International Journal

Title59. Kitae Yeom and Choongsik Bae, "Knock Characteristics in LPG-DME and Gasoline-DME Homogeneous Charge Compression Ignition Engines", Energy and Fuel, vol. 23, No. 4, pp1956-1964, 2009 (SCI; IF 2.319, citation : 2).

The knock characteristics in an engine were investigated under homogeneous charge compression ignition (HCCI) operation. The high load operation of HCCI engine is limited by knock and high combustion pressure. In order to avoid the engine damage, the engine must be operated under knock limit. Liquefied petroleum gas (LPG) and gasoline were used as fuels and injected at the intake port using port fuel injection equipment. Di-methyl ether (DME) was used as an ignition promoter and was injected directly into the cylinder during the intake stroke. A commercial variable valve timing device was used to control the volumetric efficiency and the amount of residual gas. Different intake valve timings and fuel injection amounts were tested to verify the knock characteristics of the HCCI engine. The intake valve open timing was varied from -29 to 11 crank angle degree after top dead center. The valve open duration was fixed at 228 crank angle degree. The λTOTAL was varied from 2.91 to 2.12 while, λDME was fixed at 3.7. The ringing intensity (RI), which indicates the energy of pressure wave, was used to define the intensity of knock according to the operating conditions. The RI of the LPG-DME HCCI engine was lower than that of the gasoline-DME HCCI engine through all the experimental conditions. The indicated mean effective pressure dropped when the RI was over 0.5 MW/m2 and the maximum combustion pressure was over 6.5 MPa. There was no substantial relationship between RI and fuel type. The RI can be predicted by measuring and calculating the crank angle degree of 50% mass fraction burned. Carbon monoxide and hydrocarbon emissions were minimized at high ringing intensity conditions. The shortest burn duration under 0.5 MW/m2 of RI was effective in achieving low hydrocarbon and carbon monoxide emissions.

Previous58. Kitae Yeom, Jungseo Park, Choongsik Bae, Jeongnam Park and Sungkun Kim, “The Anti-Vapor Lock of a Top-Feed Injector for a Liquefied Petroleum Gas Liquid Phase Injection Engine”, Energy and Fuel, vol. 23, No. 2, pp876-883, 2009 (SCI; IF 2.319, citation : 2).
Next60. Jinyoung Jang, Kiseon Yang, Kitae Yeom, Choongsik Bae, Seungmook Oh and Kernyong Kang, “Improvement of DME HCCI Engine Performance by Fuel Injection Strategies and EGR,” SAE International Journal of Fuel and Lubricants, ), vol. 117, No. 4, 1075-1083, (Paper No. 2008-01-1659), 2009 (citation : 8)
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