Experimental study on the icing characteristics of LPLi injectors under various injection conditions

Development of alternative fuels has been increasing to replace conventional fuels because of severe environmental pollution from the exhaust emissions of ground vehicles and the depletion of fossil fuels. LPG (Liquefied petroleum gas) fuel provides clean energy for gasoline-fueled engines and LPG fuel R&D (Research & development) has actively progressed in reaching the application stage. However, the icing phenomenon in liquid-phase LPG injection systems remains a major problem. The purpose of this study was therefore to investigate the temperature distribution on the icing protection tip and icing formation characteristics under various test conditions (i.e. injection pressure, injection frequency, injection duty). The results showed that increasing the injection frequency induced a big the temperature drop, whereas increasing the injection duty decreased the temperature drop under the same test conditions. Increasing the injection pressure caused a small temperature drop because of an increase in the injection velocity, which meant that much of the injected LPG evaporated at a region distant from the nozzle tip. The protection tip with a double-hollow structure had a smaller the temperature drop than the all-in-one type protection tip made of the same material (copper).