직접분사식 LPG 기관기술은 두 가지 이상의 기술을 복합하여 기관효율을 최대화 할 수 있는 장래 기술로 판단된다. 하지만 기존 상용 디젤기관에 직접분사식 LPG기술의 접목은 많은 기술적 문제점이 발생한다. 따라서 본 연구에서는 디젤기관 고유의 자기착화방식에 실린더 내 직접분사식 LPG기술을 복합한 압축착화방식(LPDi ; LPG Direct Injection)을 사용하였다. 먼저 고압(25MPa)분사를 위해 무 윤활방식의 고압펌프를 사용하였으며, ...
직접분사식 LPG 기관기술은 두 가지 이상의 기술을 복합하여 기관효율을 최대화 할 수 있는 장래 기술로 판단된다. 하지만 기존 상용 디젤기관에 직접분사식 LPG기술의 접목은 많은 기술적 문제점이 발생한다. 따라서 본 연구에서는 디젤기관 고유의 자기착화방식에 실린더 내 직접분사식 LPG기술을 복합한 압축착화방식(LPDi ; LPG Direct Injection)을 사용하였다. 먼저 고압(25MPa)분사를 위해 무 윤활방식의 고압펌프를 사용하였으며, 세탄 첨가제를 조건별 혼합하였다. 또한 실린더 내에 직접 분사하여 분무 및 연소현상을 관찰하기 위해 먼저 수소와 산소 질소를 예혼합 연소시켜 디젤기관과 비슷한 고온 고압의 분위기 조건을 형성하였으며, 압축착화 방식의 연소를 위해서 세탄향상제인 DTBP(Di-Tert-Butyl Peroxide)를 5, 10, 15wt%의 비율로 LPG와 혼합하여 각 온도 조건에서의 화염의 확산과 착화지연 등의 연소특성을 파악하였다.
직접분사식 LPG 기관기술은 두 가지 이상의 기술을 복합하여 기관효율을 최대화 할 수 있는 장래 기술로 판단된다. 하지만 기존 상용 디젤기관에 직접분사식 LPG기술의 접목은 많은 기술적 문제점이 발생한다. 따라서 본 연구에서는 디젤기관 고유의 자기착화방식에 실린더 내 직접분사식 LPG기술을 복합한 압축착화방식(LPDi ; LPG Direct Injection)을 사용하였다. 먼저 고압(25MPa)분사를 위해 무 윤활방식의 고압펌프를 사용하였으며, 세탄 첨가제를 조건별 혼합하였다. 또한 실린더 내에 직접 분사하여 분무 및 연소현상을 관찰하기 위해 먼저 수소와 산소 질소를 예혼합 연소시켜 디젤기관과 비슷한 고온 고압의 분위기 조건을 형성하였으며, 압축착화 방식의 연소를 위해서 세탄향상제인 DTBP(Di-Tert-Butyl Peroxide)를 5, 10, 15wt%의 비율로 LPG와 혼합하여 각 온도 조건에서의 화염의 확산과 착화지연 등의 연소특성을 파악하였다.
Modern engine technology to meet emission regulations for global warming and environmental pollution can be classified by the technology of direct injection type engine, direct injection type small size diesel engine and alternative fuel engine. Among these, direct injection type engine technology h...
Modern engine technology to meet emission regulations for global warming and environmental pollution can be classified by the technology of direct injection type engine, direct injection type small size diesel engine and alternative fuel engine. Among these, direct injection type engine technology has been effective in improving an air-fuel ratio and efficient emission reduction and also alternative fuel engine technology does well in the reduction of emission. Combining such a two technology may suggest the solution of environmental pollution problems due to stringent emission regulation. In particular, direct injection type LPG engine technology has been known to a promising technology which engine efficiency can be maximized. However, the application of direct type LPG technology to a present diesel engine cause problems technologically. Therefore, in this research liquefied petroleum direct injection (LPDI) type was applied by the combination of direct injection type LPG technology with intrinsic autoignition of a diesel engine. For the high pressure (25MPa) injection, an air driven liquid high pressure pump was used and cetane enhancer was added according to the experimental conditions. In addition, first of all, hydrogen, oxygen and nitrogen were premixed and ignited and then provided high temperature and pressure similar to one in a diesel engine in order to investigate spray and combustion phenomena inside of a constant volume chamber. For the combustion of compressed ignition cetane enhancer DTBP(di-tert-butyl peroxide) was added to LPG fuel with the ratios of 5, 10, 15wt% and combustion characteristics of flame diffusion and ignition delay were investigated. After such a experiment was conducted, followings were obtained. 1) As the result of spray experiment of liquid LPG fuel, penetration force against fuel evaporation and ambient high pressure inside cylinder was decreased drastically when the ambient conditions of high temperature and pressure were provided. The time to reach a cylinder wall was shorten and the penetration force was week when injection pressure was increased. 2) Unlikely to diesel fuel, the ignition of LPG fuel was started from the top of spray because fast evaporation and mixture with ambient air was done efficiently after the injection of LPG fuel. 3) From the result of combustion pressure and heat release rate, the duration of ignition was reduced due to the effect of higher cetane values when the ratios of addition were increased. 4) When ambient temperature of inside a constant volume chamber and addition ratio of cetane enhancer were increased, CO and unburned HC emission decreased but CO₂ emission increased due to improvement of ignition and desirable combustion.
Modern engine technology to meet emission regulations for global warming and environmental pollution can be classified by the technology of direct injection type engine, direct injection type small size diesel engine and alternative fuel engine. Among these, direct injection type engine technology has been effective in improving an air-fuel ratio and efficient emission reduction and also alternative fuel engine technology does well in the reduction of emission. Combining such a two technology may suggest the solution of environmental pollution problems due to stringent emission regulation. In particular, direct injection type LPG engine technology has been known to a promising technology which engine efficiency can be maximized. However, the application of direct type LPG technology to a present diesel engine cause problems technologically. Therefore, in this research liquefied petroleum direct injection (LPDI) type was applied by the combination of direct injection type LPG technology with intrinsic autoignition of a diesel engine. For the high pressure (25MPa) injection, an air driven liquid high pressure pump was used and cetane enhancer was added according to the experimental conditions. In addition, first of all, hydrogen, oxygen and nitrogen were premixed and ignited and then provided high temperature and pressure similar to one in a diesel engine in order to investigate spray and combustion phenomena inside of a constant volume chamber. For the combustion of compressed ignition cetane enhancer DTBP(di-tert-butyl peroxide) was added to LPG fuel with the ratios of 5, 10, 15wt% and combustion characteristics of flame diffusion and ignition delay were investigated. After such a experiment was conducted, followings were obtained. 1) As the result of spray experiment of liquid LPG fuel, penetration force against fuel evaporation and ambient high pressure inside cylinder was decreased drastically when the ambient conditions of high temperature and pressure were provided. The time to reach a cylinder wall was shorten and the penetration force was week when injection pressure was increased. 2) Unlikely to diesel fuel, the ignition of LPG fuel was started from the top of spray because fast evaporation and mixture with ambient air was done efficiently after the injection of LPG fuel. 3) From the result of combustion pressure and heat release rate, the duration of ignition was reduced due to the effect of higher cetane values when the ratios of addition were increased. 4) When ambient temperature of inside a constant volume chamber and addition ratio of cetane enhancer were increased, CO and unburned HC emission decreased but CO₂ emission increased due to improvement of ignition and desirable combustion.
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