Use of fuel injection equipment with increased injection pressure for reducing environmental footprint

BACKGROUND: Environmental pollution causes a number of irreversible consequences, including those associated with climate warming, acid precipitation, deterioration of climatic conditions and others. The problem of reducing harmful emissions of diesel engines containing in exhaust gases is currently relevant, as the implementation of the EURO 4/5/6 standards is becoming increasingly difficult for both new automotive equipment and those already in operation.

AIMS: Reduction of harmful emissions into the atmosphere and reduction of environmental footprint by increasing the fuel injection pressure in a diesel cylinder.

MATERIALS AND METHODS: The 6Ch15/18 (7D6-150) diesel engines, having nominal power of 110 kW at 1500 min^-1, specific effective fuel consumption of 224 g/(kWh) and oil burn of 0.32% of the fuel consumption intended for diesel generator units, were tested. During steady-state tests, diesel exhaust gases were collected to analyze their composition and determine the dispersion of solid particles (SP) with an increase in fuel injection pressure by tightening the nozzle springs.

RESULTS: It was revealed that with an increase in the tightening of the nozzle springs and an increase in the injection pressure (P_I), emissions of solid particles with exhaust gases decrease, and the fuel efficiency of diesel increases. As a result of the tests carried out, it was found that with an increase in the springs tightening of the injectors from (P_I increased from 160 to 185 kPa), emissions of nitrogen oxides (NO_x) decreased by 15%, emissions of carbon monoxide (CO) decreased by 15%, emissions of hydrocarbons (C_xH_y) decreased by 54% and emissions of solid particles (SP) decreased by 33%. Improved mixing and better preparation of fuel for combustion explain the change in CO emissions with the P_I increase. The emissions of C_xH_y indicate a significant improvement in the completeness of fuel combustion in the cycle. Emissions of solid particles containing in exhaust gases are reduced due to the intensification of mixing of air and fuel vapor, contributing to a more complete burn-off of soot in a cylinder. The C_xH_y emissions are reduced and meet the EURO-3 and EURO-4 standards. The environmental footprint was as follows: N_EF = 51.34 Сt/year at P_I = 160 kPa and N_EF = 43.66 Сt/year at P_I = 185 kPa, which indicates a decrease in the environmental footprint by 1.17 times or by 15%.

CONCLUSIONS: The practical value of the study lies in the possibility of using fuel injection equipment with increased fuel injection pressure into a cylinder to reduce harmful emissions from diesel exhaust gases down to the required standards.