Investigation of Liquid LPG Injection System Applied to Gasoline Engines

The developments in internal combustion spark ignition (gasoline) engine technologies are in line with emission standards. The conversion systems which enable the use of LPG fuel in spark ignition (gasoline) engines renew themselves according to the developments in engine systems. Developments in LPG systems started with the application to carburetor engines and have continued with Single point injection (SPI) engine and multi-point injection (MPI) engine. Today, sequential LPG systems are used in MPI engines. In this system, the vehicle first operates with gasoline and automatically switches to LPG mode when the engine coolant reaches 250C. The liquid LPG system, which is the latest technology, is applied in direct injection gasoline engines. Since the liquid LPG system uses the vehicle’s own gasoline injectors and the evaporator is not available, the vehicle can operate directly in the LPG fuel position. That's why fuel economy and emissions standards are better. The aim of this study is to investigate the applications of currently used liquid LPG systems on new generation gasoline engines and to investigate their differences according to gasoline. In the study, the liquid LPG system used in the direct injection gasoline engines with the latest LPG systems was examined, the system was introduced and the problems of the previously used LPG systems were addressed.