IMPLEMENTATION ON THE BASIS OF A MICROTUNNEL OF THE DYNAMIC CONTROL METHOD OF PARTICULATE MATTER CONCENTRATION IN THE EXHAUST GASES OF DIESEL ENGINES

Abstract

Modern methods of dynamic control of particulate matter emissions from diesel engine exhaust gases are analyzed. The principles of operation and technical characteristics of the methods are considered: Method for Real-Time Mass Microbalances, Tapered element oscillating microbalance - TEOM, Quartz Crystal Microbalance - QCM and Laser Induced Incandescence - LII. It was found that the accuracy of these methods provides the ability to measure ultra-low concentrations of solid particles with a sensitivity of up to ± 2 μg/m3 in the ranges: 1.25 ... 0.25 ... 0.063 mg/m3 in accordance with the requirements of Euro-3, Euro -4.5 and Euro-6, and the speed of these methods provides the ability to control instantaneous values of particulate matter emissions during the execution of transient diesel test cycles: European Transient Cycle (ETC), Worldwide Transient Vehicle Cycle (WTVC), Worldwide heavy-duty transient cycle (WHTC) and others. Based on the analysis of these methods, world and domestic experience in the creation and operation of systems for environmental diagnostics of diesel engines, a method for dynamic control of the concentration of solid particles with an optical sensitive element is proposed for practical application. The essence of this method lies in the indirect determination of the instantaneous concentrations of solid particles by the optical opacity index - the smoke of diesel exhaust gases using the empirical relationship between these values, which is established during the calibration of the optical particle detector with the gravimetric system - the MKT-2 microtunnel. The following are considered: a schematic diagram of this method, technical means for its implementation, which include: a partial-flow system for diluting exhaust gases with air with MKT-2 and a dynamic particle detector. The maximum permissible values of the dilution coefficients of exhaust gases with air in MKT-2 have been established, at which the required accuracy of measurements of particulate concentrations by an optical detector with a sensitivity of ± 0.1% on the Hartridge scale is provided, while the levels of diesel particulate emissions comply with the requirements of Euro 3-6.