In the given article, the results of the tribological research of the chrome-gray cast iron coupling are presented, the friction conditions between the cylinder liner and the compression segment being lubricated in various environments are modeled: diesel (control), pure biodiesel B100 and biodiesel-diesel B20 mixture. It was established that the average values of the coefficient of friction in the chrome-gray cast iron coupling, in the case of using biofuels B20, B100 as the lubricating material, are higher in relation to diesel fuel: by 15.6% for B20 and, respectively, by 23.3% for B100. The values of the total wear of the tribological coupling decreased, in relation to diesel, by 36.8% in the case of lubrication with B20 and by 39.5% - with B100.