MULTIFUEL INTERNAL-COMBUSTION ENGINE

To improve an ignitability to a fuel having a low compressed ignitability in a combustion chamber (CC) in a compressed self-ignition diffusive combustion mode operation. In a multi-fuel internal combustion engine operated by introducing at least one type of fuel among at least two types of fuels (F1, F2) having different properties into a combustion chamber (CC) or introducing a mixed fuel composed of at least the two types of fuels (F1, F2) into the combustion chamber (CC), an electronic control unit (1) is provided with a fuel characteristics detection means that detects an ignitability index value as an index showing a compressed ignitability of a fuel itself introduced into the combustion chamber (CC), and a fuel injection control means that previously injects, when a compressed self-ignition diffusive combustion is performed using a fuel in the combustion chamber, which is determined to have a low compressed ignitability based on the ignitability index value, the fuel at a predetermined timing in a period from an intake stroke to a compression stroke, and thereafter mainly injects the fuel and introduces the fuel having the low compressed ignitability into the combustion chamber (CC).