Abstract: A dual fuel engine (2) is provided which is supplied with diesel fuel and at least one secondary fuel, such as LPG. The engine (2) has a plurality of cylinders (4, 6, 8, 10) in which pistons reciprocate. Each cylinder has diesel injectors (4A, 6A, 8A, 10A) for injecting the diesel fuel into the cylinder during an appropriate stroke of the piston and an air inlet valve (4C, 6C, 8C, 10C) which opens during the appropriate stroke of the piston to permit air flow therethrough. Each cylinder is further provided with LPG injectors (4B, 6B, 8B, 10B) for injecting the secondary fuel into the cylinders. The LPG injectors are independent to and separate from the diesel fuel injectors. The LPG and diesel fuel injectors are also independently controlled.