The relevance of this study is due to the need to replace petroleum diesel fuel with motor fuels obtained from alternative raw materials. Rapeseed oil and ethyl alcohol are considered as promising alternative fuels. The use of these biofuels as a motor fuel makes it possible to solve the problem of reducing carbon dioxide emissions into the atmosphere and switch to carbon-neutral energy. The possibility of using mixtures of these fuels as motor fuel for a diesel engine is considered. Poor flammability of these fuels in the combustion chamber of a diesel engine was noted. The created installation allowing to carry out experimental studies of the ignition delay period of various fuels for diesel engines in the conditions of the engine stand is described. Four types of fuel were studied at this installation – petroleum diesel fuel, rapeseed oil, an emulsion of rapeseed oil and ethyl alcohol in a ratio of 90:10 and an emulsion of rapeseed oil and ethyl alcohol in a ratio of 70:30. The kinetic constants of ignition of these fuels have been determined. A significant dependence of the duration of the ignition delay period on the type of fuel used was noted.