and dynamic property of the engine are effectively improved, and emission is reduced.

Description

technical field [0001] The invention relates to an engine and its control method, in particular to a natural gas engine and its combustion control method. Background technique [0002] Since the birth of the first natural gas engine in the early 1930s, it has experienced three major developments: the first major development occurred after the Second World War. Petroleum fuels were very scarce, and most of them were used in wars. In order to solve fuel applications The problem is that people think of natural gas fuel at this time, so a large amount of natural gas fuel is used in stationary internal combustion engines, and some internal combustion engines for vehicles also use natural gas. Natural gas has been highly valued by various countries. [0003] Compared with the traditional out-of-cylinder premixing method, the advantages of gas direct injection in cylinder are: it can significantly reduce or eliminate the charge efficiency loss caused by gas fuel; avoid fuel loss du...

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Problems solved by technology

[0004] At present, research on the combustion characteristics of direct injection natural gas engines has been carried out at home and abroad. For example, a patent with the publication number CN201306206Y has applied for a lean stratified combustion chamber structure for a two-valve engine with direct injection natural gas in cylinders. A pit is set on the top of the piston. , in conjunction with the injection time and piston movement, the concentration of natural gas near the spark plug is relatively high, and an uneven gas mixture is formed during lean combustion. Although this patent improves the situation of stratified combustion of natural gas in low and medium working conditions, it cannot be applied For high-load working conditions; patent CN101749136A applied for an electronically controlled gas-in-cylinder direct-injection engine. CN109339943A applied for the combustion system of a natural gas in-cylinder direct-injection dual-fuel engine with a tumble flow combustion chamber, which adopts in-cylinder high-pressure direct-injection natural gas technology and micro-injection diesel ignition technology to realize dual-fuel combustion for different operating conditions of the engine. The fuel in the engine cylinder burns efficiently and cleanly; none of these patents proposes combustion optimization, gas injection, ignition and combustion chamber structure optimization matching methods for high-pressure direct injection natural gas engines in the cylinder under different operating conditions

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