Experimental Study of the Electric Discharge System for Lowering the Toxicity of Exhaust Gases of the D-243 Diesel Engine

Abstract

537.525The results of the experimental studies of a full-scale plasmachemical system for lowering the toxicity of exhaust gases of the D-243 diesel engine are presented. It has been shown that under nominal operating conditions of the D-243 engine the device decreases the content of soot by more than 95% and lowers the concentration of nitrogen oxides by 24% under combined conditions of discharge power supply and at a value of the specific energy input up to 2.5 W⋅h/m 3 .One of the main directions in increasing the ecological indices of modern automobiles and tractors is the application of a complex of measures for additional physicochemical cleaning of exhaust gases from toxic components in the process of discharge. These measures are realized in practice by using special gas cleaners installed in the discharge system. Of the known gas-cleaning techniques, the most promising for mobile machinery equipped with internal combustion engines is the use of electric discharge systems for lowering the toxicity of exhaust gases that are capable, at moderate energy inputs, of providing a high degree of cleaning gas flows from both aerosol particles and toxic gaseous components without using the expensive materials (platinum, palladium) used in catalytic cleaners.The volt-ampere characteristics of the electrode system of the plasmachemical reactor for the D-243 engine at various temperatures of the flow of exhaust gases are given in Fig. 1.Consider the results of experimental studies of the operating efficiency of the plasmachemical system [1-3] depending on the value of the voltage powering the reactor and the energy input into the discharge for different operating conditions of the engine (Fig. 2). The obtained characteristics permit establishing a relation between the value of the voltage powering the reactor and the degree of cleaning exhaust gases as well as determining the highest possible degree of cleaning the exhaust gases of the D-243 diesel by the proposed electric discharge system depending, in the first place, on its constructional arrangement and the concentration of soot in the exhaust gases of the diesel.At some critical voltage (6.5-8 kV) on the electrode system of cleaning gases from soot, the soot content does not decrease at all or decreases insignificantly (by 1-2%). As the voltage on the electrode system is increased, the content of soot in the exhaust gases begins to decrease monotonically. At a voltage exceeding 14-15 kV, the reactor goes to the saturation regime. Further increase in the voltage is pointless because, in so doing, the specific energy input markedly increases with a small additional value of the degree of cleaning. An increase in the discharge powering voltage from 15 to 17 kV for the nominal discharge of gases leads to an increase in the power approximately from 320 to 520 W (by a factor of 1.6), while the degree of cleaning increases approximately from 92 to 95%. Obviously, to obtain a higher degree of cleaning with a moderate specific energy input into the discharge (up to 0.5 W⋅h/...