Han-Sub Sim

A study on the injection characteristics of a liquid-phase liquefied petroleum gas injector for air-fuel ratio control

Abstract Liquefied petroleum gas (LPG) is widely used as a gaseous fuel in spark ignition engines because of its considerable advantages over gasoline. However, the LPG engine suffers a torque loss because the vapour-phase LPG displaces a larger volume of air than do gasoline droplets. In order to improve engine power as well as fuel consumption and air-fuel ratio control, considerable research has been devoted to improving the LPG injection system. In the liquid-phase LPG injection systems, the injection rate of an injector is affected by the fuel temperature, injection pressure, and driving voltage. When injection conditions change, the air-fuel ratio should be accurately controlled in order to reduce exhaust emissions. In this study, correction factors for the fuel injection rate are developed on the basis of fuel temperature, injection pressure, and injector driving voltage. A compensation method to control the amount of injected fuel is proposed for a liquid-phase LPG injection control system. The experimental results show that the liquid-phase LPG injection system works well over the entire range of engine speeds and load conditions, and the air-fuel ratio can be accurately controlled by using the proposed compensation algorithm.

Experimental analysis of a liquid-phase liquefied petroleum gas injector for a heavy-duty engine:

Abstract Liquefied petroleum gas (LPG) is a well-known clean alternative fuel for vehicles. In a heavy-duty, liquid-phase LPG injection (LPLi) system, several factors influence the amount of fuel injected. These factors are fuel temperature, fuel injection pressure, battery voltage, and so on. In order to maintain the stoichiometric air-fuel ratio in the cylinder during engine operation, the injected fuel quantity should be controlled accurately. In this study, the characteristics of the injector used in the heavy-duty LPLi engine are investigated experimentally. The fuel injection algorithm, which compensates for the variations in the injection pressure, the fuel temperature and the battery voltage, is developed and verified through engine tests.

Study on Performance Evaluation and Efficiency Comparison for Solar Collector with Thermosyphon Tube-type

The use of solar energy among renewable energy tends to increase because of infinity and cleanness of resources. Even though the consumption rate of solar energy in our country is still low, however, in recent years, the research for solar energy have been widely conducted due to policy support of government. This study was performed to make the system of performance test for solar collector and to investigate thermal efficiency for solar collector with thermosyphon tube-type. As a result, in case of indoors measurement using halogen lamp, thermal efficiency for solar collector with thermosyphon tube-type was increased about 15~22% after 120 minutes compared with that of solar collector with double evacuated tube-type. In addition, in case of outdoors measurement, thermal efficiency of thermosyphon tube-type was showed maximum about 46% higher than double evacuated tube-type.