At the present stage of development of engine manufacturing technology, the main normalized indicators of transport diesel engines are the exhaust gas toxicity indicators. An effective way of improving these indicators is the use of alternative fuels. Promising alternative fuels are considered to be biofuels derived from renewable vegetable raw materials. The paper considered the opportunity of using linseed, mustard, and camelina oils as ecological additives to petroleum diesel fuel. Experimental studies of an automobile diesel engine of type 4H 11/12.5 fueled with mixtures of petroleum diesel fuel blended with these vegetable oils were carried out. The volume fraction of vegetable oil in the blended fuels was up to 10%. A multicriteria method for optimization of the composition of vegetable oil-blended biofuels was proposed. Emissions of nitrogen oxides and soot from exhaust gases were considered as the main evaluation criteria of engine emission characteristics. The addition of 10% vegetable oil to petroleum diesel fuel allowed reducing nitrogen oxide emissions by 4-10% and smoke opacity by 11-16%. A decrease in the content of carbon monoxide in the exhaust gas by 5-15% and light unburned hydrocarbons by 11-17% was noted. When the diesel engine was fueled by the studied blends, the engine efficiency change did not exceed 3%.

Biofuels derived from renewable plant materials are considered promising alternative fuels to decrease emissions of ICEs. This study aimed to justify the possibility of using vegetable oils of different sources as a 10% additive in blended biofuel for diesel engines of agricultural machinery and commercial vehicles. Seven different vegetable oils were investigated. Experiments have been performed by fueling a diesel engine with blended biofuels of 90% petroleum diesel fuel and 10% vegetable oil. In the maximum power and maximum torque modes, the brake power drop was no more than 1.5%, and the brake-specific fuel consumption increase was less than 4.3%; NOx emissions were reduced by up to 8.3%, exhaust smoke—up to 37.5%, CO—up to 20.0%, and unburned HC—up to 27.9%. In the operating modes of the European 13-mode steady-state test cycle, the integral specific emissions of HC decreased by up to 30.0%, integral specific emissions of CO—up to 15.0%, and integral specific emissions of NOx—up to 16.0%. The results obtained show the feasibility and rationality of using the investigated vegetable oils as a 10% additive in blended biofuel for diesel engines of agricultural machinery and commercial vehicles.

The relevance of this article is due to the need for improving indicators of exhaust gas toxicity of diesel engines. One of the modern directions of achieving the required environmental performance of diesel engines is the addition of various nanomaterials to petroleum diesel fuel. The aim of the present study was to investigate the possibility of improving the environmental performance of a diesel engine for a generator set using carbon nanotubes as an additive to petroleum diesel fuel in an amount of up to 500 mg/L. Experimental studies were carried out on a D-243 diesel engine operating in a wide range of loads from idle to full load with the addition of 125, 250, and 500 mg/L of carbon nanotubes in the diesel fuel. The mixing of petroleum diesel fuel with nanotubes was done using an ultrasonic unit. The possibility of improving the environmental performance of the studied diesel engine fueled with carbon nanotube-blended petroleum diesel fuel was examined. Results showed that, in the full-load mode of diesel operation, the addition of 500 mg/L of carbon nanotubes to diesel fuel enabled the engine to reduce exhaust smoke from 26.0% to 11.2% on the Hartridge scale.

The article discusses the possibility of using blended biofuels from rapeseed oil (RO) as fuel for a diesel engine. RO blended diesel fuel (DF) and emulsified multicomponent biofuels have been investigated. Fuel physicochemical properties have been analyzed. Experimental tests of a diesel engine D-245 in the operating conditions of the external characteristic curve and the 13-mode test cycle have been conducted to investigate the effect of these fuels on engine performances. CFD simulations of the nozzle inner flow were performed for DF and ethanol-emulsified RO. The possibility of a significant improvement in brake thermal efficiency of the engine has been noted. The efficiency of using blended biofuels from RO as a motor fuel for diesel engines has been evaluated based on the experimental test results. It was shown that in comparison with the presence of RO in emulsified multicomponent biofuel, the presence of water has a more significant effect on NOx emission reduction. The content of RO and the content of water in the investigated emulsified fuels have a comparable influence on exhaust smoke reduction. Nozzle inner flow simulations show that the emulsification of RO changes its flow behaviors and cavitation regime.