The use of diesel oil and methanol mixture in a Diesel engine requires modernization of old fuel injection control systems or development of new ones. Therefore, few options of structural solutions of the fuel injection system have been developed. The objective of the paper was to develop a structure of control elements of fuel injection in a Diesel engine which works with diesel oil and methanol mixtures, diesel oil and biogas mixtures, to check their practical utility and formulate indications. The control systems of multi-fuel Diesel and gas engines as well as two types of submerged high-pressure regulators were discussed. Characteristics of engine power, torque, unit and hour fuel consumption in the function of rotational speed with the use of Diesel D-21A1 engine were defined. The impact of methanol addition to diesel oil on the power and other performance indexes of a Diesel engine were determined. Two structural variants of the submerged fuel regulator were positively evaluated. The described solutions obtained a patent right and a patent protection and have been introduced to production in the Flow Machines Unit in Nikopol (Russia) and are used by the Central Scientific and Research Institute of Diesel Fuels in Saint Petersburg with work on improvement of Diesel engines.