Structure, elements, and parameters of the gas exchange system in a diesel engine, determining the pressure, temperature and heat transfer in the cylinder

The materials and methods of computational and experimental study of the gas exchange system are described. The analysis of the functional effect of air supply and gas disposal processes on the thermal and mechanical loading of elements limiting the internal cylinder space of a diesel engine, in particular a piston, is advisable using a systematic block-hierarchical approach. The expediency of analyzing the structure, elements and parameters of gas exchange processes is substantiated. The features of a diesel engine test bench are described in order to study the effect of the parameters of the intake subsystem of the gas exchange system on changes in gas pressure and temperature in the diesel cylinder. The features of special measuring equipment for indicating the pressure of gases in the cylinder as a function of the angle of rotation of the crankshaft are reflected by the MAI-2 electropneumatic indicator with an inductive TDC position sensor and a contact-type diaphragm pressure receiver, which allows recording multi-cycle pressure indicator diagrams, and an electronic two-beam oscilloscope of the English company Cossor. The functional and design features of the elements of the fresh charge intake subsystem are considered. It is noted that an increase in the charge air pressure at a constant temperature is accompanied by an increase in the maximum pressure, maintaining the maximum rate of pressure increase, reducing the maximum temperature of gases in the cylinder and exhaust gases at the outlet of the diesel cylinder. A similar change in these parameters, except for an increase in the maximum rate of pressure increase, is observed when the temperature of the charge air decreases at constant pressure. The decrease in the specific effective fuel consumption of diesel with an increase in the charge air density can be explained by an increase in the excess air coefficient, a reduction in duration and a decrease in relative heat losses during combustion. The influence of the intensity of movement of the air charge at the inlet, characterized by a vortex ratio, on the maximum pressure, the rate of pressure increase, the temperature of gases in the cylinder, the nature of their change and the effective indicators of the diesel engine: specific effective fuel consumption, the coefficient of excess air, the temperature of exhaust gases at the outlet from the cylinder at constant power and air consumption is analyzed. It is revealed that there is an optimal vortex ratio that provides minimum values of maximum pressure, the rate of increase in pressure and temperature of gases in the cylinder with an insignificant change in the fuel efficiency of the diesel engine.