라디칼 인젝터를 적용한 연소시스템에서 부연소실의 신기유입 특성에 관한 계산적 연구

Abstract

Automobile technologies for high performance have been developed since automobile appeared about 100 years ago. Among the technologies, the engine technology is one of the critical technologies. Especially high technology for engine combustion concentrating on the reduction of CO2 appears nowadays.

Diesel engine used in the present time has many problems on environmental pollution, and gasoline engine is also has some problems on thermal efficiency and CO2 emission. Therefore, developing the novel technology to solve the problems from both type of engines, which are reducing energy consumption and exhaust emissions.

To correspond to this trend, homogeneous charged compression ignition (HCCI) engine has studied to supplement the existing diesel and gasoline engine. Various kinds of research about homogeneous charged compression ignition engine are performed but HCCI engine is just in the beginning because there are some problems about control of power generating and combustion timing.

To complement the defects of HCCI engine, HCCI engine having a radical injector is proposed. There are two chambers in the HCCI engine having a radical injector and a large quantity of radical from sub-chamber is injected to main chamber instantaneously and inducing self ignition on multi-points that makes homogeneous profile in lean mixture and performs rapid combustion at the same time. The performance of radical injector brings high thermal efficiency and reduces harmful exhaust gases at the same time.

Although radical injector has several merits, there are several problems. One of them is predicted as characteristics of the gas flow through narrow cylindrical connectors between main chamber and sub-chamber. Therefore, computer simulation under various geometries is important to predict characteristics of the gas flow that greatly effects on the next combustion process.

In this thesis, the characteristics of gas flow according to the number, shape of the connecters and the engine speed are simulated using KIVA-3V code.

The result shows that the gas inflow and outflow are greatly effected from the shape of connectors, which will be considered as a important design factor.