Abstract: Fuel injection control methods and systems and related apparatus for Liquefied Petroleum gas Injection (LPI) engine are provided. Preferred methods and systems determine the increased amount of engine revolution per unit time and fuel temperature during an initial engine start period; determine fuel pressure on the basis of such values; determines propane content of the engine fuel by consideration of the fuel pressure and fuel temperature of the P-T diagram of the fuel; and controls the fuel injection time and injection period by using a map prepared according to propane content. Preferred systems and methods of the invention need not include use of fuel pressure and temperature sensors that provide injection control conditions to an Engine Control Unit, thereby providing a simplified and more efficient apparatus.

Abstract: Fuel injection control methods and systems and related apparatus for Liquefied Petroleum gas Injection (LPI) engine are provided. Preferred methods and systems determine the increased amount of engine revolution per unit time and fuel temperature during an initial engine start period; determine fuel pressure on the basis of such values; determines propane content of the engine fuel by consideration of the fuel pressure and fuel temperature of the P-T diagram of the fuel; and controls the fuel injection time and injection period by using a map prepared according to propane content. Preferred systems and methods of the invention need not include use of fuel pressure and temperature sensors that provide injection control conditions to an Engine Control Unit, thereby providing a simplified and more efficient apparatus.