Influence of Dimethyl Ether Combustion in the Compression-Ignition Engine on the Peak and Effective Measures of the Vibroacoustic Process and Toxic Compounds Emission.

The scientific paper conducted empirical studies related to the effectiveness of the use of dimethyl ether as an additive to diesel fuel and its impact on the efficiency of the mixture creation and combustion process. The measure of the above quality was the observation and parametric assessment of the then generated vibroacoustic processes, the relations of which were assessed using the peak and effective value of vibration accelerations, and also assessment of toxic exhaust gas components. The transformation of the main process into its vibroacoustic and emission representations allowed for the construction of mathematical relations between them, expressed in a specific engine operating space, and a vector of tribological parameters, expressing specific friction changes occurring in the critical kinematic pairs of the combustion and mixture formation area. The tests were carried out on a single-cylinder research engine with direct fuel injection, in stationary conditions with a time-invariant control vector. As part of the procedures, a constant and optimal value of thermodynamic parameters defining the thermal state of the engine was maintained, minimizing external forces and disturbances that could affect the active value of the measurement signal. The research results are empirical vibroacoustic and emission characteristics for various signal domains and their parameterization supplemented with a detailed analysis of the results, developed vibroacoustic and emission mathematical models depending on the operating parameters, type of fuel and combustible mixture formation variables, supplemented with an assessment of their degree of mapping to the dynamic source process. The dimethyl ether application resulted in a emission reduction by the coefficient: 24.3-57.8 (hydrocarbons), 1.03-1.24 (carbon monoxide), and an increase in nitrogen oxides in the range of 1.01-1.08. The use of dimethyl ether as a base fuel component has a positive effect on reducing the peak value of vibration accelerations in the range of 16-28%, and the root mean square in the range of 14-65%. [ABSTRACT FROM AUTHOR]