| dc.description.abstract | The work is devoted to solving an urgent scientific and prac-tical task: establishing mathematical models that describe the effect of op-erating modes of diesel engines on the content in the exhaust gases of a dangerous pollutant – particulate matter (PM). The purpose of the work has been to create and study the accuracy and practical suitability of the calcu-lation method estimating concentrations and emissions with exhaust gases PM by means of mathematical modeling of the influence on them of param-eters that determine steady-state and unsteady diesel operation modes. The following research methods have been used in the work, such as: analysis and synthesis of information, mathematical modeling, experimental studies, and computational experiment. The studies have been carried out on the basis of the motor stand of a 4ChN12/14 autotractor diesel equipped with a partial-flow system for diluting EG with air – MKT-2 microtunnels. Mea-surements of mass and volume concentrations – cpt (g/kg) and Cpt (g/mn3), mass – PTmass (g/h) and specific – PTp (g/kWh) PM emissions have been carried out by the gravimetric method with errors of ± 3 .. 10% in accor-dance with the requirements of regulatory documents – ISO8178 standard, UNECE Rules R-49, R-96, etc. The parameters, which determine the mode of operation of the diesel engine, have been considered: during the studyof the steady-state modes – the number of revolutions of the engine crank-shaft (n, min-1) and the load (L,%); in the study of unsteady modes – the parameters n and L and the rate of change over time – Δn/Δt and ΔL/Δt. As a result of studying concentrations and emissions PM at steady operation modes, the type has been ed and the most reliable regression depen-dence has been established – a second-order polynomial model that allows us to estimate the values of Cpt, PTmass and PTp in the ranges of variation of the parameters n and L – 1000 ... 2000 min-1 and 25 ... 100%. The RSM of the established dependencies when determining the indicated values is comparable with the errors of microtunnels MKT-2 and is ± 0.0042 g/mn3, ± 2.02 g/h, ± 0.077 g/kWh. A dependence for indirectly determining the mass concentration of PM in the exhaust gases at unsteady diesel operating modes, which are characterized by a duration of 10 ... 30 s and ranges of variation of the parameters n, L, Δn/Δt and ΔL/Δt, given in dimensionless form: 0.4 ... 0.8, 0.3 ... 1.0, -0.2 ... 0.2 and -0.35 ... 0.35, respectively, has been established. The deviation of the calculated and experimental data when using this dependence is ± 0.005 ... 0.006 g/kg, which is comparable with the sensitivity limit of MKT-2. A satisfactory accuracy and practical suitability of the indirect optical-gravimetric method for controlling PM concentrations and emissions at steady-state diesel engine operating modes were proposed and experimentally confirmed. | en |
