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조우흠,이형승,김응서 대한기계학회 1995 대한기계학회논문집 Vol.19 No.7
Owing to the serious problem of hydrocarbon fuel such as environmental pollution, the development of alternative fuel is very urgent. To adopt hydrogen to the internal combustion engine, a solenoid-drive type in-cylinder injection system was constructed. The injection system was installed to the single cylinder research engine, and the engine performance and the emission of citric oxide were tested upon the fuel-air equivalence ratio and the spark timing. In the case of in-cylinder injection system, hydrogen is injected after the intake valve is close, so it is possible to operate the engine without the back fire and the fall of its volumetric efficiency. In the region of the fuel-air equivalence ratio below 0.5, hydrogen and air aren't well mixed and the thermal efficiency is lowered, so the nozzle should be designed to inject hydrogen uniformly into the combustion chamber. In the region of the fuel-air equivalence ratio above 0.7,the fuel-air mixture burns very fast and the amount of citric oxide emission increases rapidly, so the spark timing should be retarded as compared with MBT.
강종민,안기환,조우흠,권몽주 한국소음진동공학회 1997 소음 진동 Vol.7 No.6
Combustion oriented noise is a part of engine noise, which is mainly determined by the in-cylinder pressure profile and the structure attenuation of an engine. A numerical model for predicting the in-cylinder pressure profile and the resultant combustion noise developed by the use of a commercial code. The model is experimentally validated and updated based on the performance as well as the noise by considering the fuel injection timing, the fuel injection rate, Cetane number, intake temperature, and compression ratio. For providing a design guide of a fuel injector for a low combustion noise engine model, the optimal parameters of injection pressure profile, injection rate profile, and injection timing are determined, which gives the 5 dBA noise reduction.
강종민,안기환,박해성,조우흠 한국소음진동공학회 1997 소음 진동 Vol.7 No.5
The well-developed noise separatrion techniques are applied to the V8 RG8 Diesel engine for the engine noise reduction of a commercial vehicle. For various loads and engine RPM's, the contribution of the combustion oriented noise and the mechanically induced noise was calculated under the small variations of the injection timing. For the given Diesel engine the mechanical noise is dominant for low rpm, and the contribution of the combustion noise becomes greater as the rpm increases. The combustion noise is dominant around 2kHz range or under 50% loading condition.