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The influence of the mass composition of a water−fuel emulsion on the ecological characteristics of a diesel engine was evaluated. Research was performed on the diesel engine MMZ D-245.10 (4-cylinder, D = 110 mm, S = 125 mm) fueled with an emulsion having a water content of 10%, 20%, and 30% by weight. A noticeable drop of nitrogen oxide emissions with a growth of the mass fraction of water in the emulsion was revealed, which is a consequence of a decrease in the cycle’s average temperature. During research into engine operation using emulsions, its structure-borne noise was evaluated. For all engine operation modes investigated, the lowest noise level was achieved when the engine was running on diesel fuel (DF), and the highest when an emulsion consisting of 70% DF and 30% water was used.

A three-dimensional (3D) geometry model of twin screw expander has been developed in this paper to measure and analyze geometric parameters such as groove volume, suction port area, and leakage area, which can be described as functions of rotation angle of male rotor. Taking the suction loss, leakage loss, and real gas effect into consideration, a thermodynamic model is developed using continuity and energy conservation equation. The developed model is verified by comparing predicted results of power output and internal efficiency with experimental data. Based on the model, the relationship between mass flow rate through inlet port and leakage path with rotation angle of male rotor as well as effects of the inlet parameter and operating parameter on the performance of the expander are analyzed.