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.

Comparative experimental studies of fuel sprays evolution dynamics in a constant volume chamber were carried out with a view to reduce the uneven distribution of diesel fuel in the combustion chamber when the Common Rail injector is inclined. The fuel sprays was captured by a high-speed camera with simultaneous recording of control pulses of camera and injector on an oscilloscope. Two eight-hole diesel injectors were investigated: One injector with identical orifice diameter (nozzle 1) and another injector with four orifices of the same diameter as orifices of nozzle 1 and four orifices of enlarged diameters (nozzle 2). Both injectors were tested at rail pressure from 100 to 165 MPa and injector control pulse width of 1.5 ms. The dynamics of changes in the spray penetration length and spray cone angle were determined. It was found that sprays develop differently in nozzle 1 fuel. The difference in the length of fuel sprays is 10–15 mm. As for nozzle 2, the fuel sprays develop more evenly: The difference in length is no more than 3–5 mm. The difference of the measured fuel spray cone angles for nozzle 1 is 0.5°–1.5°, and for nozzle 2 is 3.0°–4.0°. It is concluded that the differential increase in the diameters of nozzle orifices, the axes of which are maximally deviated from the injector axis, makes it possible to reduce the uneven distribution of fuel in the combustion chamber and improve the combustion process and the diesel performance as a whole.

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.

Background/Objectives: The motor-less fuel stand has been described capturing high-speed video in the process of fuel jet development in Common Rail type injector. Methods: The experiments were carried out simultaneously recording the electric signals of the start and end moments of the electrical impulse controlling the injector with digital color oscilloscope Tektronix TDS-2014С and high-speed imaging of the fuel jet sprays with color video camera FASTCAM SA-X2. Findings: The delays of the start and termination of actual fuel injection that depend on the electrical impulse for the injector control have been determined and the dynamics of the fuel jet development has been observed under the fuel rail pressure from 100 to 165 MPa. The dependency of the duration of the fuel injection process on the duration of the electrical impulse controlling the injector has been established. Applications/Improvements: The results of the study can be used for diesel engine design and commissioning and for improving the shape of the combustion chamber to ensure better carburetion in the cylinder.